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WO2015082399A1 - Actionneur piézo-électrique et soupape de commande équipé d'un tel actionneur piézo-électrique - Google Patents

Actionneur piézo-électrique et soupape de commande équipé d'un tel actionneur piézo-électrique Download PDF

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Publication number
WO2015082399A1
WO2015082399A1 PCT/EP2014/076100 EP2014076100W WO2015082399A1 WO 2015082399 A1 WO2015082399 A1 WO 2015082399A1 EP 2014076100 W EP2014076100 W EP 2014076100W WO 2015082399 A1 WO2015082399 A1 WO 2015082399A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
piezoelectric actuator
iia
electrode
contacting layer
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.)
Ceased
Application number
PCT/EP2014/076100
Other languages
German (de)
English (en)
Inventor
Peter Cromme
Alexander Hedrich
Joachim Dietmar Vendulet
Jan Benes
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
Priority to EP14809329.7A priority Critical patent/EP3078065A1/fr
Publication of WO2015082399A1 publication Critical patent/WO2015082399A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/872—Interconnections, e.g. connection electrodes of multilayer piezoelectric or electrostrictive devices

Definitions

  • the invention relates to a piezoelectric actuator, as it can be used for example for controlling electrically operated valves for fluid control.
  • the invention is based on a piezoelectric actuator, as it is known for example from the published patent application DE 10 2006 001 134 AI.
  • a piezoelectric actuator has a plurality of piezoactive layers, between each of which a metallic layer electrode is arranged.
  • the metallic layer electrodes are mutually guided to the surface of the piezoelectric actuator, so that they can be contacted laterally on the piezoelectric actuator.
  • This contacting layer makes electrical contact with the layer electrodes which are brought to the surface on this side of the piezoelectric actuator and can be produced from metallic materials or else from other electrically conductive materials, for example based on carbon.
  • the contacting layer is not sufficient for contacting during operation of the piezoelectric actuator, since due to the change in length of the
  • Piezoactors occur very quickly cracks in this contacting layer, so that the contacting layer is no longer electrically conductive over its entire length.
  • a so-called sieve electrode is applied to the contacting layer, for example in the form of an elastic wire mesh. It is important that this sieve electrode has a sufficient elasticity to follow the movements of the piezoelectric actuator.
  • a screen electrode should be understood to mean not only electrodes consisting of a wire mesh, but also other embodiments, for example of folded, thin sheet metal or other elastic structures which have sufficient electrical conductivity.
  • the sieve electrode is soldered over the whole area to the contacting layer, so that in the overlapping region of the sieve electrode and the contacting layer, an electrical connection of the sieve electrode to the underlying contacting layer and thus to the surface coming to the surface in this area
  • Layer electrodes consists.
  • the sieve electrode is sufficiently flexible, so that even with a crack within the contacting layer, an electrical contact is ensured in the entire overlap region of the contacting layer and the sieve electrode.
  • the voltage is finally applied by the fact that the sieve electrode is electrically connected to a supply line, so that for example via a control unit, the necessary electrical voltage can be applied to the piezoelectric actuator.
  • the sieve electrode is designed as a single layer, not only the contacting layer, but also the sieve electrode can be torn by the change in length of the piezoelectric actuator, which can likewise lead to a loss of the electrical contacting of individual layer electrodes.
  • the sieve electrode is usually designed in two layers, ie, a first layer is directly connected to the contacting layer, for example by a
  • Soldering process and a second, above Siebelage is electrically connected to the underlying Siebelage.
  • the second screen layer has due to their lack of connection to the contacting layer on a greater flexibility, so that even if the direct contact with the contacting layer first screen layer tears, an electrical connection via the second wire layer to all areas of the underlying first wire layer is possible and always all layer electrodes of the piezoelectric actuator remain electrically controllable.
  • the sieve electrodes are made relatively expensive and are made of relatively expensive materials, so that the manufacturing costs of the piezoelectric actuator are not insignificantly increased by the two-layer design of the sieve and thus the cost of the products in which such piezo actuators are installed.
  • the second wire layer increases the installation space of the piezoelectric actuator.
  • the piezoelectric actuator according to the invention has the advantage that a reliable contacting of the layer electrodes is possible in a favorable and reliable manner, without a two-layered sieve electrode is necessary.
  • the piezoelectric actuator on a plurality of parallel piezoactive layers, wherein between each two adjacent layers, a metallic layer electrode is arranged and wherein the layer electrodes are mutually guided on two side surfaces of the piezoelectric actuator.
