JP2002261343A - Laminated one-body baked type electromechanical conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated one-body baking type electromechanical conversion element, having the same or more electrode characteristics than that of Ag-Pd-based electrode, especially having a low rigidity of the inner electrode layer and small inner stress generated at expansion or shrinkage of a ceramic layer, while using a low-cost electrode material. SOLUTION: The laminated one-body baking type electromechanical conversion element includes a laminate, in which a plurality of ceramic layers 11 made of piezoelectric ceramics or of electrostriction ceramics, and inner electrode layers 21 and 22 between the ceramic layers 11 are baked. The inner electrode layers 21 and 22 contain base metal with modulus of rigidity of 160 GPa or lower as a main component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated integrated firing type electromechanical transducer using a piezoelectric or electrostrictive material.

[0002]

2. Description of the Related Art A laminated monolithic electromechanical transducer used in actuators, piezoelectric transformers, ultrasonic motors, and the like is composed of a plurality of ceramic layers made of piezoelectric ceramics or electrostrictive ceramics, and an internal layer interposed between the ceramic layers. It is manufactured by integrally firing the electrode layer.

[0003] In the electro-mechanical transducer of the laminated integral firing type, a stress is generated between the internal electrode and the ceramic layer because an inverse piezoelectric effect that distortion is generated by applying a voltage is obtained. Furthermore, there is a basic property that heat is generated by repeated application of a voltage. Therefore, the characteristics required for the internal electrode layer are: 1. low electrical resistance and low loss of injected charge; 2. High thermal conductivity and excellent heat dissipation. 3. Excellent migration resistance; 4. Low rigidity, small internal stress and no cracks. 5. High bonding strength with ceramics and no peeling during use. And low cost.

[0004] In the conventional laminated integral firing type electromechanical transducer, an Ag-Pd-based metal material is widely used as an electrode material. Ag has high conductivity and is relatively inexpensive, but has a low melting point of 960 ° C. and easily causes migration, so that Ag alone is inferior in reliability. On the other hand, Pd is expensive but has a high melting point, and therefore, by using an Ag-Pd-based metal material, it is possible to suppress migration and increase the melting point of the electrode material (described in JP-A-5-304443). Therefore, as described above, Ag-Pd-based metal materials are widely used.

However, although the migration is suppressed by the addition of Pd, the bonding between the electrode material and the ceramic material is not sufficient, and as a countermeasure for this, as disclosed in JP-A-5-304443, JP-A-8-255509 and others. Various measures have been taken. In addition, although migration is suppressed by adding Pd, it is industrially problematic because the cost is increased. Therefore, there is a need for a laminated and integrally fired electromechanical transducer using a low-cost electrode material having electrode characteristics equal to or higher than that of an Ag-Pd-based metal material.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has an electrode characteristic that is equal to or higher than that of an Ag-Pd-based electrode and uses a low-cost electrode material to integrally laminate and fire. It is an object of the present invention to provide an electromechanical transducer of the type, in particular, one in which the rigidity of the internal electrode layer is low and the internal stress generated when the ceramic layer expands and contracts is small.

[0007]

According to the first aspect of the present invention, a plurality of ceramic layers made of piezoelectric ceramics or electrostrictive ceramics and an internal electrode layer interposed between the ceramic layers are integrally fired. In the laminated monolithic electromechanical transducer having the laminated body, the internal electrode layer is mainly composed of a base metal having a rigidity of 160 GPa or less.

A point to be noted in the present invention is that a base metal having a specific property of a rigidity of 160 GPa or less is applied as a main component of the internal electrode layer. This makes it possible to reduce the rigidity of the entire internal electrode layer in the laminated integral firing type electromechanical transducer.
Therefore, when the electromechanical transducer is driven, the internal stress caused by the expansion and contraction of the ceramic layer can be reduced. Further, since the main component of the internal electrode layer is a base metal, compared with the case of using a conventional Ag-Pd-based material,
Cost reduction can be achieved.

When the Vickers height Hv exceeds 50, or when the rigidity (Young's modulus) exceeds 160 GPa, the rigidity of the entire internal electrode layer increases, and the internal stress during expansion and contraction increases. Therefore, cracks and the like may be induced.

