JP2005028539A - Rotary table device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary table formed with a balance cylinder so as to form no interference area with a cutting tool, the balance cylinder negating a rotational moment generated when an unbalance load eccentrically mounted around the horizontal axis is rotated around the axis. <P>SOLUTION: This rotary table device, which is provided with a balance cylinder 29 for canceling a rotational moment generated as a result of rotation of a mounted unbalance load 31 around the horizontal axis X, includes a cylinder body 34 which is rotatably mounted around the horizontal axis Y at a position eccentric from the horizontal axis X with a crank member 37 rotating together with a rotating shaft 19 and the front end of a rod 35 is journaled to a base 4 side rotatably around a horizontal axis Z. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotary table device mounted on a table of a machine tool such as a machining center.

Conventionally, in a machine tool such as a machining center, a rotary table device is placed and fixed on a table of the machine tool, a workpiece is attached to the rotary table provided in the rotary table device, and the workpiece is cut with a cutting tool while rotating the workpiece. Had gone. Such a rotary table is often used with a rotary axis that is vertical or horizontal, and rotates according to a program preset in the machine tool to index the workpiece.
When performing more complicated workpiece machining, an inclined rotary table device in which the rotation axis of the rotary table to which the workpiece is attached is inclined as described in Patent Document 1.

In this tilt type rotary table device, a pair of support devices including a rotary table are arranged on a work table so that the rotary table faces each other, and a work rotary table is interposed between the pair of rotary tables via an eccentric jig. Is provided.
The eccentric jig is a concave in a front view having a bottom portion facing in the horizontal direction and a bracket portion erected from both edges thereof, and a work rotary table is provided at the center of the bottom portion.
Since the tip of the bracket is attached to the rotary table of the support device, rotating the rotary table causes the bracket to rotate integrally around the horizontal axis, and the bottom of the eccentric jig is lifted obliquely upward. The rotary shaft of the rotary table for use had a predetermined oblique angle.

As described above, the eccentric jig is an unbalanced load in which a large rotational moment is generated around the coaxial axis when rotating around the horizontal axis because the center of gravity is greatly decentered from the horizontal axis. It was a factor that hindered proper indexing rotation.
In the technique described in Patent Document 1, in order to cancel the rotational moment, a balance cylinder is provided on one side of the support device, and the rod tip of the balance cylinder is eccentric to the rotation shaft of the support device, that is, the rotary table. It was to be linked. Further, the cylinder body of the balance cylinder is pivotally supported by the support case of the support device.
Japanese Utility Model Publication No. Hei 6-3531 (Pages 4-5, FIG. 3)

The cylinder body of Patent Document 1 described above is provided so as to protrude from the outside of the support device in a side view, and the cutting tool and the cylinder body come into contact with each other when the cutting tool or the like enters the protruding region. It was.
In Patent Document 1, in order to reduce such interference, the cylinder body is attached obliquely in a side view, but the interference area is not greatly reduced. In addition, the movement of the rod is limited to the rotation shaft, and it has been impossible to rotate the rotary table by 360 degrees.

  Therefore, in view of the above problems, the present invention provides a balance cylinder for canceling a rotational moment generated when an unbalanced load eccentrically mounted about a horizontal axis is rotated about a coaxial axis, and an interference with a cutting tool. It is an object of the present invention to provide a turntable device attached so that there is no area.

In order to achieve the above object, the present invention takes the following technical means.
That is, technical means for solving the problems in the present invention include a support frame mounted on a base, a rotary shaft supported on the support frame so as to be rotatable about a horizontal axis, and a rotary shaft provided on the rotary shaft. A rotary table device provided with a balance cylinder on the rotary shaft so as to cancel a rotational moment generated when an unbalanced load attached to the rotary table rotates around the horizontal axis. The balance cylinder includes a cylinder body and a rod that can be expanded and contracted with respect to the cylinder body, and the cylinder body is a crank member that rotates integrally with the rotating shaft, and the horizontal axis core is located at a position eccentric from the horizontal axis core. The tip of the rod is provided on the base side in a horizontal direction parallel to the horizontal axis. Characterized in that it is rotatably pivoted around.

