Method for producing a safety device and safety device

Abstract

Method for producing a fuse device (1), in which respective conductor tracks (2) are electrically connected to one another by means of a fusible conductor (9), wherein - respective recesses (5) are produced at mutually facing conductor track end sections (6) of the conductor tracks (2); - respective longitudinal ends (10) of the fusible element (9) are arranged on the recesses (5) in such a way that they enclose the longitudinal ends (10) of the fusible element (9); - the longitudinal ends (10) of the fusible element (9) enclosed by the recesses (5) are melted and thereby integrally connected to the conductor track end sections (6), where the recesses (5) produced on the carrier element (3) are provided with a metallic coating (8) to which the longitudinal ends (10) of the fusible conductor (9) are integrally connected, characterized in that the recesses (5) are produced in such a way that the conductor track end sections (6) and / or the carrier element (3) surround the recesses (5) from three sides (7) each.

Description

The invention relates to a method for producing a securing device and to a securing device of the type specified in the preambles of the independent claims.Fuse devices in the form of fuses are known per se. In the case of fuse devices designed as a fuse, a circuit is interrupted by the melting of a fusible conductor if the current intensity exceeds a specific value for a sufficient time. Such safety devices are contacted, for example, with electrical lines of a motor vehicle on-board power supply system in order to protect such motor vehicle on-board power supplies from overloading.A fuse device designed as a fuse and a corresponding method for producing such a fuse device are shown, for example, in DE 198 57 299 A1. First, a substrate of copper is provided, which has two thick-walled portions and a thin-walled portion therebetween. Through holes are formed in the thin-wall portion, and a metal having a particularly low melting point is then inserted into the formed through holes and fused to the remaining substrate. Then, a part of the thin-wall portion which is interposed between the thick-wall portions of the substrate is punched out so that the thick-wall portions form contacts which are conductively connected to each other by the low melting point metal previously inserted into the through holes.In particular, in the case of securing devices used in the motor vehicle sector, for example in motor vehicle on-board power supply systems, the installation space for such securing devices can be relatively limited. On the one hand, such fuse devices should therefore be designed to be relatively compact and, on the other hand, it should additionally also be possible to reliably ensure that such fuse devices designed as fuses trigger reliably.The document JP H06-69 626 A relates to the provision of a reliable mounting structure for a circuit protection element which is formed compactly and is not scattered into the periphery during melting.The document DE 29 49 432 A1 relates to plug fuses having two parallel plug elements which are arranged at a distance from one another and are designed for receiving in spring terminals of a fuse panel, a fusible conductor extending between these plug elements, and a housing made of insulating material which receives part of each plug element and the fusible conductor.The document JP H08-315 719 A relates to providing a glass tube type fuse mounting structure which obviates the need for a fuse holder and is inexpensive.The document DE 30 35 665 A1 relates to a five-way fuse which is intended to have high reliability, thermal stability and high current cut-off performance.JP 2004-172 518 A relates to providing a circuit protection member that is further miniaturized than a conventional article, ensures quick protection, improves mass productivity and packaging property, and is also capable of coping with shutdown performance from a low voltage to a high voltage.The publication US 2008 / 0 278 276 A1 relates to a primary securing device for attachment to a printed circuit board.The document DE 10 2016 103 220 A1 relates to an electrical safety device and a method for producing an electrical safety device.It is therefore the object of the present invention to provide a method for producing a securing device and a securing device, by means of which a particularly reliable release of such a securing device can be made possible with at the same time particularly compact dimensions of the securing device.This object is achieved by a method for producing a securing device and by a securing device having the features of the independent patent claims. