JPH01220716A - Minute rotary device - Google Patents

Abstract

PURPOSE:To enable operation for a long term without use of lubricant by radiately providing a plurality of thin plates like elastic members, between a rotational center and a fixed portion located on the circumference thereof, one end of which is fixed to the fixed portion and the other end is fixed to a rotary portion. CONSTITUTION:An elastic member 6 is stretched between a rotary portion 4 located on a rotational center and a fixed portion 5 located on the circumference thereof and the rotary portion 4 is concentrally fixed to the output shaft 2 of an electric motor 1. The elastic member 6 is made of a plurality of thin plates like steel plate etc., and one end is fixed to a rotary portion 4 and the other end is fixed to a fixed portion 5. In this construction, if an output shaft 2 is minutely rotated in an arrow C direction, only rotary torque is transmitted to the concentric rotary portion 4 so that the rotational center does not shift eccentrically in a radial direction and minute rotation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a micro-rotating device suitable for use in semiconductor manufacturing processes that require alignment accuracy and in vacuum environments such as outer space.

[Prior Art and Problems to be Solved by the Invention] In general, rotating equipment uses bearings such as rolling bearings and skid bearings to support its rotating shaft. However, when high-speed swinging operation is performed at a minute rotation angle of less than one revolution, it becomes difficult for sufficient lubricant to spread to the contact surface between the rotating shaft and the bearing, resulting in wear and seizure due to poor lubrication. Furthermore, when used under high vacuum, lubricants commonly used for bearings release internal substances as gas, which is undesirable since it contaminates the environment.

Therefore, it is necessary to use lubricants with low gas release, such as special grease for high vacuum or solid lubricants, but these are expensive, and bearing wear occurs during use, resulting in poor performance such as rotation accuracy. deterioration is inevitable.

The present invention solves these conventional problems, and it is possible to repeat rocking rotation at a minute angle for a long period of time without the need for lubricant, and it is possible to perform minute rotation without causing deviation in the center of rotation. The purpose is to provide equipment.

[Means to solve the problem]

The present invention, which achieves the above object, is capable of minute rotation at the rotation center by an elastic member stretched between the rotation center and a fixed part located at a circumferential position of the rotation center so as to be deflectable only in the rotation direction. It includes a supported rotating part and a rotational drive means connected to the rotating part so as to transmit only rotational torque.

It is effective to construct the elastic member by radially arranging a plurality of thin plates, one end of which is fixed to the fixed part, and the other end of which is fixed to the rotating part.

It is preferable that tension is applied to the thin plate by a tension applying means.

Further, the output shaft of the rotational drive means and the rotating section may be connected to each other so as to transmit only the rotational torque via a speed reduction mechanism having an arcuate surface centered on the rotation center.

[Effect]

The micro-rotating device configured as above includes rolling bearings,
Since no bearings such as sliding bearings are used, there is no need for lubricants such as grease, and no environmental pollution occurs even in high vacuum. When the driving means is rotationally driven, only rotational torque is transmitted to the rotating part, and the rotating part rotates by a small angle until the rotational torque is balanced with the elastic force in the rotational direction of the elastic member.

In that case, the thinner the elastic member is, the more accurately the position of the rotation IE center can be maintained. If it is thick, variations in thickness and misalignment of the mounting will increase, resulting in poor positioning accuracy.

Further, by applying tension to the elastic member, large rigidity can be obtained despite the thin thickness, so the position of the center of rotation can be further stabilized.

Even when a speed reduction mechanism is incorporated, the weight of the speed reduction mechanism is supported so as not to be applied to the rotating member, thereby preventing deviation of the center of rotation and achieving precise rotation.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention, in which a minute rotation mechanism 3 is directly connected to an output shaft 2 of an electric motor 1, which is a rotational drive means.

This minute rotation mechanism 3 is formed by extending an elastic member 6 between a rotating part 4 located at a rotation center 0 and a fixed part 5 located at a circumferential position thereof. is concentric with the output shaft 2 of the electric motor, and both are fixed. Therefore, only the rotational torque of the electric motor 1 is applied to the rotating portion 4.

The elastic member 6 in this case is composed of, for example, four thin steel plates. Each thin steel plate is measured in the length direction (direction of arrow a)
The width direction is aligned with the direction of the rotation axis so that the spring constant is strong against the acting force in the width direction (direction indicated by the arrow mark), but weakest in the direction of rotation (direction indicated by the arrow mark C and d), and one end is is fixed to the rotating part 4, and the other end is fixed to the fixed part 5.

