JPH0197538A - Positioning mechanism - Google Patents

Abstract

PURPOSE:To increase a positioning range and to improve precision and rigidity, by providing a frame, a stage, a piezoelectric element for securing the stage, a clamp base, a piezoelectric element for movement, and a piezoelectric element for securing the clamp base. CONSTITUTION:During securing of a stage 1, a piezoelectric element 2 for securing is expanded and by pressing upper and lower parallel surfaces, the stage is secured. During movement, a piezoelectric element 3 for securing a clam base is first expanded to secure a clamp base 7, and secondly the piezoelectric element 2 is contracted to bring the clamp base into a moving state. By means of a piezoelectric element 4 for movement, the clamp base 7 is moved by a necessary positioning amount in an X-axis direction, an Y-axis direction, and a theta-axis direction. After movement, through expansion of the piezoelectric element 2, the stage 1 is secured and the piezoelectric element 3 is contracted. During movement by a slight distance within the motion range of the piezoelectric element 4, displacement of the piezoelectric element 4 is controlled, and during movement by a large distance, movement to the vicinity of a target distance is effected through a measuring wormlike motion, and thereafter, displacement of the piezoelectric element 4 is controlled for positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning mechanism used in precision instruments.

[Conventional technology]

Conventionally, positioning mechanisms using piezoelectric elements include a mechanism in which the movable part is directly driven by the piezoelectric element, and a displacement magnification mechanism in which a lever is combined to magnify the minute displacement of the piezoelectric element as shown in Figure 3. A mechanism for this is known. This conventional example includes a piezoelectric element 11, a frame 12, hinges 13, 14, 15, 16, 17, arms 18, 19, .
20. Also, as shown in Fig. 4, it has a pair of clamp parts and an extendable part for moving the clamp parts,
A mechanism is also known in which the positioning is performed on the negative axis by an inchworm-like method in which clamping is performed alternately and the clamping parts are moved by a telescoping part. This conventional example includes a frame 21,
It includes a moving piezoelectric element 22 and a fixed piezoelectric element 23. As a θ-axis positioning mechanism using a piezoelectric element, there is a mechanism in which a movable part is supported by a leaf spring and the θ-axis is moved by the piezoelectric element. Furthermore, a mechanism is also known that uses an inchworm-like method for rotation to perform rotation about the θ axis.

[Problem that the invention seeks to solve]

In the method of directly driving the movable part with a piezoelectric element, the movement range is limited by the stroke of the piezoelectric element, so even if a laminated piezoelectric element, which has a large displacement among piezoelectric elements, is used,
The limit of movement range was about several tens of micrometers. In addition, in the method using a displacement amplification mechanism, compared to the case of direct drive,
Although a maximum magnification of several tens of times can be obtained, there is a problem in that the rigidity decreases. In addition, in a structure that uses leaf springs for support, in the case of an inchworm-like mechanism where the travel distance and rotation angle are limited, the -axis movement is normal, and when three or more axes are combined, the structure becomes complicated. , and the rigidity decreases significantly.

[Means for solving problems]

The positioning mechanism of the present invention includes a frame having parallel surfaces facing each other, a stage, one end fixed to the periphery of the stage, extended substantially perpendicular to the parallel surfaces, and fixed the stage between the parallel surfaces, and compressed. a stage fixing piezoelectric element that allows the stage to move relative to the parallel plane; a clamp base; and one end fixed to a side surface of the stage;
a pair of moving piezoelectric elements whose other ends are fixed to the clamp base and expand and contract to move the clamp base substantially parallel to the parallel plane; The present invention is characterized by comprising a clamp base fixing piezoelectric element that is extended to fix the clamp base between the parallel surfaces and contracted to make the clamp base movable with respect to the parallel surfaces.

[Effect]

In the present invention, the stage and the clamp base can be positioned arbitrarily in both the X-axis direction and the Y-axis direction within the movement range of the piezoelectric element, so the stage can be moved in the X-axis, Y-axis, and θ-axis simultaneously in three axes You can do it freely. Furthermore, even when the movement distance exceeds the movement range of the piezoelectric element, the
Since the clamp base, which moves in all three axes, Y-axis and θ-axis, moves on the − plane by inchworm movement, it is possible to obtain the necessary positioning range.

