JP2913675B2 - Easy-to-stack piezoelectric elements - Google Patents

Description

The present invention relates to a piezoelectric element that can be used for a laminated piezoelectric actuator or the like and that can be easily manufactured.

(B) Conventional technology Conventionally, as one form of a piezoelectric actuator, there is a laminated type constituted 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 lamination and bonding of the plurality of piezoelectric element pieces
Laminated and bonded so that the insulating side portions 51a and the electrode side portions 51b provided on the sides facing each other by about 180 degrees alternately appear in a vertically aligned state, and are laminated and bonded to the substrate 54. After that, the conductive adhesives 52 and 53 are applied along the 180 ° facing side surfaces of the stacked piezoelectric element piece combination by the conductive adhesives 52 and 53, and the piezoelectric element pieces are applied to the substrate 54. Will be connected.

(C) Problems to be solved by the invention However, the above-mentioned piezoelectric element still has the following problems.

As described above, when laminating the plurality of piezoelectric element pieces 51, the insulating side parts 51a and the electrode side parts 51b provided on the sides of each piezoelectric element piece 51 facing each other by about 180 degrees alternately in the vertical direction. Although it is necessary to make it appear in an aligned state, if this is done manually, alignment is difficult.

In addition, since alignment is difficult, each piezoelectric element piece
The insulating side portions 51a and the electrode side portions 51b provided on the side opposite to each other by about 180 degrees cannot alternately appear in a vertically aligned state, and thereafter, the conductive adhesives 52, 53 This makes it difficult to perform a coating operation, and a reliable connection between the substrate 54 and the electrode of each piezoelectric element piece 51 cannot be secured.

SUMMARY OF THE INVENTION An object of the present invention is to provide an easily stackable piezoelectric element that can solve the above problems.

(D) Means for Solving the Problems The present invention relates to a piezoelectric element laminated with a conductive adhesive interposed between a plurality of piezoelectric element pieces, and the front and back of each piezoelectric element piece are provided on the side face of each piezoelectric element piece. Are provided, and a reference mark for stacking alignment for indicating the position of each piezoelectric element piece around the rotation axis is provided, and each of the piezoelectric element pieces is aligned by vertical alignment of the stacking alignment reference mark. The present invention relates to an easy-to-stack piezoelectric element characterized in that the insulating side portions and the electrode side portions provided on the side surfaces are alternately arranged in the vertical direction.

(E) Function / Effect According to the present invention, when the piezoelectric element pieces are laminated, the respective piezoelectric element pieces are automatically arranged 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 can be arranged alternately in the vertical direction.

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

Also, since the insulating side portions and the electrode side portions provided on the side surfaces of the respective piezoelectric element pieces are arranged alternately in the vertical direction by aligning the reference marks for stacking alignment, the insulating side The part and the electrode side part can be alternately and accurately aligned in the vertical direction.

Therefore, the operation of applying the conductive adhesive can be easily performed, and the connection between the substrate and the electrodes of the respective piezoelectric element pieces can be easily and reliably performed.

(F) Embodiment FIGS. 1 to 3 show one embodiment of the present invention, in which thick electric element pieces q1 to qn on substantially rings each having a predetermined thickness.
And the substrate r are laminated and bonded to form an integrated piezoelectric element Q.

In the piezoelectric element Q thus integrally laminated and bonded, the conductive adhesive p interposed between the piezoelectric element pieces q1 to qn can be used as an electrode.

That is, as shown in FIG. 2, a conductive adhesive p such as a silver paste is applied to both surfaces of each of the piezoelectric element pieces q1 to qn by using a method such as screen printing to form a conductive adhesive p. The pattern is formed.

This pattern is composed of an insulating portion At in which an insulating adhesive pr of a predetermined width is applied from the outer peripheral edge of each of the piezoelectric element pieces q1 to qn, an adhesive portion pc in which a conductive adhesive p is applied, and an adhesive portion pc having the same. And an extended portion pa coated with a conductive adhesive p that reaches the outer peripheral edge of each of the piezoelectric element pieces q1 to qn.

The extending portions pa are applied to both surfaces of each of the piezoelectric element pieces q1 to qn, but the positions of the front and rear surfaces are different from each other, for example, by 180 °.

Then, the piezoelectric element pieces q1 to qn are laminated with the extension parts pa facing each other and the insulating parts At facing each other, and these piezoelectric element pieces q1 to qn are laminated on the substrate r coated with the conductive adhesive p, The integrated piezoelectric element Q is formed by pressure bonding.

