JPH0346380A - Piezoelectric element of easy lamination - Google Patents

Abstract

PURPOSE:To ensure easy connection of a substrate and an electrode of each piezoelectric element piece by providing a reference mark for lamination registration to a side of each piezoelectric element. CONSTITUTION:A piezoelectric element Q is integrally formed by laminating and bonding piezoelectric element piece q1 to qn and a substrate (r) on a rough ring having a specified thickness. In this case, a reference mark (m) for lamination registration is provided to a side of each of piezoelectric element pieces q1 to qn. A side section of an insulation side and that of an electrode side are made to align up and down alternatively by alignment of the reference mark (m) for lamination registration in vertical direction. Thereby, it is possible to laminate all the piezoelectric pieces very readily.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a piezoelectric element that can be used in a laminated piezoelectric actuator and the like and can be easily manufactured.

(B) Prior Art Conventionally, as one form of piezoelectric actuator, there is a laminated type piezoelectric actuator constructed by laminating and bonding a plurality of piezoelectric element pieces with an adhesive such as silver paste.

That is, as shown in FIG. 11, the plurality of piezoelectric element pieces 51 are laminated and bonded on the insulating side portions 51a provided on sides of each piezoelectric element piece 51 facing each other by about 180 degrees.
This is done by laminating and adhering the and electrode side portions 51b so that they are alternately aligned in the vertical direction, and laminating and adhering them to the substrate 54, and then using conductive adhesives 52 and 53. Conductive adhesives 52 and 53 are applied along 180-degree opposing sides of the stacked piezoelectric element assembly to connect the electrodes of each piezoelectric element to the substrate 54.

(c) Problems to be Solved by the Invention However, the piezoelectric element described above still has the following problems.

■ As described above, when stacking a plurality of piezoelectric element pieces 51, the insulating side side portions 51a and electrode side side portions 51b provided on sides of each piezoelectric element piece 51 that are approximately 180 degrees opposite each other alternately in the vertical direction. However, when doing this manually, alignment is difficult.

■ Also, since positioning is difficult, insulating side portions 51a are provided on sides of each piezoelectric element piece 51 that are approximately 180 degrees opposite each other.
and the electrode-side side portions 51b cannot be made to appear aligned in the vertical direction alternately, and the subsequent conductive adhesive material 52.
53 becomes difficult, and reliable connection between the substrate 54 and the electrodes of each piezoelectric element piece 51 cannot be ensured.

An object of the present invention is to provide a piezoelectric element that can be easily stacked and can solve the above problems.

(d) Means for Solving the Problems The present invention provides a piezoelectric element in which a plurality of piezoelectric element pieces are laminated with a conductive adhesive interposed between them, and a fiducial mark for lamination alignment is provided on the side surface of each piezoelectric element piece. and by vertically aligning the reference marks for lamination positioning, the insulating side side portion and the electrode side side portion provided on the side surface of each piezoelectric element piece were aligned alternately in the vertical direction. The present invention relates to a piezoelectric element that can be easily stacked.

(E) Functions and Effects ■ In the present invention, with the above-described configuration, when piezoelectric element pieces are laminated, each piezoelectric element is automatically aligned by simply aligning the reference marks for lamination positioning provided on each piezoelectric element piece. The insulating side portions and the electrode side portions provided on the side surfaces of the pieces can be alternately aligned in the vertical direction.

Therefore, the work of laminating all the piezoelectric element pieces can be performed extremely easily.

■Also, by aligning the reference marks for lamination alignment, the insulating side and electrode side parts provided on the side surfaces of each piezoelectric element piece are aligned alternately in the vertical direction, so the insulating side The side portions and the electrode side portions can be accurately aligned alternately in the vertical direction.

Therefore, the work of applying the conductive adhesive can be easily performed, and the connection between the substrate and the electrodes of each piezoelectric element piece can be easily and reliably performed.

(F) Embodiment An embodiment of the present invention is shown in FIGS. 1 to 3, in which piezoelectric element pieces q1 to q each have a substantially ring shape and have a predetermined thickness.
An integral piezoelectric element Q is constructed by laminating and adhering n and a base Fir.

In the piezoelectric element Q that is laminated and bonded together in this way,
The conductive adhesive p interposed between the piezoelectric element pieces q l = q n can be used as an electrode.

That is, as shown in FIG. 2, a conductive adhesive P such as silver paste is applied to both surfaces of each piezoelectric element piece 91 to qn using a method such as screen printing. forming a pattern.

This pattern consists of an insulating part At that is coated with an insulating adhesive pr of a predetermined width from the outer periphery of each piezoelectric element piece 91 to qn, an adhesive part pc that is coated with a conductive adhesive p on the inside thereof, and the same adhesive part pc. It is formed of an extended portion pa coated with a conductive adhesive p that reaches the outer peripheral edge of each piezoelectric element piece 91 to qn.

The above-mentioned extension part pa is coated on both sides of each piezoelectric element piece q1 to qn, but the positions on the front and back sides are different from each other.
For example, 180' are different from each other.

