Rotary Table Device

Abstract

To provide a rotary table device capable of lowering the height of a work from a table surface and improving the mounting rigidity of the work. [Solution] The rotary table device (1) comprises a rotating table (2) having a table surface (20) and a recess (21), a frame (4) that rotatably supports the rotating table (2) from its back side, a clamping unit (5) fixedly positioned within the recess of the rotating table, a shaft (3) attached to the frame and supplying fluid to the clamping unit, a power transmission fluid passage (38) that extends from the shaft through the rotating table to within the clamping unit and passes fluid for clamping or unclamping a work holder by a clamping mechanism, and a sealing mechanism (25) that seals the gap between the inner wall surface of the recess of the rotating table and the outer wall surface of the clamping mechanism.

Description

[Technical field]

[0001] The present invention relates to a rotary table device, and more particularly to a rotary table device having a table surface on one axial end side of a rotation axis. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a clamping device as disclosed in European Patent Application Publication No. 004385659 (Patent Document 1) has been known as a device for fixing a workpiece.

[0003] The clamping device of Patent Document 1 uses a fluid and a spring to move a piston up and down to engage a recess in the clamping bolt with a locking ball, thereby retracting the clamping bolt, thereby fixing the jig plate that holds the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 004385659 Summary of the Invention [Problem to be solved by the invention]

[0005] The clamping device as described in Patent Document 1 is fixed onto the flat table surface of the rotary table device, and a fixture plate that holds the workpiece is held on the clamping device. This increases the height of the workpiece from the table surface, narrowing the area for machining the workpiece, making it difficult to machine a large workpiece or a small machine with a small Z-axis stroke for cutting. Furthermore, the mounting rigidity of the workpiece decreases as the height of the workpiece from the table surface increases.

[0006] The present invention has been made to solve the above-mentioned problems, and its object is to provide a rotary table device that can lower the height of the workpiece from the table surface and improve the mounting rigidity of the workpiece. [Means for solving the problem]

[0007] For this purpose, a rotary table device according to one embodiment of the present invention comprises a rotary table having a table surface provided on one axial end side of the rotation axis and a recess extending from the table surface toward the other axial end, a frame which rotatably supports the rotary table from its back side, a work holder which holds a workpiece, a clamp unit fixedly arranged in the recess of the rotary table and including a clamp mechanism which clamps the work holder by fluid pressure, a shaft attached to the frame and supplies fluid to the clamp unit, a power transmission fluid passage which extends from the shaft through the rotary table into the clamp unit and passes fluid for clamping or unclamping the work holder by the clamp mechanism, and a sealing mechanism which seals the gap between the inner wall surface of the recess of the rotary table and the outer wall surface of the clamp mechanism.

[0008] Preferably, the clamping mechanism includes a receiving hole that receives the downward leading-in portion of the work holder, and a fluid pressure gripping mechanism that mechanically grips the downward leading-in portion received in the receiving hole from its outer diameter side using fluid pressure, and the rotary table device further includes a clamping mechanism cleaning fluid passage extending from the shaft through the rotary table to the receiving hole of the clamping mechanism for cleaning the receiving hole.

[0009] Preferably, the cleaning device further comprises a table surface cleaning fluid passage extending from the shaft through the rotary table to the table surface, the fluid passage being a passage for supplying fluid onto the table surface to clean the table surface.

[0010] Preferably, the work holder includes a work support portion for holding a work, and a fluid pressure work holding mechanism for mechanically displacing the work support portion using fluid pressure, and the rotary table device is provided with a work holder driving fluid passage connected to the fluid pressure work holding mechanism of the work holder, which is a passage for supplying a fluid for driving the work support portion and extends from the shaft through the rotary table spindle to the table surface.

[0011] Preferably, the clamp mechanism further includes a cap having an extension that contacts a wall surface of the receiving hole, being slidable within the receiving hole, and being biased toward one end in the axial direction.

