Fuse, and method for manufacturing a fuse

Abstract

The invention relates to a fuse (1), in particular an SMD fuse, with an insulating body (2) open at the end face, at least one fusible conductor (3) arranged in the insulating body (2), at least one auxiliary cap (4) electrically contacting the fusible conductor (3) for covering the end face (5) of the insulating body (2) at least in some regions and an outer cap (6) allocated to the auxiliary cap (4) and covering same at least in some regions, preferably completely, and electrically contacting the auxiliary cap (4). According to the invention, the auxiliary cap (4) has a receptacle (8) which projects into the interior (7) of the insulating body (2) and has a through opening (9) projecting into the interior (7) of the insulating body (2), through which through opening the end region (10) of the fusible conductor (3) is guided; the end region (10) of the fusible conductor (3) is integrally connected in an electrically contacting manner to the auxiliary cap (4) via a preferably lead-free connection means (11) arranged in the receptacle (8); and the outer cap (6) covers the auxiliary cap (4) such that the connection means (11) is caught and / or encapsulated between the auxiliary cap (4) and the outer cap (6).

Description

[0001] Fuse and method for creating a fuse

[0002] The present invention relates to a fuse, in particular an SMD fuse and / or a device protection fuse, comprising an insulating body open at the end, at least one fusible element arranged in the insulating body, and at least one auxiliary cap electrically connected to the fusible element for at least partially covering the end face of the insulating body. An outer cap associated with the auxiliary cap, covering the auxiliary cap at least partially, and electrically connected to the auxiliary cap. Furthermore, the present invention relates to a method for producing a fuse of the aforementioned type.

[0003] A fuse or device protection fuse within the meaning of the present invention is also referred to in the prior art as a so-called "fuse link," which can interact with a fuse holder. The fuse link can be inserted into the fuse holder.

[0004] If necessary, the fuse or fuse link is filled with an extinguishing agent, in particular sand, granules, and / or glass beads, particularly with the extinguishing agent disposed within the insulating body. The insulating body can be designed as an insulating tube. In practice, the fusible element is inserted axially into the insulating body. The electrical contact between the fusible element and the outer contact caps attached to the insulating housing is established by a solder joint. Furthermore, the solder joint also firmly connects the outer contact caps to the insulating body.

[0005] The fusible element is designed to carry the full load current during operation and, in particular, to interrupt an overload current and / or short-circuit current as quickly as possible.

[0006] SMD fuses are fuse links that can be mounted on printed circuit boards (SMD - Surface Mounted Device). SMD fuses therefore belong to the technical field of surface mount technology (SMT). In surface mount technology, printed circuit boards are typically used as the surfaces to be assembled. SMD fuses, in particular, are standardized with regard to their dimensions and electrical behavior – see DIN EN 60127-4 VDE 0820-4:2013-12 (as of March 2023).

[0007] A disadvantage of prior art fuses is that in some fuses the fusible element shifts or moves within the insulating body during manufacture - after the fusible element has been inserted into the insulating body. Ultimately, the fusible element does not remain in its intended mounting position. This can result in the fusible element coming into contact with the inner wall of the insulating body or directly striking it. If the fusible element shifts in this way within the insulating body, the switching behavior of the entire fuse changes and, in particular, no longer corresponds to the designed values. This is extremely disadvantageous because every fuse is designed for specific values ​​and is used according to these values. Any deviation from the designed values ​​must therefore be avoided at all costs.

[0008] While fuses with a "displaced" fuse element can be rejected after manufacture using optical inspection methods, such a procedure is comparatively complex and expensive, particularly since a visual inspection of each individual fuse must be performed. Furthermore, due to the particularly opaque insulating body, this visual inspection can only be performed as long as the outer contact caps are not yet in place. However, if the fuse element is displaced after or during the installation of the outer contact caps, this can no longer be detected visually.

[0009] Another disadvantage of the fuse known from the prior art or of the method for manufacturing fuses known from the prior art is that the connection of the fusible element to the solder joint for electrically contacting the outer contact caps is often insufficient for a permanent electrical connection. For electrical contact between the fusible element and the outer contact cap, the formation of a so-called "solder ball" - a ball made of solder material - is required, but this does not always ensure a sufficient connection. For example, it can happen that the solder or solder material escapes into the space between the outer contact cap and the insulating body, and thus there is no longer enough solder for an adequate electrical connection between the fusible element and the outer contact caps.

[0010] The object of the present invention is therefore to avoid the aforementioned disadvantages of the prior art or at least to substantially reduce them. In particular, the object of the present invention is to ensure secure and permanent positioning of the fusible element in the insulating body.

[0011] According to the invention, the above-mentioned object is achieved by a fuse according to claim 1.

[0012] The fuse according to the invention is designed in particular as an SMD fuse or device protection fuse. The fuse has an insulating body that is open at the end—that is, in particular open at both end faces. At least one fusible element, which can also be designed as a fusible wire, is arranged in the insulating body. In addition, the fuse comprises at least one auxiliary cap that is electrically connected to the fusible element. The auxiliary cap is designed to cover at least part of the end face of the insulating body. In addition, the auxiliary cap is assigned an outer cap that covers the auxiliary cap at least part of the area, preferably completely, and is electrically connected to the auxiliary cap.

[0013] It is understood that a further auxiliary cap and / or a further outer cap may also be provided. In particular, the insulating body is covered on both of its end faces, first with an auxiliary cap and then with an outer cap. However, the present invention is not limited to two auxiliary caps and / or two outer caps and can be implemented with just one auxiliary cap and / or outer cap.

[0014] According to the invention, the auxiliary cap has a receptacle projecting into the interior of the insulating body and having a through-opening projecting into the interior of the insulating body. The end region of the fusible element can be passed through the through-opening, or in the finished state of the fuse, the fusible element is passed through the through-opening with its end region. The end region of the fusible element is electrically connected to the auxiliary cap via a connecting means, in particular a lead-free one, arranged in the receptacle. The outer cap covers the auxiliary cap in such a way that the connecting means is captured and / or encapsulated between the auxiliary cap and the outer cap.