Then, the piezoelectric element pieces ql=qn are stacked with the extending parts pa facing each other and the insulating parts At facing each other, and these piezoelectric element pieces 9
1 to qn are laminated on a base Fir coated with a conductive adhesive p, and bonded under pressure to form an integrated piezoelectric element Q.

Note that the adhesive part pc and the extension part pa can be formed on the piezoelectric element pieces q1 to qn at the same time as the conductive adhesive material p of the adhesive part pc by a method such as screen printing, and the insulating part At
Similarly, it can be formed by a method such as screen printing.

A conductive adhesive pl for drawing out is applied to the outside of the extension part pa on the outer surface of the piezoelectric element Q stacked in this way, and each conductive adhesive p is connected to the terminal W provided on the substrate r. It is conducting.

In addition, the electrodes of each piezoelectric element piece 91 to qn are stacked with the extensions pa of the conductive adhesive p facing each other, so that every other electrode is connected to one terminal W in parallel. , the remaining electrodes are connected to the other terminal W so that a voltage can be applied to each piezoelectric element piece Ql""-'Qn.

In the above configuration, the present invention further provides, as shown in FIGS. 1 to 3, a reference mark m for lamination alignment on the side surface of each piezoelectric element piece q1 to qn, and a reference mark m for lamination alignment. A configuration is provided in which the insulating side side portions S and electrode side side portions S2 provided on the side surfaces of each piezoelectric element piece q1 to qn are alternately aligned in the vertical direction by aligning the reference marks m in the vertical direction. It is characterized by

In this embodiment, the reference mark m for lamination alignment is the third
As shown in FIG. 3A and FIG. 3A, one end of the upper horizontal line
, and by extending a lower horizontal line 2 from the lower end of the vertical line y in a direction opposite to the upper horizontal line X.

Further, the reference marks m for lamination alignment provided on the opposite sides of the 1806 are each horizontally located above one mark m.
'A x is formed to extend in the opposite direction to the upper horizontal line y of the other mark M.

The vertical line y is used for positioning the piezoelectric element pieces q1 to qn around the axis of rotation, and can prevent misalignment around the coaxial line.

On the other hand, the upper horizontal line X and the lower horizontal line 2 are used for alignment in the electrode extending direction, and can indicate the extending direction (front and back) of the electrode.

With this configuration, it is possible to form a piezoelectric element using the piezoelectric element pieces q1 to qn having the same structure and the same reference mark m for lamination alignment, and the piezoelectric element piece q
When laminating 1 = q n, each piezoelectric element piece qt-
By aligning the reference marks m for lamination positioning provided on the piezoelectric element pieces qn, the piezoelectric element pieces q1 to qn are alternately stacked upside down and stacked, and the insulating side side portion S1 provided on the side surface of each piezoelectric element piece q1 to qn and the electrode side are automatically and accurately aligned. Side S! and can be arranged alternately in the vertical direction.

Therefore, the work of laminating all the piezoelectric element pieces qt"-qn can be performed extremely easily.

Furthermore, by aligning the reference marks m for lamination alignment, the insulating side portions and electrode side portions provided on the side surfaces of each piezoelectric element piece q1 to qn are alternately aligned in the vertical direction. , the insulating side portions S, and the electrode side portions S2 can be accurately aligned alternately in the vertical direction.

Therefore, the work of applying the conductive adhesive material PB can be easily performed, and the electrode formation can be performed easily and accurately.

Note that the reference mark m for lamination positioning is used for the above-mentioned positioning, that is, for the insulating side side S of all the piezoelectric element pieces 91 to qn.
Any figure, symbol, or character can be used as long as it allows easy and accurate alignment of the electrode side part S2 and the electrode side part S2.

Further, in this embodiment, the material of each piezoelectric element piece 91 to qn is, for example, a ferroelectric material having an ABO3 perovskite crystal structure, such as PZT (Pb(Zr4i)
Oa) system, PLZT (Pb, La(Zr, Ti)
Os) system, FT (PbTiOz) system, or PZT
A three-component piezoelectric ceramic based on the above can be used.

Although it is possible to use a glass epoxy substrate etc. for the substrate r, in this example, a ceramic substrate with excellent heat resistance and mechanical strength is used, and a silver paste is used for the conductive adhesive p. , the laminated piezoelectric element pieces qt""'qn and the substrate r are baked and bonded at approximately 800°C while applying a voltage to form an integrated piezoelectric element Q, and the adhesive strength between the piezoelectric element pieces q1 to qn and the substrate r is determined. At the same time, the silver particles in the silver paste are welded together to increase conductivity.

Next, a piezoelectric actuator A using a piezoelectric element having the above configuration will be explained.

As shown in Fig. 4, a plunger P is disposed concentrically in a cylindrical case having front and rear walls a and b, and is movable back and forth along the axis. Clamp member k.

a pair of clamping piezoelectric elements e and f equipped with
It is constructed by arranging a stroke piezoelectric element g.

