DE102011015219A1 - Solderable electrode for electrical piezoelectric actuator, has mesh electrode element and strip-shaped solder layer which is connected and pressed together with mesh electrode element by upper and lower rollers - Google Patents

Abstract

The solderable electrode (1) has a mesh electrode element (2) and a strip-shaped solder layer (3) whose lower side is connected with the upper side of the mesh electrode element. The mesh electrode element and strip-shaped solder layer are pressed together by the upper and lower rollers. The mesh electrode element is provided with wire mesh and metallic wires (7,8). The strip-shaped solder layer is comprised of knitted fabric or braided fabric. An independent claim is included for method for manufacturing solderable electrode.

Description

The present invention relates to a solderable electrode and a method of manufacturing such a solderable electrode.

Such solderable electrodes are versatile. A possible application is given in the contacting of electrical actuators, which are constructed for example of layer materials. In such layer actuators, individual piezoelectric layers are stacked and each layer is contacted individually from the sides. By applying an electrical voltage, the entire length of the electric actuator changes accordingly.

In such actuators, it is important that the plurality of individual piezoelectric layers can be reliably and permanently reliably contacted even though the entire actuator and also the electrode contacting the actuator are moved, thereby periodically changing their length, whereby relative movements between the electrode and the layer actuator may occur.

For these and other applications solderable electrodes have become known, which are provided with a mesh electrode to permanently reliably contact via the network the electrical load or the Schichtaktuator. In this case, in the manufacturing process, the solderable electrode is soldered to the component to be supplied, such as the Schichtaktuator. It has been found in the prior art to be expensive to provide the required amount of solder targeted to ensure proper soldering.

With the DE 10 2006 057 178 A1 a solderable network has become known in which the wires woven over a net surface consist of a core which is radially surrounded over its length by a thick-layer tinning in order to provide over the net surface a homogeneous and an equally distributed quantity of solder for the soldering process.

This prior art works reliably, but the production is relatively complex overall.

It is therefore the object of the present invention to provide a solderable electrode which offers reliable soldering properties and which is simpler or less expensive to manufacture.

This object is achieved by a solderable electrode with the features of claim 1. The inventive method is subject of claim 11. Preferred embodiments and further developments of the invention are specified in the dependent claims. Further advantages, features and embodiments of the invention will become apparent from the embodiment.

The solderable electrode according to the invention has a mesh electrode with at least one strip-shaped solder layer. In this case, the strip-shaped solder layer is connected to the network electrode. For this purpose, the mesh electrode is pressed from at least one side with the strip-shaped solder layer.

The solderable electrode according to the invention has many advantages. A significant advantage is the simple manufacturing process. First, a mesh electrode can be made in a conventional manner that does not have a supply of solder material for soldering. Subsequently, the finished or at least semi-finished mesh electrode is pressed with at least one strip-shaped solder layer. By pressing a - at least temporarily - solid bond between the mesh electrode and the strip-shaped solder layer is produced. The bond produced is sufficient for further processing of the solderable electrode and for mounting on the product to be soldered. Subsequently, the solderable electrode can be soldered to the electrical load such as a Schichtaktuator in a suitable oven or via another type of heat supply to produce reliable contact with the individual piezoelectric layers of the actuator and to ensure permanent.

The strip-shaped solder layer connected to the network electrode constitutes a solder reservoir, which ensures a secure and sufficient contact with the product to be contacted during the subsequent soldering. As a result, the following soldering process can be carried out completely without the supply of additional soldering material.

Another significant advantage of the solderable electrode according to the invention is that a wide variety of materials of the mesh electrode and the strip-shaped solder layer can be used. On the other hand, if a net electrode is to be galvanically galvanized or if the wires used to produce the net electrode are to be galvanically coated with a solder layer beforehand, the problem may arise that certain combinations of materials can not be applied galvanically. As a result, depending on the material of the mesh electrode, only certain brazing materials are possible.

In modern soldering processes, fixing on galvanically compatible materials can severely limit the choice of material for the mesh electrode and the solder layer. This can lead to significant product, quality and / or price disadvantages, which are avoided with the present invention, since a mechanical connection between the mesh electrode and the strip-shaped solder layer is produced, which works reliably regardless of the materials used.