[0015] The connecting means is arranged in the receptacle in such a way that it cannot enter the interior of the insulating body from the receptacle and / or escape via the outer cap. Particularly preferably, even if the connecting means subsequently melts and / or liquefies, penetration or escape of the connecting means into the interior of the insulating body can be at least substantially reliably prevented. Consequently, the connecting means is encapsulated in the receptacle.

[0016] In this context, it is understood that the receptacle can be partially or completely filled with the connecting element. Ultimately, the connecting element is arranged in the receptacle in such a way that the fusible element can be securely and permanently fixed.

[0017] Accordingly, the invention provides that the auxiliary cap, by means of the receptacle with a through-opening, provides a possibility of ensuring a simplified arrangement of the connecting means for permanent contacting of the fusible element.

[0018] The connecting means can have different shapes and / or structures. For example, the connecting means can be liquefied and / or melted to form a material-to-material connection with the fusible element. In particular, solder can be used as the connecting means. However, it can also be provided that the connecting means can be provided as a sheathing of the fusible element. This sheathing is then connected to the auxiliary cap in a material-to-material and / or electrically contacting manner.

[0019] The connecting means is particularly preferably also connected to the auxiliary cap and to the end region of the fusible element by a material fit. However, the connecting means can also be connected to the auxiliary cap in another way, in particular by a positive fit and / or friction fit. In particular, it is provided that the connecting means ultimately ensures the electrical connection between the fusible element and the auxiliary cap and also ensures the positioning of the fusible element.

[0020] The connecting element can ensure permanent electrical contact with the fusible element, while also ensuring a stable arrangement of the fusible element within the insulating body. The receptacle therefore provides a location for the connecting element and also allows the connecting element to remain only in a predefined and defined area within the fuse. This prevents the connecting element from, for example, penetrating the interior of the insulating body. The connecting element can, but does not have to, be connected to the outer cap. The electrical connection between the end region of the fusible element and the outer cap is achieved, in particular, via the auxiliary cap. The auxiliary cap therefore enables a comparatively simple arrangement of the connecting element and, in addition, simple contacting of the fusible element.

[0021] Although the receptacle has a through-opening, the auxiliary cap is particularly preferably designed to prevent the connecting means from escaping into the interior of the insulating body—and thus beyond the through-opening into the interior of the insulating body. In particular, the connecting means does not extend beyond the through-opening into the interior of the insulating body, so that the through-opening, despite being designed as an opening, represents a limitation for the connecting means. The auxiliary cap and the receptacle are designed in such a way that such penetration of the connecting means into the interior of the insulating body can be prevented. The through-opening therefore serves to pass through the end region of the fusible element, but not to pass through the connecting means.The secure fixation of the fusible element, which is ultimately achieved in particular by the connecting element, reliably prevents the element from leaning against the inner wall of the insulating body. The end section of the fusible element can be firmly and permanently fixed by the connecting element, and this fixation can withstand even high loads.

[0022] In a preferred embodiment, the fusible element terminates within the receptacle within the insulating body and / or is arranged without contact with the outer cap and / or the auxiliary cap. Particularly preferably, the fusible element does not directly adjoin a wall of the outer cap, the auxiliary cap, and / or the insulating body, whereby the electrical contact of the fusible element with the outer cap can ultimately be ensured by the arrangement of the connecting means in the auxiliary cap.

[0023] The aforementioned design ensures the long-term, proper use of the fuse. High levels of rejects during fuse production are particularly avoided because precise matching of the fuse element's contact with the auxiliary cap or outer cap is not required; instead, the electrical contact can be reliably and permanently ensured via the connecting element located in the holder.

[0024] Preferably, the length of the fusible element is less than or equal to the length of the insulating body. The fusible element can be arranged in the insulating body, in particular, in a straight, preferably elongated, state. In principle, however, it would also be possible in further embodiments for the fusible element to be provided in the insulating body, for example, wound on a winding body. In this case, the length of the fusible element would be greater than the length of the insulating body, although this is not necessarily feasible. A shorter length of the fusible element ensures that the material consumption of the fusible element is lower, which is sensible for economic reasons.

[0025] Particularly preferably, the end region of the fusible conductor is completely enclosed by the connecting means.

[0026] In further embodiments, at least a portion of the end region can also protrude beyond the connecting means, in particular so that not the entire end region of the fusible conductor is enclosed by the connecting means.

[0027] Completely enclosing the end of the fusible element with the connecting element can ensure that the fusible element is securely fixed and, in addition, long-term electrical contact with the end of the fusible element can be ensured. The connecting element therefore ensures that the fusible element is fixed in the insulating body.

[0028] In a further preferred embodiment of the invention, the connecting means is arranged exclusively in the region of the receptacle. The receptacle ultimately represents the area of ​​the fuse that can be used for the connecting means. The connecting means then has the function of securing the fusible element and electrically connecting it to the outer cap via the auxiliary cap. For this purpose, it is not necessary for the connecting means to be arranged outside the receptacle, so that, for reasons of material conservation, an arrangement only in the receptacle makes sense.

[0029] The through-opening preferably has an opening width of at least 0.1 mm. Particularly preferably, the opening width of the through-opening is between 0.1 mm and 6 mm, preferably between 0.5 mm and 5 mm, more preferably between 0.8 mm and 2.4 mm, and in particular between 1.1 mm and 1.5 mm. Through-opening widths in the aforementioned order of magnitude allow, on the one hand, the end region of the fusible element to pass through the through-opening and, on the other hand, prevent the connecting agent—even in the liquefied state—from escaping through the through-opening into the interior of the insulating body.

