JPH02246384A - piezoelectric actuator - 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 (Field of Industrial Application) The present invention relates to a piezoelectric actuator, and particularly to a multilayer piezoelectric actuator that utilizes a piezoelectric transverse effect.

(Prior Art) FIG. 2 is a perspective view of essential parts showing an example of a conventional four-layer piezoelectric plate type piezoelectric actuator. This piezoelectric actuator
Then, gaps are formed between the electrodes on both sides of the outer piezoelectric plates 2a and 2d among the four stacked piezoelectric plates 2a, 2bl, 2C and 2d, and folded electrodes 3a, 3b, By forming 3c and 3d, each electrode of the intermediate layer is drawn out to the outer surface.

(Problem H to be solved by the invention) In the piezoelectric actuator 1 shown in FIG.
, 4b and 4C, each electrode is taken out to the outside, making it difficult to take out the electrode.

Furthermore, in the conventional example shown in FIG. 2, since bipolar electrodes are present on the outer surface, it is not possible to hold the ends of the piezoelectric plate by sandwiching them between metal pieces from above and below.

Therefore, the length of the piezoelectric plate cannot be used effectively, and even if it is sandwiched between insulators, space is required at the end of the piezoelectric plate to take out the electrode, so the length of the piezoelectric plate cannot be used effectively. Therefore, the main object of the present invention is to provide a piezoelectric actuator whose electrodes can be easily taken out and which can be reliably held at the ends.

(Means for Solving the Problems) The present invention is a piezoelectric actuator in which a piezoelectric body made by bonding together two piezoelectric plates each having electrodes formed on their bidirectional surfaces is bonded to each bidirectional surface of a plate-shaped shim. The shim includes two metal plates spaced apart in the plane direction, and the electrode of the piezoelectric material facing the shim is in contact with one of the metal plates, and the electrode of the intermediate layer of the piezoelectric material is connected to the other metal plate. This is a piezoelectric actuator in which a folded electrode is formed on the surface of a piezoelectric plate, extending to a portion facing a metal plate.

(Function) The electrode of the piezoelectric material facing the shim is taken out by one metal plate. Further, the electrode of the intermediate layer of the piezoelectric body is taken out by the other metal plate via the folded electrode.

Therefore, the bipolar electrodes no longer exist on the amphiphilic surface of the piezoelectric actuator.

(Effect of the invention) According to this invention: 1. Since there are no bipolar electrodes on the main surface of the piezoelectric actuator, it can be held by sandwiching the ends of the piezoelectric plate between metal pieces that also serve as terminals.

Therefore, it becomes easy to take out the electrodes of the piezoelectric actuator. Moreover, since it is possible to hold the piezoelectric plate at its end, the length of the piezoelectric plate can be used effectively.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIGS. 1A and 1B each show an embodiment of the present invention, with FIG. 1A being an exploded perspective view of the main part thereof, and FIG. 1B being a perspective view of the main part thereof.

This piezoelectric actuator 10 includes two metal plates 12 and 14 as shims, one metal vi, x2 is
For example, it is formed into a rectangular shape, and at one longitudinal end,
A projecting piece 12a extending in the longitudinal direction is formed, and further,
A rectangular notch 12b is formed on one side of one end in the longitudinal direction.

Further, the other metal plate 14 has a notch 12b of the metal plate 12.
It is formed into a slightly smaller rectangular shape, and a projecting piece 14a is formed at the lower end. This metal plate 14 is the metal plate 1
The metal plate 12 is spaced apart from the metal plate 12 in the notch 12b of the metal plate 12 in the plane direction.

In this case, the metal plates 12 and 14 are
a and 14a are arranged so as to face the same direction.

Furthermore, a piezoelectric material 16 is bonded to one main surface of these metal plates 12 and 14. This piezoelectric body 16 includes two stacked piezoelectric plates 18 and 20, and electrodes 1 are provided on the bidirectional surfaces of these piezoelectric plates 18 and 20, respectively.
8a, 18b and 20a, 20b are formed. In this case, in particular, the electrode 18a facing the metal plates is formed so as to face only one metal plate 12. Therefore, this electrode 18a is electrically connected to one metal plate 12.

Furthermore, a folded electrode 19 is formed on one end surface of the piezoelectric plate 18 on the metal plate side and on the surface facing the metal plate, extending from the electrode 18b to the portion facing the other metal plate 14. Therefore, the folded electrodes 19 electrically connect the electrodes 18b and 20a of the intermediate layer of the piezoelectric body 16 to the other metal plate 14. Note that the folded electrode 19 is similar to the electrode 18a.
It is formed together with the electrode 18a by a method such as etching or printing so as not to be electrically conductive with the electrode 18a.