That is, for example, in the case of a laminated actuator, if the longitudinal distortion in the laminating direction is X, there is a property that about 1 / 3X distortion occurs in the lateral direction at the same time. Therefore, a shear stress is generated between the internal electrode layer and the ceramic layer. Therefore, the electrode material needs to be a material with low rigidity. The rigidity of a pure metal of 30% Ag-Pd conventionally used as an electrode material is unknown, but the 500 ° C. annealed Ag is replaced with Ag.
Multiplying the rigidity of pure metal Ag, 100.5 GPa (see Table 3), by 1.6 times, the rate of increase in hardness to 30% Pd, results in about 160 GPa. Therefore, in order not to impair the displacement performance and reliability of the actuator, the rigidity of the pure metal needs to be 160 GPa or less, and the internal stress is estimated to be equal to or less than 30% of AgPd.

If the rigidity of the pure metal is 160 GPa or less, the internal stress is estimated to be equal to or less than 30% of Ag-Pd. The corresponding base metal is Al, Cu, or the like. In particular, Cu described below has a small volume resistivity of 15 μΩcm and a melting point of 10 μΩcm.
83 ° C and 900-105 which is the sintering temperature of ceramics
This is more preferable because it is larger and close to 0 ° C. (see Embodiment 9 described later).

Next, as in the second aspect of the present invention, the displacement of the electromechanical transducer during driving can be set to 0.06 to 0.15%. That is, the larger the displacement is, the larger the internal stress in the electromechanical transducer becomes, and the more likely it is to induce cracks. On the other hand, even when the displacement is as high as 0.06% or more as described above, the use of the specific base metal can suppress the internal stress and prevent the occurrence of cracks. A displacement of 0.15% or more is not preferable because the strength of the ceramic layer itself is reduced due to repeated fatigue and the life is shortened irrespective of the electrode.

It is preferable that the average thickness of the electrode layer is 1 to 8 μm. When the average film thickness is more than 8 μm, there is a problem that the rigidity of the internal electrode layer is increased and the internal stress during driving is increased. If the thickness is less than 1 μm, the resistance value of the electrode is high, and the manufacturing variation is undesirably large.

According to a fourth aspect of the present invention, an electrode formation ratio, which is a ratio of an electrode formation portion to the entire length of the internal electrode exposed on a cut surface in the stacking direction of the stack, is 75% or more. it can. If the electrode formation rate becomes higher,
The rigidity of the entire internal electrode layer tends to increase. However, in the present invention, since the rigidity of the internal electrode layer itself can be reduced as described above, the effect of increasing the rigidity due to the improvement in the electrode formation rate can be reduced, and conversely, the effect of reducing the electrical resistance can be obtained. .

Preferably, the main component of the electrode layer is Cu, a Cu alloy or an oxide thereof. Cu, Cu alloys or their oxides are relatively inexpensive and have a rigidity of 160 GPa.
The following requirements for base metals can be reliably satisfied (see Table 3).

Further, it is preferable that the electrode layer further contains at least one of Ca, Mg and Sr. That is, since the electromechanical transducer of the present invention is of a laminated integral sintering type, a green sheet for forming a ceramic layer and a laminate in which an electrode paste material for forming the electrode layer is alternately arranged. Form
This is manufactured by integrally firing. At this time, it is preferable that the electrode paste material contains Cu and the like as a main component of the electrode layer, and also contains a component having at least one of Ca, Mg, and Sr. In this case, as described above, the electrode layer obtained after the integral firing has C
At least one of a, Mg, and Sr is contained.

[0017] Then, Ca,
By including a component having at least one of Mg and Sr, the following excellent operational effects can be obtained during integral firing. That is, if a component having at least one of Ca, Mg, and Sr, such as CaO, MgO, and SrO, is present in the electrode paste material, the laminate of the green sheet and the electrode paste material is integrated. During firing, the effect of preventing or suppressing the melting of the mixture of Cu and the ceramic material or the effect of increasing the melting point of the mixture is obtained. Thereby, it is possible to prevent the melt containing Cu from flowing into the ceramic layer and causing segregation. Thus, the obtained ceramic layer is fired in a state where the original excellent performance can be sufficiently exhibited.

Next, the ceramic layer is preferably made of PZT, which is a Pb (Zr, Ti) O ₃ -based oxide having a perovskite structure. This PZT exhibits very excellent characteristics as a ceramic layer for an electromechanical transducer.

