JP2007290093A - Rotary table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary table performing a highly accurate and stable indexing. <P>SOLUTION: The rotary table is provided with a bed 12, a table 13 rotatably supported on the bed 12, and a rotary joint 22 coaxially disposed with respect to a rotary shaft of the table 3. The rotary joint 22 is equipped with: a distributor 19 which has supply and drainage pipes 27, 28 for supplying and draining with the table 13 and integrally rotates with the table 13; a first central shaft 20 which has the supply and drainage pipes 29, 30 communicating with the supply and drainage pipes 27, 28 of the distributor 19 and is fixed to the bed 12; and a second central shaft 21 which has a rotary encoder 32 for detecting an indexing angle of the table 13 and is fixed to the first central shaft 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary table including a rotary joint.

  Generally, in a machine tool, a workpiece (workpiece) is directly attached to a table with a bolt or a presser foot, or is tightened with a vise or the like to perform cutting. Also, for example, using a milling machine, horizontal machining center, horizontal boring machine, etc., divide the work circumference equally into a certain number, cut while giving rotation to the work, and simultaneously rotate the work in the longitudinal direction When the twist groove is cut by feeding to the table, a cutting mechanism is attached by attaching a rotation mechanism or an indexing mechanism to the table of the machine tool.

  Such a rotary table rotatably supports a disk-shaped table on a central axis provided on the bed, and a drive source such as a servo motor or a step motor is provided on the bed side, while a rack is provided on the table side. The drive gear of the source is engaged with the rack of the table. Further, a rotary joint (rotary joint) is provided between the fixed-side central axis and the rotary-side table, and the rotary joint is sealed with an annular groove for flowing a fluid. An O-ring is provided.

  Therefore, when the drive gear of the drive source is driven and rotated, the drive gear rolls with a reaction force against the rack while meshing with the rack. At this time, the control device attached to the rotary table controls the drive source, and the table can be indexed and rotated by stopping the movement at every arrangement interval of the work attached to the table. The index angle of the table is detected as needed by an index angle detection device such as a rotary encoder provided on the bed side, and the detected index angle is fed back to the control device. . Further, fluid is supplied between the fixed side and the rotary side of the rotary joint by the annular groove, and the annular oil groove is held in a liquid-tight state by the O-ring.

  Such a conventional rotary table is disclosed in Patent Document 1, for example.

JP 2005-46968 A

  However, in the conventional rotary table, when the table is indexed and rotated, sliding resistance is generated in the O-ring provided in the rotary joint, which causes twisting of the central axis. As a result, there is a possibility that the detection accuracy of the index angle by the rotary encoder provided on the central shaft may be lowered.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide a rotary table capable of performing highly accurate and stable indexing.

A rotary table according to a first invention for solving the above-described problems is as follows.
Bed and
A table rotatably supported by the bed;
A rotary joint disposed coaxially with the rotation axis of the table;
The rotary joint is
A distributor having a supply and discharge pipe for supplying and discharging fluid to and from the table and rotating integrally with the table;
A first central axis that has a supply / discharge pipe communicating with the supply / discharge pipe of the distributor and is fixed to the bed;
It has an index angle detecting means for detecting an index angle of the table, and has a second central axis fixed to the bed.

A turntable according to a second invention for solving the above-mentioned problems is as follows.
In the rotary table according to the first invention,
Fixing one end of the first central axis to the bed;
Arranging the second central axis with a gap in the first central axis;
The index angle detection means is provided at one end of the second central axis, and the other end of the second central axis is fixed to one end of the first central axis.

A rotary table according to a third invention for solving the above-described problem is
In the rotary table according to the second invention,
A fitting portion for fitting with the inner peripheral surface of the first central axis is provided on the other end side of the second central axis.

  According to the rotary table of the first invention, a bed, a table rotatably supported by the bed, and a rotary joint arranged coaxially with respect to the rotation axis of the table are provided, and the rotary joint Has a supply and discharge pipe for supplying and discharging fluid to and from the table, a distributor rotating integrally with the table, a supply and discharge pipe communicating with the supply and discharge pipe of the distributor, and the bed A first central axis that is fixed and an index angle detecting unit that detects an indexing angle of the table, and a second central axis that is fixed to the bed, so that the table is rotated with the rotation. Even if the first central axis is twisted, the twist is not transmitted to the second central axis, so that highly accurate and stable indexing can be performed.

  According to the turntable according to the second invention, in the turntable according to the first invention, one end of the first center axis is fixed to the bed, and the second center axis is a gap in the first center axis. The index angle detecting means is provided at one end of the second central axis, while the other end of the second central axis is fixed to one end of the first central axis. Since the support point of the central axis is far from the index angle detecting means, and the twist is generated in the first central axis, the twist is not transmitted to the index angle detecting means. Can be improved. Further, it is possible to easily check and adjust the index angle detection means without removing any of the table, the distributor constituting the rotary joint, the first central axis, and the second central axis. Therefore, maintainability can be improved.

