JPH0690037A - Piezoelectric displacement device - Google Patents

Abstract

PURPOSE:To provide a title device which can obtain a suitable generation force and a large displacement by high-speed drive with regard to this device utilizing displacement and force generated by deforming a piezoelectric body. CONSTITUTION:A bimorph displacement piece 1, 1 is formed by laminating a metal base 5 with a piezoelectric body 4 having polarization regions 2a, 2b, 2c... or electrodes 3a, 3b, 3c... divided into a plurality in a longitudinal direction. After many displacement pieces 1, 1 are so piled up that apexes of deflection generated when these displacement pieces 1,1 deflect may overlap, they are depressed in the pileup direction by means of a restoration force such as of a belville spring 13 or lining of a synthetic resin to constitute an integral displacement device. This constitution causes bimorph displacement pieces 1, 1 to be displaced by an amount of a multiplied number of pileups. Further, apexes of deflection with many curvatures are made to serve as points of output support, so that a large generation force can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric displacement element that utilizes displacement and force generated by deforming a piezoelectric body.

[0002]

2. Description of the Related Art Recently, micron unit alignment has become necessary for IC manufacturing equipment and precision processing machines, and actuators used therefor have been demanded. And in order to respond to this, it is called a laminated piezoelectric actuator element,
A large number of thin plate-shaped piezoelectric bodies having a thickness of several hundreds of μm are stacked and deformed in thickness to obtain a large amount of displacement and generated force with a low driving voltage.

Further, conventionally, called a bimorph type element, two piezoelectric bodies are laminated with their polarization directions reversed, or a metal plate and a piezoelectric body are laminated (radius).
No, there was something that got a large amount of displacement.

[0004]

However, in the laminated piezoelectric actuator element, since a large number of piezoelectric bodies are connected in parallel, the electrostatic capacity becomes large and the capacitor load of the driving circuit increases, which is not suitable for high speed driving. It was. Also,
There is a limit to the amount of displacement, and the application range has been limited to a small size unless a displacement magnifying mechanism is provided separately. Further, although a large generating force of several kilometers per square centimeter can be obtained, the applications requiring such a large force have been limited.

On the other hand, the bimorph type element can obtain a large displacement amount by itself, but the generated force is small, and it is used only when a force such as driving a relay or a sensor is not so required.

Therefore, the present invention focuses on solving such a problem, and an object thereof is to provide a piezoelectric displacement element capable of obtaining an appropriate generated force and a large displacement amount.

[0007]

In order to solve such a problem, the present invention has the following technical means.

That is, two piezoelectric bodies polarized in the thickness direction are bonded to each other in opposite polarization directions, or one piezoelectric body and a metal plate are bonded to each other with an adhesive to form a bimorph displacement piece. After that, the bimorph-shaped displacement pieces are alternately stacked back to back so that the vertices of the flexure when the flexures are bent overlap with each other, and are housed to form an integral displacement element. Then, a plate of a rigid material serving as an output end is placed on both sides of this laminated bimorph displacement piece, and the laminated bimorph displacement piece is pressed by a spring in the stacking direction.

Plates made of a rigid material are placed on both end faces of the laminated bimorph type displacement piece in the laminating direction, and the entire periphery is molded with synthetic resin to form an integral displacement element. The synthetic resin surface covering the plate of the rigid material is used as an output end to the outside, and the laminated bimorph displacement piece is pressed in the stacking direction by the plate of the rigid material covered by the elasticity of the rigid resin.

Plates made of a rigid material are placed on both end faces in the stacking direction of the above-mentioned laminated bimorph type displacement piece and housed in a soft case such as aluminum to form an integral displacement element. Alternatively, both ends of the case are thickened to replace the rigid plate. Then, the end face of the case is used as an output end to the outside, and the elasticity of the side wall presses the laminated bimorph displacement piece in the laminating direction through the plate of the rigid material.

Further, the piezoelectric body is divided into a plurality of areas in the plane direction, polarized in opposite positive and negative directions in adjacent divided areas, and a voltage is applied to both surfaces of the piezoelectric body.

Further, electrodes are formed by dividing the piezoelectric body into several parts in the plane direction, and voltages are alternately applied in the positive and negative opposite directions in the adjacent divided regions.

[0013]

First, when a voltage is applied to the laminated bimorph type displacement piece, the bimorph type displacement piece bends with a curvature perpendicular to the surface. At this time, since the vertices of the arc-shaped deflection overlap with the vertices, the displacement amount obtained by multiplying the displacement of one bimorph displacement piece by the number of laminations is output to the output ends at both ends of the laminated bimorph displacement piece. After that, when the voltage application is stopped, the output ends at both ends of the laminated bimorph type displacement piece pressed by the force of the spring are restored.