[0030] In a further embodiment, it is particularly preferred that the opening is designed as a V-shaped trough and / or as a truncated cone-shaped depression. A truncated cone-shaped depression or an at least substantially truncated cone-shaped depression can also be regarded as a trough. A truncated cone-shaped depression enables comparatively simple introduction and arrangement of the connecting means in the receptacle. The opening angle (i.e. in particular twice the angle between the surface line and the cone axis) of the depression, which is preferably designed as a truncated cone, is preferably between 10° and 100°, preferably between 20° and 90°, more preferably between 50° and 70°. This opening angle can thus ensure a trough that widens towards the end face of the insulating body.Such a trough shape offers the advantage that encapsulation of the connecting means can be achieved comparatively easily, since the trough tapers towards the interior of the insulating body, so that the connecting means is ultimately encapsulated in the receptacle.

[0031] In a further embodiment, it is particularly preferred that the connecting means located in the receptacle directly abut the inner wall of the outer cap facing the interior of the insulating body. In alternative embodiments, the connecting means may be arranged only indirectly on the outer cap and electrically contact the outer cap via the auxiliary cap.

[0032] A direct contact with the outer cap has the advantage that the connecting means can directly contact the outer cap electrically and thus, when current is carried, an electrical contact can be ensured directly between the outer cap, the connecting means and the fusible element and indirectly via the auxiliary cap, so that ultimately a "double protection" is provided.

[0033] In addition, the receptacle can be at least substantially completely filled with the connecting agent. Alternatively or additionally, it can be provided that at least 20%, preferably at least 30%, more preferably at least 40%, in particular between 30% and 80%, of the volume of the receptacle is filled with the connecting agent, in particular solder. Partially filling the receptacle offers the advantage, especially when using connecting agents with high material costs, that a small amount of the connecting agent can be provided. For example, connecting agents containing gold can also be used.

[0034] In a further preferred embodiment, it is provided that the outer cap is connected to the auxiliary cap via a press fit. Alternatively or additionally, it can be provided that the outer cap is connected to the auxiliary cap via at least one crimp connection, in particular via four crimp connections. A connection of the aforementioned type enables a firm adaptation of the outer cap to the auxiliary cap, in particular without the need for an additional adhesive connection or the like. Screwing, which could otherwise possibly damage the insulating housing, can also be avoided. The press fit and / or the crimp connection between the auxiliary cap and the outer cap can ensure a stable, in particular positive and / or frictional connection, which in particular can withstand the long-term stresses when used as a fuse.

[0035] The auxiliary cap preferably has a casing surface surrounding the wall of the insulating body. The auxiliary body can in particular be frictionally connected to the wall of the insulating body. Alternatively or additionally, it can be provided that the casing surface of the auxiliary cap has at least one, preferably circumferential, end-projecting locking leg, which is engaged behind by the outer cap. The locking leg can therefore serve to improve the attachment and connection of the outer cap. As a result, locking can particularly preferably be enabled. The casing surface can particularly preferably be formed in one piece. The locking leg is particularly preferably designed to surround the insulating body and protrude from the insulating body.

[0036] Furthermore, in a further preferred embodiment, the outer cap can be designed to completely cover the end face of the insulating body. The outer cap can thus protect the interior of the insulating body from external influences and thus ensure use as an SMD fuse. The outer cap preferably has an outer circumferential surface that at least indirectly surrounds the wall of the insulating body and is preferably frictionally connected to the circumferential surface of the inner auxiliary cap and at least indirectly, in particular frictionally connected, to the wall of the insulating body. Particularly preferably, the outer circumferential surface of the outer cap is locked to the locking leg of the auxiliary cap. The outer circumferential surface of the outer cap can in particular at least substantially completely cover or overlap the circumferential surface of the auxiliary cap, such that the auxiliary cap can be covered from the outside by the outer cap.The outer surface and the inner surface of the auxiliary cap can be electrically connected to one another, preferably by at least substantially directly abutting one another.

[0037] The connecting means can preferably comprise and / or consist of solder and / or an electrically conductive adhesive, in particular silver conductive adhesive, as a material. Alternatively or additionally, the connecting means can be designed as a conductive sheath, in particular a tin sheath, surrounding the end region of the fusible element. In this embodiment, it is understood that the tin sheath, in particular, can be regarded as a connecting means that can surround the end region of the fusible element, which in turn can be a wire. The tin sheath can then be designed to connect the fusible element wire and the auxiliary cap.

[0038] The connecting means can be used in different states or forms for connecting to the fusible element. For example, the connecting means, in particular the solder, can be in the form of a wire, as a solder paste, as a pellet, or as a molded part before melting. Alternatively or additionally, the solder can be provided to be lead-free. A lead-free design is particularly advantageous with regard to standards and specifications that must be adhered to. Ultimately, different forms of the connecting means can be used to electrically connect the end region of the fusible element to the auxiliary cap and / or the outer cap. However, the use of the connecting means as solder, which can be provided in different forms, is particularly preferred. What all connecting means have in common is that electrical contact with the fusible element can be ensured with a fixing connection of the fusible element to the auxiliary cap.Various materials that are commonly used in practice can be used as solder. Gold alloys, in particular, can also be used as solder.

[0039] In a further preferred embodiment of the inventive concept, the auxiliary cap has a bridging region connecting the outer surface to the receptacle. The bridging region can in particular rest at least partially on the end face of the wall of the insulating body and preferably protrude from this wall. Alternatively or additionally, it can be provided that the bridging region protrudes circumferentially from the wall of the insulating body. The bridging region, in combination with the formation of the trough, can thus ensure a bridge between the outer surface and the trough. The bridging region can also furthermore serve to bear against the outer cap and thus to make electrical contact with the outer cap. The bridging region thus ensures that different shapes for the trough can be provided, regardless of the formation of the outer surface.