According to this technical means, the cylinder main body is rotatably provided on the crank member that rotates integrally with the rotary shaft, and the rod is pivotally supported on the base side so that the unbalanced load is reduced. The rotation around the horizontal axis causes the balance cylinder to perform a crank motion with the tip of the rod as a fulcrum. During this crank motion, the balance cylinder generates a rotation moment (reverse rotation moment) due to the drag force of the rod expansion and contraction, and can cancel the rotation moment due to the unbalance load.
In addition, since the cylinder body is attached to a crank member provided so as to be rotatable integrally with the rotary table, the cylinder body does not protrude largely outward from the rotary table device, thereby preventing interference with contact with a cutting tool or the like. It becomes possible.

  Further, technical means for solving the problems in the present invention include a support frame attached on the base, a rotary shaft supported on the support frame so as to be rotatable around a horizontal axis, and provided on the rotary shaft. A pair of support devices provided with the rotary table, the pair of support devices are arranged so that the rotary tables face each other, and an unbalanced load that rotates integrally with the rotary table is provided between the rotary tables, and at least In a rotary table device in which a balance cylinder is provided on the rotary shaft of one support device in order to cancel the rotational moment generated when the unbalanced load rotates about the horizontal axis, the balance cylinder is connected to the cylinder body. A rod that is extendable and contractable with respect to the cylinder body, and the cylinder body is a clamp that rotates integrally with the rotating shaft. A member is provided at a position eccentric from the horizontal axis so as to be rotatable about a horizontal axis parallel to the horizontal axis, and the tip of the rod is on the base side around the horizontal axis parallel to the horizontal axis. It is characterized in that it is pivotally supported by the shaft.

According to this technical means, the cylinder main body is rotatably provided on the crank member that rotates integrally with the rotary shaft, and the rod is pivotally supported on the base side so that the unbalanced load is reduced. The rotation around the horizontal axis causes the balance cylinder to perform a crank motion with the tip of the rod as a fulcrum. During this crank motion, the balance cylinder generates a rotation moment (reverse rotation moment) due to the drag force of the rod expansion and contraction, and can cancel the rotation moment due to the unbalance load.
In addition, since the cylinder body is attached to a crank member provided so as to be rotatable integrally with the rotary table, the cylinder body does not protrude largely outward from the rotary table device, thereby preventing interference with contact with a cutting tool or the like. It becomes possible.

The technical means for solving the problems in the present invention is characterized in that the base is a table of a machine tool, and the tip of the rod is pivotally supported by the table.
According to this technical means, the rod tip is pivotally supported by the table of the machine tool, so that the rod of the balance cylinder does not protrude greatly from the rotary table device in a side view, and a cutting tool, etc. It is possible to prevent interference that comes into contact with the device.
The technical means for solving the problems in the present invention is characterized in that the eccentric direction of the cylinder body with respect to the rotational axis of the rotary table is the same as the eccentric direction of the unbalanced load.

According to this technical means, the reverse rotational moment by the balance cylinder can be maximized while the rotational moment due to the unbalanced load is maximized.
Further, the technical means for solving the problems in the present invention is that when the unbalance load rotates and is positioned at the uppermost position, the base end of the cylinder body is positioned below the upper end of the unbalance load. It is characterized by.
According to this technical means, even when the unbalance load rotates around the horizontal axis and comes to the top, the base end of the cylinder body does not protrude above the unbalance load, and the cutting tool Etc. can be prevented from contacting the base end of the cylinder body.

The technical means for solving the problems in the present invention is characterized by comprising control means for controlling the balance cylinder so that the drag force when the rod retracts to the cylinder body is constant.
According to this technical means, it becomes possible to efficiently cancel the rotational moment due to the unbalanced load by making the drag force of the rod constant by the control means.
The technical means for solving the problems in the present invention is characterized in that the working medium of the balance cylinder is air or oil, and the control means is a regulator capable of controlling the working medium.

  According to this technical means, it is possible to use an inexpensive or simple air or hydraulic cylinder as a balance cylinder, and the control can be easily performed by a regulator.

  According to the present invention, in the rotary table device, the balance cylinder for canceling the rotational moment around the coaxial core due to the unbalanced load attached eccentrically around the horizontal axis is provided so that there is no interference area with the cutting tool. It can be attached.

Hereinafter, a first embodiment of a rotary table device according to the present invention will be described by exemplifying an inclined rotary table device attached to a machining center.
A machining center is an NC (Numerical Control) machine tool that automatically performs various operations such as milling, drilling, and boring, and is equipped with an automatic cutting tool replacement function and an automatic machining function for two or more surfaces of a workpiece. It is a thing.
FIG. 1 shows a part of a horizontal machining center 1, that is, a horizontal machine spindle 2 and a cutting tool 3, a table 4 for fixing a work 6, and an inclined rotary table device 5 mounted and fixed on the table 4. Has been.

