Fuse and method for manufacturing the same

Abstract

Disclosed is a fuse, comprising at least one fuse insert (4), in which a reduced section (46A) is formed, which defines a plane (P4) transverse to the plane of the fuse insert. The fuse further comprises arc protectors (6) made of an elastic material and associated in pairs, and the arc protectors of the same pair are placed opposite each other on the corresponding main surfaces of the same fuse insert. Each arc protector comprises an inner surface (66) facing the fuse insert, a front surface (62) oriented towards the reduced section, and a rear surface (64) oriented away from the reduced section. At least one perforation (80) is formed near the reduced section of the fuse insert, and each perforation is at least partially closed by the inner surfaces (66) of the two arc protectors of the same pair, and a chamber is formed between the two arc protectors of the same pair in each perforation. The fuse insert according to the invention has a significantly shorter arc extinction time.

Description

Technical Field

[0001] The present invention relates to a fuse and an associated manufacturing method. Background Art

[0002] A fuse is an electrical component including two terminals and capable of interrupting the current flow between the two terminals in the case where an overcurrent exceeds a so-called fuse rating. The two terminals are fixed to an insulating body and are electrically connected to each other by at least one fuse link disposed in a chamber formed in the insulating body. Depending on the size of the fuse, one or more fuse links may be connected in parallel to the two terminals. When there are several fuse links, what is described for one fuse link also applies to the other fuse links.

[0003] The fuse link is made of a conductive material having a given resistance and a given melting temperature. In normal operation, current passes through the fuse link and the temperature of the fuse link remains below the melting temperature. In the case of an overcurrent, the temperature of the fuse link rises and the temperature at one or more points of the fuse link exceeds the melting temperature, at which the fuse link will at least partially melt and irreversibly cut off the current. Between the connections of the two poles, the fuse link includes at least one intermediate portion having a reduced surface section. Such an intermediate portion is called a "reduced section". Each reduced section provides a greater resistance compared to the other parts of the link. As the intensity of the current passing through the link increases, the temperature increase of each reduced section is greater than the temperature increase of the other parts of the link. In the case of an overcurrent, the link preferably melts at the reduced section.

[0004] When the reduced section melts, an arc is generated and the current continues to flow until the arc extinguishes. The arc, defined as a plasma state of matter, causes intense local heating, which facilitates the melting of the fuse link. Under thermal and electrical conditions, this change in the state of the material of the fuse in turn promotes the maintenance and prolongation of the arc.

[0005] To limit the propagation of the arc, it is known to place a silicone arc protection device on the fuse link.

[0006] For example, patent document US5,596,306 teaches to provide an arc protection device on either side of the reduced section. The arc protection device limits the arc but has no positive effect on the arc extinction time.

[0007] The present invention aims to more specifically solve these problems by proposing a fuse providing better performance. Summary of the Invention

[0008] To achieve the object of the present invention, the present invention relates to a fuse, comprising:

[0009] - At least one fuse insert formed in a sheet-like shape, having two opposite main surfaces extending along the longitudinal axis of the fuse insert, each fuse insert including a portion in which a reduced section is formed, the reduced section defining a plane transverse to the fuse insert,

[0010] - Two connection terminals, each terminal being connected to each fuse insert,

[0011] - Arc protectors made of an elastic material and associated in pairs, each in the same pair of arc protectors being placed opposite each other on the respective main surfaces of the same fuse insert, each arc protector including an inner surface facing the fuse insert, a front surface facing the reduced section, and a rear surface facing away from the reduced section,

[0012] According to the present invention, at least one perforation is formed near the reduced section of the fuse insert, each said perforation being at least partially closed by the inner surfaces of two arc protectors in the same pair, while each perforation forms a chamber between the two arc protectors in the same pair.

[0013] The fuse insert of the present invention including perforations at least partially covered by arc protectors has a significantly shorter arc extinction time compared to a fuse insert without perforations. The perforations facilitate the progression of the arc, and the arc extinguishes faster than an arc without an arc protector. Therefore, for a fuse of a given rating (i.e., suitable for a given voltage and / or power), a more compact and thus more economical fuse can be designed.

