Electrical device with terminal region and method for producing a terminal region

Abstract

An electrical device having a terminal region for connection with a printed circuit board. The terminal region has a stranded wire and an enclosure piece surrounding the stranded wire. The enclosure piece is connected with the stranded wire, for example, by thermal diffusion bonding.

Claims

1. An assembly of an electrical device and a printed circuit board, the electrical device comprising a terminal region for connection with the printed circuit board, the printed circuit board comprising contacts for electrical connection, wherein the terminal region consists of a single stranded wire and an enclosure piece, the enclosure piece surrounding the single stranded wire, wherein the single stranded wire includes a plurality of individual wires, and the individual wires have individual insulations, wherein the single stranded wire has an outer insulation enclosing all the individual wires, and wherein the individual insulations are present in regions outside the terminal region and are at least partially removed in the terminal region, wherein the outer insulation is present in regions outside the terminal region and is at least partially removed in the terminal region, in which the enclosure piece consists of a metallic band piece, in which the enclosure piece has marginal zones that overlap, wherein the single stranded wire is connected with the enclosure piece by thermal diffusion bonding, wherein the overlapping marginal zones are connected to each other only through thermal diffusion bonding, wherein the electrical device is mounted on the printed circuit board, wherein the terminal region is directly connected with the contacts of the printed circuit board by soldering, and wherein the single stranded wire terminates flush with the enclosure piece or protrudes out of the enclosure piece at both ends; wherein the electrical device includes a second terminal region, the second terminal region comprising a second end of the single stranded wire and a second enclosure piece, the second enclosure piece surrounding the second end of the single stranded wire, the single stranded wire forms a winding for the device in which a first end of the single stranded wire is at the terminal region and the second end of the single stranded wire is at the second terminal region, the winding being formed by a portion of the single stranded wire between the first end and the second end; wherein after the single stranded wire is connected to the enclosure piece and the winding is formed around a winding support, the electrical device is mounted on the printed circuit board; wherein the winding support includes two integral holder elements for holding the single stranded wire adjacent to or at the terminal region and the second terminal region; wherein each of the two integral holder elements clamps around a portion of a circumference of the single stranded wire.

2. The assembly of claim 1, in which the single stranded wire extends through the entire terminal region.

3. The assembly of claim 1, in which the electrical device is mounted on the printed circuit board by pin through hole mounting.

4. The assembly of claim 3, wherein the terminal region is inserted into the printed circuit board and solder is directly applied on the terminal region.

5. The assembly of claim 1, in which the electrical device is mounted on the printed circuit board by surface mounting.

6. The assembly of claim 5, wherein the terminal region includes a kink or bend and comprises a flat bottom side positioned on and connected to the printed circuit board.

7. The assembly of claim 1, in which the terminal region is rectangular in shape, having flat side surfaces.

8. The assembly of claim 1, in which the terminal region is oriented downwards.

9. The assembly of claim 1, wherein the insulations of the individual wires are lacquer layers.

10. The assembly of claim 1, wherein the individual insulations and the outer insulation are present in the winding and located outside the terminal region and outside the second terminal region.

11. The assembly of claim 1, wherein the winding support is an insulated material.

12. The assembly of claim 1, wherein the terminal region and the second terminal region are arranged at a distance that is close to the winding, the distance being less than 10 mm.

