JPH10193235A - Angular positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To markedly improve angular positioning accuracy while attaining lightening of weight in small size and capability of stable operation over a long period. SOLUTION: A device comprises a rough angle adjusting means 30 mounting a helical gear 15 in a rotary table 20 and including a worm gear 33 meshed with the helical gear 15, backlash removing means 80 including a driven gear 82 and an energizing means and a fine angle adjusting means 40 including a piezoelectric actuator 41 and a responding movement displacement permitting means 35. The worm gear 33 is rotated with an X axial line serving as the center, through the helical gear 15, the rotary table 20 is rough angle adjusted with a Z axial line serving as the center, also displacement of X axial line direction of the piezoelectric actuator 41 is utilized, and through the worm gear 33 and the helical gear 15, the rotary table 20 is fine angle adjusted. In this way, the rotary table 20 is formed to be capable of executing its angle positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle positioning device for positioning a rotation angle of a rotary table with high accuracy.

[0002]

2. Description of the Related Art An angle positioning device for positioning a rotation angle of a rotary table rotatable about an axis is widely used in various industrial fields.

A conventional angle positioning device is, for example, shown in FIG.
As shown in FIG.
It is mounted rotatably around a bearing (Zp axis) via a bearing 15P, and a reduction gear structure 32P forming an angle adjusting means 30P and a motor 31P are connected to the shaft portion 20PS. Therefore, if the motor 31P is rotated by a predetermined number of rotations (angle), the rotation table 20P can be angularly positioned at a rotation angle of 1 / reduction ratio of the rotation angle.

If the minimum controllable angle of the motor 31P is, for example, 1 degree and the reduction ratio is 1/10, the rotary table 20P can be theoretically positioned at an accuracy of 0.1 degree. it can. However, in practice, the reduction gear structure 32P composed of a gear train has a large backlash (play), so that the accuracy of the angular positioning is, for example, at most 0.5 to 0.2 degrees.

The angular positioning accuracy is such that the value of the rotation angle when the rotary table 20P is actually angularly positioned is the same as the value of the set or instructed rotation angle (a value corresponding to the rotation angle of the motor 31P). It means to become. In other words, it is meaningless if the result of the angular positioning of the rotary table 20P (the detected angle value) happens to be, for example, 0.1 degrees. This is because the angle detection value can be displayed, for example, at 0.01 degrees or less by increasing the resolution by increasing the number of signal divisions of the angle detection means. That is, the angle positioning accuracy of the conventional device is 0.1
The fact that the angle is on the order of degrees can be confirmed from the fact that at least most of the angle detecting means that can be employed in the angle positioning device have a resolution (accuracy) of about 0.1 degrees.

Further, the conventional apparatus (FIG. 13) has a drawback that it is particularly large in height, and it is extremely difficult to dispose the apparatus as a two-stage product on, for example, a table of a positioning apparatus that moves directly on a horizontal axis. Therefore, it cannot meet the demand for smaller and lighter devices that are required for use in, for example, measurement of a far-field image and inspection of a semiconductor pattern.

Thus, as shown in FIG. 14, the present applicant attaches the turntable 20T to the base 10T by Zt (vertical).
The spur gear 15T (tooth 15TG) is integrally attached to the turntable 20T, for example, so as to be rotatable about the axis, and the worm gear 33T (teeth 33TG) is meshed with the spur gear 15T (15TG) and the coupling 32T is connected. By rotating the motor 31T via
The rotary table 20T was formed so as to be able to be positioned at an angle.

According to this, the angle adjusting means 30T (motor 31T, coupling 32T, worm gear 33T).
Can be arranged on the Xt (horizontal) axis orthogonal to the Zt (vertical) axis, which is the rotation center of the turntable 20T, so that a significant reduction in size and weight can be achieved. However, the worm gear 33T (33TG) and the spur gear 15T
(15TG) and the conventional reduction gear structure 32P
Since there is backlash as in the case of (1), it is difficult to improve the angular positioning accuracy.

Here, a rotation supporting bearing 39TB of the worm gear 33T (shaft portion 33TS) was formed to be able to be pressed toward the spur gear 15T by using a tightening screw 89T. That is, by tightening the tightening screw 89T,
Worm gear 33T (33TG) and spur gear 15T (15
TG) and pressed together so that there was no gap (backlash).

By removing the backlash, the motor 3
While the minimum controllable angle of 1T is constant, the angle positioning accuracy of the rotary table 20T is set to, for example, 0.08 to 0.0.
It could be improved up to 5 degrees.

[0011]

However, the worm gear 33T (33TG) and the spur gear 15T (15TG)
In the configuration in which the backlash is removed by strongly tightening the gears, the pitch of each tooth 33TG and 15TG must be finished with high precision and uniformity, which not only causes a great cost increase but also causes a severe operation due to severe wear. Can not. In particular, generation of frictional heat causes deterioration of the angular positioning accuracy. In other words, contradictory results have been brought about as if factors for inferiority of accuracy were included in the high-accuracy measure.

SUMMARY OF THE INVENTION An object of the present invention is to provide an angle positioning device capable of greatly improving the angle positioning accuracy while reducing the size and weight and enabling stable operation for a long period of time.

[0013]

In a device for linearly positioning a linear motion table slidable in the horizontal axis direction in a horizontal axis direction, a nut member on the linear motion table side is spring-mounted with respect to a screw shaft on the base side. If a bias (for example, a tensile force) is applied in one direction (engaging direction) of the horizontal axis, a gap (backlash) between the screw shaft and the nut member can be removed. However, in order to eliminate backlash between the worm gear on the base side and, for example, a spur gear on the rotary table side rotatably held on the base, the angle positioning device employs a method similar to that of the linear motion table. Cannot be introduced. This is because the worm gear and the like make tens to hundreds of rotations each.

In addition, the fact that the worm gear and the table-side spur gear and the like are mechanically and integrally strongly frictionally engaged with each other by using the above-mentioned tightening screws cannot be practically increased in precision from the results of the prototype. is there.

Here, as a result of a number of trial production studies, the worm gear on the base side and the gear on the rotary table side have a low frictional engagement with respect to relative movement (rotation) and can always backlash the two. The mechanism of holding in state was created.

That is, the gear on the rotary table side rotatably mounted on the base side can be rotated by a small external force in a free state. In view of this, the rotary table side gears are helical gears based on the prototype, and the helical gears are biased in a predetermined direction so as to generate a component force in the rotational direction on the tooth inclination (surface) of the helical gears. A driven gear rotatable and rotatable is meshed with the helical gear so that backlash between the helical gear and the worm gear can be removed. Furthermore, assuming that backlash can be removed, the worm gear can be displaced by a small distance in the axial direction, and by using this displacement, the helical gear can be displaced in the tangential direction by the worm gear, that is, it can be rotated by a small angle. It is formed.

