CN1871716A - Multilayer piezoelectric element and jet device using same - Google Patents

Abstract

A multilayer piezoelectric device with excellent reliability and excellent durability is disclosed wherein variations in displacement are small even when the device is used under high-field, high-pressure conditions and changes in the amount of displacement are small even when the device is continuously driven for a long time. The multilayer piezoelectric device comprises a multilayer body composed of piezoelectric layers and internal electrodes alternately stacked upon one another, and external electrodes respectively formed on a first lateral surface and a second lateral surface of the multilayer body. One of every two adjoining internal electrodes is connected to one external electrode on the first lateral surface, while the other internal electrode is connected to the other external electrode on the second lateral surface. In this multilayer piezoelectric device, the rate of change of the displacement amount after continuous driving of not less than 1 x 10<9> times relative to the displacement amount before the continuous driving is within 5%.

Description

Laminate type piezoelectric element and the injection apparatus that uses it

Technical field

The present invention relates to laminate type piezoelectric element and injection apparatus, for example, relate to the fuel injection device of lift-launch in automobile engine, liquid injection apparatus such as ink-jet, driving element on precision positioning device such as Optical devices or the anti-locking apparatus of vibration etc., and carry at combustion pressure sensor, seismological sensor, acceleration transducer, load sensor, ultrasound sensors, voltage sensitive sensor, sensor element on the yaw rate sensor etc., and piezoelectric gyroscope, Piezoelectric switches, piezoelectric transformer, the laminate type piezoelectric element and the injection apparatus that use on the circuit element of piezoelectricity circuit breaker etc.

Background technology

In the past, as laminate type piezoelectric element, known had an alternatively lamination-type piezo actuator of stacked piezoelectric body and electrode.The lamination-type piezo actuator is categorized as and burns till type simultaneously, alternatively two kinds of the stacked type of stacked piezoelectric pottery and internal electrical pole plate, but in the low pressure electrification, reduce the aspect of manufacturing cost, the lamination-type piezo actuator that burns till type simultaneously shows superiority.In addition, this lamination-type piezo actuator that burns till type simultaneously helps thin layerization and durability.

Fig. 7 is the profile of the example of the existing lamination-type piezo actuator of expression.This lamination-type piezo actuator, by piezoelectrics 51 and internal electrode 52 alternatively the inertia protection portion 55 of the both ends of the surface of the driving laminate part 53 of lamination and its stack direction of being arranged on constitute.In this example, internal electrode 52 is in the side, and expose in the side that drives laminate part 53 end of the side wherein in two internal electrodes 52 of adjacency, and the opposing party's end insulated body 61 linings.And the side of the driving laminate part of exposing in the end of internal electrode 52 53 is formed with outer electrode 70, and the end not internal electrode 52 of insulated body 61 coverings is connected in this outer electrode.

In addition, Fig. 8 represents other the section of example of existing laminate type piezoelectric element.In this example, piezoelectrics 51 and internal electrode 52 be lamination alternatively, but internal electrode 52a is not formed on main looking on the whole, and forms so-called localizing electrode structure.By internal electrode 52, form the structure that 52 alternating floors of internal electrode and the side that is formed on laminate type electronic component alternatively are connected with different this localizing electrode's structure of mode lamination in the left and right sides.Also have, under situation about using, also lead (not shown) is fastened on outer electrode 54 by scolding tin as the lamination-type piezo actuator.

The laminate type piezoelectric element of this Fig. 8 also is made of the driving laminate part 63 of alternatively stacked piezoelectric body 51 and internal electrode 52 and the inertia protection portion 62 that is arranged on the both ends up and down of its stack direction.Usually electrode layer is not contained in this inertia protection portion 62; but for prevent from when burning till to drive produce between laminate part 63 and the inertia protection portion 62 shrink poor; produce stress; or generation crack; in crack that the inertia protection portion 62 superimposed layers electrode layer identical with driving laminate part 63 prevents to produce when burning till the crack that the back produces or using (reference example as, patent documentation 4).

The method manufacturing of this laminate type piezoelectric element by the following stated (reference example as, patent documentation 1), that is: on ceramic base material multi-layer sheet (ceramic green sheet) as piezoelectrics, with the pattern printing of the electrode structure that becomes regulation internal electrode paste as internal electrode, make that many of laminations are coated with the substrate (green sheet) of this internal electrode paste and the lamination formed body that obtains, it is burnt till, and will be as the conductive paste burn-back of outer electrode in the side.

In addition,,, burn till piezoelectrics 51 and internal electrode 52 in addition simultaneously, so the metal of internal electrode 52 composition is set as silver-colored 70 weight %, palladium is 30 weight % (reference example such as patent documentations 2) owing to use the alloy of silver and palladium as internal electrode 52.

Yet therefore little with the engaging force of piezoelectrics because internal electrode is metal, in addition, the generation of the internal stress that thermal expansion difference causes causes producing the crack on the interface of internal electrode and piezoelectrics, under the serious situation, the problem that laminated body is destroyed takes place also.Thereby, in order to address this problem, in patent documentation 3 for example, to have put down in writing by ceramic powders and be mixed in the method that internal electrode increases the bond strength of piezoelectrics and internal electrode.

In recent years, in small-sized piezo actuator, under big pressure, guarantee big displacement, usually, apply higher electric field, long-time continuous drives.

Patent documentation 1: the spy opens clear 61-133715 communique

Patent documentation 2: open flat 1-130568 communique in fact

Patent documentation 3: the spy opens flat 4-299588 communique

Patent documentation 4: the spy opens flat 9-270540 communique

Yet in general, the displacement of piezoelectrics changes according to the ambient temperature of using, and therefore, exists because component temperature rises, and causes the problem of the displacement variation of piezo actuator.In addition, take place because the variation of the displacement in driving, and cause variation, produce the problem that power supply is increased one's load the load change of the power supply of control voltage.In addition, if the rate of change of displacement is big, the rapid deterioration of displacement self not only then, and under the situation of rising greater than heat dissipation capacity in the temperature of element, then exist and thermal runaway takes place, the problem that causes element to destroy.

In order to suppress the rising of this component temperature, use the little internal electrode of resistivity comparatively effective.Yet, the resistivity value of a silver-colored palldium alloy compare silver owing to its ratio of components or the resistivity of palladium monomer high significantly, exist in silver-colored 70 weight %, palladium and be 1.5 times the problem that resistance in the composition of palladium-silver of 30 weight % reaches the palladium monomer.And if the sintered density of internal electrode is low, then resistance is higher.

In addition, in existing laminate type piezoelectric element,, cause the deviation of displacement to become big problem because the internal electrode part than piezoelectrics softness, therefore exists the part of the displacement that is taken place by piezoelectrics to be absorbed.In addition, durability, also become problem, also exist in for a long time use repeatedly after, the deviation of displacement becomes big problem.These problems by as shown in above-mentioned patent documentation 3, in internal electrode 52, mix the method that ceramic powders improves the bond strength between internal electrode 52 and the piezoelectrics 51 and can not solve.

That is, in recent years,, guarantee the big displacement under the big pressure, and apply higher electric field, its long-time continuous is driven, but in this case, exist use during the initial stage, the problem of the deviation of the displacement of each actuator in order to make actuator's miniaturization.In addition, the problem that also has the variation of the displacement under the operation for a long time.

In addition, lamination-type piezo actuator and common laminate type electronic component (for example, laminated ceramic capacitor) difference, along with energising, the ceramic deformation of piezoelectrics.That is, the electroceramics of driving number of times and piezoelectrics distortion number of times is identical.In addition, in recent years,, wish to apply higher electric field, its long-time continuous is driven in order in small-sized lamination-type piezo actuator, under big pressure, to guarantee big displacement.

Yet, in the improvement shown in the patent documentation 4, apply higher electric field, particularly under the situation that long-time continuous drives, produce the crack, damage as the function of actuator, have problems on the durability.

Summary of the invention

Even the object of the present invention is to provide the extent of deviation of the situation bottom offset that under high electric field, high pressure, uses also little, in addition, even under the situation that its long-time continuous is driven, the variable quantity of displacement is also little, and the laminate type piezoelectric element and the injection apparatus of reliability, excellent in te pins of durability.

In order to reach above purpose, first laminate type piezoelectric element of the present invention has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode, be connected with described outer electrode in described second side, it is characterized in that

1 * 10 ⁹The rate of change with respect to the element displacement before the Continuous Drive of the element displacement after the Continuous Drive more than inferior is in 5%.

First laminate type piezoelectric element of the present invention of Gou Chenging even the Continuous Drive displacement does not change substantially yet, therefore, does not have the mistake operation of device like this, in addition, has the durability of the excellence that does not have thermal runaway.

In addition, second laminate type piezoelectric element of the present invention has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode, be connected with described outer electrode in described second side, it is characterized in that

1 * 10 ⁹The rate of change of the component resistance before the relative Continuous Drive of component resistance after the Continuous Drive more than inferior is in 5%.

Second laminate type piezoelectric element of the present invention as described above because the maximum rate of change of the component resistance after the Continuous Drive is in 5%, therefore, does not have the mistake operation of device, has the durability of the excellence that does not have thermal runaway in addition.

In first and second laminate type piezoelectric elements of the present invention, the maximum rate of change of the element displacement in the preferred Continuous Drive is in 5%, and thus, mistake operation that can more effective anti-locking apparatus can have the more excellent durability that does not have thermal runaway.

In first and second laminate type piezoelectric elements of the present invention, preferred 1 * 10 ⁹The size changing rate of the gauge of the piezoelectric body layer before the relative Continuous Drive of gauge of the piezoelectric body layer after the Continuous Drive more than inferior is in 5%.

Like this, because the size changing rate before and after the driving of piezoelectrics is in 5%, therefore, mistake operation that can more effective anti-locking apparatus can have the more excellent durability that does not have thermal runaway.

In first and second laminate type piezoelectric elements of the present invention, the maximum rate of change of the component resistance in the preferred Continuous Drive is in 5%.

Like this, because the maximum rate of change of component resistance in the Continuous Drive is in 5%, therefore, mistake operation that can more effective anti-locking apparatus can have the more excellent durability that does not have thermal runaway.

The 3rd lamination-type piezoelectric element of the present invention has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode is connected with outer electrode in second side, it is characterized in that

Be provided with post, described post runs through described internal electrode, and binding clips this internal electrode subtend laminate type piezoelectric element piezoelectric body layer.

The 3rd lamination-type piezoelectric element of the present invention of Gou Chenging by the post that links between the piezoelectrics is set, can reduce the extent of deviation of displacement in internal electrode like this.In addition, even after long continuously operation, the variation of displacement is also little, thereby, height reliability can be provided and improve the piezo actuator of durability.Thereby, excellent in te pins of durability, the injection apparatus of height reliability for example can be provided.

In the 3rd lamination-type piezoelectric element of the present invention, the diameter of the bonding part of preferred above-mentioned post and piezoelectric body layer is that the number more than 50% of the maximum gauge of post accounts for more than 30% of all numbers.

In addition, in the 3rd lamination-type piezoelectric element of the present invention, the mean value of the minimum diameter of preferred above-mentioned post is more than the 0.2 μ m.

In addition, in the 3rd lamination-type piezoelectric element of the present invention, there are 5～150 in preferred above-mentioned post in 1mm.

Also have in addition, in the 3rd lamination-type piezoelectric element of the present invention, the piezoelectrics material coefficient of thermal expansion difference of preferred above-mentioned post and the described piezoelectric body layer of formation is 3 * 10 ^-5/ ℃ below.

In addition, in the 3rd lamination-type piezoelectric element of the present invention, preferred above-mentioned post is by constituting with piezoelectrics material identical materials.

In addition; in first～the 3rd lamination-type piezoelectric element of the present invention that constitutes as described above; preferred described laminated body comprises the alternatively inertia protection portion of the described piezoelectric body layer of lamination and absentee layer thereon down; be made as A in beeline from the side of the outer thoughtful described inertia protection portion of described absentee layer; when protecting the width of portion to be made as B inertia, A/B is 0.01～0.08.

At this, above-mentioned turn-off is meant on the face of cutting protection portion with the direction vertical with stack direction length measured respectively from A, and the width B of inertia protection portion is a length measured on the direction identical with the direction of measuring this beeline A.

Laminate type piezoelectric element according to such formation; by making the contraction of burning till even; and suitable engaging zones is set between piezoelectric body layer; can reduce inertia protection portion and drive the stress that produces between the laminate part; therefore; even under the situation of high voltage, continuous use for a long time, also can improve durability, thereby the injection apparatus of the laminate type piezoelectric element with excellent in te pins of durability can be provided.

That is, the inventor is through researching and developing the beeline and the durability of the side of thoughtful inertia protection portion outside absentee layer, and it found that the relation between this beeline and the durability.In a word, found by controlling to absentee layer inertia protection portion till beeline can further improve durability.

In having the laminate type piezoelectric element of the present invention of this absentee layer, preferred described absentee layer contains metal.

In addition, preferred described absentee layer is made of the material identical with described internal electrode.

In addition, described absentee layer preferably contains metal oxide, nitride, reaches any inorganic composition in the carbide, and more preferably described absentee layer contains the above inorganic composition of 2wt%.

The thickness of preferred described piezoelectric body layer is more than the 50 μ m.

In addition, in first～the 3rd lamination-type piezoelectric element of the present invention that constitutes as described above, the metal constituent in the preferred described internal electrode with VIII family metal and/or Ib family metal as main component.

Like this, by make metal constituent in the described internal electrode with VIII family metal and/or Ib family metal as main component, can be shaped as described internal electrode by metal group, therefore, can burn till simultaneously with the high described piezoelectric body layer of firing temperature with highly heat-resistant.

