JP2003086853A - Laminated piezoelectric element, its manufacturing method, and injection equipment - Google Patents

Laminated piezoelectric element, its manufacturing method, and injection equipment

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Publication number
JP2003086853A
JP2003086853A JP2002050252A JP2002050252A JP2003086853A JP 2003086853 A JP2003086853 A JP 2003086853A JP 2002050252 A JP2002050252 A JP 2002050252A JP 2002050252 A JP2002050252 A JP 2002050252A JP 2003086853 A JP2003086853 A JP 2003086853A
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JP
Japan
Prior art keywords
conductive
protruding
piezoelectric element
columnar
laminated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2002050252A
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Japanese (ja)
Other versions
JP3667289B2 (en
Inventor
Shigenobu Nakamura
成信 中村
Koki Ashida
幸喜 芦田
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Kyocera Corp
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Kyocera Corp
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Priority to JP2002050252A priority Critical patent/JP3667289B2/en
Publication of JP2003086853A publication Critical patent/JP2003086853A/en
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Publication of JP3667289B2 publication Critical patent/JP3667289B2/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H01L41/0472—
    • H01L41/0838—

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  • Fuel-Injection Apparatus (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a laminated piezoelectric element in which disconnection does not occur between external electrodes and internal electrodes even when the element is continuously driven for a long period under a high-electric field and high-pressure condition and which is excellent in durability. SOLUTION: This laminated piezoelectric element is provided with a columnar laminate 1a constituted by alternately laminating a plurality of piezoelectric layers 1 and a plurality of internal electrodes 2 upon another, and a pair of external electrodes 4 which are respectively provided on both side faces of the laminate 1a and to which the internal electrodes 2 are connected alternately at every other layer. Projecting conductive terminals 5 protruded from the side faces of the laminate 1a are provided at the end sections of the internal electrodes 2 at every other layer, and are bonded to the external electrodes 4 composed of plate-shaped conductive members 4a.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、積層型圧電素子及
びその製法並びに噴射装置に関し、例えば、自動車用燃
料噴射装置、光学装置等の精密位置決め装置や振動防止
用の駆動素子等に用いられる積層型圧電素子及びその製
法並びに噴射装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric element, a method of manufacturing the laminated piezoelectric element, and an injection device, for example, a laminated device used for a precision positioning device such as a fuel injection device for an automobile or an optical device, a drive element for preventing vibration, and the like. TECHNICAL FIELD The present invention relates to a piezoelectric element, a manufacturing method thereof, and an injection device.

【０００２】[0002]

【従来技術】従来より、積層型圧電素子としては、圧電
体と内部電極を交互に積層した積層型圧電アクチュエー
タが知られている。積層型圧電アクチュエータには、同
時焼成タイプと、圧電磁器と内部電極板を交互に積層し
たスタックタイプとの２種類に分類されており、低電圧
化、製造コスト低減の面から考慮すると、同時焼成タイ
プの積層型圧電アクチュエータが薄層化に対して有利で
あるために、その優位性を示しつつある。2. Description of the Related Art Hitherto, as a laminated piezoelectric element, a laminated piezoelectric actuator in which piezoelectric bodies and internal electrodes are alternately laminated has been known. Multi-layer piezoelectric actuators are classified into two types: co-firing type and stack type in which piezoelectric ceramics and internal electrode plates are alternately laminated. Considering low voltage and manufacturing cost, co-firing The advantage of the laminated piezoelectric actuator of the type is being demonstrated because it is advantageous for thinning.

【０００３】図１０は、従来の積層型圧電アクチュエー
タを示すもので、このアクチュエータでは、圧電体５１
と内部電極５２が交互に積層されて柱状積層体５３が形
成され、その積層方向における両端面には不活性層５５
が積層されている。内部電極５２は、その一方の端部が
左右交互に絶縁体６１で被覆され、その上から帯状外部
電極７０が内部電極５２と左右各々一層おきに導通する
ように形成されている。帯状外部電極７０上には、さら
にリード線７６が半田７７により固定されている。FIG. 10 shows a conventional laminated piezoelectric actuator. In this actuator, a piezoelectric body 51 is used.
And internal electrodes 52 are alternately laminated to form a columnar laminated body 53, and an inactive layer 55 is formed on both end faces in the laminating direction.
Are stacked. The inner electrode 52 is formed such that one end of the inner electrode 52 is alternately covered with the insulator 61, and the strip-shaped outer electrodes 70 are electrically connected to the inner electrode 52 on every other layer. A lead wire 76 is further fixed on the strip-shaped external electrode 70 by solder 77.

【０００４】ところで、近年においては、小型の圧電ア
クチュエータで大きな圧力下において大きな変位量を確
保するため、より高い電界を印加し、長期間連続駆動さ
せることが行われている。By the way, in recent years, in order to secure a large amount of displacement under a large pressure with a small piezoelectric actuator, a higher electric field is applied and continuous driving is performed for a long period of time.

【０００５】[0005]

【発明が解決しようとする課題】しかしながら、上記し
た圧電アクチュエータでは、高電界、高圧力下で長期間
連続駆動させた場合、圧電体５１間に形成された内部電
極５２と、正極、負極用の外部電極７０との間で剥離が
発生し、一部の圧電体５１に電圧供給されなくなり、駆
動中に変位特性が変化するという問題があった。However, in the above-described piezoelectric actuator, when continuously driven under a high electric field and a high pressure for a long period of time, the internal electrodes 52 formed between the piezoelectric bodies 51 and the positive and negative electrodes are formed. There is a problem that peeling occurs between the external electrode 70 and a voltage is not supplied to a part of the piezoelectric body 51, and the displacement characteristic changes during driving.

【０００６】例えば、特開平４−２３７１７２号公報に
は、柱状積層体の側面に露出した内部電極の端部が、一
層おきにガラスからなる絶縁層で被覆されるとともに、
内部電極とその上下の圧電体が強固に接合され、内部電
極の端部を絶縁する絶縁層が外部電極の凹部内に収容さ
れて、外部電極と内部電極との絶縁性が確保された積層
型圧電アクチュエータが開示されているが、このような
圧電アクチュエータでは、高電界、高圧力下で長期間連
続駆動させた場合、ガラスからなる絶縁層に割れが生
じ、この割れを介して内部電極と外部電極との間でショ
ートが発生し、一部の圧電体に電圧が供給されなくな
り、駆動中に変位特性が変化するという問題があった。[0006] For example, in Japanese Patent Laid-Open No. 4-237172, the end portions of the internal electrodes exposed on the side surfaces of the columnar laminated body are covered with an insulating layer made of glass every other layer.
A laminated type in which the internal electrode and the piezoelectric bodies above and below the electrode are firmly bonded, and an insulating layer that insulates the end of the internal electrode is housed in the recess of the external electrode to ensure insulation between the external electrode and the internal electrode. Although a piezoelectric actuator is disclosed, in such a piezoelectric actuator, when the piezoelectric actuator is continuously driven under a high electric field and a high pressure for a long period of time, a crack is generated in an insulating layer made of glass, and the internal electrode and the outside are broken through the crack. There is a problem that a short circuit occurs between the electrodes and a voltage is not supplied to a part of the piezoelectric body, and the displacement characteristic changes during driving.

【０００７】即ち、柱状積層体は、圧電体と内部電極と
の積層方向に伸縮するため、内部電極の端部およびその
近傍の圧電体に設けられた高ヤング率のガラスからなる
絶縁層が、長期間連続駆動による伸縮動作に耐えきれず
に破壊され、この破壊部分を介して内部電極と外部電極
間でショートが発生し易いという問題があった。That is, since the columnar laminated body expands and contracts in the laminating direction of the piezoelectric body and the internal electrode, the insulating layer made of high Young's modulus glass provided on the piezoelectric body at the end of the internal electrode and in the vicinity thereof, There is a problem in that it cannot withstand the expansion and contraction operation due to continuous driving for a long period of time and is broken, and a short circuit easily occurs between the internal electrode and the external electrode via this broken portion.

【０００８】また、特開平７−２８３４５１号公報や特
開平８−５１２４０号公報などには、一層おきの内部電
極の端部にメッキにより導電性凸部を形成することが開
示されているが、該導電性凸部と積層体との接合強度が
弱いために、駆動中に前記導電性凸部と内部電極端部が
剥離し、圧電体の一部に電圧が供給されなくなり、変位
特性が低下するといった問題があった。Further, Japanese Unexamined Patent Publication No. 7-283451 and Japanese Unexamined Patent Publication No. 8-51240 disclose that conductive protrusions are formed by plating on the end portions of every other internal electrode. Since the bonding strength between the conductive convex portion and the laminated body is weak, the conductive convex portion and the end portion of the internal electrode are separated during driving, the voltage is not supplied to a part of the piezoelectric body, and the displacement characteristic is deteriorated. There was a problem of doing.

【０００９】本発明は、高電界、高圧力下で長期間連続
駆動させた場合でも、外部電極と内部電極とが断線する
ことがなく、耐久性に優れた積層型圧電素子及びその製
法並びに噴射装置を提供することを目的とする。The present invention provides a laminated piezoelectric element excellent in durability without disconnection between the external electrode and the internal electrode even when continuously driven for a long time under a high electric field and a high pressure, a method for producing the same, and a jet method. The purpose is to provide a device.

【００１０】[0010]

【課題を解決するための手段】本発明の積層型圧電素子
は、複数の圧電体と複数の内部電極とを交互に積層して
なる柱状積層体と、該柱状積層体の側面に設けられ、前
記内部電極が一層おきに交互に接続された一対の外部電
極とを具備してなる積層型圧電素子であって、前記内部
電極の端部に一層おきに前記柱状積層体の側面から突出
する突起状導電性端子を設け、該突起状導電性端子と、
板状導電部材からなる外部電極とを接合してなることを
特徴とする。A laminated piezoelectric element of the present invention is provided with a columnar laminated body formed by alternately laminating a plurality of piezoelectric bodies and a plurality of internal electrodes, and provided on a side surface of the columnar laminated body. A laminated piezoelectric element comprising a pair of external electrodes in which the internal electrodes are alternately connected to each other, and protrusions protruding from the side surface of the columnar laminated body at every other end of the internal electrodes. A conductive terminal, and the protruding conductive terminal,
It is characterized by being joined to an external electrode made of a plate-shaped conductive member.

【００１１】本発明の積層型圧電素子では、内部電極の
端部に一層おきに柱状積層体の側面から突出する突起状
導電性端子を設け、該突起状導電性端子と、板状導電部
材からなる外部電極とを接合したため、アクチュエータ
が積層方向に駆動すると、突起状導電性端子が変形して
アクチュエータの伸縮によって生じる応力を吸収するた
め、高電界、高圧力下で長期間連続運転させた場合で
も、外部電極と内部電極との断線を抑制することがで
き、耐久性を大幅に向上できる。In the laminated piezoelectric element of the present invention, protruding conductive terminals projecting from the side surface of the columnar laminated body are provided at every other end of the internal electrode, and the protruding conductive terminals and the plate-shaped conductive member are connected to each other. When the actuator is driven in the stacking direction, the protruding conductive terminals are deformed to absorb the stress generated by the expansion and contraction of the actuator, so that it is operated continuously for a long time under a high electric field and pressure. However, disconnection between the external electrode and the internal electrode can be suppressed, and the durability can be significantly improved.

【００１２】また、本発明では、突起状導電性端子の根
元部が、柱状積層体の側面に形成されたケイ素含有層に
埋設されていることを特徴とする。Further, the present invention is characterized in that the root portion of the protruding conductive terminal is embedded in the silicon-containing layer formed on the side surface of the columnar laminated body.

【００１３】このような積層型圧電素子では、突起状導
電性端子の根元部が、柱状積層体の側面の圧電体表面に
形成されたケイ素含有層に埋設しているため、ケイ素含
有層が、柱状積層体の側面における圧電体表面に強固に
接合しており、このケイ素含有層に突起状導電性端子の
根元部が埋設され、これにより、突起状導電性端子を内
部電極の端部に強固に接合したまま、保持することがで
き、高電界、高圧力下で長期間連続駆動させた場合で
も、外部電極と内部電極とが断線することがなく、耐久
性に優れた積層型圧電素子を提供することができる。In such a laminated piezoelectric element, since the root of the protruding conductive terminal is embedded in the silicon-containing layer formed on the piezoelectric body surface on the side surface of the columnar laminated body, the silicon-containing layer is It is firmly bonded to the piezoelectric surface on the side surface of the columnar laminated body, and the root portion of the protruding conductive terminal is embedded in this silicon-containing layer, so that the protruding conductive terminal is firmly attached to the end of the internal electrode. A laminated piezoelectric element that can be held while being bonded to, and has excellent durability without disconnection between external electrodes and internal electrodes even when continuously driven under a high electric field and high pressure for a long time. Can be provided.

【００１４】さらに、本発明では、ケイ素含有層の厚み
が２〜１００μｍであることが望ましい。これにより、
突起状導電性端子を内部電極の端部にさらに強固に接合
保持でき、外部電極と内部電極との断線をさらに抑制す
ることができる。これは、ケイ素含有層の厚みを２μｍ
以上とすることにより、突起状導電性端子と、内部電
極、柱状積層体との接合強度を十分強固にすることがで
き、駆動中に突起状導電性端子が内部電極から剥離する
といった問題が生じるのを防ぐことができ、また、厚み
を１００μｍ以下とすることにより、ケイ素含有層によ
り圧電体の特性が低下することを防ぐことができる。Furthermore, in the present invention, the thickness of the silicon-containing layer is preferably 2 to 100 μm. This allows
The protruding conductive terminal can be more firmly joined and held to the end portion of the internal electrode, and disconnection between the external electrode and the internal electrode can be further suppressed. This is because the thickness of the silicon-containing layer is 2 μm.
By the above, the bonding strength between the protruding conductive terminal, the internal electrode, and the columnar laminate can be sufficiently strengthened, and the problem arises that the protruding conductive terminal is separated from the internal electrode during driving. Can be prevented, and the thickness of 100 μm or less can prevent the characteristics of the piezoelectric body from being deteriorated by the silicon-containing layer.