Further, according to the present invention, the PZ
T preferably contains at least one of Mo and W. As a result, the effect of lowering the sintering temperature of PZT and facilitating simultaneous firing with Cu can be obtained.

Further, as in the ninth aspect of the present invention, the electromechanical transducer can be used in any of an actuator, a piezoelectric transformer, and an ultrasonic motor. In addition, the cost of these products can be reduced and the performance can be improved.

Further, as in the tenth aspect of the present invention, the electromechanical transducer can be used for a fuel injection actuator in an injector. That is, the fuel injection actuator is required to have low cost, high speed response, high durability, and reliability. These can be satisfied by employing the electromechanical transducer.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A laminated integrated firing type electromechanical transducer according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 1, a ceramic layer 1 made of PZT is used.
1, an internal electrode layer 21 interposed between the ceramic layers,
Thus, an electromechanical conversion element of a laminated integral sintering type having the laminated body 10 obtained by integrally sintering 22 and 22 was produced.

First, in order to obtain a green sheet for producing a ceramic layer, the chemical composition is (Pb _0.92 S
r _0.09 ) {(Zr _0.54 Ti _0.46 ) _0.985 (Y _0.5 Nb _0.5 )
_0.01 Mn _{0. 005}} O ₃ +0.5 outer mol% Pb _0.83 W _0.17
The PZT raw material powder was adjusted to O _X was prepared.
Next, polyvinyl alcohol and BB were added to the PZT raw material powder.
After adding P, an organic solvent, and a dispersant, and kneading the mixture for 48 H using a ball mill, a green sheet having a thickness of 110 μm was prepared by a doctor blade method.

The electrode paste material is an organic vehicle obtained by dissolving ethyl cellulose with terpineol and a resin agent (acrylic resin, arachid resin, ethocell resin, etc.).
35 wt% and CuO powder (average particle size: 0.2 to 0.5 μm)
It was produced by kneading 65 wt%.

The collected green sheet is punched by a press or cut by a cutter to form a rectangular body having a predetermined size. Next, as shown in FIG. 2, the electrode paste material was applied to one surface of the formed green sheet 11 by screen printing. In this example, the print thickness was 15 μm. Next, as shown in FIG.
About 00 green sheets 11 are stacked. At this time, the electrode paste materials 21 and 22 alternately reach the left and right side surfaces 101 and 102 (FIGS. 1 and 2).
Next, the laminate was pressed and cut to a predetermined size.

Next, after the laminate was degreased in an air atmosphere, a metallizing step was performed. The metallizing step is performed in a reducing atmosphere at a relatively low temperature, in which Cu
This is a step of reducing O to Cu. In this example, since the ceramic material is an oxide containing at least lead on the chemical formula,
Eutectic point of lead and copper: The atmosphere was adjusted just below 326 ° C. for reduction.

The metallizing step is a step of reducing CuO in the electrode paste material to Cu in a relatively low-temperature reducing atmosphere. In this example, since the ceramic material is an oxide containing at least lead on the chemical formula, the eutectic point of lead and copper: 3
The atmosphere was adjusted just below 26 ° C. to reduce.

Next, a firing step for integrally firing the laminate was performed. In this example, the temperature is 965 ° C. and the oxygen partial pressure is 1
The baking was performed while adjusting to 0 ^-6 atm. Next, the obtained sintered body was ground and processed into 7 × 7 × 20 mm, 5 × 5 × 20 mm, and 4.2 × 4.2 × 30 mm, respectively.
After printing and printing the side electrodes 31, 32 as shown in FIG.
A lead wire (not shown) was attached. Thereafter, a polarization treatment was performed by applying a voltage of 150 V for 30 minutes in silicon oil at 130 ° C., thereby producing a laminated integrated firing type electromechanical transducer 1. This is designated as Product E1 of the present invention.

Next, various performances and the like of the electromechanical transducer 1 of the present example (product E1 of the present invention) were measured. The product E1 of the present invention had a ceramic layer thickness of 90 μm, an electrode film thickness of 4.5 μm, and an electrode formation ratio of 98%. Load load 10MPa, applied voltage 15
The static displacement at 0 V was 1 μm / mm, showing good characteristics as an actuator.

