JP2504142B2 - Piezoelectric actuator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric actuator, and more particularly to a multi-layer type piezoelectric actuator utilizing the piezoelectric lateral effect.

(Prior Art) FIGS. 3 to 5 are perspective views of essential parts showing an example of a conventional piezoelectric actuator of a four-layer piezoelectric plate type.

In the piezoelectric actuator 1 shown in FIG. 3, of the four laminated piezoelectric plates 2a, 2b, 2c and 2d, notches are formed at the ends of the outer piezoelectric plates 2a and 2d, and leads are formed at the notches. By soldering the wires 3, the electrodes between the outer piezoelectric plates 2a and 2d and the inner piezoelectric plates 2b and 2c are pulled out.

In the piezoelectric actuator 1 shown in FIG. 4, gaps are formed in the electrodes on both sides of the outer piezoelectric plates 2a and 2d, and the folded electrodes 4a, 4b, 4c and 4d are formed therein with, for example, a conductive resin material. , The electrodes of the intermediate layer are drawn to the outer surface.

Further, in the piezoelectric actuator 1 shown in FIG. 5, through holes 5 are provided in the outer piezoelectric plates 2a and 2d, and the electrode of the intermediate layer is drawn out to the outer surface through the through holes 5.

(Problems to be Solved by the Invention) In the piezoelectric actuator shown in FIG. 3, if the shape of the notch is small, the workability of soldering the lead wire is deteriorated, and the strength of the connecting portion of the lead wire is weakened, resulting in durability. On the contrary, if the shape of the notch is large, the holding at the end becomes unstable, so that the effective length of the piezoelectric plate or the piezoelectric body cannot be effectively obtained. Furthermore, it is difficult to take out the electrodes because there are many places where the electrodes are taken out.

Also, in the piezoelectric actuator shown in FIGS. 4 and 5, repeated expansion and contraction of the piezoelectric plate or the piezoelectric body causes
There is a problem in durability because the wire may be broken at a portion where a conductive resin material is used or a through hole portion. Further, in the piezoelectric actuator shown in FIGS. 4 and 5, since the electrodes of both electrodes are present at the ends of the main surface, there are many electrode extraction points and it is not possible to hold the electrodes at the ends. The effective length of the plate or the piezoelectric body cannot be effectively taken.

Therefore, the main object of the present invention is excellent in durability, the electrode can be easily taken out, and the electrode can be surely held at the end, and the effective length of the piezoelectric body can be effectively taken. It is to provide an actuator.

(Means for Solving the Problem) The present invention relates to a piezoelectric body in which two piezoelectric plates having electrodes formed on both entire surfaces are bonded together, and two piezoelectric plates having electrodes formed on both entire surfaces are bonded together. Another piezoelectric body is a piezoelectric actuator bonded to each surface of a metal plate, and the piezoelectric plate on the metal plate side of the two piezoelectric plates forming the piezoelectric body and another piezoelectric body are By forming a notch in the metal plate and the piezoelectric plate on the metal plate side of the two piezoelectric plates constituting the metal plate, and inserting a metal piece into the notch, the two piezoelectric plates constituting the piezoelectric body are attached to each other. This is a piezoelectric actuator in which an electrode formed on a combined surface and an electrode formed on a surface on which two piezoelectric plates constituting another piezoelectric body are attached to each other are drawn out.

(Operation) An electrode formed on a surface where two piezoelectric plates constituting a piezoelectric body are bonded to each other and two piezoelectric plates constituting another piezoelectric body are bonded to each other by a metal piece. The electrodes formed on the surface are taken out. Therefore, the electrodes of both polarities do not exist on the main surface of the piezoelectric actuator.

(Effects of the Invention) According to the present invention, since the conductive resin material and the through-hole unlike the conventional example are not used, the durability of the piezoelectric actuator can be ensured. Moreover, since the electrodes of both electrodes do not exist on the main surface of the piezoelectric actuator, it is easy to take out the electrodes, and it is easy to hold the electrodes at the ends, and
The effective length of the piezoelectric body can be effectively taken.

Furthermore, an electrode formed on a surface where two piezoelectric plates constituting a piezoelectric body are bonded to each other by one metal piece, and two piezoelectric plates constituting another piezoelectric body are bonded to each other. Since the electrodes formed on the surface are taken out, the number of parts can be reduced and the manufacturing process can be simplified. Therefore, the cost can be reduced.

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

(Embodiment) FIG. 1 and FIG. 2 respectively show an embodiment of the present invention, FIG. 1 is a perspective view of a main portion thereof, and FIG. 2 is an exploded perspective view of the main portion thereof.

The piezoelectric actuator 10 includes, for example, a strip-shaped shim 12 made of a metal plate. A projecting piece 12a extending in the longitudinal direction is formed on one end side of the shim 12 in the longitudinal direction. Furthermore, a rectangular notch 13 is formed at the center of one end of the shim 12 in the longitudinal direction.