【００１５】さらに、本発明では、突起状導電性端子の
周りにケイ素含有層の***部が形成されていることが望
ましい。ケイ素含有層の***部が突起状導電性端子を補
佐することになり、突起状導電性端子と、内部電極、柱
状積層体との接合強度をさらに強固なものとすることが
でき、高電界下で連続に駆動させた場合でも、外部電極
と内部電極が断線することなく、耐久性を大幅に向上す
ることができる。Further, in the present invention, it is desirable that a raised portion of the silicon-containing layer is formed around the protruding conductive terminal. The raised portion of the silicon-containing layer assists the protruding conductive terminal, so that the bonding strength between the protruding conductive terminal, the internal electrode, and the columnar laminate can be further strengthened. Even when it is continuously driven by, the durability can be significantly improved without disconnection of the external electrode and the internal electrode.

【００１６】また、本発明では、各突起状導電性端子と
外部電極とが、前記突起状導電性端子の先端長さの５０
％以上の部分で接合していることが望ましい。これは、
突起状導電性端子と、板状導電部材からなる外部電極と
の接合が、各々の突起状導電性端子の先端長さの５０％
以上の部分で行われるので、突起状導電性端子と外部電
極の接合部の抵抗を十分低くすることができ、大電流を
流し高速で駆動させる場合においても、突起状導電性端
子と外部電極の接合部において局所発熱が生じることが
なく、耐久性を大幅に向上させることができる。Further, in the present invention, each of the protruding conductive terminals and the external electrode has a length equal to 50 of the tip length of the protruding conductive terminal.
It is desirable that the joints be made at a percentage of at least%. this is,
The protrusion-shaped conductive terminals are joined to the external electrodes made of a plate-shaped conductive member by 50% of the tip length of each protrusion-shaped conductive terminal.
Since it is performed in the above part, it is possible to sufficiently reduce the resistance of the joint portion between the protruding conductive terminal and the external electrode, and even when driving a large current at a high speed, the protruding conductive terminal and the external electrode Local heat generation does not occur at the joint, and durability can be greatly improved.

【００１７】さらに、本発明では、板状導電部材の厚み
が５０μｍ以下であることが望ましい。板状導電部材の
厚みが５０μｍよりも大きい場合には、板状導電部材が
アクチュエータの伸縮に追従できずに板状導電部材と突
起状導電性端子の間、若しくは突起状導電性端子と内部
電極の間で断線を起こし易くなるからである。従って、
板状導電部材の厚みを５０μｍ以下とすることにより、
アクチュエータを連続駆動させた場合にも、アクチュエ
ータの伸縮に充分追従でき、外部電極と内部電極が断線
するといった問題が生じるのを防ぐことができる。Further, in the present invention, it is desirable that the thickness of the plate-shaped conductive member is 50 μm or less. When the thickness of the plate-shaped conductive member is larger than 50 μm, the plate-shaped conductive member cannot follow the expansion and contraction of the actuator, and the space between the plate-shaped conductive member and the protruding conductive terminal or between the protruding conductive terminal and the internal electrode. This is because the wire breakage easily occurs between the two. Therefore,
By setting the thickness of the plate-shaped conductive member to 50 μm or less,
Even when the actuator is continuously driven, the expansion and contraction of the actuator can be sufficiently followed, and the problem of disconnection between the external electrode and the internal electrode can be prevented.

【００１８】また、本発明では、突起状導電性端子間に
おける板状導電部材に、スリット又は凹溝が形成されて
いることが望ましい。板状導電部材からなる外部電極に
スリット又は凹溝が形成されているので、柱状積層体の
伸縮に対応して外部電極が容易に変形して追従でき、外
部電極と突起状導電性端子との接続部、突起状導電性端
子と内部電極との接続部に無理な荷重が作用せず、これ
により、高電界、高圧力下で長期間連続駆動させた場合
でも、外部電極と内部電極とが断線することがなく、耐
久性を向上できる。Further, in the present invention, it is desirable that a slit or a groove is formed in the plate-shaped conductive member between the protruding conductive terminals. Since the slit or groove is formed in the external electrode made of the plate-shaped conductive member, the external electrode can be easily deformed and followed in response to the expansion and contraction of the columnar laminated body, and the external electrode and the protruding conductive terminal An unreasonable load does not act on the connection part and the connection part between the protruding conductive terminal and the internal electrode, which allows the external electrode and the internal electrode to separate even when continuously driven under a high electric field and a high pressure for a long period of time. Durability can be improved without breaking.

【００１９】また、本発明では、板状導電部材と柱状積
層体の側面との間に導電性樹脂が充填されていることが
望ましい。柱状積層体の伸縮によって発生する繰り返し
応力により、万が一板状導電部材が、そのスリット又は
凹溝から破断したとしても、破断した外部電極片同士は
導電性樹脂により接続されているため、内部電極に電界
を印加できる。Further, in the present invention, it is desirable that a conductive resin is filled between the plate-shaped conductive member and the side surface of the columnar laminated body. Due to the repeated stress generated by the expansion and contraction of the columnar laminated body, even if the plate-shaped conductive member is broken from the slit or the concave groove, the broken external electrode pieces are connected to each other by the conductive resin, so that the internal electrodes are An electric field can be applied.

【００２０】さらに、本発明では、板状導電部材の外面
に導電性補助部材を設けられていることが望ましい。板
状導電部材の外側に導電性補助部材を設けることにより
アクチュエータに大電流を投入し、高速で駆動させる場
合においても、外部電極が局所発熱を起こし断線するこ
とを防ぐことができ、耐久性を大幅に向上させることが
できる。Further, in the present invention, it is desirable that a conductive auxiliary member is provided on the outer surface of the plate-shaped conductive member. By providing a conductive auxiliary member on the outer side of the plate-shaped conductive member, it is possible to prevent local external heat from being generated and disconnection even when a large current is applied to the actuator and driven at high speed. It can be greatly improved.

【００２１】さらに、本発明では、導電性補助部材が、
導電性接着剤、導電性コイル、導電性波板、導電性繊維
集合体のうち少なくとも１種からなることが望ましい。
導電性補助部材が導電性接着剤からなる場合には、導電
性補助部材としてフレキシブルな導電性接着剤を用いる
ことにより、アクチュエータの伸縮に導電性補助部材が
十分追従することができ、駆動中における導電性補助部
材の断線を抑制できる。Further, in the present invention, the conductive auxiliary member is
It is desirable to be composed of at least one of a conductive adhesive, a conductive coil, a conductive corrugated sheet, and a conductive fiber aggregate.
When the conductive auxiliary member is made of a conductive adhesive, the conductive auxiliary member can sufficiently follow the expansion and contraction of the actuator by using a flexible conductive adhesive as the conductive auxiliary member, and It is possible to suppress disconnection of the conductive auxiliary member.

【００２２】導電性接着剤が、導電剤を分散させたポリ
イミド樹脂からなることが好ましい。この場合には、高
耐熱性を有するポリイミド樹脂を該導電性接着剤のマト
リックス成分とすることにより、高温で駆動させる場合
においても該導電性接着剤が劣化することがなく、高耐
久性を備えている積層型圧電素子を提供することができ
る。It is preferable that the conductive adhesive is made of a polyimide resin in which the conductive agent is dispersed. In this case, by using a polyimide resin having high heat resistance as a matrix component of the conductive adhesive, the conductive adhesive does not deteriorate even when it is driven at high temperature, and has high durability. It is possible to provide a laminated piezoelectric element having such a structure.

【００２３】また、導電性補助部材が導電性コイル、導
電性波板、導電性繊維集合体であり、該導電性補助部材
が板状導電部材に接合されていることが望ましい。この
場合には、導電性補助部材がアクチュエータの伸縮に追
従することができ、駆動中に該導電性補助部材が断線し
たり、該導電性補助部材と板状導電部材との間に応力を
生じ、該導電性補助部材が剥離するといった問題が生じ
るのを防ぐことができ、耐久性を大きく向上させること
ができる。Further, it is desirable that the conductive auxiliary member is a conductive coil, a conductive corrugated plate or a conductive fiber aggregate, and the conductive auxiliary member is joined to the plate-shaped conductive member. In this case, the conductive auxiliary member can follow expansion and contraction of the actuator, the conductive auxiliary member is disconnected during driving, or stress is generated between the conductive auxiliary member and the plate-shaped conductive member. The problem that the conductive auxiliary member is peeled off can be prevented, and the durability can be greatly improved.

【００２４】さらに、本発明では、突起状導電性端子と
板状導電部材が銀を主成分とすることが望ましい。これ
は、突起状導電性端子と板状導電部材の主成分を銀とす
ることにより、突起状導電性端子と内部電極の間、及び
突起状導電性端子と板状導電部材の間の接合強度を強固
にすることができ、アクチュエータを高電界下で駆動さ
せた場合にも、外部電極と内部電極が断線することな
く、耐久性を大きく向上させることができる。また、突
起状導電性端子と板状導電部材の主成分をヤング率の低
い銀とすることによりアクチュエータの駆動時に生じる
応力を十分吸収することができ、外部電極と内部電極と
の断線を抑制できる。Further, in the present invention, it is desirable that the protruding conductive terminals and the plate-shaped conductive member contain silver as a main component. This is because the main component of the protruding conductive terminal and the plate-shaped conductive member is silver, so that the bonding strength between the protruding conductive terminal and the internal electrode and between the protruding conductive terminal and the plate-shaped conductive member is increased. Can be strengthened, and even when the actuator is driven under a high electric field, the external electrode and the internal electrode are not disconnected, and the durability can be greatly improved. Also, by using silver having a low Young's modulus as the main component of the protruding conductive terminal and the plate-shaped conductive member, it is possible to sufficiently absorb the stress generated when the actuator is driven, and it is possible to suppress disconnection between the external electrode and the internal electrode. .

【００２５】さらに、本発明の積層型圧電素子の製法
は、複数の圧電体と複数の内部電極とを交互に積層して
なり、前記内部電極の端部が側面に露出した柱状積層体
を作製する工程と、該柱状積層体の側面に、導電性金属
粉末５０〜８０体積％とケイ素を主成分とするガラス粉
末２０〜５０体積％とからなる固形成分を含有する導電
性ペーストを塗布する工程と、該柱状積層体の側面に塗
布された導電性ペーストを加熱し、前記内部電極の端部
に前記柱状積層体の側面から突出する突起状導電性端子
を形成する工程と、該突起状導電性端子の先端部に板状
導電部材からなる外部電極を接続する工程とを具備する
方法である。Further, in the method for manufacturing a laminated piezoelectric element of the present invention, a columnar laminated body is produced in which a plurality of piezoelectric bodies and a plurality of internal electrodes are alternately laminated, and the end portions of the internal electrodes are exposed on the side surfaces. And a step of applying a conductive paste containing a solid component consisting of 50 to 80% by volume of a conductive metal powder and 20 to 50% by volume of a glass powder containing silicon as a main component on the side surface of the columnar laminate. And a step of heating the conductive paste applied to the side surface of the columnar laminated body to form a protruding conductive terminal projecting from the side surface of the columnar laminated body at the end portion of the internal electrode; And a step of connecting an external electrode made of a plate-shaped conductive member to the tip of the sex terminal.

【００２６】このような方法によれば、柱状積層体の側
面に、導電性金属粉末５０〜８０体積％とケイ素を主成
分とするガラス粉末２０〜５０体積％とからなる固形成
分を含有する導電性ペーストを塗布して、加熱すること
により、ガラスが溶融し、溶融したガラス中に存在する
導電性金属粒子が、内部電極の端部に集合し、柱状積層
体の側面から突出する突起状導電性端子が形成されると
ともに、柱状積層体の側面における圧電体表面に、拡散
した圧電体の成分とケイ素を含むケイ素含有層（ガラス
層）が形成され、このケイ素含有層により突起状導電性
端子の根元部が埋設され、突起状導電性端子を内部電極
端部に強固に接合することができる。According to such a method, the conductive material containing a solid component consisting of 50 to 80% by volume of the conductive metal powder and 20 to 50% by volume of the glass powder containing silicon as the main component is provided on the side surface of the columnar laminate. Glass is melted by applying a conductive paste and heating, and the conductive metal particles present in the melted glass are aggregated at the end of the internal electrode and protruded from the side surface of the columnar laminate to form a conductive protrusion. And a silicon-containing layer (glass layer) containing the diffused piezoelectric component and silicon is formed on the surface of the piezoelectric body on the side surface of the columnar laminated body, and the silicon-containing layer forms a protruding conductive terminal. The root portion of is embedded, and the protruding conductive terminal can be firmly bonded to the end portion of the internal electrode.

【００２７】ここで、導電性ペーストを加熱して形成さ
れた突起状導電性端子の高さバラツキが、前記突起状導
電性端子の平均高さの０．３倍以下であることが望まし
い。これは、突起状導電性端子の高さバラツキを突起状
導電性端子の平均高さの０．３倍以下とすることによ
り、該突起状導電性端子と、板状導電部材からなる外部
電極との接続を確実強固なものとすることができ、駆動
中に突起状導電性端子と外部電極が断線するといった問
題が生じるのを防ぐことができる。なお、本発明におい
て、突起状導電性端子の高さバラツキとは、各突起状導
電性端子の最大高さと最小高さの差をいう。Here, it is preferable that the height variation of the protruding conductive terminals formed by heating the conductive paste is 0.3 times or less of the average height of the protruding conductive terminals. This is because when the height variation of the protruding conductive terminals is set to 0.3 times or less of the average height of the protruding conductive terminals, the protruding conductive terminals and the external electrodes made of a plate-shaped conductive member are The connection can be made surely and firmly, and it is possible to prevent the problem that the protruding conductive terminal and the external electrode are disconnected during driving. In the present invention, the height variation of the protruding conductive terminals means the difference between the maximum height and the minimum height of each protruding conductive terminal.

