JP2642415B2 - Rotary table device - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to a rotary table device suitable for being incorporated in a semiconductor manufacturing device, an ultra-precision processing device, or the like.

(Prior Art) As is well known, when manufacturing a semiconductor device, it is necessary to provide a rotary table device capable of positioning a rotational direction position with high accuracy while holding a semiconductor wafer. Although various types of such rotary table devices are considered, when classified according to the driving source for positioning, they are classified into those using a piezoelectric element and those using a motor represented by a step motor.

FIG. 6 shows a typical example in which a piezoelectric element is used as a drive source. A spring is provided between a peripheral portion of a turntable 2 and a stationary portion 3 which are rotatably provided about a rotation center line 1. 4, a piezoelectric element 6 is interposed between a protruding portion 5 provided on the peripheral edge of the turntable 2 and the stationary portion 3, and the position of the turntable 2 in the rotational direction is adjusted by expanding and contracting the piezoelectric element 6. Controlling.

However, in the rotary table device configured as described above, the stroke obtained by the piezoelectric element 6 is generally several tens of strokes.
Since it is as small as μm or less, it is necessary to provide a separate table for coarse adjustment. For this reason, there was a problem that it was difficult to use.

On the other hand, FIG. 7 shows a typical example using a motor as a drive source. In the vicinity of a rotary table 12 rotatably provided about a rotation center line 11, a feed screw 13 and a non- A ball screw 15 consisting of a nut 14 mounted in a rotating state is arranged in the rotational tangential direction of the rotary table 12, and both ends of a feed screw 13 are rotatably supported by bearings 16 and 17, and the feed screw 13 is coupled to a coupling 18, It is connected to the rotating shaft of a motor 20 via a speed reducer 19 which is advantageous for improving the positioning accuracy. Then, a presser 21 is provided on the nut 14, and this presser
At 21, a pressing force in the rotational tangential direction is applied to a protrusion 22 provided on the peripheral portion of the rotary table 12, and a force in the direction opposite to the pressing force is applied to the rotary table 12 by a spring 23. Therefore, in the rotary table device configured as described above, the rotational direction position of the rotary table 12 can be controlled over a wide range by selecting the rotation direction and the rotation angle of the motor 20.

However, in the rotary table device configured as described above, the backlash existing in the speed reducer 19 constituted by a combination of gears and the axial play existing in the ball screw 15 are caused by the rotational positioning accuracy. And high drive resolution cannot be obtained. The reduction gear can be omitted by using a motor that generates a large torque, and the effect of backlash can be eliminated. However, in this case, a large motor must be incorporated, so that the size of the entire device can be reduced. Becomes difficult. Further, even in this case, the influence of the backlash in the axial direction of the ball screw 15 cannot be eliminated.

(Problems to be Solved by the Invention) As described above, in the conventional rotary table apparatus, if a piezoelectric element is used as a driving source for positioning, a table for coarse adjustment must be facilitated separately. In addition, in the case of using a motor as a drive source, the position in the rotation direction can be controlled over a wide range. On the other hand, high-precision positioning is achieved due to the backlash in the reduction gear and the play in the direction change mechanism. There was a problem that could not be done.

Therefore, the present invention can minimize the effects of backlash and backlash of the direction changing mechanism without incurring a complicated configuration and an overall increase in size, and achieve high precision over a wide angle range. It is an object of the present invention to provide a rotary table device capable of performing positioning.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the turntable device according to the present invention, a turning force applying means for applying a force for rotating the turntable in one direction, A pressure receiving portion provided on a peripheral portion of the rotary table, a block having a flat receiving surface for contacting the pressure receiving portion and preventing rotation of the rotary table in one direction, and a non-parallel to the block receiving surface. And a support mechanism for movably supporting the rotary table in a direction non-parallel to the rotation center line of the rotary table, and a drive mechanism for moving the block via the support mechanism.

Further, in the rotary table device according to the present invention, a receiving surface portion provided on a peripheral portion of the rotary table and having a flat receiving surface, and prevents rotation of the rotary table in one direction by contacting the receiving surface portion. A pressing portion, and the pressing portion is movably supported by the support mechanism in a direction non-parallel to the receiving surface and in a direction non-parallel to a rotation center line of the rotary table.

When the pressure receiving portion or the pressing portion is constituted by a bearing mounted with the rotation center line orthogonal to the moving direction of the support mechanism, the friction between the block and the receiving surface portion can be effectively reduced. .