The bonding portion pc and the extension portion pa can be formed on the piezoelectric element pieces q1 to qn at the same time as the conductive bonding material p of the bonding portion pc by a method such as screen printing, and the insulating portion At can be similarly formed. Can be formed by a method such as screen printing.

A conductive adhesive pb for drawing is applied to the outer surface of the piezoelectric element Q laminated in this manner outside the extending portion pa, and each conductive adhesive p is connected to a terminal w provided on the substrate r. Let me.

Further, the electrodes between the piezoelectric element pieces q1 to qn are stacked with the extending portions pa of the conductive adhesive p facing each other, so that every other electrode is connected in parallel to one terminal w. The remaining electrodes are connected to the other terminal w, so that a voltage can be applied to each of the piezoelectric element pieces q1 to qn.

According to the present invention, in the above-described configuration, further, FIGS.
As shown in the figure, the front and back of each piezoelectric element piece q1 to qn are displayed on the side surface of each piezoelectric element piece q1 to qn, and each piezoelectric element piece q1 to
A reference mark m for stacking positioning for indicating the position of the rotation axis of qn around the rotation axis is provided, and each of the piezoelectric element pieces q1
An insulating side side S ₁ and the electrode-side side S ₂ provided on the side surface of the ~qn is,
It is characterized by having a configuration in which it is arranged alternately in the vertical direction.

In this embodiment, as shown in FIGS. 3 and 3A, one end of the upper horizontal line x is formed by bending one end of the upper horizontal line x downward on the side facing 180 °, as shown in FIGS. 3 and 3A. The lower horizontal line z is formed to extend from the lower end of the vertical line y in a direction opposite to the upper horizontal line x.

Also, the reference marks m for stacking alignment provided on the side facing 180 ° are formed such that the upper horizontal line x of one mark m extends in the opposite direction to the upper horizontal line y of the other mark M. ing.

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

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

With such a configuration, a piezoelectric element can be formed using the piezoelectric element pieces q1 to qn having the same structure and the same stacking alignment reference mark m, and the piezoelectric element pieces q1 to
When stacking qn, they are stacked upside down alternately simply by simply aligning the stacking alignment reference marks m provided on each of the piezoelectric element pieces q1 to qn, automatically, and accurately, for each of the piezoelectric element pieces q1 to qn. provided on the side surface insulating side side S ₁ and the electrode-side side portion S ₂
And can be alternately arranged in the vertical direction.

Therefore, the lamination work of all the piezoelectric element pieces q1 to qn can be performed extremely easily.

Also, by aligning the stacking alignment reference marks m, the insulating side portions and the electrode side portions provided on the side surfaces of the respective piezoelectric element pieces q1 to qn are alternately aligned in the vertical direction. and an insulating-side side S ₁ and the electrode-side side S _2, can be accurately aligned alternately in the vertical direction.

Therefore, the operation of applying the conductive adhesive material pb can be easily performed, and the electrodes can be easily and accurately formed.

Incidentally, the reference mark m laminated alignment, alignment described above, i.e., it is possible to perform all the piezoelectric element piece q1~qn insulating side alignment of the immediate portion S ₁ and the electrode-side side S ₂ easily and accurately Any form, symbol, or character can be used in the form.

In the present embodiment, the material of each of the piezoelectric element pieces q1 to qn is, for example, a ferroelectric material having an ABO ₃ perovskite type crystal structure, such as PZT [Pb (Zr, Ti) O ₃ ], PLZT
[Pb, La (Zr, Ti) O ₃ ], Pt [PbTiO ₃ ], or PZ
T-based ternary piezoelectric ceramics or the like can be used.

Although a glass epoxy substrate or the like may be used as the substrate r, in this embodiment, a ceramic substrate having excellent heat resistance and mechanical strength is used, and a silver paste is used as the conductive adhesive p. The laminated piezoelectric element pieces q1 to qn and the substrate r
By applying and baking at about 800 ° C. to form an integrated piezoelectric element Q, determine the adhesive strength between the piezoelectric element pieces q1 to qn and the substrate r, and weld the silver fine particles in the silver paste to each other. To increase conductivity.

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

As shown in FIG. 4, a plunger P is disposed concentrically in a cylindrical case having front and rear walls a and b so as to be able to advance and retreat along an axis. It is configured by disposing a pair of clamping piezoelectric elements e and f having the clamping members k and l and a stroke piezoelectric element g.