In addition, the structure is simple, and the stage can be
It has high rigidity because it is directly fixed to the parallel plane of the main body from both sides by the fixed piezoelectric element.

〔Example〕

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

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and this diagram is a view taken from the upper side of two opposing parallel surfaces of the flail 5. Figure 2 shows A-A in Figure 1.
FIG. Stage 1 has stage fixing piezoelectric elements 2 fixed at a total of eight locations, four on the front and four on the back. A total of four runer bases 7 are fixed to the side surfaces of the stage 1, supported by two piezoelectric elements 4 for movement in the X-axis direction and the Y-axis direction, respectively, and clamp bases fixed to the upper and lower surfaces of the clamp bases 7 are fixed to the sides of the stage 1. The piezoelectric element 2 for use is fixed. Note that a metal or ceramic contact member 8 is attached to the parallel plate side of the fixing piezoelectric elements 2 and 3 to prevent wear. In addition, the stage 1, which is provided with a hinge 6 to prevent bending moment from acting on the moving piezoelectric element, presses the upper and lower parallel surfaces when the fixed piezoelectric element 2 is stretched when it is fixed. Fixed.

During movement, the fixing piezoelectric element 3 of the clamp base 7 is first extended to fix the clamp base 7, and then the fixing piezoelectric element 2 of the stage 1 is contracted to become movable. Then, the clamp base 7 is moved by the moving piezoelectric element 4.
Move by the required positioning amount in the X-axis direction, Y-axis direction, and θ-axis. After moving, the stage 1 is fixed to the fixing piezoelectric element 2.
The fixing piezoelectric element 2 of the clamp base 7 is contracted. Note that the movement order may be such that the clamp base 7 is moved first, then fixed, and then the stage 1 is moved.By 0 or more movements, the movement piezoelectric element 4 can be moved slightly within the movement range. When it comes to distance,
By controlling the displacement of the moving piezoelectric element 4 and directly driving the stage 1, it is possible to accurately move the X-axis direction, Y-axis direction, and θ.
Axis positioning can be done. When moving a large distance, repeat the above-mentioned inchworm-like motion with a fixed amount of movement to move close to the target distance, and then control the displacement of the moving piezoelectric element 4 to perform precise movement. By performing accurate positioning, highly accurate positioning can be performed. In this figure, the stage 1 is fixed at four locations and there are four clamp bases, but the number of these may be arbitrary.

In this way, it becomes possible to position with high accuracy any distance and angle in the X-axis direction, Y-axis direction, and θ-axis.

〔Effect of the invention〕

According to the present invention, an X-axis, Y-axis, and θ-axis positioning mechanism with a large positioning range, high precision, and high rigidity can be realized with a simple configuration.

[Brief explanation of the drawing]

Figure 1 is a top view of an embodiment of the present invention, and Figure 2 is A of Figure 1.
-A cross-sectional view, FIGS. 3 and 4 are configuration diagrams of a conventional example. 1... Stage, 2... Piezoelectric element for fixing the stage,
3... Piezoelectric element for fixing the clamp base, 4... Piezoelectric element for movement, 5... Frame, 6... Hinge, 7...
...Clamp base, 8...Contact member.

Claims (1)

[Claims] a frame having parallel surfaces facing each other; a stage; one end fixed to the periphery of the stage, extended substantially perpendicular to the parallel surfaces, and the stage fixed between the parallel surfaces;
a piezoelectric element for fixing a stage that can be contracted to move the stage relative to the parallel plane; a clamp base; one end fixed to a side surface of the stage; the other end fixed to the clamp base as a pair; a moving piezoelectric element for moving the clamp base substantially parallel to the parallel plane; one end fixed to the clamp base, extended substantially perpendicular to the parallel plane, fixing the clamp base between the parallel planes, and contracting the clamp base; A positioning mechanism characterized by comprising a clamp base fixing piezoelectric element that allows the clamp base to move between the parallel surfaces.