Next, in this example, the same PZT composition and 30% Ag-Pd electrode paste as that of the product E1 of the present invention were used as comparative products so as to have the same physique, the same layer thickness, and the same film thickness. The produced laminated integrated firing type electromechanical transducer was produced (referred to as comparative product C1). Then, the product E of the present invention
1 and the resistance value of the electrode of the comparative product C1 were compared. In the comparative product C1, the electrode formation rate was 97%. As a result of the comparison, the resistance value per electrode layer is the Ag- of the comparative product C1.
Pd 30% is 0.15Ω, and the Cu electrode of the product E1 of the present invention is 0.15Ω.
It was 06Ω.

Next, in the present embodiment, in the first embodiment,
Stress when a DC voltage of 150 V is applied using a model of a laminated and integrated sintering-type electromechanical transducer element of the present invention product E1 (Cu electrode) and comparative product C1 (Ag-Pd 30% electrode) having a body size of 7 × 7 × 20 mm. Calculations were made. The measured displacement in the vertical direction at this time is 0.08%. The rigidity used in the calculation was 70 GPa for ceramics and 30% for Ag-Pd electrodes.
60 GPa, the Cu electrode was 136 GPa, and the Poisson ratio was 0.3.

As a result, the comparative product C1 (Ag-Pd 30%
(Electrode) internal stress of 37MPa (tensile stress)
However, it was found that in the case of the product E1 (Cu electrode) of the present invention, an internal stress of 31 MPa was generated in each of the ceramic layers. The internal stress exceeds 40 MPa when the thickness of the Cu electrode is 8 μm or more.

Embodiment 2 In this embodiment, comparative measurement of heat dissipation was performed using the product E1 of the present invention and the comparative product C1 in Embodiment 1. The measurement was performed by applying a load of 20 MPa and an applied voltage of 0 to each electromechanical transducer.
A positive voltage trapezoidal wave with a voltage of 150 V
The device was driven by changing the injection energy at 00 Hz, and the device surface temperature after 10 minutes was measured with a radiation thermometer. The displacement at this time was 0.06%.

Table 1 shows the results. The exothermic temperature is
All of the E1 Cu electrode products are smaller and have a volume of 500 mm.
^ThreeIn the case above, the cross-sectional area is 18mm^TwoIn the above case, the injection energy
Gee 0.021mJ / mm^ThreeIn the case of
Was. This is because the heat conductivity of the Cu electrode is high and the heat dissipation is good.
It is thought to be a disaster.

[0035]

[Table 1]

Embodiment 3 In this embodiment, the physique of the embodiment 1 is 7 × 7 × 20 m.
m of the present invention E1 (Cu electrode) and comparative product C1 (Ag-P
The migration resistance was compared using an electromechanical transducer of a laminated integral firing type (d30% electrode).

As shown in FIG. 1, each of the electromechanical transducers has a structure in which a positive electrode and a negative electrode are alternately exposed on the side surfaces not connected to the side electrodes 31, 32, and the surface is made of a resin for securing insulation. Some silicon grease was not applied. These electromechanical transducers were subjected to 90 V in an atmosphere at room temperature and a relative humidity of 40 to 50%.
Of DC voltage (electric field intensity of 1 kV / mm) was applied, and the time until short-circuit was evaluated for each three.

As a result, the comparative product C1 (Ag-Pd 30%
The electrode product was short-circuited in 25, 37, 68 hours. On the other hand, the product E1 (Cu electrode product) of the present invention did not short-circuit even after 100 hours, and exhibited excellent migration resistance.

Fourth Embodiment In this embodiment, a physique of 7 × 7 × 20 m in the first embodiment is used.
m of the present invention E1 (Cu electrode) and comparative product C1 (Ag-P
(30% electrode), the bonding strength was measured using an electromechanical transducer of a laminated integral firing type. The electrode formation rate of both is 98%
Met. For comparison, Ag-P was used as a comparative product C2.
An electromechanical conversion element of a laminated integral firing type having an electrode formation rate of 75% with d30% electrodes was also prepared, and the bonding strength was measured.