13. An assembly of an electrical device and a printed circuit board, the electrical device comprising a terminal region for connection with the printed circuit board, the printed circuit board comprising contacts for electrical connection, wherein the terminal region consists of a single stranded wire and an enclosure piece, the enclosure piece surrounding the single stranded wire, wherein the single stranded wire includes a plurality of individual wires, and the individual wires have individual insulations, wherein the single stranded wire has an outer insulation enclosing all the individual wires, and wherein the individual insulations are present in regions outside the terminal region and are at least partially removed in the terminal region, wherein the outer insulation is present in regions outside the terminal region and is at least partially removed in the terminal region, in which the enclosure piece consists of a metallic band piece, in which the enclosure piece has marginal zones that overlap, wherein the single stranded wire is connected with the enclosure piece by thermal diffusion bonding, wherein the overlapping marginal zones are connected to each other only through thermal diffusion bonding, wherein the electrical device is mounted on the printed circuit board, wherein the terminal region is directly connected with the contacts of the printed circuit board by soldering, and wherein the single stranded wire terminates flush with the enclosure piece or protrudes out of the enclosure piece at both ends; wherein the electrical device includes a second terminal region, the second terminal region comprising a second end of the single stranded wire and a second enclosure piece, the second enclosure piece surrounding the second end of the single stranded wire, the single stranded wire forms a winding for the device in which a first end of the single stranded wire is at the terminal region and the second end of the single stranded wire is at the second terminal region, the winding being formed by a portion of the single stranded wire between the first end and the second end; wherein the terminal region and the second terminal region are arranged at a distance that is close to the winding, the distance being less than 10 mm.

Description

(1) The subjects described here are explained in greater detail below with reference to schematic exemplary embodiments.

(2) In the figures:

(3) FIG. 1A is a perspective view of one embodiment of a device,

(4) FIG. 1B is a sectional view of the terminal region of the device of FIG. 1A,

(5) FIG. 2A is a perspective view of a further embodiment of a device,

(6) FIG. 2B is a sectional view of the terminal region of the device of FIG. 2A,

(7) FIG. 3 is a perspective view of a further embodiment of a device,

(8) FIGS. 4A to 4G show method steps for production of a terminal region of a device.

(9) FIG. 5 illustrates a schematic view of a terminal region inserted in a printed circuit board with solder applied to the terminal regions.

(10) FIG. 6 illustrates a schematic view of a terminal region with a bend.

(11) In the following figures identical reference signs preferably relate to functionally or structurally corresponding parts of the various embodiments.

(12) FIG. 1A shows a device 1 having a terminal region 2 for connecting the device 1 to a printed circuit board. The device 1 for example is an inductive device.

(13) The terminal region 2 is configured in particular in the form of a terminal pin. The terminal region 2 is insertable for example into holes of a printed circuit board. In particular, the terminal region 2 is suitable for pin through hole mounting. The terminal region 2 points downwards.

(14) In the present case, the terminal region 2 has a rectangular cross-sectional shape. Depending on the desired terminal design, the terminal region 2 may also have another shape. The component 1 may have a plurality of terminal regions 2. In the present case, two terminal regions 2 are provided, which are arranged adjacent one another.

(15) The terminal region 2 has a stranded wire 3 and an enclosure piece 4 arranged therearound. The stranded wire 3 extends into the enclosure piece 4. In particular, the ends of the stranded wire 3 and of the enclosure piece 4 terminate flush with one another. Thus, in the case of PTH mounting the stranded wire 3 extends directly into the printed circuit board. In this way, local heat peaks at the printed circuit board can be avoided. In addition, an improvement in electrical behavior can be achieved thereby, for example in the case of resistance.

(16) The stranded wire 3 may for example be configured as a high-frequency stranded wire. The stranded wire 3 has a multiplicity of individual wires, for example 100 to 5000 individual wires. The stranded wire 3 has a round cross-sectional shape for example outside the terminal region 2.

(17) The stranded wire 3 is surrounded by external insulation 8 outside the terminal region 2. The insulation 8 is configured in particular as an insulating sleeve, in which all the individual wires are accommodated. Each individual wire may additionally be surrounded outside the terminal region 2 by internal insulation, which takes the form, for example, of an enamel layer. The individual wires comprise copper, for example. The individual wires for example have thicknesses of between 0.02 and 0.5 mm.

(18) The stranded wire 3 forms a winding 5, in particular a coil, of the device 1. The winding 5 is arranged on a support 6. The support 6 comprises an insulating material.

