EP2020046A1 - Activateur piézoélectrique - Google Patents

Activateur piézoélectrique

Info

Publication number
EP2020046A1
EP2020046A1 EP07729044A EP07729044A EP2020046A1 EP 2020046 A1 EP2020046 A1 EP 2020046A1 EP 07729044 A EP07729044 A EP 07729044A EP 07729044 A EP07729044 A EP 07729044A EP 2020046 A1 EP2020046 A1 EP 2020046A1
Authority
EP
European Patent Office
Prior art keywords
piezoelectric
piezoelectric actuator
actuator
plastic
actuator according
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.)
Withdrawn
Application number
EP07729044A
Other languages
German (de)
English (en)
Inventor
Patrick Mattes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP2020046A1 publication Critical patent/EP2020046A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • H10N30/883—Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings

Definitions

  • the invention relates to an at least partially encased, for example, flowed around by liquid media piezoelectric actuator according to the generic features of the main claim.
  • a piezoelectric element can be used in such a way that, by utilizing the so-called piezoelectric effect, it is possible to control the needle stroke of a valve or the like.
  • the piezoelectric element is constructed of a material having a suitable crystal structure such that upon application of an external electrical voltage, a mechanical reaction of the piezoelectric element takes place, which represents a pressure or tension in a predeterminable direction as a function of the crystal structure and the contact regions of the electrical voltage.
  • Such piezoelectric actuators are suitable, for example, for applications in which lifting movements take place under high operating forces and high clock frequencies.
  • such a piezoelectric actuator as part of a Piezoinj ector from DE 10026005 Al is known, for controlling the nozzle needle in injectors for the injection of
  • Fuel can be used in the combustion chamber of an internal combustion engine.
  • this piezoelectric actuator is a piezoelectric element as Stack constructed of a plurality of piezo-ceramic layers electrically coupled to each other, which is held by an actuator foot and an actuator head under bias between two stops.
  • Each piezoceramic layer is enclosed as a piezoelectric layer between two internal electrodes, via which an electrical voltage can be applied externally. Due to this electrical voltage, the piezoceramic layers then each carry out small strokes in the direction of the potential drop, which add up to the total stroke of the piezoactuator. This total stroke can be changed by the amount of voltage applied and can be transmitted to a mechanical actuator ,
  • These common rail injectors can be constructed so that an indirectly controlled by the piezoelectric actuator nozzle needle is present, wherein the piezoelectric actuator is directly or indirectly surrounded by the pressure of the fuel and between the nozzle needle and the piezoelectric actuator only a hydraulic coupling space is provided.
  • the piezoelectric actuator in the interior of a holding body is constructed media-resistant.
  • the piezoelectric actuator must be resistant to the different fuels as well as to changing pressures and temperatures. Furthermore, it is a safe during assembly and transport
  • the invention is based on a piezoelectric actuator with a piezoelectric element described above, which consists of a multi-layer structure of piezoelectric layers, wherein between the piezoelectric layers arranged internal electrodes in the direction of the layer structure of the piezoelectric elements are alternately acted upon with a different polarity of an electrical voltage, with an actuator foot and an actuator head and with a surrounding at least the piezoelectric layers insulation medium.
  • the surface of the piezoelectric element is advantageously provided with a first electrical insulation layer.
  • the piezoelectric actuator possibly together with its held together under axial bias Aktorfußes and actuator head with at least one layer of metallic foil wrapped and on the film and the connection points of the piezoelectric element to Actuator foot and the actuator head overlaying a layer of plastic is applied.
  • a piezoactuator which can be produced cost-effectively is formed which, as mentioned at the beginning, can be part of a piezoinjector for an injection system for fuel in an internal combustion engine, the fuel flowing around the plastic.
  • the proposed casing of the piezoelectric actuator according to the invention is extremely resistant to media and also ensures safe handling during transport and during assembly.