[0014] According to an advantageous but non-compulsory aspect of the present invention, such a fuse may incorporate one or more of the following features used in an independent or any technically feasible combination:

[0015] - Perforations are made on each side of the reduced section of the fuse insert, and while the fuse includes a first pair of arc protectors in addition to a second pair of arc protectors, the first pair and the second pair of arc protectors respectively at least partially enclose the perforations formed on each side of the reduced section;

[0016] - The perforations have an elongated shape and are arranged along their length parallel to the longitudinal direction of the fuse insert;

[0017] - The perforations extend parallel to the longitudinal direction of the fuse insert beyond the rear surface of the arc protector to form a rear vent;

[0018] - The length of the rear vent is between 0.1 mm and 10 mm, preferably between 0.5 mm and 8 mm, more preferably between 1 mm and 5 mm;

[0019] - The perforations extend parallel to the longitudinal direction of the fuse insert and beyond the front surface of the arc protector to form a front vent;

[0020] - The length of the front vent is between 0.1 mm and 5 mm, preferably between 1 mm and 3 mm;

[0021] - The length between the front surface and the rear surface of each arc protector is between 5 mm and 30 mm;

[0022] - The distance between the front surface of the arc protector and the boundary line of the relatively placed reduced section is between 0.5 mm and 20 mm, preferably between 1 mm and 15 mm, more preferably between 2 mm and 12 mm;

[0023] - The arc protector is made of a material having a hardness measured in Shore A hardness between 20 and 90, preferably between 40 and 70;

[0024] - The arc protector is made of an elastomeric material, preferably made of silicone;

[0025] - For at least the first pair of arc protectors, the arc protectors are made of a preformed material, and an adhesive layer is inserted between the fuse insert and the inner surface of each of the pair of arc protectors, the inner surface facing one of the main surfaces of the fuse insert, so as to fix each arc protector to the fuse insert, and

[0026] - The fuse includes a frame, the frame is received in a chamber of the fuse body, and the movement of the fuse insert relative to the body is restricted by means of spacers and / or gaskets, and

[0027] The present invention also relates to a method of manufacturing a fuse as described above, the fuse including at least one fuse insert having a reduced section that defines a transverse plane transverse to the fuse insert. The method includes the following steps:

[0028] - Providing at least one perforation on one side of the transverse plane of the fuse insert,

[0029] - Assembling two arc protectors of the first pair on the corresponding main surfaces of the fuse insert near the reduced section so that each perforation is at least partially closed by the arc protector, and the distance between the front surface of each arc protector and the boundary line of the relatively placed reduced section is between 1 mm and 15 mm.

[0030] Advantageously, the method comprises the steps of: prior to the assembly step, manufacturing a first pair of two arc protectors made of a crosslinked elastomeric material and having a flat inner surface. In the assembly step, an adhesive layer is inserted between the inner surface of each arc protector and the respective main surfaces of the fuse blades so as to bond the two arc protectors of the first pair to the fuse blades. Description of the Drawings

[0031] With reference to the accompanying drawings, the present invention will be better understood from the following description of several embodiments of a fuse according to its principles, given by way of example only, and other advantages of the present invention will become more apparent, in which:

[0032] - Figure 1 Is a perspective view of a fuse according to a first embodiment of the present invention, the fuse comprising a plurality of fuse blades and arc protectors, with some components schematically shown for ease of reading;

[0033] - Figure 2 Is Figure 1 Of the fuse in Figure 1 View in the direction of arrow II in

[0034] - Figure 3 Is Figure 1 Of the fuse blades and arc protectors in Figure 1 Larger-scale schematic perspective view in the direction of arrow III in

[0035] Figure 4 Illustrations a) and b) in Figure 1 Schematically show two views of the same fuse blades and arc protectors of

[0036] - Figure 5 Is similar to Figure 4 Of the drawing, showing the same fuse blades and arc protectors according to another embodiment of the present invention;

[0037] - Figure 6 Is similar to Figure 4 Of the drawing, showing the same fuse blades and arc protectors according to another embodiment of the present invention;

[0038] - Figure 7 Is a graph showing the variation of the current flowing through the fuse blades according to the prior art or according to an embodiment of the present invention;

[0039] - Figure 8 Is a block diagram showing the steps of a method for manufacturing fuse blades and arc protectors according to an embodiment of the present invention;

[0040] - Figure 9 is similar to Figure 3 the accompanying drawings, showing a fuse blade and an arc protector according to another embodiment of the present invention; and

[0041] - Figure 10 the illustrations a) and b) in Figure 9 schematically represent two views of the same fuse blade and arc protector of DETAILED DESCRIPTION

[0042] Figure 1 The fuse 2 is shown in

[0043] The fuse 2 includes a body 20 (shown in dashed lines) and two connection terminals 22. The body 20 is made of an insulating material, such as ceramic. The body 20 generally has an elongated cylindrical shape defining a longitudinal axis A2 of the fuse 2. In the example shown, the body 20 has a parallelepiped shape, that is, the body 20 is a column with a rectangular cross-section. In a non-limiting variant, the body 20 has an elliptical or circular cross-section. The transverse direction is defined as the direction orthogonal to the longitudinal axis A2. The transverse plane of the fuse 2 is thus a plane orthogonal to the longitudinal axis A2.