The shape and the structure of the solderable electrode are selectable within extremely wide limits, since in principle any desired external shape can be produced.

In a preferred embodiment, the mesh electrode comprises at least one wire mesh and / or at least one wire mesh and / or at least one Drahtgewirk. The mesh electrode may also comprise a wire fleece or a wire felt or the like.

Preferably, the mesh electrode is elastically formed in at least one dimension and in particular in the longitudinal direction, in order to be able to participate elastically in the contacting of a piezoelectric actuator, for example, the corresponding changes in length.

In all embodiments, the mesh electrode consists at least partially of metallic wires or of wires which have a metallically conductive surface. Particularly preferred is a wire mesh is used, wherein the wire mesh consists in particular of metallic wires. The wire mesh may also consist of synthetic or natural material wires, which are surrounded by a correspondingly structured metallic layer to ensure the necessary conductivity.

Advantageously, the strip-shaped soldering or soldering layer consists entirely or at least predominantly of at least one soldering or soldering material. In particular, the strip-shaped solder layer consists at least substantially completely of at least one solder material. It is also possible that the strip-shaped solder layer consists of two or more different solder materials.

In principle, the use of all solder materials is possible. Both soft solders and brazes are preferred. The use of the respective solder material depends on the selected operating environment of the finished solderable electrode and the other requirements.

In particularly preferred embodiments, the strip-shaped solder layer is formed as a flat solder foil or as a flat solder plate.

But it is also possible that the strip-shaped solder layer comprises at least one Lotgewirk, a Lotgestrick, a braid, a Lotfleece, a Lotfilz or a Lotgewebe or the like.

Whether the strip-shaped solder layer consists of a solid plate or film, or whether the strip-shaped solder layer consists of a woven fabric or the like, is basically insignificant, provided that the strip-shaped solder layer is structured such that a distribution of the solder layer is made possible and ensured during the subsequent soldering process.

Preferably, the strip-shaped solder layer is at least partially and / or at least partially connected to the mesh electrode by brushing. The solder layer is placed on the wire mesh and processed with a brush and / or with a tool with bristles and brushed at least selectively in the wire mesh. As a result, the thin solder layer adapts to the wire mesh and is connected to it, so that it reliably adheres to it during the following process steps. The use of an adhesive material is not required. Optionally, however, an adhesive material can be used.

It is also possible and preferred to connect the strip-shaped solder layer at least partially with the mesh electrode by a needle operation. For this purpose, the solder layer is placed on the wire mesh. Both layers are then pressed together by pressing needles or needle-like tools on the solder layer, which locally deform the solder layer and press into the interstices of the wire mesh. It is also possible that the needles pierce the solder layer and press parts of the solder layer into the wire mesh. The needle tip is adjusted according to the wire knit and the solder layer. This can, for. B. pointed, dull, round, flat, pyramidal, or have any other shape.

In preferred developments, the solder layer has a thickness between 10 μm and 150 μm and in particular between 20 μm and 50 μm. Even larger or smaller thicknesses are possible. The choice of the thickness of the solder layer depends essentially on the required Lotmenge in the soldering process. In particular, the quantity of solder is also influenced by the thickness of the mesh electrode or by its wire diameter and the size of the solderable electrode.

Particularly preferably, the solderable electrode has a wire mesh as a mesh electrode. The wire diameter of the warp and / or weft wires of the mesh electrode is preferably between 30 .mu.m and 150 .mu.m and in particular between 40 .mu.m and 100 .mu.m. Depending on the application, smaller or larger values are also possible here. So are net electrodes with wire diameters of 300 μm or 500 μm or of 1 mm or more is possible and preferred.

In all embodiments, it is particularly preferred that the warp wires and the weft wires of the wire cloth extend at an angle to the longitudinal direction of the solderable electrode. The angle between the longitudinal direction and the warp wires and / or the weft wires is preferably between 30 ° and 60 °. But also possible angles between 15 ° and 75 °. In concrete embodiments, the angle is 45 °. Obliquely oriented to the longitudinal direction warp and weft wires of the wire fabric ensure a high elasticity of the mesh electrode in the longitudinal direction of the solderable electrode. As a result, a high elasticity of the solderable electrode can be ensured when used on piezoelectric actuators, which contributes to a high level of operational safety.