[0012] Preferably, the rotating table has a plurality of recesses and a plurality of clamping mechanisms, the clamping mechanisms being respectively arranged in the plurality of recesses, and when the work holder is clamped by the clamping mechanisms, the lower surface of the work holder abuts against the end surface of the table surface. Effect of the Invention

[0013] According to the rotary table device of the present invention, the height of the workpiece from the table surface can be reduced and the mounting rigidity of the workpiece can be improved. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing a schematic configuration of a rotary table apparatus and a workpiece holder having a workpiece attached thereto according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the rotary table device of FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing a workpiece, a workpiece holder, and a clamp unit. [Figure 4] 5(A) to 5(E) are partial cross-sectional views showing the clamping operation of the clamp unit. [Diagram 5] FIG. 11 is a cross-sectional view of a rotary table device according to a second embodiment of the present invention. [Figure 6]FIG. 11 is a cross-sectional view of a rotary table device according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of a rotary table device according to a fourth embodiment of the present invention. [Figure 8] 5(A) to 5(C) are cross-sectional views showing the operation of the work holder to hold the workpiece. [Figure 9] FIG. 11 is a plan view of a rotary table device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0016] <Embodiment 1> Fig. 1 is a schematic cross-sectional view showing the general configuration of a rotary table apparatus and a work holder with a work attached according to an embodiment of the present invention. The rotary table apparatus 1 will be generally described with reference to Fig. 1. In Fig. 1, the direction indicated by arrow A is referred to as one end side or upward in the axial direction of the rotation axis O, and the direction opposite to arrow A is referred to as the other end side or downward in the axial direction.

[0017] 1, the rotary table device 1 includes a rotary table 2, a frame 4 that rotatably supports the rotary table 2 from the back side (below), and a shaft 3 attached to the frame 4. The rotary table 2, shaft 3, and frame 4 are the main elements of the rotary table device 1, and are formed, for example, from a rigid body.

[0018] The turntable 2 has a through hole 2a extending along the rotation axis O, and a shaft 3 passes through this through hole 2a. The turntable 2 has a table surface 20 provided at one axial end side (upper side) of the rotation axis O, and a recess 21 recessed from the table surface 20 toward the other axial end side (lower side). A clamp unit 5 is fixedly disposed in this recess 21. A work holder 7 having a workpiece 8 attached thereto is detachably fixed to the turntable 2 via the clamp unit 5. FIG. 1 shows a state before the work holder 7 is clamped by the clamp unit 5.

[0019] Fig. 2 is a cross-sectional view of the rotary table device of Fig. 1, Fig. 3 is a cross-sectional view showing the work, the work holder, and the clamp unit, and Fig. 4 is a partial cross-sectional view showing the clamping operation of the clamp mechanism of the clamp unit. A specific configuration of the rotary table device will be described in detail with reference to Figs. 2 to 4. As in Fig. 1, the direction indicated by the arrow A in Figs. 2 and 3 is referred to as one end side or upward in the axial direction of the rotation axis O, and the direction opposite to the arrow A is referred to as the other end side or downward in the axial direction. First, the rotary table 2, the shaft 3, and the frame 4 will be described in detail with reference to Fig. 2.

[0020] As described above, the clamp unit 5 for clamping the workpiece holder 7 is disposed in the recess 21 formed on the table surface 20 side of the turntable 2. The turntable 2 is rotated about the rotation axis O by a drive device (not shown) provided on the frame 4. The rotation position of the turntable 2 is detected by a control unit (not shown), and the drive device is controlled to set the turntable 2 to the desired index angle. In other words, the turntable 2 is a rotating member.

[0021] As described above, the table surface 20 is a flat surface provided above the rotary table 2, and the recess 21 recessed downward is provided at approximately the center of the table surface 20. The recess 21 is typically approximately cylindrical, and the bottom surface forming the recess 21 is preferably also a flat surface. In this embodiment, one recess 21 is provided at approximately the center of the table surface 20. In this embodiment, when the clamp unit 5 is arranged and fixed in the recess 21, the upper end surface of the clamp unit 5 and the table surface 20 are approximately flush with each other. Note that the upper end surface of the clamp unit 5 does not necessarily have to be approximately flush with the table surface 20, and may be higher than the height of the table surface 20, or may be lower than the height of the table surface 20, with the clamp unit 5 recessed into the recess 21.

