EP1292995A1 - Piezo-electric bending transducer - Google Patents
Piezo-electric bending transducerInfo
- Publication number
- EP1292995A1 EP1292995A1 EP01951401A EP01951401A EP1292995A1 EP 1292995 A1 EP1292995 A1 EP 1292995A1 EP 01951401 A EP01951401 A EP 01951401A EP 01951401 A EP01951401 A EP 01951401A EP 1292995 A1 EP1292995 A1 EP 1292995A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- carrier
- bending transducer
- glass
- piezoceramic
- fibers
- 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- Withdrawn
Links
- 238000005452 bending Methods 0.000 title claims abstract description 27
- 239000011521 glass Substances 0.000 claims abstract description 22
- 239000000835 fiber Substances 0.000 claims abstract description 17
- 229920003235 aromatic polyamide Polymers 0.000 claims abstract description 9
- 239000003822 epoxy resin Substances 0.000 claims abstract description 8
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 8
- 229920001187 thermosetting polymer Polymers 0.000 claims description 9
- 239000004760 aramid Substances 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 4
- 241000531908 Aramides Species 0.000 abstract description 7
- 239000003365 glass fiber Substances 0.000 abstract description 2
- 238000005524 ceramic coating Methods 0.000 abstract 1
- 239000002131 composite material Substances 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 229920006231 aramid fiber Polymers 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229920000271 Kevlar® Polymers 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 229920000561 Twaron Polymers 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000004761 kevlar Substances 0.000 description 1
- 239000011224 oxide ceramic Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 239000004762 twaron Substances 0.000 description 1
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
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
- H10N30/2041—Beam type
- H10N30/2042—Cantilevers, i.e. having one fixed end
-
- 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
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
Definitions
- the invention relates to a piezoelectric bending transducer with a piezoceramic applied on at least one side to a carrier.
- a piezoelectric bending transducer of the type mentioned at the outset primarily serves to exploit the indirect or reciprocal piezoelectric effect, i.e. for converting electrical into mechanical energy.
- a bending transducer There are a large number of technical applications for a bending transducer. Such applications are e.g. as a piezoelectric printhead for an inkjet printer, as a sound pick-up or generator for microphones or loudspeakers, as a sensor for acceleration or pressure measurement, as a control element in Braille lines in reading devices for the blind, in textile machines, in pneumatic valves, in writing measuring devices or in contactless devices surface measuring instruments.
- a bending transducer is built up in a layer structure.
- the piezoceramic is applied to a carrier in order to improve the mechanical stability or for the purpose of better conversion of electrical into mechanical energy.
- the piezoceramic is optionally provided on both sides with electrodes in the form of a flat covering made of a conductive material.
- the support can be provided on one or two sides with the layer sequence described.
- several layers of piezoceramics including the electrodes can also be stacked one above the other.
- the object of the invention is to provide a piezoelectric bending transducer which has a good mechanical deflection capacity, ie a high deflection with a comparatively low operating voltage.
- the carrier comprises a glass with a coefficient of thermal expansion of less than 2 ⁇ 10 6 / K and in that the coating made of the piezo ceramic is thermally bonded to the carrier.
- the carrier can either consist of the glass itself or of a thermoset reinforced by fibers from the glass.
- the wearer Since the thermal expansion coefficient of a thermoset reinforced with fibers is essentially dependent on the fibers used, the wearer has a smaller thermal expansion coefficient than the piezoceramic when using the above-mentioned glass Has thermal expansion coefficient between 4 and 6 x 10 ⁇ 6 / K. Due to the heat treatment during the thermal bonding of the coating made of the piezoceramic to the carrier, the piezoceramic remains to a certain extent pre-stressed after cooling. The distortion of the lattice structure of the piezoceramic caused by the bias acts to support polarization. The piezoceramic thermally bonded to the carrier, comprising the glass mentioned shows at the same operating voltage a higher length expansion or contraction than the piezoceramic not glued to such a carrier.
- a glass with a coefficient of thermal expansion of less than 2 x 10 _6 / K is, for example, the glass sold under the trade name "S2-Glass” by Owens Corning Advanced Materials. "S2-Glass” is a registered trademark of Owens Corning. This S2 glass shows a coefficient of thermal expansion of 1.6 x 10 -6 / K.
- any other glass, for example a quartz glass, with a coefficient of thermal expansion within the specified range is also suitable for use with the piezoelectric bending transducer.
- the carrier advantageously comprises a thermoset reinforced by fibers from the glass.
- a so-called prepreg (not yet hardened, soft, pre-impregnated blank and containing fibers) is used for the carrier.
- the prepreg is laid loosely in a suitable shape together with the piezoceramic intended for the coating.