  • the layer electrodes are contacted with an outer electrode applied to the respective side surface of the piezoelectric actuator, wherein each outer electrode has a contacting layer in the form of a has on the side surface directly applied metallic layer and beyond a sieve electrode, which is applied to the contacting layer and electrically contacted with this over the entire coverage area.
  • the contacting layer has areas which are recessed in the covering area with the sieve electrode, a recessed area being present in each outer electrode.
  • the formation of the contacting layer according to claim 1 has the following effect:
  • the elongation of the piezoelectric actuator inevitably results in cracks within the contacting layer, which can continue into the sieve electrode. However, it can only come to a tearing of the wire electrode where the contacting layer overlaps with the sieve, because only there the movement of the piezoelectric actuator via the full-surface, solid connection of the sieve and contacting layer is passed directly to the sieve.
  • the formation of recessed areas in the contacting layer results in a higher flexibilization of the sieve electrode in these areas, so that they do not tear in these recessed areas.
  • the sieve electrode is constructed in a single layer, whereby it is less expensive and thinner and thus also the piezoelectric actuator cheaper and narrower in the region of the electrodes.
  • the contacting layer has two strips extending at least substantially perpendicular to the piezoactive layers, so that a strip-shaped recessed area is formed between the two strips.
  • This embodiment is simple to implement and allows the sieve electrode to be connected in such a way that it is connected to both strips of the contacting layer and makes electrical contact with them, while it spans the intermediate, strip-shaped, recessed area.
  • the contacting layer is formed from a multiplicity of at least substantially circular surfaces, so that the recessed region is formed between the circular surfaces.
  • the sieve electrode is relatively flat on the contacting layer, so that a compact and stable construction is achieved.
  • the contacting layer has a multiplicity of parallel, oblique to the piezoactive layers
  • This strip structure is also relatively easy to apply to the piezoelectric actuator and allows stable attachment of the sieve electrode on the side surface of the piezoelectric actuator.
  • a control valve is equipped with a piezoelectric actuator for controlling a fluid flow, wherein the piezoelectric actuator is designed according to the above-mentioned features.
  • a piezoelectric actuator according to the invention is shown schematically. It shows Figure 1 in a schematic representation of a piezoelectric actuator, as he from the
  • FIG. 2 shows a cross section through a piezoelectric actuator according to the invention, wherein only the upper region of the piezoelectric actuator is shown,
  • FIGS. 3a and 3b show piezoactuators known from the prior art in a schematic side view
  • Figures 4a and 4b is a side view of a piezoelectric actuator according to the invention.
  • FIGS. 5a, 5b, 5c, 5d, 5e, 5f, 5g, and 5h show different embodiments of the contacting layer of piezoactuators according to the invention.
  • the piezoelectric actuator 1 shows a known from the prior art piezoelectric actuator 1 is shown schematically.
  • the piezoelectric actuator 1 is designed as a ceramic piezoelectric actuator and has a plurality of piezoactive layers 3, which are formed parallel to each other.
  • the piezoelectric actuator 1 is formed substantially cuboid and has an upper end face 8 and four side surfaces 9, which adjoin the upper end face 8, wherein the edges are chamfered.
  • the piezoactive layers 3 have a layer thickness of preferably approximately 100 ⁇ m, while the metallic layer electrodes 4a, 4b have a layer thickness of only a few micrometers.
  • piezoelectric actuators can be produced which have a multiplicity of piezoactive layers 3 which are penetrated by metallic layer electrodes 4a, 4b, which have a spacing of typically 100 ⁇ m. Due to the relatively short distance of the metallic layer electrodes 4a, 4b from each other, very high electric field strengths can be achieved between the individual metallic layer electrodes when a relatively moderate voltage of typically approximately 150 to 200 V is applied have a strong piezoelectric effect on the piezoactive layers 3, so that the piezoelectric actuator 1 when applying an electrical voltage increases in total in length and this stroke of the piezoelectric actuator 1 can be used to control, for example, a control valve.
  • outer electrodes 10a and outer electrodes 10b not shown on the opposite side surface 9 are disposed on the side surface 9b.
  • the outer electrodes 10a, 10b are in turn connected to electrical terminals 6, so that there is a voltage source with the electrical connections
  • FIG. 2 shows a longitudinal section through a piezoelectric actuator 1 according to the invention, wherein only the upper region of the piezoactuator 1 is shown schematically.
  • the piezoelectric actuator 1 has at its upper end a piezoelectrically inactive region in which no layer electrodes are present, and then piezoactive layers 3 thereon, each with interposed layer electrodes 4a, 4b.
  • the outer electrodes 10a, 10b, which are applied to the side surfaces 9 of the piezoelectric actuator 1, consist of a contacting layer IIa, IIb, ie a metallic layer, which is applied directly to the surface of the piezoactuator 1, and of sieve electrodes 12a, 12b, which are applied to the contacting layer IIa, IIb.
  • the sieve electrodes 12a, 12b consist of a mesh of metallic wires, which are electrically conductive and which are connected via a joining process to the underlying contacting layer IIa, IIb in the entire coverage area of the sieve electrodes 12a, 12b with the respective contacting layer IIa, IIb.