[0022] 2, the turntable 2 includes a joint sleeve 22 and a circular table main body 23 that surrounds the outer periphery of the joint sleeve 22. The joint sleeve 22 and the circular table main body 23 are connected by, for example, a bolt (not shown).

[0023] 2, the rotary table device 1 is provided with a sealing mechanism 25 that seals the gap between the inner wall surface of the recess 21 of the turntable 2 and the outer wall surface of the clamp unit 5. This gap is a groove provided on the upper edge of the peripheral wall of the recess 21 of the turntable 2, and the sealing mechanism 25 is disposed in this groove.

[0024] The sealing mechanism 25 includes a seal 26 located on the table surface 20 side, and an O-ring 27 located below the seal 26. Both the seal 26 and the O-ring 27 are elastic bodies, for example made of synthetic resin. The O-ring 27 is an annular member, and is formed such that its inner diameter is smaller than the outer diameter of the outer wall surface of the clamp unit 5. This allows the O-ring 27 to be tightly fixed to the outer wall surface of the clamp unit 5 by the elastic force of the O-ring 27 itself.

[0025] The sealing mechanism 25 only needs to seal the gap between the inner wall surface of the recess 21 of the turntable 2 and the outer wall surface of the clamp unit 5, and may be formed by either the seal 26 or the O-ring 27. In addition, although the gap is described as a groove provided in the turntable 2, it may be provided in the clamp unit 5, or may not be provided intentionally in order to accommodate the sealing mechanism 25.

[0026] The shaft 3 is a non-rotating member, and is supported by a rolling bearing (not shown) provided in the joint sleeve 22. The outer circumferential surface of the shaft 3 faces the inner circumferential surface of the joint sleeve 22. The shaft 3 is also attached to a frame 4, and supplies fluid to the clamp unit 5. The frame 4 is a non-rotating member like the shaft 3, and forms a frame body of the rotary table device 1.

[0027] As shown in the figure, the rotary table apparatus 1 includes a power transmission fluid passage 38 that extends from the shaft 3 through the rotary table 2 into the clamp unit 5 and passes a fluid for clamping or unclamping the workpiece holder 7 (FIG. 1). Specifically, the power transmission fluid passage 38 is formed by a shaft side fluid passage 39, a joint sleeve side fluid passage 29, and a table side fluid passage 28. The fluid that passes through the power transmission fluid passage 38 is, for example, a liquid such as air or hydraulic pressure.

[0028] The shaft-side fluid passage 39 is provided inside the shaft 3, and has a fluid inlet (power input port) provided on the outer circumferential surface of the shaft 3. Specifically, the shaft-side fluid passage 39 includes a shaft-side lower horizontal passage extending horizontally from the power input port on the outer circumferential surface of the shaft 3, a shaft-side vertical passage connected to an end of the shaft-side lower horizontal passage and extending along the rotation axis O of the shaft 3, and a shaft-side upper horizontal passage connected to an upper part of the shaft-side vertical passage and extending horizontally.

[0029] The joint sleeve side fluid passage 29 is a passage that is connected to the shaft side upper horizontal passage of the shaft side fluid passage 39. At the portion where the joint sleeve side fluid passage 29 is connected to the shaft 3, an annular groove 24 is provided along the inner circumference of the joint sleeve 22. The joint sleeve side fluid passage 29 is connected to the annular groove 24 and extends in the horizontal direction.

[0030] The table-side fluid passage 28 includes a lower table-side horizontal passage connecting to the joint-side fluid passage 29 and extending horizontally, a table-side vertical passage connecting to an end of the lower table-side horizontal passage and extending vertically, and an upper table-side horizontal passage connecting to the upper end of the table-side vertical passage, extending horizontally, and connected to the clamp unit 5. In this way, the power transmission fluid passage 38 is formed by the shaft-side fluid passage 39, the joint-side fluid passage 29, and the table-side fluid passage 28, and is a passage that passes the fluid input from the power input port through the clamp unit 5.

