DE202017006915U1 - fuse - Google Patents

Abstract

Fuse (1), preferably low-voltage fuse, preferably intended for use for a rated voltage range of greater than or equal to 900 V and / or for a rated current strength range of greater than or equal to 250 A, in particular for use in DC circuits, with an insulating body (2) and at least a strip-shaped fusible conductor (3), wherein the insulating body (2) has a receiving area (4) for receiving the fusible conductor (3), characterized in that the receiving area (4) has an at least substantially rectangular or rectangular shape in the cross section perpendicular to its longitudinal axis with diagonals extending between the corner regions (5) and that the fusible conductor (3) is arranged at least substantially in a diagonal plane of the receiving region (4).

Description

The invention relates to a fuse, preferably low-voltage fuse, preferably provided for use for a rated voltage range of greater than or equal to 900 V and / or for a rated current strength range of greater than or equal to 250 A, in particular for use in DC circuits, with an insulating body and with at least one strip-shaped Melting conductor, wherein the insulating body has a receiving area for receiving the fusible conductor.

A backup of the aforementioned type is already out of the DE 10 2014 212 068 A1 known. The known fuse has an outside square and inside round insulating. In the receiving area a plurality of fusible conductors are provided, which may have different arrangements. A disadvantage of the known fuse is that it can lead to damage of the insulator associated with the escape of hot sand from the insulator or even arcing in case of overload and short circuit. The above problem arises in particular with fuses for a high rated voltage range and / or a high rated current strength range.

From the DE 10 2012 210 292 A1 a fuse arrangement is known in which the receiving region of the insulating body is at least substantially rectangular. However, the individual fuse elements are arranged in a round recess of the insulating body. The fusible elements themselves are arranged at a distance from the recess.

Object of the present invention is to provide a fuse of the type mentioned above, which is as small as possible especially when used for a high rated voltage range and / or a high rated current range, while ensuring that it is at overload and especially in the Short circuit case if possible not to damage the insulating body, in particular associated with the escape of hot sand or even to an arc outlet comes.

The above object is achieved by a fuse with the features of the subject of claim 1. Advantageous developments are the subject of the dependent claims.

The invention relates to various investigations of fuses, in particular as known from the DE 10 2014 212 068 A1 are known, preceded. In such a known fuse melts at a load above a predetermined time / current range at least one arranged in the fuse fuse inside the fuse to ultimately separate the circuit. At the point of separation, a switching arc usually occurs, the extent and duration of which depend on the characteristics of the circuit with respect to the voltage, the current, the time constant of the fault circuit and the presence of AC or DC voltage. For rapid erasing of the arc, the known fuse is filled with an arc extinguishing agent surrounding the fusible conductor, which is typically quartz sand. As a result of the prevailing temperatures in the region of the arc, a non-conductive, fulgurite-like sintered body develops from the quartz sand surrounding the melt conductor. The fault current is interrupted.

In investigations of the sintered body has been found that its cross section is substantially larger than that of the fusible conductor. For example, a strip-shaped fusible conductor having a cross-sectional area of 20 × 0.2 mm can easily lead to the formation of a sintered body having dimensions of 30 × 10 mm in cross section. In a plurality of fusible conductors, as in the from DE 10 2014 212 068 A1 known fuse is the case, the fusible leads are comparatively close to the housing inner wall of the insulating introduced. It has then been found that, when triggered, the occurring high temperatures, which can be quite a few thousand degrees Celsius, especially at high rated currents and a larger cross-section of the fusible conductor in this context can lead to further enlargement of a sintered body and thus stress cracks of the insulating body, which can lead to the emergence in practice of hot sand or even arc escapes.

At the conclusion of the invention, it was then first tried to strengthen the insulator to avoid stress cracks. The reinforcement, however, has proven to be costly. Furthermore, the approach has been taken to increase the receiving space to have a greater distance of the fuse element to the inner wall of the insulating body. However, this can lead to an increase in the dimensions of the insulating body and thus the fuse. Incidentally, it has been considered to change the dimensions of the fusible elements so that they have a smaller width and therefore a slightly greater thickness for the same cross-sectional area. This also ultimately leads to a greater spacing of at least the ends of the fusible conductor to the inner wall of the insulating body. In this connection, however, it has been found that somewhat thicker fusible link ultimately adversely affect the response of the fuse.