[0040] Preferably, the receptacle can have a further opening opposite the through-opening projecting into the interior of the insulating body. The further opening can preferably be at least substantially circular. In particular, the area of ​​the further opening spans between 30% and 90%, preferably between 50% and 80%, more preferably between 60% and 75%, of the area of ​​the open end face of the insulating body. The through-opening can form the cover surface (i.e. the cut surface) and the further opening can form the base surface of the trough, which is preferably designed as a truncated cone. The area of ​​the through-opening can be smaller than the area of ​​the further opening. The fusible element can therefore be introduced into the interior first via the further opening and then via the through-opening. A trough jacket surface can then be arranged between the through-opening and the further opening, which trough the end region of the fusible element can adjoin.The trough can thus be formed and preferably limited by the trough shell surface, the through opening and the further opening.

[0041] In particular, the interior of the insulating body is at least partially filled with an extinguishing agent, in particular extinguishing sand. The extinguishing agent can be intended, in particular, to extinguish an arc.

[0042] The extinguishing agent may, in particular, comprise extinguishing sand with a preferably defined grain size distribution, which is preferably suitable for use in fire containment applications. Furthermore, colored sand, sand and / or ceramic chips, and / or glass beads may also be used as extinguishing agents.

[0043] Preferably, other materials can also be used for the extinguishing agent. However, the extinguishing agent is specifically designed to extinguish the arc in the event of a triggering event. Suitable materials can be used as the extinguishing agent for this purpose.

[0044] The insulating body can, in particular, be designed as an insulating tube. The fusible element can then preferably be inserted axially into the insulating body via the additional opening and the through-hole.

[0045] If sand is intended as the extinguishing agent, quartz sand is particularly preferred. As previously explained, the extinguishing agent allows an arc to be extinguished when the fuse is triggered, thereby increasing the safety and / or breaking capacity and / or breaking capacity of the entire fuse.

[0046] The fusible element can comprise and / or consist of an electrically conductive material, preferably metal. Materials used for the fusible element include, in particular, copper, nickel, steel, gold, and / or silver. Furthermore, the fusible element can comprise a metal alloy, for example, a silver and / or copper alloy. The fusible element can be designed as a fusible wire and / or a fusible strip. Furthermore, the fusible element can have an at least substantially circular and / or elliptical or at least substantially rectangular cross-section.

[0047] In addition, the fuse element can be provided with constrictions that allow for faster or slower overload and / or short-circuit response. These constrictions can then be designed, in particular, as cross-sectional constrictions.

[0048] In addition, the insulating body may comprise and / or consist of an electrically insulating material such as glass and / or ceramic.

[0049] Preferably, the fuse element can be completely enclosed within the insulating body, with external contact to the fuse element being possible via the outer caps. This can ensure easy installation of an SMD fuse on a circuit board.

[0050] In particular, the fusible element can be arranged centrally in the insulating body, which is particularly advantageous for the behavior of the fuse.

[0051] Alternatively or additionally, the insulating body may be made of and / or comprised of plastic. In particular, an electrically insulating material is provided as the material for the insulating body.

[0052] Preferably, a further auxiliary cap is provided which is connected in contact with the fusible element for at least partially covering the further end face of the insulating body, and a further outer cap is provided which is assigned to the further auxiliary cap and covers it at least partially, preferably completely, and is connected in electrical contact with the further auxiliary cap.

[0053] In this context, it is understood that with regard to the further auxiliary cap and / or the further outer cap, reference may be made to the aforementioned statements regarding the auxiliary cap and / or outer cap, since the further auxiliary cap and / or the further outer cap can also be provided with the previously discussed features. Finally, it is understood that two auxiliary caps and two outer caps can also be provided according to the aforementioned design.

[0054] It is particularly preferred that the auxiliary cap and the further auxiliary cap as well as the outer cap and the further outer cap are each at least substantially identical in design. However, the auxiliary cap and the further auxiliary cap or the outer cap and the further outer cap can also be designed differently from one another. In this case, the auxiliary cap and the outer cap as well as the further auxiliary cap and the further outer cap are preferably coordinated with one another so that electrical contact with the fusible element can be ensured via the respective outer cap. Even if the auxiliary cap and the further auxiliary cap or the outer cap and the further outer cap are designed differently, it is understood that reference may be made to the above-mentioned argument in this context as well, since these statements can be applied equally to the further auxiliary cap and the further outer cap.

[0055] Furthermore, the present invention relates to a method for producing a fuse according to one of the aforementioned embodiments, wherein the method comprises the following steps, which are preferably carried out successively:

[0056] A) Providing an insulating body, at least one auxiliary cap, at least one outer cap and at least one fusible element;

[0057] B) Placing the auxiliary cap on one end face of the insulating body;

[0058] C) Optional: Placing another auxiliary cap on another end face of the insulating body;

[0059] D) Inserting the fusible element into the interior of the insulating body, in particular via the through-hole of the auxiliary cap holder;

[0060] E) connecting the auxiliary cap to the fusible element by arranging the connecting means in the receptacle of the auxiliary cap for electrically connecting the auxiliary cap to the fusible element;

[0061] F) Optional: rotating the insulating body, in particular by 100° to 200°, preferably by approximately 180°;

[0062] G) Optional: Introduction of extinguishing agent, preferably via the not yet covered end face and / or via the additional receptacle of the additional auxiliary cap not yet filled with connecting agent; H) Covering the auxiliary cap with the outer cap for electrical contact.

[0063] In connection with the method according to the invention, reference may be made to the aforementioned preferred embodiments of the inventive securing device and to the advantages of the securing device, which equally apply to the method according to the invention, in particular without the need for further explicit mention. At the same time, the method features and advantages specified below also apply equally to the previously described inventive securing device. Accordingly, to avoid unnecessary repetition, reference is made to the following and previous statements.

