DE102012020956A1 - Wire structure of piezo element e.g. piezoelectric actuator, has electrical conductive metallic material matrix that is formed on surface contact of piezoactive material and connected with single wires which are laterally spaced apart - Google Patents

Abstract

The wire structure (1) has a matrix (3) of electrically conductive metallic material that is formed on the surface contact of a piezoactive material and connected with the single wires (2) which are laterally spaced apart. The single wire is made of copper covered up with stainless steel. The matrix is made of tin, lead, indium or alloys. Independent claims are included for the following: (1) a manufacturing method for wire structure; (2) a manufacturing method for piezo element; and (3) a piezo element.

Description

The present invention underlying in particular relates to a Drahtgelege for a piezoelectric element, in particular a piezoelectric actuator, a manufacturing method for such Drahtgelege and a corresponding piezoelectric element.

Piezo elements, in particular piezoelectric actuators, in particular of ceramic materials, usually require surface metallization or contacting for signal generation. Previously known metallizations or contacts comprise, for example, perpendicular to the surface of the ceramic material soldered and electrically connected to each other via contact pins wires. Exemplary is on the DE 199 45 933 C1 , the DE 10 2004 005 943 A1 and the DE 10 2005 01 762 A1 directed.

Furthermore, it is in particular from the DE 10 2004 004 737 A1 It is known to use a fabric structure made of conductive material for contacting piezoactive materials, which is soldered and thus connected to the piezoactive material.

In particular, the known variants for contacting piezoactive materials of piezoelectric elements and piezoelectric actuators are comparatively complicated and definitely in need of improvement, in particular with regard to the quality of electrical conductivity and mechanical strength.

The object of the invention is to eliminate the disadvantages of the prior art. In particular, a possibility for contacting piezoelectric elements should be provided, which can be implemented comparatively easily and inexpensively, and with which, in particular, improved mechanical strengths and / or conductivities can be achieved. Furthermore, a manufacturing method for a corresponding clutch as well as a piezoelectric element and a manufacturing method for it are to be provided under analogous aspects.

This object is achieved in particular by the independent claims and additional claims. Embodiments of the invention will become apparent in particular from the dependent claims.

According to claim 1, a Drahtgelege, hereinafter also referred to as scrim, provided, which is designed for surface contacting of a piezoactive material. In that regard, the wire support is, in particular, a piezoelectric wire support which is specially designed to be electrically conductively connected to the surface of a piezoactive material, in particular a piezoactive basic body of a piezoelectric element or piezoactuator.

In its geometrical dimensions, the wire cladding can be adapted in particular to geometries of piezo elements and basic bodies thereof and / or to surfaces of the piezo elements to be contacted. Base bodies of piezoelectric elements may have, for example, dimensions in the length of up to 30 mm, and in the width and thickness of up to or less than 5 mm. The wire cladding may have corresponding dimensions.

The piezoactive material may in particular be a ceramic material. In that regard, the wire cladding may be specially designed to be electrically conductively connected to a ceramic material. It should be noted that the piezoactive material, in particular in the form of a base body, together with the surface contacting proposed herein, d. H. the Drahtgelege, generally a piezoelectric element, in particular a piezoelectric actuator, can form. Preferably, the piezoactive material is a substantially freely configurable in different geometric shapes and sizes material, so that the piezoactive material can be made in particular in the form of a mechanically solid body in different geometries and shapes.

The wire scrim according to the invention comprises a plurality, but at least two, individual wires. The individual wires of the wire mesh are laterally spaced from each other. The term lateral is to be understood here in particular as meaning a direction running transversely, in particular perpendicularly, to the longitudinal direction of the individual wires.

Preferably, the individual wires are parallel to each other, more preferably in a coplanar arrangement to each other, aligned or arranged. In particular, the longitudinal axes or longitudinal directions of the individual wires can run or be aligned substantially parallel to one another. In particular, parallel to one another, in particular, should mean that adjacent individual wires are substantially constantly spaced from each other over their length. The term "substantially" is intended to mean in the above-mentioned contexts that deviations in the parallelism and / or in the intervals in the context of production-related fluctuations.

In a coplanar arrangement of the individual wires in particular flat and flat scrim can be achieved with advantageous low heights.

If more than two individual wires are present, or are connected to a contexture, the distances of each adjacent individual wires can be substantially equal. In other words, the distances between any but adjacent individual wires in the context of approximately the same size. A scrim designed in accordance with the aforementioned variant thus comprises individual wires aligned parallel to one another and equidistantly or a composite of correspondingly arranged individual wires.