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims.In the method according to the invention for producing a fuse device, respective conductor tracks are electrically conductively connected to one another by means of a fusible conductor. The method according to the invention is distinguished in that respective recesses are produced at mutually facing conductor track end sections of the conductor tracks. Respective longitudinal ends of the fusible conductor are arranged at the recesses in such a way that they enclose the longitudinal ends of the fusible conductor. The longitudinal ends of the fusible conductor enclosed by the recesses are subsequently fused and thereby connected to the conductor track end sections in a materially bonded manner. The recesses produced on the carrier element are provided with a metallic coating, with which the longitudinal ends of the fusible conductor are connected in a materially bonded manner. The recesses are produced in such a way that the guide track end sections and / or the carrier element surround the recesses in each case from three sides.The fusible conductor has a substantially lower melting temperature than the conductor tracks. In this case, the fusible conductor can be designed, for example, as a wire, in particular a round or flat wire. In addition, the fusible conductor is preferably formed linearly and optionally flat, for example by (rolling) plating. The conductor tracks are preferably made of copper and the fusible conductor consists of an electrically conductive material which has a substantially lower melting temperature than copper. The recesses at the mutually facing conductor track end sections are preferably produced as through-openings. The recesses are produced in the conductor track end sections with regard to their shape in such a way that they substantially correspond to the shape of the end sections of the fusible conductor. This makes it possible to ensure that the fusible conductor can be introduced into the previously produced recesses of the conductor track end sections in a particularly precise manner. By subsequent melting of the correspondingly arranged fusible conductor, the latter is connected to the conductor track end sections in a materially bonded and thus reliable manner.The method according to the invention thus enables the production of a fuse device which has a fusible conductor between its conductor track end sections, which fusible conductor connects the two conductor track end sections to one another in an electrically conductive manner. Because the fusible conductor is introduced into the recesses in the conductor track end sections and is subsequently connected to the conductor track end sections in a materially bonded manner, a very compact construction of the safety device can be ensured with simultaneously reliable release characteristic of the safety device.An advantageous embodiment of the invention provides that the conductor tracks are produced on a carrier element and the recesses are produced both on the conductor track end sections and on the carrier element arranged beneath them. In other words, a carrier-based fuse is preferably produced. The carrier element can be, for example, conventional printed circuit board material in the form of FR-4 or the like. Because the conductor tracks are produced on the carrier element, more complex shapes in the conductor tracks can also be realized in a simple manner. For example, copper can first be applied to the carrier element and subsequently a part of the applied copper can be etched away from the carrier element, so that the conductor tracks remain on the carrier element. After the conductor tracks have been produced on the carrier element, the recesses are produced both on the conductor track end sections and on the carrier element arranged beneath them, for example by punching out the recesses both from the conductor track end sections and from the region of the carrier element beneath them. In other words, it is also possible for the recesses to form through-openings through the conductor track end sections and through the underlying carrier element.A further advantageous embodiment of the invention provides that at least the recesses produced on the carrier element are provided with a metallic coating. The melting and cohesive connection of the fusible conductor to the conductor track end sections and to the carrier element is thereby considerably promoted. In addition, this measure also makes it possible to provide conductor tracks on both sides of the carrier element and to connect these to the fusible conductor in a particularly simple manner in an electrically conductive manner. In addition, the heat conduction from the conductor tracks via the metallic coating as far as the fusible conductor is promoted by the coating of the recesses.According to a further advantageous embodiment of the invention, it is provided that copper is used as the metallic coating. It is advantageous per se if the same material is used as the metallic coating as in the case of the conductor tracks. The thermal behavior and the current conductivity of the metallic coating at the recesses and the conductor tracks are thereby substantially identical, which has a positive effect, among other things, on the triggering properties of the fuse device designed as a fuse and thus on its melting characteristic.In a further advantageous embodiment of the invention, it is provided that the fusible conductor is arranged flat in the recesses and soldered to the carrier element. In other words, the fusible conductor is thus arranged planar in the produced recesses. The fusible conductor preferably forms a straight connecting line between the two conductor track end sections, wherein the longitudinal ends of the fusible conductor are accommodated within the recesses of the conductor track end sections and are connected thereto in a materially integral manner. Because the fusible conductor is arranged flat, i.e. planar, in the recesses and soldered to the carrier element, preferably to the metallic coating on the recesses of the carrier element, the fusible conductor is accommodated in a particularly