When a voltage is applied to the laminated bimorph type displacement piece integrally molded with the synthetic resin or the laminated bimorph type displacement piece housed in the flexible metal case, the force generated by the bending causes the synthetic resin or the flexible resin on the side surface. Overcoming the elasticity of the metal wall, it is displaced as much as above. After that, when the application of the voltage is stopped, the output ends at both ends of the laminated bimorph displacement piece pressed by the elastic action of the synthetic resin or soft metal wall are restored.

Further, when the number of polarizations and the number of electrodes of the piezoelectric body are plural, a large number of bending vertices are formed in the plane of the bimorph type displacement piece when a voltage is applied. Therefore, at the output end having this apex as a support point, a force is generated by multiplying the force generated by the deflection having one apex by the number of apexes.

[0016]

Embodiments of the piezoelectric displacement element of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an embodiment, in which 1 is a bimorph type displacement piece. This bimorph displacement piece 1
Is 5 in the longitudinal direction, as shown in (a) of the enlarged view of FIG.
Polarized regions 2a, 2 having opposite positive and negative polarities in each of the divided regions.
The piezoelectric body 4 having the continuous electrodes 3, b, 2c, 2d, and 2e and the metal base plate 5 are bonded together with an organic adhesive. The bimorph displacement piece 1'is shown in FIG.
As shown in FIG. 5, the electrodes may be divided into 3a, 3b, 3c, 3d, and 3e without dividing the polarization region of the piezoelectric body 4. Furthermore, the bimorph displacement piece 1 "is shown in FIG.
As shown in (c), the two piezoelectric bodies 4a and 4b may be attached to each other at positions where the polarization directions are opposite to each other.

These bimorph type displacement pieces 1 are composed of the piezoelectric body 4 side and the piezoelectric body 4 side, or the base plate 5 side and the base plate 5 side.
After stacking 10 with the sides overlapping back to back,
It is stored in Case 6. On the upper part of the case 6, a metal plate 7 having high rigidity is placed, and then a cap 8 is fastened with a bolt 9. Two slide holes 10 are opened in the cap 8 and two rods 11 are inserted therein. Then, the output end 12 is provided outside, and the working plate 7 and the rod 1 are provided.
They are connected by 1. Further, one coned disc spring 13 is fitted on each rod 11, and the bimorph-type displacement pieces 1 stacked via the action plate 7 are pressed.

Now, a voltage is applied to the electrode 3 of the bimorph type displacement piece 1 of FIG. 2 (a) or to the electrodes 3a, 3b, 3c, 3d, 3e of the bimorph type displacement piece 1'of FIG. 2 (b) alternately. Two positive and negative voltages are applied, or two electrodes 3 based on the center electrode 3g of the bimorph type displacement piece 1 ″ of FIG.
When a voltage is applied to p and 3n, the bimorph displacement piece 1,
2'and 1'bend as shown in FIGS. 2 (a), (b), and (c), respectively. At that time, the bimorph-shaped displacement piece 1, or 1 ', or 1 "is the apex of the deformed deflection. And the vertices are laminated at the same position, a displacement amount obtained by multiplying the displacement of one bimorph type displacement piece 1, 1'or 1 "by 10 appears at the output end 12. Also, the vertices formed by bending The generated force doubles as the supporting points at several two points of the. And when the voltage applied to the bimorph type displacement pieces 1, 1 ', 1 "is removed, the restoring force of the disc spring 13 acts. The plate 7 returns to the position before the displacement.

Next, another embodiment of the present invention will be described. FIG. 3A shows a longitudinal sectional view of the embodiment. In the figure, reference numeral 1 denotes a bimorph type displacement piece, and ten bilayer displacement pieces are laminated so as to overlap back-to-back, as in the first embodiment. Then, at the both ends in the stacking direction of the stacked bimorph displacement pieces, 1
After applying the highly rigid metal working plates 7'one by one, a highly elastic thermoplastic synthetic resin is poured as a molding material,
The lining 14 is formed all around the surface. As a result, the surface of the lining 14 covering the working plate 7'becomes the output end 12 '.

Further, in FIG. 3B, ten bimorph displacement pieces 1 are laminated back to back in the same manner as above on a case 6'of a soft metal such as aluminum having a thick bottom portion. The upper part is covered with a cap 8'of a soft metal such as aluminum having a similar thickness and welded to the case 6'to seal it. As a result, the rigidity of the bottom surface portion of the case 6'and the cap 8'is increased, and the end face thereof becomes the output end 12 ".