The invention now goes another way.

The fuse according to the invention has a receiving region which has an at least substantially rectangular or rectangular shape in the cross section perpendicular to its longitudinal axis. Between each opposite corner regions of the receiving area extend diagonals of the receiving area. The strip-shaped fuse element is now arranged at least substantially in a diagonal plane of the receiving region. The arrangement on or in the region of the diagonal plane means in particular that one or more fusible conductors are preferably arranged only in the diagonal plane or, if necessary, in both diagonal planes and not outside the diagonal plane. In further embodiments, in addition to at least one fusible conductor, which is arranged at least substantially in a diagonal plane of the receiving area, at least one further fusible conductor may be provided, which is not arranged in a diagonal plane of the receiving area. Compared to a cylindrical receiving area with a round cross-section is due to the rectangular or rectangular shape of the receiving area in the corner areas an increased space for a hot sintered body, if this arises in the case of triggering in the region of the fusible conductor and its surroundings. Accordingly, a single fusible conductor extends in its widthwise extension in particular diagonally from corner to corner of the rectangular or rectangular receiving area. By arranging the fusible conductor on the diagonal plane of the rectangular or rectangular receiving area of the available space is optimally utilized. This is just the advantage of the solution according to the invention over a receiving area with a round cross-section, i. without trained corner areas.

The properties of the fuse according to the invention have a particularly advantageous effect if, instead of a single fusible conductor, a plurality of fusible conductors is provided. Here, preferably, up to four fusible conductors are arranged at least substantially in at least one diagonal plane of the receiving region. In the case of four fusible conductors, it is preferable in this case for two fusible conductors to be arranged in each case on one of the two diagonal planes, so that the result is a star-shaped arrangement of the fusible conductors in cross section. In comparison with a frequently provided in known fuses multiple parallel arrangement of fusible conductors or an arrangement of multiple fusible elements according to a square in cross-section basic pattern results from the inventive arrangement the advantage that at most only a punctual proximity of a resulting sintered body at the fusible edge to the often consists of relatively thick-walled corners of the insulator. The sides of the receiving area, that is, the longitudinal surfaces of the inner wall of the insulating body, have no proximity to the sintered body.

In a further preferred embodiment, up to eight fusible conductors are provided, it being preferred that in each case four fusible conductors are arranged on one of the two diagonal planes, so that the result is a star-shaped arrangement of the fusible conductors, in particular analogously to the use of four fusible conductors in the Cross section results. Preferably, two fusible conductors are arranged one behind the other on one leg of the star, so that in particular the star has four legs, each with two fusible conductors per leg. In particular, the heat output can be improved due to this embodiment. In the end, it goes without saying that in principle a plurality of fusible conductors can be provided in the two diagonal planes, wherein preferably the number of fusible conductors on one of the two diagonal planes is selected to be identical. Furthermore, it is advantageously such that in a star-shaped arrangement of the fusible conductor in cross-section, the legs of the star each have the same number of fusible conductors, wherein the star-shaped arrangement has four legs.

The advantage of an enlarged or rectangular or rectangular cross-sectional profile is particularly effective when the width of the fusible conductor is less than or equal to the radius of the inscribed circle of the rectangular or rectangular cross-sectional profile of the receiving area. A resulting, hot sintered body, which forms along or in the region of the fusible conductor, can expand in the radial direction into the corner region of the rectangular or rectangular receiving region, so that no planar heating of the housing wall of the insulating body takes place, but the high temperatures of the arc or At most, the sintered body act selectively on the housing corners of the insulating body. Particularly preferably, the distance of the fusible conductor to the inner wall and the housing corners is at least 3 mm.

In a particularly preferred embodiment of the fuse according to the invention, the receiving area has a square or square cross-sectional shape. The sides of the receiving area are formed in this case at least substantially the same length. A square or square-like cross-section of the receiving area allows an arrangement of a plurality of fusible conductors, in which the fusible conductor in uniform angles are arranged to each other. In particular, for a resulting sintered body is in such an arrangement, an increased space not only along the diagonal planes in the corner regions of the receiving area inside, but also between the fusible elements themselves. It comes so even with a strong thickness growth of the sintered body only in the edge region of the fusible conductor in the middle in the insulating body to a touch of the sintered body adjacent fusible link.