- the prepreg wets the surfaces of the piezoceramics or the electrodes applied to them by lightly pressing and thereby glues to them. Through a final heat treatment, the prepreg finally cures irreversibly to the thermoset.
- a permanent and stable connection of the components of the bending transducer is obtained in a simple manner.
- thermoset is additionally reinforced with aramid fibers.
- the mechanical properties of the piezoelectric bending transducer are further improved by introducing the aramid fibers.
- Aramid shows a negative coefficient of thermal expansion of less than -0.5 x 10 ⁇ 6 / K. In this manner and way the bias of the piezoceramic is further increased after the manufacturing process.
- Suitable aramids are, for example, the aramid sold by DuPont under the brand name Kevlar or the aramid available from Akzo Nobel under the brand name Twaron.
- the fibers are arranged unidirectionally and extend parallel to a predetermined longitudinal direction of the carrier. This results in the thermal bonding of the
- Prepregs with the coating made of piezoceramic direct the piezoceramic in the longitudinal direction.
- the piezoceramic is therefore biased in the direction of its expansion or contraction when an electrical field is applied to the electrodes.
- the unidirectional alignment also achieves the largest elastic modulus of the wearer in the longitudinal direction. Cross effects can essentially be neglected.
- An epoxy resin is advantageously suitable as the material for the thermoset.
- An epoxy resin reinforced with fibers in the form of a prepreg can be easily and inexpensively processed into the piezoelectric bending transducer.
- the mass fraction of the epoxy resin in the carrier is between 25 and 45% by weight. This ensures that the hardness and flexibility are high enough.
- 1 shows in three dimensions the structure of a piezoelectric bending transducer
- 2 shows an enlarged view of a section through a piezoelectric bending transducer.
- FIG. 1 shows a bimorph bending transducer 1 with a carrier 2 and with a first and second coating 4, 5 made of a piezoceramic applied thereon.
- the piezoceramic is a lead zirconate titanium oxide ceramic.
- the carrier 2 is an epoxy resin reinforced with glass fibers.
- the glass of the fibers is an S2 glass from Owens Corning Advanced Materials and has a coefficient of thermal expansion of 1.6 x 10 ⁇ ⁇ / K.
- fibers made of aramid are introduced, the weight ratio being between 40:60 and 60:40 in the fiber fraction.
- An epoxy prepreg was used as the starting material for the carrier. The prepreg was thermally bonded and cured by means of heat treatment with the layers 4, 5 made of the piezoceramic.
- the bending transducer 1 also has electrical connections 6, which are each electrically connected via a solder contact to electrodes 7 and 8 arranged on the carrier 2.
- the layers 4, 5 made of the piezoceramic are provided on both sides with electrodes 9, 11 and 10, 12, respectively.
- the electrodes 7 and 8 of the carrier 2, not shown here, are not flat at the locations of the carrier 2 at which the layers 4, 5 of the piezoceramic are placed, but rather as a fabric or in the form of parallel webs.
- the not yet cured epoxy resin flows through the electrodes 7 and 8 onto the electrodes 11 and 12 and thus bonds the carrier 2 to the layers 4, 5 made of the piezoceramic via the electrodes during curing.
- the electrodes 9, 10, 11 and 12 of the layers 4, 5 of the piezoceramic are each formed as a flat covering made of a carbon polymer. Due to the lower coefficient of thermal expansion of the carrier 2 compared to the thermal expansion coefficient of the piezoceramic, the latter is prestressed during thermal bonding.
- FIG. 2 shows an enlarged representation of a section through the bending transducer 1 shown in FIG. 1.
- the layers 4, 5 made of the piezoceramic and the electrodes 9, 11 and 10, 12 applied thereon can again be seen.
- the electrodes 7, 8 applied to the carrier 2 are designed as parallel webs 13 extending in the longitudinal direction of the carrier 2.
- the fibers 14 made of glass and the fibers 15 made of aramid are unidirectional and aligned in the longitudinal direction of the carrier 2. In this way, when the prepreg is thermally bonded to the layers 4, 5 of the piezoceramic, the piezoceramic is pretensioned in the longitudinal direction of the carrier 2.
- the unidirectional orientation of the fibers 14, 15 also achieves the greatest modulus of elasticity of the carrier 2 in the longitudinal direction. Cross effects can be neglected.
Abstract
The invention relates to a piezo-electric bending transducer (1) with a support (2), comprising a glass, and with a piezo-ceramic coating (4, 5), which is thermally adhered on at least one side to the support (2). According to the invention, a glass is used which has a coefficient of thermal expansion of less than 2 x 10<-6>/K. The support (2) preferably comprises a composite consisting of glass fibers (14) and epoxy resin, which can be further reinforced by aramide fibers (15). A bending transformer (1) of this type exhibits a high mechanical deflection capability.