Like this, internal electrode with VIII family metal and/or Ib family metal as first of main component～the 3rd lamination-type piezoelectric element in, preferably be made as M1 (weight %) at content with the VIII family metal in the described internal electrode, when the content of Ib family metal is made as M2 (weight %), satisfy 0＜M1≤15,85≤M2＜100, M1+M2=100.So, then can reduce the resistivity of described internal electrode, therefore,, also can suppress the heating of described internal electrode even long-time continuous drives laminate type piezoelectric element.And the temperature that can suppress laminate type piezoelectric element rises, and therefore, can make element displacement stabilisation.

In addition, in laminate type piezoelectric element of the present invention, preferred described VIII family metal is more than at least a among Ni, Pt, Pd, Rh, Ir, Ru, the Os, and Ib family metal is more than at least a among Cu, Ag, the Au.As the raw material of described internal electrode,, then can use any of alloy raw material and mixed powder raw material if select from such scope.

In addition, if described VIII family metal is more than at least a among Pt, the Pd, Ib family metal is more than at least a among Ag, the Au, then can form the described internal electrode of thermal endurance and oxidative resistance excellence.

In addition, because described VIII family metal is Ni, can relax the stress that the displacement when driving produces, and can form the described internal electrode of excellent heat resistance.

In addition, because described Ib family metal is Cu, can relax the stress that the displacement when driving produces, and can form the described internal electrode of conductivity of heat excellence.

In addition, owing to add oxide, nitride or carbide when in described internal electrode, adding the metal constituent, increase the tight constant intensity at the interface of described internal electrode and described piezoelectrics, therefore, can suppress peeling off of described internal electrode and described piezoelectrics.

In addition, preferred described oxide will be by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is as main component.

In addition, preferred described piezoelectric body layer with perofskite type oxide as main component.

In addition, preferred described oxide will be by PbZrO ₃-PbTiO ₃Therefore the perofskite type oxide that constitutes, can burn till described piezoelectrics and described internal electrode simultaneously as main component, therefore, can shorten firing process, and can reduce the resistivity of described internal electrode.

In addition, the firing temperature of preferred described laminated body is more than 900 ℃ but below 1000 ℃.

In addition,, flexible that the driving of laminate type piezoelectric element causes can be cooperated, peeling off of internal electrode can be suppressed because departing from before and after burn till of the composition in the described internal electrode is below 5%.

In addition in addition, in first～the 3rd lamination-type piezoelectric element of the present invention, preferably expose described internal electrode in described laminated body by the end, the described internal electrode that does not expose with the end alternatively constitutes, described piezoelectric body layer between described internal electrode that does not expose described end and described outer electrode partly is formed with groove, is filled with the Young's modulus insulator littler than described piezoelectric body layer in this groove.

In addition, in first～the 3rd lamination-type piezoelectric element of the present invention, preferred described internal electrode contains the space, and the long-pending area ratio of the entire profile that the space accounts for the section of described internal electrode is 5～70%.So, piezoelectrics restraining force to internal electrode by electrical field deformation the time is died down, can increase the displacement of piezoelectrics.In addition, because the space, the stress that internal electrode is applied relaxes, thereby, there is the advantage that improves durability.In addition, in the heat transfer in element, internal electrode is in superiority, if but internal electrode has the space, then relax the variations in temperature of the element internal that the rapid variations in temperature of element-external causes, therefore can access the strong element of heat shock resistance.

Injection apparatus of the present invention is characterized in that, has: the accepting container with spray-hole; Be housed in any laminate type piezoelectric element among first of this accepting container～3rd; By the valve of this laminate type piezoelectric element from described spray-hole ejection liquid.

Thus, can provide durability high injection apparatus.

Description of drawings

Figure 1A is the stereogram of expression laminate type piezoelectric element of the present invention.

Figure 1B is the three-dimensional expanded view of the layer-by-layer state of expression piezoelectric body layer of laminate type piezoelectric element of the present invention and interior electrode layer.

Fig. 2 A is the stereogram of the laminate type piezoelectric element of embodiments of the present invention 2.

Fig. 2 B is the end view of the laminate type piezoelectric element of execution mode 2.

Fig. 3 is the cutaway view of part of the section of the expression laminate type piezoelectric element that amplifies execution mode 2.

Fig. 4 A is the stereogram that the outside of externally electrode forms the laminate type piezoelectric element of conductivity accessory.

Fig. 4 B is the profile that the outside of externally electrode forms the laminate type piezoelectric element of conductivity accessory.

Fig. 5 A is the stereogram of the laminate type piezoelectric element of embodiments of the present invention 3.

Fig. 5 B be the laminate type piezoelectric element of expression execution mode 3 piezoelectric layer, interior electrode layer, protection portion, and the layer-by-layer state of absentee layer cutaway view.

Fig. 6 is the end view of expression injection apparatus of the present invention.

Fig. 7 is the end view of existing lamination-type piezo actuator.

Fig. 8 represents the part of the section of existing laminate type piezoelectric element.

Among the figure, the 1-piezoelectrics; The 2-internal electrode; The 3-insulator; The 4-outer electrode; 13-drives laminate part; 14,20-inertia protection portion; The 18-post; The 21-absentee layer; The bonding part of 22-post and piezoelectrics; The 31-accepting container; The 35-needle-valve; The 37-fuel passage; The 39-cylinder; The 41-piston; The 43-piezo actuator.

Embodiment

Below, with reference to drawing, embodiments of the present invention are described.

(execution mode 1)

Figure 1A is the stereogram of structure of the laminate type piezoelectric element of expression embodiments of the present invention 1, and Figure 1B is the three-dimensional expanded view of the layer-by-layer state of expression piezoelectric body layer 1 and interior electrode layer 2.

The laminate type piezoelectric element of present embodiment 1, shown in Figure 1A, B, the laminated body of the four side column shapes that formed by the alternatively a plurality of piezoelectric body layers 1 of lamination and a plurality of internal electrode 2 and the outer electrode that forms with an alternating floor ground and internal electrode 2 ways of connecting on its side 4 constitute.

Specifically, expose in the side that is formed with outer electrode 4 in the mode of an alternating floor end that constitutes internal electrode 2, so that the end of the internal electrode 2 that exposes and outer electrode 4 conductings.Also have, in laminated body, the part of diacritic 14 is inertia protection portions of not containing the stacked piezoelectric body layer 1 of internal electrode.Also have, under the situation that the laminate type piezoelectric element with present embodiment 1 uses as the lamination-type piezo actuator, lead can be fastened on the outer electrode 4 with scolding tin, and described lead is connected the external voltage supply unit.

Be furnished with internal electrode 2 between piezoelectric body layer 1, this internal electrode 2 applies the voltage of regulation to each piezoelectric body layer 1, and the displacement that inverse piezoelectric effect causes takes place on piezoelectric body layer 1 and forms, and for example, is formed by metal materials such as silver-palladiums.

In addition, inertia protection portion 14 is made of a plurality of piezoelectric body layers 1 that are not equipped with internal electrode 2, also can displacement even inertia protection portion 14 is applied voltage.

And, the laminate type piezoelectric element of present embodiment 1, even under situation about driving repeatedly continuously, the rate of change of the element displacement before and after driving is also in 5%.That is, the laminate type piezoelectric element of present embodiment 1 is because the rate of change of the element displacement before and after the Continuous Drive is suppressed in 5%, and therefore, durability is high.

At this, the rate of change of the component variation amount before and after the Continuous Drive is meant after making laminate type piezoelectric element, the ratio of the displacement of the variation of the displacement after driving repeatedly before to continuous use.

Specifically, at first, after making laminate type piezoelectric element, before using continuously, laminate type piezoelectric element is applied certain voltage obtain displacement (initial stage displacement).

Secondly, laminate type piezoelectric element is applied alternating voltage arbitrarily, Continuous Drive 1 * 10 ⁹After about inferior, apply and the initial stage of measuring identical direct voltage during displacement, the displacement when obtaining this (displacement after the Continuous Drive).

And, calculate the rate of change of the relative initial stage displacement of displacement after the Continuous Drive, with the rate of change of this rate of change as the element displacement before and after the Continuous Drive.

That is, the rate of change of the element displacement before and after the Continuous Drive is obtained by following formula.

{ 100 * (displacement after the Continuous Drive-initial stage displacement)/(initial stage displacement) } %

In addition, in the laminate type piezoelectric element of present embodiment 1, the maximum rate of change that constitutes the element displacement in the Continuous Drive is in 5%.This is because if the maximum rate of change of the element displacement in the Continuous Drive of laminate type piezoelectric element surpasses 5%, laminate type piezoelectric element deterioration in driving sometimes then, and the durability of laminate type piezoelectric element descends.

At this, the maximum rate of change of the element displacement in the Continuous Drive is meant and laminate type piezoelectric element is being applied certain direct voltage, and the amount of the displacement that causes this moment is made as displacement (displacement under the A-stage) before the Continuous Drive, secondly, laminate type piezoelectric element is applied and the identical alternating voltage of direct voltage that applies in order to measure the displacement under the A-stage, and Continuous Drive 1 * 10 ⁸The displacement of measuring in each circulation about inferior is made as maximum displacement in the Continuous Drive with the maximum of wherein displacement, the ratio that the displacement of this maximum displacement before by described relatively Continuous Drive changes.

At this, the situation of Continuous Drive is illustrated to applying alternating voltage, even but under the situation of using the pulse voltage Continuous Drive, the maximum rate of change of the element displacement in the Continuous Drive is in 5%.For example, laminate type piezoelectric element is applied the direct voltage of 150V, and displacement that will this moment is made as the displacement under the A-stage, secondly, the pulse voltage by 0V and 150V makes laminate type piezoelectric element Continuous Drive 1 * 10 ⁸After about inferior, when measuring the displacement of each pulse, in the element of the present invention, the maximum of displacement wherein is in 5%.

Also have, being used to measure the direct voltage of A-stage and alternating voltage or pulse voltage can set arbitrarily between for example 0V～200V.

In addition, in laminate type piezoelectric element of the present invention, the gauge rate of change of the piezoelectrics before and after the Continuous Drive is in 5%.This is because if the gauge rate of change of the piezoelectrics before and after the Continuous Drive of laminate type piezoelectric element surpasses 5%, the size self of the laminate type piezoelectric element before and after then driving changes, therefore, its result makes the displacement change, so the deterioration of laminate type piezoelectric element increases, the durability of laminate type piezoelectric element significantly descends.

At this, the gauge rate of change before and after the driving of piezoelectrics is meant and is applying alternating voltage arbitrarily and Continuous Drive 1 * 10 to laminate type piezoelectric element ⁸After about inferior, the ratio that the gauge of the piezoelectrics before the relative Continuous Drive of gauge of the piezoelectrics of laminate type piezoelectric element on stack direction changes.

In addition, the gauge rate of change of piezoelectrics, utilize microscopic examination such as SEM to drive before the side of laminate type piezoelectric elements, and measure the gauge of the piezoelectrics at 10 places arbitrarily and calculate mean value, and after driving, calculate mean value by the gauge of measuring same place and obtain.

In addition, in the laminate type piezoelectric element of present embodiment 1, the rate of change of the component resistance before and after the Continuous Drive of laminate type piezoelectric element is in 5%.This is that then the deterioration of laminate type piezoelectric element becomes seriously because if the rate of change of the component resistance before and after the Continuous Drive of laminate type piezoelectric element surpasses 5%, and the durability of laminate type piezoelectric element significantly descends.

At this, the rate of change of the component resistance before and after the Continuous Drive is meant and laminate type piezoelectric element is being applied direct voltage arbitrarily, and the resistance value of the element that will measure this moment is made as the preceding component resistance of Continuous Drive, secondly, laminate type piezoelectric element is applied alternating voltage arbitrarily, and Continuous Drive 1 * 10 ⁹After about inferior, the resistance value of element of this moment is made as under the condition of the component resistance after the Continuous Drive ratio that the component resistance before the described relatively Continuous Drive of the component resistance after this Continuous Drive changes.

In addition, the laminate type piezoelectric element of execution mode 1, the maximum rate of change of the element in the Continuous Drive is in 5%.This is that then the deterioration of laminate type piezoelectric element becomes seriously because if the maximum rate of change of the component resistance in the Continuous Drive of laminate type piezoelectric element surpasses 5%, and the durability of laminate type piezoelectric element significantly descends.

At this, the maximum rate of change of the element in the Continuous Drive is meant and laminate type piezoelectric element is being applied direct voltage arbitrarily, and the resistance value of the element that will measure this moment is made as the preceding component resistance of Continuous Drive, secondly, laminate type piezoelectric element is applied alternating voltage arbitrarily, and with Continuous Drive 1 * 10 ⁸The maximum resistance of the component resistance in the process about inferior is made as under the condition of the component resistance in the Continuous Drive, the ratio that the component resistance before the described relatively Continuous Drive of the component resistance in this Continuous Drive changes.

For in aforesaid laminate type piezoelectric element of the present invention, with the component variation amount in Continuous Drive front and back or the Continuous Drive, and the gauge rate of change of the piezoelectrics before and after the Continuous Drive, also have the rate of change of the component resistance in Continuous Drive front and back or the Continuous Drive to be located in 5%, can carry out setting as described below.

Before, as the method for the variation of the gauge rate of change of suppression element displacement, piezoelectrics or component resistance, use the constant method of the component temperature that keeps in the Continuous Drive or according to component temperature fine setting controlling and driving voltage method always.Specifically, controlling and driving voltage when monitoring component temperature, or, the fin of active heat removal is installed for the control element peripheral temperature.