(19) The enclosure piece 4 in particular is a so-called splice crimp. A splice crimp is a metallic band piece which is provided in a flat shape, for example, and then bent around a conductor. In this way, the enclosure piece 4 obtains its geometry, in particular its tubular or sleeve shape, only during arrangement around the stranded wire 3. The enclosure piece 4 for example comprises a metal. For example, the enclosure piece 4 comprises copper, brass, bronze or other copper alloys. The enclosure piece 4 may additionally be tinned. The enclosure piece 4 is made, for example, from a flat, metallic band.

(20) The terminal regions 2 are mechanically fixed by means of a holder 7. For example, the terminal regions 2 are clamped in place in the holder 7. The holder 7 is arranged on the support 6. The holder 7 may be an integral part of the support 6.

(21) The terminal regions 2 may be arranged very close to the winding 5, for example at a distance of a few mm, in particular at a distance of up to 10 mm.

(22) The enclosure piece 4 is directly connected with the stranded wire 3. The connection is produced in particular by thermal diffusion bonding. To this end, the parts to be connected together, i.e. the enclosure piece 4 and the stranded wire 3, are pressed together and simultaneously heated. The temperature is here below the melting temperature of the parts to be connected. The outer contour of the terminal region 2, for example a rectangular shape, is produced in the process.

(23) FIG. 1B is a sectional view of the terminal region 2 of the device 1 of FIG. 1A. The associated device 1 may also be differently configured from that in FIG. 1A.

(24) The terminal region 2 has a rectangular outer contour. The individual wires 9 of the stranded wire 3 are identifiable. The enclosure piece 4 completely surrounds the stranded wire 3. The enclosure piece 4 has marginal zones 10, 11 which overlap. The enclosure piece 4 tightly encloses the stranded wire 3. The individual wires 9 lie closely against one another. It is apparent from the shape of the enclosure piece 4, in particular from the overlap of the marginal zones 10, 11 and the tight enclosure of the stranded wire 3 by the enclosure piece 4, that the enclosure piece 4 is not preshaped as a sleeve but acquires its sleeve shape only when it is wrapped around the stranded wire 3.

(25) The enclosure piece 4 is firmly connected mechanically and electrically with the individual wires 9 of the stranded wire 3 by thermal diffusion bonding. The individual wires 9 are likewise firmly connected together mechanically and electrically by thermal diffusion bonding. Some residues of insulation of the individual wires 9 and/or of external insulation of the stranded wire 3 are apparent.

(26) These residues make it apparent that the insulation is removed only during thermal diffusion bonding. Immediately prior to diffusion bonding the individual wires 9 are still surrounded by insulation 14. The insulation 14 melts during diffusion bonding, such that an electrical connection of the individual wires 9 may be produced. The stranded wire 3 may also still have the external insulation 8 immediately prior to the diffusion bonding. This insulation 8 also melts during diffusion bonding, so enabling electrical connection of the stranded wire 3 with the enclosure piece 4.

(27) FIG. 2A shows a further embodiment of a device 1 comprising a terminal region 2. Unlike the device 1 of FIG. 1A, the terminal region 2 has an approximately round cross-sectional shape.

(28) FIG. 2B is a sectional view of the terminal region 2 of the device 1 of FIG. 2A. Here too, the overlap of the marginal zones 10, 11 is apparent.

(29) The process of shaping the enclosure piece 4 and the entire terminal region 2 by exerting external pressure is apparent from the incompletely round external geometry. It is apparent in particular from edges 23, 24 visible at the bottom that the shape of the terminal region 2 is formed by compaction between a lower die and one or more upper dies. The edges 23, 24 reveal the boundaries between lower and upper dies.