Description
Beschreibungdescription
Piezoelektrischer BiegewandlerPiezoelectric bending transducer
Die Erfindung bezieht sich auf einen piezoelektrischen Biegewandler mit einer auf einem Träger zumindest einseitig aufgebrachten Piezokeramik.The invention relates to a piezoelectric bending transducer with a piezoceramic applied on at least one side to a carrier.
Ein piezoelektrischer Biegewandler der eingangs genannten Art dient vorrangig zur Ausnutzung des indirekten oder reziproken piezoelektrischen Effekts, d.h. zur Umwandlung von elektrischer in mechanische Energie. Für einen Biegewandler gibt es eine Vielzahl von technischen Anwendungen. Solche Anwendungen sind z.B. als piezoelektrischer Druckkopf für einen Tinten- strahldrucker, als Schallaufnehmer oder -erzeuger für Mikrophone bzw. Lautsprecher, als Sensor für die Beschleunigungsoder Druckmessung, als Stellelement in Braille-Zeilen in Lesegeräten für Blinde, in Textilmaschinen, in Pneumatikventilen, in schreibenden Messgeräten oder in berührungslosen OberflächenmessInstrumenten.A piezoelectric bending transducer of the type mentioned at the outset primarily serves to exploit the indirect or reciprocal piezoelectric effect, i.e. for converting electrical into mechanical energy. There are a large number of technical applications for a bending transducer. Such applications are e.g. as a piezoelectric printhead for an inkjet printer, as a sound pick-up or generator for microphones or loudspeakers, as a sensor for acceleration or pressure measurement, as a control element in Braille lines in reading devices for the blind, in textile machines, in pneumatic valves, in writing measuring devices or in contactless devices surface measuring instruments.
Gemäß der EP 0 455 342 Bl und der EP 0 468 796 AI wird ein Biegewandler in einer Schichtstruktur aufgebaut. Die Piezokeramik wird dabei zur Verbesserung der mechanischen Stabilität oder zum Zwecke einer besseren Umsetzung von elektrischer in mechanische Energie auf einen Träger aufgebracht. Für die elektrische Kontaktierung wird die Piezokeramik gegebenenfalls beidseitig mit Elektroden in Form einer flächigen Belegung aus einem leitfähigen Material versehen.According to EP 0 455 342 B1 and EP 0 468 796 AI, a bending transducer is built up in a layer structure. The piezoceramic is applied to a carrier in order to improve the mechanical stability or for the purpose of better conversion of electrical into mechanical energy. For the electrical contacting, the piezoceramic is optionally provided on both sides with electrodes in the form of a flat covering made of a conductive material.
Je nach Anwendung kann der Träger ein- oder zweiseitig mit der beschriebenen Schichtabfolge versehen sein. Gemäß der DE 34 34 726 C2 können auch mehrere Lagen von Piezokeramiken einschließlich der Elektroden übereinander gestapelt sein. Je nach Anzahl der Piezokeramik-Schichten spricht man von einem mono-, bi-, tri-, etc. oder allgemein von einem multimorphen piezoelektrischen Biegewandler.
Aufgabe der Erfindung ist es, einen piezoelektrischen Biegewandler anzugeben, welcher ein gutes mechanisches Auslenkvermögen, d.h. eine hohe Auslenkung bei vergleichsweise niedriger Betriebsspannung, zeigt.Depending on the application, the support can be provided on one or two sides with the layer sequence described. According to DE 34 34 726 C2, several layers of piezoceramics including the electrodes can also be stacked one above the other. Depending on the number of piezoceramic layers, one speaks of a mono-, bi-, tri-, etc. or generally of a multimorph piezoelectric bending transducer. The object of the invention is to provide a piezoelectric bending transducer which has a good mechanical deflection capacity, ie a high deflection with a comparatively low operating voltage.
Diese Aufgabe wird für den piezoelektrischen Biegewandler erfindungsgemäß dadurch gelöst, dass der Träger ein Glas mit einem Wärmeausdehnungskoeffizienten von weniger als 2 x 10~6/K umfasst, und dass die Beschichtung aus der Piezo- keramik thermisch auf den Träger aufgeklebt ist.This object is achieved for the piezoelectric bending transducer according to the invention in that the carrier comprises a glass with a coefficient of thermal expansion of less than 2 × 10 6 / K and in that the coating made of the piezo ceramic is thermally bonded to the carrier.
