JPS598018A - Fine shifting device - Google Patents

Abstract

PURPOSE:To increse the rigidity in directions excepting the fine shifting direction with isotropy obtained in the vertical direction and at the same time to realize both miniaturization and general-purpose property for a fine shifting device using piezoelectric elements, by giving the piezoelectric driving force opposite to a traveling object with to piezoelectric elements. CONSTITUTION:Two parallel surfaces are formed to a traveling object 12 and in direction X and X' opposite to each other, and piezoelectric elements 13 and 14 having equal piezoelectric characteristics are made touch the two parallel surfaces. Then the voltage is applied to the elements 13 and 14 to extend these elements, and therefore these elements 13 and 14 produce voltage driving force in directions X and X'. Thus the rigidity is increased in direction excepting the fine shifting direction of the object 12, and at the same time the ridigity has no direction within the surface vertical to the fine shifting direction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fine movement device using a piezoelectric element.

This type of fine movement device is practically used in precision positioning devices and the like. Figure 1 shows the principle diagram.

1 is a base, and 2 is a moving body. The moving body 2 described above is bonded to the base 1 via the piezoelectric element 3. 4 is a thin layer of adhesive.

In this figure, the piezoelectric element 3 is illustrated as a nine-layer laminated piezoelectric element, but the piezoelectric element may be a single layer or a laminated layer. When a DC voltage V is applied to this piezoelectric element 3 from a power source 5, the piezoelectric element 3 expands in proportion to the DC voltage V, and moves the moving body 2 along the arrow
Make a slight movement in the x' direction.

In the conventional piezoelectric element fine movement device configured as described above, the base 1, piezoelectric element 3, and moving body 2 are glued together, so it is strong against compressive force in the x-x' direction, but The disadvantage is that the strength and rigidity in the direction perpendicular to ' are very low.

In order to compensate for the above drawbacks, a leaf spring 6 is interposed between the base 1 and the movable body 2 as shown in FIG.
Attempts have been made to increase the rigidity in the direction (vertical direction), but due to the installation of the leaf spring 6, the overall size of the fine movement device is 2.
It has the drawbacks of increased weight and directional stiffness in a plane perpendicular to the axis x-x'.

In addition, in the conventional fine movement device as described above, the base 1, the movable body 2, and the piezoelectric element 3 are glued together and integrated, so this fine movement device is specially designed for each purpose and condition of use. It had to be manufactured separately, and lacked versatility.

The present invention has been made in view of the above-mentioned circumstances, and has high rigidity in directions other than the fine movement direction of the moving body (the x-x' direction in the previous example), and has isotropic stiffness in a plane perpendicular to the fine movement direction.
Moreover, it is an object of the present invention to provide a fine movement device using a piezoelectric element that is compact in overall shape and has great versatility.

In order to achieve the above object, the present invention forms two parallel surfaces in opposite directions on a moving body, and brings piezoelectric elements 10 having equal piezoelectric properties '(il-) into contact with the two surfaces, respectively. The present invention is characterized in that the piezoelectric element is configured to apply a piezoelectric driving force in the opposite direction to the moving body.

Next, an embodiment of the present invention will be described with reference to FIGS. 3 to 6.

The movable body 12 is formed into a short cylindrical shape, and both end surfaces thereof are formed in parallel. A round bar 12 is placed perpendicularly to the center of both end faces above.
a, , 12b are integrally connected.

Two ring-shaped piezoelectric elements 13 with equal piezoelectric properties
, 14, whose outer diameter is made equal to the outer diameter of the movable body 12, and whose inner diameter is set so as to fit loosely into the round bars 12a, 12b.

A cylindrical frame 11 with a bottom that fits loosely on the outer diameter of the movable body 12 and an openable lid 15 are constructed, and a through hole 11a that loosely fits the round bar 12a is formed in the center of the bottom of the frame 11, and a through hole 11a that loosely fits the round bar 12a is formed in the center of the lid 15. A through hole 15a that loosely fits into the round bar 12b is provided in each of the holes 15a.