As a result, the joint strength of the product E1 of the present invention (Cu electrode, electrode formation rate 98%) was 35 to 50 MPa, and that of the comparative product C1 (Ag-Pd 30% electrode, electrode formation rate 98%) was 15 to 50 MPa. 30 MPa, comparative product C2 (Ag-Pd3
(0% electrode, electrode formation rate 85%), the bonding strength is 25-40.
MPa. Therefore, in the case of the product E1 (Cu electrode) of the present invention, the bonding strength is 40 MPa and the electrode formation rate is 75% or more.
It was confirmed that there was.

Embodiment 5 In this embodiment, first, as shown in Table 2, nine types of samples (samples 1 to 9) were prepared as electrode paste materials. Then, an electromechanical conversion element was manufactured using this.

[0042]

[Table 2]

The electrode paste material was prepared as follows. An organic vehicle obtained by dissolving ethyl cellulose with terpineol and a resin agent (acrylic resin, arachid resin, ethocell resin, etc.) are mixed with CuO powder (average particle size:
0.2-0.5 μm) and additives (CaO, MgO, Sr
O) was kneaded at a mixing ratio as shown in Table 2 to prepare an electrode paste material.
However, CaCO ₃ is used as a material for obtaining CaO,
As a material for obtaining SrO, SrCO ₃ was used in terms of the molecular weight ratio in the chemical formula. (Hereinafter, CaO, S
Same for rO)

Using these CuO paste materials, a laminate was prepared in the following procedure. However, in this example, the number of layers was three for the test. First, a green sheet formed by molding a ceramic material into a sheet shape was manufactured by using the same doctor blade method as in the first embodiment.

Next, the paste material for each electrode was applied to the surface of the green sheet by screen printing as in the first embodiment. The thickness at the time of printing was 15 μm. next,
As shown in FIG. 3, two green sheet sheets 11 on which the electrode paste material 2 was printed and one unprinted green sheet 11 were laminated and pressed together, and cut to a predetermined size.

Next, after degreased in the air,
A metallization step was performed. As in the case of the first embodiment, the conditions were such that the atmosphere was adjusted and reduced immediately below 326 ° C. Next, a firing step was performed. The firing temperature varies depending on the density change of the element material. In this example, the temperature is 950 ° C. The adjustment atmosphere is adjusted to an atmosphere in which Cu is not oxidized as much as possible and oxides in the element portion are not reduced as much as possible. In this example, the oxygen partial pressure was adjusted at 950 ° C. to about 10 ⁻⁴ atm.

Next, as shown in FIG. 4, the cross-section of the obtained electro-mechanical transducer 1 of the integrated lamination type was observed. The observation position is the center of the cross section taken along the line AA in FIG. The cross-section observation was performed using Cu and O
Of the distribution of the acceleration was 20 kV, the current was 1
The measurement was performed under the conditions of × 10 ^-7 A, 256 × 256 pixels, 20 ms per pixel, and magnification of 700 times.

FIGS. 5 to 13 schematically show the observation results. In the figure, the relatively high density portions are indicated by hatching. The upper part of each figure shows the distribution of Cu, and the lower part shows the distribution of O at the same position. Figure 1
As can be seen from FIGS. 1 to 13, in the case of samples 7 to 90, the electrode layer is largely lost and the conductive base metal material Cu is segregated in the ceramic layer. In contrast, FIGS.
As can be seen from FIG. 10, in the case of samples 1 to 6, no or little Cu segregation was observed in the ceramic layer. This indicates that Ca as a melting inhibitor
It was found that the segregation of Cu can be suppressed by adding O or MgO or SrO as a melting point increasing substance to the electrode paste material.

Embodiment 6 In this embodiment, using the paste materials of Samples 1 to 3 and Sample 7 in Embodiment 5 and the same procedure as in Embodiment 5 except for the partial pressure of oxygen at 950 ° C. during firing. A layer laminate was produced. The oxygen partial pressure at 950 ° C. was adjusted to about 10 ⁻⁵ atm. As a result of observing the cross section of the obtained electromechanical transducer, it was possible to suppress the segregation of the component element Cu in the element part only in the laminate made of the CaO-added paste material as in the fifth embodiment.

Embodiment 7 In this embodiment, in Embodiment 6, the temperature is raised to 950 ° C. during firing.
Oxygen partial pressure ^-6Change it to about atm and adjust
Was. As a result, a laminated body made of the paste material of Sample 7 was obtained.
However, no segregation of the component element Cu was observed. Above, actual
CuO paste composition and oxygen during firing from Embodiments 5 to 7
By controlling the partial pressure, Cu is localized in the ceramic layer.
A laminated body without electrodeposition and with continuous electrodes was obtained.
I found out.