To this, in embodiments of the present invention 1, the component temperature in the Continuous Drive (suppression element variation of temperature) has been controlled in the heating of the element self that causes by controlling and driving.In order to control described component temperature (suppression element variation of temperature), need reduce the inductive loss (tan δ) of piezoelectric body layer 1, or reduce component resistance.

In addition, because the gauge of piezoelectrics changes according to degree of polarization, therefore, for the gauge rate of change that keeps the piezoelectrics before and after the Continuous Drive constant, need reduce the inductive loss (tan δ) of piezoelectrics, so that the polarized state before and after the Continuous Drive is identical.In addition, if the polarized state before the temperature of piezoelectrics than the temperature height of Curie point, then drives and drive in polarized state change, cause the gauge or the displacement of the piezoelectrics before and after the Continuous Drive to change easily, therefore, need the rising of suppression element temperature.Therefore, the temperature of element self rises in the time of need suppressing to drive by the resistivity that reduces electrode material.

For example, with PbZrO ₃-PbTiO ₃Deng perofskite type oxide form under the situation of piezoelectric body layer 1 as main component, in order to reduce inductive loss (tan δ), have and crossing the method for burning till laminated body under the oxygen atmosphere or in the processing after the burning till of laminated body, slowing down and burn till the method for the speed of speed cooling from maximum.Specifically, cooling rate can be made as below 600 ℃/hour, preferably be made as below 300 ℃/hour.In addition,, can be lower than 1.5%, preferably be made as below 0.5% as inductive loss (tan δ).

In addition,,, can select the material of the little composition of resistivity value, and form the structure of the densification of guaranteeing the conductivity path as the material of internal electrode 2 in order to reduce component resistance.

In addition, the temperature characterisitic of displacement of material that wish to constitute piezoelectric body layer 1 is irrelevant and necessarily with serviceability temperature, therefore, and the preferred little piezoelectrics material of range of temperature intrinsic displacement amount of the element when Continuous Drive.

In addition, for the heat of element internal is emitted to the outside of element effectively, preferably form the internal electrode 2 of the predominating path of conduct heat transfer by composition with excellent heat conductivity.

Secondly, the manufacture method to the laminate type piezoelectric element of present embodiment 1 describes.

In this manufacture method, at first, mix: by PbZrO ₃-PbTiO ₃Calcined powder Deng the piezoelectric ceramic of the perofskite type oxide of forming; The binding agent of forming by organic polymers such as third rare system, butyral systems; DBP plasticizer such as (phthalic acid dibutyl), and make raw material (slurry).And, use this raw material, by band methods of forming such as scraping blade method or calender roll methods, create the ceramic base material multi-layer sheet of piezoelectric body layer 1.

Secondly, in the metal dust of formation internal electrodes such as silver-palladium, add hybrid adhesive, plasticizer etc., and make conductive paste.By silk screen printing etc., at the conductive paste of described each thickness of printing 1～40 μ m above the substrate.

And, be printed with the substrate of conductive paste above lamination is a plurality of, under the temperature of regulation, this laminated body after taking off binding agent under the temperature of regulation, is burnt till under 900～1200 ℃, make laminated body thus.

Also have, the manufacture method of laminated body is not limited to above-mentioned manufacture method, and the laminated body that constitutes so long as can make the alternatively a plurality of piezoelectric body layers 1 of lamination and a plurality of internal electrode 2 can be any manufacture method.

Also have, laminated body is made into the end of internal electrode 2 and exposes in its side in the mode of an alternating floor.In addition, can partly form groove, and in this groove at the piezoelectrics that does not expose between internal electrode 2 and outer electrode 4 end, form Young's modulus than piezoelectric body layer 1 low, insulators such as resin or rubber.At this, described groove is formed on the side of laminated body by inner cutter sweep etc.

Secondly, in glass powder, add binding agent and make silver-colored glass conductive paste, make it be configured as sheet, and dry (the former density of control strip is 6～9g/cm ³, solvent is dispersed), the outer electrode that this sheet is replicated in the column laminated body forms face.And, in temperature higher than the softening point of glass and below silver point (965 ℃), and be firing temperature (℃) the temperature below 4/5 under, carry out burn-back.Thus, use silver-colored glass conductive paste to make the disappearance of dispersing of binding agent composition in the sheet of making, be formed with the outer electrode 4 that porous matter electric conductor with three dimensional network ocular structure constitutes.

Constitute the conduction material of outer electrode 4, from absorbing the stress this point by the flexible generation of actuator fully, preferred low silver or the silver of Young's modulus is the alloy of main component.

In addition, the burn-back temperature of described silver-colored glass conductive paste, in order to form effective neck, and make silver and internal electrode 2 diffusion bond in the silver-colored glass conductive paste, in addition, in order effectively to keep the space in the outer electrode 4, in addition, outer electrode 4 and column laminated body lateral parts ground are engaged, and be preferably 550～700 ℃.In addition, the softening point of the glass ingredient in the silver-colored glass conductive paste is preferably 500～700 ℃.

Be higher than in the burn-back temperature under 700 ℃ the situation, excessively carry out the sintering of the silver powder of silver-colored glass conductive paste, can not form porous matter electric conductor with effective three dimensional network ocular structure.Its result might become excessively fine and close by outer electrode 4, and the Young's modulus of outer electrode 4 becomes excessive.If the Young's modulus of outer electrode 4 uprises, then owing to can not fully absorb stress when driving, therefore, outer electrode 4 might break.Be preferably at glass softening point 1.2 times and carry out burn-back under with interior temperature.

On the other hand, be lower than in the burn-back temperature under 550 ℃ the situation, therefore abundant diffusion bond between internal electrode 2 ends and the outer electrode 4, can not form neck, might cause spark between internal electrode 2 and outer electrode 4 when driving.

Also have, the thickness of the sheet of silver-colored glass conductive paste is preferably than the thin thickness of piezoelectric body layer 1.From stretching of cooperation actuator, more preferably below the 50 μ m.By forming-4 of above outer electrode, finish the laminate type piezoelectric element of execution mode 1.

In addition, form in the structure of the groove that arrives internal electrode in the side, the laminated body that forms outer electrode 4 be impregnated in silicone rubber solution, and, to the silicone rubber solution vacuum degassing, thus, to the inner filled silicon rubber of the groove of laminated body, pull laminated body out from silicone rubber solution afterwards, on the side of laminated body, coating silicon rubber.Thereafter, with fill in the groove and coating in the described silicon rubber sclerosis of the side of column laminated body, thus, finish laminate type piezoelectric element of the present invention.

Also have, lead is connected with outer electrode 4, pair of external electrodes 4 is applied the direct voltage of 0.1～3kV/mm,, thus, finish the lamination-type piezo actuator that utilizes laminate type piezoelectric element of the present invention the laminated body processing that polarizes by this lead.In this lamination-type piezo actuator, if the voltage supply unit of lead with the outside is connected, and apply voltage, then each piezoelectric body layer 1 displacement greatly owing to inverse piezoelectric effect by lead and 4 pairs of internal electrodes 2 of outer electrode.The lamination-type piezo actuator of the execution mode 1 of Gou Chenging can use for example, to the automotive fuel injection valve of engine fueling like this.

(execution mode 2)

Fig. 2 A is the stereogram of structure of the laminate type piezoelectric element of expression embodiments of the present invention 2, and Fig. 2 B is its end view, and Fig. 3 is the cutaway view of internal electrode 2 parts.

The lamination-type piezo actuator that constitutes by the laminate type piezoelectric element of present embodiment 2, shown in Fig. 2 A, 2B, by the alternatively a plurality of piezoelectric body layers 1 of lamination and a plurality of internal electrode 2 and the side of the laminated body 10 of the four side column shapes that form, the end of internal electrode 2 covers with the mode insulated body 3 of an alternating floor, with the end ways of connecting of the internal electrode 2 that covers with insulated body 3 not outer electrode 4 is set.Outer electrode 4 is the porous matter electric conductors that constitute as the conduction material and the glass of main component by with silver, and lead 6 is fastened on each outer electrode 4.

At this, particularly in the lamination-type piezo actuator of present embodiment 2, it is characterized in that, as shown in Figure 3, be provided with the post 18 of a plurality of inleakage electrodes 2, connect two piezoelectric body layers 1 of subtend by this post 18.Like this, by between piezoelectric body layer 1, for example forming post 18, thereby improve the rigidity of internal electrode 2, be suppressed at the absorption of the displacements that take place in the internal electrode 2, therefore, can access stable displacement with hard material such as pottery.Its result can reduce the deviation of the displacement of each product, and can improve each reliability of products.In addition, the variation of the displacement after long-time the use also diminishes, thereby improves durability.

In addition, as shown in Figure 3, it is total more than 30% that the diameter B of the bonding part 22 of preferred post 18 and piezoelectric body layer 1 is that the number of the post 50% or more 18 of the maximum gauge A of post 18 accounts for.This is because can obtain more stable displacement by so doing.That is, account for more than 30% because the diameter B of the bonding part 22 of post 18 and piezoelectric body layer 1 is the post 50% or more 18 of the maximum gauge A of post 18, the intensity of post 18 and piezoelectric body layer 1 becomes greatly, and rigidity also becomes big in addition.Thus, the displacement that takes place in internal electrode 2 diminishes, and makes the displacement stabilisation.Its result can further suppress the deviation of the displacement of each product, thereby can further improve reliability.In addition, the variation of the displacement after long-time the use also diminishes, thereby improves durability.In like manner, the diameter B of the bonding part 22 of post 18 and piezoelectric body layer 1 is the number of the post more than 50% 18 of the maximum gauge A of post 18, more preferably post 18 sums more than 50%.

Maximum gauge A and diameter B measure as described below.At first, near the section photograph the internal electrode 2 of as shown in Figure 3 laminate type piezoelectric element, for each post 18, measure maximum gauge A and with the diameter B of the bonding part of piezoelectric body layer 1.According to this measurement result, calculate the value of (B/A) * 100, to each post 18, obtain the ratio of the maximum gauge A of post 18 and post 18 and the diameter B of the bonding part 22 of piezoelectric body layer 1.Then, obtaining this value is a few percent that the number of the post 18 more than 50% accounts for the number of mensuration.Thus, get 10 places and obtain mean value.

In addition, in present embodiment 2, the mean value of the minimum diameter of preferred post 18 is more than the 0.2 μ m, more preferably more than the 0.3 μ m.Thus, can increase the intensity of post 18, be difficult to destroy.Therefore, can suppress the deviation of displacement, the variation of the displacement after reducing to use continuously improves reliability and durability.

In addition, in laminate type piezoelectric element of the present invention, preferably near the section internal electrode 2, there are 5～150, more preferably 10～100 at 1mm post 18.This is because be made as mentioned above by the quantity with post 18, can improve rigidity, can access the laminate type piezoelectric element of the little reliability excellence of the deviation of displacement.If the quantity of post 18 is less than 5, the effect that post then is set diminishes, and on the other hand, if post 18 is more, then the resistance of internal electrode 2 becomes big, as the function reduction of the electrode of heated by electrodes etc.

In addition, the thermal expansion difference between preferred post 18 and the piezoelectric body layer 1 is 3 * 10 ^-5/ ℃ below, be preferably 2 * 10 especially ^-5/ ℃.Thus, reduce the internal stress between piezoelectric body layer 1 and the post 18, can increase the bond strength on the interface, can improve durability.Using under the situation of PZT in piezoelectric body layer 1, is 3 * 10 as thermal expansion difference ^-5/ ℃ the material of post 18, can use PZT, Al ₂O ₃, ZrO ₂, TiO ₂, SiO ₂Deng.

In addition, preferred post 18 and piezoelectric body layer 1 are made of same material.Thus, the internal stress that produces between post 18 and piezoelectric body layer 1 becomes littler, and it is big that the bond strength on the interface becomes, thereby can improve durability.

Described post 18 can in firing process, burn till in temperature-rise period under the temperature more than 80% of maximum temperature by mix the powder of the material that forms post 18 in advance in internal electrode 2, forms more than the maintenance once.In a word, with existing burn till different, after degreasing, in once keeping more than 80% of maximum sintering temperature, the influence of the metal constituent around the powder of material that is mixed in the formation post 18 of internal electrode 2 is subjected to becomes the easy state that the grain growth takes place.Afterwards, by burning till under maximum sintering temperature, grain is grown in the mode that links between the piezoelectric body layer 1, and inleakage electrode 2 can form the post 18 that links the piezoelectric body layer 1 that clips internal electrode 2 subtends.The addition of the material powder of the post 18 that adds to internal electrode 2 is suitable at 5～40 weight %.If more than 40 weight %, then the resistance of electrode is excessive, has the possibility of heating, in addition, if less than 5 weight %, then post can not be set fully, and the effect that improves the rigidity of internal electrode diminishes, and can not improve reliability and durability fully.

Manufacture method to the laminate type piezoelectric element of present embodiment 2 describes.

At first, identical with execution mode 1, make ceramic base material multi-layer sheet as piezoelectric body layer 1.

Secondly, for example, in the metal dust of the internal electrode that constitutes palladium-Yin etc., mix PZT, the Al that adds as the material of post 18 ₂O ₃, ZrO ₂, TiO ₂, SiO ₂Deng more than any of ceramic powders and binding agent, plasticizer etc., thereby make conductive paste.By this conductive paste at described each thickness of printing 1～40 μ m above the substrate such as silk screen printing.