It should be noted that the distances between different adjacent individual wires may also vary and / or be different from each other. In general, it is possible to vary the density of individual wires in the lateral direction, whereby in particular the conductivity and / or tensile strength of the fabric can be varied or set in a flexible manner.

The individual wires are connected by a matrix of a metallic material, in particular a solder material, electrically conductive with each other. Preferably, the individual wires have no insulation. However, the individual wires should have no insulation, at least in the region of the matrix, but at least in a partial region of the matrix in the longitudinal direction of the individual wires. H. be free of insulation. This results in particular in an electrically conductive composite of the individual wires, in which in particular the individual wires in the metallic material, d. H. the matrix can be embedded.

The term matrix is to be understood in particular as a matrix which connects the individual wires in an electrically conductive manner, preferably without touching the individual wires, and in which the individual wires are preferably completely embedded. In that regard, the matrix can be referred to as a filling compound and compound mass enveloping the individual wires and connecting them to one another in an electrically conductive manner. On the one hand, the matrix makes it possible to produce the fabric simply by allowing the individual wires to be connected to one another in a simple manner. On the other hand, the matrix allows a simple electrical contacting of the fabric with a base body of a piezoelectric element. Both advantages can be achieved, in particular, with a matrix comprising a solder material or consisting of a solder material. Here, both the embedding of the individual individual wires in the matrix, d. H. the connection of the individual wires through the matrix, as well as the connection of the Geleges with the body by melting, liquefaction and / or partial liquefaction of the solder material done.

The term clutch is to be understood in particular as meaning that the individual wires as such are freely and substantially independently positioned with respect to the mutual arrangement. This distinguishes the context of woven and non-woven arrangements, which have a mutual entanglement and / or concatenation and thus a dependent positioning.

As has already been mentioned among others, it is particularly advantageous in the case of the wire scrim as proposed in claim 1 that it can be produced comparatively easily, and also cost-effectively. Furthermore, the contacting or electrical connection of the fabric to the piezoactive material, in particular a ceramic material, d. H. a piezo ceramic, comparatively simple, yet sufficiently strong and stable.

The particular advantage of the proposed Geleges can be seen in particular in the structure, which provided for tapping electrical signals individual wires for both mechanical and electrical networking or their arrangement in an electrically and mechanically stable composite, connected to the metallic material of the matrix, embedded in particular. With this construction, the connection of the individual wires to the piezoactive material, for example to a piezoactive main body of a piezoelectric element, can be significantly simplified. A connection of the Geleges with the main body of a piezoelectric element, for example, carried out so that the scrim is placed on the body, and the metallic matrix is melted up or down, so that it forms an electrically conductive cohesive connection with the base body.

Another advantage lies in the comparatively high flexibility with regard to relevant parameters such as conductivity and / or (longitudinal) tensile strength. The conductivity and / or tensile strength can be varied, inter alia, for example, by the number of individual wires. In addition, the clutch proposed according to the invention is scalable in a simple manner, in particular owing to the construction in terms of size and extent. Specifically, the scrim can be produced in a simple manner and without significant effort in different sizes and dimensions, in particular different lengths and widths. In this connection, it should be mentioned as a further advantage that the proposed scrim can first be produced as a band comprising the individual wires and the matrix, in particular as a continuous scrim tape. The scrim band can be considered as a precursor in the manufacturing process of a piezoelectric element, in particular piezoelectric actuator, the transport storage and further processing or by roll or spool. In particular, a single scrim may be soldered directly from the roll to the piezoactive material. Apart from that, it is easily possible to assemble loops from the band.

In one embodiment of the invention, it is provided that the melting temperature of the metallic material is so lower than the melting temperature of the individual wires, or the materials of the individual wires, that the metallic material can be melted separately from the individual wires. This allows in particular a comparatively simple contacting method. For example, it is possible to apply the scrim to the respective piezoactive material and to connect with the piezoactive material while subjecting the material to thermal energy, in particular by melting or melting only the metallic material. A temperature-induced impairment of the individual wires can be avoided due to the lower melting temperature of the metallic material, in particular a solder material, as required. By melting the metallic material, it can enter into satisfactory mechanical and electrical connections, in particular with piezoactive, ceramic materials, which usually have a comparatively high surface roughness and / or porosity.