Embodiment 8 This embodiment is an example of an injector 5 in which an electromechanical transducer having basically the same configuration as the electro-mechanical transducer 1 of the first embodiment is used as a fuel injection actuator. Show. As shown in FIG. 14, the injector 5 of this example is applied to a common rail injection system of a diesel engine. As shown in the drawing, the injector 5 is fixed to an upper housing 52 in which the laminated integral firing type electromechanical transducer 1 is housed as a driving portion, and is fixed to a lower end thereof, and an injection nozzle portion 54 is formed therein. It has a lower housing 53.

The upper housing 52 has a substantially cylindrical shape, and the laminated and integrally fired electromechanical transducer 1 is inserted and fixed in a vertical hole 521 eccentric to the center axis. A high-pressure fuel passage 522 is provided in parallel to the side of the vertical hole 521, and the upper end thereof communicates with an external common rail (not shown) through a fuel introduction pipe 523 projecting upward from the upper housing 52. .

A fuel outlet pipe 525 communicating with the drain passage 524 protrudes from the upper portion of the upper housing 52, and the fuel flowing out of the fuel outlet pipe 525 is returned to a fuel tank (not shown). The drain passage 524 is provided with the vertical hole 52.
1 through a gap 50 between the drive unit 1 and the drive unit (laminated integrated firing type electromechanical transducer), and further through a passage (not shown) extending downward from the gap 50 through the upper and lower housings 52, 53. It communicates with the valve 551.

The injection nozzle 54 is provided with a piston body 53.
1, a nozzle needle 541 that slides in a vertical direction, and a fuel reservoir 54 that is opened and closed by the nozzle needle 541.
2 is provided with injection holes 543 for injecting high-pressure fuel supplied from the engine 2 into each cylinder of the engine. The fuel reservoir 542 is provided around an intermediate portion of the nozzle needle 541, and the lower end of the high-pressure fuel passage 522 is opened here. The nozzle needle 541 receives the fuel pressure in the valve opening direction from the fuel reservoir 542 and also has a back pressure chamber 54 provided facing the upper end surface.
When the fuel pressure is received from the back pressure chamber 544, the nozzle needle 541 is lifted, the nozzle hole 543 is opened, and the fuel is injected.

The pressure in the back pressure chamber 544 is increased or decreased by a three-way valve 551. The three-way valve 551 is configured to selectively communicate with the back pressure chamber 544 and the high pressure fuel passage 522 or the drain passage 524. Here, a ball-shaped valve body that opens and closes a port communicating with the high-pressure fuel passage 522 or the drain passage 524 is provided. This valve element is connected to the drive unit 1
Accordingly, the piston is driven via a large-diameter piston 552, a hydraulic chamber 553, and a small-diameter piston 554 disposed below.

The drive section 1 of this embodiment, that is, the electro-mechanical transducer 1 of the integrated lamination type is provided with an extendable mechanism below the electro-mechanical transducer of the integrated lamination type in the first embodiment, and the whole is provided. It is covered with a metal case (not shown). In addition, in the injector 5 of the present embodiment, since the laminated integrated firing type electromechanical transducer 1 having the above-described configuration having the Cu-based electrode is used, excellent durability and low cost can be obtained.

The electromechanical transducer of the present invention is not limited to the above-described injector, but may be a piezoelectric element for an ultrasonic motor (not shown) or a piezoelectric transformer for a piezoelectric inverter 7 shown in FIG. 71 and the like.

Embodiment 9 Table 3 shows the rigidity and volume resistivity of various metal materials. According to the table, Cu and Al have a rigidity of 160 GPa.
The following can be used as the electrode of the electromechanical transducer of the present invention. However, if a material other than Cu or Al can be alloyed to satisfy the rigidity of 160 GPa, other materials may be used. Is possible. In addition, from the table, it was found that Cu or an alloy containing Cu is very excellent as an electrode material because Cu has a volume resistivity close to that of Ag and has excellent conductivity.

[0059]

[Table 3]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a laminated integrated firing type electromechanical conversion element according to a first embodiment.