【００２８】また、本発明の積層型圧電素子の製法は、
複数の圧電体と複数の内部電極とを交互に積層してな
り、前記内部電極の端部が側面に露出した柱状積層体を
作製する工程と、該柱状積層体の側面と板状導電部材か
らなる外部電極との間であって、一層おきの露出した内
部電極の端部及びその近傍の圧電体表面を被覆するよう
に、導電性金属粉末５０〜８０体積％とケイ素を主成分
とするガラス粉末２０〜５０体積％とからなる固形成分
を含有する導電性ペーストを介在させる工程と、該導電
性ペーストを加熱して、前記内部電極の端部に一層おき
に前記柱状積層体の側面から突出する突起状導電性端子
を形成するとともに、該突起状導電性端子の先端部に前
記外部電極を接合する工程とを具備する方法である。The method of manufacturing the laminated piezoelectric element of the present invention is as follows.
A step of producing a columnar laminated body in which a plurality of piezoelectric bodies and a plurality of internal electrodes are alternately laminated, and the end portions of the internal electrodes are exposed on the side surface; and the side surface of the columnar laminated body and the plate-shaped conductive member. Glass containing silicon as a main component in an amount of 50 to 80% by volume of conductive metal powder so as to cover the exposed end portions of the inner electrodes and the piezoelectric body surface in the vicinity thereof between the outer electrodes. A step of interposing a conductive paste containing a solid component consisting of 20 to 50% by volume of powder, and heating the conductive paste to protrude from the side surface of the columnar stacked body at every other end portion of the internal electrode. And a step of joining the external electrode to the tip end portion of the protruding conductive terminal.

【００２９】このような方法によれば、柱状積層体の側
面と板状導電部材からなる外部電極との間であって、一
層おきの露出した内部電極の端部及びその近傍の圧電体
表面を被覆するように、導電性金属粉末５０〜８０体積
％とケイ素を主成分とするガラス粉末２０〜５０体積％
とからなる固形成分を含有する導電性ペーストを介在さ
せ、加熱することにより、ガラスが溶融し、溶融したガ
ラス中に存在する導電性金属粒子が、内部電極の端部に
集合し、柱状積層体の側面から突出する突起状導電性端
子が形成されるとともに、該突起状導電性端子の先端部
に外部電極に接合することができる。また、同時に柱状
積層体の側面における圧電体表面にケイ素含有層が形成
され、このケイ素含有層により突起状導電性端子の根元
部が埋設され、突起状導電性端子を内部電極端部に強固
に接合することができる。According to such a method, between the side surface of the columnar laminated body and the external electrode made of the plate-like conductive member, the exposed end portions of the internal electrodes and the piezoelectric surface in the vicinity thereof are exposed. 50 to 80% by volume of conductive metal powder and 20 to 50% by volume of glass powder containing silicon as a main component so as to cover
By interposing a conductive paste containing a solid component consisting of and heating, the glass is melted, and the conductive metal particles present in the melted glass are aggregated at the end of the internal electrode to form a columnar laminate. The protruding conductive terminal is formed so as to project from the side surface, and the tip end of the protruding conductive terminal can be bonded to the external electrode. At the same time, a silicon-containing layer is formed on the surface of the piezoelectric body on the side surface of the columnar laminated body, and the root portion of the protruding conductive terminal is embedded by this silicon-containing layer, so that the protruding conductive terminal is firmly attached to the internal electrode end. Can be joined.

【００３０】本発明の噴射装置は、噴射孔を有する収納
容器と、該収納容器内に収容された上記積層型圧電素子
と、該積層型圧電素子の駆動により前記噴射孔から液体
を噴出させるバルブとを具備するものである。The jetting device of the present invention comprises a container having a jetting hole, the laminated piezoelectric element housed in the casing, and a valve for ejecting a liquid from the jetting hole by driving the laminated piezoelectric element. And is equipped with.

【００３１】このような噴射装置では、上記したよう
に、積層型圧電素子が、外部電極と内部電極との断線を
抑制でき、耐久性を大幅に向上できるため、噴射装置の
耐久性をも向上できる。In such an ejecting apparatus, as described above, the laminated piezoelectric element can suppress the disconnection between the external electrode and the internal electrode and can greatly improve the durability, so that the durability of the ejecting apparatus is also improved. it can.

【００３２】[0032]

【発明の実施の形態】図１は本発明の積層型圧電アクチ
ュエータからなる積層型圧電素子の一形態を示すもの
で、（ａ）は斜視図、（ｂ）は（ａ）のＡ−Ａ’線に沿
った縦断面図、（ｃ）は（ａ）の一部を拡大して示す斜
視図、（ｄ）は内部電極と外部電極の接合部近傍の拡大
図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a laminated piezoelectric element comprising a laminated piezoelectric actuator according to the present invention. (A) is a perspective view, (b) is AA 'in (a). FIG. 3 is a vertical cross-sectional view taken along the line, (c) is a perspective view showing a part of (a) in an enlarged manner, and (d) is an enlarged view in the vicinity of a joint portion between an internal electrode and an external electrode.

【００３３】積層型圧電アクチュエータは、図１に示す
ように、複数の圧電体１と複数の内部電極２とを交互に
積層してなる四角柱状の柱状積層体１ａの側面におい
て、内部電極２の端部を一層おきに絶縁体３で被覆し、
絶縁体３で被覆していない内部電極２の端部に、積層型
圧電素子の伸縮方向に変形可能な突起状導電性端子５を
設け、該突起状導電性端子５に板状導電部材４ａからな
る外部電極４を接合し、各外部電極４にリード線６を接
続固定して構成されている。As shown in FIG. 1, the laminated piezoelectric actuator includes a plurality of piezoelectric bodies 1 and a plurality of internal electrodes 2 which are alternately laminated on the side surface of a rectangular columnar laminated body 1a. Every other edge is covered with an insulator 3,
At the end of the internal electrode 2 which is not covered with the insulator 3, a protruding conductive terminal 5 which is deformable in the expansion and contraction direction of the laminated piezoelectric element is provided, and the protruding conductive terminal 5 is connected to the plate conductive member 4a. The external electrodes 4 are joined to each other, and the lead wire 6 is connected and fixed to each external electrode 4.

【００３４】圧電体１は、例えば、チタン酸ジルコン酸
鉛Ｐｂ（Ｚｒ，Ｔｉ）Ｏ3（以下ＰＺＴと略す）、或い
はチタン酸バリウムＢａＴｉＯ3を主成分とする圧電セ
ラミックス材料等で形成されている。この圧電セラミッ
クスは、その圧電特性を示す圧電歪み定数ｄ33が高いも
のが望ましい。The piezoelectric body 1 is made of, for example, lead zirconate titanate Pb (Zr, Ti) O 3 (hereinafter abbreviated as PZT) or a piezoelectric ceramic material containing barium titanate BaTiO 3 as a main component. . It is desirable that this piezoelectric ceramic has a high piezoelectric strain constant d 33 showing its piezoelectric characteristics.

【００３５】また、圧電体１の厚み、つまり内部電極２
間の距離は５０〜２５０μｍが望ましい。これは、積層
型圧電アクチュエータは電圧を印加してより大きな変位
量を得るために、積層数を増加させる方法がとられる
が、積層数を増加させた場合に圧電体１の厚みが厚すぎ
るとアクチュエータの小型化、低背化ができなくなり、
一方、圧電体１の厚みが薄すぎると絶縁破壊しやすいか
らである。The thickness of the piezoelectric body 1, that is, the internal electrode 2
The distance between them is preferably 50 to 250 μm. This is because the laminated piezoelectric actuator has a method of increasing the number of laminated layers in order to apply a voltage to obtain a larger displacement amount, but when the number of laminated layers is increased, the piezoelectric body 1 is too thick. The actuator cannot be made smaller and the height cannot be reduced,
On the other hand, if the piezoelectric body 1 is too thin, dielectric breakdown is likely to occur.

【００３６】圧電体１の間には内部電極２が配されてい
るが、この内部電極２は銀−パラジウム等の金属材料で
形成されており、各圧電体１に所定の電圧を印加し、圧
電体１に逆圧電効果による変位を起こさせる作用をな
す。Internal electrodes 2 are arranged between the piezoelectric bodies 1. The internal electrodes 2 are made of a metallic material such as silver-palladium, and a predetermined voltage is applied to each piezoelectric body 1. This serves to cause the piezoelectric body 1 to be displaced by the inverse piezoelectric effect.

【００３７】また、突起状導電性端子５が形成された柱
状積層体１ａの側面に一層おきに深さ５０〜５００μ
ｍ、積層方向の幅３０〜２００μｍの溝が形成されてお
り、この溝内にガラス、エポキシ樹脂、ポリイミド樹
脂、ポリアミドイミド樹脂、シリコーンゴム等が充填さ
れて絶縁体３が形成されている。この絶縁体３は、柱状
積層体１ａとの接合を強固とするために、柱状積層体１
ａの変位に対して追従する弾性率が低い材料、具体的に
はシリコーンゴム等からなることが好適である。Further, every other layer has a depth of 50 to 500 μm on the side surface of the columnar laminated body 1a on which the protruding conductive terminals 5 are formed.
m, a groove having a width of 30 to 200 μm in the stacking direction is formed, and the insulator 3 is formed by filling the groove with glass, epoxy resin, polyimide resin, polyamideimide resin, silicone rubber, or the like. This insulator 3 is used for strengthening the joint with the columnar laminated body 1a.
It is preferable to use a material having a low elastic modulus that follows the displacement of a, specifically, silicone rubber or the like.

【００３８】突起状導電性端子５と絶縁体３は、外部電
極４が形成された柱状積層体１ａの側面に露出した内部
電極２に、交互に形成されている。The protruding conductive terminals 5 and the insulators 3 are alternately formed on the internal electrodes 2 exposed on the side surfaces of the columnar laminate 1a on which the external electrodes 4 are formed.

【００３９】即ち、溝内に充填された絶縁体３により内
部電極２の端部が互い違いに一層おきに絶縁され、内部
電極２の絶縁されていない他方の端部は、突起状導電性
端子５を介して板状導電部材４ａからなる外部電極４と
接合されている。That is, the end portions of the internal electrodes 2 are alternately insulated by the insulator 3 filled in the groove, and the other non-insulated end portions of the internal electrodes 2 are protruded conductive terminals 5. It is joined to the external electrode 4 composed of the plate-shaped conductive member 4a via.

【００４０】柱状積層体１ａの対向する側面には、それ
ぞれ板状導電部材４ａからなる外部電極４が突起状導電
性端子５を介して接続固定されており、該外部電極４に
は、積層されている内部電極２が一層おきに電気的に接
続されている。この板状導電部材４ａからなる外部電極
４は、接続されている各内部電極２に圧電体１を逆圧電
効果により変位させるに必要な電圧を共通に供給する作
用をなす。External electrodes 4 each made of a plate-shaped conductive member 4a are connected and fixed to opposite side surfaces of the columnar laminated body 1a through projecting conductive terminals 5, and are laminated on the external electrodes 4. The internal electrodes 2 are electrically connected to every other layer. The external electrode 4 composed of the plate-shaped conductive member 4a has a function of commonly supplying a voltage necessary for displacing the piezoelectric body 1 to each connected internal electrode 2 by the inverse piezoelectric effect.

【００４１】さらに、外部電極４にはリード線６が半田
により接続固定されている。このリード線６は外部電極
４を外部の電圧供給部に接続する作用をなす。Further, a lead wire 6 is connected and fixed to the external electrode 4 by soldering. The lead wire 6 serves to connect the external electrode 4 to an external voltage supply section.

【００４２】そして、本発明では、上記したように板状
導電部材４ａからなる外部電極４が突起状導電性端子５
を介して内部電極２と接続されている。このため、アク
チュエータを高電界、高圧力下で長期間連続駆動させた
場合でも、突起状導電性端子５がアクチュエータの伸縮
によって生じる応力を吸収し、該外部電極４と内部電極
２の断線を抑制することができ、耐久性に優れたアクチ
ュエータを提供することができる。In the present invention, as described above, the external electrode 4 made of the plate-shaped conductive member 4a is provided with the protruding conductive terminal 5.
It is connected to the internal electrode 2 via. Therefore, even when the actuator is continuously driven under a high electric field and a high pressure for a long period of time, the protruding conductive terminal 5 absorbs the stress generated by the expansion and contraction of the actuator, and the disconnection between the external electrode 4 and the internal electrode 2 is suppressed. Therefore, it is possible to provide an actuator having excellent durability.

【００４３】後述するケイ素含有層から突出した突起状
導電性端子５の積層方向と同一方向の幅Ｂは、図１
（ｃ）に示すように、外部電極４と内部電極２との接続
部の抵抗を低くし、且つアクチュエータの駆動時に生じ
る応力を十分に吸収するという点から、１μｍ以上且つ
圧電体１厚みの１／２以下であることが望ましい。特に
は、幅Ｂは５〜２５μｍが望ましい。The width B in the same direction as the stacking direction of the protruding conductive terminals 5 protruding from the silicon-containing layer described later is as shown in FIG.
As shown in (c), the resistance of the connection portion between the external electrode 4 and the internal electrode 2 is reduced, and the stress generated when the actuator is driven is sufficiently absorbed, and the thickness of the piezoelectric body 1 is 1 μm or more and 1 It is desirable that it is / 2 or less. Particularly, the width B is preferably 5 to 25 μm.

【００４４】また、ケイ素含有層から突出した突起状導
電性端子５の突出高さｈは、アクチュエータの伸縮によ
って生じる応力を十分に吸収するという点から、圧電体
１厚みの１／２０以上であることが望ましい。特には突
出高さｈは、１５〜５０μｍが望ましい。Further, the protruding height h of the protruding conductive terminal 5 protruding from the silicon-containing layer is 1/20 or more of the thickness of the piezoelectric body 1 from the viewpoint of sufficiently absorbing the stress generated by the expansion and contraction of the actuator. Is desirable. Particularly, the protrusion height h is preferably 15 to 50 μm.

【００４５】さらに、板状導電部材４ａの厚みｔは、ア
クチュエータの伸縮に追従し、外部電極４と突起状導電
性端子５の間、若しくは突起状導電性端子５と内部電極
２の間で断線を生じないという点から、５０μｍ以下で
あることが望ましい。Further, the thickness t of the plate-shaped conductive member 4a follows the expansion and contraction of the actuator, and disconnection between the external electrode 4 and the protruding conductive terminal 5 or between the protruding conductive terminal 5 and the internal electrode 2. It is preferable that the thickness is 50 μm or less from the viewpoint of not causing.