That is, according to the first aspect of the present invention, a helical gear is attached to a rotary table rotatable about the Z axis so as to be concentric and synchronously rotatable, and a worm gear rotatable about the X axis is attached to the helical gear. , A driven gear rotatable about the rotation of the helical gear about the Z1 axis and meshed with a driven gear urged in one direction of the Z1 axis or in a direction perpendicular to the Z axis to rotate the worm gear to reduce the coarse angle of the rotary table. The rotary table is formed to be adjustable and the fine angle of the rotary table can be adjusted by slightly displacing the worm gear in the X-axis direction, and the rotary table can be angularly positioned by coarse angle adjustment and fine angle adjustment. .

In this invention, for example, the driven gear urged in one direction of the Z1 axis extending in the vertical direction or in a direction perpendicular to the Z axis pushes the tooth inclination (surface) of the helical gear.
The helical gear is urged in one rotational direction around the Z-axis extending vertically, for example, by the component force in the rotational direction generated thereby, and is constantly in contact with the worm gear. Therefore, if the worm gear is rotated, for example, about the X-axis extending in the horizontal direction, the backlash between the helical gear and the helical gear is removed, so that the rotary table is rotated exactly by the rotation of the worm gear for angular positioning. be able to. Even in the case of the conventional example (for example,
0.5-0.2 degrees) and higher precision (for example, 0.0-0.2 degrees).
5 to 0.03 degrees). Moreover, the driven gear for backlash removal is driven by the rotation of the helical gear,
Low friction and low noise.

Subsequently, the worm gear is slightly displaced (for example, 1 μm) in the X-axis direction using, for example, a piezo actuator.
m). Then, the helical gear meshing with the worm gear is slightly displaced in the tangential direction thereof. As a result, the helical gear has a small angle (for example, 0.002) about the Z axis.
Rotation). That is, fine angle adjustment of the rotary table can be performed.

Accordingly, since the rotary table can be angularly positioned as the sum (or difference) of the coarse angle adjustment amount and the fine angle adjustment amount, the accuracy of the angle positioning can be greatly improved, and the size and weight can be reduced and stable operation can be performed for a long period of time. Can be achieved.

According to a second aspect of the present invention, there is provided a rotary table rotatable about the Z axis, a helical gear mounted concentrically and synchronously rotatable on the rotary table,
Coarse angle adjustment means for rotating a worm gear rotatable about an axis and meshable with a helical gear to adjust a coarse angle of the rotary table; a driven gear meshable with the helical gear and capable of being driven and rotated around the Z1 axis; This driven gear is Z
Backlash removal formed including biasing means capable of biasing in one direction of one axis or in a direction orthogonal to the Z axis, and capable of removing a backlash between the helical gear and the worm gear using the tooth inclination of the helical gear. Means, a piezo actuator displaceable in the X-axis direction and connected to the worm gear so as to be relatively rotatable about the X-axis, and a reaction displacement permitting means for permitting displacement of the worm gear in the X-axis direction in response to the displacement of the piezo actuator. And a fine angle adjusting means for finely adjusting the rotation table via a helical gear by displacing the worm gear in the X-axis direction using the displacement of the piezo actuator.

In this invention, when the worm gear is rotated about, for example, the X-axis extending in the horizontal direction by the coarse angle adjusting means, the helical gear meshing with the worm gear, that is, the rotary table, is rotated, for example, about the Z-axis extending in the vertical direction. The direction can be adjusted by the coarse angle. In this case, since the backlash between the worm gear and the helical gear is removed by the backlash removing means, the coarse angle adjustment is performed in the conventional case (for example, 0.5 to 0.2).
Degree) compared to high accuracy (for example, 0.05 to 0.03).
Degree). In addition, the driven gear forming a part of the backlash means is driven by the rotation of the helical gear, for example, about the Z1 axis extending in the vertical direction, so that there is no problematic frictional heat.

Even when the coarse angle adjustment is completed, the driven gear is urged by the urging means in one direction of the Z1 axis or in a direction orthogonal to the Z axis, so that the toothed inclination (surface) of the helical gear is pushed. . That is, since the teeth of the helical gear are always in contact with the teeth of the worm gear, the backlash is eliminated.

Here, the piezo actuator forming the fine angle adjusting means is slightly displaced in the X-axis direction (for example, 0.
1 μm), the worm gear is slightly displaced in the X-axis direction by the same amount (0.1 μm) by the function of the response displacement permitting means. This minute displacement pushes the helical gear in its tangential direction. At this time, the helical gear is in contact with the worm gear by the backlash removing means, regardless of which direction the worm gear is displaced in the X-axis direction.
Therefore, the helical gear, that is, the rotary table, can be rotated by a small angle (for example, 0.0002 degrees) about the Z axis.

Therefore, since the rotary table can be angularly positioned as the sum (or difference) of the coarse angle adjustment amount and the fine angle adjustment amount, the angle positioning accuracy can be greatly improved, and the rotary table can be reduced in size and weight and stable for a long period of time. Driving can be achieved. In addition, since the piezo actuator and the worm gear are relatively rotatable about the X axis, coarse angle adjustment and fine angle adjustment can be performed simultaneously.
Angle adjustment can be performed more quickly.

The invention according to claim 3 is characterized in that the Z axis extends in the vertical direction and the X axis extends in the horizontal direction, and the Z1 axis extends in the vertical direction in parallel with the Z axis. It is a positioning device.

In this invention, the rotary table to which the helical gear is mounted is rotatable about the vertical Z axis, and the worm gear meshing with the helical gear is mounted rotatably about the horizontal X axis. At the same time, the driven gear is mounted so as to be driven to rotate about a Z1 axis parallel to the Z axis. Therefore, in addition to providing the same operation and effect as the case of the second aspect of the present invention, it is possible to achieve a significant reduction in size and weight, particularly the height, and the structure is simple.

Further, the invention according to claim 4 is characterized in that the reaction displacement permitting means is mounted between a shaft of a motor for applying a rotational force to the worm gear and a shaft of the worm gear, and is separated in the X-axis direction and circumferentially. It is formed from a cylindrical coupling with a notched groove that includes a cylindrical body that has a plurality of notched grooves that are displaced in the direction and that can transmit rotational force and that can be expanded and contracted in the X-axis direction by the expansion and contraction force generated by the piezo actuator. Angle positioning device.