It is advantageous if the sides of the receiving area have a section in the shape of a curve in the form of a section of a section. Preferably, therefore, at least one side of the rectangular receiving area is arc-shaped, in particular arc-shaped, formed. This is particularly preferably the case with two in particular opposite sides or even on all sides. As a result, the volume of the receiving area is further increased.

With regard to a symmetrical design of the receiving area, it is advantageous if opposite sides of the receiving area each have the same radii of curvature. In particular, in the case of a square or square-shaped cross section of the receiving area, it is preferred that all sides have an identical radius of curvature.

Generally, the radius of curvature of one side preferably corresponds to its width. In particular, the curvature radius also increases with the side length. The ratio of radius of curvature and side length may be proportional, but both values may be in a different relationship with each other.

In a particularly preferred embodiment, the transition region between two adjacent sides of the receiving region is rounded and preferably has a smaller radius of curvature than the adjacent or adjacent sides. This is supported in particular by a curved-section-shaped form of the adjacent sides, since the curvature of one side can pass directly into the curvature of the corner region. As a result, the stability of the insulating body can be further increased. In contrast to a tapering corner region, in the aforementioned preferred embodiment, the insulating body can absorb higher internal pressure forces in the transitional region between two sides of the receiving region or divert forces occurring more uniformly over the surface of the inner wall. In addition, the insulating body in the corner region of the receiving area has a greater material thickness than would be the case with a tapered corner region.

In a preferred embodiment of the fuse according to the invention, the insulating body in the vertical to its longitudinal axis cross-section on the outside an at least substantially rectangular or rectangular shape. In conjunction with a rounded configuration of the inner corner regions, the insulating body thereby has at its corners a particularly high wall thickness. In the case of the fuse according to the invention, this is the region of the insulating body which comes closest to the fusible conductors and thus possibly to the hot sintered body. Due to the high material thickness in this area, the stability of the insulating body is thus increased, especially at critical points.

The fusible conductor is usually made of an electrically highly conductive material or has such. In particular, silver has particularly suitable properties in this regard.

In order to ensure premature and defined melting of the fusible conductor at too high a current flow, the fusible conductor in the fuse according to the invention preferably has a solder whose melting point is in particular lower than the melting point of the other materials of the fusible conductor, in particular of the decisive material for electrical conductivity , such as silver.

The individual fusible conductor preferably has at least one constriction, in particular in the form of a constriction web, with a reduced cross-section of the conductor. In case of overload or short circuit, due to the higher current density, a strong increase of the temperature above the melting range occurs first in the area of such a bottleneck and thus melting of the fusible conductor.

In a particularly preferred embodiment, the fusible conductor has one or more bottleneck rows each having a plurality of bottlenecks, by which the fusible conductor is ultimately segmented. In case of overload, the current density in the other bottlenecks of the same bottleneck row increases after the melting of a first throat web in one of the bottleneck rows. This continues with each further melting throat bridge until it completely breaks the fusible conductor. In the case of a short circuit, the current increases so rapidly that it comes to almost simultaneous evaporation of all bottlenecks of the bottleneck row. Depending on the magnitude of the fault current, several bottleneck rows can evaporate. Finally, the number of bottleneck rows determines the rated voltage of the fuse. At the rated voltage then in particular all bottleneck rows evaporate.

If more than one fusible conductor is provided, with the interruption of the current flow through the already interrupted fusible conductor, the current strength and thus also the current density in the other, remaining fusible leads increase, whereby in the area of the bottlenecks of the still intact fusible leads, too, gradually fuses comes. When the last of the intended fusible links is completely interrupted, the arc occurs, which again causes a current flow between the separate sections of a fusible conductor. The behavior described above occurs in this case at all broken bottleneck rows of the or the fusible conductor until the arc-cooling quartz sand enters into an insulating sintered body with the metal vapor.

In order to prevent propagation of the arc over all rows of bottlenecks and a possible strike-through of the arc, the receiving area is preferably filled with an arc extinguishing agent, which surrounds the fuse element or the. Sand in particular, preferably quartz sand, is a suitable material for this purpose. In the area of the arc, due to the high temperatures, sintering of the arc extinguishing agent now occurs, as a result of which the insulating sintered body described above is produced.