【００４６】また、突起状導電性端子５は、銀、ニッケ
ル、銅、金、アルミニウム等の導電性を備えた金属及び
それらの合金からなり、アクチュエータの伸縮によって
生じる応力を十分に吸収するという点から、ヤング率の
低い銀、若しくは銀が主成分の合金が望ましい。The protruding conductive terminal 5 is made of a conductive metal such as silver, nickel, copper, gold, or aluminum, and an alloy thereof, and sufficiently absorbs the stress generated by the expansion and contraction of the actuator. Therefore, silver having a low Young's modulus or an alloy containing silver as a main component is preferable.

【００４７】さらに、板状導電部材４ａは、銀、ニッケ
ル、銅、金、アルミニウム等の導電性を備えた金属及び
それらの合金からなり、このうち、突起状導電性端子５
との接合強度が強く、ヤング率が低いという点から、
銀、若しくは銀が主成分の合金が望ましい。Further, the plate-like conductive member 4a is made of a metal having conductivity such as silver, nickel, copper, gold, aluminum and alloys thereof, and of these, the protruding conductive terminal 5 is provided.
From the point that the joint strength with is strong and the Young's modulus is low,
Silver or an alloy containing silver as a main component is preferable.

【００４８】突起状導電性端子５と板状導電部材４ａか
らなる外部電強４との接合は、荷重を加えた状態で７０
０〜９５０℃で熱処理することにより、主成分である銀
が突起状導電性端子５と板状導電部材４ａ間を相互に拡
散し、いわゆる銀の拡散接合によってなされる。また、
内部電極２と突起状導電性端子５の接合部はケイ素含有
層１０中に埋設しており、内部電極２を構成する銀−パ
ラジウムと、突起状導電性端子５を構成する銀が相互拡
散し、連続的に内部電極２と突起状導電性端子５が接合
されている。The protrusion-shaped conductive terminal 5 and the external electromotive force 4 made of the plate-shaped conductive member 4a are bonded to each other by applying a load 70
By heat treatment at 0 to 950 ° C., the main component, silver, diffuses between the protruding conductive terminals 5 and the plate-shaped conductive member 4a, and this is achieved by so-called silver diffusion bonding. Also,
The joint portion between the internal electrode 2 and the protruding conductive terminal 5 is embedded in the silicon-containing layer 10, and silver-palladium forming the internal electrode 2 and silver forming the protruding conductive terminal 5 interdiffuse. The internal electrodes 2 and the protruding conductive terminals 5 are continuously joined.

【００４９】即ち、本発明では、突起状導電性端子５の
根元部５ａが、柱状積層体１ａの側面における圧電体１
表面に形成されたケイ素含有層１０に埋設され、突起状
導電性端子５の先端部が板状導電部材４ａからなる外部
電極４に接続されている。That is, according to the present invention, the root portion 5a of the protruding conductive terminal 5 has the piezoelectric body 1 on the side surface of the columnar laminated body 1a.
It is embedded in the silicon-containing layer 10 formed on the surface, and the tip end portion of the protruding conductive terminal 5 is connected to the external electrode 4 composed of the plate-shaped conductive member 4a.

【００５０】ここで、突起状導電性端子５の根元部５ａ
は、内部電極２と突起状導電性端子５の接続部近傍にお
ける突起状導電性端子５の部分を意味するが、突起状導
電性端子５を形成する銀と内部電極２を構成する銀−パ
ラジウムが相互拡散し、連続的に内部電極２と突起状導
電性端子５が接続されているため、内部電極２の厚みよ
りも大きくなり始めた箇所が内部電極２と突起状導電性
端子５の接続部となり、それよりも先端側が突起状導電
性端子５の根元部５ａとなる。Here, the root portion 5a of the protruding conductive terminal 5
Means the portion of the protruding conductive terminal 5 in the vicinity of the connecting portion between the internal electrode 2 and the protruding conductive terminal 5, and silver forming the protruding conductive terminal 5 and silver-palladium forming the internal electrode 2 Are mutually diffused and the internal electrode 2 and the protruding conductive terminal 5 are continuously connected, so that the portion where the thickness starts to become larger than the thickness of the internal electrode 2 is connected to the internal electrode 2 and the protruding conductive terminal 5. And the tip side thereof becomes the root portion 5a of the protruding conductive terminal 5.

【００５１】このケイ素含有層１０の最小厚みｄは、突
起状導電性端子５と、内部電極２及び柱状積層体１ａと
の接合強度を強固なものにし、且つケイ素含有層１０に
より圧電体１の特性が低下するのを防止するという点か
ら、２〜１００μｍであることが望ましく、特には５〜
１５μｍが望ましい。このような厚みのケイ素含有層１
０を形成するためには、５０〜８０体積％の銀等の導電
性金属粉末と、残部がケイ素を主成分とし、軟化点６０
０〜９５０℃の２０〜５０体積％のガラス粉末とからな
る固形成分に、バインダーを加えて導電性ペーストを作
製し、該導電性ペーストを柱状積層体１ａの側面に塗布
し、ガラスの軟化点以上の温度、即ち７００〜９５０℃
で焼き付けを行うことにより達成できる。The minimum thickness d of the silicon-containing layer 10 strengthens the bonding strength between the protruding conductive terminal 5 and the internal electrode 2 and the columnar laminate 1a, and the silicon-containing layer 10 allows the piezoelectric body 1 to have a strong bonding strength. From the viewpoint of preventing the characteristics from deteriorating, the thickness is preferably 2 to 100 μm, particularly 5 to 5 μm.
15 μm is desirable. Silicon-containing layer 1 having such a thickness
In order to form 0, 50 to 80% by volume of a conductive metal powder such as silver and the balance silicon as a main component, and a softening point of 60
A binder is added to a solid component consisting of 20 to 50% by volume of glass powder at 0 to 950 ° C. to prepare a conductive paste, and the conductive paste is applied to the side surface of the columnar laminate 1a to obtain a softening point of glass. Above temperature, ie 700-950 ° C
This can be achieved by baking in.

【００５２】ここで、ケイ素含有層１０の厚みｄが２μ
ｍより小さい場合には、突起状導電性端子５と、内部電
極２、柱状積層体１ａとの接合強度が弱く、駆動中に該
突起状導電性端子５が剥離し、内部電極２の一部に電圧
が供給されなくなり変位特性が低下する傾向があり、一
方、ケイ素含有層１０の厚みｄが１００μｍより大きい
場合には、絶縁体３を充填する溝を形成する工程で圧電
体１にクラックが生じたり、圧電体１の圧電特性が低下
したりする傾向があるからである。Here, the thickness d of the silicon-containing layer 10 is 2 μm.
If it is smaller than m, the bonding strength between the protruding conductive terminal 5, the internal electrode 2 and the columnar laminated body 1a is weak, and the protruding conductive terminal 5 peels off during driving, resulting in a part of the internal electrode 2. However, if the thickness d of the silicon-containing layer 10 is larger than 100 μm, the piezoelectric body 1 is not cracked in the step of forming the groove for filling the insulator 3. This is because it tends to occur or the piezoelectric characteristics of the piezoelectric body 1 deteriorate.

【００５３】ケイ素含有層１０中のケイ素の分布は表面
近傍が最も多く、内部側にいくほど、即ち深さが深くな
るにつれ減少していき、逆に圧電体１を形成するＰｂは
深さが浅くなるにつれ減少している。なお、ケイ素は圧
電体１の内部においても少量の不純物若しくは添加物と
して存在するが、圧電体１内部の均一の分布状態で存在
するケイ素の量が増加し始めるところから柱状積層体１
ａ表面までの距離をケイ素含有層１０の厚みｄとする。The distribution of silicon in the silicon-containing layer 10 is largest in the vicinity of the surface and decreases toward the inner side, that is, as the depth becomes deeper, and conversely, Pb forming the piezoelectric body 1 has a deeper depth. It decreases as it becomes shallower. Although silicon exists as a small amount of impurities or additives even inside the piezoelectric body 1, the columnar laminated body 1 starts when the amount of silicon existing in a uniform distribution state inside the piezoelectric body 1 starts to increase.
The distance to the surface a is defined as the thickness d of the silicon-containing layer 10.

【００５４】また、本発明では、突起状導電性端子５と
内部電極２及び柱状積層体１ａとの接合をさらに確実強
固なものとするために、図１（ｄ）に示すように、ケイ
素含有層１０が突起状導電性端子５を補佐するように、
突起状導電性端子５の根元部５ａの周りにはケイ素含有
層１０の***部１０ａが形成されている。即ち、突起状
導電性端子５の根元部５ａはケイ素含有層１０の***部
１０ａに埋設されている。ケイ素含有層１０の***部１
０ａは、ケイ素含有層１０の最小厚みｄを有する部分か
らの高さが１〜５μｍであることが望ましい。突起状導
電性端子５の断面形状は、土筆状若しくはきのこ状が望
ましい。In addition, in the present invention, in order to further firmly and firmly bond the protruding conductive terminals 5 to the internal electrodes 2 and the columnar laminate 1a, as shown in FIG. As the layer 10 assists the protruding conductive terminal 5,
A raised portion 10 a of the silicon-containing layer 10 is formed around the root portion 5 a of the protruding conductive terminal 5. That is, the root portion 5 a of the protruding conductive terminal 5 is embedded in the raised portion 10 a of the silicon-containing layer 10. Raised portion 1 of silicon-containing layer 10
The height of 0a from the portion having the minimum thickness d of the silicon-containing layer 10 is preferably 1 to 5 μm. The cross-sectional shape of the protruding conductive terminal 5 is preferably a brush or mushroom shape.

【００５５】また、突起状導電性端子５のケイ素含有層
１０からの突出高さｈ、即ちケイ素含有層１０の最小厚
みｄを有する部分から板状導電部材４ａまでの距離は、
アクチュエータの伸縮によって生じる応力を十分に吸収
するという点から、圧電体１厚みの１／２０以上である
ことが望ましい。特には突出高さｈは、１５〜５０μｍ
が望ましい。The protruding height h of the protruding conductive terminal 5 from the silicon-containing layer 10, that is, the distance from the portion having the minimum thickness d of the silicon-containing layer 10 to the plate-shaped conductive member 4a is:
The thickness is preferably 1/20 or more of the thickness of the piezoelectric body 1 in order to sufficiently absorb the stress generated by the expansion and contraction of the actuator. Particularly, the protrusion height h is 15 to 50 μm.
Is desirable.

【００５６】さらに、本発明では、図２に示すように、
各突起状導電性端子５と板状導電部材４ａとが、前記突
起状導電性端子５の先端長さＬの５０％以上の部分で接
合されている。これにより、突起状導電性端子５と板状
導電部材４ａとの接合部の抵抗を十分低くし、大電流を
流し高速でアクチュエータを駆動させた場合において
も、突起状導電性端子５と板状導電部材４ａの接合部に
おいて、局所発熱が生じるのを防ぐことができる。特に
は、８０％以上が好ましい。このように、各々の突起状
導電性端子５と板状導電部材４ａの接合を突起状導電性
端子５の先端長さＬの５０％以上とするためには、突起
状導電性端子５の作製時における突起状導電性端子５の
高さバラツキを突起状導電性端子５の平均高さｈの０．
３倍以下とし、また、均一な荷重を印加した状態で７０
０〜９５０℃で熱処理すればよい。Further, in the present invention, as shown in FIG.
Each of the protruding conductive terminals 5 and the plate-shaped conductive member 4a are joined to each other at 50% or more of the tip length L of the protruding conductive terminals 5. As a result, the resistance of the joint between the protruding conductive terminal 5 and the plate-shaped conductive member 4a is sufficiently lowered, and even when the actuator is driven at a high speed by passing a large current, the protruding conductive terminal 5 and the plate-shaped conductive member 4a are driven. It is possible to prevent local heat generation from occurring at the joint portion of the conductive member 4a. Particularly, 80% or more is preferable. In this way, in order to bond each protruding conductive terminal 5 and the plate-shaped conductive member 4a to 50% or more of the tip length L of the protruding conductive terminal 5, the protruding conductive terminals 5 are manufactured. When the average height h of the protruding conductive terminals 5 is 0.
3 times or less, and 70 with a uniform load applied
The heat treatment may be performed at 0 to 950 ° C.

【００５７】さらに、外部電極４にはリード線６が半田
により接続固定されている。このリード線６は外部電極
４を外部の電圧供給部に接続する作用をなす。Further, the lead wire 6 is connected and fixed to the external electrode 4 by soldering. The lead wire 6 serves to connect the external electrode 4 to an external voltage supply section.

【００５８】本発明の積層型圧電素子の製法について説
明する。まず、柱状積層体１ａを作製する。複数の圧電
体１と複数の内部電極２とを交互に積層して成る柱状積
層体１ａは、ＰＺＴ等の圧電セラミックスの仮焼粉末
と、アクリル系、ブチラール系等の有機高分子から成る
バインダーと、ＤＢＰ（フタル酸ジオチル）、ＤＯＰ
（フタル酸ジブチル）等の可塑剤とを混合してスラリー
を作製し、該スラリーを周知のドクターブレード法やカ
レンダーロール法等のテープ成型法により圧電体１とな
るセラミックグリーンシートを作製する。A method of manufacturing the laminated piezoelectric element of the present invention will be described. First, the columnar laminated body 1a is manufactured. A columnar laminated body 1a formed by alternately laminating a plurality of piezoelectric bodies 1 and a plurality of internal electrodes 2 is a calcined powder of piezoelectric ceramics such as PZT and a binder made of an organic polymer such as an acrylic or butyral type. , DBP (diotyl phthalate), DOP
A slurry is prepared by mixing with a plasticizer such as (dibutyl phthalate), and the slurry is prepared by a known tape molding method such as a doctor blade method or a calendar roll method to prepare a ceramic green sheet to be the piezoelectric body 1.

【００５９】次に、例えば、銀−パラジウム粉末にバイ
ンダー、可塑剤等を添加混合して導電性ペーストを作製
し、これを前記各グリーンシートの上面にスクリーン印
刷等によって１〜４０μｍの厚みに印刷する。Next, for example, a binder, a plasticizer, etc. are added to and mixed with silver-palladium powder to prepare a conductive paste, which is printed on the upper surface of each green sheet to a thickness of 1 to 40 μm by screen printing or the like. To do.