  • protruding ends of the metallic foil converge in an extension at least in the area of the actuator base and can thus be compressed tightly into a substantially cylindrical shape which extends axially further. It is also advantageous if in the actuator foot, a central axial bore is present, in which the converging film ends are guided in the composite.
  • the plastic which is partially elastic for the mechanical and thermal stress given here and is applied as the last layer, can easily consist of a plastic coating which is enriched with solid particles.
  • the plastic encapsulation may preferably be a plastic PA66 or the like, and the solid particles, in particular for improving the heat conduction in the plastic, may be made of metal or silicon, for example.
  • the first electrical insulation layer on the surface of the piezoelectric element is preferably an electrically insulating paint applied in a manner known per se in a thickness of approximately 100 to 200 ⁇ m.
  • the metallic foil wound thereon can be, for example, about 10 to 20 ⁇ m thick.
  • the piezoelectric actuator may have a round or rectangular cross section.
  • FIG. 1 shows a section through a jacketed piezoactuator provided with a foil and a plastic encapsulation, with an actuator head and an actuator base,
  • FIG. 2 shows a section through the piezoelectric actuator according to the figure 1 with a rectangular cross section
  • Figure 3 shows a section through a provided with a film and a plastic extrusion, jacketed piezoelectric actuator with protruding merged ends of the film in a bore of the actuator base.
  • FIG. 1 shows a piezoactuator 1 which can be used, for example, for needle stroke control in the fuel injection system in an internal combustion engine.
  • a piezoelectric element 2 is part of the piezoelectric actuator 1, which still has an actuator base 3 and an actuator head 4, usually made of steel.
  • the piezoelectric actuator 1 has a rectangular cross section, but it may, depending on the application, also have a round or otherwise adapted cross-section.
  • the piezoelectric element 2 internal electrodes are not explicitly shown here, which are contacted via, also not shown here, guided by the actuator foot 3 electrical leads and external electrodes.
  • a mechanical arrangement located axially behind the actuator head 4 can be actuated in such a way that a release of a nozzle opening of the injection system can take place in the above-mentioned application.
  • the piezoelectric actuator 1 is generally installed in a holding or injector body (not shown here), the fuel being conveyed through the interior of the injector body on the piezoactuator 1. This fuel can then be injected for example in a so-called common rail system under the rail pressure mentioned in the introduction or another predetermined pressure in the combustion chamber of an internal combustion engine, not shown here.
  • the piezoelectric actuator 1 is provided with the sheath according to the invention, in which initially the surface of the piezoelectric element 2 is provided with a first electrical insulation layer 11, which consists of an electrically insulating lacquer in a thickness of about 100 to 200 microns.
  • the piezoelectric actuator with at least one layer of a metallic foil 5, for example, with a thickness of about 10 to 20 microns wrapped, wound on the piezoelectric actuator on the piezoelectric element 2 and at least partially on the actuator base 3 and the actuator head 4 is.
  • the piezoelectric element 2 should be held together with the actuator base 3 and the actuator head 4 under axial prestressing and aligned.
  • the here preferably partially elastic plastic 6, which is applied as the last layer, can be made in a simple manner of a plastic extrusion, for example of PA66, which is enriched with solid particles, for example of metal or silicon.
  • a plastic extrusion for example of PA66
  • solid particles for example of metal or silicon.
  • FIG. 2 shows a further developed embodiment, in which the piezoelectric element 2 is almost completely wound and projecting ends 7 of the film 5 converge in the area of the actuator foot 3 and are then compacted together to form a substantially cylindrical shape, which xial extends into a bore 8 in the actuator base 3.
  • a plastic 6 is applied as Kunsstoffumspritzung. It can also be seen schematically from FIG. 2 how the actuator foot 3 rests against a holding body 10 via sealing edges 9, which is only indicated here.