A piezoelectric body 14 is attached to one main surface of the shim 12.
The piezoelectric body 14 includes two laminated piezoelectric plates 16 and 18, and electrodes 16a, 16b and 18a, 18b are formed on both main surfaces of the piezoelectric plates 16 and 18, respectively. Further, the piezoelectric plate 16 on the one main surface side of the shim 12 is provided with a rectangular notch 17 at the center of one end in the longitudinal direction, like the shim 12.

On the other hand, another piezoelectric body 20 is attached to the other main surface of the shim 12. Similar to the piezoelectric body 14, this other piezoelectric body 20 also includes two piezoelectric plates 22 and 24 that are stacked, and the electrodes 22a, 22b and 24a, 24a, 24b
Are formed respectively. The piezoelectric plate 22 on the other principal surface side of the shim 12 also has a rectangular notch 23 formed at the center of one end in the longitudinal direction.

Therefore, a rectangular parallelepiped notch 26 is formed by the notches 13, 17 and 23 between the outer piezoelectric plates 18 and 24. Then, a metal piece or a terminal 28 having a contact piece 28a having a bellows structure having a substantially M-shaped cross section, for example, is inserted and fixed in the notch 26. In this case, the terminal 28 includes the electrodes 18a and 24a inside the piezoelectric plates 18 and 24 with the protrusions of the contact piece 28a outside.
Is inserted and fixed in the notch 26 so as to contact the. In addition, in order to fix the terminal 28 in the notch 26, the contact piece
It is performed by adhering 28a and the electrodes 18a and 24a at the contact portions, or by filling the notch 26 with an insulating material.

In this piezoelectric actuator 10, in order to utilize the piezoelectric lateral effect, for example, the piezoelectric plates 16 and 18 are bonded so that their polarization directions face each other, and conversely, the piezoelectric plates 22 and 24 have their polarization directions opposite to each other. Are stuck together.

Further, external terminals 30 and 32 are connected to the electrodes 18b and 24b on the outside of the piezoelectric plates 18 and 24 on the outside, respectively. That is, the external terminal 30 includes a rectangular connection piece 30a, and the connection piece 30a is bonded to the electrode 18b of the piezoelectric plate 18. Further, a crank-shaped pull-out piece 30b extending from the connecting piece 30a to the projecting piece 12a of the shim 12 is formed at the end of the connecting piece 30a. Similarly, the external terminal 32 includes a connection piece 32a adhered to the electrode 24b outside the piezoelectric plate 24, and the connection piece 32a.
A crank-shaped pull-out piece 32b extending to the protruding piece 12a of the shim 12 is also formed at the end of the.

In this piezoelectric actuator 10, since the inner electrode is taken out by one terminal 28, one pole electrode exists on both main surfaces. Therefore, the piezoelectric bodies 14 and 20 can be held at the ends, and the lengths of the piezoelectric bodies 14 and 20 can be effectively utilized.

Further, since the electrodes are taken out at two places with one terminal 28, the number of parts for taking out the electrodes is reduced.

Further, since the electrodes are taken out by the terminals (metal pieces) 28, 30 and 32, the breaking motion is not caused by the expansion and contraction movement of the piezoelectric bodies 14 and 20, and the durability can be secured.

In the above-described embodiment, the terminal having the contact piece having a substantially M-shaped cross section is used, but the terminal has a shape connected to the internal electrode in the notch, for example, a substantially U-shaped cross section. Those having a contact piece of may be used,
The shape can be changed arbitrarily. Also, the shape of the external terminal may be changed arbitrarily.

[Brief description of drawings]

1 and 2 respectively show an embodiment of the present invention. FIG. 1 is a perspective view of a main part thereof, and FIG. 2 is an exploded perspective view of the main part thereof. 3 to 5 are perspective views of relevant parts showing an example of a conventional piezoelectric actuator which is the background of the present invention. In the figure, 10 is a piezoelectric actuator, 12 is a shim, 14 and 20 are piezoelectric bodies, 16, 18, 22 and 24 are piezoelectric plates, 16a, 16b,
18a, 18b, 22a, 22b, 24a and 24b are electrodes, 26 is a notch, 28 is a terminal, and 30 and 32 are external terminals.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Makino 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (56) References JP 54-87087 (JP, A) 64-48061 (JP, U)

Claims (1)

(57) [Claims] 1. A piezoelectric body in which two piezoelectric plates each having electrodes formed on both surfaces thereof are bonded together, and another piezoelectric body in which two piezoelectric plates each having electrodes formed on both surfaces are bonded together. A piezoelectric actuator bonded to each surface of a metal plate, wherein a piezoelectric plate on the side of the metal plate of two piezoelectric plates forming the piezoelectric body and two piezoelectric plates forming the other piezoelectric body By forming a notch in the piezoelectric plate on the metal plate side of the piezoelectric plate and the metal plate, and by inserting a metal piece in the notch,
An electrode formed on a surface on which the two piezoelectric plates constituting the piezoelectric body are bonded to each other, and an electrode formed on a surface on which the two piezoelectric plates constituting the other piezoelectric body are bonded to each other, Piezoelectric actuator in which the electrodes that are present are pulled out.