Der Träger kann dabei entweder aus dem Glas selbst oder aus einem Duroplasten bestehen, welcher durch Fasern aus dem Glas verstärkt ist.The carrier can either consist of the glass itself or of a thermoset reinforced by fibers from the glass.
Umfangreiche Untersuchungen haben gezeigt, dass bei Verwendung eines derartigen Glases gegenüber einem normalen Glas, welches einen Wärmeausdehnungskoeffizienten von mehr als 5 x 10"6/K zeigt, der Biegewandler bei gleicher Betriebsspan- nung eine höhere Auslenkung zeigt. Es besteht Anlass zu derExtensive investigations have shown that when using such a glass compared to a normal glass, which shows a coefficient of thermal expansion of more than 5 x 10 "6 / K, the bending transducer shows a higher deflection at the same operating voltage. There is reason for this
Vermutung, dass das bessere Auslenkvermögen mit dem kleineren Wärmeausdehnungskoeffizienten zu tun hat.Assumption that the better deflection has to do with the smaller coefficient of thermal expansion.
Da bei einem mit Fasern verstärkten Duroplasten der Wärmeaus- dehnungskoeffizient im Wesentlichen von den verwendeten Fasern abhängig ist, weist der Träger bei Verwendung des genannten Glases einen kleineren Wärmeausdehnungskoeffizienten auf als die Piezokeramik, deren Wärmeausdehnungskoeffizient senkrecht zur Polarisationsrichtung im kurzgeschlossenen Zu- stand in der Regel einen Wärmeausdehnungskoeffizienten zwischen 4 und 6 x 10~6/K besitzt. Durch die Wärmebehandlung bei dem thermischen Verkleben der Beschichtung aus der Piezokeramik mit dem Träger bleibt damit die Piezokeramik nach dem Abkühlen gewissermaßen vorgespannt. Die durch die Vorspannung bewirkte Verzerrung der Gitterstruktur der Piezokeramik, wirkt polarisationsunterstützend. Die mit dem Träger, umfassend das genannte Glas, thermisch verklebte Piezokeramik
zeigt bei gleicher Betriebsspannung eine höhere Längenausdehnung bzw. -kontraktion als die nicht mit einem solchen Träger verklebte Piezokeramik.Since the thermal expansion coefficient of a thermoset reinforced with fibers is essentially dependent on the fibers used, the wearer has a smaller thermal expansion coefficient than the piezoceramic when using the above-mentioned glass Has thermal expansion coefficient between 4 and 6 x 10 ~ 6 / K. Due to the heat treatment during the thermal bonding of the coating made of the piezoceramic to the carrier, the piezoceramic remains to a certain extent pre-stressed after cooling. The distortion of the lattice structure of the piezoceramic caused by the bias acts to support polarization. The piezoceramic thermally bonded to the carrier, comprising the glass mentioned shows at the same operating voltage a higher length expansion or contraction than the piezoceramic not glued to such a carrier.
Ein Glas mit einem Wärmeausdehnungskoeffizienten von weniger als 2 x 10_6/K ist beispielsweise das unter dem Handelsnamen "S2-Glass" vertriebene Glas von Owens Corning Advanced Materials. "S2-Glass" ist ein eingetragenes Warenzeichen von Owens Corning. Dieses S2-Glass zeigt einen Wärmeausdehnungs- koeffizienten von 1,6 x 10-6/K. Selbstverständlich eignet sich auch jedes andere Glas, beispielsweise ein Quarzglas, mit einem Wärmeausdehnungskoeffizienten innerhalb des angegebenen Bereiches zur Verwendung für den piezoelektrischen Biegewandler.A glass with a coefficient of thermal expansion of less than 2 x 10 _6 / K is, for example, the glass sold under the trade name "S2-Glass" by Owens Corning Advanced Materials. "S2-Glass" is a registered trademark of Owens Corning. This S2 glass shows a coefficient of thermal expansion of 1.6 x 10 -6 / K. Of course, any other glass, for example a quartz glass, with a coefficient of thermal expansion within the specified range is also suitable for use with the piezoelectric bending transducer.