Landscapes

  • Fuel-Injection Apparatus (AREA)

Abstract

La présente invention concerne un activateur piézoélectrique (1) comportant un élément piézoélectrique (2) constitué d'une structure multicouche de couches piézoélectriques, une tension électrique étant appliquée à des électrodes internes disposées entre les couches piézoélectriques dans la direction de la structure de couche de l'élément piézoélectrique (2) avec tour à tour une polarité différente. Le dispositif comprend une base d'activateur (3) et une tête d'activateur (4) et un élément isolant (5, 6) entourant au moins les couches piézoélectriques de l'élément piézoélectrique. La surface de l'élément piézoélectrique (2) comporte une première couche d'isolation électrique et l'activateur piézoélectrique (1) est entouré au moins à proximité de l'élément piézoélectrique (2) d'au moins une couche d'une feuille métallique (5). Une couche de plastique (6) est prévue sur la feuille (5) et recouvre les points de connexion de la tête (4) et de la base (3) de l'activateur.
EP07729044A 2006-05-17 2007-05-11 Activateur piézoélectrique Withdrawn EP2020046A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006022997A DE102006022997A1 (de) 2006-05-17 2006-05-17 Piezoaktor
PCT/EP2007/054592 WO2007131965A1 (fr) 2006-05-17 2007-05-11 Activateur piézoélectrique

Publications (1)

Publication Number Publication Date
EP2020046A1 true EP2020046A1 (fr) 2009-02-04

Family

ID=38255064

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07729044A Withdrawn EP2020046A1 (fr) 2006-05-17 2007-05-11 Activateur piézoélectrique

Country Status (5)

Country Link
US (1) US20090102320A1 (fr)
EP (1) EP2020046A1 (fr)
JP (1) JP2009538106A (fr)
DE (1) DE102006022997A1 (fr)
WO (1) WO2007131965A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006025820A1 (de) * 2006-04-28 2007-10-31 Daimlerchrysler Ag Piezoelektrischer Aktor mit einer Ummantelung aus einem Verbundwerkstoff
DE102006046831A1 (de) * 2006-10-02 2008-04-03 Robert Bosch Gmbh Anordnung eines Piezoaktors mit einer Isolationsschicht
DE102006051328A1 (de) 2006-10-31 2008-05-08 Robert Bosch Gmbh Piezoaktormodul oder Piezoaktor mit einem ummantelnden Schutzschichtsystem
DE102006060651A1 (de) * 2006-12-21 2008-06-26 Robert Bosch Gmbh Piezoelektrischer Aktor
DE102011055996A1 (de) * 2011-12-02 2013-06-06 Epcos Ag Piezoelektrisches Bauelement und Verfahren zur Herstellung eines piezoelektrischen Bauelements
JP7619756B2 (ja) * 2018-11-09 2025-01-22 マグネコンプ コーポレーション ラップアラウンド電極を有する圧電マイクロアクチュエータの製造方法

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19908471A1 (de) * 1999-02-26 2000-09-14 Siemens Ag Hohlzylindrische Feder
DE19940056A1 (de) * 1999-08-24 2001-03-22 Siemens Ag Dosiervorrichtung und Verfahren zur Dosierung
DE19946965B4 (de) * 1999-09-30 2006-06-01 Siemens Ag Geräuschgedämpfte Aktoreinheit mit einem Piezoelement
DE10025997A1 (de) * 2000-05-25 2001-12-06 Bosch Gmbh Robert Piezoaktor
DE10054017A1 (de) * 2000-11-01 2002-05-08 Bosch Gmbh Robert Piezoaktormodul mit Vorrichtung zur Wärmeableitung
JP2002203998A (ja) * 2000-12-28 2002-07-19 Denso Corp 圧電体素子及びその製造方法
JP2002203997A (ja) * 2000-12-28 2002-07-19 Denso Corp 圧電アクチュエータ
DE10250202A1 (de) * 2002-10-28 2004-05-13 Siemens Ag Aktor mit einer Durchführungsöffnung, die bei der Umspritzung gegen eindringenden Kunststoff abgedichtet ist
DE10350061A1 (de) * 2003-10-27 2005-05-25 Robert Bosch Gmbh Aktormodul
US7218037B2 (en) * 2005-07-26 2007-05-15 Siemens Aktiengesellschaft Method for improving the long-term stability of a piezoelectric actuator and a piezoelectric actuator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2007131965A1 *

Also Published As

Publication number Publication date
US20090102320A1 (en) 2009-04-23
WO2007131965A1 (fr) 2007-11-22
JP2009538106A (ja) 2009-10-29
DE102006022997A1 (de) 2007-11-22

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