In this invention, when the piezo actuator is extended and contracted, the responsive displacement permitting means mounted between the worm gear shaft and the motor shaft responsively expands and contracts. Therefore,
The worm gear is slightly displaced by a distance corresponding to the amount of expansion and contraction of the piezo actuator in the X-axis direction with the motor as a fixed point. Therefore, the same operation and effect as those of the inventions of the second and third aspects can be obtained, and further, the structure can be further simplified, the size and weight can be further reduced, and the cost can be reduced.

Further, according to a fifth aspect of the present invention, the helical gear has a structure in which teeth are provided on an outer peripheral surface of a cylindrical body, and a rotary encoder connected to the rotary table is disposed in the cylindrical body. It is an angle positioning device.

In this invention, the rotary encoder detects the rotation angle position of the rotary table in the helical gear (cylindrical body). Therefore, the same effects as those of the inventions of claims 2 to 4 can be obtained. In addition, since the rotary encoder can be directly connected to the rotary table, the detection can be performed with higher precision and the planar size can be further reduced.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS.
As shown in FIG. 6, the helical gear 15 is attached to the rotary table 20 and the coarse angle adjusting means 30 including the worm gear 33 and the like engaged with the helical gear 15 and the backlash removing means 80 including the driven gear 82 and the urging means (84). And the piezo actuator 41 and the responsive displacement permitting means (35)
And the worm gear 33
Is rotated about the X-axis and about the Z-axis via the helical gear 15 to adjust the coarse angle of the rotary table 20, and utilizing the displacement of the piezo actuator 41 in the X-axis direction and using the worm gear 33 and By performing fine angle adjustment of the rotary table 20 via the helical gear 15, the rotary table 20 is formed so that the angle of the rotary table 20 can be accurately determined.

1 to 6, a cylindrical body 13 is fitted in a hollow portion 11 of the base 10 shown in FIG. 2, and a helical gear 15 is vertically mounted on the outer peripheral surface side of the cylindrical body 13 via a bearing 14. It is mounted so as to be rotatable about a Z-axis extending in the direction. A rotary table 20 is fixed to the helical gear 15 using a plurality of bolts 22 shown in FIG. That is, the helical gear 15 is mounted concentrically and synchronously rotatable on a rotary table 20 that can rotate about the Z axis.

The helical gear 15 is provided on the outer peripheral surface of the cylindrical body as shown in FIG.
3 is provided, and a rotary encoder 60 (detection shaft 61) connected to the rotary table 20 (fitting hole 21) is provided in the cylindrical body (specifically, the cylindrical body 13). It is fixedly provided by bolts 19.

The rotary encoder 60 includes a light emitting device, an optical slit disk, a light receiving device, and the like, and includes a detection circuit 65 including an amplifier, a division circuit, and the like shown in FIG.
9 is connected to the controller 70 shown in FIG. The detection accuracy (division ability) of the rotary encoder 60 itself is 0.1 degree, but in this embodiment, the secondary detection signal θi shown in FIG. Available for output.

The coarse angle adjusting means 30 is, as shown in FIG.
Worm gear 33 (shaft 33S) rotatable about the X-axis extending in the horizontal direction and meshable with helical gear 15
And a motor 31 connected via a coupling 35
(Motor shaft 31S, knob 36 for manual rotation).

This motor 31 is a stepping motor (SP · M), and has a connector 39 shown in FIG.
Are connected to the controller 70 via a cable 38C and a motor driver 38 shown in FIG.

Therefore, the worm gear 3 is
By rotating 3 (33G) about the X axis and rotating the helical gear 15 (15G) about the Z axis, the coarse angle of the turntable 20 can be adjusted.

As shown in FIGS. 1 and 3, the backlash removing means 80 is driven by the rotation of the helical gear 15 about a Z1 axis which is meshable with the helical gear 15 and extends in a vertical direction in parallel with the Z axis. A rotatable driven gear 82,
An urging means (spring 84) for urging the driven gear 82 in one direction of the Z1 axis (in the first embodiment, downward → upward shown in FIG. 3) is included, and the helical gear 15 (tooth 15G) The backlash between the helical gear 15 (15G) and the worm gear 33 (33G) can be removed by using the tooth inclination (surface) of the torsion angle θg shown in FIG.

In FIG. 3, the driven gear 82 (teeth 82G)
3 is rotatably mounted on the support shaft 81 via the bearing 83 and slidable in the vertical direction in FIG. 3, and the teeth 82G are brought into contact with the teeth 15G (tooth inclination) of the helical gear 15 by the urging force of the spring 84. I have. That is, the helical gear 15 can be rotated about the Z-axis in the direction indicated by the alternate long and short dash line in FIG. 6 (clockwise direction in FIG. 1). Due to the action of the horizontal rotation component component generated at the contact point between the two 82G and 15G based on the urging force of the spring 84.

Therefore, the teeth 15G meshing with the worm gear 33 of the helical gear 15 are the teeth 3G of the worm gear 33.
Since it is constantly pressed against the 3G from the right to the left in FIG. 1, backlash (play) between the two 33 (33G) and 15 (15G) can be reliably removed. This is the same even when the worm gear 33 is rotating in any direction (the same direction as the clockwise direction in FIGS. 2 and 6 or the opposite direction) about the X axis.

The fine angle adjusting means 40 is composed of a piezo actuator 41 shown in FIG. 1 and a responsive displacement permitting means (coupling 35). By displacing the piezo actuator 41 in the X-axis direction, the helical gear 15 is moved. The rotary table 20 is formed so that fine angle adjustment can be performed through the rotary table 20.

Motor 31 (shaft 31S) and worm gear 3
3 (axis 33S) and coupling 35
Is a cylindrical body (cylindrical body 35P) having a plurality of notched grooves 35S.
, And can transmit the rotational force from the motor 31 (31S) to the worm gear 33 (33S) side, and can expand and contract in the axis (X) direction by a forced external force in the X-axis direction.

The coupling 35 has a notched grooved cylindrical body having a plurality of notched grooves 35S spaced apart in the X-axis direction and circumferentially displaced as shown in FIG. 1 from a hollow cylindrical body 35P having a circular cross section. The rotation of the motor shaft 31S can be transmitted to the worm gear shaft 33S, and during rotation transmission, the dimension in the X axis direction is constant as long as no forced external force in the X axis direction is applied, but during rotation stop or during rotation transmission. Regardless of whether or not there is a certain external force applied X
The axial dimension can be changed by a very small amount.

That is, the drive shaft (31S) and the driven shaft (3
Focusing on the form and function of a general notched grooved coupling (35) that absorbs misalignment and runout with 3S), it is introduced as a response displacement permitting means. In the case of the first embodiment, the notched grooved cylindrical coupling 35 is
MISUMI's miniature coupling [set screw type (CPLS) ... made of stainless steel] with a diameter of 1
2mm, length 18.5mm, normal torque 0.3N
m, the maximum number of revolutions is 32000 rpm, the static torsional spring constant is 64 Nm / rad, and the allowable eccentricity is 0.10.

