JPH04167579A - Electrostrictive effect element and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrostrictive element and a method for manufacturing the same.

[Conventional technology]

An electrostrictive element is an element that converts electrical energy into mechanical energy by utilizing the electrostrictive effect of a solid. Specifically, electrodes such as metal films are formed on opposing surfaces of a solid that has a large electrostrictive effect, and the strain in the solid that occurs when a potential difference is applied between the electrodes is utilized. Since the strain that occurs parallel to the electric field, that is, the longitudinal effect strain, is generally larger than the strain that occurs in the perpendicular direction, that is, the transverse effect strain, the energy conversion efficiency is higher when the former is used. In an electrostrictive element that utilizes this longitudinal effect with high energy conversion efficiency, the distortion generated increases as the electric field strength increases, so in order to obtain a large amount of displacement, it is necessary to increase the applied voltage so that the electric field strength does not decrease. is necessary. However, increasing the voltage requires a large and expensive power source, which also increases the risk of handling.

In order to improve the above drawbacks, an integrated multilayer ceramic capacitor type structure has been proposed. This structure is shown in FIGS. 5<a> and 5(b).

In FIG. 5(a), an internal electrode 2a is placed inside the electrostrictive effect 1.
, 2b are formed with a certain spacing, and the external chambers [
It is electrically connected to i3a and 3b.

The interval between the internal electrodes 2a and 2b can be set to about several tens of micrometers using ordinary chip capacitor technology. If this structure is adopted, the distance between the electrodes becomes narrower, so an electrostrictive effect element using the longitudinal effect that can be driven at a low voltage can be realized.

[Problems to be Solved by the Invention] As is clear from the projection view of FIG. 5(b) in the above-mentioned conventional electrostrictive effect element, the part where the internal electrodes overlap (4 is the central rectangular part) is the element. It is small compared to the cross-sectional area of . Therefore, when a voltage is applied to these opposing electrodes, the overlapping parts of the internal electrodes deform according to the electric field, but the parts where the electrodes do not overlap and the parts without electrodes do not deform. Stress concentration occurs. In particular, when a high voltage is applied to extract a large amount of displacement or when the internal electrodes are made of multiple layers, large stress concentration occurs and mechanical breakage is likely to occur.

An object of the present invention is to eliminate the drawbacks of the conventional electrostrictive effect element and to provide an electrostrictive effect element having a structure that disperses stress concentration and prevents mechanical destruction even when the internal electrodes are multilayered in an attempt to obtain a large displacement. The goal is to provide the following.

[Means to solve the problem]

In the electrostrictive effect element of the first aspect of the present invention, electrostrictive materials and internal electrodes are alternately laminated, and each internal electrode is electrically connected to two external electrodes facing each other every other layer. In an electrostrictive effect element, the internal electrode is exposed only on two opposing surfaces for connection to each external electrode, and after the electrostrictive material and internal electrode are laminated and integrated, the exposed surface of the internal electrode is exposed. After constructing a reference laminate with two external electrodes facing each other, stacking several reference laminates with their external electrode surfaces aligned and mechanically connecting one point in the center of the dowel with adhesive. , and has a structure in which the respective external electrodes of the reference laminate are electrically connected.

Further, the method for manufacturing an electrostrictive effect element according to the second aspect of the present invention includes a step of exposing internal electrodes only on two opposing surfaces and forming a reference laminate in which external electrodes are formed on the exposed surfaces;
The method includes the steps of stacking a plurality of external electrodes on the reference laminate and mechanically connecting one point approximately in the center of each with an adhesive, and electrically connecting each of the external electrodes of the reference laminate. It is composed of the following characteristics.

〔Example〕

Next, the present invention will be explained with reference to the drawings. 1(a>, (b) are a perspective view and a sectional view thereof showing an electrostrictive effect element according to an embodiment of the present invention, and FIG. 2(a>
, (b), and 3 are process explanatory diagrams for explaining the manufacturing method of one embodiment of the present invention, and FIGS. 2(a) and (b) are sectional views and sectional views of the process of cutting the laminate, respectively. Perspective view, 2nd
Figure (c) is a cross-sectional view of the reference laminate after cutting, Figure 2 (d)
FIG. 2 is a cross-sectional view of the reference laminate after firing and forming external electrodes. The method for manufacturing an electrostrictive element is to finely powder a ceramic material exhibiting an electrostrictive effect such as lead zirconate titanate, add an organic binder, a solvent, and a plasticizer, knead it, and then process it into a powder of approximately 130 μm using a doctor blade method. Create a thick raw sheet. Next, the inner chamber is created by screen printing on the surface of this raw sheet! 2, three to four sheets are stacked and thermocompression bonded to form a laminate 5 in which the internal molds fi2 are alternately shifted as shown in FIG. 2(a).