Preferably, the mesh electrode and at least one strip-shaped solder layer are calendered together. By calendering the necessary pressing pressure is applied to the network electrode so firmly connect at least for further processing with the solder layer, that in the subsequent further processing and the soldering of the solderable electrode, the probability of failure is very low or practically zero.

During calendering, the mesh electrode and the strip-shaped layer of solder laid thereon or below run through two rotating rolls which have a defined spacing. In this case, the distance of the rotating rollers is dimensioned such that it is less than the thickness of the wire mesh and the solder layer arranged thereon. As a result, a high pressure is exerted on the mesh electrode and the strip-shaped solder layer, which leads to a local deformation of the strip-shaped solder layer and / or the mesh electrode. It has been found that this creates a sufficiently strong connection between the strip-shaped solder layer and the mesh electrode.

In all embodiments, it is possible and preferred that the network electrode is folded over with the associated solder layer over at least a portion. In this case, the solder layer can be arranged inside or outside.

It is possible and preferred that at least one electrical connection element is fastened in the folded-over region. In particular, the refolding is carried out over the length of at least one connecting section. It is also possible that the net electrode is folded in total. In this case, one or more connection electrodes can be located in the folding area.

It is possible that the net electrode with the strip-shaped solder layer arranged thereon is folded in such a way that the solder layer is completely or at least partly surrounded by the net electrode via the folded-in section.

It is also possible that the solder layer is located on the outside of the folded net electrode. It is also preferable that a solder layer is provided on one side of the mesh electrode and a solder layer on the other side of the mesh electrode, so that the mesh electrode is connected to a solder layer on both sides. This allows a greater distribution of Lotmenge. Accordingly, a thinner stripe-shaped solder layer can be used on both sides.

In the method according to the invention for producing a solderable electrode, a mesh electrode with at least one strip-shaped solder layer is at least partially covered, and then the mesh electrode is pressed with the strip-shaped solder layer.

The method according to the invention also has many advantages, since it provides a simple method for producing a solderable electrode, with which a reliable soldering with electrical consumers is possible. In this case, the solder reservoir needed for soldering is provided at the solderable electrode.

The pressing process can be carried out in a continuous, continuous process. But it is also possible that the pressing process is carried out in a batch process. For example, the pressing can also be carried out in a punching operation.

It is particularly preferred that the or at least one pressing takes place during calendering.

Preferably, the net electrode is folded at least once over at least a portion to ensure the reception and the contacting of an electrical connection element.

Further advantages and features of the present invention will become apparent from the embodiments, which are explained below with reference to the accompanying figures.

In the figures show:

1 a schematic plan view of a solderable electrode according to the invention;

2 a solderable electrode with an electrical connection in a schematic view;

3 an enlarged schematic cross section through the terminal end of a solderable electrode;

4 a schematic longitudinal section through one end of the solderable electrode;

5 a schematic representation of the calendering process;

6 a schematic cross-sectional view of a solderable network on an enlarged scale; and

7 a schematic cross section through a further embodiment of a solderable electrode according to the invention.

With reference to the accompanying figures, an embodiment of a solderable electrode will be described below 1 explained in more detail.

In the 1 illustrated electrode comprises a solder layer 3 , here as a plate-shaped foil 9 is executed. The solder plate 11 is here below the grid electrode 2 arranged. Of course, it is also possible that the solder layer 3 above the mesh electrode 2 is provided. The here shown rectangular solder foil 9 and the corresponding rectangular section of the mesh electrode 2 may also have other shapes.

The mesh electrode 2 consists of a wire mesh 6 made of wires 7 and 8th or warp wires 12 and weft wires 13 consists. The wire diameter 18 the weft wires 13 and the wire diameter 17 the warp wires 12 are here in the embodiment between about 40 microns and 150 microns. The exact dimensions depend on the intended application.

In 2 is a schematic plan view of a finished solderable electrode shown. The solderable electrode 1 includes a wire mesh 6 as mesh electrode 2 , The wire mesh 6 or the warp wires 12 and the weft wires 13 of wire mesh 6 point here to the longitudinal direction 15 the solderable electrode 1 an angle 14 on, in the embodiment 45 Degree is.