(Operation) According to the first aspect, a block having a flat receiving surface that contacts the pressure receiving portion and prevents rotation of the rotary table in one direction is not separated from the receiving surface by the support mechanism. It is provided movably in a direction that is parallel and non-parallel to the rotation center line of the rotary table. Claim 2
In the device described in (1), the pressing portion that contacts the receiving surface portion having the flat receiving surface to prevent rotation of the rotary table in one direction is not parallel to the receiving surface by the support mechanism, and Are provided so as to be movable in a direction non-parallel to the rotation center line. Therefore, the receiving surface of the block or the receiving surface portion functions as a wedge action surface, and the block or the receiving surface portion performs exactly the same function as the speed reducer. To improve the positioning accuracy, it is desirable to obtain a large reduction ratio. The speed reduction ratio of the block or receiving surface is
It depends on the angle between the moving direction of the block or the pressing portion and the receiving surface, and it is easy to make the reduction ratio sufficiently large. In this case, since no gear is used, no backlash exists. Therefore, the drive of a small motor etc. is reduced, and it is not affected by backlash.
In addition, since positioning can be performed with a large reduction ratio, positioning accuracy can be greatly improved. Further, when the block or the pressing portion is attached to a direction conversion mechanism, for example, a nut of a ball screw, a force applied from the rotary table side via the receiving surface or the pressing portion is applied to the nut in the radial direction. This force reduces the axial play between the feed screw and the nut. Therefore, a decrease in positioning accuracy due to backlash can be suppressed.

(Example) Hereinafter, an example is described with reference to drawings.

FIG. 1 shows an external view of a rotary table device 30 according to one embodiment.

The turntable device 30 includes a base 31 having a flat upper surface. A rotary table 32 is rotatably arranged at the center of the upper surface of the base 31. The rotary table 32 is formed such that one side forms a part of a circular plate with the rotation center 33 as a boundary, and the other side is formed in a simple flat plate shape. As shown in FIG. 3, a shaft 34 protrudes from the lower surface of the turntable 32 concentrically with the rotation center line, and the shaft 34 is inserted into a hole 35 provided in the base 31. A bearing 36 is pressurized between the inner surface of the hole 35 and the outer surface of the shaft 34 so as to eliminate backlash in the radial direction.
Is installed.

A pressure receiving portion 37 is formed at one corner of the turntable 32. As shown in FIG. 3, the pressure receiving portion 37 has a cavity 38 formed on one side surface of one corner portion so as to extend horizontally inward from the side surface by a predetermined depth, and
A shaft 39 is provided so as to traverse the vertical direction of the rotary table 32 and is parallel to the rotation center line of the rotary table 32. And a deep groove ball bearing 42 mounted as described above.

On the base 31, an electromagnetic actuator, that is, an electromagnetic solenoid 43, in which a plunger is in contact with the side surface of the other corner of the rotary table 32 and always applies a counterclockwise rotational force to the rotary table 32, is arranged. .

On the other hand, at a position corresponding to the electromagnetic solenoid 43 with the rotary table 32 interposed therebetween, a flat receiving surface 44 is provided which contacts the outer ring 41 of the deep groove ball bearing 42 to prevent the rotary table 32 from rotating counterclockwise. Block 45 is arranged. Receiving surface 44
As shown in FIG. 2, the contact surface with the outer ring 41 is
And extends along the upper surface at right angles to the upper surface. That is, in this example, it extends from the bottom to the top in FIG.

The block 45 is fixed to a nut 47 of a ball screw 46. The feed screw 48 of the ball screw 46 is arranged such that its axis is parallel to the upper surface of the base 31 and is not parallel to the direction in which the receiving surface 44 extends. Both ends of the feed screw 48 are supported by bearings 49 and 50 whose pressurization is controlled so that no backlash occurs in the radial direction.
One end of the feed screw 48 is connected to the base via the coupling 51.
A motor, such as a step motor, fixed on 31
It is connected to 52 rotating shafts. The nut 47 is not rotated by the linear guide mechanism 53. Further, the feed screw 48 is supported so as to be linearly movable in the axial direction.

With such a configuration, the rotational position of the rotary table 32 is always determined by the contact position of the outer ring 41 on the receiving surface 44 provided on the block 45. That is, the plunger of the electromagnetic solenoid 43 always elastically applies a counterclockwise rotational force to the rotary table 32. On the other hand, the receiving surface 44 of the block 45 prevents the turntable 32 from rotating counterclockwise through the outer ring 41. The direction in which the receiving surface 44 extends is
The moving direction of the nut 47 in the ball screw 46 is in a non-parallel state. Therefore, when the motor 52 is driven in one direction to move the nut 47 upward by a predetermined amount in FIG. 2, the turntable 32 rotates counterclockwise by a certain amount and stops. Conversely, when the motor 52 is driven in the other direction to move the nut 47 downward by a certain amount in FIG. 2, the turntable 32 rotates clockwise and stops. The amount of movement of the nut 47 and the amount of rotation of the turntable 32 are 1
Rather than one, it is determined by the angle between the direction in which the receiving surface 44 extends and the direction in which the nut 47 moves linearly. That is, the block 45 exerts a wedge action, and performs exactly the same function as the speed reducer. The speed reduction ratio of the block 45 increases as the angle decreases.