According to one embodiment of the invention, it is provided that at least one of the individual wires has a tensile strength of at least 1000 N / mm ² , wherein the tensile strength is preferably in the range of 1300 N / mm ² to 1700 N / mm ² Such properties of the individual wires have in particular proved to be advantageous in order to withstand the expansion behavior and structural changes, in particular embrittlement, of the piezoactive material, which may be present, for example, as a piezoceramic body.

According to a further embodiment, with which in particular the aforementioned tensile strengths can be achieved, it is provided that at least one, or a subset, of the individual wires is made of a material of comparatively high tensile strength. Such a wire may in particular be made of steel or stainless steel. Also possible composite wires, which include a soul of steel or stainless steel. To improve the electrical conductivity composite wires can be coated with a core of a material of relatively high tensile strength with a material of relatively high conductivity, such as copper or a copper alloy.

Preferably, the core is made of a stainless steel material, and the jacket is preferably made of copper or a copper alloy.

In an embodiment in which, for example, some of the individual wires are designed as composite wires, a certain amount of individual wires made of copper, in particular pure copper or copper alloys, may be provided. Such individual wires have particularly advantageous, comparatively high electrical conductivities. Preferably, the number of mechanically stable individual wires, in particular composite wires and / or individual wires made of steel or stainless steel, selected such that with the scrim the required for the expansion behavior of the piezoactive material mechanical tensile strength and (longitudinal) tensile strength can be met.

For the clutch, essentially any combination of individual wires with comparatively high conductivity and individual wires with comparatively high (longitudinal) tensile strength can be used, as is apparent in particular from the above statements. Unlike the prior art, in this way, d. H. due to the possibility of heterogeneous combination of corresponding individual wires, the conductivity and (longitudinal) tensile strength of the fabric varies in a wide range and in a relatively simple manner and adapted to respective requirements.

According to one variant, at least one of the individual wires has an electrical conductivity of at least 30% to at least 35% IACS. The abbreviation IACS means the "International Annealed Copper Standard". Especially with ceramic piezo elements or actuators, the mentioned conductivities have been found to be sufficient. With the aforementioned conductivities, in particular in the range of 30% to 35%, or similar ranges, materials or combinations of materials for the individual wires come into consideration, in addition to a satisfactory conductivity and a satisfactory mechanical stability, in particular tensile strength. Because of the tensile strength, reference is made to the statements above, in particular concerning composite wires.

According to a further variant, the diameter of the single wire is in the range between 30 .mu.m and 1 mm, preferably between 30 .mu.m and 80 .mu.m, more preferably at about 60 .mu.m. Single wires with the dimensions mentioned have proven to be advantageous and also sufficient in particular for piezo elements and actuators, in particular made of ceramic materials. In particular, comparatively low overall heights can be achieved while still having sufficient electrical conductivity and (longitudinal) tensile strength. It is pointed out in this context that the total thickness of the Geleges can be adjusted or varied, inter alia, by the thickness of the individual wires. By reducing the overall thickness of the fabric, ie reducing the thickness of the wires, a reduction in the (longitudinal) tensile strength of the individual wires possibly accompanied thereby can be compensated for by increasing the number of individual wires in the fabric. Accordingly, a reduction in electrical conductivity possibly caused by the choice of thinner individual wires can be compensated for by increasing the number of individual wires.

According to a further embodiment of the invention, the matrix has a, in particular average, layer thickness or layer thickness in the range between 1 μm to 50 μm, preferably 5 μm-25 μm, more preferably about 20 μm. The layer thickness or layer thickness is to be understood in particular as the thickness of the metallic material of the matrix measured in the normal direction of the gel. If the wires are embedded in the matrix, the layer thickness may relate in particular to the thickness measured in the normal direction of the metallic material located above or on the wires and / or to the thickness of the metallic material measured in the normal direction between two individual wires. If the individual wires are completely embedded in the matrix, the layer thickness preferably refers to the thickness of the metallic material measured in the normal direction of the layer and radially to the individual wire. The stated layer thicknesses have proved to be suitable and also sufficient in particular for the contacting, in particular soldering, of the joint with the piezoactive material, in particular a piezoceramic. With the specified layer thicknesses, a connection of the individual wires provided, for example, to the signal pick-off can be achieved with the piezoactive material, which meets the requirements for electrical conductivity and mechanical strength.