Then, be printed with the substrate of conductive paste above many of the laminations, under the temperature of regulation, this laminated body taken off binding agent after, after once keeping under the temperature 80% or more of maximum temperature, under maximum temperature is 900～1200 ℃, burn till.Preferably be longer than 0.25h in the retention time more than 80% of maximum temperature.In addition, the above step in two rank also can be set.For example, also can keep, with multistage pattern heating 80% and 90% time of the highest maintenance temperature.Like this, in order to promote the growth of post, need under the condition more than 80% of the highest maintenance temperature, once keep.Thus, can be securely in conjunction with the piezoelectrics of subtend.It is because be lower than under 900 ℃ the temperature below 1200 ℃ that maximum temperature is made as more than 900 ℃, can not make fine and close piezoelectrics, if surpass 1200 ℃, then cause the stress that departs from of the contraction of the contraction of the electrode when burning till and piezoelectrics to become big, produce the crack during Continuous Drive.

Thereafter, make internal electrode that the end exposes expose side at laminate type piezoelectric element in one mode at interval, form groove between internal electrode 2 that does not expose in this end and the side, in groove, form Young's modulus than piezoelectric body layer 1 low, insulators such as for example resin or rubber.This groove 3 can be by formation such as cutter sweeps.

Secondly, the method by identical with execution mode 1 forms outer electrode 4.

Then, the laminated body 10 that forms outer electrode 4 be impregnated in silicone rubber solution, and, to the silicone rubber solution vacuum degassing, thus, to the inner filled silicon rubber of the groove of laminated body 10, from silicone rubber solution laminated body 10 is proposed afterwards, on the side of laminated body 10, coating silicon rubber.Thereafter, make fill in the groove and coating in the described silicon rubber sclerosis of the side of column laminated body.

, lead with outer electrode 4 be connected, thus, finish laminate type piezoelectric element of the present invention thereafter.

And, by this lead pair of external electrodes 4 is applied the direct voltage of 0.1～3kV/mm, and, thus, finishes lamination-type piezo actuator of the present invention as product to laminated body 10 processing that polarizes.In this finished product, if the voltage supply unit of lead with the outside is connected, and apply voltage by lead and 4 pairs of internal electrodes 2 of outer electrode, then each piezoelectric body layer 1 displacement greatly owing to inverse piezoelectric effect, thus, for example can be used as, to the automotive fuel injection valve performance function of engine spray fueling.

The laminate type piezoelectric element of Gou Chenging is because the rigidity of internal electrode 2 uprises as mentioned above, and in addition, bond strength improves, and therefore, can reduce the absorption of the displacement of internal electrode.In addition,, can not peel off yet, therefore, can reduce the variation of displacement even make its Continuous Drive.Thereby can provide does not have misoperation, and has the piezo actuator of height reliability.

The laminate type piezoelectric element of present embodiment 2 is not limited to the concrete example of above-mentioned explanation, as long as in the scope that does not break away from aim of the present invention, just can carry out various changes.

(execution mode 3)

Fig. 5 A, B represent the laminate type piezoelectric element of embodiments of the present invention 3, and Fig. 5 A is a stereogram, and Fig. 5 B is the profile of representing piezoelectric layer, interior electrode layer, protection portion, reaching the layer-by-layer state of absentee layer.

The laminate type piezoelectric element of present embodiment 3, shown in Fig. 5 A, B, on the side of a pair of subtend of the laminated body 30 that forms, be respectively equipped with outer electrode 4 at alternatively stacked piezoelectric body layer 1 and internal electrode 2, internal electrode 2 is with an alternating floor ground and 4 conductings of each outer electrode.And, in the laminate type piezoelectric element of present embodiment 3, laminated body 30 the lamination up and down that drives laminate part 13 alternatively stacked piezoelectric body layer 1 and absentee layer 21 inertia protection portion 20 and constitute.

Particularly; in the laminate type piezoelectric element of present embodiment 3; constitute in laminated body 30 on the cross section vertical with stack direction; be made as A with the periphery of absentee layer 21 with to the beeline of the side of laminated body; in the time of will being made as B at the width of the inertia protection portion 20 on becoming the direction of this beeline, A/B is 0.01～0.08.That is, the width B of beeline A, inertia protection portion 20 is set in the invention of execution mode 3 as described above, can improve durability, even can access long-time use, the laminate type piezoelectric element that the reliability that characteristic does not also change is high.

If A/B is less than 0.01, then the zone of the bonding part between the piezoelectric body layer 1 of lamination becomes too small, in high voltage, long use continuously, owing to the stress that distortion is subjected to becomes bigger than the engaging force between the piezoelectrics, peel off easily in absentee layer 21 parts.

On the other hand; if A/B is greater than 0.08; the contraction difference when then burning till inertia protection portion 20 and driving laminate part 13 or the profile of contraction are different; generate big strain between the two; become bigger, under the serious situation, burn till the back and peel off than the engaging force between the electric conductor; or, peel off owing to use for a long time.

In the present invention, the value of A/B is preferably 0.02～0.07.More preferably 0.03～0.06.Thus, be difficult for peeling off of inertia protection portion 20 taken place, can improve durability.

In addition, preferably contain metal at absentee layer 21.Thus, can relax the stress that produces between the piezoelectric body layer 1, its result even under long-time situation about using, also can use for a long time, improves durability.The metallic element monomer in the periodic tables such as Ag, Cu, Ni, Pd can be as metal, also more than one alloy wherein can be.In addition, also can contain glass at absentee layer.

In addition, preferred absentee layer 21 is made of the material identical with internal electrode 2.Thus, the variation of burning till of inertia protection portion 20 and driving laminate part 13 is roughly the same, and the stress of Fa Shenging is suppressed between the two, can reduce and peel off, the piezoelectric element of the durability that is improved.

In addition, the thickness of preferred piezoelectric body layer 1 is more than the 50 μ m.By increasing thickness, can bear the stress of generation, can prevent to destroy.

In addition, preferred absentee layer 21 contains more than metal oxide as inorganic composition, nitride, carbide any one or two kinds of.By adding inorganic compositions to absentee layer 21, between piezoelectric body layer 1, produce the bridge formation of inorganic composition, to burning till or the grow of stress when using, therefore difficult peeling off improve durability.Also have,, can use PZT, Al as inorganic composition ₂O ₃, ZrO ₂, TiO ₂, SiO ₂, TiN, Si ₃N ₄, AlN, SiC and TiC etc.

In addition, preferred absentee layer 21 contains the above inorganic composition of 2wt%.Thus, the bridge formation between piezoelectric body layer 1 becomes fully, and the bond strength between the piezoelectric body layer 1 increases, and makes and peels off minimizing, improves durability.

Secondly, the manufacture method to the laminate type piezoelectric element of embodiments of the present invention 3 describes.

In the method, at first, the method identical with execution mode 1 made the ceramic base material multi-layer sheet as piezoelectric body layer 1.

Secondly, be suitable size with this substrate cut, be fixed on the frame in order to control A/B.

Secondly, in the metal dust of the internal electrode 2 that constitutes palladium one silver medal etc., add hybrid adhesive, plasticizer etc., make conductive paste, and by silk screen printing etc. with its thickness at described each printing 1～40 μ m above the substrate, use substrate and prepare to drive laminate part 13.

Secondly, by the absentee layer that contains palladium-Yin etc. equally of printing 1～40 μ m on substrate such as silk screen printing, use substrate and prepare inertia protection portion 20.When printing, consideration is burnt till contraction and is printed, and A/B is controlled to be the value of regulation.

And in order to control A/B, so that inertia protection portion 20 is positioned at the mode of the upper and lower that drives laminate part 13, the driving laminate part 13 usefulness substrates and the inertia protection portion 20 that are printed with conductive paste above lamination is a plurality of use substrate, and exerting pressure simultaneously is close to it.Like this by substrate is fixed on the frame, and makes inertia protection portion 20 simultaneously and drive laminate part 13 and be close to, and can control beeline A till the side of the outer thoughtful inertia protection portion 20 of absentee layer 21.

After this, be suitable size with substrate cut, under the temperature of regulation, take off adhesive treatment after, under 900～1200 ℃, burn till, make laminate type piezoelectric element.

Also have; laminate type piezoelectric element is not limited to above-mentioned manufacture method and the laminate type piezoelectric element made; so long as can control the method for the beeline A till the side of the outer thoughtful inertia protection portion 20 of absentee layer 21, just can form by any manufacture method.

Thereafter, alternatively form the internal electrode 2 that does not expose the internal electrode 2 that exposes the end and end in the side of laminate type piezoelectric element, the internal electrode 2 that does not expose in the end and piezoelectric body layer 1 part between the outer electrode 4 form groove 3, groove 3 in formation than the Young's modulus of piezoelectric body layer 1 low, insulators such as resin or rubber.At this, described groove 3 constitutes the conduction material of outer electrode 4 by cutter sweep etc. in the side that drives laminate part 13, absorbs the stress of the flexible generation of laminate type piezoelectric element fully, considers that from this point preferred low silver or the silver of Young's modulus is main component.

Secondly, the method by identical with execution mode 1 forms outer electrode 4.

Then, the driving laminate part 13 that forms outer electrode 4 be impregnated in silicone rubber solution, and, to the silicone rubber solution vacuum degassing, thus, to the groove 3 inner filled silicon rubbers that drive laminate part 13, propose to drive laminate part 13 from silicone rubber solution afterwards, on the side that drives laminate part 13, coating silicon rubber.Thereafter, make fill in the groove 3 and coating drive the described silicon rubber sclerosis of the side of laminate part 13 in column, thus, finish laminate type piezoelectric element of the present invention.

And, lead 6 is connected with outer electrode 4, apply the direct voltage of 0.1～3kV/mm by 6 pairs of pair of external electrodes 4 of this lead, and to driving laminate part 13 processing that polarizes, thus, finish the lamination-type piezo actuator that utilizes laminate type piezoelectric element of the present invention, if the voltage supply unit of lead 6 with the outside is connected, and apply voltage by lead and 4 pairs of internal electrodes 2 of outer electrode, then each piezoelectric body layer 1 displacement greatly owing to inverse piezoelectric effect, thus, for example can be used as, to the automotive fuel injection valve performance function of engine spray fueling.

Below, other the preferred mode of structure of the internal electrode of the laminate type piezoelectric element of execution mode 1～3, outer electrode is described.

＜internal electrode 〉

In the present invention, the metal constituent in the internal electrode 2, preferably with VIII family metal and/or Ib family metal as main component.Because these metal constituents have the height durability, therefore can also burn till firing temperature high piezoelectric body layer 1 and internal electrode 2 simultaneously.

In addition, metal constituent in the internal electrode 2 is made as M1 (weight %) at the content with VIII family metal, when the content of Ib family metal is made as M2 (weight %), is preferably and will satisfy the metal constituent of 0＜M1≤15,85≤M2＜100, M1+M2=100 as main component.This is because if VIII family metal surpasses 15 weight %, and then the resistivity of internal electrode 2 becomes big, and under the situation of Continuous Drive laminate type piezoelectric element, internal electrode 2 generates heat sometimes.In addition, in order to suppress Ib family metal in the internal electrode 2 to the migration of piezoelectric body layer 1, preferred VIII family metal is that 0.001 weight % is above but below 15 weight %.In addition, from improving the durability of laminate type piezoelectric element, be preferably more than the 0.1 weight %, below the 10 weight %.In addition, in needs heat conductivity excellence, under the situation of higher durability, more preferably more than the 0.5 weight %; 9.5 below the weight %.In addition, under the situation of pursuing higher durability, more preferably more than the 2 weight %, below the 8 weight %.

At this, it is because if Ib family metallized metal is lower than 85 weight % that Ib family metal is preferably more than the 85 weight %, and then the resistivity of internal electrode 2 becomes big, and under the situation of Continuous Drive laminate type piezoelectric element, internal electrode 2 generates heat sometimes.In addition, in order to suppress Ib family metal in the interior metal 12, preferably Ib family metal is made as more than the 85 weight %, below the 99.999 weight % to the migration of piezoelectric body layer 1.In addition, from improving the durability of laminate type piezoelectric element, preferably Ib family metal is made as more than the 90 weight %, below the 99.9 weight %.In addition, under the situation of the higher durability of needs, more preferably Ib family metal is made as more than the 90.5 weight %, below the 99.5 weight %.In addition, further pursuing under the situation of higher durability, further preferably Ib family metal is made as more than the 92 weight %, below the 98 weight %.

VIII family metal, the Ib family metal of representing the weight % of the metal ingredient in the above-mentioned internal electrode 2 can pass through EPMA, and (Electron Probe Micro Analysis: the electron detection microscopic analysis) analytical method such as method is specific.

In addition, the metal ingredient in internal electrode 2 of the present invention, preferred VIII family metal are more than at least a among NiPt, Pd, Rh, Ir, Ru, the Os, and Ib family metal is more than at least a among Cu, Ag, the Au.Because this be in recent years in the alloy powder synthetic technology metal of production excellence form.

In addition, the metal ingredient in the internal electrode 2, preferred VIII family metal are that Ib family metal is more than one among Ag, the Au more than at least a among Pt, the Pd.Thus, can form internal electrode 2 excellent heat resistance, that resistivity is little.

In addition, the metal ingredient in the internal electrode 2, preferred VIII family metal is Ni, Ib family metal is Cu.Thus, can form the internal electrode 2 of thermal endurance and conductivity of heat excellence.

In addition, preferably in internal electrode 2, add metal constituent and oxide, nitride or carbide.Thus, can strong bonded internal electrode 2 and piezoelectric body layer 1, improve the durability of laminate type piezoelectric element.