On the other hand, another piezoelectric body 22 is bonded to the other main surface of the metal plates 12 and 14 as well. This piezoelectric body 22 has a symmetrical structure with the piezoelectric body 6 and includes two piezoelectric plates 24 and 26 that are laminated like the piezoelectric body 16. These piezoelectric plates 2
Electrodes 24a, 24b and 26a, 26b are also formed on the bidirectional surfaces of 4 and 26, respectively. in this case,
The electrode 24a facing the metal plate is formed so as to face only one metal plate 12. Furthermore, a folded electrode 25 is formed on the piezoelectric plate 24 on the metal plate side from the electrode 24b to the portion facing the other piezoelectric plate 14. The folded electrode 25 is formed together with the electrode 24a by, for example, etching or printing so as not to be electrically conductive with the electrode 24a. Therefore, in this piezoelectric body 22, the electrode 24a facing the metal plates is placed on one metal plate 12, and the electrode 24b on the intermediate layer is placed on one metal plate 12.
and 26a are electrically connected to the other metal plate 14, respectively.

In this piezoelectric actuator 10, in order to utilize the piezoelectric transverse effect, for example, the piezoelectric plates 18 and 20 are bonded together so that their polarization directions are opposite, and conversely, the piezoelectric plates 24 and 26 are bonded together so that their polarization directions are opposite to each other. It is pasted like this.

In this piezoelectric actuator 10, the first metal plate 12 and the piezoelectric body 1 are connected by the metal pieces 28 and 30 as terminals.
6 and 22 can be connected to the outer electrodes 20b and 26b. That is, the metal piece 28 includes a rectangular connecting piece 28a, and this connecting piece 28a is adhered to the electrode 20b of the piezoelectric body 16. Further, a crank-shaped pull-out piece 28b is formed at the end of the connecting piece 28a and extends from there to the protruding piece 12a of the first metal plate 12. Similarly, the metal piece 30 also includes a rectangular connecting piece 30a, and this connecting piece 30a is adhered to the electrode 26b of the piezoelectric body 22. Furthermore, the protruding piece 12 of the metal plate 12 is connected to the end of the connecting piece 30a.
A crank-shaped pull-out piece 30b extending in the direction a is formed. Therefore, in this piezoelectric actuator 10, the electrodes can be easily taken out.

Moreover, in this piezoelectric actuator lO, the metal piece 28
Since the piezoelectric plate can be held by the pull-out pieces 28b and 30b, ie, by the ends of the piezoelectric plate, the length of the piezoelectric plate can be effectively utilized.

In addition, in the above-mentioned embodiment, the notch 1 of one metal plate 12
2b and the other metal plate 14 are each formed into a rectangular shape, but they may be formed into other shapes such as a circular shape. Further, the shapes of the folded electrodes and metal pieces may also be changed.

[Brief explanation of drawings]

FIG. 1A and FIG. 1B each show an embodiment of the present invention, with FIG. 1A being an exploded perspective view of the main part thereof, and FIG. 1B being a perspective view of the main part thereof. FIG. 2 is a perspective view of essential parts showing an example of a conventional four-layer piezoelectric plate type piezoelectric actuator. In the figure, lO is a piezoelectric actuator, 12 and 1
4 is a metal plate, 16 and 22 are piezoelectric bodies, 18.20.2
4 and 26 are piezoelectric plates, 18a. i8b, 20a, 20b, 24a, 24b, 26a and 26b are electrodes, and 19 and 25 are folded electrodes. Figure 1A Patent Applicant Murata Manufacturing Co., Ltd. Representative Patent Attorney Oka 1) Kei Zen

Claims (1)

[Scope of Claims] A piezoelectric actuator in which a piezoelectric body made by bonding two piezoelectric plates having electrodes formed on both principal surfaces is bonded to both principal surfaces of a plate-shaped shim, the shim being two metal plates arranged at a distance in the plane direction, the electrode of the piezoelectric body facing the shim is in contact with one of the metal plates, and the electrode of the intermediate layer of the piezoelectric body is connected to the other metal plate; A piezoelectric actuator, wherein a folded electrode is formed on a surface of the piezoelectric plate, extending to a portion facing the metal plate.