In one embodiment, it is provided that the matrix, more precisely the metallic material, essentially consists of a solder material, in particular of tin or a tin alloy, or that the matrix is a solder material such as tin, lead, indium and / or alloys thereof, or the like Material, in particular as an essential component, for example in a proportion of at least 60 wt .-% comprises.

In an embodiment of the wire mesh, a mutual spacing of the wires is up to 1.5 times the respective wire diameter or the respective wire diameter or an average value of the same. On the mutual distance, which is particularly associated with the density of the wires in the matrix, in particular the (longitudinal) tensile strength of the fabric and the surface density of the individual wires and thus the electrical contact density between scrim and piezoactive material can be adjusted. The reliability of the electrical contact and the reliability can be influenced by the wire density, because with increasing surface density of individual wires, it is more likely that a, caused for example by breakage or crack of a single single wire, defect can be intercepted by adjacent individual wires. The abovementioned mutual distances have proven particularly useful for piezoceramic materials.

Overall, it results in particular from the above statements that the proposed Drahtgelege is simple and inexpensive to produce and allows a simplified and cost-effective production of piezoelectric elements. In addition to the manufacturing advantages, the proposed clutch is flexible in structure and scalable, especially in terms of dimensions, conductivity, (longitudinal) tensile strength and height.

Claim 12 is directed to use of the wire mesh, wherein the wire mesh may be formed as described above, including the mentioned embodiments and variants. Claim 12 is directed to the use of the wire mesh for producing an electrical surface contacting of a piezoactive material, in particular a piezoelectric element or actuator. The wire cladding comprises, as described above, a plurality of individual wires electrically conductively interconnected by a matrix of a metallic material. In the proposed use of the Drahtgelege the Drahtgelege is connected by a, in particular by heat application of the metallic material of the matrix caused, conductive cohesive connection with the piezoactive material. The conductive cohesive connection is preferably a solder joint, in which case in particular the metallic material of the matrix serves as the solder material.

A heat application of the metallic material, which is preferably a solder material, preferably takes place in such a way that, although the metallic material is melted or fused on, but not the individual wires. Apart from that, the application of heat should be designed such that the piezoactive material, in particular the functionality of the piezoactive material, is at least not substantially impaired.

With heat exposure of the metallic material, for example, with melting the same, this can connect to the surface of the piezoactive material, so that the individual wires are electrically connected or connected to the ceramic material. About the matrix, the individual wires are electrically connected to each other and can be used for example for signal pickup.

Because of advantages and advantageous effects of using the wire mesh reference is made to the above statements. Among other things, comparatively low overall heights, fail-safe and reliable contacts, comparatively high conductivities, as well as advantages in the production and contacting can be achieved when using the Geleges.

Claim 13 is directed to a method for producing a wire mesh, wherein the wire cladding may be formed in particular according to the above embodiments and variants.

In the manufacturing method, a plurality of individual wires are initially provided, wherein the individual wires are arranged and aligned in accordance with a predetermined pattern and, in particular laterally, from one another. In particular, the individual wires can be arranged and aligned parallel to one another and preferably coplanar with one another. Deviating from a coplanar and / or parallel alignment or arrangement, other, in particular linear, curved, meandering, uniplanar, multiplanar, etc., wire arrangements and wire courses, in particular with at least pairwise parallel individual wires, come into question. A uniplanar arrangement should be understood to mean that the individual wires are arranged essentially in a common plane, while a multiplanar arrangement is to be understood as meaning that the individual wires are arranged in, for example, two or more, different, in particular parallel, or disjoint, planes are.

After provision of the individual wires, at least the individual wires are heated in a predetermined region, in particular locally, and a solderable metallic material, in particular a solder material, is stirred in such a way that the metallic material forms a matrix through which the individual wires are electrically conductively connected to one another. Preferably, the metallic material is supplied in such a way and the heating takes place in such a way that the individual wires are or are electrically conductively connected to one another via a matrix formed from the solderable metallic material. The individual wires can be embedded in the matrix that forms, with the layer thickness or thickness of a layer surrounding the individual wires, in particular of an envelope of the individual wires, resulting inter alia from the quantity of supplied metallic material.

The heating, d. H. the supply of heat energy, preferably takes place such that the metallic material, in particular the solder material, melted, d. H. liquefied or partially liquefied is, without the individual wires melted, melted and / or in their structure, in particular in their microstructure, changed.