Preferred described oxide will be by PbZrO ₃-PbTiO ₃The perofskite type oxide of forming is as main component.Also have, the content of the oxide of interpolation etc. can recently be calculated by the area of the composition in the internal electrode on the section SEM picture of laminate type piezoelectric element.

In addition, the difference of composition before and after burning till in the preferred internal electrode 2 is below 5%.This is because if the difference of the composition in the internal electrode 2 before and after burn till surpasses 5%, and then the metal material in the internal electrode 2 becomes many to the migration of piezoelectric body layer 1, and internal electrode 2 possibly can't mate flexible that the driving of laminate type piezoelectric element causes.In addition, if the difference of forming before and after burning till in the electrode is below 5%, then can suppress the electrode hardening.

At this, the composition in the internal electrode 2 is meant that the element that constitutes internal electrode 2 by burning till, evaporates or spreads to piezoelectric body layer 1, and causes the rate of change of the composition variation of internal electrode 2.

In addition, in laminate type piezoelectric element of the present invention, preferred described internal electrode contains the space, and the area ratio of the entire profile area that the section of described internal electrode is occupied in the space is 5～70%.So, piezoelectrics restraining force to internal electrode by electrical field deformation the time is died down, can increase the displacement of piezoelectrics.In addition, because the stress of granting internal electrode is relaxed in the space, thereby, have the advantage that improves durability.In addition, the heat transfer in the element is passed, and internal electrode is overriding, if but internal electrode has the space, then relax the variations in temperature of the element internal that the rapid variations in temperature of element-external causes, therefore, can access the element of heat shock resistance.

In above execution mode 1～3, preferred internal electrode 2 has the space, and it is 5～70% than (below, be called voidage) that the space accounts for the long-pending area of the entire profile of section of internal electrode 2.

Like this, the internal electrode 2 that contains the space by use constitutes laminate type piezoelectric element, can access the high laminate type piezoelectric element of durability.If the voidage of internal electrode 2 is less than 5%, then to the restraining force grow of the displacement of piezoelectrics, the space exists and the effect that produces diminishes.In addition, if the voidage of internal electrode 2 greater than 70%, then the conductance of internal electrode 2 diminishes, and intensity decreases, so be not preferred.In order to improve the durability of element, the voidage of internal electrode 2 more preferably 7～70% further preferably is made as 10～60% by the voidage with internal electrode 2, guarantees high displacement and realizes high-durability.

At this, as mentioned above, the voidage of internal electrode 2 is meant that the space accounts for the long-pending area ratio of the entire profile of the section of internal electrode 2, but specifically, mode is obtained as described below.

That is, the mode parallel with stack direction cut off laminate type piezoelectric element, and sees by for example microscope, obtains and examines the space occupied area that the entire profile is long-pending and the space is occupied that exposes at an internal electrode 2 of its vertical section.Then, according to this area than the voidage of calculating internal electrode 2 ((space occupied area/the entire profile long-pending) * 100).

In addition, the internal electrode 2 that contains the space can be made by the following stated mode.

At first,, use the different two or more material of fusing point, can after burning till, producing the space on the internal electrode 2 as the metal dust that constitutes internal electrode 2.At this moment, according to purpose, also can use alloy as metal material.

Also have, in the metal dust that constitutes internal electrode 2, more than the fusing point of the minimum metal of fusing point, and the highest following temperature lower calcination of fusing point of fusing point.If at such temperature lower calcination, then move in the gap of melt metal not by capillarity at melt metal or alloy on this fusing point, form the space originally where in melt metal.In the method, the mixed proportion of the two or more metal dust by regulate constituting internal electrode 2, and temperature can be set the voidage of internal electrode 2 with the ratio of hope.

Also have, the space of internal electrode 2 also can utilize the gap that produces after minim gap that is producing between the metal dust or the binding agent igloss that is contained in conductive paste etc. when regulating the conductive paste that uses in order to form internal electrode 2.

In addition, can also be by adding the material of formation internal electrode 2 and the material of wetability difference with conductive paste to internal electrode, or, in internal electrode 2, form the gap being printed with internal electrode with the material of the face coat formation internal electrode 2 of the electric conductor substrate of conductive paste and the material of wetability difference.At this,, can enumerate for example BN as the material that constitutes internal electrode 2 and the material of wetability difference.

＜piezoelectric body layer 1 〉

In the present invention, preferred piezoelectric body layer 1 with perofskite type oxide as main component.This be because if by will be for example barium titanate (BaTiO3) form as the Ca-Ti ore type piezoceramic material of representative etc., then because the piezoelectric strain constant d of its piezoelectric property of expression ₃₃Greatly, therefore, displacement can be increased, in addition, piezoelectric body layer 1 and internal electrode 2 can also be burnt till simultaneously.As the piezoelectric body layer 1 shown in above-mentioned, preferably by piezoelectric strain constant d ₃₃The perofskite type oxide that bigger PbZrO3-PbTiO3 constitutes is as main component.

In addition, preferred firing temperature is more than 900 ℃ but below 1000 ℃.This is because under firing temperature is situation below 900 ℃, because firing temperature is low, burns till insufficiently, is difficult to make fine and close piezoelectric body layer 1.In addition, this is because if firing temperature surpasses 1000 ℃, and then the stress that departs from generation of the contraction of the contraction of internal electrode 2 and piezoelectric body layer 1 becomes big when burning till, and produces the crack during Continuous Drive laminate type piezoelectric element.

Connection between＜internal electrode and the outer electrode and insulation 〉

In addition, be preferably, the end is exposed the internal electrode 2 that does not expose in the internal electrode 2 and the end of the side of laminate type piezoelectric element of the present invention and is alternatively constituted, internal electrode 2 that does not expose in described end and the piezoelectrics between the outer electrode 4 partly form groove, in this groove, form the Young's modulus insulator lower than piezoelectric body layer 1.Thus, in such laminate type piezoelectric element, can relax the stress that produces by the displacement in driving, therefore, even Continuous Drive also can suppress the heating of internal electrode 2.

＜outer electrode 4 〉

In the present invention, outer electrode 4, preferably outer electrode 4 is made of the porous matter electric conductor that is the three dimensional network ocular structure shown in Fig. 4 A, B.If outer electrode 4 is not made of the porous matter electric conductor that is the three dimensional network ocular structure, then because outer electrode 4 does not have flexible, therefore, can not cooperate the flexible of lamination-type piezo actuator, so the contact condition of poor of broken string or the outer electrode 4 and the internal electrode 2 of outer electrode 4 takes place sometimes.At this, the three dimensional network ocular structure is meant owing to constitute conduction material powder and glass powder burn-back under lower temperature of outer electrode 4, therefore, incomplete sintering, state with the binding of the degree that has the space exists, three-dimensional link, engage the conduction material powder that constitutes outer electrode 4 and the state of glass powder, rather than externally there is the state in spherical space in electrode 4.

Perhaps, the voidage in the preferred outer electrode 4 is 30～70 volume %.At this, voidage is meant externally shared ratio in the electrode 4 of space 4a.If the voidage in the outer electrode 4 is less than 30 volume %, then outer electrode 4 can not bear the stress by the flexible generation of lamination-type piezo actuator, has the possibility of outer electrode 4 broken strings.In addition, if the voidage in the outer electrode 4 surpasses 70 volume %, then the resistance value of outer electrode 4 becomes big, and therefore, when flowing through big electric current, outer electrode 4 causes local pyrexia, may cause broken string.

In addition, the piezoelectric body layer 1 of preferred externally electrode 4 is surveyed skin section, is formed with the glass enriched layer.This is because if there is not the glass enriched layer, then with outer electrode 4 in glass ingredient be difficult to engage, therefore, outer electrode 4 is difficult for and piezoelectric body layer 1 firm engagement.

In addition, preferably constitute the glass of outer electrode 4 softening point (℃) for the fusing point of the conduction material that constitutes internal electrode 2 (℃) below 4/5.This be because if constitute the softening point of the glass of outer electrode 4 surpass the conduction material that constitutes internal electrode 2 fusing point 4/5, then constitute the softening point of glass of outer electrode 4 and the temperature that the fusing point that constitutes the conduction material of internal electrode 2 becomes same degree, therefore, the temperature of burn-back outer electrode 4 is inevitable near the fusing point that constitutes internal electrode 2, so when burn-back outer electrode 4, the conduction material cohesion of internal electrode 2 and outer electrode 4 hinders diffusion bond, maybe the burn-back temperature can not be set at the softening required sufficient temperature of glass ingredient of outer electrode 4, so the sufficient joint strength that has of the glass that can not obtain softening sometimes.In addition, the piezoelectric body layer 1 of preferred externally electrode 4 is surveyed skin section and is formed the glass enriched layer.This is because if there is not the glass enriched layer, then is difficult to engage with the glass ingredient of outer electrode 4, and therefore, outer electrode 4 is difficult for firm engagement with piezoelectric body layer 1 sometimes.

In addition, the glass that preferably constitutes outer electrode 4 is noncrystalline.This is that outer electrode 4 can not absorb the flexible stress that causes by the lamination-type piezo actuator, therefore, produces the crack sometimes because in the glass of crystalline.

In addition, the thickness of preferred outer electrode 4 is than the thin thickness of piezoelectric body layer 1.This is because if the thickness of outer electrode 4 is thicker than the thickness of piezoelectric body layer 1, and then because the intensity of outer electrode 4 increases, therefore, when laminated body was flexible, the load at the junction surface of outer electrode 4 and internal electrode 2 increased, and the contact condition of poor takes place sometimes.

In addition, also externally the outside of electrode 4 form the conductivity auxiliary part that constitutes by the conductive adhesive that is embedded with screening or mesh-shape metallic plate.By so externally outside of electrode 4 the conductivity auxiliary part is set, even at the electric current that has high input to actuator, under the situation of high-speed driving, electric current also can flow through the conductivity auxiliary part, therefore, can reduce the electric current that flows through outer electrode 4.Thus, the situation that outer electrode 4 breaks owing to local pyrexia can be prevented, durability can be increased substantially.In addition, owing in conductive adhesive, be embedded with screening or mesh-shape metallic plate, therefore, can prevent to produce the crack on the described conductive adhesive.

Screening is meant the structure of braided metal line, and the mesh-shape metallic plate is meant formation hole on metallic plate and forms cancellous structure.

In addition, the conductive adhesive that preferably constitutes described conductivity auxiliary part is made of the polyimide resin of dispersed electro-conductive particle.

In addition, preferably this electroconductive particle is a silver powder.This is because by use the low silver powder of resistance value on electroconductive particle, be easy to suppress the local pyrexia of conductive adhesive.In addition, because the silver powder that resistance value is low is dispersed in the high polyimide resin of thermal endurance, even at high temperature use, it is low and keep the conductivity auxiliary part of high bond strength also can to form resistance value.In addition, preferred described electroconductive particle is aspheric particles such as sheet or needle-like.This is because by electroconductive particle being formed nonspherical particles such as sheet or needle-like, and the firmly polymerization between this electroconductive particle can further improve the shear strength of this conductive adhesive.

In addition, laminate type piezoelectric element of the present invention, preferred veneer or lamination number are 1 or more than it.Thus, to be converted to voltage to the element applied pressure, and, by element is applied voltage, can make the element displacement, therefore, even in element drives, be applied in unforeseeable stress, also dispersive stress changing voltage, thus, stress can be relaxed, therefore, the lamination-type piezo actuator of the height reliability of excellent in te pins of durability can be provided.

Laminate type piezoelectric element of the present invention is not limited thereto, and only otherwise break away from the scope of aim of the present invention, just can carry out various changes.

In addition, in above-mentioned, the example that the side in the laminated body subtend is formed outer electrode 4 is illustrated, but in the present invention, also can for example form pair of external electrodes on the side that is provided with.

Also have, in the present invention, laminated body may not be four side column shapes, also can be various forms such as cylinder, polygon post.

(execution mode 4)

Fig. 6 represents injection apparatus of the present invention, is provided with spray-hole 33 at an end of accepting container 31, in accepting container 31, contains the needle-valve 35 that can open and close spray-hole 33 in addition.

Can be provided with fuel passage 37 communicatively at spray-hole 33, this fuel passage 37 links with the fuel supply source of outside plate, usually with certain high pressure to fuel passage 37 fuelings.Thereby, forming under the situation of needle-valve 35 open spray-holes 33, the fuel that supplies to fuel passage 37 sprays in the not shown fuel chambers of internal combustion engine with certain high pressure.

In addition, it is big that the diameter of the upper end of needle-valve 35 becomes, and is formed with cylinder 39 that is formed on accepting container 31 and the piston 41 that can slide.And, in accepting container 31, contain above-mentioned piezo actuator 43.

In such injection apparatus, if piezo actuator 43 is applied in voltage and extends, then piston 41 is urged, and needle-valve 35 stops up spray-hole 33, stops the supply of fuel.In addition, if stop to apply voltage, then piezo actuator 43 shrinks, disk spring 45 pushing piston 41, and spray-hole 33 is communicated with fuel passage 37, carries out the injection of fuel.

In addition, the present invention relates to laminate type piezoelectric element and injection apparatus, but be not limited to the foregoing description, for example, except carrying fuel injection device in automobile engine, liquid injection apparatus such as ink-jet, the driving element of precision positioning device such as Optical devices or the anti-locking apparatus of vibration etc., perhaps carry at combustion pressure sensor, seismological sensor, acceleration transducer, load sensor, ultrasound sensors, voltage sensitive sensor, the sensor element of yaw rate sensor etc., and use piezoelectric gyroscope, Piezoelectric switches, piezoelectric transformer, outside the circuit element of piezoelectricity circuit breaker etc., so long as use the element of piezoelectric property, just can implement.