At the connection section arranged on the left in the exemplary embodiment 16 is a connection element 19 added. For secure reception of the connection element 16 can the connection section 16 folded over or folded onto each other to secure the connection element 19 to ensure. It is also possible that the mesh electrode 2 the solderable electrode 1 in total with the solder layer 3 is folded.

3 shows a cross section through the solderable electrode 1 , It is the solder foil 9 executed solder layer 3 by pressing with the mesh electrode 2 connected. After the pressing process, the lateral sections of the mesh electrode 2 folded down, with a connecting element inside 19 may be provided to the solderable electrode 1 to connect to a power or voltage source or a control device or the like.

In the schematic representation according to 3 are on the left side the bending edges 20 and 21 drawn, while on the right side both bending edges in total with the reference numeral 36 are provided. At this point it should be noted that the representation of the 3 is a schematic representation. It is possible that only one bending edge is provided on the right and the left side. In areas where no electrical connection element 19 is provided, for example, is the upper right section 33 with the associated upper right section 23 the mesh electrode regularly directly on the lower portion of the solder layer 34 on, so only one bending edge 36 is available. The upper left section 22 the mesh electrode 2 then lies with the upper left section 32 the solder layer 3 directly on the lower section 24 the mesh electrode 2 on.

The shown in the figures here column between the individual components are only the clarification of the principle and are not present in a real design in the rule to ensure a correspondingly tight fit of the individual components together.

4 shows a longitudinal cross-section in the region of the connection section 16 in which the electrical connection element 19 not between the individual layers of the solderable electrode 1 but outside z. B. dotted is provided. Inside lies between the layers of the folded net electrode 2 one layer of the solder foil in each case 9 , The connection element 19 could also be included in the interior between the individual layers.

While the thickness 10 the solder foil 9 typically in the range of 20 to 70 microns, the thickness is 27 a position of the mesh electrode 2 here between 50 μm and 150 μm. The total thickness 31 The finished solderable electrode adds accordingly. In the areas where an electrical connection element 19 is provided, the thickness increases 31 strong enough while it is correspondingly lower in the other sections.

5 shows the calendering device 28 , with the here the solder layer 3 with the mesh electrode 2 is pressed. The mesh electrode 2 with the solder layer applied to it 3 has an initial thickness before calendering 35 greater than the distance between the two rollers 29 and 30 of the calendering device 28 , When passing through the calendering device 28 becomes the composite of mesh electrode 2 and solder layer 3 generated and amplified. In this case, both the thickness of the solder layer 3 as well as the thickness of the mesh electrode 2 be reduced until the total thickness 31 established. Due to the massive pressure on the mesh electrode and the solder layer, a strong bond of the mesh electrode with the solder layer is formed. This can additionally by folding over the mesh electrode 2 be strengthened.

Calendering generally reduces the total thickness between 10% and 60% depending on the set parameters. Preference is given to pressings greater than 20%. In a concrete embodiment, a good result was achieved with a reduction of the thickness between 30% and 40%.

In 6 Figure 3 is a schematic enlarged cross section of the final solderable electrode 1 shown. Pictured are some warp wires 12 and a weft wire 13 , By calendering the layer of mesh electrode 2 and solder layer 3 have stuck to the crests of the weft wires 13 (and at the not visible here domes of the warp wires 12 ) Flattening 25 the mesh electrode and at the corresponding points of the solder layer 3 have corresponding flattenings 26 the solder layer 3 result.

In the example shown, the solder layer 3 on the website 4 of wire mesh 6 provided while on the page 5 no solder layer is present. But it is also possible, in each case a solder layer on both sides of the mesh electrode 3 provided. The fat 10 each applied solder layers may be correspondingly lower to still ensure a reliable soldering. As a rule, the thickness of the solder layers and thus the amount of solder material are adapted to the soldering process.

7 shows an embodiment in which the mesh electrode 2 on a correspondingly large layer of solder 9 was hung up and both together along the bending edges 20 and 36 were folded over. The solder layer 9 is outside here while the mesh electrode 2 completely from the solder layer 9 is surrounded. After the bending or folding process, the mesh electrode 2 together with the solder layer 9 calendered. In doing so, a surface is created, as they are approximately in 6 is shown. Overall, a firm connection is created, which holds both components safely until the soldering process.