(30) FIG. 3 is a perspective view of a further embodiment of a device 1. Unlike the devices 1 of FIGS. 1A and 2A, here the terminal regions 2 are not fixed by a holder 7. The position of the terminal regions 2 is defined merely by the positioning of the stranded wire 3 on a support 6. In particular, the stranded wire 3 rests laterally against the support 6. The lack of direct fixation of the terminal region 2 increases mounting flexibility of the device 1.

(31) The device 1 has four terminal regions 2, which project downwards from the support 6. The terminal regions 2 may be inserted into a printed circuit board 30 for PTH mounting, as shown in FIG. 5. Attachment by soldering, for example wave soldering, may be performed. The solder material 31 is applied directly to the terminal regions 2 as shown in FIG. 5.

(32) Alternatively, the device 1 may also be mounted using surface mounting. To this end, the device 1 is arranged on a printed circuit board and the terminal regions 2 are attached by soldering to the printed circuit board. For this purpose, the terminal regions 2 may also be bent outwards or inwards. Bending may for example be produced prior to or during thermal diffusion bonding by a suitable forming tool.

(33) Alternatively, electrical connection is also possible using a screw or clamp connection of the terminal region 2.

(34) The terminal regions 2 may also serve as supporting legs on arrangement of the device 1 on a printed circuit board or another support.

(35) FIGS. 4A to 4G show method steps for production of a terminal region 2. The method is suitable for example for producing the terminal regions 2 shown in FIGS. 1A to 3.

(36) FIG. 4A shows a first method step, in which a band piece 13 is provided and bent around a stranded wire 3, such that an enclosure piece 4 is formed from the band piece 13. The stranded wire 3 is surrounded by external insulation 8 and has a multiplicity of individual wires 9 which are each surrounded by insulation 14.

(37) The band piece 13 is for example cut from a metallic band. The band piece 13 is uniform in shape and thus does not have differently shaped regions. A particularly space-saving terminal region 2 may be formed using such a band piece 13. As material, the band piece 13 for example comprises copper, brass, bronze or an alloy of such materials. The band piece 13 is formed from a uniform material and does not have any regions of different materials.

(38) The band piece 13 is bent around the stranded wire 3. To this end, for example, the arrangement is inserted into a crimping device and the band piece 13 is introduced and bent around the stranded wire 3 through the exertion of force (see arrows). In the process, marginal zones 10, 11 of the band piece 13 are laid on top of one another.

(39) Such a band piece 13 or the enclosure piece 4 formed therefrom is conventionally known as a splice crimp. The enclosure piece 4 differs from a prefabricated sleeve, into which one or more conductors are inserted. The present enclosure piece 4 acquires its sleeve shape only during arrangement thereof around the stranded wire 3. The stranded wire 3 is thus not inserted into the enclosure piece 4.

(40) FIG. 4B is a sectional view of the arrangement 25 of enclosure piece 4 and stranded wire 3 after formation of the enclosure piece 4 around the stranded wire 3. The insulation 8, 14 is still present, meaning that there is no electrical connection between enclosure piece 4 and stranded wire 3.

(41) FIG. 4C is a side view of the arrangement 25 according to FIG. 4B. The arrangement 25 of enclosure piece 4 and stranded wire 3 has a somewhat greater thickness d than adjacent regions of the stranded wire 3, since no compaction has as yet taken place. A free end 15 of the stranded wire 3 projects out of the enclosure piece 4.

(42) FIG. 4D shows the method step of thermal diffusion bonding and simultaneous compacting of the terminal region 2.

(43) Force (see arrows) is exerted from at least one side onto the arrangement 25 of stranded wire 3 and enclosure piece 4. To this end, for example, a compaction tool with a plurality of stamps 16, 17, 18, 19 is used. For example, the arrangement of stranded wire 3 and enclosure piece 4 rests on the lower stamp 19. The arrangement 25 may for example also be held between two stamps 17, 19.

