JPS63140160A - Fine positioning device - Google Patents

Abstract

PURPOSE:To obtain high rigidity at the time of positioning by interposing piezoelectric elements between a pair of nuts screwed to a feed screw. CONSTITUTION:A nut supporting part 3, on both sides of which a pair of nuts 4, 5, are supported, is projected upward from the central portion of a moving body 1 freely movable on a base 2. Piezoelectric elements 6, 7 are interposed between the nut supporting part 3 and the nuts 4, 5, respectively. Meanwhile, a feed screw 9 having one end portion rotatably supported by a bracket 8 mounted on the base 2, is disposed with its axis in parallel to the moving direction of the moving body 1, and further has the pair of nuts 4, 5 screwed around the feed screw 9. The movement of the moving body 1 effects a coarse adjusting feed by the use of the feed screw 9 through the rotation of a motor 10. Therefore, a high voltage is applied to the piezoelectric elements 6, 7 so that gaps between the feed screw 9 and the nuts 4, 5 are eliminated, thereby the moving body 1 being fixed with high rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a micro-positioning device, and more particularly to a micro-positioning device that positions a movable body by moving it with a feed screw.

2. Description of the Related Art As a conventional micro-positioning device using a feed screw, one having a configuration as shown in FIG. 3 is known. In FIG. 3, reference numeral 21 denotes a movable body movable on the base 22, and a pair of support protrusions 23a-, 23b are protruded so as to face each other with an interval in the direction of movement. A piezoelectric cord 24 and an elastic body 25 are arranged between these support protrusions 23a and 23b, and these piezoelectric elements 24 and elastic body 2
A nut support member 26 is held between the nut support member 5 and the nut support member 26.

On the other hand, a feed screw 28 whose one end is rotatably supported by a bracket 27 installed on the base 2 is disposed with its axis along the moving direction of the movable body 21, and the bracket 27 It is configured to be rotatably driven by a drive motor 29 attached to. And this feed screw 2
A pair of nuts 30, 31 screwed together with the nuts 30 and 31 are attached to the nut support member 26 indicated by It has been intervened.

With this configuration, the biasing force of the compression spring 32 eliminates the gap between the pair of nuts 30, 31 and the feed screw 28,
In this state, the moving body 21 is coarsely fed by the feed screw 28, and the moving body 21 is moved by a minute amount by the piezoelectric element 24 to perform minute positioning.

Problems to be Solved by the Invention However, in such a configuration, the rigidity of the reference position when performing minute positioning of the moving body is determined by the rigidity of the contact part between the feed screw and the nut and the biasing force of the compression spring. There is a problem in that the positioning accuracy cannot be increased because of the storage, and if the biasing force of the compression spring is increased in order to increase the rigidity, the running performance during movement by the feed screw deteriorates.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problem α, an object of the present invention is to provide a micro-positioning device that can obtain high rigidity during positioning, has good torque, and has good runnability during movement by a feed screw.

Means for Solving the Problems In order to achieve the above object, the present invention makes a pair of nuts screwed onto a rotationally driveable feed screw non-rotatable and at least one nut movable in the axial direction. The present invention is characterized in that it is attached to the support part of the neck 1 of the moving body, and a piezoelectric element is interposed between the pair of nuts.

Function Since the present invention has the above-mentioned configuration, when a moving body is moved by a feed screw, the piezoelectric element can be shortened to increase the gap between the feed screw and the nut to improve running performance. During feeding and positioning, the piezoelectric element is expanded to eliminate the gap between the feed screw and the nut, and the contact area of the screw is strongly pressurized to achieve high rigidity.Also, since braking is applied to the feed screw, Even if the rotational drive of the feed screw is set to 79 -, the nut position does not change, and the positional viscosity does not decrease due to vibration of the drive motor.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG. Reference numeral 1 denotes a movable body that is movable on a base 2, and has a nut support portion 3 projecting upward from the center thereof, and a pair of nuts 4.5 supported on both sides of the nut support portion 3. The pair of nuts 4.5 are supported by the nut support portion 3 so as to be non-rotatable and movable in the axial direction. A piezoelectric element 6.7 is interposed between the nut support portion 3 and the nut 4.5, respectively. On the other hand, the feed screw 9, whose one end is rotatably supported by the bracket 8 installed on the base 2, moves its axis as described above. The pair of nuts 4.5 are screwed onto the feed screw 9, which is disposed along the moving direction of the h-body 1. Further, the feed screw 9 is configured to be rotationally driven by a drive motor 10 attached to the bracket 8.