FIG. 2 is a perspective developed view showing a laminated state of a ceramic layer and an internal electrode layer in the first embodiment.

FIG. 3 is a perspective developed view showing a laminated state of a ceramic layer and an internal electrode layer in a fifth embodiment.

FIG. 4 is a perspective view showing a laminated integral firing type electromechanical conversion element according to a fifth embodiment.

FIG. 5 shows Cu,
Explanatory drawing showing O distribution.

FIG. 6 is a graph showing the relationship between Cu,
Explanatory drawing showing O distribution.

FIG. 7 is a graph showing the relationship between Cu,
Explanatory drawing showing O distribution.

FIG. 8 shows Cu,
Explanatory drawing showing O distribution.

FIG. 9 shows Cu, Cu,
Explanatory drawing showing O distribution.

FIG. 10 is a graph showing C in the case of sample 6 in the fifth embodiment.
Explanatory drawing showing a u and O distribution.

FIG. 11 is a graph showing C of Sample 7 in Embodiment 5;
Explanatory drawing showing a u and O distribution.

FIG. 12 is a graph showing C in the case of sample 8 in the fifth embodiment.
Explanatory drawing showing a u and O distribution.

FIG. 13 is a graph showing C in the case of sample 9 in the fifth embodiment.
Explanatory drawing showing a u and O distribution.

FIG. 14 is an explanatory diagram showing a structure of an injector according to an eighth embodiment.

FIG. 15 is an explanatory diagram showing a piezoelectric inverter in an eighth embodiment.

[Explanation of symbols]

 1. . . 9. An integrated electromechanical conversion element of a sintering type, . . 10. piezoelectric actuator, . . 1. ceramic layer (piezoelectric layer); . . Electrode layer, 21, 22,. . . 4. internal electrode (electrode layer); . . Injector, 7. . . Piezoelectric inverter,

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 41/187 H01L 41/08 A (72) Inventor Hitoshi Shindo 14 Iwatani Shimowasukamachi, Nishio-shi, Aichi Pref. (72) Inventor Atsuhiro Kakutani Awahiro, Nishio City, Aichi Prefecture 14 Iwatani, Ichigaya F-term (reference) CC68T CC68U CC69 CC70 CD15 CD17 CD18 CD28 CD30 CE13 CE27 CE31 4G031 AA11 AA12 AA17 AA18 AA32 AA39 BA10 CA03

Claims (10)

[Claims] 1. A laminated integrated firing type electric machine having a multilayer structure obtained by integrally firing a plurality of ceramic layers made of piezoelectric ceramics or electrostrictive ceramics and an internal electrode layer interposed between the ceramic layers. In the conversion element, the internal electrode layer is mainly composed of a base metal having a rigidity of 160 GPa or less. 2. The electromechanical transducer according to claim 1, wherein the displacement of the electromechanical transducer at the time of driving is 0.06 to 0.15%. 3. An electromechanical transducer according to claim 1, wherein said electrode layer has an average thickness of 1 to 8 μm. 4. The method according to claim 1, wherein:
An electromechanical conversion element of a laminated monolithic firing type, wherein an electrode formation ratio represented by a ratio of an electrode formation portion to a total length of the internal electrodes exposed on a cut surface in a lamination direction of the laminate is 75% or more. 5. The method according to claim 1, wherein:
A main component of the electrode layer is Cu, a Cu alloy, or an oxide thereof. 6. The method according to claim 5, wherein the electrode layer further comprises C
2. The electro-mechanical transducer according to claim 1, wherein said electromechanical transducer comprises at least one of a, Mg, and Sr. 7. The method according to claim 1, wherein:
The ceramic layer is mainly composed of PZT, which is a Pb (Zr, Ti) O ₃ -based oxide having a perovskite structure, and is a laminated monolithic electromechanical transducer. 8. The method according to claim 7, wherein the PZT is Mo.
Alternatively, a laminated and integrally fired electromechanical transducer comprising at least one kind of W. 9. The method according to claim 1, wherein:
The above electromechanical transducer is used for any one of an actuator, a piezoelectric transformer, and an ultrasonic motor. 10. The electromechanical conversion element according to claim 1, wherein the electromechanical conversion element is used for a fuel injection actuator in an injector.