The number of the notched grooves 35S is four, each set being displaced in the circumferential direction, for a total of eight of the two sets. According to the measurement by the applicant, when a forced external force (corresponding to the extension force from the piezo actuator 41) is applied from both ends in the stationary state, the dimension (length) can be reduced by about 0.8 mm at the maximum and the forced external force can be removed. For example, it has been confirmed that the original size (18.5 mm) is restored by elastic return. Therefore, if the initial state is shortened by, for example, 10 μm, it is easy to expand and contract, for example, ± 8 μm in the axis (X) direction based on the state. In this embodiment, it is set to expand and contract by ± 5 μm in order to greatly improve the accuracy.

The responsive displacement permitting means may be formed by a coupling (35) with a torsion spring or bellows interposed in the middle. Further, the responsive displacement permitting means (35) may be mounted in the middle of the worm gear shaft 33S.

As shown in FIG. 1, the piezo actuator 41 has a base end 41B fixed to the base 10 via the position restricting member 18 so as not to be relatively displaceable in the X-axis direction.
Therefore, the distal end portion 41F can expand and contract in the X-axis direction.

The piezo actuator 41 according to the first embodiment is formed from a laminated piezoelectric actuator element (manufactured by NEC) and is displaced (0 to 150 V) by a voltage (0 to 150 V).
To 10 μm). Also, 75 V is constantly applied (biased) using the piezo driver 48 shown in FIG. 7, and the worm gear 33 is minutely moved by ± 5 μm in the X-axis direction around the coarse angle adjustment end position of the rotary table 20 (reference). It is formed to be displaceable. The piezo actuator cable 49 is, as shown in FIG.
It is pulled out from the base 10 side.

Further, a stepped shaft portion shown in FIG. 1 is fixed to the tip portion 41F of the piezo actuator 41, and this stepped shaft portion is connected via a miniature bearing 33B provided in a hollow portion 33H of the worm gear 33. Worm gear 33
Are mounted so as not to be displaceable in the X-axis direction and relatively rotatable about the X-axis.

The helical gear 15 has a module of 0.75, a pitch circle diameter of 54.1 mm, a number of teeth of 72, a twist angle (θg) of 3.6 degrees, and a tooth tip circle diameter of 5.
5.6 mm, the lead is 2701.777 mm, and the pitch (ts) is 2.356 mm. The twist angle θg
(3.6 degrees) is a right twist direction as shown in FIG. 6, but may be a left twist direction.

The worm gear 33 has a module of 0.75, a pitch circle diameter of 13.53 mm, a tooth tip circle diameter of 15.03 mm, a number of threads of 1 and a right-hand twisting direction (the left worm gear corresponds to the helical gear 15). The direction may be twisted.).

The driven gear 82 has a module of 0.75
The pitch circle diameter is 13.53 mm, the number of teeth is 18, the helix angle is 3.6 degrees, the tip circle diameter is 15.03 mm, and the lead is 6.
The helical gear structure has a pitch of 75.11 mm and a pitch (ts) of 2.356 mm.

That is, the driven gear 82 can generate a component force that comes into contact with the tooth inclination of the helical gear 15 (tooth 15G) and can rotate the helical gear 15 about the axis Z by the urging force of the spring 84. For example, a spur gear or the like may be used as long as it can mesh with the helical gear 15. In this embodiment, the meshing with the helical gear 15 can be made smoother and the urging force of the spring 84 can be strengthened while significantly reducing friction and noise. In this case, a helical gear structure having the same torsion angle θg as the helical gear 15 is used. However, the tooth width needs to be smaller (for example, 2 mm) than the tooth width (10.5 mm) of the helical gear 15. This is for generating a component in the rotation direction.

Thus, when the worm gear 33 makes one rotation about the X axis, the teeth (strips) 33G move in the X axis direction by the pitch of the helical gear 15 (ts = 2.356 mm), and the teeth 15G of the helical gear 15 Rotates about the Z axis by one tooth. Since the number of teeth of the helical gear 15 is 72, the helical gear 15, that is,
Rotate by degrees (= 360 degrees × 1/72). That is,
The coarse angle can be adjusted.

On the other hand, the worm gear 33 (teeth 33G)
Assuming that the tooth 15G of the helical gear 15 from which the backlash has been removed is 1 μm in the same direction when it is minutely displaced by, for example, 1 μm in the X-axis direction assuming that it is not rotating for the sake of convenience.
m. Since the displacement is small, the displacement (1 μm) is directly converted into a rotation angle about the Z axis, so that the helical gear 15 rotates by 0.002 degrees (= 5 degrees × 0.001 mm / 2.356 mm). I do. When the minute displacement of the worm gear 33 is set to 0.1 μm, the turntable 20 can be rotated by 0.0002 degrees about the Z axis. On the other hand, 5 μm (0.00
If it is displaced by 5 mm), it can be rotated by about 0.01 degrees.

In this embodiment, the piezo actuator 41 is set so as to be able to expand and contract by ± 5 μm in the X-axis direction, so that the maximum fine angle adjustment is within ± 0.01 degrees. Note that the minimum fine angle adjustment amount is ± 0.0003.
The following is also possible.

However, even if it is set to perform apparent angle positioning beyond fine angle adjustment that can be controlled by the motor 31, there is substantially no meaning as described above. Therefore, in this embodiment, a high accuracy (0.01) that can be controlled by the stepping motor (31) and is equal to or less than the detection accuracy (0.00025 degrees) of the rotary encoder 60 described above.
That is, the rotary table 20 is constructed so as to be able to position the angle in degrees. Of course, it is also possible to construct such that the angle can be positioned at, for example, 0.001 degrees.

In FIG. 7, the controller 70 has a CP
U71, ROM72, RAM73, operation panel (PN
L) 74, output port 75, interface (I /
F) includes a coarse angle adjustment amount corresponding signal θl to the motor driver 38 based on a program stored in the ROM 72.
Is output to perform the coarse angle adjustment, and the fine angle adjustment can be performed while outputting the fine angle adjustment amount equivalent signal θs to the piezo driver 48 using the second detection signal θi from the rotary encoder 60 as a feedback signal (θi). Is formed.