【００６０】そして、上面に導電性ペーストが印刷され
たグリーンシートを積層し、この積層体について所定の
温度で脱バインダーを行った後、９００〜１２００℃で
焼成することによって作製される。Then, a green sheet having a conductive paste printed on the upper surface thereof is laminated, the binder is debindered at a predetermined temperature, and then baked at 900 to 1200 ° C.

【００６１】その後、柱状積層体１ａの対向する側面
に、図３（ａ）に示すように、例えば、粒径０．１〜１
０μｍの銀粉末を５０〜８０体積％と、残部が粒径０．
１〜１０μｍでケイ素を主成分とする軟化点が６００〜
９５０℃のガラス粉末２０〜５０体積％からなる混合物
に、バインダーを加えて作製した銀ガラス導電性ペース
ト２１を塗布し、ガラスの軟化点以上の温度の７００〜
９５０℃で焼き付けを行うことにより、銀ガラス導電性
ペースト２１中の銀が内部電極２端部に集合し、図３
（ｂ）に示すように、土筆状やきのこ状の突起状導電性
端子５及びケイ素含有層１０を形成することができる。Then, as shown in FIG. 3A, for example, a grain size of 0.1 to 1 is provided on the opposite side surfaces of the columnar laminated body 1a.
50 μm to 80% by volume of silver powder of 0 μm, and the balance of grain size is 0.
1 to 10 μm and a softening point containing silicon as a main component is 600 to
A silver glass conductive paste 21 prepared by adding a binder to a mixture of 20 to 50% by volume of glass powder at 950 ° C. is applied, and the temperature is 700 to 700 at a temperature equal to or higher than the softening point of glass.
By baking at 950 ° C., the silver in the silver glass conductive paste 21 gathers at the end portions of the internal electrodes 2, and FIG.
As shown in (b), the brush-shaped or mushroom-shaped protruding conductive terminals 5 and the silicon-containing layer 10 can be formed.

【００６２】即ち、ペーストにガラス成分を分散させて
おくことにより、焼き付け時にガラスが軟化し、この状
態において圧電体１には拡散しにくい銀が内部電極２の
端部に拡散して寄り集まるため、図１（ｂ）に示すよう
な突起状導電性端子５を形成できる。That is, by dispersing the glass component in the paste, the glass is softened during baking, and in this state silver, which is difficult to diffuse in the piezoelectric body 1, diffuses and gathers at the end of the internal electrode 2. The protruding conductive terminal 5 as shown in FIG. 1B can be formed.

【００６３】この突起状導電性端子５は柱状積層体１ａ
の側面の一部に形成されており、レール状に形成され、
その長さは板状導電部材４ａからなる外部電極４の幅と
ほぼ同一とされている。尚、突起状導電性端子５の長さ
は、図２に示すように、外部電極４の幅よりも短くても
良い。This protruding conductive terminal 5 is a columnar laminate 1a.
It is formed on a part of the side surface of the
The length thereof is substantially the same as the width of the external electrode 4 made of the plate-shaped conductive member 4a. The length of the protruding conductive terminal 5 may be shorter than the width of the external electrode 4, as shown in FIG.

【００６４】銀ガラス導電性ペースト２１中の銀粉末を
５０〜８０体積％、残部のガラス粉末を２０〜５０体積
％としたのは、銀粉末が５０体積％より少ない場合に
は、突起状導電端子５を構成する銀成分が少ないため、
形成される突起状導電性端子５の突出高さｈが小さくな
り、一方銀粉末が８０体積％よりも多い場合には、銀ガ
ラス導電性ペースト２１中の固形分残部であるガラス成
分が相対的に少なくなるため、該銀ガラス導電性ペース
ト２１の焼き付け時に溶融するガラス成分も必然的に少
なくなり、銀成分が内部電極２端部に集合しにくくな
り、突起状導電性端子５の突出高さｈが低くなるためで
ある。The silver powder in the silver glass conductive paste 21 is set to 50 to 80% by volume and the balance of the glass powder is set to 20 to 50% by volume when the silver powder is less than 50% by volume. Since the silver component forming the terminal 5 is small,
When the protruding height h of the protruding conductive terminal 5 formed is small and the silver powder is more than 80% by volume, the glass component which is the solid content remaining in the silver glass conductive paste 21 is relatively small. Since the silver component becomes less, the glass component that melts when the silver glass conductive paste 21 is baked is inevitably reduced, and it becomes difficult for the silver component to collect at the end portion of the internal electrode 2, and the protruding height of the protruding conductive terminal 5 increases. This is because h becomes low.

【００６５】また、特にケイ素含有層１０の***部１０
ａを有効に形成するには、銀ガラス導電性ペースト２１
中の銀粉末を６０〜７０体積％、ガラス粉末を３０〜４
０体積％とするのが望ましい。In particular, the ridge 10 of the silicon-containing layer 10
To effectively form a, the silver glass conductive paste 21
60 to 70% by volume of silver powder and 30 to 4 of glass powder
It is preferably 0% by volume.

【００６６】熱処理後の突起状導電性端子５の高さバラ
ツキ（最大値−最小値）は、突起状導電性端子５と板状
導電部材４ａの接続を確実なものとするため、突起状導
電性端子５の高さｈの平均値の０．３倍以下であること
が望ましく、特には、０．１倍以下が望ましい。なお、
突起状導電性端子５の高さｈのバラツキを突起状導電性
端子５の高さｈの平均値の０．３倍以下にするために
は、該突起状導電性端子５を形成するために柱状積層体
１ａ側面に予め塗布する銀ガラス導電性ペースト２１の
塗布厚みのバラツキを小さくすればよい。The height variation (maximum value-minimum value) of the protruding conductive terminals 5 after the heat treatment ensures the connection between the protruding conductive terminals 5 and the plate-shaped conductive member 4a. It is desirable that the height h of the sex terminal 5 is 0.3 times or less, and particularly 0.1 times or less. In addition,
In order to make the variation of the height h of the protruding conductive terminals 5 0.3 times or less of the average value of the height h of the protruding conductive terminals 5, the protruding conductive terminals 5 are formed. It suffices to reduce variations in the coating thickness of the silver glass conductive paste 21 that is previously coated on the side surfaces of the columnar stacked body 1a.

【００６７】上述のように突起状導電性端子５を形成し
た後、図３（ｃ）に示すようにダイシング装置等により
突起状導電性端子５の形成された柱状積層体１ａの側面
に一層おきに溝を形成する。After forming the protruding conductive terminals 5 as described above, one layer is placed on the side surface of the columnar laminated body 1a on which the protruding conductive terminals 5 are formed by a dicing device or the like as shown in FIG. 3 (c). To form a groove.

【００６８】その後、図３（ｄ）に示すように、銀から
なる板状導電部材４ａを突起状導電性端子５に当接させ
押圧して荷重を加え、７００〜９５０℃で熱処理するこ
とにより、主成分である銀が突起状導電性端子５と板状
導電部材４ａ間を相互に拡散し、いわゆる銀の拡散接合
によって接合される。Thereafter, as shown in FIG. 3 (d), the plate-shaped conductive member 4a made of silver is brought into contact with the protruding conductive terminals 5 and pressed to apply a load and heat-treated at 700 to 950.degree. The main component, silver, diffuses between the protruding conductive terminal 5 and the plate-shaped conductive member 4a, and is joined by so-called silver diffusion bonding.

【００６９】なお、この際に加える荷重は圧力にして、
２〜５００ｋＰａが望ましい。これは、圧力が２ｋＰａ
以下の場合には、圧力が低いために突起状導電性端子５
と板状導電部材４ａとの間で拡散接合が十分になされず
に、該接合部の強度が低くなり、一方、５００ｋＰａ以
上の場合には圧力が高すぎるために、突起状導電性端子
５が変形してしまう恐れがあるためである。The load applied at this time is pressure,
2-500 kPa is desirable. This has a pressure of 2 kPa
In the following cases, the protruding conductive terminal 5 is used because the pressure is low.
And the plate-shaped conductive member 4a are not sufficiently diffusion-bonded to each other, and the strength of the bonded portion is reduced. On the other hand, when the pressure is 500 kPa or more, the pressure is too high, so that the protruding conductive terminal 5 is This is because there is a risk of deformation.

【００７０】その後、溝部に絶縁体３を充填し、リード
線６を接続することにより本発明の積層型圧電素子が完
成する。Then, the groove 3 is filled with the insulator 3 and the lead wire 6 is connected to complete the laminated piezoelectric element of the present invention.

【００７１】なお、柱状積層体１ａの側面に一層おきに
溝を形成した後に、銀ガラス導電性ペースト２１を塗布
し、焼き付けを行い突起状導電性端子５を形成してもよ
い。Alternatively, the protruding conductive terminals 5 may be formed by forming grooves on the side surfaces of the columnar laminate 1a and then applying the silver glass conductive paste 21 and baking the grooves.

【００７２】次に、本発明の積層型圧電素子の他の製法
について説明する。上述と同様に柱状積層体１ａを形成
した後、該柱状積層体１ａの側面に一層おきに溝を形成
する。Next, another method for manufacturing the laminated piezoelectric element of the present invention will be described. After forming the columnar laminated body 1a in the same manner as described above, grooves are formed on the side surface of the columnar laminated body 1a in every other layer.

【００７３】その後、該柱状積層体１ａの溝以外の柱状
積層体１ａに露出した内部電極２およびこの内部電極２
の近傍の圧電体１表面に、上述と同様の銀ガラス導電性
ペースト２１を塗布乾燥し、この銀ガラス導電性ペース
ト２１に板状導電部材４ａを押圧するように荷重を加え
た状態で７００〜９５０℃で熱処理することにより、銀
ガラス導電性ペースト２１中のガラスが溶融し、溶融し
たガラス中に存在する銀成分が内部電極２の端部に集合
し、柱状積層体１ａの側面から突出する突起状導電性端
子５が形成されるとともに、該突起状導電性端子５の先
端部を板状導電部材４ａに接続することができる。After that, the internal electrodes 2 and the internal electrodes 2 exposed on the columnar laminate 1a other than the grooves of the columnar laminate 1a are exposed.
The same silver glass conductive paste 21 as described above is applied and dried on the surface of the piezoelectric body 1 in the vicinity of, and a load is applied to the silver glass conductive paste 21 so as to press the plate-shaped conductive member 4a. By the heat treatment at 950 ° C., the glass in the silver glass conductive paste 21 is melted, and the silver component present in the melted glass is collected at the end of the internal electrode 2 and protrudes from the side surface of the columnar laminated body 1 a. The protruding conductive terminal 5 is formed, and the tip end portion of the protruding conductive terminal 5 can be connected to the plate-shaped conductive member 4a.

【００７４】尚、予め、柱状積層体１ａの溝以外の柱状
積層体１ａに露出した内部電極２およびこの内部電極２
の近傍の圧電体１表面に対応する板状導電部材４ａの部
分に、銀ガラス導電性ペースト２１を塗布乾燥し、この
板状導電部材４ａを柱状積層体１ａに押圧するように荷
重を加えた状態で熱処理してもよい。また、板状導電部
材４ａの全面に銀ガラス導電性ペーストを塗布乾燥し、
この板状導電部材４ａを、導電性ペースト塗布面側を柱
状積層体１ａの内部電極２が露出した面に押圧し、熱処
理しても、突起状導電性端子５が形成し、その先端部を
板状導電部材４ａに接続することができる。この場合に
はさらに工程を短縮することができる。The internal electrodes 2 and the internal electrodes 2 exposed in the columnar laminated body 1a other than the grooves of the columnar laminated body 1a are previously exposed.
The silver glass conductive paste 21 was applied and dried on the portion of the plate-shaped conductive member 4a corresponding to the surface of the piezoelectric body 1 in the vicinity of, and a load was applied so as to press the plate-shaped conductive member 4a against the columnar laminated body 1a. You may heat-process in a state. Further, a silver glass conductive paste is applied and dried on the entire surface of the plate-shaped conductive member 4a,
Even when the plate-shaped conductive member 4a is pressed against the surface where the internal electrode 2 of the columnar laminated body 1a is exposed with the conductive paste application surface side, and the heat treatment is performed, the protruding conductive terminal 5 is formed, and the tip portion thereof is formed. It can be connected to the plate-shaped conductive member 4a. In this case, the process can be further shortened.

【００７５】その後、溝部に絶縁体３を充填し、リード
線６を接続することにより本発明の積層型圧電素子が完
成する。Then, the groove 3 is filled with the insulator 3 and the lead wire 6 is connected to complete the laminated piezoelectric element of the present invention.

【００７６】そして、リード線６を介して一対の外部電
極４に０．１〜３ｋＶ／ｍｍの直流電圧を印加し、柱状
積層体１ａを分極処理することによって、製品としての
積層型圧電アクチュエータが完成し、リード線６を外部
の電圧供給部に接続し、リード線６及び外部電極４を介
して内部電極２に電圧を印加させれば、各圧電体１は逆
圧電効果によって大きく変位し、これによって例えばエ
ンジンに燃料を噴射供給する自動車用燃料噴射弁として
機能する。Then, a DC voltage of 0.1 to 3 kV / mm is applied to the pair of external electrodes 4 via the lead wires 6 to polarize the columnar laminated body 1a, whereby a laminated piezoelectric actuator as a product is obtained. When completed, the lead wire 6 is connected to an external voltage supply unit, and a voltage is applied to the internal electrode 2 via the lead wire 6 and the external electrode 4, each piezoelectric body 1 is largely displaced by the inverse piezoelectric effect, With this, for example, it functions as a fuel injection valve for an automobile that injects fuel to the engine.

【００７７】以上のように構成された積層型圧電素子
は、板状導電部材４ａからなる外部電極４が突起状導電
性端子５を介して内部電極２と接続されているため、ア
クチュエータを高電界下、連続で駆動させた場合でも、
突起状導電性端子５が変形して突起状導電性端子５が駆
動時に生じる応力を十分に吸収できるため、外部電極４
と内部電極２との間でスパークが生じるといった問題を
防ぐことができ、高信頼性のアクチュエータを提供する
ことができる。In the laminated piezoelectric element configured as described above, since the external electrode 4 made of the plate-shaped conductive member 4a is connected to the internal electrode 2 via the protruding conductive terminal 5, the actuator is operated in a high electric field. Even when driven continuously,
Since the protruding conductive terminals 5 are deformed and the protruding conductive terminals 5 can sufficiently absorb the stress generated during driving, the external electrodes 4
It is possible to prevent a problem that a spark occurs between the internal electrode 2 and the internal electrode 2, and it is possible to provide a highly reliable actuator.