Ring-shaped piezoelectric elements 13 and 14 are fitted to round bars 12a and 12b connected to both end surfaces of the moving body 12, respectively, and brought into contact with both end surfaces of the moving body 12, and the round rod 12a is inserted into the through hole 11a. , ring-shaped piezoelectric elements 13 and 14 sandwich the movable body 12 in the frame 11. A round bar 12b is inserted into the through hole 15a, the opening of the frame 11 is covered with a lid 15, and the lid 15 can be fastened to the frame 11 with mounting bolts 16.

In this embodiment, as described above, the movable body 12 has two surfaces parallel to each other in opposite directions, the end surface facing the direction of the arrow X' and the end surface facing the direction of the arrow X. Ring-shaped piezoelectric elements 13 and 14 having characteristics are brought into contact with each other. Then, when a voltage is applied to the two piezoelectric elements 13 and 14 to cause them to expand, the two piezoelectric elements 13 and 1
4, piezoelectric driving forces are applied in opposite directions such as the arrow X direction and the arrow X' direction, respectively.

According to this embodiment, the moving body 12 has piezoelectric elements 13 on both sides.
. On top of that,
Since the moving body 12 and the piezoelectric elements 13 and 14 are not bonded together, they can be rearranged as desired. That is, it can be used in combination with a moving body (not shown) that differs only in the shape of the tip of the round bar 12a, and has a wide range of versatility. It's sweet.
Since there is no need to provide the leaf spring 6 as in the conventional device, the entire device can be made smaller and lighter.

Next, the detailed structure and method of use of the fine movement device of the above embodiment will be explained with reference to FIGS. 4 to 6.

FIG. 4 schematically depicts a vertical section of the fine movement device shown in FIG. 3. Power supplies 17 and 18 are connected to apply drive voltages to piezoelectric elements 13 and 14, respectively.

The voltage applied to the piezoelectric element 13 is assumed to be vl, and the voltage applied to the piezoelectric element 14 is assumed to be V2.

In a neutral state in which no driving voltage is applied to this fine movement device, both the voltage v1 applied to the piezoelectric element 13 by the source 17 and the voltage v2 applied to the piezoelectric element 14 by the power source 18 are set to voltage v
It should be configured so that it can be set to o. The above-mentioned voltage vo is set equal to a voltage that causes the piezoelectric elements 13 and 14 to elongate corresponding to 4 of the piezoelectric drive stroke.

With the piezoelectric elements 13 and 14 each extended by the O stroke as described above, the mounting bolt 16 of the lid 15 (
Figure 3). As a result, the moving body 12
The piezoelectric element 13 is supported without any play in the ' direction.

14 is in a state where a bias voltage of Vo is applied.

In order to move the movable body 12 in the direction of the arrow X', as shown in FIG. 14 mark 7Jn voltage is increased by V' above the bias voltage vo. This causes pressure
, the collector 13 contracts by a dimension δ' corresponding to the voltage V',
Pressure 1 at the same time! Since the purple child 14 extends by the same dimension δ' as above, the movable body 12 is moved by the dimension δ' in the direction of the arrow X'. As can be easily understood from this operation, the movable body 12 is held between the piezoelectric elements 13 and 14 in the same manner as before the movement even after the movement by the dimension δ', and no play occurs in the XX' direction.

Similarly to the above, in order to move the movable body 12 in the direction of the arrow
The voltage v2 applied to the piezoelectric element 14 by 8 is the bias voltage V
O and υ are also lowered by V'. As a result, the movable body 12 is moved in the direction of the arrow X by a dimension δ' corresponding to the voltage V'. When the two piezoelectric elements are extended, the two piezoelectric elements are applied with a pressure '*, and if a frame is provided to clamp the moving body by valving the elements, it is possible to prevent the moving body from shaking in the direction of slight movement with a simple operation as described above. It is also possible to move the above-mentioned moving body freely (for example, by fixing it to the round rods 12a and 12b).
If you fix both ends of the frame and perform the same operation, frame 11
can be moved arbitrarily in the x-x' direction, so
The practical application range of this fine movement device is expanded.

FIG. 7 is a perspective view of an embodiment different from the above, and FIG. 8 is a sectional view of the same.