space-saving manner within the securing device. The fusible conductor has sufficient space to maintain correspondingly necessary minimum distances from the remaining carrier element and from a housing of the securing device. In addition, the fusible conductor can hang freely in any spatial position in a pre-formed manner and then tear off under the influence of gravity without touching the carrier element serving as a printed circuit board.In a further advantageous embodiment of the invention, it is provided that the longitudinal ends of the fusible conductor are arranged such deeply recessed in the recesses that the fusible conductor does not project beyond the printed circuit board formed from the conductor tracks and carrier element in the transverse direction of the printed circuit board. For example, the longitudinal ends of the fusible conductor can be arranged recessed sufficiently deeply into the recesses or pressed into them such that the fusible conductor terminates at least flush with the conductor tracks, i.e. does not project beyond the latter in the transverse direction of the printed circuit board. Alternatively, however, it is also possible for the longitudinal ends of the fusible conductor to be recessed so deeply into the recesses that the conductor tracks slightly project beyond the fusible conductor in the transverse direction of the printed circuit board. Thus, a particularly compact design of the fuse device is possible because the maximum transverse dimensions of the fuse device are not influenced by the inserted fusible conductor.A further advantageous embodiment of the invention provides that the recesses are dimensioned as press fits and the longitudinal ends of the fusible conductor are pressed into the recesses before the melting. In other words, the recesses are thus produced in such a way that they are somewhat narrower than the outer dimensions of the longitudinal ends of the fusible conductor, i.e. that the longitudinal ends are wider than the recesses. By pressing the longitudinal ends of the fusible conductor into the recesses dimensioned as press fits, cold deformation of the longitudinal ends of the fusible conductor thus takes place, as a result of which a particularly reliable connection can be produced between the longitudinal ends of the fusible conductor and the recesses. By pressing in the longitudinal ends of the fusible conductor, the shape thereof is therefore adapted to the shape of the cutouts, such that the longitudinal ends of the fusible conductor bear completely or at least already for the most part flat within the cutouts on corresponding sides or walls of the cutouts. During the subsequent melting of the longitudinal ends of the fusible conductor, these can be connected particularly reliably in a materially integral manner to the conductor track end sections and, if appropriate, additionally also to the coated recesses in the carrier element. Alternatively, it is also possible to dimension the recesses slightly larger than the longitudinal ends of the fusible conductor, i.e. as a clearance fit, by dimensioning the recesses slightly wider than the longitudinal ends of the fusible conductor. This would have the advantage that the insertion of the fusible conductor into the recesses is simpler, since only little or no effort is required for this purpose. In addition, in this case, the requirements for the positioning accuracy when arranging the fusible conductor ends in the recesses are relatively low. Preferably, a counterholder is positioned below the recesses, wherein the longitudinal ends of the fusible conductor arranged in the recesses are then pressed onto the counterholder, for example by means of a punch, and are thereby cold-deformed. As a result, the longitudinal ends of the fusible conductor expand and are placed against the walls of the recesses or pressed against them. Preferably, regardless of the type of fit of the recesses, a counterholder is always arranged below the recesses before the longitudinal ends of the fusible conductor are pressed or pressed into the recesses.Preferably, the longitudinal ends of the fusible conductor are pressed into the recesses by means of a punch. As a result, the longitudinal ends of the fusible conductor can be introduced into the recesses in a particularly simple manner and placed against corresponding walls of the recesses.According to a further advantageous embodiment of the invention, it is provided that the recesses are produced in such a way that the conductor track end sections and / or the carrier element surround the recesses in each case from three sides. For example, the recesses can be produced in such a way that, in a plan view of the printed circuit board, they form a type of U-shaped recess, with the result that the conductor track end sections are surrounded in each case by three sides of the recesses. However, other shapes of the recesses are also possible, wherein, as already mentioned, the recesses are preferably adapted with regard to their shape to the shape of the longitudinal ends of the fusible conductor, i.e. form a quasi negative shape of the longitudinal ends of the fusible conductor. As a result, the longitudinal ends of the fusible conductor can be fitted or pressed into the previously produced recesses in a particularly reliable manner in order to mechanically contact the longitudinal ends of the fusible conductor with the recesses already once before the