(44) The contact surfaces 26, 27, 28, 29 of the stamps 16, 17, 18, 19 against the enclosure piece 4 determine the outer contour of the terminal region 2. The stamps 16, 17, 18, 19 may each have flat contact surfaces 26, 27, 28, 29, such that the terminal region 2 has flat side faces. The stamps 16, 17, 18, 19 may also have rounded contact surfaces 26, 27, 28, 29, such that the terminal region 2 has correspondingly rounded outer contours. The stamps 16, 17, 18, 19 may also have a combination of flat and rounded contact surfaces 26, 27, 28, 29. The stamps 16, 17, 18, 19 may for example exert pressure simultaneously or one after the other.

(45) During compression the arrangement 25 of stranded wire 3 and enclosure piece 4 is heated. In the process, electrodes 20, 21 are for example applied against opposing sides of the enclosure piece 4. The electrodes 20, 21 may be integrated into the compaction tool. Due to the ohmic resistance of the insulation 8, 14, the stranded wire 3 heats up (resistance welding), such that the insulation 8, 14 melts, as indicated here by dashed boundaries. In the process, the insulation 8, 14 evaporates at least in part. The insulation 8, 14 is largely removed from the individual wires 9. All that may remain is locally molten residues of the insulation 8, 14.

(46) The continuous application of pressure results in closure of any cavities which arise inter alia through melting of the insulation 8, 14, and the terminal region 2 adopts a compact shape. Compaction is enabled inter alia by a growing overlap between the marginal zones 10, 11. Under the applied pressure and the elevated temperature the exposed individual wires 9 are permanently electrically and mechanically connected together and with the enclosure piece 4 by thermal diffusion bonding. The method may also be denoted as hot crimping or diffusion welding.

(47) FIG. 4E shows the terminal region 2 after the connection and compaction process. The terminal region 2 now has a rectangular outer contour. The terminal region 2 is suitable for example for PTH mounting. Insulation residues 12 are apparent in the form of clumped particles. The individual wires 9 are connected firmly together and with the enclosure piece 4. Depending on the selected process parameters and geometries, after the connection and compaction process the individual wires 9 may no longer be identifiable as such with the naked eye. The terminal region 2 may thereby have the appearance of a uniform element.

(48) The terminal region 2 is filled within the enclosure piece 4 completely or almost completely with the material of the individual wires 9.

(49) FIG. 4F is a side view of the terminal region 2 from FIG. 4E. Due to the compaction, the terminal region 2 has a smaller thickness d than the region of the stranded wire 3 which is still provided with external insulation 8 outside the terminal region 2. A region 22 may be present adjacent the terminal region 2 and the enclosure piece 4 in which the stranded wire 3 does not have any external insulation 14. This region may however be kept small by the readily controllable heating process. This also enables the formation of a terminal region 2 in the immediate vicinity of a winding of the device.

(50) In a further method step the projecting region of the free end 15 of the stranded wire 3 may be detached, such that the enclosure piece 4 terminates flush with the stranded wire 3. An end region of the enclosure piece 4 may also be detached at the same time.

(51) FIG. 4G shows the terminal region 2 after detachment of the projecting region of the stranded wire 3. The terminal region 2 may now be fixed in a holder or be used without further fixation for connection to a printed circuit board.

(52) The described method enables good electrical conductivity to be achieved with a high mechanical connection strength. In addition, the method enables simple, readily controllable production of an electrical terminal for the device 1, such that the connection can be produced at low cost and within a short time.

LIST OF REFERENCE SIGNS

(53) 1 Device 2 Terminal region 3 Stranded wire 4 Enclosure piece 5 Winding 6 Support 7 Holder 8 Insulation 9 Individual wire 10 Marginal zone 11 Marginal zone 12 Insulation residue 13 Band piece 14 Insulation 15 Free end 16 Stamp 17 Stamp 18 Stamp 19 Stamp 20 Electrode 21 Electrode 22 Region 23 Edge 24 Edge 25 Arrangement 26 Contact surface 27 Contact surface 28 Contact surface 29 Contact surface d Thickness