In the description below, the left-right direction (horizontal direction) refers to the x-axis direction in FIG. 1, the front-rear direction refers to the y-axis direction, and the up-down direction refers to the z-axis direction.
The tilt-type rotary table device 5 includes a work rotary table 7 to which the work 6 is attached, and the rotary shaft 19 of the work rotary table 7 can be tilted, so that the complex work 6 can be processed. Is.
The inclined rotary table device 5 includes a pair of support devices 12 and 27 each having a rotary table that rotates about a horizontal axis X, and the support devices 12 and 27 are attached so that the rotary tables face each other. It is arranged on a table (base) 4 of the machine tool 1 via a table 10.

One of the support devices is a rotary table device 12 having a drive motor 11 such as a servomotor, and the drive motor 11 can rotate the rotary table 8 by a predetermined angle.
Specifically, a mounting base 10 is placed on the table 4 of the machine tool 1, and is fitted into a fixture 15 that penetrates the mounting base 10 and a rail groove 16 formed on the table 4 in the left-right direction. As the slider 17 is engaged, the table 4 and the mounting base 10 are integrated. Further, the lower part of the support frame 18 of the rotary table device 12 is placed on the upper part of the mounting base 10 and is fixed by a fixing tool 15 such as a bolt.

With this mounting base 10, the rotary table device 12 is disposed above the table 4, and a sufficient space can be secured between the axis X of the rotary shaft 19 of the rotary table 8 and the table 4. It is possible to attach jigs and workpieces.
The support frame 18 of the rotary table device 12 is rotatably supported by bearings and the like so that the rotary shaft 19 faces the horizontal axis X, and a worm wheel 20 is provided in the middle of the rotary shaft 19. It has been. A worm screw 21 is provided on the rotary shaft 19 of the drive motor 11 provided in the rotary table device 12, and the worm screw 21 and the worm wheel 20 are engaged with each other.

A disc-shaped rotary table 8 is coaxially provided on the side (base end) of the rotary shaft 19 that faces the other support device 27, and a work 6, a jig, or the like is provided on the mounting surface 22. In order to enable attachment, a radially extending guide groove 23 is formed.
Due to the rotation of the drive motor 11, the rotary table 8 is rotated by a predetermined angle so that the workpiece 6 and the like can be indexed.
The other support device is a support table device 27 in which a support table 26 having substantially the same shape as the rotary table 8 is provided in a rotation-free state, and does not have the drive motor 11 or the like.

Specifically, a mounting base 10 is placed on the table 4 of the machine tool 1, a fixture 15 that passes through the mounting base 10, and a slider 17 that fits in a rail groove 16 formed on the table 4. And the table 4 and the mounting base 10 are integrated. Further, the lower part of the support frame 18 of the support table device 27 is placed on the upper part of the mounting base 10 and is fixed with a fixture 15 such as a bolt.
A rotating shaft 19 is supported on the support frame 18 of the support table device 27 via a bearing or the like so as to be rotatable coaxially with the horizontal axis X, and the side of the rotating shaft 19 facing the rotating table device 12 (base end). Is provided with a coaxial and disk-shaped support table 26. The mounting surface 22 is formed with radially extending guide grooves 23 so that the workpiece 6 and jigs can be mounted.

The distal end side of the rotating shaft 19 protrudes outward in the left-right direction of the support table device 27 and is connected to a balance cylinder 29 described later.
An eccentric jig 31 is provided between the rotary table 8 and the support table 26 so as to rotate integrally.
The eccentric jig 31 has a bottom portion 32 that faces in the horizontal direction and a bracket portion 33 erected from both edge portions of the bottom portion 32, so that the eccentric jig 31 is concave in a front view, and the bracket portion 33 protrudes substantially at the center of the bottom portion 32. On the side, a work rotary table 7 having a rotary shaft 19 perpendicular to the bottom 32 is provided. The work rotary table 7 is rotated by a predetermined angle by a hydraulic pressure supplied from the outside or a driving force of the provided drive motor 11 or the like, so that the attached work 6 can be indexed.

The distal end portion of the bracket portion 33 is attached to the rotary table 8 and the support table 26 with a fixture 15. Therefore, by driving the drive motor 11 of the rotary table device 12 and rotating the rotary table 8, the bracket portion 33 of the eccentric jig 31 also rotates integrally around the horizontal axis X, and the bottom 32 of the eccentric jig 31 is The rotary shaft 19 of the work rotary table 7 has a predetermined oblique angle.
However, when the eccentric jig 31 is rotated around the horizontal axis X, a strong rotational moment Mj due to the eccentricity is generated, making it impossible to rotate smoothly and driving motor 11. The need to have a large horsepower arises.