As a result of the aforementioned propagation or propagation of the arc in the event of triggering, the sintered body also grows over a certain area along the fusible conductor, that is to say in the axial direction. Due to the volume increase of the sintered body in the receiving area, which occurs both in the axial and in the radial direction, the hot material of the sintered body gets closer to the inner wall of the insulating body. A consequently occurring surface heating of the housing wall of the insulating body can ultimately lead to damage in the form of cracking or bursting.

This is where the invention finally comes in, by which the sintered body is given a larger volume into which it can expand. Furthermore, the insulating body is better protected by a greater spacing from the broad side of the fusible conductor and the arc occurring in the region of the fusible conductor in the event of triggering the occurring high temperatures, which may also have a damaging effect.

In the fuse according to the invention in particular flange plates are provided for external contacting of the fuse end. The flange plates are electrically connected inside the fuse with the fusible conductor and, in comparison to the fusible conductor, generally have a greater material thickness for a lower current density.

Especially with a shutdown of fault currents under DC voltage, the arc also develops in the axial direction of the fusible conductor and can reach into the region of the contact point between the enamel conductor end and flange plate. In this case, it can penetrate the flange plate in the extreme case and even escape from the flange plate to the outside and cause damage in the vicinity of the fuse. To avoid such an arc outlet, an electrically insulating material is provided in a preferred embodiment of the fuse according to the invention in the connection region of the fusible conductor with the flange plates and / or on the fusible conductor itself. Particularly suitable in this context is silicone, which, due to its gelatinous or pasty consistency, can be applied in the form of beads of material in the region of the contact point and / or on the melt conductor.

In the case of a plurality of fusible conductors, a star-shaped arrangement, as described above, entails the advantage that an application of the aforementioned silicone beads or of another insulating material in the region of the contact point between the fusible conductor and the flange plate and / or on the fusible conductor also after the completion of the fuse link from one or more flange plates and the fusible conductors is possible.

In a further preferred embodiment it is provided that at least one further fusible conductor is arranged in a gap, wherein the gap between two diagonals extending to the corner regions results. Most preferably, up to four fusible conductors are arranged at least substantially in the receiving region, preferably so that in each case two fusible conductors are arranged on a diagonal plane, in particular wherein the at least one further fusible conductor between two fusible conductors, that is in particular in which between two adjacent fusible conductors resulting gap, is provided. Preferably, four more fusible conductors are provided, so that preferably results in the cross-section of the shape of an eight-legged star. Preferably, therefore, the rated current can be increased. In particular, it is provided that the fusible conductor and the further fusible conductor have an at least substantially the same distance from the wall or to the inner wall of the insulating body and / or the housing corners. Furthermore, it is provided in a further preferred embodiment that the further fusible conductor has a different, preferably smaller width than the fusible conductor, in particular wherein the further fusible conductor less than 80%, preferably less than 70%, more preferably less than 60% and in particular at least substantially 50%, the width of the fusible conductor has.

In further embodiments it can be provided that the at least one further fusible conductor has at least substantially the same width as the fusible conductor. In addition, it may be provided in the case of a plurality of further fusible conductors that the other fusible conductors differ from each other in their width. Preferably, the fusible conductors and / or the further fusible conductors are arranged so that the arrangement in the cross-sectional representation is mirror-symmetrical with respect to a vertical and / or horizontal line.

Preferably, the fusible conductor has a width in the range from 5 to 50 mm, preferably from 5 to 40 mm, more preferably from 10 to 30 mm. If, in a preferred embodiment, four fusible conductors are arranged in each case in one of the two diagonal planes, ie a total of eight fusible conductors are arranged in the receiving region, it is preferably provided that a fusible conductor has a width of 5 to 15 mm, preferably of at least substantially 10 mm , having. If, in a further preferred embodiment, two fusible conductors are arranged in each of the two diagonal planes, then it is preferably provided that a fusible conductor has a width in the range of 10 to 25 mm, preferably of at least substantially 20 mm. If at least one further fusible conductor is arranged in the intermediate spaces between the diagonals, it is preferably provided that the further fusible conductor has a width in the range from 5 to 20 mm, preferably from 5 to 15 mm, more preferably from 8 to 12 mm, more preferably further from 8 to 10 mm, in particular wherein the further fusible conductor is arranged between the intermediate space in two adjacent fusible conductors.