After forming a connection between the individual wires and the metallic material, in particular after forming the matrix connecting the individual wires, the composite, in particular the scrim, can be cooled in a cooling section, and then rolled up onto a reel or wound onto a reel.

To produce the fabric, the individual wires can be unwound, for example, from an unwinding or unwinding station and fed to a tool, by which the individual wires are arranged or positioned in accordance with the predetermined pattern, in particular spaced apart from each other. The tool may for example be designed such that the individual wires at least over a predetermined length parallel to each other, in particular coplanar parallel to each other. The correspondingly aligned individual wires can then be fed to a soldering station, in which the individual wires, in particular locally, are brought to the required soldering temperature, and in which a predetermined amount of a solder material forming the matrix is supplied, so that the individual wires are connected to one another by a solder material matrix , Subsequently, the scrim can be cooled in a cooling section. Before the soldering process, the individual wires can optionally be moistened with a flux.

The scrim can be used as a continuous band, i. H. Scrim tape to be made. The scrim tape can be wound up after completion on a roll or spool. A further processing, for example, for assembly or attachment to a piezoelectric body of a piezoelectric element can then be done by roll or coil, which can offer a production advantage.

The metallic material, in particular the solder material, can be supplied to the individual wires in a still solid state or in an already molten state. The amount of supplied metallic material is chosen in particular so that in the matrix, in particular taking into account other production parameters, the particular desired layer thicknesses can be achieved.

In the method can be used as a solderable metallic material tin, indium, lead or a tin, indium or lead alloy. In particular, soldering temperatures in the range of about 130 ° C to 350 ° C, in particular in the range of 280 ° C, are suitable for these solder materials.

According to one embodiment, the metallic material is applied in such a way, in particular fed, that its layer thickness in the range between 1 .mu.m and 50 .mu.m, preferably at about 20 microns. In particular, the supplied quantity of metallic material can be adjusted so that the corresponding layer thicknesses and / or a matrix encompassing the individual wires, in particular enclosing or enclosing, is achieved.

In an advantageous variant of the method it is provided that the individual wires are subjected to an acid treatment before the supply of the solder material, in particular before heating. By means of the acid treatment, it is possible to remove oxides which are in opposition to an optimum compound of the solder material with the individual wires. Before applying the soldering material, the individual wires can still be moistened with a flux.

Claim 16 relates to a manufacturing method for a piezoelectric element, in particular a piezoelectric actuator, wherein first made in accordance with a proposed embodiment or variant trained wire scrim and prepared and / or provided according to an embodiment or variant proposed herein wire scrim is provided. The provided wire scrim is connected to a base body of the piezoelectric element made of a piezoactive material, in particular to a soldering station, in a soldering process. The manufacturing method allows cost-effective production of piezoelectric elements, in particular piezoelectric actuators.

In a variant of the manufacturing method for piezo elements, in particular piezo actuators, it is provided that a soldering station used for the purpose of carrying out the soldering operation is fed with a scrim tape. The scrim tape comprises a plurality of serially interconnected wire scrim. For example, the scrim may be wound on a roll or spool and fed from the reel or spool to the soldering station. When using a scrim-tape, the soldering process can be performed before separation of individual wire scrim or piezo elements. In particular, a continuous piezoelectric element band can be produced from a continuous scrim band by soldering to corresponding base bodies of piezo elements.

This results, in particular, in the possibility of rewinding or winding up the piezoelectric elements, in particular piezoelectric actuators, produced from the base body and soldered scrim, so that subsequent processing steps, for example in automatic insertion machines, can take place from roll or spool.

According to a variant, it is possible that the compound, i. H. Soldering, the Geleges done with the body substantially immediately after the preparation of the Geleges, d. H. without requiring transient unwinding and unwinding of the scrim tape on roll or spool.

Claim 18 relates to a piezoelectric element, in particular a piezoelectric actuator. The piezoelectric element comprises a base body made of a piezoactive material, and further a metal matrix wire mesh formed according to any of the configurations and variants proposed herein. As described above, several individual wires are connected to one another in an electrically conductive manner through the matrix. The matrix is connected in the proposed piezoelectric element by a conductive cohesive connection with the surface of the body. The conductive cohesive connection is preferably a solder joint, wherein the matrix itself advantageously comprises or consists of a solder material. With a matrix of solder material, the solder joint can be made by melting the metallic matrix. As a result of the conductive cohesive connection, in particular the individual wires of the cover are connected in an electrically conductive manner to the base body. In that regard, or is a tap or a loading of the body with electrical signals on the individual wires possible.