Vorteilhafterweise umfasst der Träger einen durch Fasern aus dem Glas verstärkten Duroplasten. Dies bietet den Vorteil einer einfachen und kostengünstigen Herstellung. Für den Träger wird hierzu ein sogenanntes Prepreg (noch nicht ausgehärte- ter, weicher, vorimprägnierter und Fasern enthaltender Rohling) verwendet. Das Prepreg wird zusammen mit der für die Beschichtung vorgesehenen Piezokeramik locker in eine geeignete Form gelegt. Durch leichtes Pressen benetzt das Prepreg die Oberflächen der Piezokeramiken bzw. der darauf aufge- brachten Elektroden und verklebt dabei damit. Durch eine abschließende Wärmebehandlung härtet schließlich das Prepreg irreversibel zu dem Duroplasten aus. Man erhält auf einfache Art und Weise eine dauerhafte und stabile Verbindung der Komponenten des Biegewandlers.The carrier advantageously comprises a thermoset reinforced by fibers from the glass. This offers the advantage of simple and inexpensive production. For this purpose, a so-called prepreg (not yet hardened, soft, pre-impregnated blank and containing fibers) is used for the carrier. The prepreg is laid loosely in a suitable shape together with the piezoceramic intended for the coating. The prepreg wets the surfaces of the piezoceramics or the electrodes applied to them by lightly pressing and thereby glues to them. Through a final heat treatment, the prepreg finally cures irreversibly to the thermoset. A permanent and stable connection of the components of the bending transducer is obtained in a simple manner.
Weiter von Vorteil ist es, wenn der Duroplast zusätzlich mit Fasern aus Aramid verstärkt ist. Neben der Erhöhung der mechanischen Festigkeit des Trägers durch Aramid werden durch die Einbringung der Fasern aus Aramid die mechanischen Eigen- schaffen des piezoelektrischen Biegewandlers weiter verbessert. Aramid zeigt nämlich einen negativen Wärmeausdehnungskoeffizienten von weniger als -0,5 x 10~6/K. Auf diese Art
und Weise wird die Vorspannung der Piezokeramik nach dem Herstellungsverfahren weiter erhöht. Geeignete Aramide sind beispielsweise das von DuPont unter dem Markennamen Kevlar vertriebene Aramid oder das von Akzo Nobel unter dem Markennamen Twaron erhältliche Aramid.It is also an advantage if the thermoset is additionally reinforced with aramid fibers. In addition to increasing the mechanical strength of the support with aramide, the mechanical properties of the piezoelectric bending transducer are further improved by introducing the aramid fibers. Aramid shows a negative coefficient of thermal expansion of less than -0.5 x 10 ~ 6 / K. In this manner and way the bias of the piezoceramic is further increased after the manufacturing process. Suitable aramids are, for example, the aramid sold by DuPont under the brand name Kevlar or the aramid available from Akzo Nobel under the brand name Twaron.
In einer weiteren vorteilhaften Ausgestaltung der Erfindung sind die Fasern unidirektional angeordnet und erstrecken sich parallel zu einer vorgegebenen Längsrichtung des Trägers. Auf diese Weise ergibt sich beim thermischen Verkleben desIn a further advantageous embodiment of the invention, the fibers are arranged unidirectionally and extend parallel to a predetermined longitudinal direction of the carrier. This results in the thermal bonding of the
Prepregs mit der Beschichtung aus Piezokeramik eine gerichtet Vorspannung der Piezokeramik in Längsrichtung. Die Piezokeramik ist also in Richtung ihrer Ausdehnung oder Kontraktion bei Anlegen eines elektrischen Feldes an die Elektroden vor- gespannt. Durch die unidirektionale Ausrichtung wird zudem das größte Elastizitätsmodul des Trägers in Längsrichtung erzielt. Quereffekte können im Wesentlichen vernachlässigt werden.Prepregs with the coating made of piezoceramic direct the piezoceramic in the longitudinal direction. The piezoceramic is therefore biased in the direction of its expansion or contraction when an electrical field is applied to the electrodes. The unidirectional alignment also achieves the largest elastic modulus of the wearer in the longitudinal direction. Cross effects can essentially be neglected.
Als Material für den Duroplasten eignet sich vorteilhafterweise ein Epoxidharz. Ein mit Fasern verstärktes Epoxidharz in Gestalt eines Prepregs lässt sich leicht und kostengünstig zu dem piezoelektrischen Biegewandler verarbeiten.An epoxy resin is advantageously suitable as the material for the thermoset. An epoxy resin reinforced with fibers in the form of a prepreg can be easily and inexpensively processed into the piezoelectric bending transducer.
Dabei ist es für die Eigenschaften des Trägers besonders von Vorteil, wenn der Masseanteil des Epoxidharzes im Träger zwischen 25 und 45 Gew.-% beträgt. Damit werden gleichzeitig eine genügend große Härte und eine genügend hohe Flexibilität erzielt .It is particularly advantageous for the properties of the carrier if the mass fraction of the epoxy resin in the carrier is between 25 and 45% by weight. This ensures that the hardness and flexibility are high enough.