(embodiment)

As embodiment 1～3, made lamination-type piezo actuator of the present invention by the mode of the following stated.

At first, manufacturing has mixed lead zirconate titanate (PbZrO ₃-PbTiO ₃) as the calcined powder of the piezoelectric ceramic of main component, binding agent, and the raw material of plasticizer, as thickness the ceramic base material multi-layer sheet of the piezoelectric body layer 1 of 150 μ m with the scraping blade manufactured.

On the multiple-plate single face of ceramic base material, 300 conductive pastes of lamination form the sheet of the thickness of 3 μ m by silk screen print method, burn till under 1000 ℃, and described conductive paste is the palladium-silver that forms with ratio of components arbitrarily that is added with binding agent.

Secondly, having formed the degree of depth in the end of the internal electrode of the side of laminated body in the mode of an alternating floor by cutter sweep is 50 μ m, and width is the groove of 50 μ m.

Secondly, total weight 100 mass parts of adding relative silver powder and glass powder in mixture are the binding agent of 8 mass parts, fully mix and make silver-colored glass conductive paste, this mixture comprises, average grain diameter is the silver powder 90 volume % of the sheet of 2 μ m, remainder with average grain diameter be 2 μ m silicon as main component, softening point is amorphous glass powder 10 volume % of 640 ℃.On demoulding type film, form the silver-colored glass conductive paste of making like this by silk screen printing, after the drying, peel off, obtain the sheet of silver-colored glass conductive paste from demoulding type film.Measure the original density of this sheet through Archimedes's method, be 6.5g/cm ³

Secondly, the sheet of described silver-colored glass conductive paste is replicated in the outer electrode 4 of laminated body,, has formed the outer electrode 4 that constitutes by the porous matter electric conductor that is the three dimensional network ocular structure 650 ℃ of following burn-backs 30 minutes.Also have, the voidage of the outer electrode 4 of this moment is 40% through the result of the section photograph of graphical analysis device mensuration outer electrode 4.

Afterwards, lead is connected outer electrode 4, apply to the outer electrode 4 of positive pole and negative pole by lead 15 minutes 3kV/mm DC electric field and the lamination-type piezo actuator that uses laminate type piezoelectric element has as shown in Figure 1 been made in the processing that polarizes.

(embodiment 1)

On the basis of above-mentioned manufacture method, at the resistance value of suppression element resistance or the inductive loss of piezoelectric body layer 1 (tan δ) and in the lamination-type piezo actuator of making of the present invention, measure rate of change, and the rate of change of component temperature of gauge rate of change, the component resistance of rate of change, the piezoelectrics of the element displacement before and after the Continuous Drive of lamination-type piezo actuator, verified they and the long-term relation that drives the degree of the deterioration that the lamination-type piezo actuator causes.

At this, the degree of deterioration is meant behind the lamination-type piezo actuator that drives arbitrary number of times, the displacement of measuring element (the element displacement after the Continuous Drive), in addition, measure will be above-mentioned the lamination-type piezo actuator drive under the condition of displacement (the element displacement after long-term the driving) of the element behind the number of times of regulation the ratio of the element displacement quantitative changeization after the described relatively Continuous Drive of element displacement after this long-term driving.Thus, can make Continuous Drive arbitrarily the lamination-type piezo actuator of the number of times number of times that drives regulation in addition confirm the state of the deterioration that causes thus.

In addition, as a comparative example, made the rate of change of the element displacement before and after the Continuous Drive of above-mentioned lamination-type piezo actuator or surpassed the sample that 5% scope forms at the rate of change of component resistance.

Through the lamination-type piezo actuator that obtains as described above being applied the result of the direct voltage of 170V, in all lamination-type piezo actuators, obtain the displacement of 45 μ m on stack direction.In addition, carried out following test, that is: to this lamination-type piezo actuator at room temperature with the frequency of 150Hz apply 0～+ alternating voltage of 170V, Continuous Drive to 1 * 10 ⁹Inferior, even, be driven into 1 * 10 for a long time ¹⁰Its result is as shown in table 1.In order to measure the gauge rate of change of piezoelectrics, use SEM measure the laminate type piezoelectric element before driving the side any 1 place piezoelectrics gauge and calculate mean value, after the driving, measure the gauge at same place and calculate mean value, calculate the rate of change of the gauge of the piezoelectrics before and after driving.

Table 1-1

No	With silver 100% resistance be made as 1 formative internal electrode resistance	The inductive loss tan δ (%) of piezoelectrics	Displacement under the A-stage (μ m)=A	After the Continuous Drive (1 * 10 9Inferior) rate of change (%) of component temperature
					1	2	0.5	45.0	0.0
2	3	0.5	45.0	0.2
					3	3.5	0.5	45.0	0.4
4	4	0.5	45.0	0.6
					5	5	0.5	45.0	0.8
6	8	0.5	45.0	1.2
					7	10	0.5	45.0	2.6
8	5	1.0	45.0	4.5
					*9	5	1.5	45.0	6.2

Table 1-2

No	After the Continuous Drive (1 * 10 9Inferior) rate of change (%) of the gauge of piezoelectrics	After the Continuous Drive (1 * 10 9Inferior) rate of change (%) of component resistance	After the Continuous Drive (1 * 10 9Inferior) maximum displacement (μ m)=B
				1	0.0	0.0	45.0
2	0.2	0.2	44.9
				3	0.4	0.4	44.8
4	0.6	0.7	44.7
				5	0.8	0.9	44.6
6	1.2	1.3	44.4
				7	2.6	2.9	43.7
8	5.0	5.0	42.8
				*9	6.4	6.9	41.9

Table 1-3

No	The displacement rate of change (%) of relative A-stage after the Continuous Drive=| (A-B)/A * 100|	The long-term back (1 * 10 that drives 10Inferior) displacement (μ m)=C	The degree of deterioration (%)=| (B-C)/B * 100|
				1	0.0	45.0	0.00
2	0.2	44.9	0.00
				3	0.4	44.7	0.22
4	0.7	44.6	0.22
				5	0.9	44.4	0.45
6	1.3	44.1	0.68
				7	2.9	43.2	1.14
8	5.0	41.9	2.10
				*9	6.9	38.5	8.11

In the table, the sample of additional * is a comparative example.

As known from Table 1, comparative example be specimen coding 9 because the rate of change of the element displacement before and after the Continuous Drive is bigger than 5%, therefore, if with lamination-type piezo actuator Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, then compare Continuous Drive to 1 * 10 ⁹Displacement after inferior is driven into 1 * 10 for a long time ¹⁰Element displacement after inferior significantly reduces, and therefore, the degree of deterioration increases, and it is difficult that the Continuous Drive of lamination-type piezo actuator becomes.

In addition, because the rate of change of the component resistance before and after the Continuous Drive is bigger than 5%, therefore, if with lamination-type piezo actuator Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, then compare Continuous Drive 1 * 10 ⁹Element displacement after inferior drives 1 * 10 for a long time ¹⁰Inferior element displacement significantly reduces, and therefore, increases the degree of deterioration, and it is difficult that the Continuous Drive of lamination-type piezo actuator becomes.

In addition, because the rate of change of the piezoelectrics size before and after the Continuous Drive is bigger than 5%, therefore, if with lamination-type piezo actuator Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, then compare Continuous Drive 1 * 10 ⁹Element displacement after inferior drives 1 * 10 for a long time ¹⁰Inferior element displacement significantly reduces, and therefore, increases the degree of deterioration, and it is difficult that the Continuous Drive of lamination-type piezo actuator becomes.

To this, in the specimen coding 1～8 of embodiments of the invention 1, because the rate of change of the element displacement in the Continuous Drive is at the 5% lamination-type piezo actuator that forms in interior scope, therefore, even Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, the element displacement does not significantly reduce yet, and has as the required effective displacement of lamination-type piezo actuator, in addition, can make and not produce thermal runaway or mistake operation lamination-type piezo actuator that do not take place, excellent in te pins of durability.

Equally, in the specimen coding 1～8 of embodiments of the invention 1, because the rate of change of the component resistance in the Continuous Drive is in 5%, therefore, even Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, the element displacement does not significantly reduce yet, and has as the required effective displacement of lamination-type piezo actuator, in addition, can make and not produce thermal runaway or mistake operation lamination-type piezo actuator that do not take place, excellent in te pins of durability.

Equally, in the specimen coding 1～8 of embodiments of the invention 1, because the rate of change of the piezoelectrics size in the Continuous Drive is in 5%, therefore, even Continuous Drive to 1 * 10 ⁹After inferior, be driven into 1 * 10 for a long time ¹⁰Inferior, the element displacement does not significantly reduce yet, and has as the required effective displacement of lamination-type piezo actuator, in addition, can make and not produce thermal runaway or mistake operation lamination-type piezo actuator that do not take place, excellent in te pins of durability.

(embodiment 2)

On the basis of above-mentioned manufacture method, at the resistance value of suppression element resistance or the inductive loss of piezoelectric body layer 1 (tan δ) and in the lamination-type piezo actuator of making of the present invention, measure rate of change, and the rate of change of component temperature of rate of change, the component resistance of the element displacement in the Continuous Drive of lamination-type piezo actuator, verified they and the long-term relation that drives the degree of the deterioration that the lamination-type piezo actuator causes.

At this, the degree of deterioration is meant that mensuration is with the maximum element displacement (the maximum element displacement in the Continuous Drive) in the arbitrary number of times driving, in addition, measure will be above-mentioned the lamination-type piezo actuator drive under the condition of displacement (the element displacement after long-term the driving) of the element behind the number of times of regulation the ratio of the maximum element displacement variation in the described relatively Continuous Drive of the element displacement after this Continuous Drive.Thus, the state of the deterioration that causes of the number of times stipulated of the lamination-type piezo actuator in can confirming to drive owing to drive with arbitrary number of times.

In addition, as a comparative example, made the rate of change of the element displacement in the Continuous Drive of above-mentioned lamination-type piezo actuator or surpassed the sample that 5% scope forms at the rate of change of component resistance.

The lamination-type piezo actuator that obtains is as described above applied the result of the direct voltage of 170V, in all lamination-type piezo actuators, can access the displacement of 45 μ m on stack direction.In addition, carried out following driving test, that is: to this lamination-type piezo actuator at room temperature with the frequency of 150Hz apply 0～+ alternating voltage of 170V, Continuous Drive to 1 * 10 ⁹Inferior.Its result is as shown in table 2.

Table 2-1

No	With silver 100% resistance be made as 1 formative internal electrode resistance	The inductive loss tan δ (%) of piezoelectrics	Displacement under the A-stage (μ m)=A
				1	2	0.5	45.0
2	3	0.5	45.0
				3	4	0.5	45.0
4	5	0.5	45.0
				5	8	0.5	45.0
6	10	0.5	45.0
				7	5	1.5	45.0
*8	8	1.5	45.0
				*9	10	2.5	45.0

Table 2-2

No.	In the Continuous Drive (1 * 10 8Inferior) the rate of change (%) of component temperature	In the Continuous Drive (1 * 10 8Inferior) the maximum rate of change (%) of component resistance	In the Continuous Drive (1 * 10 8Inferior) maximum addendum modification (μ m)=B
				1	0.0	0.0	45.0
2	0.2	0.2	44.9
				3	0.4	0.4	44.8
4	0.6	0.7	44.7
				5	0.8	0.9	44.6
6	1.8	2.0	44.1
				7	4.5	5.0	42.8
*8	7.0	7.8	41.5
				*9	5.0	5.6	47.5

Table 2-3

No.	The maximum rate of change (%) of the displacement of relative A-stage in the Continuous Drive=| (A-B)/A * 100|	After the Continuous Drive (1 * 10 9Inferior) displacement (μ m)=C	The degree of deterioration (%)=| (B-C)/B * 100|
				1	0	45.0	0.00
2	0.2	44.9	0.00
				3	0.4	44.7	0.22
4	0.7	44.6	0.22
				5	0.9	44.4	0.45
6	2.0	43.7	0.91
				7	5.0	41.9	1.99
*8	7.8	38.0	8.43
				*9	5.6	Thermal runaway takes place	-

The specimen coding of additional * is the sample outside the request scope of the present invention.

As known from Table 2, comparative example be specimen coding 8 and 9 because the maximum rate of change of element displacement in the Continuous Drive is bigger than 5%, therefore, with lamination-type piezo actuator Continuous Drive to 1 * 10 ⁹Under the inferior condition, compare Continuous Drive to 1 * 10 ⁸Inferior maximum element displacement, Continuous Drive to 1 * 10 ⁹Element displacement after inferior significantly reduces, and therefore, increases the degree of deterioration, and in addition, specimen coding 9 destroys owing to thermal runaway causes the element displacement, the difficulty so the Continuous Drive of lamination-type piezo actuator becomes.

Because the maximum rate of change of the component resistance before and after the Continuous Drive is bigger than 5%, therefore, with lamination-type piezo actuator Continuous Drive to 1 * 10 ⁹Under the inferior condition, compare Continuous Drive to 1 * 10 ⁸Inferior maximum element displacement, Continuous Drive to 1 * 10 ⁹Element displacement after inferior significantly reduces, and therefore, increases the degree of deterioration, and it is difficult that the Continuous Drive of lamination-type piezo actuator becomes.

To this, in the specimen coding 1～7 of embodiments of the invention 2, because the maximum rate of change of the element displacement in the Continuous Drive is at the 5% lamination-type piezo actuator that forms in interior scope, therefore, even in Continuous Drive to 1 * 10 ⁹After inferior, the element displacement does not significantly reduce yet, and has as the required effective displacement of lamination-type piezo actuator, in addition, can make and not produce thermal runaway or mistake operation lamination-type piezo actuator that do not take place, excellent in te pins of durability.