longitudinal ends of the fusible conductor are fused.In a further advantageous embodiment of the invention, it is provided that the fusible conductor is cut to length from a tin wire, for example a round or flat wire. The tin wire can be provided, for example, in the form of an endless material, wherein the fuse element just required is cut from this tin wire to length, i.e. is cut from it. As a result, the fusible conductor can be provided in a particularly simple and cost-effective manner.According to a further advantageous embodiment of the invention, it is provided that the fusible conductor is produced in such a way that it encloses, preferably completely encloses, a core produced from a flux. In other words, a tin wire with internal flux is thus used. The flux present in the fusible conductor can prevent the actual fusible conductor material from being oxidized by the oxygen contained in the ambient air during the melting of the longitudinal ends of the fusible conductor. Furthermore, the flux can also prevent the fusible conductor from being oxidized during operation, in particular when the fusible conductor is heated by a corresponding current flow. Instead of a solid tin wire with flux applied on the surface, therefore, a tin wire with an inner core of flux is preferably used, wherein the flux can be, for example, commercially available solder. The internal flux is protected from environmental influences and cannot be flaked off or otherwise lost. When the fusible conductor begins to liquify, i.e. melt, the internal flux has already liquefied beforehand and thus sparkles in the interior of the fusible conductor, builds up a corresponding internal pressure and mechanically breaks up the material of the fusible conductor, which is pasty or already liquid as a result of melting or melting, together with the oxide layer, as a result of which the fusible conductor is interrupted as intended. Furthermore, it can also be provided that, in addition to the flux, other filling materials are also provided in the interior of the fusible conductor, which filling materials have a lower melting point than the fusible conductor. The function of the fusible conductor can also be ensured in the case of larger line and thus tin wire cross sections. In particular, a particularly reliable and reliable operation of the fusible conductor can also be ensured over longer product lives, since the flux is shielded from environmental influences and, in addition, cannot be separated from the fusible conductor. In addition, a particularly simple and thus favorable production of the fusible conductor itself results, since it is not necessary for the fusible conductor to be subsequently wetted with a flux.In a further advantageous embodiment of the invention, it is provided that, for melting the longitudinal ends of the fusible conductor, the fusible conductor is indirectly heated by introducing heat into the conductor tracks. Preferably, heat is introduced onto the conductor tracks close to the fusible conductor, namely in such a dosage that the fusible conductor fuses, but does not completely fuse through. For example, the thermal energy required for melting the longitudinal ends of the fusible conductor can be introduced by means of a soldering iron or else by means of a laser, in that the soldering iron or the laser is directed onto the conductor track end sections which enclose the recesses in which the ends of the fusible conductor are accommodated. The advantage of this procedure is that the conductor tracks have a substantially higher melting point than the fusible conductor itself, so that the melting of the longitudinal ends of the fusible conductor can be controlled substantially better in this way. This can prevent the fusible conductor from melting completely in an undesired manner, which could certainly happen if the thermal energy required for melting the fusible conductor were introduced directly at the fusible conductor. Due to the higher melting point of the conductor tracks, a particularly simple process for melting the fusible conductor ends can thus be made possible when heat is introduced into the conductor tracks. In particular, the conductor tracks can thereby also buffer a part of the heat introduced into these, whereby the process management during the melting of the fusible conductor ends is simplified.The inventive safety device comprises at least two conductor tracks which are electrically conductively connected to one another by means of a fusible conductor. The conductor tracks are arranged on a carrier element, wherein conductor track end sections of the conductor tracks facing each other and the carrier element arranged underneath have recesses which enclose respective longitudinal ends of the fusible conductor. The longitudinal ends of the fusible conductor are connected to the conductor track end sections in a materially integral manner in the region of the recesses. The recesses surround the conductor track end sections and / or the carrier element in each case from three sides. Advantageous embodiments of the method according to the invention are to be regarded as an advantageous embodiment of the securing device according to the invention. The fusible conductor is preferably of linear shape and is oriented at least substantially planar to the conductor tracks or is arranged offset inward in a direction transverse to the main plane of extension of the conductor tracks, such