Furthermore, in a further preferred embodiment it is provided that the further fusible conductors have a smaller width, as stated above, than the fusible conductors and / or have a larger distance to the center of the receiving area than the fusible conductors. The center of the receiving area can be in other embodiments, the center of the star-shaped arrangement of the fuse element in cross section.

Other features, advantages and applications of the present invention will become apparent from the following description of embodiments with reference to the drawings and the drawing itself. In this case, all described and / or illustrated features alone or in any combination, the subject of the present invention, regardless of yours Summary in the claims or their dependency.

• 1 eine schematische Querschnittsdarstellung einer bevorzugten Ausführungsform einer erfindungsgemäßen Sicherung,
• 2a eine schematische Querschnittsdarstellung einer bekannten Sicherung im Vergleich zur erfindungsgemäßen Sicherung aus 1,
• 2b eine schematische Querschnittsdarstellung einer weiteren Ausführungsform der erfindungsgemäßen Sicherung,
• 3 eine schematische Querschnittsdarstellung einer alternativen Ausführungsform der erfindungsgemäßen Sicherung,
• 4 einen Schmelzleiter in Draufsicht,
• 5 eine schematische Längsquerschnittsdarstellung der Sicherung aus 1 und
• 6 eine schematische Querschnittdarstellung einer alternativen Ausführungsform der erfindungsgemäßen Sicherung.

It shows

• 1 a schematic cross-sectional view of a preferred embodiment of a fuse according to the invention,
• 2a a schematic cross-sectional view of a known fuse in comparison to the fuse according to the invention 1 .
• 2 B a schematic cross-sectional view of another embodiment of the fuse according to the invention,
• 3 a schematic cross-sectional view of an alternative embodiment of the fuse according to the invention,
• 4 a fusible conductor in plan view,
• 5 a schematic longitudinal cross-sectional view of the fuse 1 and
• 6 a schematic cross-sectional view of an alternative embodiment of the fuse according to the invention.

A preferred embodiment of a fuse according to the invention 1 is in 1 shown in cross section. The cutting plane is perpendicular to the longitudinal axis of the fuse 1 and is in the side view of the fuse 1 according to 5 located.

The exterior of the fuse 1 is from an insulating body 2 educated. The insulator 2 consists in the present case of a ceramic material which has good electrical insulation properties. The electrically conductive connection through the fuse 1 is in the example shown by four internal fusible link 3 allows in a recording area 4 of the insulating body 2 are arranged.

The recording area 4 Incidentally, with an arc extinguishing agent, not shown, which is particularly preferably sand, in particular quartz sand, preferably extends over almost the entire length of the insulating body 2 and has in the cross section shown here a rectangular or even square-like shape. According to the between opposite corner areas 5 of the recording area 4 extending diagonals extend along the longitudinal axis of the fuse 1 or the recording area 4 Diagonal planes, in which the strip-shaped fusible links 3 extend. As, moreover, from the 1 to 3 results, are outside the diagonal planes no strip-shaped fuse element 3 ,

Through this exclusively diagonal arrangement of the fuse element 3 on the diagonals of the reception area 4 with a rectangular or square shape are the fusible links 3 further from the inner wall 6 spaced as in the case of a receiving area 4 with an oval or circular cross-sectional shape.

The 2a shows that each two fusible links 3 extend on one of the two diagonal planes, so that a total of four fusible links 3 in the recording area 4 are arranged, wherein a leg of the four-legged star-shaped cross-sectional shape through a fusible link 3 is formed.

2 B shows that four fuse links extend on one of the two diagonal planes, so that a total of eight fuse links 3 in the recording area 4 are arranged, wherein a leg of the four-legged star-shaped cross-sectional shape through two fusible links 3 is formed.

A comparison of the cross-sectional shape according to the invention with a round shape of the receiving area 4 is in 2a and 2 B played. There is the course of the inner wall 6 the in 1 shown fuse 1 dashed lines. Based on the illustrations according to 2a and 2 B is immediately apparent the advantage of the present invention. Due to the square or rectangular shape of the receiving area 4 in conjunction with an arrangement of fusible link 3 on the diagonals of the reception area 4 in cross-section is an increased space in the corner areas 5 to disposal. As a result, on the one hand, a greater spacing of the fusible conductor 3 to the inner wall 6 given so that in the area of the fusible conductor 3 possibly occurring arcs the inner wall 6 of the insulating body 2 do not reach or in the arc prevailing high temperatures are less strong on the insulator 2 impact.