Equally, in the specimen coding 1～7 of embodiment 2, because the rate of change of the component resistance before and after the Continuous Drive is in 5%, therefore, even in Continuous Drive to 1 * 10 ⁹After inferior, have, in addition, can make and not produce thermal runaway or mistake operation lamination-type piezo actuator that do not take place, excellent in te pins of durability as the required effective displacement of lamination-type piezo actuator.

(embodiment 3)

In above-mentioned manufacture method, in lamination-type piezo actuator with internal electrode 2 of forming formation with various electrode materials, measure the maximum rate of change of the element displacement in the Continuous Drive of lamination-type piezo actuator, the electrode material of having verified internal electrode 2 is formed and the relation of the degree of the deterioration that the Continuous Drive of lamination-type piezo actuator causes.

The lamination-type piezo actuator that obtains is as described above applied the result of the direct voltage of 170V, in all lamination-type piezo actuators, can access the displacement of 45 μ m on stack direction.In addition, carried out following driving test, that is: to this lamination-type piezo actuator at room temperature with the frequency of 150Hz apply 0～+ alternating voltage of 170V, Continuous Drive to 1 * 10 ⁹Inferior.Its result is as shown in table 2.

Table 3-1

No	Pd in the internal electrode metal (weight %)	Ag in the internal electrode metal (weight %)	Cu in the internal electrode metal (weight %)	Ni in the internal electrode metal (weight %)
					1	0	100	0	0
2	0.001	99.999	0	0
					3	0.01	99.99	0	0
4	0.1	99.9	0	0
					5	0.5	99.5	0	0
6	1	99	0	0
					7	2	98	0	0
8	4	95	1	0
					9	5	95	0	0
10	8	92	0	0
					11	9	91	0	0
12	9.5	90.5	0	0
					13	10	90	0	0
14	15	85	0	0
					15	0	0	100	0
16	0	0	99.9	0.1
					17	0	0	0	100
18	20	80	0	0
					19	30	70	0	0

Table 3-2

No.	The displacement rate of change (%) of relative A-stage after the Continuous Drive	The degree of deterioration (%)
			1	Damaged owing to move	-
2	0.7	0.22
			3	0.7	0.22
4	0.4	0.22
			5	0.2	0.00
6	0.2	0.00
			7	0	0.00
8	0	0.00
			9	0	0.00
10	0	0.00
			11	0.2	0.00
12	0.2	0.00
			13	0.4	0.22
14	0.7	0.22
			15	0.2	0.00
16	0	0.00
			17	0.4	0.22
18	0.9	0.45
			19	0.9	0.45

As known from Table 3, therefore silver-migration, takes place owing to the silver with 100% forms internal electrode 2 in specimen coding 1, and the destruction of lamination-type piezo actuator is taken place, and therefore, it is difficult that Continuous Drive becomes.

In addition, in the metal constituent of specimen coding 18,19 in internal electrode 2, the content of VIII family metal surpasses 15 weight %, in addition, the content of Ib family metal is lower than 85 weight %, therefore, the deterioration that Continuous Drive causes increases, so reduce the durability of lamination-type piezo actuator.

To this, in the specimen coding 2～17 of embodiments of the invention 3, in the metal constituent in internal electrode 2, the content of VIII family metal is made as M1 (weight %), when the content of Ib family metal is made as M2 (weight %), the metal constituent that preferably will satisfy 0＜M1≤15,85≤M2＜100, M1+M2=100 is as main component, therefore, can reduce the resistivity of internal electrode 2, even Continuous Drive also can suppress the heating of generation in the internal electrode 2, therefore, can make the stable lamination-type piezo actuator of element displacement.

Also have, the invention is not restricted to the foregoing description, it is also harmless to carry out various changes in the scope that does not break away from aim of the present invention.

(embodiment 4)

As embodiment 4, made lamination-type piezo actuator of the present invention by the mode of the following stated.

At first, made the column laminated body.Piezoelectrics are the lead zirconate titanate (PbZrO of 150 μ m by thickness ₃-PbTiO ₃) form, to this, the thickness of internal electrode forms 3 μ m, and each lamination number form of piezoelectrics and internal electrode is become 300 layers.Internal electrode has used metal as shown in table 4 (for example, 90Ag-10Pd) and the mixture of powder such as pottery.As ceramic powders, preferably use PZT, ZrO ₂, TiO ₂, PZT and ZrO ₂Mixture, PZT and TiO ₃Mixture etc.At this, the material shown in the table 4-3 is used in the ratio shown in the table.In addition, in the particle diameter of powder such as pottery, it is 3 particle that the particle that constitutes the following post of 1.5 μ m has used aspect ratio.Thereafter, laminated body after 400～700 ℃ of degreasings, 850 ℃ down keep 20 minutes after, carry out 1000 ℃ and keep and obtain sintered body.Metal constituent at internal electrode is under the situation of Ni, laminated body after 400～700 ℃ of following degreasings, 1050 ℃ down keep 20 minutes after, carry out 1200 ℃ and keep and obtain sintered body.

Thereafter, by cutter sweep, from the end of the internal electrode of the side of column laminated body, having formed the degree of depth in the mode of an alternating floor is that 50 μ m, width are the groove of 50 μ m.

Secondly, total weight 100 mass parts of adding relative silver powder and glass powder in mixture are the binding agent of 8 mass parts, fully mix and make silver-colored glass conductive paste, this mixture comprises, average grain diameter is the silver powder 90 volume % of the sheet of 2 μ m, remainder with average grain diameter be 2 μ m silicon as main component, softening point is amorphous glass powder 10 volume % of 640 ℃.On demoulding type film, form the silver-colored glass conductive paste of making like this by silk screen printing, after the drying, peel off, obtain the sheet of silver-colored glass conductive paste from demoulding type film.Measure the original density of this sheet through Archimedes's method, be 6.5g/cm ³

Secondly, the sheet of described silver-colored glass conductive paste is replicated in the external electric pole-face of column laminated body,, has formed the outer electrode that constitutes by the porous matter electric conductor that is the three dimensional network ocular structure 650 ℃ of following burn-backs 30 minutes.Also have, the voidage of the outer electrode of this moment is 40% through the result of the section photograph of graphical analysis device mensuration outer electrode 4.

Afterwards, lead is connected outer electrode, apply to the outer electrode of positive pole and negative pole by lead 15 minutes 3kV/mm DC electric field and the lamination-type piezo actuator that uses laminate type piezoelectric element has as shown in Figure 1 been made in the processing that polarizes.

Apply the direct voltage of 170V to the lamination-type piezo actuator that constitutes by resulting laminate type piezoelectric element, measure the displacement of sample respectively, calculate its deviation, expression in table 4.In addition, at room temperature with the frequency of 150Hz to the lamination-type piezo actuator that constitutes by this laminate type piezoelectric element apply 0～+ alternating voltage of 170V, and test.

To reaching 1 * 10 by driving number of times ⁹The lamination-type piezo actuator that inferior laminate type piezoelectric element constitutes applies the direct voltage of 170V, measures the displacement of sample respectively, calculates the variation of the displacement that drives the test front and back.In calculating, will drive displacement before and after the test as molecule, the displacement after driving as denominator, and be multiply by 100 usefulness % to this and represents.

Also have, the inleakage electrode also links diameter, the number of the post between the piezoelectrics, measures by the following stated.

To the bonding part is the ratio of the post more than 50% of maximum gauge, measure the length of 1mm near the internal electrode 2 of as shown in Figure 2 laminate type piezoelectric element the section photograph, to each post 18, measure the diameter B of the bonding part 22 of maximum gauge A, post 18 and piezoelectric body layer 1, calculate (B/A) * 100, obtain the ratio of the maximum gauge A of post 18 and post 18 and the diameter B of the bonding part 22 of piezoelectric body layer 1.Then, calculating in its value is the percentage of the quantity of occupying mensuration more than 50%.10 places are calculated like this, and averaged as numeric representation.In addition, the maximum gauge of post is by carrying out with above-mentioned same mensuration.In addition, being determined at 10 places carries out.

The thermal expansion differences of the above result and material, piezoelectrics and the post of internal electrode etc. are as shown in table 4.

Table 4-1

No	Post	The bonding part is the ratio of the post more than 50% of maximum gauge	The mean value of the minimum diameter of post	The number of the post in the 1mm
						-	％	μm	Individual
1	Have	20	1	65
					2	Have	30	1	77
3	Have	50	1	83
					4	Have	70	1	76
5	Have	90	1	68
					6	Have	50	0.1	95
7	Have	50	0.2	84
					8	Have	50	0.5	63
9	Have	50	1	61
					10	Have	50	3	50
11	Have	50	5	34
					12	Have	50	2	5
13	Have	50	2	11
					14	Have	50	2	54
15	Have	50	2	99
					16	Have	50	2	148
17	Have	50	1	84
					18	Have	50	1	90
19	Have	50	1	79
					20	Have	50	1	76
21	Have	50	1	86
					22	Have	50	1	83
23	Have	50	1	76
					24	Have	50	1	89
25	Have	50	1	83
					26	Do not have	-	-	-

Table 4-2

No	The thermal expansion difference of piezoelectrics and post * 10 -5/℃	The material of piezoelectrics and post	The material of internal electrode
				1	0	Identical	90Ag-10Pd
2	0	Identical	90Ag-10Pd
				3	0	Identical	90Ag-10Pd
4	0	Identical	90Ag-10Pd
				5	0	Identical	90Ag-10Pd
6	0	Identical	90Ag-10Pd
				7	0	Identical	90Ag-10Pd
8	0	Identical	90Ag-10Pd
				9	0	Identical	90Ag-10Pd
10	0	Identical	90Ag-10Pd
				11	0	Identical	90Ag-10Pd
12	0	Identical	90Ag-10Pd
				13	0	Identical	90Ag-10Pd
14	0	Identical	90Ag-10Pd
				15	0	Identical	90Ag-10Pd
16	0	Identical	90Ag-10Pd
				17	2	Different	90Ag-10Pd
18	5	Different	90Ag-10Pd
				19	6	Different	90Ag-10Pd
20	0	Identical	85Ag-15Pd
				21	0	Identical	95Ag-5Pd
22	0	Identical	99Ag-1Pd
				23	0	Identical	99.9Ag-0.1Pd
24	0	Identical	100Cu
				25	0	Identical	100Ni
26	-	-	70Ag-30Pd

Table 4-3

No	The material of post	Addition (weight %)
			1	PZT	20
2	PZT	23
			3	PZT	24
4	PZT	22
			5	PZT	20
6	PZT	27
			7	PZT	24
8	PZT	19
			9	PZT	19
10	PZT	16
			11	PZT	12
12	PZT	5
			13	PZT	6
14	PZT	17
			15	PZT	28
16	PZT	40
			17	PZT 20％+ZrO 2 80％	24
18	PZT 50％+ZrO 2 50％	26
			19	PZT 50％+TiO 2 50％	23
20	PZT	22
			21	PZT	25
22	PZT	24
			23	PZT	22
24	PZT	26
			25	PZT	24
26	-	-

Table 4-4

No	The deviation % of displacement	The rate of change % of the displacement after the continuous long duration test
			1	10	5
2	8	4
			3	5	2.5
4	5	1
			5	4	0.5
6	8	4
			7	7	4
8	6	3
			9	5.5	2.5
10	4	1
			11	3	0.5
12	7	4
			13	6	3
14	4	2
			15	3	0.5
16	2	0.5
			17	3	0.5
18	3	0.5
			19	3	0.5
20	3	1
			21	3	0.5
22	3	0.5
			23	3	0.5
24	3	0.5
			25	3	0.5
2 6	20	10

The inleakage electrode is set, and the deviation of displacement at initial stage of sample No.1～25 of embodiments of the invention 4 that links the post of the piezoelectrics clip the internal electrode subtend is below 10%, it is little to compare comparative example (No.26).In addition we know, the variation of the displacement after the long duration test also is very little below 5% continuously, compares comparative example, reliability and excellent in te pins of durability.

Particularly as can be known, the bonding part is that the number of the post more than 50% of maximum gauge is that the deviation of displacement at initial stage of sample No.2～25 of the embodiment 4 under the situation more than 30% is below 8%, the variation of the displacement after the long duration test also is below 4% continuously, littler, reliability and durability are more excellent.

In addition as can be known, the bonding part is that the number of the post more than 50% of maximum gauge is more than 50% and the mean value of the minimum diameter of post is sample No.3～5 and 7～25 of the embodiment 4 under the situation of 0.2 μ m, the deviation of the displacement at initial stage is below 7%, and is littler, reliability and excellent in te pins of durability.

On the other hand, the sample No.26 that is not provided with post outside scope of the present invention, the deviation of the displacement at initial stage is 20%, and is very poor, and in addition, the variation of the displacement after the long duration test also is 10% continuously, and very poor, reliability and durability are compared of the present invention poor.

(embodiment 5)

As embodiment 5, make lamination-type piezo actuator of the present invention by the mode of the following stated.

At first, manufacturing has mixed lead zirconate titanate (PbZrO ₃-PbTiO ₃) as the calcined powder of the piezoelectric ceramic of main component, binding agent, and the raw material of plasticizer, by the scraping blade manufactured thickness be the ceramic base material multi-layer sheet of 150 μ m as piezoelectric body layer 1.