[0064] In a particularly preferred embodiment of the method according to the invention, it is provided that the further auxiliary cap is connected to the fusible conductor, preferably after method step F and / or after method step G and / or H, by arranging the connecting means in the further receptacle of the further auxiliary cap for electrically connecting the further auxiliary cap to the fusible conductor.

[0065] In particular, the further auxiliary cap can be covered, preferably firmly connected, with the further outer cap for electronic contacting.

[0066] In addition, the connecting means can be heated, in particular melted, after being arranged in the receptacle, so that an electrical connection and a firm fixation between the connecting means and the fusible element and between the fusible element and the auxiliary cap are particularly preferably produced. In particular, the heating of the connecting means, which is particularly preferably already arranged in the receptacle, takes place by means of a flame, resistance soldering, laser soldering, hot air and / or induction. The aforementioned methods for heating the connecting means have proven to be particularly advantageous and precise in tests carried out during the development of the invention in order to ensure a secure connection. Alternatively or additionally, the connecting means, in particular the solder, can be in the form of a wire, as a solder paste, as a pellet or as a molded part before heating and / or before melting.

[0067] Furthermore, it is understood that the aforementioned intervals and range limits include any intermediate intervals and individual values ​​and are to be regarded as disclosed as essential to the invention, even if these intermediate intervals and individual values ​​are not specifically stated.

[0068] Further features, advantages and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings and the drawings themselves. All described and / or illustrated features, individually or in any combination, form the subject matter of the present invention, regardless of their summary in the claims or their reference back to them.

[0069] It shows:

[0070] Fig. 1 is a schematic perspective view of a fuse according to the invention,

[0071] Fig. 2 is a schematic perspective sectional view of the fuse shown in Fig. 1,

[0072] Fig. 3 is a further schematic sectional view of the fuse shown in Fig. 1,

[0073] Fig. 4 is a schematic perspective view of the fuse shown in Fig. 1 without outer cap,

[0074] Fig. 5 is a schematic perspective sectional view of the fuse shown in Fig. 4 without outer caps,

[0075] Fig. 6 is a further schematic sectional view of the fuse shown in Fig. 4 without outer caps,

[0076] Fig. 7 is a schematic perspective view of an auxiliary cap according to the invention,

[0077] Fig. 8 e is a schematic perspective sectional view of the auxiliary cap shown in Fig. 7, Fig. 9 is a further schematic sectional view of the auxiliary cap shown in Fig. 7 and

[0078] Fig. 10 is a schematic representation of a method according to the invention for producing a fuse according to the invention.

[0079] Fig. 1 shows a fuse 1, which can be designed in particular as an SMD fuse. The use as an SMD fuse is not shown in detail.

[0080] Figures 2 and 3 show cross-sectional views of the fuse 1 shown in Fig. 1.

[0081] Fig. 2 illustrates that the fuse 1 has an insulating body 2 that is open at one end. In the embodiment shown in Fig. 2, the insulating body 2 is open at both ends. Fig. 1 shows an at least substantially cuboid-shaped insulating body 2.

[0082] In further embodiments, different shapes can be used for this insulating body 2, for example a tubular design of the insulating body 2.

[0083] Figures 2 and 3 show that a fusible element 3 is arranged in the insulating body 2. The fusible element 3 can also be referred to as a fusible wire. In addition, an auxiliary cap 4 is provided, which is electrically connected to the fusible element 3. In the exemplary embodiments shown in Figs. 2 and 3, two auxiliary caps 4, 22 are provided, which are particularly preferably structurally identical to one another. It is not shown that only one auxiliary cap 4 can be used. The fuse 1 further comprises an outer cap 6. The outer cap 6 is assigned to the auxiliary cap 4 and covers or covers the auxiliary cap 4 at least in part, preferably completely. The outer cap 6 is electrically connected to the auxiliary cap 4. In addition, the auxiliary cap 4 covers the end face 5 of the insulating body at least in part, as shown in Fig. 3.

[0084] Fig. 4 shows the fuse illustrated in Fig. 1 without the outer caps 6. It is understood that two outer caps 6, 23 can also be used for the outer caps. In the illustrated embodiment, both outer caps 6, 23 are at least substantially identical in design. It is not shown that only one outer cap 6 can be provided.

[0085] Figs. 5 and 6 show cross-sectional views of the fuse 1 shown in Fig. 4 without the outer caps 6.

[0086] Fig. 2 shows that the auxiliary cap 4 has a receptacle 8 projecting into the interior 7 of the insulating body 2 with a through-opening 9 projecting into the interior of the insulating body 2, through which the end region 10 of the fusible element 3 is passed.

[0087] Fig. 3 again illustrates that the end region 10 of the fusible element 3 is electrically connected to the auxiliary cap 4 via a connecting means 11, in particular a lead-free one, arranged in the receptacle 8. The connecting means 11 is at least partially arranged in the receptacle 8. Fig. 2 shows that the receptacle 8 is at least substantially completely filled with the connecting means 11, although this is not absolutely necessary. The receptacle 8 without the connecting means 11 is shown in Fig. 7. Figures 8 and 9 show cross-sectional views of the auxiliary cap 4 shown in Fig. 4.

[0088] Fig. 2, but also Fig. 3, illustrates that the outer cap 6 covers the auxiliary cap 4 in such a way that the connecting means 11 is caught and / or encapsulated between the auxiliary cap 4 and the outer cap 6.

[0089] The connecting means 11 is arranged in the receptacle 8 in such a way that the connecting means 11 does not penetrate into the interior 7 of the insulating body 2—that is, beyond the through-opening 9 of the receptacle 8. The through-opening 9 represents, in particular, a boundary for the connecting means 11. The receptacle 8 is accordingly shaped or configured in such a way that encapsulation and / or capture of the connecting means 11 in the receptacle 8 can be ensured.