The recording area 4 is filled with the arc extinguishing agent, not shown, which quickly causes an occurring arc in the event of overload to form an insulating sintered body. Opposite the dimensions of the fusible conductor 3 the formation of the sintered body is associated with a large increase in volume. During formation, the volume of the sintered body also increases in the direction of the inner wall 6 of the insulating body 2 to. As per the illustrations according to 2a and 2 B is illustrated, is the sintered body in the inventive design of the receiving area 4 with a rectangular or square-shaped cross-section compared to a round cross section, a larger clearance available. In the fuse according to the invention 1 So there is a greater spacing of the inner wall 6 of Isolierköpers 2 to the fusible link 3 and thus also to the hot sintered body. The pressure and especially the high temperature, which on the inner wall 6 of the insulating body 2 Act and ultimately crack or burst the insulator 2 can result in their effect on the insulator 2 significantly reduced.

The illustrations according to 2a and 2 B show in addition that in cross-section the inner wall 6 a cylindrical receiving area 4 a known fuse 1 with a round cross-sectional profile in comparison, preferably on the inscribed circle of the cross-sectional profile of the receiving area according to the invention 4 runs. The width of the fuse element arranged according to the invention 3 is therefore in particular smaller than the radius of the inscribed circle of the rectangular or. rectangular, or in the illustrated case square-like, cross-sectional profile of the receiving area 4 in the fuse according to the invention 1 , The distance of the fusible link 3 to the inner wall 6 is preferably more than 3 mm.

In the 3 also shown in cross-section, alternative embodiment of the fuse according to the invention 1 has a fundamentally comparable structure to that in 1 shown embodiment. However, in the example of the 3 the recording area 4 in its cross-sectional profile is not square-shaped, but rectangular.

The described advantages of the arrangement of the fuse element 3 on the diagonals of the rectangular cross-sectional shape of the receiving area 4 apply accordingly. The construction shown here of the fuse according to the invention 1 is used in special application situations, for example when comparatively wide fusible links 3 to accommodate a high rated current are required, but at the installation of the fuse 1 too little space is available, so that a flatter design of the fuse 1 is desired.

Basically, however, is the in 1 shown preferred design. In an inventive arrangement of four fuse elements 3 on the diagonal levels of the reception area 4 show the fusible links 3 each uniform angle to each other. As a result, there is between the fusible conductors 3 the largest possible or equally large free volume into which an emerging, hot sintered body can penetrate due to its thickness growth.

If desired or required, the available volume in the receiving area can be 4 further increase, if at least a page 7 of the cross-sectional profile of the receiving area 4 arcuate is formed. In this case, a circular arc section shape is preferred. However, another shape, for example parabolic or hyperbolic, may be provided.

At the in 1 shown embodiment, all sides 7 of the recording area 4 a bow portion-shaped shape, in particular the radius of curvature of all sides 7 is identical.

In comparison shows 3 in that with a rectangular receiving area 4 in particular the opposite sides each have the same radii of curvature. Here, the radius of curvature of a page corresponds 7 especially with the length of the page 7 , The example according to 3 illustrates that with increasing side length preferably also the radius of curvature increases, so that as a result the rectangular shape of the receiving area 4 results.

As further from the illustrations according to the 1 and 3 is apparent, is the corner area 5 between two adjacent pages 7 Preferably rounded and in particular has a smaller radius of curvature than the adjacent or adjacent sides 7 , As a result, the pickup area points 4 in its cross-sectional profile preferably the shape of a bulbous rectangle or square with rounded corners.

In conjunction with the preferred, also rectangular or rectangular cross-sectional shape of the insulator 2 on its outside leads the described shape of the receiving area 4 to an increased material thickness of the insulator 2 in the corner 5 that is, in the area in which the sintered body mainly expands when it is formed. Occurring forces and temperatures on the inner wall 6 of the insulating body 2 , especially in the corner area 5 , act, can thereby be absorbed to a greater extent and on the insulator 2 be derived or distributed.

A typical fusible link 3 is in 4 shown. The fusible conductor 3 consists of an electrically highly conductive material, in this case silver, and moreover has a solder whose melting point is lower than the melting point of the further material of the fusible conductor 3 is. As a result, a melting at a load current above the rated current in the fuse element 3 or a melting of the fusible conductor 3 reached above a defined current / time dependence.