Advantages and advantageous effects of the wire mesh described above and the manufacturing method apply correspondingly to the piezoelectric element proposed herein. In that regard, reference is made to the above statements.

Embodiments of the invention are described below with reference to figures. Show it:

1 a sectional view of a wire mesh;

2 a perspective view of the wire mesh;

3 a piezoelectric element;

4 schematically the procedure for the production of wire mesh; and

5 by way of example, a tool that can be used in the production of the wire mesh.

1 shows a cross section through a Drahtgelege 1 , The wire scrim 1 is flat and comprises by way of example 10 (ten), spaced apart in a lateral direction and coplanar with each other arranged individual wires 2 , Furthermore, the wire cladding includes 1 a matrix 3 from a metallic material, for example, tin, indium, lead or alloys thereof. The single wires 2 are through the matrix 3 electrically connected to each other. As in the present example, the individual wires 2 into the matrix 3 be embedded. The single wires 2 form, so to speak, tracks that go into the matrix 3 are embedded.

The individual wires in the present case are composite wires with a core of a steel material, and a sheathing of a copper material. As steel material in particular stainless steel comes into question. Stainless steel souls have comparatively high longitudinal tensile strengths, which directly affects the scrim 1 transmits itself.

The sheath with a copper material, such as copper or a copper alloy, serves to improve the electrical conductivity of the individual wires, in particular to increase.

It turns out that with composite wires in particular the requirements for the strength, in particular longitudinal tensile strength, and the requirements for the overall conductivity of the Geleges 1 can be solved in a satisfactory manner.

Notwithstanding the in 1 shown solution in which the individual wires 2 the same type and have the same structure, the Drahtgelege 1 individual wires 2 have different types. For example, it is possible that the clutch 1 in addition to composite wires, in particular the above-mentioned steel-copper composite wires, and non-composite wires of a copper material, such as pure copper or a copper alloy includes. By appropriate wires, the conductivity can be improved. Possibility of a flexible combination of different types of wire properties of the Geleges, in particular (longitudinal) tensile strength and conductivity can be easily adapted to different requirements.

2 shows a perspective view of the wire mesh 1 , As you can see, the single wires are 2 of the occasion 1 into the matrix 3 embedded. The matrix 3 extends in the longitudinal direction of the individual wires 2 over a given length L, which can be adjusted substantially freely. Furthermore, the type, arrangement and relative position of the individual wires 2 be adapted substantially flexible. In this way is the Drahtgelege 1 highly scalable and accessible to a relatively broad range of applications.

In the in 2 shown embodiment protrude the individual wires 2 on the front sides of the wire mesh 1 from the matrix 3 out, so that the individual wires can be contacted electrically at the protruding ends.

At wired 1 with single wires 2 whose diameter D (see 1 ) can be in the range between 30 .mu.m and 1 mm, the layer thickness S (see 1 ) are in particular in the range between 1 .mu.m and 50 .mu.m. For the present exemplary embodiment, and in particular for the purposes of this application, the layer thickness S is determined in particular as the thickness of the matrix layer between the surface O (see FIG 1 ) of the matrix 3 and the, in 2 dotted implied, fictitious envelope E (see 1 ) of the individual wires 2 Understood.

3 shows a piezo element 4 , which the previously described Drahtgelege 1 includes as well as one with the Drahtgelege 1 connected basic body 5 of piezoactive material, which may be in particular a piezoceramic.

body 5 and wire cladding 1 , more precisely, the surface of the body 5 and the matrix 3 of the wire mesh 1 , Are connected by a conductive cohesive connection. This particular are the individual wires 2 electrically conductive with the piezoactive body 5 connected. In that regard, the individual wires 2 for signal pickup or for acting on the body 5 to be used with electrical signals.

The conductive cohesive connection preferably comprises a solder joint. The metallic material of the wire mesh preferably comprises 1 a solderable material, in particular a solder material, including the possibility that the metallic material consists of a solder material.

Because of the matrix 3 itself is a solderable, the conductive cohesive connection, in particular solder joint by heating the metallic material of the matrix 3 be made in a soldering process. In particular, tin or a tin alloy can be used as the metallic material. Any other soldering materials that are suitable for electrically connecting the individual wires embedded in the matrix to the base body are also suitable.