As a countermeasure, in the case of this embodiment, a balance cylinder 29 that generates a reverse rotation moment M against the rotation moment Mj is provided on the outer side in the left-right direction of the support table device 27 (on the counter-rotation table device 12 side). .
As shown in FIGS. 2 and 3, the balance cylinder 29 is a fluid cylinder that uses air or oil as a working medium, and includes a cylinder body 34 and a rod 35 that can be moved out and withdrawn from the cylinder body 34. .
The rod 35 is retracted and contracted in the cylinder body 34 by applying a predetermined drag force F. In this embodiment, the rod 35 operates in the cylinder body 34 in order to keep the drag force F constant. Control means 36 (regulator) for adjusting the pressure of the medium is provided outside.

A base end of a crank member 37 facing outward in the horizontal axis X direction is attached to the rotary shaft 19 projecting outward from the side surface of the support frame 18 of the support table device 27, and a cylinder main body is attached to the distal end thereof. 34, a cylinder body middle portion is rotatably attached around a horizontal axis Y parallel to the horizontal axis X via an attachment member 38 provided so as to surround the middle portion 34.
The crank member 37 is such that the distance between the pivot axis X and the pivot axis Y of the cylinder body 34 is e.

On the other hand, a connecting member 39 having a bifurcated shape is attached to the tip of the rod 35 of the balance cylinder 29, and a rod support member 40 attached to the table 4 of the machine tool 1 between the two forks of the connecting member 39. The vertical portion 41 enters and is pivotally supported by a pivot pin 43.
The rod support member 40 is L-shaped in a front view having the vertical portion 41 and a horizontal portion 42 extending to one side from below, and the rail portion 16 formed in the table 4 is formed in the horizontal portion 42. It is fixed to the main body of the table 4 via. Since the rod support member 40 is fixed via the rail groove 16, the position of the rod support member 40 can be changed in the rail groove 16 direction (left-right direction).

As described above, the tip of the rod 35 is pivotally supported on the table 4 side of the machine tool 1, and the middle portion of the cylinder body 34 is connected to the rotary shaft 19 of the support table device 27 via the crank member 37 at an eccentric distance e. Therefore, as shown by a two-dot chain line in FIG. 3, the eccentric jig 31 rotates, that is, the rotating shaft 19 rotates, so that the balance cylinder 29 is separated from the rotating shaft 19 by a distance L. 35 Crank motion centered on the tip.
Further, the cylinder body 34 is positioned on the outer side of the rotating shaft 19 of the support table device 27 in the left-right direction, and the rod 35 is positioned on the outer side of the mounting base 10 in the left-right direction. It will not project significantly in the direction. Therefore, the interference area in contact with the cutting tool 3 or the like is small, and contact with the cutting tool 3 or the like can be prevented.

Next, the operation of the balance cylinder 29 will be described.
As shown in FIG. 4, when the eccentric jig 31 is rotated about the horizontal axis X in the direction of arrow A in order to incline the rotary shaft 19 of the work rotary table 7, the rotary shaft 19 of the support table device 27 is also moved. The crank member 37 that is rotated and connected is also cranked.
That is, the cylinder body 34 facing in the vertical direction as shown in (a) rises in conjunction with the crank member 37 as the eccentric jig 31 rotates and lifts in the direction of arrow A, and the cylinder body as shown in (b). In a state where the rod 35 protrudes from 34, it turns to the upper left. Thereafter, as shown in (c), the cylinder body 34 is positioned substantially vertically and upward. At this time, the balance cylinder 29 is arranged with respect to the rotary shaft 19 so that the base end (on the opposite rod side) of the cylinder body 34 does not protrude upward from the uppermost edge of the eccentric jig 31.

Further, when the eccentric jig rotates in the direction of arrow A, the cylinder main body 34 faces obliquely upward to the right as shown in (d), and the rod 35 is stored in the cylinder main body 34 and returns to the state of (a). become.
In the process of performing such movement, the balance cylinder 29 cancels out the rotation moment Mj around the rotation axis 19 of the eccentric jig 31 with the rotation moment M generated by the drag F when the rod 35 is pushed into the cylinder body 34. Will play a role.
The rotational moment Mj and the reverse rotational moment M will be described in detail by exemplifying a state where the eccentric jig 31 is located obliquely to the left in a side view as shown in FIG.