Ausführungsbeispiele der Erfindung werden anhand einer Zeichnung näher erläutert. Dabei zeigt:Embodiments of the invention are explained in more detail with reference to a drawing. It shows:
FIG 1 in dreidimensionaler Darstellung den Aufbau eines piezoelektrischen Biegewandlers, und
FIG 2 in vergrößerter Darstellung einen Schnitt durch einen piezoelektrischen Biegewandler.1 shows in three dimensions the structure of a piezoelectric bending transducer, and 2 shows an enlarged view of a section through a piezoelectric bending transducer.
Gleiche Teile haben dabei gleiche Bezugszeichen.The same parts have the same reference numerals.
Figur 1 zeigt einen bimorphen Biegewandler 1 mit einem Träger 2 und mit einer darauf aufgebrachten ersten und zweiten Beschichtung 4, 5 aus einer Piezokeramik. Die Piezokeramik ist hierbei eine Blei-Zirkonat-Titan-Oxidkeramik. Der Träger 2 ist ein mit Fasern aus Glas verstärktes Epoxidharz. Das Glas der Fasern ist ein S2-Glass von Owens Corning Advanced Materials und weist einen Wärmeausdehnungskoeffizienten von 1,6 x 10~δ/K auf. Zusätzlich sind Fasern aus Aramid eingebracht, wobei das Gewichtsverhältnis zwischen 40:60 und 60:40 im Fa- seranteil beträgt. Als Ausgangsmaterial für den Träger wurde ein Epoxidharz-Prepreg verwendet. Das Prepreg wurde durch eine Wärmebehandlung mit den Schichten 4, 5 aus der Piezokeramik thermisch verklebt und ausgehärtet.FIG. 1 shows a bimorph bending transducer 1 with a carrier 2 and with a first and second coating 4, 5 made of a piezoceramic applied thereon. The piezoceramic is a lead zirconate titanium oxide ceramic. The carrier 2 is an epoxy resin reinforced with glass fibers. The glass of the fibers is an S2 glass from Owens Corning Advanced Materials and has a coefficient of thermal expansion of 1.6 x 10 ~ δ / K. In addition, fibers made of aramid are introduced, the weight ratio being between 40:60 and 60:40 in the fiber fraction. An epoxy prepreg was used as the starting material for the carrier. The prepreg was thermally bonded and cured by means of heat treatment with the layers 4, 5 made of the piezoceramic.
Der Biegewandler 1 weist weiter elektrische Anschlüsse 6 auf, welche jeweils über einen Lötkontakt mit auf dem Träger 2 angeordneten Elektroden 7 und 8 elektrisch verbunden sind. Die Schichten 4, 5 aus der Piezokeramik sind beidseitig flächig mit Elektroden 9, 11 bzw. 10, 12 versehen. Die Elektroden 7 und 8 des Trägers 2 sind, hier nicht näher dargestellt, an den Stellen des Trägers 2, an welchen die Schichten 4, 5 der Piezokeramik aufgelegt sind, nicht flächig, sondern als ein Gewebe oder in Form von parallelen Stegen ausgebildet. Bei der Wärmebehandlung des Prepregs fließt deshalb das noch nicht ausgehärtete Epoxidharz durch die Elektroden 7 und 8 auf die Elektroden 11 und 12 und verklebt damit beim Aushärten den Träger 2 über die Elektroden mit den Schichten 4, 5 aus der Piezokeramik. Die Elektroden 9, 10, 11 und 12 der Schichten 4, 5 der Piezokeramik sind jeweils als eine flä- chige Belegung aus einem Carbonpolymer ausgebildet. Aufgrund des geringeren Wärmeausdehnungskoeffizienten des Trägers 2
gegenüber dem Wärmeausdehnungskoeffizienten der Piezokeramik wird letztere beim thermischen Verkleben vorgespannt.The bending transducer 1 also has electrical connections 6, which are each electrically connected via a solder contact to electrodes 7 and 8 arranged on the carrier 2. The layers 4, 5 made of the piezoceramic are provided on both sides with electrodes 9, 11 and 10, 12, respectively. The electrodes 7 and 8 of the carrier 2, not shown here, are not flat at the locations of the carrier 2 at which the layers 4, 5 of the piezoceramic are placed, but rather as a fabric or in the form of parallel webs. During the heat treatment of the prepreg, the not yet cured epoxy resin flows through the electrodes 7 and 8 onto the electrodes 11 and 12 and thus bonds the carrier 2 to the layers 4, 5 made of the piezoceramic via the electrodes during curing. The electrodes 9, 10, 11 and 12 of the layers 4, 5 of the piezoceramic are each formed as a flat covering made of a carbon polymer. Due to the lower coefficient of thermal expansion of the carrier 2 compared to the thermal expansion coefficient of the piezoceramic, the latter is prestressed during thermal bonding.