[0044] In the example shown, the terminals 22 are arranged on two opposite corresponding surfaces of the body 20, and these two surfaces are orthogonal to the longitudinal axis A2. Each terminal 22 has a columnar shape with an elliptical cross-section and the shape of a generator parallel to the longitudinal axis A2. An elliptical hole 24 passes through each terminal 22. Each terminal 22 includes a plate 26, and the plate 26 is intended to assemble the fuse 2 to a fuse base (not shown).

[0045] The body 20 of the fuse 2 includes a chamber V20, and a fuse blade 4 is accommodated in the chamber V20. Each fuse blade 4 includes two opposite attachment ends 40, and each attachment end 40 is connected to one of the terminals 22. The fuse blade 4 is thus electrically connected in parallel with the terminal 22. In other words, each terminal 22 is connected to one of the corresponding attachment ends 40 of each fuse blade 4.

[0046] The number of the fuse blades 4 is four here, and this number varies according to the size of the fuse 2, particularly depending on the voltage and current amperage that the fuse 2 is designed for. When the fuse 2 includes a plurality of fuse blades 4, the fuse blades 4 advantageously have the same structure and operate in the same manner. The fuse blades 4 of the fuse 2 are preferably exactly the same. The description of one fuse blade 4 can be applied to other fuse blades 4.

[0047] The fuse insert 4 is an element made of a conductive material, which has a resistance and a melting temperature. The material of the fuse insert 4 is preferably metallic (e.g., silver, doped Ag). Each fuse insert 4 has an elongated rectangular shape, with the long side of the rectangle arranged parallel to the longitudinal axis A2. Each fuse insert 4 has a constant width, which is measured transversely to the longitudinal axis A2.

[0048] Each fuse insert 4 herein has a shape symmetric with respect to the transverse plane P4 and is formed as a sheet, which has two opposite main surfaces that extend along the longitudinal axis A2 and include flat portions separated by a transverse folding portion 42. In the example shown, the flat portions of the same fuse insert 4 are located in the same mid-plane, and the mid-planes of each fuse insert 4 are parallel to each other and define the main axis A4. The main axis A4 is an axis transverse to the longitudinal axis A2. As a variant, the flat portions of the same fuse insert 4 are not entirely located in the same mid-plane.

[0049] In some flat portions of each fuse insert 4, multiple rows of holes 44 are formed, and the direction of each row of holes 44 is transverse to the longitudinal axis A2 and defines a constricted section 46. In other words, each fuse insert 4 includes an intermediate portion between two attachment ends 40, and the constricted section 46 is provided in this intermediate portion.

[0050] The resistance of each fuse insert 4 at the location of each constricted section 46 is greater than the resistance at locations outside each constricted section 46. Therefore, when current flows between the terminals 22, the fuse insert 4 will be locally heated at the constricted section 46. In the case of overcurrent, the melting of the material of the fuse insert 4 preferably occurs at the constricted section 46.

[0051] In the example shown, each fuse insert 4 has several types of constricted sections 46. Depending on the constricted section 46 considered, the holes 44 have different diameters, for example. Therefore, when overcurrent occurs, some constricted sections 46 may melt faster than other constricted sections. When the fuse insert 4 includes a single type of constricted section 46, its response curve "cut-off time / cut-off current" has a given shape. By combining different types of constricted sections 46, a response curve is obtained, which is the superposition of each response curve corresponding to each constricted section. This aspect will not be further elaborated in this specification.

[0052] In the example shown, the fuse 2 further includes a frame 48, which is received in a chamber V20 of the body 20. The frame 48 is not essential for the implementation of the invention described in this specification, but contributes to its implementation. The frame 48 is particularly used to assemble the body 20 to the rest of the fuse 2 and hold the fuse tabs 4, for example to protect them during the manufacture of the fuse 2. The fuse tabs 4 are actually very thin and elastic, and the thickness of the fuse tabs 4 can be on the order of 0.1 mm or less.