That is, the piezoelectric element e for clamping is arranged and supported below the holding tool attached to the center of the case, while the piezoelectric element f for clamping and the piezoelectric element g for stroke are placed below the holding tool. It is placed and held on the upper side.

Next, the action of each piezoelectric element e, f, and H will be explained.

When a voltage is applied to the piezoelectric elements e and f, the clamp member
1, the plunger P is turned on, and when no voltage is applied, the clamp is released.

On the other hand, the piezoelectric element g is configured to shorten in the axial direction when a voltage is applied, and to expand and return to its original position when the voltage is removed.

FIG. 5 shows the configuration of a control device C for controlling the piezoelectric actuator A having the above configuration. Interface■
, an output interface I connected to piezoelectric elements e, f, and g via a drive circuit, and piezoelectric element e+ f+
It is composed of a memory M that stores a drive program for H.

Next, the movement of the plunger P by the actuator A having such a configuration will be explained with reference to FIGS. 6 to 9.

When a drive signal is input according to the control device C, according to the program, as shown in FIG. 6, a voltage is applied to the piezoelectric element f to clamp the plunger P, and then the voltage to the piezoelectric element e is stopped to clamp the plunger P. Release the P clamp.

Next, as shown in FIG. 7, when a voltage is applied to the piezoelectric element g to make it contract, the piezoelectric element g moves in the direction of the arrow, and the plunger P clamped by the piezoelectric element f also moves in the direction of the arrow. do.

Thereafter, as shown in FIG. 8, a voltage is applied to the piezoelectric element e to clamp the plunger P, and then the voltage applied to the piezoelectric element r is released to release the clamp on the plunger P.

Then, as shown in FIG. 9, the voltage applied to the piezoelectric element g is released and expanded, and only the piezoelectric element f is moved in the direction of the arrow, returning to the state shown in FIG. 6.

After that, by repeating the above operation, plunger P
can be moved in a linear manner with a stroke on the μm order or sub-μm order, and various devices and machines can be operated precisely.

Fig. 1O shows an automatic valve V in which a piezoelectric actuator A of the present invention is used to drive a diaphragm-type valve body. An inflow path 11 and an outflow path 12 are provided which are connected to each other. In addition, in the valve box 10, an inflow path 11 and an outflow path 1 are provided.
2, a main valve hole 13 is formed, and a main valve seat 14 is formed around the upper opening of the main valve hole 13.

A diaphragm 15, which also serves as a main valve body for opening and closing the main valve hole 13, is disposed on the main valve seat 14 so as to be able to move toward and away from the main valve seat 14.

A diaphragm back chamber 16 is formed above the diaphragm 15, and the diaphragm back chamber 16 is connected to the inflow path 1 through an orifice 17 provided at the periphery of the diaphragm 15.
It communicates with 1.

A pilot valve hole 18 is formed in the diaphragm 15, and allows the diaphragm back chamber 16 and the outflow path 12 to communicate with each other.

A pilot valve body 19 provided at the lower end of a plunger P of a piezoelectric actuator A is opposed above the pilot valve hole 18, and the pilot valve hole 18 is opened and closed by the operation of the piezoelectric actuator A.

With the above configuration, the automatic valve (■) uses the self-servo action of the diaphragm-type valve body, and the diaphragm (5) follows the movement of the plunger P of the piezoelectric actuator A, and the main valve seat 1
4 to open and close.

20 is a flange that limits the vertical stroke of the plunger P, and 21 is a seal having a Y-shaped cross section.

[Brief Description of the Drawings] Fig. 1 is a cross-sectional side view of an embodiment of a piezoelectric element according to the present invention;
2 is a plan view of the same, FIG. 3 is an exploded perspective view, FIG. 3A is an enlarged explanatory view of a fiducial mark for lamination alignment, FIG. 4 is a cross-sectional explanatory view of a piezoelectric actuator equipped with the piezoelectric element, and FIG. The figure is a block diagram showing the configuration of the control device, Figures 6 to 9.
FIG. 10 is a cross-sectional view of a single-valve type automatic valve constructed using the piezoelectric actuator, and FIG. 11 is a cross-sectional side view of a conventional piezoelectric element. In the figure, (m): Reference mark for lamination alignment <pr>: Insulating adhesive (A t): Insulating part (Q): Piezoelectric element (p): Conductive adhesive <pa>: Extending part ( pb): Conductive adhesive for drawer (ql) ~ (11111): Piezoelectric element piece Fig. Fig. Fig. 3A Fig. 4 Fig. 10 Fig. 11

Claims (1)

[Claims] 1. In a piezoelectric element (Q) in which a plurality of piezoelectric element pieces (q1) to (qn) are laminated with a conductive adhesive (p) interposed between them, on the side surface of each piezoelectric element piece (q1) to (qn), The insulation side provided on the side surface of each piezoelectric element piece (q1) to (qn) is provided with a reference mark (m) for lamination alignment, and by vertically aligning the reference mark (m) for lamination alignment. 1. A piezoelectric element that can be easily stacked, characterized in that portions and electrode side portions are alternately aligned in the vertical direction.