that the securing device can be of particularly narrow design in this transverse direction, that is to say transversely to the main plane of extension of the conductor tracks. The fusible conductor is preferably designed in the form of a type of straight connecting line which connects the conductor track end sections to one another. The dimensions of the securing device in the transverse direction are therefore not determined, or are hardly determined, by the fusible conductor.An advantageous embodiment of the inventive fuse device provides that a through-opening serving as free space for the fusible conductor is formed in the carrier element between the conductor track end sections, said through-opening being adjoined by the cutouts. If the fusible conductor is triggered during operation, i.e. melted down, it can hang freely in any spatial position because of the free space in the carrier element and then tear off due to the influence of gravity, without touching the carrier element serving as a printed circuit board.Finally, according to a further advantageous embodiment of the invention, it is provided that the recesses arranged on the carrier element are provided with a metallic coating, with which the longitudinal ends of the fusible conductor are connected in a materially bonded manner. Preferably, the metallic coating is copper, wherein the fusible conductor is made of tin. By means of a corresponding introduction of heat, the fusible conductor can therefore be fused at its ends without the metallic coating melting on the recesses of the carrier element. In other words, it is thus possible in a simple and controlled manner to solder the fusible conductor to the metallic coating at the recesses.Further advantages, features and details of the invention will become apparent from the following description of a preferred exemplary embodiment and with reference to the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.The drawing shows in: FIG. 1 shows a plan view of a securing device which has two conductor tracks which are arranged on a carrier material, wherein respective conductor track end sections facing one another have recesses facing one another; FIG. 2 shows a further plan view of the fuse device, wherein a fusible conductor of the fuse device has been arranged at the oppositely arranged recesses of the conductor track end sections; and FIG. 3 shows a further plan view of the securing device, wherein respective longitudinal ends of the fusible conductor, which are surrounded by the recesses, have been fused and have thereby been connected to the conductor track end sections in a materially bonded manner.In the figures, identical or functionally identical elements are provided with the same reference numerals.A securing device 1 is shown in a plan view in FIG. 1. The presently illustrated securing device 1 is not yet completely finished. In the case shown here, the securing device 1 comprises two conductor tracks 2 which are produced from copper and are arranged on a carrier element 3. In other words, the carrier element 3 is therefore a type of printed circuit board on which the two conductor tracks 2 have been produced. For the production of the conductor tracks 2, for example, the entire carrier element 3 can first be provided with a thin copper layer, wherein the applied copper is subsequently etched away in such a way that only the two conductor tracks 2 remain on the carrier element 3.A through-opening serving as a recess or free space 4 is produced in the carrier element 3, for example by punching out corresponding carrier element material from the carrier element 3 or by severing it in some other way. In the same or in a separate production step, recesses 5, which are formed as through openings, are produced on respective conductor track end sections 6 facing one another and on the carrier element 3 arranged underneath them. Through-opening means here that the free space 4 and the recesses 5 extend completely through the observation plane in the transverse direction of the securing device 1, i.e. perpendicularly into the observation plane according to the present illustration. The recesses 5 are formed only half-open with respect to the main plane of extension of the securing device 1. The recesses 5 can likewise be punched out of the conductor tracks 2 and the carrier element 3 in the region of the conductor track end sections 6 or can be separated out in some other way, for example.As can be seen, the recesses 5 are substantially U-shaped, wherein respective sides 7, which are therefore corresponding walls in the region of the recesses 5 both on the conductor tracks 2 and on the carrier element 3 arranged beneath them, are provided with a metallic coating 8 made of copper. In other words, the metallic coating 8 is therefore a type of edge metallization made of copper.FIG. 2 shows the securing device 1 in a further plan view, wherein in the case shown in the present case a fusible conductor 9, which is part of the securing device 1, has been pressed into the recesses 5. The recesses 5 serving as enclosures for the fusible conductor 9 in the region of the mutually facing conductor track end sections 6 are dimensioned as press fits. This means that the recesses 5 are thus dimensioned narrower than respective longitudinal ends 10 of the fusible conductor 9, which are inserted into the recesses 5. The longitudinal ends 10 of the fusible conductor 9 are first