The moving body 22 is formed into a cylindrical shape having a flange 22a and a bottom 22b, the piezoelectric element 24 is formed into a ring shape that fits loosely into the cylindrical part, and the piezoelectric element 23 is formed into a shape that can be housed in the cylindrical part. .

The frame 21 includes the above-mentioned flange 22a and the piezoelectric element 24.
A platform-shaped protrusion 21a that is configured to have a bottomed cylindrical shape and has an inner circumferential surface that fits loosely into the bottom surface, and a platform-shaped protrusion 21a that fits loosely on the inner circumference of the cylindrical portion of the moving body 22.
are installed in series. The lid 25 is formed into a ring shape that fits around the cylindrical portion of the movable body 22, and is fastened to the open end of the frame 21 with a mounting bolt 26.

The piezoelectric element 23 is interposed between the bottom 22b of the movable body 22 and the pedestal projection 21a of the frame 21, and is connected to a power source 27.

The piezoelectric element 24 is formed into a ring shape having the same area, the same thickness, and the same number of laminated layers so as to have the same piezoelectric characteristics as the piezoelectric element 23,
It is interposed between the flange 22a of the movable body 22 and the lid 24 and connected to the power source 28.

In this embodiment as well, the moving body 22 is given a piezoelectric driving force in the direction of the arrow X' by the expansion of the piezoelectric element 23 and in the direction of the arrow X by the expansion of the piezoelectric element 24, and operates in the same manner as in the previous embodiment. . According to this embodiment, both piezoelectric elements 23 and 24 can be installed on substantially the same plane (a plane perpendicular to x-x'), so
'It has a short directional dimension and a compact configuration.

As described above in detail, the present invention provides a fine movement device using a piezoelectric element, in which two parallel surfaces in opposite directions are formed on a moving body, and piezoelectric elements each having a characteristic of a pressure equal to 2UYi described above are used. By configuring the two piezoelectric elements to be in contact with each other and applying piezoelectric driving force in opposite directions to the movable body, the rigidity is large in directions other than the fine movement direction of the movable body, and the surface perpendicular to the fine movement direction. Excellent practical effects can be obtained in that the rigidity has no directionality within the structure, the overall shape and dimensions are compact, and the versatility is great.

[Brief explanation of drawings]

1 and 2 are side views of a conventional fine movement device using a piezoelectric element, FIG. 3 is a perspective view of an embodiment of the fine movement device of the present invention, and FIGS. 4 to 6 are views of the above embodiment. FIG. 7 is a perspective view of a different embodiment from the above, and FIG. 8 is a cross-sectional view of the same. 1... Base, 2... Moving body, 3... Piezoelectric element,
4... Thin layer of adhesive, 5... Power supply, 6... Leaf spring, 1
1... Frame, 12... Moving body, 12a, 12b
...Round bar, 13, 14...Ring-shaped piezoelectric element,
15...Lid, 16...Mounting bolt, 21...7V
-4, 22... Moving body, 22a... Flange, 22
b... Bottom, 23... Piezoelectric element, 24... Ring-shaped piezoelectric element, 25... Lid, 26... Mounting bolt, 2
7, 28...Power supply. Representative Patent Attorney Tadashi Akimoto Figure 3 Figure 2 Figure 4 Figure 5 Figure 6 C

Claims (1)

[Claims] 1. In a fine movement device using a piezoelectric element, two parallel surfaces in opposite directions are formed on the moving body, and each of the two surfaces is brought into contact with a piezoelectric element having the same piezoelectric characteristic t-i. Seshime,
A fine movement device characterized in that the two piezoelectric elements are configured to apply piezoelectric driving force in opposite directions to a moving body. 2. A means for applying a bias voltage to each of the two piezoelectric elements is provided, and the two piezoelectric elements are in an expanded state by the bias voltage, and the movable body is held between the two piezoelectric elements. 2. The fine movement device according to claim 1, further comprising a frame for controlling the movement of the fine movement device. 3. The movable body is formed into a bottomed cylindrical shape having seven flange, and is formed into a ring shape in which the two piezoelectric elements are externally fitted into the cylindrical part, and the other The fine movement device according to claim 1 or 2, characterized in that the piezoelectric element is shaped so as to be housed in the cylindrical portion.