[0090] The connecting means 11 is particularly trapped and / or encapsulated in the receptacle 8 even when the fuse 1 is heated, and particularly preferably does not penetrate into the interior 7 of the insulating body 2 via the through-opening 9. Fig. 2 shows that the fusible element 3 ends in the receptacle 8 within the insulating body 2 and is also arranged without contact with the outer cap 6 and the auxiliary cap 4. In further embodiments, it can also be provided that the fusible element 3 rests against and / or strikes the auxiliary cap 4, the outer cap 6 and / or the receptacle 8. In the embodiment shown in Fig. 2, electrical contact with the fusible element 3 is ensured via the connecting means 11.

[0091] In the embodiment shown in Fig. 2, it is further provided that the length 12 of the fusible element 3 is less than or equal to the length 13 of the insulating body 2, which is also clearly illustrated in Fig. 6.

[0092] In further embodiments, it can also be provided that the length 12 of the fusible element 3 exceeds the length 13 of the insulating body 2, in particular if the fusible element 3 is provided wound in the insulating body 2. In the preferred and illustrated embodiment, an elongated fusible element 3 is provided. The fusible element 3 can have different shapes; for example, the fusible element 3 can be designed as a fusible element strip and / or as a fusible element wire, preferably having a circular and / or elliptical cross-section.

[0093] Fig. 2 illustrates that the end region 10 of the fusible element 2 is completely enclosed by the connecting means 11.

[0094] In further embodiments not shown in detail, it can also be provided that the receptacle 8 is not completely filled with the connecting means 11 and / or that the end region 10 of the fusible conductor 2 is not completely enclosed by the connecting means 11, in particular such that at least a section of the end region 10 of the fusible conductor 2 protrudes from or opposite the connecting means 11.

[0095] The connecting means 11 is arranged exclusively in the area of ​​the receptacle 8, which is also shown in Fig. 6.

[0096] Not shown in detail is that the through-opening 9 has an opening width 24 between 0.1 mm and 6 mm, preferably between 0.5 mm and 5 mm. The opening width 24 is shown, for example, in Fig. 6. Particularly preferably, the opening width 24 is between 1.1 and 1.5 mm.

[0097] Fig. 7 shows that the receptacle 8 is designed as a V-shaped recess and as a truncated cone-shaped depression. In particular, the opening angle a, which is shown, for example, in Fig. 9 and corresponds in particular to twice the angle between the generatrix of the truncated cone and the cone axis, can be between 20° and 90°, in particular between 50° and 70°.

[0098] The frustoconical recess is characterized by the fact that the two end faces (base surface and cover surface (also called cutting surface)) are open and the lateral surface is designed as a leg protruding from the bridging area 20.

[0099] Fig. 3 shows that the connecting means 11 located in the receptacle 8 lies directly against the inner wall 14 facing the interior 7 of the insulating body 2, in particular the inner wall 14 of the outer cap 6 resting on the open end face of the insulating body 2.

[0100] Fig. 3 shows that the receptacle 8 is at least substantially completely filled with the connecting means 11.

[0101] Not shown is that in further embodiments, the receptacle 8 can be only partially filled with the connecting means 11. The connecting means 11 is in particular formed in one piece. The connecting means 11 fills at least 20%, in particular at least 40%, of the volume of the receptacle 8.

[0102] The outer cap 6 can be connected to the auxiliary cap 4, for example, via a press fit and / or a crimp connection. In particular, the outer cap 6 is connected to the auxiliary cap 4 via at least one crimp connection, in particular via at least four crimp connections.

[0103] Fig. 14 shows that the auxiliary cap 4 has a circumferential surface 15 surrounding the wall of the insulating body 2. The circumferential surface 15 of the auxiliary cap 4 can be frictionally connected to the wall of the insulating body 2, which is also evident from Fig. 5. Furthermore, Fig. 4 shows that the circumferential surface 15 has at least one, preferably circumferential, protruding locking leg 16. The locking leg 16 can be engaged behind by the outer cap 6, as can be seen from Fig. 3.

[0104] Fig. 2 shows that the outer cap 6 is designed to completely cover the end face 5 of the insulating body 2. The outer cap 6 comprises an outer surface 17, which is also shown in Fig. 1. The outer surface 17 can at least indirectly rest against the wall of the insulating body 2 or at least indirectly surround the wall of the insulating body 2. In the exemplary embodiment shown in Fig. 3, the surface 15 of the auxiliary cap 4 is arranged between the wall of the insulating body 2 and the outer surface 17. The outer surface 17 can preferably be frictionally connected to the surface 15 of the auxiliary cap 4 and at least indirectly frictionally connected to the wall of the insulating body 2.

[0105] The connecting means 11 used in the illustrated embodiments can comprise and / or consist of solder as its material. Not shown is the possibility that an electrically conductive adhesive, in particular a silver conductive adhesive, can also be provided as the connecting means 11.

[0106] Furthermore, it is not shown that the connecting means 11 can also be formed by a sheathing of the fusible element 3, in particular a sheathing provided in the end region 10 of the fusible element 3. The sheathing can in particular be designed as a tin sheath.

[0107] Before melting, the connecting agent 11 can be in the form of a wire, a solder paste, a pellet, or a molded part. When using solder as the connecting agent 11, it is particularly preferred if the solder is lead-free.

[0108] Fig. 7 shows that the auxiliary cap 4 has a bridging region 20 connecting the outer surface 15 to the receptacle 8. The outer surface of the receptacle 8, in particular the outer surface of the frustoconical recess, can also adjoin the bridging region 20. The bridging region 20 can also delimit a further opening 21. The further opening 21 can be opposite the through-opening. The further opening 21 and the through-opening 9 can form the end faces of the trough or the receptacle 8. The bridging region 20 can rest at least partially on the end face 5 of the wall of the insulating body 2, as shown in Fig. 3. The bridging region 20 can also protrude from the wall of the insulating body 2, in particular with the bridging region 20 protruding circumferentially from the wall of the insulating body 2.