That is, the clamping piezoelectric element e is disposed and supported below the holder h attached to the center of the case, while the clamping piezoelectric element f and the stroke piezoelectric element g are connected to the holder h. Arranged and held on the upper side.

 Next, the operation of each of the piezoelectric elements e, f, and g will be described.

The piezoelectric elements e and f clamp the plunger P via the clamp members k and l when a voltage is applied, and release the clamp when no voltage is applied.

On the other hand, when a voltage is applied, the piezoelectric element g contracts in the axial direction, and when the voltage is released, the piezoelectric element g expands and returns.

FIG. 5 shows a configuration of a control device C for controlling the piezoelectric actuator A having the above configuration. The control device C includes a microprocessor MPU and an input connected to a switch SW for outputting a drive signal. Interface I
And an output interface I connected to the piezoelectric elements e, f, g via a drive circuit D, and a memory M for storing a drive program for the piezoelectric elements e, f, g.

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

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

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

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

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

Thereafter, by repeating the above operation, the plunger P can be moved like a scale with a stroke of the order of μm or sub-μm, and various devices and machines can be operated accurately.

FIG. 10 shows an automatic valve V configured to drive a diaphragm type valve element by the piezoelectric actuator A of the present invention,
Reference numeral 10 denotes a valve box, which is provided with an inflow path 11 and an outflow path 12 which are respectively connected to a primary pipe and a secondary pipe. In the valve box 10, a main valve hole 13 is formed between the inflow path 11 and the outflow path 12, and a main valve seat 14 is formed around the upper end opening of the main valve hole 13.

Further, on the main valve seat 14, a diaphragm 15 also serving as a main valve body for opening and closing the main valve hole 13 is disposed so as to be able to freely contact and separate.

Above the diaphragm 15, a diaphragm back chamber 16 is formed, and the diaphragm back chamber 16 is
Communicates with the inflow passage 11 through an orifice 17 provided on the periphery of the inflow passage.

Reference numeral 18 denotes a pilot valve hole formed in the diaphragm 15 and connects the diaphragm back chamber 16 to the outflow passage 12.

A pilot valve element 19 provided at the lower end of the plunger P of the piezoelectric actuator A faces 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-described configuration, the automatic valve V is a self-servo action of the diaphragm type valve pair, and the diaphragm 15 follows the movement of the plunger P of the piezoelectric actuator A to cause the main valve seat 14 to move.
To open and close.

Reference numeral 20 denotes a flange for limiting the vertical stroke of the plunger P, and reference numeral 21 denotes a Y-shaped seal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a 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 reference mark for stacking alignment, FIG. 4 is an explanatory sectional view of a piezoelectric actuator having a piezoelectric element, and FIG. 6 is a block diagram showing the configuration of the control device, FIGS. 6 to 9 are explanatory diagrams of the operation of the actuator, FIG. 10 is a sectional view of a single-valve type automatic valve constituted by the piezoelectric actuator, FIG.
The figure is a sectional side view of a conventional piezoelectric element. In the figure, (m): reference mark for stacking alignment (pr): insulating adhesive (At): insulating part (Q): piezoelectric element (p): conductive adhesive (pa): extension part (pb) ): Lead-out conductive adhesive (q1) to (qn): Piezoelectric element piece

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masakatsu Kiyohara 2-8-1, Honmura, Chigasaki-shi, Kanagawa Prefecture Tochiki Kikai Co., Ltd. Chigasaki Plant (56) References Real Opening Sho 62-28460 (JP, U) 58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 41/00-41/26

Claims (1)

(57) [Claims] 1. A piezoelectric element (Q) laminated by interposing a conductive adhesive (p) between a plurality of piezoelectric element pieces (q1) to (qn).
, The front and back of each of the piezoelectric element pieces (q1) to (qn) are displayed on the side surfaces of each of the piezoelectric element pieces (q1) to (qn), and the rotation axis of each of the piezoelectric element pieces (q1) to (qn). Each of the piezoelectric element pieces (q1) to (qn) is provided with a stacking alignment reference mark (m) for displaying the surrounding position and by vertically aligning the stacking alignment reference mark (m). An easy-to-stack piezoelectric element characterized in that the insulating side portions and the electrode side portions provided on the side surfaces are alternately arranged in the vertical direction.