In this figure, the support table 26 is rotated by an angle θ, and the eccentric jig 31 is lifted to the front side by θ. At this time, the rotational moment Mj around the horizontal axis X due to the weight of the eccentric jig 31 is Mj = Fj · e. Fj is a force that the eccentric jig 31 tries to return to the original position by its own weight.
At this time, a drag force F against the reduction of the rod 35 is generated in the balance cylinder 29, and the reverse rotation moment M generated by this force F is M = F · cos α · e.
Where α is
α = 180 ° −90 ° −θ−β,
β = tan ⁻¹ ((e · sin θ) / (L−e · cos θ))
Calculated by

The reverse rotational moment M cancels the rotational moment Mj and reduces the unbalanced load caused by the eccentric jig 31. Since the eccentric jig 31 can be smoothly rotated when the drag F of the rod 35 is constant, the air in the cylinder body 34 is controlled by a regulator which is a cylinder control means 36 provided in the balance cylinder 29. The pressure is kept constant.
FIG. 6 shows the rotational moment Mj (one-dot chain line) generated when the eccentric jig 31 according to the present embodiment is rotated, the reverse rotational moment M (solid line) generated by the balance cylinder 29, and the moment deviation (2). An example of a dotted line) is shown.

As the support table 26 rotates, the rotational moment Mj due to the eccentric jig 31 gradually increases and becomes maximum at a rotation angle of 90 degrees. This rotational moment Mj becomes a large load on the drive system 45 such as the drive motor 11 and the worm screw 21.
On the other hand, the reverse rotation moment M by the balance cylinder 29 is generated as shown by a solid line so as to cancel it, and the rotation moment acting on the drive system 45 becomes like a two-dot chain line by canceling both. .
Therefore, it is possible to realize a compact and inexpensive tilt-type rotary table device 5 without requiring a drive motor 11 having a larger horsepower than necessary.

In the example illustrated in FIG. 6, the positions of the maximum values of the rotational moment Mj and the reverse rotational moment M do not coincide with each other, but the protrusion of the crank member 37 with respect to the axis of the rotary table 8 so as to coincide with each other. By making the direction and the eccentric direction of the unbalanced load 31 substantially the same direction, the rotational moment can be eliminated more reliably.
As described above, the operation of the balance cylinder 29 has been described focusing on the rotational moment M and the reverse rotational moment Mj. However, considering the drag F and the force Fj caused by the eccentric jig 31, the balance cylinder 29 is operated so that they are always balanced. There is no problem even if you think about it.

A second embodiment of the gripping device according to the present invention will be described below.
As shown in FIGS. 7 and 8, the support table device 27 of the second embodiment is wider than the support frame 18 main body in a side view at a lower portion of a mounting member 38 to which the device 27 is attached, and in a front view. The support table device has a bowl-shaped mounting portion 46 that protrudes outward in the left-right direction, and the mounting portion 46 is mounted on the table 4 and fixed to the rail groove 16 with a fixing jig. 27 is attached to the table 4 of the machine tool 1.
Further, the connecting member 39 at the distal end of the rod 35 is fitted into the rod support member 40 provided in the concave portion 47 at the approximately center in the front-rear direction of the mounting portion 46, and is attached to the rotational axis X of the support table 26 by the pivot pin 43. It is pivotally supported around a parallel horizontal axis Z.

Thus, as in the first embodiment, after the support table device 27 is arranged on the table 4, the complicated work of fixing the rod 35 of the balance cylinder 29 to the table 4 side while aligning is omitted. Will be able to.
Other configurations are substantially the same as those of the first embodiment, and the operational effects are also substantially the same.
A third embodiment of the gripping device according to the present invention will be described below.
As shown in FIG. 9, in the third embodiment, a rotary table device 12 having a rotary table 8 that rotates around a horizontal axis X is arranged on the table 4, and the rotary table 8 is arranged around the horizontal axis X. An eccentric workpiece 6 (object to be processed) is attached in a cantilever manner. Further, a balance cylinder 29 is provided on the opposite side of the rotary table device 12 from the workpiece 6 in substantially the same manner as in the second embodiment.