The melting of the fusible conductor 3 in overload or short circuit occurs in particular at bottlenecks, which in the example shown as bottlenecks 8th are formed and in which the current flow through the fusible link 3 the highest current density is present. In the present example, the illustrated fusible conductor 3 a plurality of bottlenecks 8th on, in several bottleneck rows 9 are arranged, which the fusible link 3 into a plurality of continuous segments 10 divide.

In the event of overload, ie in the case of excessive current, the current density increases in one of the bottlenecks 8th to a degree that leads to such a strong heating of the material of the fusible conductor 3 causes this to melt and the conductive connection in the area of the bottlenecks 8th separates. As a result, the current density increases in the other bottlenecks 8th same bottleneck series 9 continue, so that there is a melting of other compounds at bottlenecks, that is more narrow bottlenecks 8th , comes. Is the last bottleneck 8th a bottleneck series 9 at a fusible link 3 separated, the current flows only over any further fusible link 3 the fuse 1 ,

In the case of four fusible links shown here 3 Thus, the current increases in the remaining, other fusible conductors 3 by about 1.3 times. This gradually leads to the bottlenecks of another remaining fusible link 3 to a melting until the relevant fusible link 3 also completely separated. Thereupon flows through the two remaining fusible links 3 now twice the current compared to the intact case of the fuse 1 with four conductive fuse conductors 3 ,

After the third fusible link 3 has been separated in the manner described above, now lies on the last remaining fusible link 3 four times the current, whereby also this fusible link 3 ultimately melts. This will make the conductive connection via the fusible link 3 through the fuse 1 separated.

The process described above occurs in the event of an overload, ie at a load current above the rated current, and takes place at different speeds depending on the extent of the overload. The short circuit case, however, is characterized by an extremely high and rapid increase in current, so that there is an almost simultaneous evaporation of all bottlenecks 8th a bottleneck series 9 or even to vaporize several bottleneck rows 9 comes.

However, as a rule, an arc is formed between the two separate sections of one or more fusible conductors 3 , Due to the free charge carriers in the hot plasma of the arc, the flow of current through the fuse 1 continue first. Due to the high temperatures in the arc, however, there is a sintering process of the fusible link 3 surrounding extinguishing agent, which in the present example is quartz sand. The resulting sintered body has a fulgurite-like or vitreous structure and is electrically insulating. Thus, ultimately, the circuit is finally separated by the formation of the sintered body and the fault current is turned off.

For external contacting are in the fuse according to the invention 1 in the present example end flange plates 11 provided, each having a contact neck 12 have, as in 5 is shown.

Inside are the fusible links 3 extending at least substantially over the entire length of the insulator 2 or the recording area 4 extend, end with the flange plates 11 conductively connected. In case of release of the fuse 1 may be in the range of electrically conductive connection between a fusible link 3 and a flange plate 11 extend the arc. In particular, in DC applications, such an arc can be comparatively durable and, in the limiting case, the flange plate 11 melt or strike through.

To the arcs described in the end of the fuse element 3 To limit, an electrically insulating material may be provided here. In this case, preferably silicone is used, which is available for a cost and on the other hand is easy to apply by its pasty consistency in said area. Therefore, insulating material beads are preferred 13 in the field of contacting the fusible link 3 with the flange plates 11 applied or applied, as in 5 is shown.

The star-shaped arrangement of the fuse element according to the invention 3 allows application of the electrically insulating material in the form of material beads 13 even in the already assembled state of the fuse from the fuse elements 3 and the one with the fusible conductors 3 connected flange plates 11 ,

6 shows that at least one other fusible conductor 14 in a space that results between the two diagonals, is provided. In the embodiment according to 6 it is envisaged that there are four fusible links 3 at least substantially along the two diagonals in the receiving area 4 extend. Between adjacent fuse links 3 is in the thus resulting gap at least one further fusible conductor 14 intended. 6 shows four fusible links 3 and four more fusible links 14 , In this case, the fusible link 3 as well as the other fusible links 14 at least substantially the same distance to the inner wall 6 and / or the housing corners or corner areas 5 and / or the pages 7 on. As a result, at least substantially the same distance to the wall of the receiving area results 4 , Further shows 6 in that the at least one further fusible conductor 14 a different width than the fusible link 3 can have. In 6 has the other fusible link 14 a smaller width than the fusible conductor 3 on. In further embodiments, it is provided that the further fusible conductor 14 about half the width of the fusible conductor 3 can have.