  According to the turntable according to the third aspect of the invention, in the turntable according to the second aspect of the invention, the fitting portion for fitting with the inner peripheral surface of the first center axis is provided on the other end side of the second center axis. Thereby, the centering of the first central axis and the second central axis can be easily performed.

  Hereinafter, a turntable according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of a turntable according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of FIG.

  As shown in FIGS. 1 and 2, the rotary table 1 is attached to a mounting part 11 of a machine tool such as a horizontal machining center or a horizontal boring machine. A bed 12 is fixed on the mounting portion 11, and a table 13 having a substantially disk shape is provided above the bed 12 via a bearing (not shown). A rotating motor 14 is provided on the upper portion of the bed 12, and a worm wheel 16 is provided on the lower surface of the table 13. A worm 15 is connected to the output shaft of the rotating motor 14, and the worm 15 is engaged with the worm wheel 16. That is, the table 13 is supported so as to be rotatable with respect to the bed 12.

  A central hole 17 is formed at a substantially central portion of the bed 12, and a central hole 18 disposed coaxially with respect to the central axis of the central hole 17 is formed at a substantially central portion of the table 13. A step portion 18a protruding inward is formed in the center hole 18, and a cylindrical distributor 19 disposed coaxially with respect to the central axis of the center hole 18 is formed by a bolt (not shown) on the step portion 18a. It is attached. Further, a first central shaft 20 is provided in the distributor 19 so as to be coaxial with the central axis of the distributor 19. Further, the first central shaft 20 includes the first central shaft 20. A second central axis 21 disposed coaxially with the central axis is provided. The distributor 19, the first center shaft 20, and the second center shaft 21 constitute a rotary joint 22. That is, the central hole 17 (bed 12), the central hole 18 (table 13), the distributor 19, the first central axis 20, and the second central axis 21 are all arranged coaxially. The upper end of the bearing 24 is supported on the outer periphery of the first central shaft 20 via the mounting plate 23, and the lower end of the bearing 24 is supported by the center hole 18.

  A flange portion 20 a is formed on the outer periphery of the first central shaft 20, and the flange portion 20 a is supported on the upper end of the center hole 17. On the other hand, a flange portion 21 a is formed at the lower end of the second central shaft 21, and this flange portion 21 a is attached to the lower end of the first central shaft 20 with a bolt (not shown). The second central shaft 21 is formed with a fitting portion 21 b that has a larger diameter than the other shaft portions and that fits with the inner peripheral surface of the first central shaft 20. Thereby, a slight gap S is formed between the inner peripheral surface of the first central shaft 20 and the outer peripheral surface (other shaft portion) of the second central shaft 21. That is, when joining the first central shaft 20 and the second central shaft 21, the second central shaft 21 is fitted into the first central shaft 20, and the fitting portion 21 b is connected to the inner peripheral surface of the first central shaft 20. The first center shaft 20 and the second center shaft 21 are centered, and the flange portion 21a of the second center shaft 21 is fixed to the lower end of the first center shaft 20 with a bolt.

  Between the distributor 19 and the first central shaft 20, O-rings 25 are provided in multiple stages (five in the figure) in the vertical direction, and between the adjacent O-rings 25, the distributor 19 and the first central shaft 20 are provided. An annular oil groove 26 (four in the figure) for the rotary joint is formed by the shaft 20. Further, the distributor 19 is formed with an oil supply pipe 27 and an oil discharge pipe 28 extending in the radial direction. One end of the oil supply pipe 27 and the oil exhaust pipe 28 is connected to the annular oil groove 26, while the other end is not shown. It is connected to the oil supply device via a piping member. On the other hand, the first central shaft 20 and the second central shaft 21 are formed with an oil supply pipe 29 and an oil discharge pipe 30 extending in the axial direction. One end of each of the oil supply pipe 29 and the oil exhaust pipe 30 is a pipe member (not shown). The other end is connected to the annular oil groove 26 while being connected to the oil supply device.

  A rotary encode 32 is provided at the upper end of the second central shaft 21. The rotary encoder (indexing angle detection means) 32 includes a fixed portion 32a and a rotating portion 32b. The fixed portion 32a is fixed to the upper end of the second central shaft 21, and the rotating portion 32b is a fixing member 33. It is being fixed inside the upper surface of distributor 19 via. A cover 34 is provided outside the upper surface of the distributor 19 so as to cover the rotary encoder 32, and a lid member 35 is provided on the upper surface of the table 13 so as to close the central hole 18 above the cover 34. Yes.

  Accordingly, when the worm 15 of the rotation motor 14 is driven and rotated by the above-described configuration, the worm 15 rolls with a reaction force against the worm wheel 16 while meshing with the worm wheel 16. As a result, the table 13 and the distributor 19 fixed to the table 13 rotate. At this time, a control device (not shown) attached to the rotary table 1 controls the rotation motor 14 and stops the movement at every arrangement interval of the work attached to the table 13, whereby the table 13 can be indexed and rotated. .