positioned above the recesses 5 and then pressed into the recesses 5 with a punch, not shown here. Because the longitudinal ends 10 are wider than the recesses 5, the longitudinal ends 10 are cold-formed during the pressing-in process into the recesses 5 and are thereby placed at least substantially flush on the three sides 7, in each case, more precisely on the metallic coating 8 of the recesses 5 produced from copper.As can be seen, the fusible conductor 9 is arranged flat in the recesses 5, i.e. inserted flatly into the recesses 5. The longitudinal ends 10 of the fusible conductor 9 are arranged recessed sufficiently deeply into the recesses 5 that the fusible conductor 9 does not project beyond the printed circuit board formed from the conductor tracks 2 and the carrier element 3 in the transverse direction of the printed circuit board, that is to say perpendicularly into the viewing planes in the present illustration. In other words, the fusible conductor 9 is pressed or pressed into the recesses 5 to such an extent that the fusible conductor 9 terminates at least flush with the conductor tracks 2 in the transverse direction or is even arranged slightly countersunk with respect to the conductor tracks 2. In this case, the fusible conductor 9 is preferably pressed with its longitudinal ends 10 into the recesses 5 in such a way that the fusible conductor 9 is then still straight and not curved. In the transverse direction of the fuse device 1, the fusible conductor 9 therefore also has a straight shape after the longitudinal ends 10 have been pressed in and therefore no longer influences the dimensions of the fuse device 1 in the transverse direction. The dimensions of the fuse device 1 in the transverse direction are therefore not influenced by the inserted fusible conductor 9. As a result, a particularly compact construction of the securing device 1 in the transverse direction can be realized.FIG. 3 shows the securing device 1 in a further plan view, wherein the longitudinal ends 10 of the fusible conductor 9 have been fused. After the longitudinal ends 10 of the fusible conductor 9 have been pressed into the recesses 5, the longitudinal ends 10 of the fusible conductor 9 surrounded by the recesses 5 or by the metallic coating 8 are melted and thereby connected to the conductor track end sections 6 in a materially bonded manner. In this case, the longitudinal ends 10 are bonded to the entire metallic coating 8, which has been produced in the region of the recesses 8.For melting the fusible conductor 9, more precisely for melting the longitudinal ends 10 of the fusible conductor 9, the fusible conductor 9 is heated not directly but only indirectly by introducing heat into the conductor tracks 2. The fusible conductor 9 made of tin has a substantially lower melting point than the conductor tracks 2 made of copper. Therefore, direct introduction of heat into the fusible conductor 9 would be difficult to control such that the fusible conductor 9 only fuses at its longitudinal ends 10, but the fusible conductor 9 does not completely fuse in this case.In order to meet this problem, it is therefore provided that the thermal energy required for melting the longitudinal ends 10 of the fusible conductor 9 is provided by introducing heat into the conductor tracks 2. For this purpose, heat is introduced close to the fusible conductor 9, i.e. close to the longitudinal ends 10 in the region of the conductor tracks 2, namely in such a way that the fusible conductor 9 starts to melt in the region of its longitudinal ends 10, but the fusible conductor 9 does not melt completely. For the introduction of the thermal energy, a type of soldering iron designed as a stamp can be used, for example, which is placed on the conductor tracks 2. Alternatively, it is also possible to use, for example, a laser by means of which respective laser beams are directed onto the two conductor tracks 2 in the vicinity of the longitudinal ends 10 of the fusible conductor 9. The location of the heat introduction can be spaced apart from the longitudinal ends 10 by 1 to 3 cm, for example. In particular when using a laser, the usually matt surface of the conductor tracks is advantageous, since these are produced from copper. Overall, therefore, the indirect heating of the longitudinal ends 10 of the fusible conductor 9 enables a particularly controlled introduction of heat into the fusible conductor 9 and thus a particularly metered and controlled melting of the longitudinal ends 10, such that the longitudinal ends 10 can be reliably connected to the conductor tracks 2 in a materially integral manner.The fuse device 1 shown here is a so-called fuse, wherein, at a sufficient current intensity over a corresponding duration, the fusible conductor 9 fuses and thereby triggers the fuse device 1. The securing device 1 also has a housing, not shown here, which encloses the carrier element 3 and the conductor tracks 2 from the outside. The safety device 1 can be used, for example, in a motor vehicle electrical system, wherein the safety device 1 is contacted, for example, with lines of the motor vehicle electrical system in order to protect the latter from thermal overloading.Because the fusible conductor 9 is soldered flat, i.e. flat, into the elongated metallized recesses 5 of the carrier element 3 serving as a printed circuit board, the fusible conductor 9 in combination with the through-opening serving as a free space 4 has