In Figur 2 ist in einer vergrößerten Darstellung ein Schnitt durch den in Figur 1 gezeigten Biegewandler 1 dargestellt. Man erkennt wiederum die Schichten 4, 5 aus der Piezokeramik sowie die darauf aufgebrachten Elektroden 9, 11 bzw. 10, 12. Die auf dem Träger 2 aufgebrachten Elektroden 7, 8 sind als sich in Längsrichtung des Trägers 2 erstreckende parallele Stege 13 ausgebildet. Deutlich zu erkennen ist, dass die Fasern 14 aus Glas und die Fasern 15 aus Aramid unidirektional und in Längsrichtung des Trägers 2 ausgerichtet vorliegen. Auf diese Weise ergibt sich beim thermischen Verkleben des Prepregs mit den Schichten 4, 5 aus der Piezokeramik eine Vorspannung der Piezokeramik in Längsrichtung des Trägers 2. Durch die unidirektionale Ausrichtung der Fasern 14, 15 wird zudem das größte Elastizitätsmodul des Trägers 2 in Längsrichtung erzielt. Quereffekte können vernachlässigt werden.
FIG. 2 shows an enlarged representation of a section through the bending transducer 1 shown in FIG. 1. The layers 4, 5 made of the piezoceramic and the electrodes 9, 11 and 10, 12 applied thereon can again be seen. The electrodes 7, 8 applied to the carrier 2 are designed as parallel webs 13 extending in the longitudinal direction of the carrier 2. It can be clearly seen that the fibers 14 made of glass and the fibers 15 made of aramid are unidirectional and aligned in the longitudinal direction of the carrier 2. In this way, when the prepreg is thermally bonded to the layers 4, 5 of the piezoceramic, the piezoceramic is pretensioned in the longitudinal direction of the carrier 2. The unidirectional orientation of the fibers 14, 15 also achieves the greatest modulus of elasticity of the carrier 2 in the longitudinal direction. Cross effects can be neglected.
Claims
1. Piezoelektrischer Biegewandler (1) mit einem Träger (2), umfassend ein Glas, und mit einer zumindest einseitig auf dem Träger (2) thermisch aufgeklebten Beschichtung (4,5) aus einer Piezokeramik, wobei das Glas einen Wärmeausdehnungskoeffizienten von weniger als 2 x 10~6/K zeigt.1. Piezoelectric bending transducer (1) with a carrier (2), comprising a glass, and with a coating (4, 5) made of a piezoceramic that is thermally bonded to the carrier (2) on at least one side, the glass having a thermal expansion coefficient of less than 2 x 10 ~ 6 / K shows.
2. Piezoelektrischer Biegewandler (1) nach Anspruch 1, wobei der Träger (2) einen durch Fasern (14) aus dem Glas verstärkten Duroplasten umfasst.2. Piezoelectric bending transducer (1) according to claim 1, wherein the carrier (2) comprises a thermosetting material reinforced by fibers (14) from the glass.
3. Piezoelektrischer Biegewandler (1) nach Anspruch 1 oder 2, wobei der Duroplast zusätzlich mit Fasern (15) aus Aramid verstärkt ist.3. Piezoelectric bending transducer (1) according to claim 1 or 2, wherein the thermoset is additionally reinforced with fibers (15) made of aramid.
4. Piezoelektrischer Biegewandler (1) nach Anspruch 2 oder 3, bei dem sich der Träger (2) in eine Längsrichtung erstreckt und die Fasern (14, 15) unidirektional und parallel zu der Längsrichtung angeordnet sind.4. Piezoelectric bending transducer (1) according to claim 2 or 3, wherein the carrier (2) extends in a longitudinal direction and the fibers (14, 15) are arranged unidirectionally and parallel to the longitudinal direction.
5. Piezoelektrischer Biegewandler (1) nach einem der Ansprüche 2 bis 4, bei dem der Duroplast ein Epoxidharz ist.5. Piezoelectric bending transducer (1) according to one of claims 2 to 4, in which the thermosetting plastic is an epoxy resin.