【００７８】図４は、板状導電部材に凹溝を形成した積
層型圧電アクチュエータを示すもので、この積層型圧電
アクチュエータでは、板状導電部材４ａに、突起状導電
性端子５間であって、内部電極２の端部とほぼ平行に凹
溝１１が形成されている。凹溝１１は、突起状導電性端
子５間にそれぞれ形成されており、その深さは板状導電
部材４ａの厚み方向の１／２以上の深さとされている。
尚、凹溝１１は、外部電極４の幅全体にわたって形成す
る必要はなく、幅方向に一部に形成しても良い。FIG. 4 shows a laminated piezoelectric actuator in which a groove is formed in a plate-shaped conductive member. In this laminated piezoelectric actuator, a plate-shaped conductive member 4a is provided between the protruding conductive terminals 5. A groove 11 is formed substantially parallel to the end of the internal electrode 2. The recessed grooves 11 are formed between the protruding conductive terminals 5, respectively, and the depth thereof is 1/2 or more in the thickness direction of the plate-shaped conductive member 4a.
The concave groove 11 does not have to be formed over the entire width of the external electrode 4, but may be formed in a part in the width direction.

【００７９】また、柱状積層体１ａの側面と板状導電部
材４ａ間に導電性樹脂４ｂが充填され、板状導電部材４
ａの露出した面も導電性樹脂４ｂにより被覆されてい
る。A conductive resin 4b is filled between the side surface of the columnar laminated body 1a and the plate-shaped conductive member 4a, and the plate-shaped conductive member 4 is formed.
The exposed surface of a is also covered with the conductive resin 4b.

【００８０】以上のように構成された積層型圧電アクチ
ュエータは、外部電極４に凹溝１１が形成されているの
で、柱状積層体１ａの伸縮に対応して外部電極４が容易
に変形して追従でき、外部電極４と突起状導電性端子５
との接続部、突起状導電性端子５と内部電極２との接続
部に無理な荷重が作用せず、これにより、高電界、高圧
力下で長期間連続駆動させた場合でも、外部電極４と内
部電極２とが断線することがなく、耐久性を向上でき
る。In the laminated piezoelectric actuator constructed as described above, since the groove 11 is formed in the external electrode 4, the external electrode 4 is easily deformed and follows the expansion and contraction of the columnar laminated body 1a. The external electrode 4 and the protruding conductive terminal 5
An unreasonable load does not act on the connection part between the external electrode 4 and the connection between the protruding conductive terminal 5 and the internal electrode 2, so that the external electrode 4 can be continuously driven even under a high electric field and a high pressure for a long period of time. Therefore, the internal electrode 2 is not disconnected and the durability can be improved.

【００８１】さらに、柱状積層体１ａの伸縮によって発
生する繰り返し応力により、万が一板状導電部材４ａか
らなる外部電極４が凹溝１１から破断したとしても、破
断した外部電極４片同士は導電性樹脂４ｂにより接続さ
れているため、内部電極２に電界を印加できる。Further, even if the external electrode 4 made of the plate-shaped conductive member 4a should break from the concave groove 11 due to the repeated stress generated by the expansion and contraction of the columnar laminated body 1a, the broken external electrode 4 pieces are made of conductive resin. Since they are connected by 4b, an electric field can be applied to the internal electrode 2.

【００８２】図５は、板状導電部材にスリットを形成し
た積層型圧電アクチュエータを示すもので、この積層型
圧電アクチュエータでは、板状導電部材４ａに、一方側
の端面から所定長さでスリット１３が形成されている。
このスリット１３の長さは、板状導電部材４ａの幅の２
／３以上の長さとされている。また、柱状積層体１ａの
側面と板状導電部材４ａ間に導電性樹脂４ｂが充填さ
れ、板状導電部材４ａの露出した面も導電性樹脂４ｂに
より被覆されている。FIG. 5 shows a laminated piezoelectric actuator in which a slit is formed in a plate-shaped conductive member. In this laminated piezoelectric actuator, the plate-shaped conductive member 4a has a slit 13 with a predetermined length from one end face. Are formed.
The length of the slit 13 is 2 times the width of the plate-shaped conductive member 4a.
The length is / 3 or more. A conductive resin 4b is filled between the side surface of the columnar laminated body 1a and the plate-shaped conductive member 4a, and the exposed surface of the plate-shaped conductive member 4a is also covered with the conductive resin 4b.

【００８３】このような積層型圧電アクチュエータであ
っても、上記図４に示した積層型圧電アクチュエータと
同様の効果を得ることができる。尚、作製時に、スリッ
ト１３を板状導電部材４ａからなる外部電極４の幅方向
に全体にわたって形成、即ち、予め板状導電部材４ａか
らなる外部電極４を、突起状導電性端子５間で分断して
おいても良い。Even with such a laminated piezoelectric actuator, the same effects as those of the laminated piezoelectric actuator shown in FIG. 4 can be obtained. At the time of fabrication, the slit 13 is formed over the entire width of the external electrode 4 made of the plate-shaped conductive member 4a, that is, the external electrode 4 made of the plate-shaped conductive member 4a is divided in advance between the protruding conductive terminals 5. You may keep it.

【００８４】尚、外部電極４に形成される凹溝１１やス
リット１３は、板状導電部材４ａを柱状積層体１ａの突
起状導電性端子５に接合した後に形成しても良いし、板
状導電部材４ａを突起状導電性端子５に接合する前に形
成しても良いが、板状導電部材４ａの突起状導電性端子
５への接合工程の作業性を考慮すると、板状導電部材４
ａを突起状導電性端子５に接合した後に形成することが
望ましい。The groove 11 and the slit 13 formed in the external electrode 4 may be formed after the plate-shaped conductive member 4a is bonded to the protruding conductive terminal 5 of the columnar laminated body 1a, or may be formed in the plate-shaped. The conductive member 4a may be formed before being joined to the protruding conductive terminal 5, but in view of workability in the process of joining the plate conductive member 4a to the protruding conductive terminal 5, the plate conductive member 4 is considered.
It is desirable to form it after joining a to the protruding conductive terminal 5.

【００８５】さらに、本発明では、図６に示すように、
板状導電部材４ａからなる外部電極４の外側に導電性補
助部材７を形成しても良い。この場合には、板状導電部
材４ａの外面に導電性補助部材７を設けることによりア
クチュエータに大電流を投入し、高速で駆動させる場合
においても、大電流を導電性補助部材７に流すことがで
き、外部電極４に流れる電流を低減できるという理由か
ら、外部電極４が局所発熱を起こし断線することを防ぐ
ことができ、耐久性を大幅に向上させることができる。Further, in the present invention, as shown in FIG.
The conductive auxiliary member 7 may be formed outside the external electrode 4 made of the plate-shaped conductive member 4a. In this case, by providing the conductive auxiliary member 7 on the outer surface of the plate-shaped conductive member 4a, a large current can be supplied to the actuator, and a large current can flow through the conductive auxiliary member 7 even when the actuator is driven at high speed. For this reason, the current flowing through the external electrode 4 can be reduced, so that the external electrode 4 can be prevented from causing local heat generation and disconnection, and the durability can be significantly improved.

【００８６】なお、導電性補助部材７はアクチュエータ
の伸縮に追従し、駆動中に該導電性補助部材７の断線を
防ぐ点から、フレキシブルな導電性接着剤７ａによって
形成されていることが好ましい。また、導電性接着剤７
ａにクラックが生じるのを防ぐという点から、金属等の
メッシュ若しくはメッシュ状の金属板を該導電性接着剤
７ａに埋設しても良い。The conductive auxiliary member 7 is preferably formed of a flexible conductive adhesive 7a in order to follow the expansion and contraction of the actuator and prevent disconnection of the conductive auxiliary member 7 during driving. In addition, the conductive adhesive 7
From the viewpoint of preventing cracks from occurring in a, a mesh of metal or the like or a mesh-shaped metal plate may be embedded in the conductive adhesive 7a.

【００８７】さらに、前記導電性接着剤７ａは高温で駆
動させる場合においても劣化しないという点から、高耐
熱を有するポリイミド樹脂に導電剤を分散させたものが
望ましい。Further, since the conductive adhesive 7a does not deteriorate even when it is driven at a high temperature, it is preferable that the conductive agent is dispersed in a polyimide resin having high heat resistance.

【００８８】また、本発明では、図７（ａ）、（ｂ）、
（ｃ）に示すように、導電性コイル７ｂ、若しくは導電
性波板７ｃ、若しくは導電性繊維集合体（ウール状）７
ｄにより導電性補助部材７を形成しても良い。この場合
には、導電性補助部材７がアクチュエータの伸縮に追従
することができ、駆動中に該導電性補助部材７が断線し
たり、該導電性補助部材７と外部電極４との間に応力を
生じ、該導電性補助部材７が剥離するといった問題を防
ぐことができ、耐久性を大きく向上させることができ
る。なお、前記導電性補助部材７と外部電極４との接続
は、ロウ材による接合や、導電性接着剤による接合が好
ましい。Further, according to the present invention, as shown in FIGS.
As shown in (c), the conductive coil 7b, the conductive corrugated plate 7c, or the conductive fiber aggregate (wool-like) 7
The conductive auxiliary member 7 may be formed by d. In this case, the conductive auxiliary member 7 can follow the expansion and contraction of the actuator, the conductive auxiliary member 7 is disconnected during driving, or stress is applied between the conductive auxiliary member 7 and the external electrode 4. The problem that the conductive auxiliary member 7 is peeled off can be prevented, and the durability can be greatly improved. The conductive auxiliary member 7 and the external electrode 4 are preferably connected by a brazing material or a conductive adhesive.

【００８９】導電性補助部材７としては、抵抗値及びヤ
ング率が低く、伸縮性に富み、また、アクチュエータの
断面積を小さくできるという点から、材質が銀の導電性
波板７ｃが望ましい。The conductive auxiliary member 7 is preferably a conductive corrugated plate 7c made of silver because it has a low resistance value and Young's modulus, is highly stretchable, and can reduce the cross-sectional area of the actuator.

【００９０】本発明の積層型圧電素子はこれらに限定さ
れるものではなく、本発明の要旨を逸脱しない範囲であ
れば種々の変更は可能である。The laminated piezoelectric element of the present invention is not limited to these, and various modifications can be made without departing from the scope of the present invention.

【００９１】また、上記例では、柱状積層体１ａの対向
する側面に外部電極４を形成した例について説明した
が、本発明では、例えば隣設する側面に一対の外部電極
を形成してもよい。In the above example, the external electrodes 4 are formed on the opposite side surfaces of the columnar laminated body 1a. However, in the present invention, for example, a pair of external electrodes may be formed on adjacent side surfaces. .

【００９２】図８は、本発明の噴射装置を示すもので、
図において符号３１は収納容器を示している。この収納
容器３１の一端には噴射孔３３が設けられ、また収納容
器３１内には、噴射孔３３を開閉することができるニー
ドルバルブ３５が収容されている。FIG. 8 shows the injection device of the present invention.
In the figure, reference numeral 31 indicates a storage container. An injection hole 33 is provided at one end of the storage container 31, and a needle valve 35 that can open and close the injection hole 33 is stored in the storage container 31.

【００９３】噴射孔３３には燃料通路３７が連通可能に
設けられ、この燃料通路３７は外部の燃料供給源に連結
され、燃料通路３７に常時一定の高圧で燃料が供給され
ている。従って、ニードルバルブ３５が噴射孔３３を開
放すると、燃料通路３７に供給されていた燃料が一定の
高圧で内燃機関の図示しない燃料室内に噴出されるよう
に形成されている。A fuel passage 37 is provided so as to be able to communicate with the injection hole 33. The fuel passage 37 is connected to an external fuel supply source so that fuel is always supplied to the fuel passage 37 at a constant high pressure. Therefore, when the needle valve 35 opens the injection hole 33, the fuel supplied to the fuel passage 37 is ejected at a constant high pressure into a fuel chamber (not shown) of the internal combustion engine.

【００９４】また、ニードルバルブ３５の上端部は直径
が大きくなっており、収納容器３１に形成されたシリン
ダ３９と摺動可能なピストン４１となっている。そし
て、収納容器３１内には、上記した圧電アクチュエータ
４３が収納されている。The upper end of the needle valve 35 has a large diameter, and serves as a piston 41 slidable with a cylinder 39 formed in the container 31. The piezoelectric actuator 43 described above is stored in the storage container 31.

【００９５】このような噴射装置では、圧電アクチュエ
ータ４３が電圧を印加されて伸長すると、ピストン４１
が押圧され、ニードルバルブ３５が噴射孔３３を閉塞
し、燃料の供給が停止される。また、電圧の印加が停止
されると圧電アクチュエータ４３が収縮し、皿バネ４５
がピストン４１を押し返し、噴射孔３３が燃料通路３７
と連通して燃料の噴射が行われるようになっている。In such an injection device, when the piezoelectric actuator 43 is extended by being applied with a voltage, the piston 41 is expanded.
Is pressed, the needle valve 35 closes the injection hole 33, and the supply of fuel is stopped. Further, when the voltage application is stopped, the piezoelectric actuator 43 contracts, and the disc spring 45
Pushes back the piston 41, and the injection hole 33 moves into the fuel passage 37.
Fuel injection is performed in communication with the.

【００９６】[0096]

【実施例】実施例１ まず、柱状積層体を作製した。圧電体は厚み１５０μｍ
のＰＺＴで形成し、内部電極は厚み３μｍの銀−パラジ
ウム合金によって形成し、圧電体及び内部電極の各々の
積層数は３００層とした。Example 1 First, a columnar laminate was prepared. Piezoelectric material has a thickness of 150 μm
Of PZT, the internal electrode was formed of a silver-palladium alloy having a thickness of 3 μm, and the number of laminated layers of the piezoelectric body and the internal electrode was 300 layers.