To the multiple-plate single face of this ceramic base material, select following any, prepare to form 30 of the sheets of the thickness of 3 μ m by silk screen print method, as laminated body usefulness, that is: in the palladium-silver alloy that forms with any ratio of components, add the conductive paste of binding agent; In Ag, add the conductive paste of binding agent; In Cu, add the conductive paste of binding agent; In Ni, add the conductive paste of binding agent.Prepare the substrate of different therewith conduct protection portions, with they begin from the below lamination as protection portion with 30, as 30 that drive that laminate part uses, use as protection portion 30, through after exerting pressure, under 1000 ℃, burn till.

Thereafter, by cutter sweep, in the end of the internal electrode of the side of laminated body, having formed the degree of depth in the mode of an alternating floor is that 50 μ m, width are the groove of 50 μ m.

Secondly, to average grain diameter be silver powder 90 volume % and the remainder of the sheet of 2 μ m be 10 volume % with average grain diameter be 2 μ m silicon as main component, softening point is that total weight 100 mass parts of adding relative silver powder and glass powder in 640 ℃ the mixture of amorphous glass powder are the binding agent of 8 mass parts, fully mix and made silver-colored glass conductive paste.On demoulding type film, form the silver-colored glass conductive paste of making like this by silk screen printing, after the drying, peel off, obtain the sheet of silver-colored glass conductive paste from demoulding type film.Measure the original density of this sheet through Archimedes's method, be 6.5g/cm ³

Secondly, the sheet of described silver-colored glass conductive paste is replicated in the external electric pole-face face of column laminated body,, has formed the outer electrode that constitutes by the porous matter electric conductor that is the three dimensional network ocular structure 650 ℃ of following burn-backs 30 minutes.Also have, the voidage of the outer electrode of this moment is 40% through the result of the section photograph of graphical analysis device mensuration outer electrode 4.

Afterwards, lead is connected outer electrode, apply to the outer electrode of positive pole and negative pole by lead 15 minutes 3kV/mm DC electric field and the lamination-type piezo actuator that uses laminate type piezoelectric element has as shown in Figure 5 been made in the processing that polarizes.

Apply the direct voltage result of 170V to resulting laminate type piezoelectric element, obtain the displacement of 45 μ m on stack direction.In addition, at room temperature with the frequency of 150Hz to this laminate type piezoelectric element apply 0～+ alternating voltage of 170V, and carried out driving test.

And this laminate type piezoelectric element carries out long run test and reaches 1 * 10 until driving number of times ⁹Inferior, underproof quantity is before represented as disqualification rate.

The result is as shown in table 5.Also have, till the varied in thickness to 50 of the piezoelectrics of protection portion as shown in table 5～200 μ m,, used in palladium-silver alloy, silver, copper, the nickel any as absentee layer.In addition, absentee layer contains PZT as inorganic composition.

Table 5-1

No	A/B	Absentee layer
				1	0.04	99.99Ag-0.01Pd
2	0.04	99Ag-1Pd
			3	0.04	95Ag-5Pd
4	0.04	90Ag-10Pd
			5	0.04	70Ag-30Pd
6	0.04	50Ag-50Pd
			7	0.005	90Ag-10Pd
8	0.01	90Ag-10Pd
			9	0.02	90Ag-10Pd
10	0.03	90Ag-10Pd
			11	0.05	90Ag-10Pd
12	0.06	90Ag-10Pd
			13	0.07	90Ag-10Pd
14	0.08	90Ag-10Pd
			15	0.09	90Ag-10Pd
16	0.02	95Ag-5Pd
			17	0.08	95Ag-5Pd
18	0.04	90Ag-10Pd
			19	0.04	90Ag-10Pd
20	0.04	90Ag-10Pd
			21	0.04	90Ag-10Pd
22	0.04	90Ag-10Pd
			23	0.04	90Ag-10Pd
24	0.04	90Ag-10Pd
			25	0.04	90Ag-10Pd
26	0.04	90Ag-10Pd
			27	0.04	100Ag
28	0.04	100Cu
			29	0.04	100Ni
30	0.04	Glass

Table 5-2

No	Internal electrode	The thickness of piezoelectrics (μ m)	The content of the inorganic composition in the absentee layer (wt%)	Disqualification rate (%) after the continuous long duration test
					1	Identical with absentee layer	100	20	0.3
2	Identical with absentee layer	100	20	0.1
					3	Identical with absentee layer	100	20	0.2
4	Identical with absentee layer	100	20	0.2
					5	Identical with absentee layer	100	20	0.4
6	Identical with absentee layer	100	20	0.8
					7	Identical with absentee layer	100	20	3
8	Identical with absentee layer	100	20	2
					9	Identical with absentee layer	100	20	1
10	Identical with absentee layer	100	20	0.5
					11	Identical with absentee layer	100	20	0.4
12	Identical with absentee layer	100	20	0.5
					13	Identical with absentee layer	100	20	0.8
14	Identical with absentee layer	100	20	2
					15	Identical with absentee layer	100	20	3.5
16	Identical with absentee layer	100	20	0.8
					17	Identical with absentee layer	100	20	1.8
18	Identical with absentee layer	50	20	0.2
					19	Identical with absentee layer	70	20	0.2
20	Identical with absentee layer	150	20	0.3
					21	Identical with absentee layer	200	20	0.2
22	Identical with absentee layer	100	2	0.4
					23	Identical with absentee layer	100	10	0.2
24	Identical with absentee layer	100	30	0.2
					25	Identical with absentee layer	100	40	0.4
26	70Ag-30Pd	100	20	1
					27	Identical with absentee layer	100	20	0.2
28	Identical with absentee layer	100	20	0.2
					29	Identical with absentee layer	100	20	0.2
30	70Ag-30Pd	100	20	1

As shown in Table 5; will be on the same one side of the section vertical with stack direction; when the width that the beeline till the side of the outer thoughtful protection portion of described absentee layer is made as A, protection portion is made as B; A/B is that sample No.1～6,8～14 of 0.01～0.08 embodiments of the invention 5, the disqualification rate after 16～30 the continuous long duration test are below 2%; and compare with comparative example (No.7,15) little, and excellent in te pins of durability.

Especially as can be known, A/B is that sample No.1～6,9～13,16 of 0.02～0.07 embodiment 5, the disqualification rate after 18～30 the continuous long duration test are below 1%, and is littler, excellent in te pins of durability.

In addition, A/B is 0.02～0.07, and absentee layer contains metal, and internal electrode is made of the material identical with absentee layer, and the thickness of piezoelectrics is more than the 50 μ m, and absentee layer contains sample No.1～6,10～13,16,18～25 of the embodiment 5 of the above inorganic composition of 2wt%, the disqualification rate after 27～29 the continuous long duration test is below 0.8%, and is littler, excellent in te pins of durability.

On the other hand, the A/B outside the scope of the present invention is very poor less than 0.01 sample No.7, the A/B disqualification rate after greater than the long duration test of 0.08 sample No.15, is more than 3%, and on durability, it is poor to compare product of the present invention.

(industrial utilizability)

Laminate type piezoelectric element of the present invention can be used in piezoelectric transformer. In addition, laminate type piezoelectric element of the present invention can be used in the lamination-type piezo actuator that the precision positioning device such as the injection apparatus that carries at the ink of automobile fuel or ink-jet printer etc., Optical devices or the anti-locking apparatus of vibration etc. use. In addition, can be used in the sensor element that carries at combustion pressure sensor, seismological sensor, acceleration transducer, load sensor, ultrasound sensors, voltage sensitive sensor, yaw rate sensor etc., and use the laminate type piezoelectric element that uses on the component of piezolectric gyroscope, Piezoelectric switches, piezoelectric transformer, piezoelectricity breaker.

Claims (31)

1. laminate type piezoelectric element has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode, be connected with described outer electrode in described second side, it is characterized in that

1 * 10 ⁹The rate of change with respect to the element displacement before the Continuous Drive of the element displacement after the Continuous Drive more than inferior is in 5%.

2. laminate type piezoelectric element has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode, be connected with described outer electrode in described second side, it is characterized in that

1 * 10 ⁹The rate of change of the component resistance before the Continuous Drive of the component resistance after the Continuous Drive more than inferior is in 5%.

3. laminate type piezoelectric element according to claim 1 and 2 is characterized in that,

The maximum rate of change of the element displacement in the Continuous Drive is in 5%.

4. laminate type piezoelectric element according to claim 1 and 2 is characterized in that,

1 * 10 ⁹The size changing rate with respect to the gauge of the piezoelectric body layer before the Continuous Drive of the gauge of the piezoelectric body layer after the inferior above Continuous Drive is in 5%.

5. laminate type piezoelectric element according to claim 1 and 2 is characterized in that,

The maximum rate of change of the component resistance in the Continuous Drive is in 5%.

6. laminate type piezoelectric element has: laminated body, and it is stacked piezoelectric body layer and internal electrode and form alternatively; Outer electrode, it is formed at first side and second side of this laminated body respectively, a wherein side the internal electrode of adjacent internal electrode, be connected with described outer electrode in described first side, the opposing party's internal electrode is connected with outer electrode in second side, it is characterized in that

Be provided with post, described post runs through described internal electrode, and links the piezoelectric body layer that clips this internal electrode and subtend.

7. laminate type piezoelectric element according to claim 6 is characterized in that,

It is all more than 30% that the diameter of the bonding part of above-mentioned post and piezoelectric body layer is that the number of the post more than 50% of the maximum gauge of post accounts for.

8. according to claim 6 or 7 described laminate type piezoelectric elements, it is characterized in that,

The mean value of the minimum diameter of above-mentioned post is more than the 0.2 μ m.

9. according to each described laminate type piezoelectric element in the claim 6～8, it is characterized in that,

There are 5～150 in the every 1mm of above-mentioned post.

10. according to each described laminate type piezoelectric element in the claim 6～9, it is characterized in that,

The piezoelectrics material coefficient of thermal expansion difference of above-mentioned post and the described piezoelectric body layer of formation is below 3 * 10-5/ ℃.

11. according to each described laminate type piezoelectric element in the claim 6～10, it is characterized in that,

Above-mentioned post is by constituting with piezoelectrics material identical materials.

12. according to each described laminate type piezoelectric element in the claim 1～11, it is characterized in that,

Described laminated body down, comprises the alternatively inertia protection portion of the described piezoelectric body layer of lamination and absentee layer thereon,

To be made as A from the beeline of the side of the outer thoughtful described inertia protection portion of described absentee layer, when protecting the width of portion to be made as B inertia, A/B is 0.01～0.08.

13. laminate type piezoelectric element according to claim 12 is characterized in that,

In described absentee layer, contain metal.

14. according to claim 12 or 13 described laminate type piezoelectric elements, it is characterized in that,

Described absentee layer is made of the material identical with the internal electrode of described piezoelectric body layer.

15. according to each described laminate type piezoelectric element in the claim 12～14, it is characterized in that,

The thickness of described piezoelectric body layer is more than the 50 μ m.

16. according to each described laminate type piezoelectric element in the claim 12～15, it is characterized in that,

Described absentee layer contain metal oxide, nitride, and carbide in any inorganic composition.

17. according to each described laminate type piezoelectric element in the claim 12～16, it is characterized in that,

Described absentee layer contains the above inorganic composition of 2wt%.

18. according to each described laminate type piezoelectric element in the claim 1～17, it is characterized in that,

Metal constituent in the described internal electrode, with VIII family metal and/or Ib family metal as main component.

19. laminate type piezoelectric element according to claim 18 is characterized in that,

In weight %, be made as M1 at content with the VIII family metal in the described internal electrode, when the content of Ib family metal is made as M2, satisfy 0＜M1≤15,85≤M2＜100, M1+M2=100.

20. according to claim 18 or 19 described laminate type piezoelectric elements, it is characterized in that,

Described VIII family metal is more than at least a among Ni, Pt, Pd, Rh, Ir, Ru, the Os, and Ib family metal is more than at least a among Cu, Ag, the Au.

21. according to each described laminate type piezoelectric element in the claim 18～20, it is characterized in that,

Described VIII family metal is more than at least a among Pt, the Pd, and Ib family metal is more than at least a among Ag, the Au.

22. according to each described laminate type piezoelectric element in the claim 18～20, it is characterized in that,

Described VIII family metal is Ni.

23. according to each described laminate type piezoelectric element in the claim 18～20, it is characterized in that,

Described Ib family metal is Cu.

24. according to each described laminate type piezoelectric element in the claim 1～23, it is characterized in that,

In described internal electrode, add the metal constituent, and add oxide, nitride or carbide.

25. laminate type piezoelectric element according to claim 24 is characterized in that,

Described oxide is with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is as main component.

26. according to each described laminate type piezoelectric element in the claim 1～25, it is characterized in that,

Described piezoelectric body layer with perofskite type oxide as main component.

27. laminate type piezoelectric element according to claim 26 is characterized in that,

Described piezoelectric body layer is with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is as main component.

28. according to each described laminate type piezoelectric element in the claim 1～27, it is characterized in that,

The firing temperature of described laminated body is more than 900 ℃ but below 1000 ℃.

29. according to each described laminate type piezoelectric element in the claim 1～25, it is characterized in that,

Departing from before and after burn till of composition in the described internal electrode is below 5%.

30. according to each described laminate type piezoelectric element in the claim 1～29, it is characterized in that,

Expose at the described internal electrode of the side of described laminated body and the described internal electrode that does not expose the end by the end and alternatively to constitute, described internal electrode that does not expose in described end and the described piezoelectric body layer between the described outer electrode partly are formed with groove, are filled with the Young's modulus insulator lower than described piezoelectric body layer in this groove.

31. according to each described laminate type piezoelectric element in the claim 1～30, it is characterized in that,

Described internal electrode contains the space, and the space shared area ratio long-pending with respect to the entire profile of the section of described internal electrode is 5～70%.

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