[0031] Next, the clamp unit 5 will be described with reference to Fig. 3. As described above, the clamp unit 5 is fixedly disposed within the recess 21 of the rotary table 2, and is a device that clamps the workpiece holder 7 that holds the workpiece 8 by fluid pressure. Here, the workpiece holder 7 includes a holder body 70 that holds the workpiece 8, and an attachment part 72 that is detachably attached to the holder body 70. A screw hole 71 having a screw groove for fixing the attachment part 72 is provided on the underside of the holder body 70.

[0032] The mounting portion 72 typically has a screw formed in an upper portion 73, and a groove portion 74a extending in the circumferential direction formed in a lower portion 74. The lower portion 74 is a downward retracting portion that is received (retracted) into a receiving hole 52 of the clamp unit 5, which will be described later, and clamped. The mounting portion 72 may be fixed to the retainer body 70.

[0033] The clamp unit 5 typically has an outer shape of a flattened cylinder. The clamp unit 5 includes a clamp body 50 and a clamp mechanism 51 that is provided in the clamp body 50 and clamps the workpiece holder 7 that holds the workpiece 8 by fluid pressure. The clamp body 50 is a frame that holds the clamp mechanism 51 from the outside.

[0034] The clamping mechanism 51 has a receiving hole 52 that receives the downward retraction portion 74 of the work holder 7, a fluid pressure gripping mechanism 53 that grips the downward retraction portion 74 received in the receiving hole 52 from its outer diameter side by fluid pressure, and a cap 62 that can slide up and down within the receiving hole 52. The receiving hole 52 is located approximately in the center of the clamping unit 5 and extends up and down along the rotation axis O.

[0035] The fluid pressure grasping mechanism 53 generally includes a piston 54 that can move up and down, an upper chamber 55 located above the piston 54, a lower chamber 56 located below the piston 54, a first spring 57 that urges the piston 54 to its upper position, and a lock ball 58 that is moved by the piston 54.

[0036] The portion of piston 54 that comes into contact with lock ball 58 forms inclined portion 54a that inclines downward toward the inner diameter side. Fluid is supplied to upper chamber 55 and lower chamber 56 through fluid supply port 59, and the fluid is discharged through fluid discharge port 61, but a fluid supply path and a fluid discharge path may be provided for upper chamber 55 and lower chamber 56, respectively. The above-mentioned power transmission fluid passage 38 is connected to fluid supply port 59, and the fluid pressure of fluid pressure grasping mechanism 53 is introduced through power transmission fluid passage 38.

[0037] The cap 62 is intended to prevent, for example, cutting chips and the like from entering the receiving hole 52. The cap 62 is in the shape of a cylinder with a bottom that opens downward, and has an extension portion 63 that extends radially outward from the lower end of the bottomed cylinder portion. The extension portion 63 comes into contact with the hole wall surface of the receiving hole 52, and has a slip-out prevention function that prevents the cap 62 from slipping out of the receiving hole 52. The cap 62 is urged by a second spring 64 toward one end side (upward) in the axial direction.

[0038] Next, the operation of the clamp mechanism will be described with reference to Fig. 4. First, as shown in Fig. 4(A), when the workpiece retainer 7 is not received in the receiving hole 52, the lock ball 58 is in contact with the inclined portion 54a of the piston 54 and supported upward. Furthermore, the cap 62 is biased to an upward position by the second spring 64.

[0039] 4(B), by supplying fluid to the upper chamber 55 through the fluid supply port 59 and discharging the fluid from the lower chamber 56 through the fluid discharge port 61, the first spring 57 is contracted and the piston 54 is moved downward. This causes the lock ball 58 in contact with the inclined portion 54a of the piston 54 to move downward.

[0040] 4(C) and 4(D), the downward retraction portion 74 of the work holder 7 is inserted into the receiving hole 52, and the second spring 64 is contracted to press down the cap 62. The extension portion 63 of the cap 62 slides downward while abutting against the wall surface of the receiving hole 52.

[0041] As shown in FIG. 4(E), when downward retraction portion 74 is inserted to a predetermined position, fluid is supplied to lower chamber 56 through fluid supply port 59 and discharged from upper chamber 55 through fluid discharge port 61. Furthermore, piston 54 is moved upward by the upward biasing force of first spring 57, and lock ball 58 is engaged with groove portion 74a of downward retraction portion 74.