【００９７】次に、平均粒径５μｍの銀粉末を６０体積
％と、残部が平均粒径５μｍのケイ素を主成分とし、ア
ルミニウムを含む軟化点が７５０℃の硼珪酸ガラス粉末
４０体積％との混合物にバインダーを加え、十分に混合
して、銀ガラス導電性ペーストを作製し、図３（ａ）に
示すように、前記柱状積層体の側面に該銀ガラス導電性
ペーストを塗布し、８００℃で焼き付け、図３（ｂ）に
示すように、柱状積層体の側面に露出した内部電極の端
部に突起状導電性端子を形成するとともに、突起状導電
性端子の根元部を埋設するケイ素含有層を形成した。Next, 60% by volume of silver powder having an average particle size of 5 μm and 40% by volume of borosilicate glass powder having a balance of silicon having a mean particle size of 5 μm as a main component and containing aluminum and having a softening point of 750 ° C. A binder is added to the mixture and sufficiently mixed to prepare a silver glass conductive paste, and the silver glass conductive paste is applied to the side surface of the columnar laminate as shown in FIG. As shown in FIG. 3B, a protruding conductive terminal is formed on the end of the internal electrode exposed on the side surface of the columnar laminated body, and a silicon-containing material for burying the root of the protruding conductive terminal is included. Layers were formed.

【００９８】この後、図３（ｃ）に示すように、突起状
導電性端子を含む内部電極の端部一層おきに、深さ１５
０μｍ、幅５０μｍの溝を形成した後、図３（ｄ）に示
すように、銀からなる厚み２５μｍの板状導電部材を、
突起状導電性端子に３０ｋＰａで押圧し９００℃で接合
した。Thereafter, as shown in FIG. 3C, a depth of 15 is provided at every other end of the internal electrode including the protruding conductive terminal.
After forming a groove having a width of 0 μm and a width of 50 μm, a plate-shaped conductive member made of silver and having a thickness of 25 μm was formed as shown in FIG.
The protrusion-shaped conductive terminal was pressed at 30 kPa and joined at 900 ° C.

【００９９】その後、溝部に絶縁体としてシリコーンゴ
ムを充填し、板状導電部材にリード線を接続した。Thereafter, the groove was filled with silicone rubber as an insulator, and the lead wire was connected to the plate-shaped conductive member.

【０１００】その後、正極及び負極の外部電極にリード
線を介して３ｋＶ／ｍｍの直流電界を１５分間印加して
分極処理を行い、図１に示すような積層型圧電アクチュ
エータを作製した。After that, a direct current electric field of 3 kV / mm was applied to the external electrodes of the positive electrode and the negative electrode through the lead wires for 15 minutes to perform polarization treatment, and a laminated piezoelectric actuator as shown in FIG. 1 was produced.

【０１０１】なお、突起状導電性端子には、銀とパラジ
ウムが分散していた。また、突起状導電性端子の形成さ
れた柱状積層体の表面にはケイ素と鉛を含有する厚み１
０μｍのケイ素含有層（ガラス層）が形成され、前記突
起状導電性端子の根元部にはケイ素含有層の***部が形
成されていた。また、このときの突起状導電性端子の積
層方向と同一方向の幅Ｂは１０μｍ、高さｈは平均で２
０μｍで、高さバラツキは２μｍであった。なお、ケイ
素含有層の厚みｄは、Ｘ線回折測定においてＳｉ元素が
実質的に存在しなくなる部分からの厚みとして算出し
た。Silver and palladium were dispersed in the protruding conductive terminals. In addition, the surface of the columnar laminated body on which the protruding conductive terminals are formed contains silicon and lead and has a thickness of 1
A silicon-containing layer (glass layer) having a thickness of 0 μm was formed, and a raised portion of the silicon-containing layer was formed at the root of the protruding conductive terminal. In this case, the width B of the protruding conductive terminals in the same direction as the stacking direction is 10 μm, and the height h is 2 on average.
The height variation was 0 μm and the height variation was 2 μm. The thickness d of the silicon-containing layer was calculated as the thickness from the portion where Si element is substantially absent in the X-ray diffraction measurement.

【０１０２】また、各突起状導電性端子と板状導電部材
からなる外部電極とは、突起状導電性端子の先端長さの
８５％以上で接合されていた。この接合割合は、突起状
導電性端子から外部電極を剥離し、接合していた部分と
接合していない部分の長さ比で算出した。Further, each protruding conductive terminal and the external electrode made of a plate-shaped conductive member were joined at 85% or more of the tip length of the protruding conductive terminal. This bonding ratio was calculated by the length ratio of the part that was bonded and the part that was not bonded after the external electrode was peeled off from the protruding conductive terminal.

【０１０３】得られた積層型圧電アクチュエータに１５
０Ｖの直流電圧を印加した結果、積層方向に４０μｍの
変位量が得られた。さらに、このアクチュエータに室温
で０〜＋１５０Ｖの交流電圧を１２０Ｈｚの周波数にて
印加し駆動試験を行った結果、１×１０9サイクルまで
駆動したところ４０μｍの変位量が得られ、外部電極の
異常は見られなかった。表１のサンプルＮｏ．１に記載
する。 実施例２ 次に、突起状導電性端子の幅Ｂと高さｈ及び板状導電部
材の厚みｔを表１に示すように変化させた以外は、実施
例１と同様の構成の積層型圧電アクチュエータ（サンプ
ルＮｏ．２〜Ｎｏ．７）を作製した。なお、サンプルＮ
ｏ．８は銀を分散させたガラスペーストを塗布し、熱処
理して外部電極を形成したものである。The obtained laminated piezoelectric actuator has 15
As a result of applying a DC voltage of 0 V, a displacement amount of 40 μm was obtained in the stacking direction. Further, as a result of performing a drive test by applying an AC voltage of 0 to +150 V at a frequency of 120 Hz to this actuator at a frequency of 120 Hz, a displacement amount of 40 μm was obtained when the actuator was driven up to 1 × 10 9 cycles. I couldn't see it. Sample No. of Table 1 It is described in 1. Example 2 Next, a laminated piezoelectric element having the same configuration as in Example 1 except that the width B and height h of the protruding conductive terminal and the thickness t of the plate-shaped conductive member were changed as shown in Table 1. Actuators (Samples No. 2 to No. 7) were produced. Sample N
o. In No. 8, a glass paste in which silver is dispersed is applied and heat-treated to form an external electrode.

【０１０４】得られた積層型圧電アクチュエータに室温
で１５０Ｖの交流電圧を１２０Ｈｚの周波数にて印加
し、駆動試験を行った。初期に得られた変位量はすべて
のサンプル（Ｎｏ．１〜８）において４０μｍであっ
た。得られた結果を表１に示す。An AC voltage of 150 V was applied to the obtained laminated piezoelectric actuator at room temperature at a frequency of 120 Hz, and a drive test was conducted. The amount of displacement initially obtained was 40 μm in all the samples (No. 1 to 8). The results obtained are shown in Table 1.

【０１０５】[0105]

【表１】 [Table 1]

【０１０６】サンプルＮｏ．８の銀ガラスにて外部電極
を形成したサンプル以外の全てのサンプルにおいて、１
×１０8サイクルまで駆動したところ４０μｍの変位が
得られ、外部電極の異常は見られなかった。外部電極を
銀ガラスにて形成したサンプルＮｏ．８の場合、銀ガラ
スでできた外部電極がアクチュエータの伸縮に追従でき
ずに、外部電極と内部電極の間に剥離が生じ、短時間の
間に外部電極がスパークしてしまった。一方、突起状導
電性端子と板状導電部材からなる外部電極を形成したサ
ンプルＮｏ．１〜７の場合においては、１×１０8サイ
クルまで駆動しても、突起状導電性端子がアクチュエー
タの伸縮に追従できるため、外部電極に破損等の異常は
見られなかった。Sample No. 1 in all samples other than the sample in which the external electrode was formed of silver glass of 8
When driven up to × 10 8 cycles, a displacement of 40 μm was obtained, and no abnormality of the external electrode was observed. Sample No. in which the external electrode was formed of silver glass. In the case of No. 8, the external electrode made of silver glass could not follow the expansion and contraction of the actuator, peeling occurred between the external electrode and the internal electrode, and the external electrode was sparked in a short time. On the other hand, Sample No. 1 having an external electrode composed of a protruding conductive terminal and a plate-shaped conductive member was formed. In the cases of Nos. 1 to 7, no abnormality such as breakage was observed in the external electrodes because the protruding conductive terminals could follow the expansion and contraction of the actuator even after driving up to 1 × 10 8 cycles.

【０１０７】さらに駆動を継続したところ、突起状導電
性端子の幅を７５μｍ以下、高さｈを７．５μｍ以上、
板状導電部材の厚みｔを５０μｍ以下としたサンプルＮ
ｏ．１、２、３、６は外部電極と内部電極の接合部の抵
抗が十分低く且つ、アクチュエータの伸縮によって生じ
る応力を十分に吸収することができるため、高速で１×
１０9サイクル連続駆動した場合においても変位量はほ
とんど減少することなく、また、外部電極に異常は見ら
れなかった。 実施例３ 次に、板状導電部材の外部に表２に示す導電性補助部材
を設けた以外は実施例１と同様の構成の積層型圧電アク
チュエータを作製した。なおサンプルＮｏ．１は実施例
１のサンプルを示す。When the driving was further continued, the width of the protruding conductive terminals was 75 μm or less, the height h was 7.5 μm or more,
Sample N in which the thickness t of the plate-shaped conductive member is 50 μm or less
o. Since Nos. 1, 2, 3, and 6 have sufficiently low resistance at the joint between the external electrode and the internal electrode and can sufficiently absorb the stress generated by the expansion and contraction of the actuator, 1 × at high speed.
Even when continuously driven for 10 9 cycles, the displacement was hardly reduced, and no abnormality was found in the external electrodes. Example 3 Next, a laminated piezoelectric actuator having the same configuration as in Example 1 was prepared except that the conductive auxiliary member shown in Table 2 was provided outside the plate-shaped conductive member. Sample No. 1 shows the sample of Example 1.

【０１０８】得られた積層型圧電アクチュエータに室温
で１５０Ｖの交流電圧を１２０Ｈｚの周波数にて印加
し、駆動試験を行った。初期に得られた変位量はすべて
のサンプル（Ｎｏ．１、９〜１２）において４０μｍで
あった。また、同条件で１×１０9サイクルまで駆動試
験を行ったところ、すべてのサンプル（Ｎｏ．１、９〜
１２）において異常は見られなかった。An AC voltage of 150 V was applied to the obtained laminated piezoelectric actuator at room temperature at a frequency of 120 Hz, and a drive test was conducted. The amount of displacement initially obtained was 40 μm in all the samples (No. 1, 9 to 12). Further, when a drive test was conducted up to 1 × 10 9 cycles under the same conditions, all samples (No. 1, 9 to
No abnormality was found in 12).

【０１０９】次に、更に厳しい条件での駆動を行うた
め、室温で２００Ｖの交流電圧を２４０Ｈｚの周波数に
て印加し、駆動試験を行った。結果を表２に示す。Next, in order to perform driving under more severe conditions, an AC voltage of 200 V was applied at a frequency of 240 Hz at room temperature, and a drive test was conducted. The results are shown in Table 2.

【０１１０】[0110]

【表２】 [Table 2]

【０１１１】この表２から、サンプルＮｏ．１はアクチ
ュエータを高速で駆動させる場合に投入される大きな電
流に対して、外部電極が局所発熱を起こし、外部電極内
部の一部で断線が生じ、変位量が減少してしまってい
る。From Table 2, sample No. In No. 1, the external electrode locally generates heat in response to a large current that is applied when the actuator is driven at high speed, disconnection occurs at a part inside the external electrode, and the displacement amount is reduced.

【０１１２】一方、外部電極の外側に導電性補助部材が
形成してあるサンプルＮｏ．９〜１１は、アクチュエー
タに大電流を投入し、高速で連続駆動させる場合におい
ても、外部電極の抵抗が十分に低いため、外部電極内で
局所発熱を起こしたり、外部電極が断線したりすること
ないため、１×１０9サイクルまで駆動しても異常は見
られなかった。 実施例４ 次に、突起状導電性端子の形成に用いる銀ガラスペース
ト中の銀粉末とガラス粉末の混合比及びガラスの軟化
点、及び該銀ガラスペーストの塗布量を変化させる以外
は、上記実施例１と同様にして、ケイ素含有層の厚み
ｄ、突起状導電性端子の高さｈ、***部のケイ素含有層
からの高さを変えた圧電アクチュエータを作製し、表３
に記載した。尚、各突起状導電性端子と板状導電部材と
は、突起状導電性端子の先端長さの８５％以上で接合さ
れていた。On the other hand, Sample No. 1 having a conductive auxiliary member formed on the outside of the external electrode. Nos. 9 to 11 cause local heat generation in the external electrode or disconnection of the external electrode even when a large current is applied to the actuator and continuously driven at high speed, because the resistance of the external electrode is sufficiently low. Since it was not present, no abnormality was observed even after driving up to 1 × 10 9 cycles. Example 4 Next, except that the mixing ratio of the silver powder and the glass powder in the silver glass paste used for forming the protruding conductive terminal, the softening point of the glass, and the coating amount of the silver glass paste were changed, Piezoelectric actuators were manufactured in the same manner as in Example 1 except that the thickness d of the silicon-containing layer, the height h of the protruding conductive terminal, and the height of the raised portion from the silicon-containing layer were changed.
Described in. The protruding conductive terminals and the plate-shaped conductive member were joined together at 85% or more of the tip length of the protruding conductive terminals.

【０１１３】得られた積層型圧電アクチュエータに室温
で０〜＋１５０Ｖの交流電圧を１２０Ｈｚの周波数にて
印加し駆動試験を行った。得られた結果を図９に示す。An AC voltage of 0 to +150 V was applied to the obtained laminated piezoelectric actuator at room temperature at a frequency of 120 Hz, and a drive test was conducted. The obtained results are shown in FIG.

【０１１４】[0114]

【表３】 [Table 3]

【０１１５】図９から、ケイ素含有層の厚みｄが２〜１
００μｍの試料では、高速で連続駆動させた場合でも、
内部電極と外部電極の間で断線したり、スパークしたり
するといった問題が生じることなく、高信頼性を備えて
いることが判る。From FIG. 9, the thickness d of the silicon-containing layer is 2-1.
With a sample of 00 μm, even when continuously driven at high speed,
It can be seen that there is no problem such as disconnection or sparking between the internal electrode and the external electrode, and high reliability is provided.