As described above, a so-called speed reducer utilizing a wedge action is used without using a speed reducer configured by a combination of gears. Therefore, there is no backlash.
Moreover, it is easy to make the reduction ratio sufficiently large. For this reason, a small motor can be used and the rotational positioning accuracy can be improved. Most of the force applied to the receiving surface 44 is applied to the nut 47 as a radial force. As a result, the play in the axial direction between the feed screw 48 and the nut 47 is also reduced. Therefore, a decrease in positioning accuracy due to the backlash in the axial direction of the ball screw 46 is also suppressed.

In the above-described embodiment, an electromagnetic solenoid is used as a means for constantly applying one-way rotational force to the rotary table 32 as an elastic force.
Although 43 is used, it may be provided by a spring or a plunger. In addition, the rotary table 32 and the block 45
May be made of a member having high wear resistance, the corner of the rotary table 32 may be directly contacted with the receiving surface 44 of the block 45 without using a deep groove ball bearing. Further, the linear guide mechanism may be provided at a position facing the block 45 with the nut 47 interposed therebetween. Also, the motor
A drive mechanism such as an air cylinder may be used instead of 52.

In the above embodiment, the rotary table 32 is provided with the pressure receiving portion 37, and the pressure receiving portion 37 is provided with the receiving surface 44 of the block 45.
Are in contact with, but not limited to. That is, as shown in FIG. 4, a rotary table 32 is provided with a block 45 having a receiving surface, a nut 47 is provided with a deep groove ball bearing 42 as a pressing portion, and the outer ring 41 of the deep groove ball bearing 42 is The arrangement may be reversed from that of FIG. 1 so as to make contact with the receiving surface. Also, as shown in FIG. 5, a linear guide mechanism 53 that is used as a receiving surface portion having a receiving surface 44 and that moves in a direction non-parallel to the receiving surface 44 is disposed on the nut 47, as shown in FIG. Deep groove ball bearings 42 mounted as pressure members
May be brought into contact with the receiving surface 44.

[Effects of the Invention] As described above, according to the present invention, high-precision rotational positioning can be realized without being affected by backlash or backlash of the direction changing mechanism during positioning.

[Brief description of the drawings]

FIG. 1 is an external view of a rotary table device according to one embodiment, FIG. 2 is a top view of the device, and FIG. 3 is AA in FIG.
FIGS. 4 and 5 are top views showing modified examples of the turntable device of the present invention, respectively, and FIGS. 6 and 7 are schematic structural views of a conventional turntable device. 31… Base, 32… Rotary table, 36… Bearing, 37…
Pressure receiving part, 41 ... Outer ring (pressing part), 42 ... Deep groove ball bearing, 43 ...
… Electromagnetic solenoid (rotational force applying means), 44 …… Receiving surface, 45
…… Block (receiving surface part), 46 …… Ball screw, 52 …… Step motor, 53 …… Linear guide mechanism.

Claims (3)

(57) [Claims] A rotating table rotatably arranged; rotating force applying means for applying a force to rotate the rotating table in one direction; a pressure receiving portion provided on a peripheral portion of the rotating table; A block having a flat receiving surface for contacting the pressure receiving portion and preventing rotation of the rotary table in one direction; and disposing the block non-parallel to the receiving surface and a rotation center line of the rotary table. A support mechanism for movably supporting the block in a non-parallel direction, and a drive mechanism for moving the block via the support mechanism. 2. A rotary table which is rotatably arranged, a rotational force applying means for applying a force to rotate the rotary table in one direction, and a flat receiving surface provided on a peripheral portion of the rotary table. A receiving surface portion, a pressing portion that contacts the receiving surface portion to prevent rotation of the rotary table in one direction, and that the pressing portion is non-parallel to the receiving surface and is aligned with a rotation center line of the rotary table. A rotary table device, comprising: a support mechanism for movably supporting a non-parallel direction with respect to the support mechanism; and a drive mechanism for moving the pressing portion via the support mechanism. 3. The rotary table device according to claim 1, wherein the pressure receiving portion or the pressing portion is constituted by a bearing mounted with a rotation center line orthogonal to a moving direction of the support mechanism.