[0042] In this way, the work holder 7 can be held on the rotary table device 1 via the clamp mechanism 51 in the procedure shown in Figures 4(A) to 4(E), so that the work holder 7 can be held mechanically.

[0043] In the rotary table device 1 of this embodiment, the clamp unit 5 is disposed in the recess 21 of the turntable 2, so that the height of the work from the mounting surface can be reduced and the mounting rigidity of the work can be improved. Also, the power transmission fluid passage 38 can be built into the rotary table device 1, and the power transmission fluid passage 38 is not exposed to the outside, so that a smart shape can be achieved. Furthermore, a seal mechanism 25 is provided in the gap between the recess 21 of the turntable 2 and the clamp unit 5, so that chips of the work 8 can be prevented from entering the gap.

[0044] <Embodiment 2> Fig. 5 is a cross-sectional view of a rotary table device according to a second embodiment of the present invention. A rotary table device 1A according to the second embodiment of the present invention will be described with reference to Fig. 5. The rotary table device 1A of the second embodiment differs from the configuration of the first embodiment in that it has a structure including a clamp mechanism cleaning fluid passage 36A. Only the differences from the structure shown in the first embodiment will be described in detail below.

[0045] The clamp mechanism cleaning fluid passage 36A is a passage for cleaning the receiving hole 52 of the clamp unit 5. The fluid passing through the clamp mechanism cleaning fluid passage 36A is typically air, but may be a liquid such as a coolant.

[0046] The clamp mechanism cleaning fluid passage 36A extends from the shaft 3 through the rotary table 2 to the receiving hole 52 of the clamp mechanism 51. The clamp mechanism cleaning fluid passage 36A is provided inside the shaft 3, and has a fluid inlet (fluid input port) provided on the outer circumferential surface of the shaft 3. Specifically, the clamp mechanism cleaning fluid passage 36A includes a horizontal passage extending laterally inside the shaft 3, and a vertical passage connected to the inner diameter side of the horizontal passage, extending vertically, and connected to the clamp unit 5. The vertical passage extends inside the shaft 3 and the rotary table 2.

[0047] By providing the clamp mechanism cleaning fluid passage 36A, chips and the like in the receiving hole 52 can be efficiently removed before the downward retraction portion 74 (Figure 3) of the work holder 7 is inserted into the receiving hole 52 of the clamp unit 5.

[0048] <Embodiment 3> FIG. 6 is a cross-sectional view of a rotary table device according to a third embodiment of the present invention. A rotary table device 1B according to the third embodiment of the present invention will be described with reference to FIG. 6. The third embodiment differs from the first embodiment in that, in addition to the configuration thereof, a table surface cleaning fluid passage 37B is provided. Although FIG. 6 does not show the power transmission fluid passage 38 described in the first embodiment, it is assumed that the power transmission fluid passage 38 is formed. Only the differences from the structure shown in the first embodiment will be described in detail below.

[0049] The table surface cleaning fluid passage 37B is a passage that supplies fluid onto the table surface 20 in order to clean the table surface 20 of the turntable 2. The fluid that passes through the table surface cleaning fluid passage 37B is typically air, but may be a liquid such as a coolant.

[0050] The table surface cleaning fluid passage 37B differs from the above-mentioned power transmission fluid passage 38 in that it extends from the shaft 3 through the turntable 2 to the table surface 20, but other than that, the configuration is substantially the same. Specifically, the table surface cleaning fluid passage 37B is formed by the shaft side fluid passage 39, the joint side fluid passage 29, and the table side fluid passage 28B.

[0051] The table side fluid passage 28B includes a table side horizontal passage that is connected to the joint side fluid passage 29 and extends horizontally, and a table side vertical passage that is connected to the outer diameter side end of the table side horizontal passage, extends vertically, and is connected to the table surface 20. By providing the table surface cleaning fluid passage 37B, chips and the like of the workpiece 8 on the table surface 20 can be efficiently removed.

[0052] In addition to the table surface cleaning fluid passage 37B described in this embodiment, the clamp mechanism cleaning fluid passage 36A described in the second embodiment may be further provided.