The operation panel 74 has a positioning setter 74 for setting an angle positioning set amount (θls = θl + θs).
P and coarse angle adjustment amount (θl) used only for coarse angle adjustment
, A fine angle adjustment setting device 74S that is used only for fine angle adjustment and sets the fine angle adjustment amount (θs), a direction setting device 74D that sets coarse / fine angle adjustment directions, and A speed setting device 74V for setting a moving speed at the time of coarse (fine) angle adjustment is provided.

Therefore, the angle positioning setting (.theta.ls) with respect to the reference position is set (FIG. 8).
(YES in ST10), coarse angle adjustment (ST1)
1 to ST14) and fine angle adjustment (ST15 to ST17) are continuously performed. In the case of coarse angle adjustment setting (S
In T18 (YES), coarse angle adjustment (ST19 to ST2)
When only 2) is possible and fine angle adjustment is set (ST23)
YES), only the fine angle adjustment (ST24 to ST27) is possible.

The controller 70 (71 to 73, 7)
5, 76) may be formed from, for example, hard logic, and the setting units 74P, 74L, 74S, 74D, 74V may be formed from, for example, digital switches. Further, signals corresponding to the respective setting signals to be set by using the setting devices 74P, 74L, 74S, 74D, and 74V are output from, for example, a personal computer 79 shown by a two-dot chain line in FIG. You may form so that input to the controller 70 is possible. In this case, the operation panel 74 may be excluded from the controller 70.

Next, the operation of the first embodiment will be described. First, the urging means (spring 84) forming the backlash removing means 80 urges the driven gear 82 meshed with the helical gear 15 upward in FIG. This driven gear 8
2 has a small tooth width (2 mm), so the tooth width (10.5 m
m) generates a rotational component in the direction indicated by the two-dot chain line in FIG. 6 on the teeth 15G of the helical gear 15 having a large value.

Therefore, the helical gear 15 is formed as shown in FIG.
Since the worm gear 33 is rotated in the clockwise direction about the axis, it is always in contact with the corresponding portion of the worm gear 33 (teeth 33G). That is, the backlash between both 15 (15G) and 33 (33G) can be removed. Of course, helical gear 1
With the rotation on the fifth side, the worm gear 33 is not rotated about the X axis.

Here, a bias signal (θs) is output to the piezo driver 48 from the output port 75 of the controller 70 shown in FIG.
Is applied. Then, since the base end portion 41B shown in FIG. 1 is fixed to the base 10 (position regulating member 18) so as not to be displaceable in the X-axis direction, the piezo actuator 4
1 extends rightward in FIG. 1 by 5 μm.

Therefore, the shaft 33S of the worm gear 33
Of the cylindrical coupling 35 with the notch groove provided between the motor shaft 31S and the motor shaft 31S that cannot be displaced in the X-axis direction (18.
5 mm) shrinks by 5 μm. Therefore, based on this state, if a forced external force is applied to the coupling 35 (reduced), the coupling 35 can be expanded and contracted by ± 5 μm in the X-axis direction.
Extremely easy.

Next, the motor shaft 31S and the worm gear 33 are manually rotated about the X-axis by using, for example, the knob 36, and the rotary table 2 is moved to the reference angular position (initial state).
0 is angularly positioned. In this state, a counter (not shown) forming a part of the rotary encoder 60 is cleared to zero.

Here, it is assumed that the rotary table 20 is positioned at an angle advanced by, for example, +10.00 degrees in the clockwise direction in FIG. 1 from the reference angular position. That is, FIG.
The angle positioning amount (+10.00 degrees = θls) is set using the angle positioning setting device 74P on the operation panel 74 shown in FIG. The moving speed is also set using the speed setting device 74V. Further, if necessary, the moving direction is set using the direction setting device 74D. However, when the angle positioning amount is set to ± 0.01 degrees, there is a case where the moving speed and the moving direction do not need to be set because the motor 31 does not need to be rotated.

When an angle positioning command is issued, the CPU 7
1 confirms that it is an angle positioning setting based on a program stored in the ROM 72 (YE in ST10 of FIG. 8).
S) Then, the angle positioning set amount θls (+10.00 degrees)
And outputs a corresponding signal θl (θls) [number of pulses] to the motor driver 38 shown in FIG. 7 (S
T12).

That is, since the drive power (current) is supplied via the cable 38C and the connector 39, the stepping motor (31) shown in FIG. 1 rotates in a predetermined direction (clockwise direction) (ST12). In this case, two rotations (720 degrees) are made. The coupling 35 transmits a rotational force to the worm gear 33 as a coupling function.

Accordingly, the worm gear 33 makes two rotations to move the streak (teeth 33G) to 4.7712 (= 2.356 × 2) m.
1 is moved to the left in FIG.
That is, the turntable 20 integrated therewith theoretically rotates clockwise about the Z-axis by 10.00 degrees.
That is, coarse angle adjustment is performed. At this time, since the rotation of the worm gear 33 is not transmitted to the piezo actuator 41 by the action of the miniature bearing 33B, there is no problem.

Then, from the rotary encoder 60 shown in FIGS. 1 and 7 connected to the rotary table 20, the detection signal of the momentarily changing rotation angle is divided into 400 second signals.
The detection signal θi is output. However, at this stage (coarse movement angle adjustment), it does not work as the feedback signal (θi). The CPU 71 sets the angle positioning set amount (θls = +
When the output of the signal θls (θ1) equal to 10.00 degrees) is completed, the switching point is determined (YES in ST14).
Then, the rotation of the motor 31 is stopped.

Here, the rotation angle amount (coarse angle adjustment amount θl) from the reference position (angle) of the rotary table 20 detected by the rotary encoder 60 is determined from the relationship with the minimum controllable step angle of the motor 31 and the like. For example +
Assume that it was 10.05 degrees. In other words, the coarse angle adjusting means 30 can perform angle positioning only with an accuracy of 0.05 (.about.0.03) degrees. In this case, +0.05
There is an error of degree (= 10.05-10.00).

Then, the CPU 71 determines that this error (+0.
05 degrees), the voltage (75 V) applied to the piezo actuator 41 is
In order to cancel the feedback signal (θi) from 0, for example, the voltage is boosted by 0.49 V (corresponding to 0.05 degrees) (75.4
9V = 75 + 0.49) (ST15, ST16).
Therefore, the piezo actuator 41 is
B is a fixed end, and its tip 41F is 0.
Extend by 0327 μm. At this time, the tip 41F of the piezo actuator 41 and the worm gear 33 cannot be displaced in the X-axis direction via the bearing 33B, that is, the relative position is constant.