Another advantage of the proposed wire mesh 1 is that this by appropriate choice of the individual wires 2 and the metallic material of the matrix 3 can be trained essentially self-supporting. This allows a particularly simple handling of the wire mesh in the production of the piezoelectric element 1 , In particular, a comparatively simple positioning of the wire mesh 1 on the body 5 ,

4 schematically shows a possible procedure for the production of wire mesh 1 , More particularly, the illustrated process relates to the production of a continuous belt having longitudinally successive wire patches 1 , Single wire cladding 1 can be obtained by isolation from the clutch band.

One of several parallel and laterally spaced apart individual wires 2 existing wire package 6 becomes a soldering device 7 supplied, or in other words, a soldering device 7 comes with a single, laterally spaced apart individual wires 2 comprehensive wire package 6 fed.

A tool with a corresponding wire package 6 from a plurality of mutually parallel and laterally spaced apart individual wires 2 can be achieved is exemplary in 5 shown.

The tool comprises a plurality of parallel arranged pulleys 8th , The pulleys 8th are trained and furnished the individual wires 2 to a band of coplanar parallel and laterally spaced apart individual wires 2 redirect. This is for every single wire 2 exactly one pulley 8th intended. The mutual distances of the individual wires 2 can in particular on the distances of the pulleys to the central axis of the resulting wire package 6 be set. In addition, it can be provided that the lateral distances of the individual wires 2 through an alignment unit 9 ie a unit for alignment and positioning of the individual wires 2 , is set or fixed. The in the direction of the individual wires 2 , in 5 from left to right, resulting wire package 6 can be like in 4 be shown process supplied.

The feeding of the wire package 6 to the soldering device 7 can have one or more leadership roles 10 respectively. The soldering device 7 upstream, the wire package 6 be moistened with a flux. For this purpose, for example, a flux-impregnated felt, or a similar element may be used, which with the individual wires 2 is brought into contact and the individual wires 2 moistened with the flux.

At the soldering device 7 in particular, the wire package 6 locally heated, and that of the soldering device 7 supplied lot 11 liquefied. The liquefied lot 11 gets the wire package 6 supplied in such a way that the individual wires 2 in one by the lot 11 formed in the longitudinal direction of the wire package over a certain length extending matrix 3 embedded, especially included. The feed of the lot 11 to the wire package 6 can in particular be intermittent, so that the wire package 6 in the wire longitudinal direction sequentially successive Drahtgelege 1 be formed. Preferably, in the longitudinal direction of the wire package 6 successive matrices 3 spaced such that a taking place in subsequent steps or required separation of Drahtgelege 1 can be done in a simple manner.

To the soldering device 7 joins an active or passive cooling line, in which the Drahtgelege 1 be cooled. After passing through a pulley with which the / the wires can be pulled through the system, the band can be wired 1 to be wound up on a roll or spool.

The tape with wire 1 can be used for further processing, in particular for the production of piezoelectric elements, in particular piezoelectric actuators. For this purpose, the band, in particular of coil, a (not shown) soldering station can be supplied, in which the main body 5 and the wire scrim 1 aligned, positioned and interconnected. For this purpose, the metallic material of the matrix 3 after appropriate positioning of the wire mesh 1 on or on the base body 5 be melted, so that this with the surface of the main body 5 combines. In this way, an electrically conductive cohesive connection between matrix 3 and basic body 5 are produced, over which the individual wires 2 with the main body 5 are electrically connected.

In particular, from the description of the figures it is clear that the wire cladding, piezo element and manufacturing method proposed herein solve the problem underlying the invention. Advantages and advantageous effects of the wire mesh are in particular in a compact design, scalability, flexibility, mechanical stability and / or reliability. In addition, the proposed Drahtgelege allows a simple and cost-optimized production of piezoelectric elements, in particular piezoelectric actuators.