[0053] <Fourth embodiment> FIG. 7 is a cross-sectional view of a rotary table apparatus according to a fourth embodiment of the present invention, and FIGS. 8(A) to (C) are views for explaining the operation of the work holder to hold a workpiece. A rotary table apparatus 1C according to the fourth embodiment of the present invention will be explained with reference to FIG. 7 and FIGS. 8(A) to (C). The fourth embodiment differs from the other embodiments in the structure in which a work holder driving fluid passage 37C is provided. Note that FIG. 7 does not show the power transmission fluid passage 38 described in the first embodiment, but it is assumed that the power transmission fluid passage 38 is formed as in the first embodiment. Only the differences from the structure shown in the first embodiment will be explained in detail below.

[0054] As shown in Fig. 7, the work holder driving fluid passage 37C is a passage for supplying a fluid for driving the work support part 75C of the work holder 7C to the work holder 7C. The fluid passing through the work holder driving fluid passage 37C is typically air, but may be a liquid such as a coolant. The work holder driving fluid passage 37C is formed by the shaft side fluid passage 39, the joint side fluid passage 29, the table side fluid passage 28C, and the work holder side fluid passage 79C.

[0055] Here, the configuration of the work holder 7C will be described with reference to Fig. 8(A). The holder body 70C of the work holder 7C includes a work support portion 75C that holds the work 8, and a fluid pressure work holding mechanism 78C that mechanically displaces the work support portion 75C using fluid pressure. Specifically, the work support portion 75C includes a work holder 76C that directly holds the work 8, and a piston 77C that is connected to the work holder 76C and moves the work holder 76C. The fluid pressure work holding mechanism 78C also includes a work holder side fluid passage 79C that supplies fluid, and a piston chamber 81C in which the piston 77C is disposed and in which the piston 77C is moved by the fluid supplied by the work holder side fluid passage 79C.

[0056] Next, referring to FIG. 7 and FIG. 8(A)-(C), the operation of mechanically holding the workpiece 8 on the workpiece holder 7C will be described. FIG. 7 and FIG. 8(A) show a state before the workpiece 8 is fixed. First, as shown in FIG. 8(B), the workpiece 8 is placed on the upper surface of the workpiece holder 7C. Next, fluid is fed in the order of the shaft-side fluid passage 39, the joint-side fluid passage 29, the table-side fluid passage 28C, and the workpiece holder-side fluid passage 79C shown in FIG. 7 to supply the fluid to the piston chamber 81C. As a result, as shown in FIG. 8(C), the piston 77C moves downward, and the workpiece presser 76C also moves downward accordingly. As a result, the workpiece holder 7C mechanically holds the workpiece 8. The workpiece 8 can be removed by discharging the fluid from the workpiece holder driving fluid passage 37C (FIG. 7), and the above-mentioned procedure can be reversed.

[0057] By providing the workpiece holder driving fluid passage 37C in the rotary table device 1, the operation of holding the workpiece 8 on the workpiece holder 7C can be performed mechanically.

[0058] The shaft side fluid passage 39, the joint side fluid passage 29, and the table side fluid passage 28C of the workpiece holder driving fluid passage 37C in this embodiment may be used in combination with the table surface cleaning fluid passage 37B described in embodiment 3. Furthermore, in addition to the table surface cleaning fluid passage 37B described above, the clamp mechanism cleaning fluid passage 36A described in embodiment 2 may be further provided.

[0059] <Embodiment 5> Fig. 9 is a plan view of a rotary table device according to embodiment 5 of the present invention. A rotary table device 1D according to embodiment 5 of the present invention will be described with reference to Fig. 9. Embodiment 5 differs in that a plurality of clamp units 5 is provided. Only the differences from the structure shown in embodiment 1 will be described in detail below.

[0060] 9, in the rotary table device 1D of this embodiment, a plurality of recesses 21 are provided on a table surface 20, and a clamp unit 5D is fixedly disposed in each of the plurality of recesses 21. Specifically, four recesses 21 are provided, and a clamp unit 5D is disposed in each of the four recesses 21. Each of the plurality of clamp units 5D includes the above-mentioned seal mechanism 25 and power transmission fluid passage 38.