Thus, the extension force of the piezo actuator 41 is applied via the worm gear 33 to the responsive displacement permitting means (the cylindrical coupling 35 with the notch groove) as a forced external force. Thus, the coupling 35 contracts (shortens) by 0.0327 μm in the X-axis direction with the stepping motor (31) side as a fixed end. That is, the entire worm gear 33 is moved (displaced) rightward in FIG. As a result, the worm gear 33 causes the helical gear 15 to slightly displace (0.0327 μm) in the X-axis direction. Therefore,
The turntable 20 is theoretically rotated by 0.05 degrees about the Z axis in a direction opposite to the clockwise direction in FIG.

Then, assuming that the second detection signal (θi) from the rotary encoder 60 is, for example, +9.999 degrees, the CPU 12 determines the error (−0.001 degrees).
To reduce the voltage to the piezo actuator 41 by 0.0975 V corresponding to 0.001 degrees [74.5
4V = 75.49-0.957].

This time, the tip 41F of the piezo actuator 41 contracts 0.0065 μm leftward in FIG. Accordingly, the reaction displacement permitting means (35) is capable of providing a small displacement (0.0065 μm) of the worm gear 33 in the X-axis direction.
m) is allowed. As a result, the turntable 20 theoretically rotates clockwise by 0.001 degrees. At this time, the second detection signal (θ
i) That is, the actual angle adjustment amount is (10.00 ± 0.00)
9) When the angle is less than or equal to the degree, the fine angle adjustment ends (Y in ST17).
ES). This actual detection angle (10.00 degrees) is displayed on a display (not shown). That is, high-precision angle positioning within ± 0.01 degrees or less with respect to the set angle position (10.00 degrees) can be performed. Therefore, the set angle (+
10.00) can be accurately positioned at the same angle.

Note that both the coarse angle adjustment shown in ST18 to ST22 and the fine angle adjustment shown in ST23 to ST27 in FIG. 8 can be executed independently.

According to the first embodiment,
The helical gear 15 is attached to the rotary table 20, and the coarse angle adjusting means 30 includes a worm gear 33 that meshes with the helical gear 15, the backlash removing means 80 including the driven gear 82 and the urging means (84), and the piezo actuator 41. And a fine angle adjusting means 40 including a reaction displacement permitting means 35. The worm gear 33 is rotated about the X axis, and the coarse angle of the rotary table 20 is adjusted about the Z axis via the helical gear 15, and the piezo is adjusted. Using the displacement of the X axis of the actuator 41 and the rotation table 2 via the worm gear 33 and the helical gear 15
Since it is formed so that the fine angle adjustment of 0 can be performed, the rotary table 20 can be angularly positioned with high accuracy (for example, ± 0.01 degrees) as the sum (difference) of the coarse angle adjustment amount and the fine angle adjustment amount. Since the driven gear 28 for removing backlash is driven by the rotation of the helical gear 15, the friction is low and the noise is low.

The helical gear 15 and the rotary table 20
Are integrally formed so as to be concentric and rotatable synchronously about the Z-axis, so that high-precision angle positioning can be performed and further downsizing can be achieved.

Further, the backlash removing means 80 attaches the driven gear 82 which can mesh with the helical gear 15 and can be driven to rotate about the Z1 axis by rotation of the helical gear 15 and the driven gear 82 in one direction of the Z1 axis. The helical gear 15 (15G) and the worm gear 33 are provided by using the tooth inclination (surface) of the helical gear 15 including a biasing means (spring 84) that can be urged.
(33G), so that the backlash is always generated regardless of the rotation direction and the rotation speed of the rotary table 20 and without generating frictional heat which may cause a problem. It can be removed, is simple in structure, has low noise, and can be realized at low cost.

Further, since the driven gear 82 has a helical gear structure having the same helix angle as that of the helical gear 15, meshing can be performed more reliably, and relative rotation can be more smoothly performed while ensuring removal of backlash. .

Since the worm gear 33 forming the coarse angle adjusting means 30 and the piezo actuator 41 forming the fine angle adjusting means 40 are relatively rotatable about the X axis, the coarse angle adjustment and the fine angle adjustment are performed. Can be performed simultaneously, so that the angle adjustment can be performed more quickly.

Further, since the Z-axis extends in the vertical direction, the X-axis extends in the horizontal direction, and the Z1-axis extends in the vertical direction in parallel with the Z-axis, it is particularly possible to reduce the height and size and reduce the weight. The structure is simple. Therefore, it becomes easy to stack the present apparatus in two stages on a linear motion table, for example.

Further, the responsively movable displacement allowing means is a worm gear 3.
3 has a plurality of cutout grooves 35S mounted between a shaft 31S of a motor 31 for applying a rotational force to the shaft 31S of the worm gear 33 and spaced apart in the X-axis direction and displaced in the circumferential direction. Since it is formed from a cylindrical coupling 35 with a notched groove that can transmit a rotational force and that can expand and contract in the X-axis direction by the expansion and contraction force generated by the piezo actuator 41, the structure is simpler. Further, the size and weight can be further reduced and the cost can be reduced. Further, it is only necessary to divert the conventional coupling (35) for absorbing misalignment and runout of the conventional example. Therefore, no burden is imposed on the layout and space.

Further, the helical gear 15 has a structure in which teeth 15G are provided on the outer peripheral surface of the cylindrical body, and the rotary encoder 60 connected to the rotary table 20 is disposed in the cylindrical body. Can be directly connected. Therefore, the detection can be performed with higher accuracy, and the planar size can be further reduced.

The piezo actuator 41 and the responsive displacement permitting means (the cylindrical coupling 35 with the notch groove) constituting the fine angle adjusting means 40 are the same as the worm gear 33 forming the coarse angle adjusting means 30 (X). Since they are arranged in series on the top, positioning accuracy can be greatly improved with high response.

(Second Embodiment) The second embodiment has a basic configuration (10, 20, 30, 40, 60, 7).
0, 80, etc.) are the same as in the first embodiment, except that the responsive displacement permitting means 50 has the structure shown in FIG.

In FIG. 9, the motor 31 has a motor shaft 3
1S is configured to be displaceable within a certain range in the X-axis direction. A bearing 53 fixed to a motor shaft 31S is provided in a bearing housing 51 of the stepping motor (31), and the motor shaft 31S is biased by a spring 54 in the direction of the piezo actuator 41 in the X-axis direction (FIG. 9). Stopper 5 urged to the left)
2 can be abutted. FIG. 9 is a graph showing the expansion force (forced external force Fp) from the piezo actuator 41 shown in FIG.
This shows a state where a bias is applied by ΔX (= 5 μm). The coupling 35 shown in FIG. 1 may be a general coupling having no notch groove 35S.

That is, the worm gear 33 and the motor shaft 3
1S means that relative displacement is impossible in the X-axis direction, that is, the relative position is constant. Therefore, the response displacement permitting means 50
In response to the expansion and contraction of the piezo actuator 41, the entire worm gear 33 integrated with the motor shaft 31S is allowed to move in the X-axis direction, that is, expand and contract.