【０１１６】[0116]

【発明の効果】本発明の積層型圧電素子によれば、内部
電極の端部に一層おきに柱状積層体の側面から突出する
突起状導電性端子を設け、該突起状導電性端子と、板状
導電部材からなる外部電極とを接合したので、積層型圧
電素子の伸縮によって生じる応力を十分に吸収すること
ができ、外部電極と内部電極の間の接点不良や、外部電
極が断線するといった問題を防ぐことができ、高信頼性
を備えた積層型圧電素子を提供することができる。According to the laminated piezoelectric element of the present invention, the protruding conductive terminals projecting from the side surface of the columnar laminated body are provided at the end portions of the internal electrodes every other layer, and the protruding conductive terminals and the plate are provided. Since the external electrode made of a conductive member is joined, the stress generated by the expansion and contraction of the laminated piezoelectric element can be sufficiently absorbed, and there are problems such as contact failure between the external electrode and the internal electrode and disconnection of the external electrode. Therefore, it is possible to provide a multilayer piezoelectric element having high reliability.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の積層型圧電素子を示すもので、（ａ）
は斜視図、（ｂ）は（ａ）のＡ−Ａ’線に沿った縦断面
図、（ｃ）は（ａ）の一部を拡大して示す斜視図、
（ｄ）は（ｂ）の一部を拡大して示す断面図である。FIG. 1 is a view showing a laminated piezoelectric element of the present invention, (a)
Is a perspective view, (b) is a longitudinal sectional view taken along the line AA 'of (a), (c) is a perspective view showing a part of (a) in an enlarged manner,
(D) is sectional drawing which expands and shows a part of (b).

【図２】突起状導電性端子の先端部と板状導電部材との
接合状態を説明するための図１（ｃ）のＢ−Ｂ’線に沿
った断面図である。FIG. 2 is a cross-sectional view taken along the line BB ′ of FIG. 1 (c) for explaining the joining state between the tip end portion of the protruding conductive terminal and the plate-shaped conductive member.

【図３】本発明の積層型圧電素子の製造方法を示す概略
図である。FIG. 3 is a schematic view showing a method of manufacturing a laminated piezoelectric element of the present invention.

【図４】板状導電部材に凹溝を形成した積層型圧電アク
チュエータを示すもので、（ａ）は斜視図、（ｂ）は
（ａ）のＡ−Ａ線に沿った縦断面図である。4A and 4B show a laminated piezoelectric actuator in which a groove is formed in a plate-shaped conductive member, wherein FIG. 4A is a perspective view and FIG. 4B is a vertical cross-sectional view taken along the line AA of FIG. .

【図５】板状導電部材にスリットを形成した積層型圧電
アクチュエータを示すもので、（ａ）は斜視図、（ｂ）
は（ａ）のＡ−Ａ線に沿った縦断面図である。5A and 5B show a laminated piezoelectric actuator in which a slit is formed in a plate-shaped conductive member, FIG. 5A is a perspective view, and FIG.
FIG. 4A is a vertical sectional view taken along line AA of FIG.

【図６】導電性補助部材を形成した積層型圧電素子を示
すもので、（ａ）は斜視図、（ｂ）は（ａ）のＡ−Ａ’
線に沿った断面図である。6A and 6B show a laminated piezoelectric element in which a conductive auxiliary member is formed, wherein FIG. 6A is a perspective view, and FIG. 6B is AA ′ of FIG.
It is sectional drawing which followed the line.

【図７】（ａ）はコイル状の導電性補助部材、（ｂ）は
波板状の導電性補助部材、（ｃ）はウール状の導電性補
助部材を用いた場合の本発明の積層型圧電素子の縦断面
図である。FIG. 7 (a) is a coil-shaped conductive auxiliary member, FIG. 7 (b) is a corrugated conductive auxiliary member, and FIG. 7 (c) is a laminated type of the present invention when a wool-shaped conductive auxiliary member is used. It is a longitudinal cross-sectional view of a piezoelectric element.

【図８】本発明の噴射装置を示す説明図である。FIG. 8 is an explanatory view showing an injection device of the present invention.

【図９】実施例４の駆動試験の結果を示すグラフであ
る。FIG. 9 is a graph showing the results of a drive test of Example 4.

【図１０】従来の積層型圧電アクチュエータの縦断面図
である。FIG. 10 is a vertical sectional view of a conventional laminated piezoelectric actuator.

【符号の説明】[Explanation of symbols]

１・・・圧電体 １ａ・・・柱状積層体 ２・・・内部電極 ４・・・外部電極 ４ａ・・・板状導電部材 ４ｂ・・・導電性樹脂 ５・・・突起状導電性端子 ５ａ・・・根元部 ７・・・導電性補助部材 ７ａ・・・導電性接着剤 ７ｂ・・・導電性コイル ７ｃ・・・導電性波板 ７ｄ・・・導電性繊維集合体 １０・・・ケイ素含有層 １０ａ・・・***部 １１・・・凹溝 １３・・・スリット ３１・・・収納容器 ３３・・・噴射孔 ３５・・・バルブ ４３・・・圧電アクチュエータ 1 ... Piezoelectric body 1a: Columnar laminated body 2 ... internal electrodes 4 ... External electrode 4a: plate-shaped conductive member 4b ... Conductive resin 5: protruding conductive terminal 5a ... Root 7 ... Conductive auxiliary member 7a ... Conductive adhesive 7b ... Conductive coil 7c ... Conductive corrugated plate 7d ... Conductive fiber assembly 10 ... Silicon-containing layer 10a ... Protuberance 11 ... Concave groove 13 ... Slit 31 ... Storage container 33 ... Injection hole 35 ... Valve 43 ... Piezoelectric actuator

Claims (15)

【特許請求の範囲】[Claims] 【請求項１】複数の圧電体と複数の内部電極とを交互に
積層してなる柱状積層体と、該柱状積層体の側面に設け
られ、前記内部電極が一層おきに交互に接続された一対
の外部電極とを具備してなる積層型圧電素子であって、
前記内部電極の端部に一層おきに前記柱状積層体の側面
から突出する突起状導電性端子を設け、該突起状導電性
端子と、板状導電部材からなる外部電極とを接合してな
ることを特徴とする積層型圧電素子。1. A columnar laminated body formed by alternately laminating a plurality of piezoelectric bodies and a plurality of internal electrodes, and a pair provided on the side surface of the columnar laminated body, wherein the internal electrodes are alternately connected to every other layer. A multilayer piezoelectric element comprising an external electrode of
Protruding conductive terminals protruding from the side surface of the columnar laminated body are provided at every other end of the internal electrode, and the protruding conductive terminals are joined to the external electrodes made of a plate-shaped conductive member. A laminated piezoelectric element characterized by: 【請求項２】突起状導電性端子の根元部が、柱状積層体
の側面に形成されたケイ素含有層に埋設されていること
を特徴とする請求項１記載の積層型圧電素子。2. The laminated piezoelectric element according to claim 1, wherein a root portion of the protruding conductive terminal is embedded in a silicon-containing layer formed on a side surface of the columnar laminated body. 【請求項３】ケイ素含有層の厚みが２〜１００μｍであ
ることを特徴とする請求項１又は２記載の積層型圧電素
子。3. The multilayer piezoelectric element according to claim 1, wherein the silicon-containing layer has a thickness of 2 to 100 μm. 【請求項４】突起状導電性端子の周りにケイ素含有層の
***部が形成されていることを特徴とする請求項１乃至
３のうちいずれかに記載の積層型圧電素子。4. The laminated piezoelectric element according to claim 1, wherein a raised portion of the silicon-containing layer is formed around the protruding conductive terminal. 【請求項５】各突起状導電性端子と外部電極とが、前記
突起状導電性端子の先端長さの５０％以上の部分で接合
していることを特徴とする請求項１乃至４のうちいずれ
かに記載の積層型圧電素子。5. The projecting conductive terminal and the external electrode are joined together at a portion of 50% or more of the tip length of the projecting conductive terminal. The laminated piezoelectric element according to any one of claims. 【請求項６】板状導電部材の厚みが５０μｍ以下である
ことを特徴とする請求項１乃至５のうちいずれかに記載
の積層型圧電素子。6. The laminated piezoelectric element according to claim 1, wherein the thickness of the plate-shaped conductive member is 50 μm or less. 【請求項７】突起状導電性端子間における板状導電部材
に、スリット又は凹溝が形成されていることを特徴とす
る請求項１乃至６のうちいずれかに記載の積層型圧電素
子。7. The laminated piezoelectric element according to claim 1, wherein a slit or a groove is formed in the plate-shaped conductive member between the protruding conductive terminals. 【請求項８】板状導電部材と柱状積層体の側面との間に
導電性樹脂が充填されていることを特徴とする請求項１
乃至７のうちいずれかに記載の積層型圧電素子。8. A conductive resin is filled between the plate-shaped conductive member and the side surface of the columnar laminated body.
8. The laminated piezoelectric element according to any one of 1 to 7. 【請求項９】板状導電部材の外面に導電性補助部材が設
けられていることを特徴とする請求項１乃至８のうちい
ずれかに記載の積層型圧電素子。9. The laminated piezoelectric element according to claim 1, wherein a conductive auxiliary member is provided on the outer surface of the plate-shaped conductive member. 【請求項１０】導電性補助部材が、導電性接着剤、導電
性コイル、導電性波板、導電性繊維集合体のうち少なく
とも１種からなることを特徴とする請求項９記載の積層
型圧電素子。10. The laminated piezoelectric material according to claim 9, wherein the conductive auxiliary member is made of at least one of a conductive adhesive, a conductive coil, a conductive corrugated sheet and a conductive fiber aggregate. element. 【請求項１１】突起状導電性端子と板状導電部材が銀を
主成分とすることを特徴とする請求項１乃至１０のうち
いずれかに記載の積層型圧電素子。11. The laminated piezoelectric element according to claim 1, wherein the protrusion-shaped conductive terminal and the plate-shaped conductive member contain silver as a main component. 【請求項１２】複数の圧電体と複数の内部電極とを交互
に積層してなり、前記内部電極の端部が側面に露出した
柱状積層体を作製する工程と、該柱状積層体の側面に、
導電性金属粉末５０〜８０体積％とケイ素を主成分とす
るガラス粉末２０〜５０体積％とからなる固形成分を含
有する導電性ペーストを塗布する工程と、該柱状積層体
の側面に塗布された導電性ペーストを加熱し、前記内部
電極の端部に前記柱状積層体の側面から突出する突起状
導電性端子を形成する工程と、該突起状導電性端子の先
端部に板状導電部材からなる外部電極を接続する工程と
を具備することを特徴とする積層型圧電素子の製法。12. A step of producing a columnar laminate in which a plurality of piezoelectric bodies and a plurality of internal electrodes are alternately laminated, and the end portions of the internal electrodes are exposed on the side surfaces, and a step of forming the columnar laminate on the side surfaces. ,
A step of applying a conductive paste containing a solid component consisting of 50 to 80% by volume of a conductive metal powder and 20 to 50% by volume of a glass powder containing silicon as a main component, and a step of applying to the side surface of the columnar laminate. A step of heating a conductive paste to form projecting conductive terminals projecting from the side surface of the columnar laminated body at the ends of the internal electrodes; and a plate-shaped conductive member at the tip of the projecting conductive terminals. And a step of connecting an external electrode. 【請求項１３】導電性ペーストを加熱して形成された突
起状導電性端子の高さバラツキが、前記突起状導電性端
子の平均高さの０．３倍以下であることを特徴とする請
求項１２記載の積層型圧電素子の製法。13. The height variation of the protruding conductive terminals formed by heating the conductive paste is not more than 0.3 times the average height of the protruding conductive terminals. Item 13. A method for manufacturing a laminated piezoelectric element according to item 12. 【請求項１４】複数の圧電体と複数の内部電極とを交互
に積層してなり、前記内部電極の端部が側面に露出した
柱状積層体を作製する工程と、該柱状積層体の側面と板
状導電部材からなる外部電極との間であって、一層おき
の露出した内部電極の端部及びその近傍の圧電体表面を
被覆するように、導電性金属粉末５０〜８０体積％とケ
イ素を主成分とするガラス粉末２０〜５０体積％とから
なる固形成分を含有する導電性ペーストを介在させる工
程と、該導電性ペーストを加熱して、前記内部電極の端
部に一層おきに前記柱状積層体の側面から突出する突起
状導電性端子を形成するとともに、該突起状導電性端子
の先端部に前記外部電極を接合する工程とを具備するこ
とを特徴とする積層型圧電素子の製法。14. A step of producing a columnar laminated body in which a plurality of piezoelectric bodies and a plurality of internal electrodes are alternately laminated, and an end portion of the internal electrode is exposed on a side surface, and a side surface of the columnar laminated body. Between the external electrodes made of a plate-shaped conductive member, 50 to 80% by volume of conductive metal powder and silicon are coated so as to cover the exposed end portions of the internal electrodes and the piezoelectric body surface in the vicinity thereof. The step of interposing a conductive paste containing a solid component consisting of 20 to 50% by volume of glass powder as a main component, and heating the conductive paste to form the columnar stacks at every other end at the end of the internal electrode. And a step of forming a protruding conductive terminal projecting from a side surface of the body and bonding the external electrode to a tip end portion of the protruding conductive terminal. 【請求項１５】噴射孔を有する収納容器と、該収納容器
内に収容された請求項１乃至１１のうちいずれかに記載
の積層型圧電素子と、該積層型圧電素子の駆動により前
記噴射孔から液体を噴出させるバルブとを具備してなる
ことを特徴とする噴射装置。15. An accommodating container having an ejection hole, the laminated piezoelectric element according to claim 1 accommodated in the accommodating container, and the ejection hole by driving the laminated piezoelectric element. An injection device comprising a valve for ejecting liquid from the injection device.
JP2002050252A 2001-02-27 2002-02-26 LAMINATED PIEZOELECTRIC ELEMENT, ITS MANUFACTURING METHOD, AND INJECTION DEVICE Expired - Lifetime JP3667289B2 (en)

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JP2015103744A (en) * 2013-11-27 2015-06-04 京セラ株式会社 Laminated piezoelectric element, and fuel injection device and fuel injection system including the same

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