LIST OF REFERENCE NUMBERS

1

wire structure

2

single wire

3

matrix

4

piezo element

5

body

6

wire package

7

soldering

8th

idler pulley

9

alignment

10

leadership

11

solder

L

length

D

thickness

S

layer thickness

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19945933 C1 [0002]
• DE 102004005943 A1 [0002]
• DE 10200501762 A1 [0002]
• DE 102004004737 A1 [0003]

Claims (18)

Wire scrim ( 1 ) designed for surface contacting a piezoactive material ( 5 ) comprising a plurality of laterally spaced apart ones and by a matrix ( 3 ) of a metallic material electrically conductively interconnected, in particular parallel to each other aligned, individual wires ( 2 ). Drahtgelege according to claim 1, wherein the individual wires in a linear, curved, in particular meandering, arrangement and / or in a uniplanar or multiplanar arrangement, in particular at least in pairs in parallel, are arranged. Wire scrim ( 1 ) according to one of claims 1 or 2, wherein the melting temperature of the metallic material is lower than the melting temperature of the individual wires ( 2 ) that the metallic material separated from the individual wires ( 2 ) is melted. Wire scrim ( 1 ) according to one of claims 1 to 3, wherein at least one of the individual wires ( 2 ) has a tensile strength of at least 1000 N / mm ² , the tensile strength preferably being in the range of 1300 N / mm ² to 1700 N / mm ² . Wire scrim ( 1 ) according to one of claims 1 to 4, wherein at least one of the individual wires ( 2 ) comprises a, in particular with copper, jacketed stainless steel core. Wire scrim ( 1 ) according to claim 5, wherein at least one of the individual wires made of copper, in particular pure copper is produced. Wire scrim ( 1 ) according to one of claims 1 to 6, wherein at least one of the individual wires ( 2 ) has an electrical conductivity of at least 30% to 35% IACS. Wire scrim ( 1 ) according to one of claims 1 to 7, wherein the diameter of the single wire ( 2 ) in the range between 30 microns and 1 mm, preferably between 30 microns and 80 microns, more preferably about 60 microns. Wire scrim ( 1 ) according to any one of claims 1 to 8, wherein the matrix ( 3 ) has a layer thickness (S) in the range between 1 .mu.m to 50 .mu.m, preferably 5 .mu.m to 25 .mu.m, more preferably 20 .mu.m. Wire scrim ( 1 ) according to one of claims 1 to 9, wherein the matrix ( 3 ) consists essentially of tin or a tin alloy, or comprises tin, lead or indium or alloys thereof as an essential component. Wire scrim ( 1 ) according to one of claims 1 to 10, wherein the individual wires ( 2 ) have a mutual distance of up to 1.5 times the wire diameter of the individual wires. Use of a wire mesh ( 1 ) according to one of claims 1 to 11 for producing an electrical surface contacting of a piezoactive material ( 5 ), wherein the wire scrim ( 1 ) by a, in particular by heat application of the metallic material of the matrix ( 3 ), conductive cohesive connection with the piezoactive material ( 5 ) connected is. Manufacturing method for a wire cladding ( 1 ) according to one of claims 1 to 11, comprising the following steps: - providing a plurality of individual wires (3) spaced apart, in particular parallel to one another, and spaced apart from each other ( 2 ) according to a predetermined pattern; Heating at least the individual wires ( 2 ) in a given area; and - supplying a solderable metallic material, in particular solder material, to the heated individual wires ( 2 ) such that this the individual wires ( 2 ) in the manner of a matrix ( 3 ) electrically conductively connects to each other. Manufacturing method according to claim 13, wherein the metallic material is applied in such a way that its layer thickness (S) in the matrix ( 3 ) in the range between 1 μm to 50 μm, preferably 5 μm to 25 μm, more preferably about 20 μm. Manufacturing method according to one of claims 13 or 14, wherein the individual wires ( 2 ) are subjected to an acid treatment before heating and before application of the solder material. Manufacturing method for a piezo element ( 4 ), in particular a piezoelectric actuator, wherein a wire cladding ( 1 ) according to any one of claims 1 to 11 or initially a Drahtgelege ( 1 ) is prepared and provided according to a manufacturing method of claims 13 to 15, wherein the provided wire scrim ( 1 ) with a base body made of a piezoactive material ( 5 ) of the piezo element ( 4 ) is connected to a soldering station in a soldering operation. A manufacturing method according to claim 16, wherein the soldering station is fed with a scrim tape comprising a plurality of serially interconnected wire scrims ( 1 ), and wherein the soldering process preferably prior to separation of individual Drahtgelege ( 1 ) is carried out. Piezo element ( 4 ), in particular piezoactuator, comprising one of a piezoactive material manufactured basic body ( 5 ) and a trained according to one of claims 1 to 11 wire scrim ( 1 ) with metallic matrix ( 3 ), which with the surface of the body ( 5 ) Is connected by a conductive cohesive connection.

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