Thus, according to the second embodiment,
In addition to achieving the same operation and effect as in the case of the first embodiment,
Furthermore, since the reaction displacement permitting means 50 can be formed integrally with the motor 31, further downsizing and cost reduction can be achieved.
Further, due to the structure of the stepping motor (31), the stepping motor 31 constructed in advance so that the motor shaft 31S can be displaced by a predetermined amount in the X-axis direction can be used as a response displacement permitting means, so that a greater cost reduction can be achieved.

(Third Embodiment) In this embodiment, the basic configuration is the same as that of the first embodiment (FIGS. 1 to 8). As shown, the driven gear 82 is moved in a direction orthogonal to the Z axis (X1).
To generate a component force capable of rotating the turntable 20 about the Z axis. FIG. 10 is a diagram corresponding to FIG.

That is, the urging means is formed by a notched grooved cylindrical coupling 85 similar to the notched grooved cylindrical coupling 35 forming the responsive displacement permitting means, and the Z1 axis is defined by X.
It is forcibly displaced in one direction and is fixed with a fixing screw 86. Therefore, assuming that the lower end of the notched grooved cylindrical coupling 85 is a fixed end, its upper end is X1 in FIG.
It is elastically displaced (deformed) in the opposite direction.

Thus, utilizing the restoring force due to the elastic displacement, the teeth 82G of the driven gear 82 can be pressed more strongly against the teeth 15G of the helical gear 15 than in the first embodiment. That is, backlash can be more reliably removed. In addition, since there is no spring 84 as compared with the first embodiment, there is no danger that the driven gear 82 jumps out of the support shaft 81 together with the bearing 83 during the operation, so that not only the assembly becomes simpler, but also the axial line The helical gear 15 of the driven gear 82 (82G) is caused by approaching and separating the Z1 with respect to the Z axis.
The strength of the pressing force (component force in the rotation direction) with respect to (15G) can be easily adjusted, and the applicability is wide.

(Fourth Embodiment) This embodiment is similar to FIG.
1, shown in FIG. That is, the basic configuration is the third
In this embodiment, the linear motion guide means 90 is further provided to achieve more complete backlash removal and higher accuracy of angle positioning.

The linear motion guide means 90 guides the piezo actuator 41 and the worm gear 33 (shaft 33S) linearly in the X-axis direction shown in FIG. 11 (corresponding to FIG. 1) and is not displaceable in the Y direction. And the structure as shown in FIG.

That is, two leaf springs 91 with holes 91H shown in FIG. 12C are combined at predetermined intervals in the X-axis direction using two retainers 93 and 94 shown in FIG. It constitutes a leaf spring structure. Worm gear 33
The shaft 33S is rotatably fitted via a bearing 92 shown in FIGS. 11 and 12A and 12B.
The lower ends of the two leaf springs 91, 91 are shown in FIG.
It is fixed to the base 10 with fixing screws 95 via retainers 96 and 97 shown in FIG.

Thus, the parallel leaf spring structure (91, 91)
Allows the axis 33S to respond to the displacement of the piezo actuator 41 in the X axis direction, but does not change its displacement in the Y direction shown in FIG. Therefore, the force (that is, the backlash removing force) of the backlash removing means 80 (coupling 85 with a notch groove) (the spring 84 in the first embodiment) pushing the worm gear 33 (33G) of the driven gear 82 is increased. be able to.

Thus, according to the fourth embodiment,
In addition to providing the same operation and effect as in the third (and first) embodiment, the backlash can be more reliably removed, so that more accurate angular positioning can be performed, and the structure of the piezo actuator 41 and the shaft 33S. Simplification and downsizing can be achieved.

Further, in the fourth embodiment, a stopper screw 98 shown in FIG. 11 is provided to provide a safety measure against a failure. That is, the stopper screw 98 is normally used.
Of the worm gear 33 (tooth 33G), for example, 0.1
mm, the displacement of the worm gear 33 (shaft 33S) in the Y direction when the backlash removing force becomes excessive during adjustment or the like is regulated to be small. Therefore, it is also useful for protecting the piezo actuator 41.

The motor (31) is not limited to the stepping motor disclosed in each of the above embodiments. For example, the present invention can be implemented by using an AC servomotor, a DC servomotor, or the like.

[0102]

According to the first aspect of the present invention, a helical gear is mounted concentrically and synchronously rotatable on a rotary table rotatable about the Z axis, and the helical gear is rotatable about the X axis. The worm gear meshes with a driven gear rotatable about the Z1 axis and driven by the rotation of the helical gear and urged in one direction of the Z1 axis or in a direction perpendicular to the Z axis, and rotates the worm gear to roughly rotate the rotary table. Since the angle can be adjusted and the worm gear is displaced minutely in the X-axis direction to form a fine angle of the rotary table, the angle of the rotary table can be adjusted by coarse angle adjustment and fine angle adjustment. It has the following excellent effects.

The angle positioning accuracy can be greatly improved (for example, 0.01 degrees or less) while miniaturization and weight reduction and long-term stable operation are guaranteed. Since backlash can be removed by using a driven gear that rotates following the rotation of the helical gear, the backlash can always be reduced irrespective of the rotation direction and the rotation speed of the rotary table, and the helical gear and the driven gear can be used. Since it is not necessary to finish the work with excessively high precision and uniformity, the cost can be reduced, and the frictional heat and noise can be significantly reduced. Since there is no wear of the helical gear due to friction, stable operation can be performed for a longer period, and also the power consumption of the motor can be reduced. With the backlash between the worm gear and the helical gear removed by using the tooth inclination of the helical gear, the angle of the rotary table can be positioned by a combination of coarse angle adjustment and fine angle adjustment. The speed of angle positioning can be increased while guaranteeing. Since the fine angle adjustment is performed by converting the linear displacement of the worm gear in the X-axis direction into the rotation angle of the helical gear, it is possible to achieve a high precision of, for example, 0.001 degrees or less. Because it is a combination of a helical gear and a worm gear,
In particular, the size and weight can be reduced by reducing the height. Therefore, for example, it is easy to stack and arrange two stages on a linear motion table. Since the coarse angle adjustment is performed by rotating the worm gear about the X-axis and the fine angle adjustment is performed by displacing the worm gear in the X-axis direction, the structure is simple and can be realized at low cost. In addition, since the worm gear can be formed so that rotation and displacement of the worm gear can be performed simultaneously, angular positioning can be performed at higher speed.

