JPH02246385A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To facilitate extraction of electrodes and to effectively hold at ends by bringing electrodes of a piezoelectric unit opposed to a shim into contact with one metal plate, and electrically connecting the electrode of the intermediate layer of the unit to the other metal plate with a conductive material. CONSTITUTION:A shim has two metal plates 12, 14 disposed at an interval in a planar direction, the electrodes of piezoelectric units 16, 22 opposed to shims are brought into contact with one plate 12, and the electrodes 18b, 20a of the intermediate layers of the units 16, 22 are electrically connected to the other metal plate 14 with a conductive material. Thus, electrodes of both polarities do not exist on both main faces 20b, 26b of a piezoelectric actuator 10. Accordingly, the ends of the plates 16, 22 are interposed by metal piece 28, 30 used also as terminals to be held. Thus, the extraction of the electrodes of the actuator 10 is facilitated, and the plates 16, 22 can be held at the ends. Accordingly, the lengths of the plates 16, 22 can be effectively utilized.

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
Now, notches 3 are formed at the ends of the outer piezoelectric plates 2a and 2d among the four layers of piezoelectric plates 2a, 2b, 2c, and 2d to be laminated, and the lead wires 4 are soldered to the notches 3. Possibly the outer piezoelectric plates 2a and 2
The electrodes between d and the inner piezoelectric plates 2b and 2C are drawn out.

(Problems to be Solved by the Invention) In the piezoelectric actuator 1 shown in FIG. 2, if the shape of the notch 3 is small, the soldering workability of the lead wire 4 will be poor, making it difficult to take out the electrode, and the lead wire The strength of the connection part 4 is weakened, resulting in poor durability. On the other hand, if the shape of the notch 3 is large, the length of the piezoelectric plate cannot be effectively secured because the holding at the end becomes unstable.

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 gym 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 and the other metal plate are in contact with each other. The piezoelectric actuator is electrically connected to a metal plate through a conductive material.

(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 conductive material.

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

(Effects of the Invention) According to the present invention, since there are no bipolar electrodes on the main surface of the piezoelectric actuator, the piezoelectric plate 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 IO includes two metal plates 12 and 14 as shims. One of the metal plates 12 is formed into a strip shape, for example, and has a protruding piece 12a extending in the longitudinal direction formed at one end of the longitudinal direction, and a rectangular notch at one end of the longitudinal direction. 12b is formed.

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 one 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 piezoelectric plates 18 and 20 that are laminated, the piezoelectric plate 18 on the metal plate side is formed so that one end surface in the longitudinal direction thereof is inclined, and the piezoelectric plate 20 includes four piezoelectric plates 18 and 20. The length in the longitudinal direction is formed to be slightly shorter than the piezoelectric plate 18. Further, on the bidirectional surfaces of these piezoelectric plates 18 and 20, respectively,
Electrodes 18a, 18b and 20a, 20b are formed. In this case, in particular, the electrode 18a facing the metal plate is formed on one metal plate 1 by etching, printing or the like.
It is formed so as to face only 2. Therefore, this electrode 18a is electrically connected to one metal plate 12.

Note that this electrode 18a is formed so as not to be electrically connected to the other metal plate 14.

An electrode 18 is provided on one end surface of the piezoelectric plate 18 on the metal plate side.
A conductive material 21 such as a conductive resin or a conductive adhesive is applied in a band shape from b to the other metal plate 14 . Therefore, the conductive material 21 electrically connects the electrodes 18b and 20a of the intermediate layer of the piezoelectric body 16 to the other metal plate 14.

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 is similar to the piezoelectric body 1
6, and includes two piezoelectric plates 24 and 26 laminated in the same way as the piezoelectric body 16, and the piezoelectric plate 24 on the metal plate side is formed so that one end surface in the longitudinal direction is inclined. , the piezoelectric plate 26 is formed slightly shorter than the piezoelectric plate 24. Electrodes 24a, 24b and 26a, 26b are also formed on both sides of these piezoelectric plates 24 and 26, respectively. In this case, the electrode 2 facing the metal plate
4a is formed, for example, by etching or printing, so as to face only one metal plate 12 so as not to be electrically conductive with the other metal plate 14.

Furthermore, an electrode 24 is provided on one end surface of the piezoelectric plate 24 on the metal plate side.
A conductive material 27 such as conductive resin or conductive adhesive is applied from b to the other piezoelectric plate 14 .

Therefore, in this piezoelectric body 22 as well, the electrode 24a facing the metal plates is electrically connected to one metal plate 12, and the intermediate layer electrodes 24b and 26a are electrically connected to the other metal plate 14.

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 lO, 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. Furthermore, since the electrode is taken out as a metal plate and a metal piece, durability is improved compared to the conventional example.

Moreover, in this piezoelectric actuator 10, 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
Although 2b and the other metal plate 14 are each formed into a rectangular shape, they may be formed into other shapes such as a circular shape, and the shape of the metal piece 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, 10 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. 18b, 20a, 20b, 24a, 24b, 26a and 26b are electrodes, and 21 and 27 are conductive materials. 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 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 in contact with the other metal plate. The piezoelectric actuator is electrically connected to the metal plate through a conductive material.