Next, as shown in FIG. 2(b), the rotary cutting blade 21 moves vertically while horizontally moving the laminate 5 to a cutting position 22.
By sequentially cutting and firing, a reference laminate 6 as shown in FIG. 2(C) is obtained. Here, a paste made of a substance for improving the bond between the metal powder mainly composed of silver, the glass frit, and the ceramic is applied to both end faces of this reference laminate 6 and baked, as shown in FIG.
A reference laminate 6 having a so-called multilayer ceramic capacitor element structure as shown in d) is obtained.

Furthermore, as shown in FIG. 3, a plurality of these reference laminates 6,
The three surfaces of the external electrodes are aligned and overlapped, and an epoxy adhesive 7 is applied to the substantially central portion of the external electrodes to connect them together.

Next, each of the external electrodes of the reference laminate 6 is connected with a thin metal lead wire to each of the facing external electrodes 3 using conductive resin or soldering.
The electrostrictive effect element of the present invention as shown in >, (b,) is obtained.

FIG. 4 shows a perspective view of a second embodiment of the present invention. The construction method is generally the same as in Example 1, but the external electrodes 3 are connected using a plurality of thin metal lead wires 8. This allows the electrical resistance value to be reduced and an electrostrictive effect element with low loss to be produced. The advantage is that you can get it.

〔Effect of the invention〕

As explained above, according to the present invention, the electrostrictive effect element has a structure in which a plurality of reference laminates 6 are connected approximately in the center with an adhesive 7, so that even when a voltage is applied, the internal electrodes The stress concentration in the deformable portion 4 where the internal electrodes 2 overlap and the non-deformable portion without the internal electrode 2 is also absorbed by the reference laminate 6 for only 3 to 4 layers, and the electrostrictive effect element as a whole is mechanically This has the effect of providing an electrostrictive element that can handle a large amount of displacement without causing damage.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are perspective views and cross-sectional views showing an electrostrictive effect element according to an embodiment of the present invention, FIGS. 2(a) to (d),
FIG. 3 is a process explanatory diagram for explaining a manufacturing method according to an embodiment of the present invention, and FIGS. Figure (C) is a sectional view of the standard laminate after cutting, Figure 2(d) is a sectional view of the standard laminate after forming the firing postelectrode, and Figure 3 is a sectional view of the standard laminate after being cut. 4 is a cross-sectional view after the reference laminate is connected with an adhesive; FIG. 4 is a perspective view of an electrostrictive element according to another embodiment of the present invention; and FIG. a)
, (b) are a cross-sectional view of a conventional electrostrictive effect element and a perspective plan view of an internal electrode. 1... Electrostrictive material, 2.2a, 2b... Internal electrode, 3
゜3a, 3b... External electrode, 4... Overlapping portion of internal electrode, 5... Laminated body, 6... Reference laminate, 7...
・Adhesive, 8... Lead wire, -21... Cutting blade, 2
2... Cutting position.

Claims (2)

[Claims] 1. In an electrostrictive element in which a material exhibiting an electrostrictive effect and internal electrodes are alternately laminated, and each internal electrode is electrically connected to two external electrodes facing each other every other layer, In order to connect the internal electrode to an external electrode provided facing each other, a material exhibiting a strain effect and the internal electrode are laminated and integrated so as to be exposed alternately only on two opposing surfaces, and the internal electrode is exposed. forming a reference laminate by forming external electrodes on two opposing surfaces,
A plurality of the reference laminates are stacked with their external electrode surfaces aligned, and a point approximately in the center of each of the reference laminates is mechanically connected using an adhesive, and the external electrodes of each of the reference laminates are connected on each opposing surface. An electrostrictive effect element characterized in that it is electrically connected to. 2. The internal electrodes are exposed only on two opposing surfaces,
a step of creating a reference laminate with an external electrode formed on its exposed surface; a step of overlapping a plurality of the reference laminates with external electrodes and mechanically connecting one point in the approximate center of each with an adhesive; 1. A method for manufacturing an electrostrictive element, comprising the step of electrically connecting external electrodes of each reference laminate.