In order to improve the rotation accuracy of the micro-rotating device, it is desirable that the elastic member 6 made of a steel plate has a thinner plate thickness.

On the other hand, if it is thin, its rigidity is low, so it is easily deformed even when a weak force is applied, and the supporting force for the rotating part 4 becomes unstable. To cope with this, in this embodiment, tension is applied to the elastic member 6 by a tension applying means to increase the rigidity.

As the tension applying means, for example, heating means, mechanical tensioning means, etc. can be used. In the former case, the elastic member 6
is heated and becomes fixed in an expanded state at a temperature higher than the upper limit of the operating temperature. Then, when the temperature for use is reached, high tension is applied by contraction.

In the latter case, although not shown, for example, the fixing part 5 is attached to the frame via a screw, and is formed so as to be able to adjust its position to some extent in the diametrical direction with respect to the center of rotation O. Then, after adjusting the distance between the rotating part 4 and the fixed part 5 to the minimum and fixing the ends of the elastic member 6 to both parts 4.5,
If the fixing part 5 is moved outward using the screw, a high tension is applied to each elastic member 6.

Next, I will explain the effect.

Start the electric motor 1 and move its output shaft 2 to the arrow mark C in FIG.
When a small rotation is made in the direction, only rotational torque is transmitted to the concentric rotating portion 4. Therefore, the center of rotation O does not shift in a radial direction, and extremely precise rotation can be achieved. Further, even if a lateral force acts on the output shaft 2, the rotating portion 4 is preloaded by the elastic member 6 toward the rotation center 0, and the position of the rotation center 0 hardly changes in the radial direction.

Furthermore, since each elastic member 6 made of a thin steel plate has a strong resistance force in the width direction, the rotating part 4 supported by the elastic member 6 does not move at all in the axial direction of rotation.

On the other hand, in the rotation direction of the electric motor 1 with a weak spring constant,
Since the elastic member 6 is easily bent as shown in FIG. 2, the rotating portion 4 of the minute rotation mechanism 3 rotates minutely together with the output shaft 2 of the electric motor 1.

In this way, a precise rotational output is obtained at the tip of the output shaft 2 without axial movement or deviation of the rotation center 0.

Moreover, since the rotating part 4 of the micro-rotation mechanism is supported in a structure with no friction surfaces, there is no wear, no lubricant is required, and high-speed rocking operation at small angles in the directions of arrows c and d is possible. There is no problem in long-term operation under high vacuum conditions.

FIGS. 3 and 4 show a second embodiment.

This has an integrated micro-rotation mechanism 3 built into the bearing position within the case IOA of the electric motor 10.

That is, this minute rotation mechanism 3 is integrally formed with a central rotating part 14, a ring-shaped fixed part 15 fitted into the inner surface of the motor case IOA, and a thin plate-shaped elastic part 16. Usually, a bearing (a bearing using a lubricant, such as a rolling bearing) of the output shaft 2 of the electric motor 10 is arranged and fixed at a location where it is to be installed.

In the figure, 11 is a stator, and 12 is a rotor. Now, when the rotor 12 receives a rotational force e due to the excitation force of the stator 11, the rotating part 14 of the micro-rotation mechanism 3 fitted to the output shaft 2 causes the rotational force The elastic portion 16 undergoes a slight rotation in response to the force, and the elastic portion 16 curves and deforms as in the case of FIG. 2, thereby achieving the same function as that of the first embodiment.

FIGS. 5 and 6 show a third embodiment.

This device is equipped with a set of micro-rotation mechanisms 3.3, which are substantially similar to the one shown in FIG.
4 integrally connected by a rotary plate 20 is attached to a frame 21 together with the electric motor 1, and the output shaft 2 of the electric motor 1 and the rotary plate 20 are connected via a speed reduction mechanism 22.

The speed reduction mechanism 22 described above includes an arcuate plate 24 having an arcuate surface 23 centered on the rotation center 0, and steel belts 25 and 26 that connect the arcuate plate 24 and the output shaft 2 of the electric motor.