Next, to explain the operation, when positioning the movable body 1 at a predetermined position, first the drive motor 10 is driven to rotationally drive the feed screw 9, and the movable body Coarse feed 1. At that time, the piezoelectric element 6.7
By applying a low voltage to the piezoelectric element 6.7, the gap between the feed screw 9 and the nut 4.5 is increased (to improve the running performance of the moving body 1 and move it smoothly). By applying a high voltage to stretch it, eliminating the gap between the feed screw 9 and the nut 4.5, and applying strong pressure,
To fix a moving body 1 in a position with high rigidity. Next, by changing the voltage applied to the piezoelectric element 6.7 in a contradictory manner at small intervals, the movable body 1 is sequentially moved at a minute pitch relative to the feed screw 9, and when a predetermined position is detected, it is positioned at that position. do. Therefore, the moving body 1 can be minutely positioned with high rigidity.

Next, a second embodiment will be described based on FIG.

In the first embodiment, the piezoelectric element 6.7 and the nut 4.5 are arranged on both sides of the nut support part 3, and the piezoelectric element 6.7 performs minute feeding. In the example, a pair of nuts 14 and 15 are made non-rotatable with respect to a nine-nut support portion 13 protruding from the movable body 11, one nut 14 is fixed, and the other nut 15 is moved in the axial direction. A piezoelectric element 16 is interposed between the nut support 13 and an axially movable nut 15, and a rotationally driveable feed screw 19 is screwed into the nut 14,15.

In this embodiment, by shortening the piezoelectric element 16, it is possible to improve the running performance when moving by the feed screw 19, and by expanding the piezoelectric element 16, it has high rigidity with respect to the feed screw 19. The movable body 11 can be positioned in this state. Incidentally, although within a very limited range, it is also possible to minutely feed the movable body 1 by expanding and contracting the piezoelectric element 16 and elastically deforming the contact portion between the feed screw 19 and the nut 1°4.15.

On the other hand, a minute feed mechanism can be provided separately, or conversely, it is not necessary to provide a minute feed mechanism.

Effects of the Invention According to the micro-positioning device of the present invention, as described above, by shortening the piezoelectric element and increasing the gap between the feed screw and the nut, the movable body can be moved with good running performance. High rigidity can be obtained during positioning by expanding the element to eliminate the gap between the feed screw and the nut and strongly pressurizing the contact portion of the screw. In addition, since braking is applied to the feed screw, the nut position does not change even if the feed screw is turned freely, and it is possible to eliminate the drop in position accuracy due to vibration of the drive motor. be effective.

[Brief explanation of the drawing]

tiS1 is a partially sectional front view of the first embodiment of the present invention, and FIG. 2 is a partially sectional front view of the main part of the second embodiment of the present invention.
FIG. 3 is a partially sectional front view of a conventional example. 1.11・・・・・・・・・・・・・・・・・・
Mobile object 2・・・・・・・・・・・・・・・・・・
・・・・・・・・・Base 3.13・・・・・・・・・
・・・・・・・・・Nut support part 4.5.14.
15...Natsuto 6.7.16...
・・・・・・Piezoelectric element 9.19・・・・・・・・・
・・・・・・・・・・・・Feed screw.

Claims (2)

[Claims] (1) A pair of nuts to be screwed onto a rotationally drivable feed screw are attached to a nut support portion of a movable body such that they are non-rotatable and at least one nut is movable in the axial direction, and between the pair of nuts, A micro-positioning device characterized by interposing a piezoelectric element. (2) The micro-positioning device according to claim 1, wherein a pair of nuts are arranged on both sides of a nut support part of the movable body, and a piezoelectric element is interposed between each nut and the nut support part. .