[0109] The further opening 21 can also be at least substantially circular, as shown in Fig. 7. The area of ​​the further opening 21 can span between 50% and 80% of the area of ​​the opened end face 5 of the insulating body 2.

[0110] It is not shown in more detail that the interior 7 of the insulating body 2 is at least partially filled with an extinguishing agent, in particular extinguishing sand.

[0111] It is also not shown in more detail that the insulating body 2 can have and / or consist of ceramic and / or plastic as material.

[0112] As already explained at the beginning, the figures show that, in addition to the auxiliary cap 4, a further auxiliary cap 22 is also provided, which is covered by a further outer cap 23. The further auxiliary cap 22 and the further outer cap 23 can be designed according to the features previously discussed in connection with the auxiliary cap 4 and the outer cap 6. Thus, the further auxiliary cap 22 can also be provided to at least partially cover the further end face 5 of the insulating body 2. The further outer cap 23 can be electrically connected to the further auxiliary cap 22 and cover it, preferably completely.

[0113] Fig. 10 shows a schematic process flow for producing a fuse 1 constructed according to one of the aforementioned embodiments. The process, as illustrated in Fig. 10, comprises steps A to H.

[0114] In step A, an insulating body 2, at least one auxiliary cap 4, at least one outer cap 6, and at least one fusible element 3 are provided. In the subsequent process step B, the auxiliary cap 4 is placed on an end face 5 of the insulating body 2.

[0115] Step C can be provided optionally and comprises placing a further auxiliary cap 22 onto a further end face 5 of the insulating body 2. After process step C, process step D is carried out. In step D, the fusible element 3 is inserted into the interior 7 of the insulating body 2. The fusible element 3 can be inserted via the through-opening 9 of the receptacle 8 of the auxiliary cap 4.

[0116] In method step E, it is provided that the auxiliary cap 4 is connected to the fusible element 3 by arranging the connecting means 11 in the receptacle 8 of the auxiliary cap 4 for electrically connecting the auxiliary cap 4 to the fusible element 3.

[0117] Steps F and G are optional. In step F, after performing step E, the insulating body 2 is rotated, in particular by 100° to 200°, preferably by approximately 180°. In optional process step G, extinguishing agent is introduced, preferably via the not yet covered end face 5 and / or the additional receptacle 8 of the additional auxiliary cap 22 not yet filled with the connecting agent 11. The extinguishing agent can be located in the interior 7 of the insulating body 2.

[0118] In process step H, the auxiliary cap 4 is covered with the outer cap 6 for electrical contact.

[0119] It is not shown that the further auxiliary cap 22, preferably after method step F and / or after method step G and / or H, is connected to the fusible element 3 by arranging the connecting means 11 in the further receptacle 8 of the further auxiliary cap 22 for electrically connecting the further auxiliary cap 22 to the fusible element 3, in particular wherein the further auxiliary cap 22 is covered with a further outer cap 23 for electrical contacting.

[0120] Furthermore, it is not shown that the connecting means 11 can be heated after being arranged in the receptacle 8. The heating can take place in particular by melting the connecting means 11. Such a heating step can be carried out in particular by means of a flame, resistance soldering, laser soldering, hot air and / or induction. Alternatively or additionally, it can be provided that the connecting means 11 is designed in wire form, as a solder paste, as a pellet and as a molded part before heating and / or before melting. Ultimately, the connecting means 11 can be provided in different forms and by melting or liquefying the connecting means 11, a permanent bond with the end region 10 of the fusible element 3 can be achieved.

[0121] List of reference symbols:

[0122] 1 fuse insulator fuse element auxiliary cap front side of 2 outer cap inner of 2

[0123] 8 Recording of 4

[0124] 9 Passage opening

[0125] 10 End area of ​​3

[0126] 11 connecting devices

[0127] 12 length of 3

[0128] 13 Length of 2

[0129] 14 inner wall of 6

[0130] 15 lateral surface of 4

[0131] 16 locking legs

[0132] 17 Outer surface

[0133] 18 length of 10

[0134] 19 depth of 8

[0135] 20 Bridging area

[0136] 21 further opening

[0137] 22 additional auxiliary caps

[0138] 23 additional outer cap

[0139] 24 Opening width a Opening angle

Claims

Patent claims:

1. Fuse (1), in particular an SMD fuse, with an insulating body (2) open at the end, at least one fusible element (3) arranged in the insulating body (2), at least one auxiliary cap (4) which is electrically connected to the fusible element (3) for covering at least part of the end face (5) of the insulating body (2), and an outer cap (6) which is assigned to the auxiliary cap (4) and covers the end face (5) of the insulating body (2) at least part of the way, preferably completely, and is electrically connected to the auxiliary cap (4), characterized in that the auxiliary cap (4) has a receptacle (8) which projects into the interior (7) of the insulating body (2) and has a through-opening (9) which projects into the interior (7) of the insulating body (2), through which the end region (10) of the fusible element (3) is passed, in that the end region (10) of the fusible element (3) is electrically connected to the auxiliary cap (4) via a lead-free, in particular lead-free,connecting means (11) is materially connected and that the outer cap (6) covers the auxiliary cap (4) in such a way that the connecting means (11) is caught and / or encapsulated between the auxiliary cap (4) and the outer cap (6).

2. Fuse according to claim 1, characterized in that the fusible element (3) ends in the receptacle (8) within the insulating body (2) and / or is arranged without contact with the outer cap (6) and / or the auxiliary cap (4) and / or that the length (12) of the fusible element (3) is less than or equal to the length (13) of the insulating body (2) and / or that the end region (10) of the fusible element (2) is completely enclosed by the connecting means (11).