[0061] When multiple clamp units 5D are attached to multiple recesses 21, respectively, if the height of the upper surface of the clamp unit 5D is higher than the table surface 20, it is necessary to make the height of the upper surface of all the clamp units 5D the same. Therefore, multiple clamp mechanisms 51 are arranged in multiple recesses 21, respectively, so that when the work holder 7 is clamped by the clamp mechanisms 51, the lower surface of the work holder 7 comes into contact with the end surface of the table surface 2. Specifically, the height of the upper surface of the clamp unit 5D is made flush with or lower than the table surface 20, so that the clamp unit 5D is recessed below the table surface 20.

[0062] The rotary table device 1D of the present embodiment is provided with a plurality of recesses 21, and a clamp unit 5D is disposed in each of the plurality of recesses 21, so that workpieces 8 of various sizes can be machined.

[0063] Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications and variations can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope. [Industrial Applicability]

[0064] The present invention is advantageously used in machine tools. [Explanation of symbols]

[0065] 1,1A,1B,1C,1D rotary table device, 2 rotating table, 3 shaft, 4 frame, 5,5D clamp unit, 7,7C workpiece holder, 8 work, 20 table surface, 21 recess, 25 sealing mechanism, 36A clamp mechanism cleaning fluid passage, 37B table surface cleaning fluid passage, 37C workpiece holder driving fluid passage, 38 power transmission fluid passage, 51 clamp mechanism, 52 receiving hole, 53 fluid pressure gripping mechanism, 62 cap, 63 extension portion, 70,70C holder body, 74 downward retraction portion (lower portion), 75C workpiece support portion, 78C fluid pressure workpiece holding mechanism.

Claims

1. a rotary table having a table surface provided on one end side in the axial direction of a rotation axis and a recessed portion recessed from the table surface toward the other end in the axial direction; a frame that rotatably supports the rotary table from a rear side thereof; a clamp unit including a workpiece holder that holds a workpiece, and a clamp mechanism that is fixedly disposed in a recess of the rotary table and clamps the workpiece holder by fluid pressure; a shaft attached to the frame and supplying fluid to the clamp unit; a power transmission fluid passage extending from the shaft through the rotary table into the clamp unit for passing a fluid for clamping or unclamping the work holder by the clamp mechanism; a sealing mechanism that seals a gap between an inner wall surface of the recess of the rotary table and an outer wall surface of the clamp unit.

2. The clamping mechanism includes a receiving hole that receives the downward lead-in portion of the work holder, and a fluid pressure gripping mechanism that mechanically grips the downward lead-in portion received in the receiving hole from an outer diameter side thereof using fluid pressure, 2. The rotary table apparatus according to claim 1, further comprising a clamp mechanism cleaning fluid passage extending from the shaft through the rotary table to the receiving hole of the clamp mechanism for cleaning the receiving hole.

3. 3. The rotary table apparatus according to claim 1, further comprising a table surface cleaning fluid passage extending from the shaft through the rotary table to the table surface, the table surface being a passage for supplying fluid onto the table surface to clean the table surface.

4. The workpiece holder includes a workpiece support portion that holds a workpiece, and a fluid pressure workpiece holding mechanism that mechanically displaces the workpiece support portion by using fluid pressure, The rotary table device according to claim 1 or 2, further comprising a work holder driving fluid passage that is connected to a fluid pressure work holding mechanism of the work holder, is a passage for supplying a fluid for driving the work support portion, and extends from the shaft through the rotary table to the table surface.

5. The rotary table device according to claim 2, wherein the clamping mechanism further includes a cap having an extension portion that contacts a hole wall surface of the receiving hole, that is slidable within the receiving hole, and that is biased toward one end in the axial direction.

6. The rotary table has a plurality of recesses. The clamp mechanism is provided in plurality, 3. The rotary table device according to claim 1, wherein the clamping mechanisms are respectively arranged in the recesses, and when the workpiece holder is clamped by the clamping mechanisms, the lower surface of the workpiece holder comes into end surface contact with the table surface.

Images