6. Piezoelektrischer Biegewandler (1) nach Anspruch 8, mit einem Anteil des Epoxidharzes im Träger (2) zwischen 25 und 45 Gew.-%. 6. Piezoelectric bending transducer (1) according to claim 8, with a proportion of the epoxy resin in the carrier (2) between 25 and 45 wt .-%.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE20122677U DE20122677U1 (en) | 2000-06-21 | 2001-06-18 | Piezoelectric bending transducer |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10030397 | 2000-06-21 | ||
DE1003097 | 2000-06-21 | ||
PCT/DE2001/002250 WO2001099205A1 (en) | 2000-06-21 | 2001-06-18 | Piezo-electric bending transducer |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1292995A1 true EP1292995A1 (en) | 2003-03-19 |
Family
ID=7646411
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01951401A Withdrawn EP1292995A1 (en) | 2000-06-21 | 2001-06-18 | Piezo-electric bending transducer |
Country Status (8)
Country | Link |
---|---|
US (1) | US20040012308A1 (en) |
EP (1) | EP1292995A1 (en) |
JP (1) | JP2003536278A (en) |
KR (1) | KR20030010664A (en) |
CN (1) | CN1437771A (en) |
DE (1) | DE20122677U1 (en) |
TW (1) | TW512550B (en) |
WO (1) | WO2001099205A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4583188B2 (en) * | 2004-03-29 | 2010-11-17 | 京セラ株式会社 | Acceleration sensor |
US7394610B2 (en) * | 2005-06-28 | 2008-07-01 | Kyocera Corporation | Acceleration sensor and magnetic disk device using the same |
DE502005003241D1 (en) * | 2005-11-25 | 2008-04-24 | Festo Ag & Co | Piezoelectric bending transducer |
JP5391395B2 (en) * | 2007-10-15 | 2014-01-15 | 日立金属株式会社 | Substrate with piezoelectric thin film and piezoelectric element |
JP2012178466A (en) * | 2011-02-25 | 2012-09-13 | Wac Data Service Kk | Actuator and unit for textile machine |
DE102017118220B4 (en) * | 2017-08-10 | 2020-02-06 | Dr. Schneider Kunststoffwerke Gmbh | vibration unit |
TWI679559B (en) | 2018-02-01 | 2019-12-11 | 矽統科技股份有限公司 | Interaction method between user and stylus and stylus product |
JP7445574B2 (en) | 2020-09-25 | 2024-03-07 | 株式会社Ihiエアロスペース | Power generation functional prepreg sheet, power generation functional composite material, and manufacturing method of power generation functional prepreg sheet |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
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US84720A (en) * | 1868-12-08 | Improved metal last | ||
JPS6048112B2 (en) * | 1979-05-02 | 1985-10-25 | ソニー株式会社 | Electrical/mechanical conversion element |
CA1165860A (en) * | 1979-12-12 | 1984-04-17 | Susumu Nishigaki | Piezoelectric electro-mechanical bimorph transducer |
JPS6066882A (en) * | 1983-09-22 | 1985-04-17 | Murata Mfg Co Ltd | Piezoelectric displacement element and polarizing method thereof |
FR2567705B1 (en) * | 1984-07-13 | 1986-11-14 | Thomson Csf | PIEZOELECTRIC TRANSDUCER AND PRESSURE SENSOR USING SUCH A TRANSDUCER |
DE19520796A1 (en) * | 1995-06-07 | 1996-12-12 | Siemens Ag | Piezoelectric bending transducer |
DE29623089U1 (en) * | 1996-05-23 | 1997-12-11 | Siemens Ag | Piezoelectric element |
DE19920576C1 (en) * | 1999-05-04 | 2000-06-21 | Siemens Ag | Piezoelectric transducer used e.g. as printing head of ink jet printers has a carrier made of a duroplast reinforced with fibers having a specified heat expansion coefficient |
-
2001
- 2001-06-18 EP EP01951401A patent/EP1292995A1/en not_active Withdrawn
- 2001-06-18 CN CN01811557A patent/CN1437771A/en active Pending
- 2001-06-18 WO PCT/DE2001/002250 patent/WO2001099205A1/en not_active Application Discontinuation
- 2001-06-18 JP JP2002503955A patent/JP2003536278A/en not_active Withdrawn
- 2001-06-18 DE DE20122677U patent/DE20122677U1/en not_active Expired - Lifetime
- 2001-06-18 KR KR1020027016583A patent/KR20030010664A/en not_active Application Discontinuation
- 2001-06-18 US US10/311,934 patent/US20040012308A1/en not_active Abandoned
- 2001-06-18 TW TW090114704A patent/TW512550B/en not_active IP Right Cessation
Non-Patent Citations (1)
Title |
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See references of WO0199205A1 * |
Also Published As
Publication number | Publication date |
---|---|
CN1437771A (en) | 2003-08-20 |
US20040012308A1 (en) | 2004-01-22 |
KR20030010664A (en) | 2003-02-05 |
WO2001099205A1 (en) | 2001-12-27 |
JP2003536278A (en) | 2003-12-02 |
DE20122677U1 (en) | 2007-04-05 |
TW512550B (en) | 2002-12-01 |
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