According to the second aspect of the present invention, a rotary table rotatable about the Z axis, a helical gear mounted concentrically and synchronously rotatable on the rotary table, and a rotary table about the X axis are provided. Coarse angle adjusting means for rotating the rotatable worm gear to adjust the coarse angle of the rotary table,
Backlash removing means including a driven gear meshing with the helical gear and being rotatable about the Z1 axis and a biasing means and capable of removing a backlash between the helical gear and the worm gear using the tooth inclination of the helical gear; A fine angle adjustment means for fine angle adjustment of the rotary table via a helical gear by displacing the worm gear in the X-axis direction using the displacement of the piezo actuator and a response displacement permitting means, The rotary table is formed so that angle positioning can be performed as the sum (or difference) of the coarse angle adjustment amount and the fine angle adjustment amount, so that the angle positioning accuracy can be greatly improved, and the size and weight can be reduced and stable operation can be performed for a long period of time. Can be achieved. In addition, since the piezo actuator and the worm gear are relatively rotatable about the X-axis, the coarse angle adjustment and the fine angle adjustment can be performed simultaneously, so that the angle adjustment can be performed more quickly.

According to the third aspect of the present invention, the Z-axis extends in the vertical direction, the X-axis extends in the horizontal direction, and the Z1-axis extends in the vertical direction in parallel with the Z-axis. In addition to achieving the same effects as the case of the invention of Item 2, it is possible to achieve a particularly compact and lightweight design with a short height and a simple structure.

Further, according to the fourth aspect of the present invention, the reaction displacement permitting means is mounted between the shaft of the motor for applying a rotational force to the worm gear and the shaft of the worm gear, and
A cylindrical body with a notched groove including a cylindrical body having a plurality of notched grooves separated in the axial direction and displaced in the circumferential direction, capable of transmitting rotational force, and capable of expanding and contracting in the X-axis direction by an expanding and contracting force generated by a piezo actuator. In addition to providing the same effects as those of the second and third aspects of the present invention, the structure is further simplified, the size and weight can be further reduced, and the cost can be reduced.

Further, according to the fifth aspect of the present invention, the helical gear has a structure in which teeth are provided on an outer peripheral surface of a cylindrical body, and a rotary encoder connected to a rotary table is disposed in the cylindrical body. In addition to the effects similar to those of the inventions according to the second to fourth aspects of the present invention, the present invention can be directly connected to the rotary table, so that the detection can be performed with higher accuracy and the planar size can be further reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a vertical side view based on an arrow of FIG. 1;

FIG. 3 is a cross-sectional view of a part of FIG.

FIG. 4 is a side view of the same as viewed from an arrow of FIG. 1;

FIG. 5 is a front view similarly seen from an arrow of FIG. 1;

FIG. 6 is a view for explaining a meshing state between a helical gear and a worm gear.

FIG. 7 is also a block diagram.

FIG. 8 is a flowchart for explaining the operation.

FIG. 9 is a side sectional view for explaining a second embodiment of the present invention.

FIG. 10 is a diagram for explaining a third embodiment of the present invention.

FIG. 11 is a partially sectional plan view showing a fourth embodiment of the present invention.

FIG. 12 is also a view for explaining a linear motion guide means.

FIG. 13 is a side view for explaining a conventional example (1) and its problems.

FIG. 14 is a partially sectional plan view for explaining a prototype and its problems.

[Explanation of symbols]

 Reference Signs List 10 base 11 hollow portion 13 cylindrical body 14 bearing 15 helical gear 15G tooth 20 rotary table 30 coarse angle adjusting means 31 motor 31S motor shaft 33 worm gear 33B bearing 33G tooth 33S shaft 35 Coupling with notched groove (responsive displacement permitting means) 35P cylinder Body (cylindrical body) 35S Notched groove 40 Fine angle adjusting means 41 Piezo actuator 41F Tip 41B Base end 50 Responsive displacement permitting means 52 Stopper 53 Bearing 54 Spring 60 Rotary encoder 65 Detection circuit 70 Controller 74 Operation panel 79 Personal computer 80 Backlash Removal means 81 Support shaft 82 Follower gear 82G Teeth 83 Bearing 84 Spring (biasing means) 85 Coupling with notch groove 86 Fixing screw 90 Linear movement guide means 91 Leaf spring 92 Bear Grayed

Claims (5)

[Claims] 1. A helical gear is attached to a rotary table rotatable about a Z-axis so as to be concentric and synchronously rotatable.
A worm gear rotatable about the X axis and a driven gear rotatable about the Z1 axis and driven by the rotation of the helical gear and urged in one direction of the Z1 axis or in a direction perpendicular to the Z axis are provided on the helical gear. The coarse angle of the rotary table can be adjusted by meshing and rotating the worm gear, and the fine angle of the rotary table can be adjusted by minutely displacing the worm gear in the X-axis direction. An angle positioning device formed so that angle positioning can be performed. 2. A rotary table rotatable about a Z-axis, a helical gear mounted concentrically and synchronously on the rotary table, and rotatable about an X-axis and meshable with the helical gear. Coarse angle adjusting means for rotating the worm gear to adjust the coarse angle of the rotary table, a driven gear meshable with the helical gear and driven to rotate around the Z1 axis, and the driven gear in one direction or the Z1 axis.
Backlash removing means including biasing means capable of biasing in a direction perpendicular to the axis and using a tooth inclination of the helical gear to remove a backlash between the helical gear and the worm gear; and A piezo actuator coupled to the worm gear so as to be displaceable and relatively rotatable about the X axis, and a reaction displacement permitting means for allowing displacement of the worm gear in the X axis direction in response to the displacement of the piezo actuator; A fine angle adjusting means for adjusting the fine angle of the rotary table via the helical gear by displacing the worm gear in the X-axis direction using the worm gear. 3. The apparatus according to claim 3, wherein said Z axis extends in a vertical direction and said X axis extends.
The axis extends in the horizontal direction and the Z1 axis is
3. The angle positioning device according to claim 1, wherein the angle positioning device extends in a vertical direction parallel to the axis. 4. A plurality of said reaction displacement permitting means are mounted between a shaft of a motor for applying a rotational force to the worm gear and a shaft of the worm gear, and are separated in the X-axis direction and displaced in the circumferential direction. 3. A cylindrical coupling having a notched groove, which includes a cylindrical body having a notched groove, is capable of transmitting rotational force, and is expandable and contractible in the X-axis direction by an expanding and contracting force generated by the piezo actuator. Item 3. The angle positioning device according to Item 3. 5. The helical gear has a structure in which teeth are provided on an outer peripheral surface of a cylindrical body, and a rotary encoder connected to the rotary table is provided in the cylindrical body. An angle positioning device described in any one of the above.