sufficient space to maintain correspondingly necessary minimum distances from the carrier element 3 and the housing, not shown here, of the securing device 1. During the use of the fuse device 1, the fusible conductor 9 can thereby freely hang through in any spatial position and then tear off by the influence of gravity without touching the carrier element 3.Due to the described arrangement of the fusible conductor 9, it can be ensured that a corresponding heat emission from the fusible conductor 9 neither into the carrier element 3 nor into the housing of the securing device 1, not shown here, becomes too great, since correspondingly necessary minimum distances can be maintained. By the arrangement of the fusible conductor 9, destruction of the housing material and of the circuit board material of the carrier element 3 due to the action of heat is thus counteracted. Furthermore, a desired triggering characteristic of the fusible conductor 9 and thus of the securing device 1 can be ensured particularly reliably on account of the described arrangement of the fusible conductor 9.LIST OF REFERENCE CHARACTERS1 Fuse device 2 Conductor track 3 Carrier element 4 Free space 5 Cutout 6 Conductor track end section 7 Side 8 Metallic coating 9 Fusible conductor 10 Longitudinal end

Claims

Method for producing a fuse device (1), in which respective conductor tracks (2) are electrically conductively connected to one another by means of a fusible conductor (9), wherein - respective recesses (5) are produced on mutually facing conductor track end sections (6) of the conductor tracks (2); - respective longitudinal ends (10) of the fusible conductor (9) are arranged on the recesses (5) in such a way that they enclose the longitudinal ends (10) of the fusible conductor (9); the longitudinal ends (10) of the fusible conductor (9) enclosed by the recesses (5) are melted and thereby bonded to the conductor track end sections (6), wherein the recesses (5) produced on the carrier element (3) are provided with a metallic coating (8), to which the longitudinal ends (10) of the fusible conductor (9) are bonded, characterized in that the recesses (5) are produced in such a way that the conductor track end sections (6) and / or the carrier element (3) each surround the recesses (5) from three sides (7).Method according to Claim 1, characterized in that the conductor tracks (2) are produced on a carrier element (3) and the cutouts (5) are produced both on the conductor track end sections (6) and on the carrier element (3) arranged beneath them.Method according to Claim 1 or 2, characterized in that copper is used as the metallic coating (8).Method according to one of the preceding claims, characterized in that the fusible conductor (9) is arranged flat in the recesses (5) and soldered to the carrier element (3).Method according to one of the preceding claims, characterized in that the longitudinal ends (10) of the fusible conductor (9) are arranged such that they are recessed sufficiently deeply into the recesses (5) that the fusible conductor (9) does not project beyond the printed circuit board formed from the conductor tracks (2) and the carrier element (3) in the transverse direction of the printed circuit board.Method according to one of the preceding claims, characterized in that the recesses (5) are dimensioned as press fits and the longitudinal ends (10) of the fusible conductor (9) are pressed into the recesses (5) before the melting.Method according to claim 6, characterised in that the longitudinal ends (10) of the fusible conductor (9) are pressed into the recesses (5) by means of a punch.Method according to one of the preceding claims, characterized in that the fusible conductor (9) is cut to length from a tin wire.Method according to one of the preceding claims, characterized in that the fusible conductor (9) is produced in such a way that it encloses a core produced from a flux.Method according to one of the preceding claims, characterized in that, in order to melt the longitudinal ends (10) of the fusible conductor (9), the latter is heated indirectly by introducing heat into the conductor tracks (2).Fuse device (1) having at least two conductor tracks (2) which are electrically conductively connected to one another by means of a fusible conductor (9), wherein - the conductor tracks (2) are arranged on a carrier element (3); - mutually facing conductor track end sections (6) of the conductor tracks (2) and the carrier element (3) arranged beneath them have recesses (5) which enclose respective longitudinal ends (10) of the fusible conductor (9); - the longitudinal ends (10) of the fusible conductor (9) are connected to the conductor track end sections (6) in a materially bonded manner in the region of the recesses (5), wherein the recesses (5) arranged on the carrier element (3) are provided with a metallic coating (8) to which the longitudinal ends (10) of the fusible conductor (9) are connected in a materially bonded manner, characterized in that the recesses (5) surround the conductor track end sections (6) and / or the carrier element (3) in each case by three sides (7).Fuse device (1) according to Claim 11, characterized in that a through-opening serving as free space (4) for the fusible conductor (9) is formed in the carrier element (3) between the conductor track end sections (6), said through-opening being adjoined by the cutouts (5).

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