Overall, the invention of the invention provides a simple method and a solderable electrode which can be produced easily, with which, for example, electrical actuators can be reliably and permanently actuated.

LIST OF REFERENCE NUMBERS

1

solderable electrode

2

mesh electrode

3

solder layer

4

page

5

page

6

wire cloth

7

wire

8th

wire

9

solder foil

10

thickness

11

solder plate

12

warp wire

13

weft wire

14

angle

15

longitudinal direction

16

connecting section

17

Wire diameter

18

Wire diameter

19

connecting element

20

bending edge

21

bending edge

22

upper left portion of the mesh electrode

23

Upper right section of the mesh electrode

24

lower section of the mesh electrode

25

Flattening of the mesh electrode

26

Flattening of the solder layer

27

Thickness of the mesh electrode

28

Kalandriergerät

29

roller

30

roller

31

Total thickness, final thickness

32

upper left portion of the solder layer

33

Upper right section of the solder layer

34

lower portion of the solder layer

35

Thickness before calendering

36

bending edge

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 102006057178 A1 [0005]

Claims (12)

Solderable electrode ( 1 ) with a mesh electrode ( 2 ) and at least one strip-shaped solder layer ( 3 ), wherein the strip-shaped solder layer ( 3 ) at least temporarily with the network electrode ( 2 ), to which the network electrode ( 2 ) of at least one side ( 4 . 5 ) with the strip-shaped solder layer ( 3 ) is compressed. Solderable electrode ( 1 ) according to claim 1, wherein the mesh electrode ( 2 ) at least one wire mesh ( 6 ) and / or at least one wire mesh and / or at least one Drahtgewirk comprises and in particular at least partially made of metallic wires ( 7 . 8th ) and / or wherein the strip-shaped solder layer ( 3 ) comprises at least one Lotgewirk, a Lotgestrick, a braid, a Lotfilz or a Lotgewebe. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the strip-shaped solder layer ( 3 ) consists at least predominantly of at least one solder material, and / or wherein the strip-shaped solder layer ( 3 ) as a flat solder foil ( 9 ) and in particular as a flat solder plate ( 11 ) is trained. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the strip-shaped solder layer ( 3 ) at least partially with the mesh electrode ( 2 ) is connected by brushing. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the strip-shaped solder layer ( 3 ) at least partially with the mesh electrode ( 2 ) is connected by a needle operation. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the solder layer ( 3 ) a thickness ( 10 ) between 10 μm and 150 μm and in particular between 20 μm and 50 μm. Solderable electrode ( 1 ) according to one of the preceding claims, wherein at least one wire diameter ( 17 . 18 ) of the warp and / or weft wires ( 12 . 13 ) of the grid electrode ( 2 ) is between 30 μm and 150 μm and in particular between 40 μm and 100 μm. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the warp wires ( 12 ) and the weft wires ( 13 ) of wire mesh ( 6 ) at an angle ( 14 ) to the longitudinal direction ( 15 ), where the angle ( 14 ) is in particular between 30 ° and 60 °. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the network electrode ( 2 ) and at least one strip-shaped solder layer ( 3 ) are calendered together. Solderable electrode ( 1 ) according to one of the preceding claims, wherein the network electrode ( 2 ) with the associated solder layer ( 3 ) over at least one section ( 15 ) is folded over and / or wherein the network electrode ( 2 ) with the associated solder layer ( 3 ) via at least one connection section ( 16 ) is folded over, wherein an electrical connection element ( 19 ) is folded in with. Method for producing a solderable electrode ( 1 ), wherein a network electrode ( 2 ) with at least one strip-shaped solder layer ( 3 ) and then the mesh electrode ( 2 ) with the strip-shaped solder layer ( 3 ) is pressed. Method according to the preceding claim, wherein the network electrode ( 2 ) on both sides ( 4 . 5 ) with at least one strip-shaped solder layer ( 3 ) and then pressed and / or wherein the mesh electrode ( 2 ) is folded at least once over at least one section.

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