In this embodiment, as in the first embodiment, when a voltage is applied to the electrode 3 of the bimorph displacement piece 1, the bimorph displacement piece 1 bends as shown in FIG. 2 (a). At this time,
Since the bimorph type displacement piece 1 is laminated so that the two vertices of the deflection generated by the deformation overlap with each other, the displacement amount obtained by multiplying the displacement of one bimorph type displacement piece 1 by 10
Double force appears at the output ends 12 ′ and 12 ″. Then, when the voltage applied to the bimorph displacement piece 1 is removed, the lining 14 located on the side surface of the bimorph displacement piece 1 or the wall surface of the case 6 ′. Output end 12 ', 1 by elastic restoring force
2 "returns to the position before displacement.

[0023]

As described above, according to the present invention, first, two piezoelectric bodies or bimorph type displacement pieces in which a piezoelectric body and a metal plate are laminated are laminated to generate a large displacement amount and an appropriate amount at the output end. I got power. Further, since the number of stacked layers is not large, the capacitance as a capacitor is small, and the element can be driven with high responsiveness.

Further, the laminated bimorph type displacement pieces can be molded with a highly elastic synthetic resin to form an integrated element, and the elasticity of the synthetic resin can restore the displacement of the output end.

Further, since the bimorph type displacement piece is divided and polarized, or the electrodes are divided and the positive and negative voltages are alternately applied to the respective electrodes, a plurality of displacement supporting points are generated and the generated force is increased.

[Brief description of drawings]

FIG. 1 shows a vertical cross section of a piezoelectric displacement element according to an embodiment of the present invention.

FIG. 2 shows the appearance of a bimorph type displacement piece that constitutes the piezoelectric displacement element of the present invention.

FIG. 3 shows a longitudinal section of a piezoelectric displacement element according to another embodiment of the present invention.

[Explanation of symbols]

 1, 1 ', 1 "Bimorph type displacement piece 2a, 2b, 2c, 2d, 2e Polarization region 3, 3a, 3b, 3c, 3d, 3e Electrode 4 Piezoelectric body 5 Base plate 6, 6' Case 7, 7 'Action Plate 8, 8'Cap 9 Bolt 10 Slide hole 11 Rod 12, 12 ', 12 "Output end 13 Disc spring 14 Lining

Claims (5)

[Claims] 1. A bimorph displacement piece in which two piezoelectric plates or a piezoelectric plate and a plate made of another material are bonded together, and a position where the apex and the apex of a flexure of the plurality of bimorph displacement pieces overlap each other. A case (container) that is stacked and stored in a stack, a pressure mechanism such as a spring that presses the stacked bimorph displacement piece in the stacking direction, and a displacement component that is interposed between the pressure mechanism and the stacked bimorph displacement piece. A piezoelectric displacement element comprising an output end for taking out the electric field, and integrating and taking out the displacement and the force generated when the bimorph type displacement piece to which a voltage is applied bends in the laminating direction. 2. Two rigid material plates are arranged at both ends of the laminated bimorph type displacement piece in the laminating direction, and the periphery of the laminated bimorph type displacement piece and the rigid material plate is molded integrally with a synthetic resin. Piezoelectric displacement characterized by integrating the displacement and force of a bimorph type displacement piece to which a voltage is applied to the plates of rigid material at both ends, and pressing the laminated bimorph type displacement piece with the elasticity of the molded synthetic resin. element. 3. Two rigid material plates are arranged or formed at both ends in the stacking direction of the stacked bimorph displacement pieces,
The laminated bimorph displacement pieces alone or together with the rigid material plates are housed in a case made of a flexible metal such as aluminum and integrated, and the displacement and force of the bimorph displacement pieces to which a voltage is applied are applied to the rigid material plates at both ends. A piezoelectric displacement element, characterized by integrating and pressing a laminated bimorph type displacement piece due to elasticity of a case wall. 4. The piezoelectric body is divided into a plurality of regions, adjacent regions of the respective regions are polarized in opposite directions, and when a voltage is applied to the piezoelectric body, the bimorph displacement piece has a flexure having a plurality of curvatures. 3. The piezoelectric displacement element according to claim 1, wherein the generated force is increased and the generated force is increased by the number of deflection peaks. 5. The piezoelectric electrode is divided into a plurality of regions, and voltages in opposite positive and negative directions are applied to adjacent regions of the respective regions to cause a bimorph type displacement piece to bend with a plurality of curvatures. 3. The piezoelectric displacement element according to claim 1 or 2, wherein the generated force is increased by the number of deflection peaks.