3. Fuse according to claim 1 or 2, characterized in that the connecting means (11) is arranged exclusively in the region of the receptacle (8) and / or that the through-opening (9) has an opening width (24) between 0.1 mm to 6 mm, preferably between 0.5 mm to 5 mm, more preferably between 0.8 mm to 2.4 mm and in particular between 1.1 mm to 1.5 mm.

4. Fuse according to one of the preceding claims, characterized in that the receptacle (8) is formed as a V-shaped trough and / or as a frustoconical depression, in particular wherein the opening angle (a) of the receptacle (8) formed as a frustoconical depression is between 10° and 100°, preferably between 20° and 90°, more preferably between 50° and 70°.

5. Fuse according to one of the preceding claims, characterized in that the connecting means (11) located in the receptacle (8) lies directly against the inner wall (14) of the outer cap (6) facing the interior (7) of the insulating body (2).

6. Fuse according to one of the preceding claims, characterized in that the receptacle (8) is at least substantially completely filled with the connecting means (11) or that at least 20%, preferably at least 30%, more preferably at least 40%, of the volume of the receptacle (8) is filled with the connecting means (11), in particular solder.

7. Fuse according to one of the preceding claims, characterized in that the outer cap (6) is connected to the auxiliary cap (4) via a press fit and / or that the outer cap (6) is connected to the auxiliary cap (4) via at least one crimp connection, in particular via at least four crimp connections.

8. Fuse according to one of the preceding claims, characterized in that the auxiliary cap (4) has a jacket surface (15) surrounding the wall of the insulating body (2), in particular wherein the jacket surface (15) of the auxiliary cap (4) is frictionally connected to the wall of the insulating body (2) and / or in particular wherein the jacket surface (15) has at least one, preferably circumferential, end-projecting locking leg (16) which is engaged behind by the outer cap (6), and / or that the outer cap (6) is designed to completely cover the end face (5) of the insulating body (2) and preferably has an outer jacket surface (17) which at least indirectly surrounds the wall of the insulating body (2) and preferably frictionally connected to the outer surface (15) of the auxiliary cap (4) and at least indirectly frictionally connected to the wall of the insulating body (2).

9. Fuse according to one of the preceding claims, characterized in that the connecting means (11) has and / or consists of solder and / or an electrically conductive adhesive, in particular silver conductive adhesive, as material, or that the connecting means (11) is designed as a conductive sheath of the fusible element (3) surrounding the end region (10) of the fusible element (3), preferably as a tin sheath, and / or that the connecting means (11), preferably the solder, is designed in the form of a wire, as a solder paste, as a pellet or as a shaped part before melting and / or that the connecting means (11), preferably the solder, is lead-free.

10. Fuse according to one of the preceding claims, characterized in that the auxiliary cap (4) has a bridging region (20) connecting the jacket surface (15) to the receptacle (8), in particular wherein the bridging region (20) rests at least in regions on the end face (5) of the wall of the insulating body (2) and in particular preferably projects relative to this and / or in particular wherein the bridging region (20) projects circumferentially relative to the wall of the insulating body (2).

11. Fuse according to one of the preceding claims, characterized in that the receptacle (8) has a further opening (21) opposite the through opening (9) projecting into the interior (7) of the insulating body (2), which opening is preferably at least substantially circular, in particular wherein the area of ​​the further opening (21) spans between 30% to 90%, preferably between 50% to 80%, more preferably between 60% to 75%, of the area of ​​the open end face (5) of the insulating body (2).

12. Fuse according to one of the preceding claims, characterized in that the interior (7) of the insulating body (2) is at least partially filled with an extinguishing agent, in particular an extinguishing sand, and / or that the insulating body (2) has and / or consists of ceramic and / or plastic as material.

13. Fuse according to one of the preceding claims, characterized in that a further auxiliary cap (22) is provided which is connected in contact with the fusible element (3) for covering at least part of the further end face (5) of the insulating body (2) and a further outer cap (23) is provided which is assigned to the further auxiliary cap (22) and covers it at least part of the way, preferably completely, and is connected in electrical contact with the further auxiliary cap (22).

14. A method for producing a fuse (1) according to any one of the preceding claims, wherein the method comprises the following steps, which are preferably carried out successively: A) providing an insulating body (2), at least one auxiliary cap (4), at least one outer cap (6) and at least one fusible element (3); B) Placing the auxiliary cap (4) on one end face (5) of the insulating body (2); C) Optional: Placing a further auxiliary cap (22) on a further end face (5) of the insulating body (2); D) introducing the fusible element (3) into the interior (7) of the insulating body (2), in particular via the through-opening (9) of the receptacle (8) of the auxiliary cap (4); E) connecting the auxiliary cap (4) to the fusible element (3) by arranging the connecting means (11) in the receptacle (8) of the auxiliary cap (4) for electrically connecting the auxiliary cap (4) to the fusible element (3); F) Optionally: rotating the insulating body (2), in particular by 100° to 200°, preferably by approximately 180°; G) Optional: introduction of extinguishing agent, preferably via the front side (5) which is not yet covered and / or via the further receptacle (8) of the further auxiliary cap (22) which is not yet filled with connecting means (11); H) Cover the auxiliary cap (4) with the outer cap (6) for electrical contact.

15. Method according to claim 14, characterized in that the further auxiliary cap (22), preferably after method step F) and / or G) and / or H), is connected to the fusible conductor (3) by arranging the connecting means (11) in the further receptacle (8) of the further auxiliary cap (22) for electrically connecting the further auxiliary cap (22) to the fusible conductor (3) and / or that the further auxiliary cap (22) is covered with a further outer cap (23) for electrical contact.

16. The method according to claim 14 or 15, characterized in that the connecting means (11) is heated, in particular melted, after being arranged in the receptacle (8), in particular by means of a flame, resistance soldering, laser soldering, hot air and / or induction and / or that the connecting means (11), preferably the solder, is designed in wire form, as a solder paste, as a pellet or as a shaped part before heating and / or before melting.

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