As a result, the rotational moment Mj generated when the workpiece 6 is rotated about the horizontal axis X can be resisted by the reverse rotational moment M generated by the balance cylinder 29 and is affected by the unbalance caused by the eccentric workpiece 6 as a whole. The turntable device 12 is difficult.
Other configurations are substantially the same as those of the second embodiment, and the operational effects are also substantially the same.
The gripping device according to the present invention is not limited to the above embodiment.
That is, a horizontal machining center is illustrated as a machine tool, but there is no problem even if it is a vertical machining center or an NC milling machine.

  Further, in the tilt type rotary table device 5 shown in the first or second embodiment, the balance cylinder 29 is attached to the support table device 27 side, but it may be provided on the rotary table device 12 or may be provided on both. There is no problem.

  The present invention can be applied to an indexing table that is attached to a machine tool or the like and performs work indexing.

It is a front perspective view of 1st Embodiment of a rotary table apparatus. It is a front view of the support apparatus provided with the balance cylinder. It is a side view of the support apparatus provided with the balance cylinder. It is an action | operation figure of a balance cylinder. It is the figure which showed the action condition of the reverse rotation moment by a balance cylinder. It is the figure which showed the fluctuation | variation of the rotation moment and reverse rotation moment accompanying the rotation angle of an eccentric jig | tool. It is a front view of the support apparatus provided with the balance cylinder in 2nd Embodiment. It is a side view of the support apparatus provided with the balance cylinder in 2nd Embodiment. It is a front view of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Machine tool 4 Base 8 Rotary table 12 Rotary table apparatus 18 Support frame 19 Rotating shaft 26 Support table 27 Support table apparatus 29 Balance cylinder 31 Eccentric jig (unbalance load)
34 Cylinder body 35 Rod

Claims (7)

A support frame (18) mounted on the base (4), a rotation shaft (19) supported rotatably around the horizontal axis (X) on the support frame (18), and the rotation shaft (19 ) And a rotating table (8) provided on the rotating table (8), and an unbalanced load (31) attached to the rotating table (8) cancels the rotational moment generated by rotating around the horizontal axis (X). Therefore, in the rotary table device provided with the balance cylinder (29) on the rotary shaft (19),
The balance cylinder (29) includes a cylinder body (34) and a rod (35) that can be expanded and contracted with respect to the cylinder body (34), and the cylinder body (34) rotates integrally with the rotating shaft (19). A crank member (37) is provided at a position eccentric from the horizontal axis (X) so as to be rotatable around a horizontal axis (Y) parallel to the horizontal axis (X), and the tip of the rod (35). Is supported on the base (4) side so as to be rotatable about a horizontal axis (Z) parallel to the horizontal axis (X). A support frame (18) mounted on the base (4), a rotation shaft (19) supported rotatably around the horizontal axis (X) on the support frame (18), and the rotation shaft (19 And a pair of support devices (12) and (27) provided with the rotary table (8) provided on the rotary table (8). The pair of support devices (12) and (27) face the rotary tables (8) and (26). An unbalanced load (31) that rotates integrally with the rotary table (8) is provided between the rotary tables (8) and (26), and is provided on the rotary shaft (19) of at least one support device (27). Is a rotary table device provided with a balance cylinder (29) in order to cancel a rotational moment generated when the unbalanced load (31) rotates around a horizontal axis (X).
The balance cylinder (29) includes a cylinder body (34) and a rod (35) that can be expanded and contracted with respect to the cylinder body (34), and the cylinder body (34) rotates integrally with the rotating shaft (19). A crank member (37) is provided at a position eccentric from the horizontal axis (X) so as to be rotatable about a horizontal axis (Y) parallel to the horizontal axis (X). The tip is pivotally supported on the base (4) side so as to be rotatable about a horizontal axis (Z) parallel to the horizontal axis (X).   The rotary table according to claim 1 or 2, wherein the base (4) is a table of the machine tool (1), and a tip of the rod (35) is pivotally supported by the table (4). apparatus.   The eccentric direction of the cylinder body (34) with respect to the rotational axis (X) of the rotary table (8) and the eccentric direction of the unbalanced load (31) are the same. A rotary table device according to claim 1.   The base end of the cylinder body (34) is located below the upper end of the unbalance load (31) when the unbalance load (31) is rotated and positioned at the uppermost position. The turntable apparatus in any one of 1-4.   The control means (36) for controlling the balance cylinder (29) is provided to make the drag force when the rod (35) retracts into the cylinder body (34) constant. The rotary table device according to any one of the above.   The rotary table device according to claim 6, wherein the working medium of the balance cylinder (29) is air or oil, and the control means (36) is a regulator capable of controlling the working medium.

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