  • the contacting layer IIa, IIb takes over the electrical contacting of the layer electrodes 4a, 4b, while the electrical connections 6 are attached to the sieve electrodes 12a and 12b, so that a flexible electrical contact between the electrical terminals 6 and the contacting layer IIa, IIb and thus the layer electrodes 4a, 4b takes place.
  • FIG. 3 a shows a side view of a piezoactuator known from the prior art in a schematic representation. It's the piezoactive ones again Layers 3 and arranged therebetween layer electrodes 4 a, which are guided to the surface of the side surface 9.
  • the contacting layer IIa is designed as a rectangular metal layer, on which the sieve electrode 12a is joined over its entire surface. If now an electrical voltage is applied between the layer electrodes 4a and 4b, the piezoactuator 1 lengthens, which is shown in FIG. 3b. This leads to fine cracks within the piezoceramic of the
  • Piezoactuator 9 which can continue into the contacting layer IIa, so that the contacting layer IIa can no longer conduct the electric current over its entire length. These cracks in the contacting layer IIa can continue into the sieve electrode 12a, which then likewise has a crack 14 ', so that an electrical conduction over the entire length of the sieve electrode 12a likewise no longer takes place. If a voltage is now introduced via the electrical connection 6, essentially only the lower half of the layer electrodes 4 a shown in the figure is supplied with an electrical voltage, while the upper half of the piezoelectric actuator 1 in the figure is no longer reached by the electrical voltage, so that this area of the piezoactuator 9 becomes inactive and the total stroke of the piezoelectric actuator 1 is correspondingly reduced in this illustration. If a control valve is actuated with the aid of this piezoelectric actuator, this no longer reacts as intended and malfunctioning of this control valve may occur.
  • the contacting layer IIa is carried out in the form, for example, as shown in FIG. 4a.
  • the contacting layer IIa is essentially formed here by two parallel strips applied to the side surface 9 of the piezoactuator 1, which strips are still connected to one another by two narrow strips at the upper and lower end of the piezoactuator 1.
  • a cross section through the piezoelectric actuator 1 along the line ll is indicated, showing the position of the contacting layer.
  • FIG. 4b shows the same piezoactuator with applied sieve electrode 12a, which overlaps with the two strips of the contacting layer IIa, which is shown again in cross section along the line II in the upper region of FIG. 4b.
  • the recessed area 15 of the contacting layer is covered by the sieve electrode 12a. If the piezoactuator 1 is now electrically actuated, its length increases and, as shown in FIG. 4 a, microcracks may possibly occur within the piezoceramic which also lead to cracks 14 within the contacting layer IIa.
  • the crack may continue on the sieve electrode 12a, which, however, can only tear in the region in which it is connected to the contacting layer IIa, ie in the region of the strips which run parallel and perpendicular to the piezoactive layers.
  • the interruption of the electrical conduction by these poling cracks 14 is bridged by the region of the sieve electrode 12a covering the recessed region 15 so that, in spite of the poling cracks 14, there is an electrical connection between the sieve electrode 12a and all the layer electrodes 4a.
  • FIGS. 5a to 5h Various exemplary embodiments of the design of the contacting layers are shown in FIGS. 5a to 5h.
  • the sieve electrode 12a is indicated here only by a dashed rectangle.
  • FIG. 5a shows a very similar contacting layer as shown in FIG. 4a, in which, however, the parallel metallic strips of the contacting layer IIa are no longer connected to one another via a transverse strip.
  • the sieve electrode 12a is mounted over the metallic strips of the contacting layer IIa so that it has the contact layer IIa in the overlapping area of the contacting layer IIa and the sieve electrode 12a.
  • FIG. 5b likewise shows a similar contacting layer IIa in which three metallic strips are applied to the side face 9 of the piezoelectric actuator 1 parallel and perpendicular to the layer electrodes.
  • the operating principle is the same as that described above in FIG. 4a.
  • FIG. 5c shows a contacting layer IIa, which has essentially a tooth-shaped profile, so that triangular recessed regions 15 are formed, which establish the electrical connection to the individual piezoactive layers.
  • FIG. 5d shows a similar contacting layer as in FIG. 5c, which fulfills the same purpose.
  • FIG. 5e also shows a contacting layer in which strips run parallel to one another, but now obliquely to the layer electrodes, between which in each case the recessed areas 15 are formed.
  • FIG. 5f shows a further exemplary embodiment of the contacting layer, wherein the contacting layer IIa here is formed by a plurality of oval or approximately circular smaller metal layers, between which the recessed area 15 is formed.
  • a combination of this embodiment of the contacting layer IIa and the strip-shaped contacting layers shows the embodiment of FIG. 5g, as well as the embodiment of FIG. 5h.
  • each layer electrode 4a, 4b on the one hand has an electrical contact with a contacting layer IIa and on the other hand at this height a recessed portion 15 of the contacting layer IIa is formed, in which therefore no contacting layer is present, however, from the sieve electrode 12a , 12b is spanned.