  During the indexing operation, the indexing angle of the table 13 is detected as needed by the rotary encoder 32, and the detected indexing angle is fed back to the control device. Further, at the same time as the rotation motor 14 is driven, the oil supply device is also driven, whereby oil is supplied from the oil supply device to the predetermined annular oil groove 26 through the oil supply pipes 27 and 29, and the distributor 19 and the first It flows into the sliding part in contact with the central shaft 20. Next, the oil that has been lubricated and cooled in the sliding portion is supplied to another annular oil groove 26, passes through the oil drain pipes 28 and 30, is returned to the oil supply device, and is circulated again. At this time, the annular oil groove 26 is held in a liquid-tight state by the O-ring 25 to prevent oil leakage.

  Here, during the indexing operation as described above, when the table 13 is indexed and rotated, sliding resistance is generated in the O-ring 25 provided between the rotating distributor 19 and the fixed first central shaft 19. As a result, the first central shaft 19 is twisted. However, since the structure of the present invention has a double structure including the first central shaft 20 for delivering oil and the second central shaft 21 having the rotary encoder 32, the sliding resistance of the O-ring 25 Since the twist is not transmitted to the second central shaft 21, the detection accuracy of the index angle of the table 13 by the rotary encoder 32 is improved. As a result, highly accurate and stable indexing of the rotary table 1 is possible.

  Therefore, according to the rotary table according to the present invention, even if the first central shaft 20 is twisted as the table 13 rotates, the twist is not transmitted to the second central shaft 21, so that it is highly accurate and stable. Indexing can be performed. In addition, the second central shaft 21 is arranged with a gap S in the first central shaft 20 and a rotary encoder 32 is provided at the upper end thereof, while the lower end thereof is connected to the lower end of the first central shaft 20 through the flange portion 21a. By fixing, the support point of the second central shaft 21 is far from the rotary encoder 32, and even if the first central shaft 20 is twisted, the twist is not transmitted to the rotary encoder 32. Index detection accuracy can be improved. Moreover, since the rotary encoder 32 is provided at the upper end of the second central shaft 21, the rotary encoder 32 can be easily inspected and adjusted simply by removing the cover 34 and the lid member 35, and the maintainability is improved. be able to. At this time, since it is not necessary to remove any of the table 13, the distributor 19 constituting the rotary joint 22, the first central shaft 20, and the second central shaft 21, it is possible to eliminate a restoring operation such as an origin adjustment operation. Further, by providing the second central shaft 21 with a fitting portion 21b that fits with the inner peripheral surface of the first central shaft 20, the first central shaft 20 and the second central shaft 21 can be easily centered. And can be arranged concentrically with high accuracy.

  In the present embodiment, the flange portion 20a of the first central shaft 20 is fixed to the bed 12, and the flange portion 21a of the second central shaft 21 is fixed to the lower end of the first central shaft 20, The first central axis 20 and the second central axis 21 may be separately fixed to the bed 12. At this time, it is preferable that the support point of the second central shaft 21 on the bed 21 be as far away from the rotary encoder 32 as possible.

  In addition, while the first central axis 20 and the second central axis 21 are set as the fixed side, the table 13 and the distributor 19 are set as the rotating side, the first central axis 20 and the second central axis 21 are set as the rotating side. On the other hand, the table 13 and the distributor 19 may be fixed. By adopting such a configuration, for example, it can be applied to a turning shaft structure portion of a machine tool such as a multi-axis machine.

  The present invention can be applied to a rotary table that facilitates repair work such as inspection, centering, and positioning of a rotary joint.

It is a sectional side view of the turntable which concerns on one Example of this invention. It is a principal part enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating table 11 Mounting part 12 Bed 13 Table 14 Rotating motor 15 Worm 16 Worm wheel 17,18 Center hole 18a Step part 19 Distributor 20 1st center axis | shaft 20a Flange part 21 2nd center axis | shaft 21a Flange part 22b Fitting part 22 Rotary joint 23 Mounting plate 24 Bearing 25 O-ring 26 Annular oil grooves 27 and 29 Oil supply pipes 28 and 30 Oil discharge pipe 32 Rotary encoder 32a Fixing part 32b Rotating part 33 Fixing member 34 Cover 35 Cover member

Claims (3)

Bed and
A table rotatably supported by the bed;
A rotary joint disposed coaxially with the rotation axis of the table;
The rotary joint is
A distributor having a supply and discharge pipe for supplying and discharging fluid to and from the table and rotating integrally with the table;
A first central axis that has a supply / discharge pipe communicating with the supply / discharge pipe of the distributor and is fixed to the bed;
A rotary table having indexing angle detecting means for detecting an indexing angle of the table and a second central axis fixed to the bed. The rotary table according to claim 1, wherein
Fixing one end of the first central axis to the bed;
Arranging the second central axis with a gap in the first central axis;
A rotary table characterized in that the index angle detecting means is provided at one end of the second central axis, and the other end of the second central axis is fixed to one end of the first central axis. The rotary table according to claim 2,
A turntable having a fitting portion that is fitted to the inner peripheral surface of the first central axis is provided on the other end side of the second central axis.

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