Further shows 6 in that the further fusible links 14 spaced from the center of the receiving area 4 , in particular the center of the star-shaped cross-sectional shape are arranged, wherein they are also spaced, in particular with a sufficiently large, distance from the fusible conductors 3 are arranged. In 6 have the other fusible link 14 a greater distance to the center of the receiving area 4 like the fusible link 3 on.

In further embodiments, it may be provided that the fusible conductor 3 has a width of about 20 mm and that the further fusible conductor 14 has a width of about 10 mm.

LIST OF REFERENCE NUMBERS

1

fuse

2

insulator

3

fuse element

4

reception area

5

corner

6

inner wall

7

page

8th

Engstellensteg

9

Engstellenreihe

10

segment

11

flange

12

Contact socket

13

bead of material

14

further fusible conductor

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102014212068 A1 [0002, 0006, 0007]
• DE 102012210292 A1 [0003]

Claims (15)

Fuse (1), preferably low-voltage fuse, preferably provided for use for a rated voltage range of greater than or equal to 900 V and / or for a rated current strength range of greater than or equal to 250 A, in particular for use in DC circuits, with an insulating body (2) and at least a strip-shaped fusible conductor (3), wherein the insulating body (2) has a receiving area (4) for receiving the fusible conductor (3), characterized in that the receiving area (4) has an at least substantially rectangular or rectangular shape in the cross section perpendicular to its longitudinal axis with diagonals extending between the corner regions (5) and that the fusible conductor (3) is arranged at least substantially in a diagonal plane of the receiving region (4). Fuse after Claim 1 , characterized in that a plurality of fusible conductors (3), in particular up to four or eight fusible conductors (3), at least substantially in at least one diagonal plane of the receiving region 4 is arranged. Fuse after Claim 1 or 2 , characterized in that the width of the fusible conductor (3) is less than or equal to the radius of the inner circle of the rectangular or rectangular cross-sectional profile of the receiving area (4) and that, preferably, the fusible links (3) are arranged exclusively in a diagonal plane. Fuse according to one of the preceding claims, characterized in that the receiving area (4) has a square or square cross-sectional shape. Fuse according to one of the preceding claims, characterized in that at least one side (7), preferably two in particular opposite sides (7), preferably all sides (7) of the rectangular receiving area (4) arcuate, in particular arcuate, are formed. Fuse according to one of the preceding claims, characterized in that opposite sides (7) of the receiving region (4) each have the same radii of curvature. Fuse according to one of the preceding claims, characterized in that the corner region (5) between two adjacent sides (7) is rounded and has a smaller radius of curvature than the adjacent sides (7). Fuse according to one of the preceding claims, characterized in that the insulating body (2) has an at least substantially rectangular or rectangular shape in the cross section perpendicular to its longitudinal axis on the outside. Fuse according to one of the preceding claims, characterized in that the fusible conductor (3) has a solder whose melting point is preferably lower than the melting point of the other materials of the fusible conductor (3). Fuse according to one of the preceding claims, characterized in that the fusible conductor (3) has at least one constriction, in particular a throat web (8), with a reduced line cross-section, preferably one or more constriction rows (9) each having a plurality of constriction webs (8), having. Fuse according to one of the preceding claims, characterized in that the receiving area (4) is filled with a the melting conductor (3) surrounding arc extinguishing agent, in particular sand. Fuse according to one of the preceding claims, characterized in that end-side flange plates (11) are provided for external contacting of the fuse (1). Fuse according to one of the preceding claims, characterized in that the fusible conductor (3) is conductively connected at the end to the flange plates (11). Fuse according to one of the preceding claims, characterized in that in the end region of the fusible conductor (3) is preferably an electrically insulating material, in particular silicone, is provided. Fuse according to one of the preceding claims, characterized in that at least one further fusible conductor (14) is provided, wherein the further fusible conductor (14) is arranged in a space between the corner regions (5) extending diagonal gap, in particular wherein the further fusible conductor (14) has a different, preferably smaller width than the fusible conductor (3).

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