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  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

L'invention concerne un actionneur piézo-électrique (1) comprenant une pluralité de couches piézo-électriques (3) parallèles, une électrode de couche métallique (4a; 4b) étant disposée entre deux couches (3) adjacentes. Les électrodes de couche (4a; 4b) sont alternativement guidées jusqu'à la surface latérale (9) où elles sont en contact avec une électrode extérieure (10a; 10b) montée sur une surface latérale (9) de l'actionneur piézo-électrique (1). L'électrode extérieure (10a; 10b) comporte une couche de contact (IIa; IIb) se présentant sous la forme d'une couche métallique directement appliquée sur la surface latérale (9) et une électrode d'écran (12a; 12b) montée sur la couche de contact (IIa; IIb) et électriquement en contact avec celle-ci dans toute la zone de recouvrement. La couche de contact (IIa; IIb) comporte des zones évidées dans la zone de recouvrement avec l'électrode d'écran (12a; 12b), une zone évidée (15) étant présente à hauteur de chaque électrode de couche (4a; 4b).
PCT/EP2014/076100 2013-12-04 2014-12-01 Actionneur piézo-électrique et soupape de commande équipé d'un tel actionneur piézo-électrique Ceased WO2015082399A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP14809329.7A EP3078065A1 (fr) 2013-12-04 2014-12-01 Actionneur piézo-électrique et soupape de commande équipé d'un tel actionneur piézo-électrique

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102013224839.3 2013-12-04
DE102013224839.3A DE102013224839A1 (de) 2013-12-04 2013-12-04 Piezoaktor und Steuerventil mit einem solchen Piezoaktor

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Publication Number Publication Date
WO2015082399A1 true WO2015082399A1 (fr) 2015-06-11

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EP (1) EP3078065A1 (fr)
DE (1) DE102013224839A1 (fr)
WO (1) WO2015082399A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001078158A1 (fr) * 2000-04-11 2001-10-18 Robert Bosch Gmbh Actionneur multicouche piezo-electrique
EP1204152A2 (fr) * 2000-11-06 2002-05-08 CeramTec AG Innovative Ceramic Engineering Electrodes extérieures pour actionneurs piézocéramiques multicouche
EP1239525A2 (fr) * 2001-03-06 2002-09-11 Ceram Tec Ag Innovative Ceramic Engineering Actionneurs à multicouches piézocéramiques et méthode de fabrication
DE102006001134A1 (de) 2006-01-09 2007-07-12 Robert Bosch Gmbh Piezoaktor
JP2008243924A (ja) * 2007-03-26 2008-10-09 Ngk Spark Plug Co Ltd 積層型圧電アクチュエータ素子及び積層型圧電アクチュエータ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001078158A1 (fr) * 2000-04-11 2001-10-18 Robert Bosch Gmbh Actionneur multicouche piezo-electrique
EP1204152A2 (fr) * 2000-11-06 2002-05-08 CeramTec AG Innovative Ceramic Engineering Electrodes extérieures pour actionneurs piézocéramiques multicouche
EP1239525A2 (fr) * 2001-03-06 2002-09-11 Ceram Tec Ag Innovative Ceramic Engineering Actionneurs à multicouches piézocéramiques et méthode de fabrication
DE102006001134A1 (de) 2006-01-09 2007-07-12 Robert Bosch Gmbh Piezoaktor
JP2008243924A (ja) * 2007-03-26 2008-10-09 Ngk Spark Plug Co Ltd 積層型圧電アクチュエータ素子及び積層型圧電アクチュエータ

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Publication number Publication date
DE102013224839A1 (de) 2015-06-11
EP3078065A1 (fr) 2016-10-12

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