The arcuate plate 24 is integrally fixed to the upper surface of the rotary plate 20 and at the center of both support parts, and is rotatable together with the rotary plate 20 about the rotation center O by an amount f1 and g+ force direction. One end of the steel belt 25 is fixed to the upper end side of the arcuate surface 23 of the arcuate plate 24 with a screw 27, and the other end is fixed to the output shaft 2 with a screw 28 after being wrapped around the output shaft 2 of the motor for about half a turn.
is fixed. Further, one end of the other steel belt 26 is fixed to the lower end side of the arc surface 23 of the arc plate 24 with a screw 29. The other end is fixed to the output shaft 2 with a screw 30 after being wound around the output shaft 2 of the electric motor for about half a turn in the opposite direction to the steel belt 25 .

With this configuration, the weight of the rotating plate 20 is
It is supported by the output shaft 2 of the electric motor via steel belts 25 and 26, and the unbalanced load on the rotating part 4 due to the arc plate 24 is removed. Therefore, only the rotational torque by the electric motor 1 is applied to the rotating part 4, and there is no rotational moment due to an unbalanced load, and no deviation of the rotation center O occurs.

Now, when the electric motor 1 is started and its output shaft 2 is slightly rotated in the direction of the arrow mark f in FIG. As a result, the arcuate plate 24 receives a moving force along the arcuate surface 23 in the direction indicated by the arrow symbol f, and together with the rotating part 49 and the rotating plate 20, rotates slightly around the rotation center 0.Output shaft 2
When rotated in the opposite direction in the g direction, the steel belt 25 wraps around the output shaft 2, while the steel belt 26 wraps around the output shaft 2.
move away from As a result, the arcuate plate 24 receives a moving force along the arcuate surface 23 in the direction of arrow sign g+, and the rotating part 41 rotating plate 2
0 as well as a slight rotation in the opposite direction to the above about the rotation center 0.

Therefore, when the radius of the arcuate plate 240 is R1 and the radius of the output shaft 2 is r, the rotation of the output shaft 2 is reduced to the reduction ratio r/R, and the rotary plate 20 and thus the rotary unit 4 can be rotated.

Note that the elastic member 6 in this embodiment is also stretched with a predetermined tension applied thereto in the same manner as described above.

Further, in each of the above embodiments, the rotating part 4 is formed by four elastic members 6.
Although the case where the support is supported is described above, it is not limited to this, and it is sufficient if there are two or more sheets.

〔Effect of the invention〕

As explained above, according to the present invention, the following various effects can be obtained because of the above configuration.

The rotating part is supported by an elastic member that is flexible only in the direction of rotation, and only the rotational torque of the driving means is transmitted to this rotating part, so no lubricant is required and there is no wear even during high-speed rocking motion. It is possible to operate for a long period of time.

In addition, even under high vacuum, the problem of poor lubrication does not occur, and the lubricant does not contaminate the environment.

Further, by applying tension to the elastic member that supports the rotating part, the rigidity can be increased and the thickness can be reduced, and the positional accuracy of the center of rotation can be made extremely precise.

In addition, the weight of the speed reduction mechanism is supported by the output shaft of the drive means, so there is no weight imbalance in the rotating parts, and deviation of the center of rotation can be prevented, preventing deterioration of rotation accuracy even during long-term operation. do not have.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of the first embodiment of the present invention, Fig. 2 is a front view thereof for explaining the operation, Fig. 3 is a vertical sectional view of the second embodiment, and Fig. 4 is A sectional view taken along the line IV-IV in Fig. 3,
Figure 5 is a front view of the third embodiment, and Figure 6 is the Vl of Figure 5.
-Vl line sectional view. 1 is an electric motor (rotation drive means), 2 is an output shaft, 3 is a minute rotation mechanism, 4 is a rotating part, 5 is a fixed part, 6 is an elastic member, 22
23 is a deceleration mechanism, and 23 is an arcuate surface. Figure 1 Figure 3 Figure 2 Figure 4

Claims (4)

[Claims] (1) Between the center of rotation and the fixed part located at its circumferential position,
a rotating part that is slightly rotatably supported at the center of rotation by an elastic member stretched so as to be deflectable only in the rotational direction; and a rotational drive means that is connected to the rotating part so as to transmit only rotational torque. A micro-rotating device equipped with (2) The micro-rotating device according to claim 1, wherein the elastic member comprises a plurality of thin plates having one end fixed to the fixed part and the other end fixed to the rotating part. (3) The micro-rotation device according to claim 2, wherein tension is applied to the thin plate by tension applying means. (4) The micro rotation device according to claim 1, 2 or 3, wherein the output shaft of the rotational drive means and the rotating section are connected via a speed reduction mechanism having an arcuate surface centered on the rotation center.