[0053] The frame 48 is made of an insulating material, such as a synthetic material, which is preferably rigid and optionally reinforced with inorganic fibers such as glass fibers. As a non-limiting example, the frame 48 can be made of polyimide (also denoted as PI), polyetheretherketone (also denoted as PEEK), polytetrafluoroethylene (also denoted as PTFE), polyamide (also denoted as PA), silicone or polyphenylsulfone (also denoted as PPSU).

[0054] In the example shown, the frame 48 includes two side panels 50, which are opposite to each other and connected to each other by spacers 52. The structure of the frame 48 is non-limiting.

[0055] Each side panel 50 includes a notch 54 for holding the fuse tab 4 on a surface facing the other side panel 50.

[0056] In Figure 2 the example shown, the spacers 52 are shown in cross-section and the side panels 50 are not shown. The spacers 52 are grouped together into two stacks 56 here, each stack 56 having five spacers 52, and each stack 56 is arranged near the attachment end 40 of the fuse tab 4 here. The fuse tab 4 is thus held between two adjacent spacers 52 by pressing, while two spacers 52 located at the ends of each stack 56 are supported on the body 20 (inside the chamber V20). When the body 20 is assembled to the rest of the fuse 2, the spacers 52 limit the amplitude of movement of the fuse tab 4 relative to the rest of the fuse 2.

[0057] In addition to the fuse tabs 4 and the frame 48 received in the chamber V20 of the body 20, the chamber V20 is generally filled with a powder, the function of which is to absorb a part of the energy of the arc occurring in the case of overcurrent, contribute to the faster extinction of the arc and the faster interruption of the current. Such a powder (not shown in the drawings) preferably takes the form of micron-sized particles and is, for example, silica sand.

[0058] In the example shown, one of the constricted sections 46 of each fuse blade 4 (designated 46A) is arranged in a transverse plane that coincides with the transverse plane P4. In the following, the constricted section 46A is mainly considered, since what is known to be valid for the constricted section 46A can generally be applied to the other constricted sections 46 as well.

[0059] The arc protectors 6 (visibly in cross-section in Figure 2 and shown in perspective in greater proportion in Figure 3 are arranged in the vicinity of each constricted section 46A. In particular, for each constricted section 46A, four arc protectors 6 are arranged, which are symmetric with respect to the transverse plane P4 on the one hand and symmetric with respect to the fuse blade 4 on the other hand. Two arc protectors 6 located on the same side of the transverse plane P4 thus form a pair 60 of arc protectors 6, and the arc protectors 6 of the same pair 60 are positioned opposite each other on the respective main surfaces of the same fuse blade 4.

[0060] In the example shown, two pairs 60 of arc protectors 6 are separated from each other by a single constricted section 46A. In a variant not shown, two pairs 60 of arc protectors 6 are separated from each other by a number of constricted sections 46 or 46A.

[0061] The arc protectors 6 have a similar shape and operate in the same way. In particular, the arc protectors 6 of the same pair 60 are preferably identical. In the remainder of the description, it is considered that the four arc protectors 6 located in the vicinity of the constricted section 46A are identical.

[0062] The arc protectors 6 (also referred to as "arc suppressors") are made of an elastic material, i.e., a material that is capable of deforming under the action of mechanical stress and of reverting to its initial shape when that mechanical stress is interrupted.

[0063] In the example shown, the arc protectors 6 are made of an elastomeric material. The elastomeric material of the arc protectors 6 is, for example, polysiloxane, also known as silicone resin.

[0064] Advantageously, the arc protectors 6 are made of a prefabricated material, i.e., a material that has already been crosslinked. The crosslinked silicone resin material is a solid material with a defined shape and can be easily processed, in particular can be easily cut and / or machined to strict dimensional tolerances, while the non-crosslinked silicone resin material is usually in the form of a dough and has no defined shape.

[0065] The fuse 2 further includes a spacer 58 which is connected to the fuse blade 4 or the arc protector 6 so as to be fixed relative to the fuse blade 4, especially during the assembly or operation of the fuse 2. Thus, during the assembly of the fuse 2, the forces generated due to the operation are distributed among all the fuse blades 4, which reduces the risk of damaging the fuse blades 4.

[0066] The spacer 58 is also capable of fixing the fuse blade 4 relative to the frame 48 (when present) and / or relative to the body 20 when the fuse 2 is fully assembled. Optionally, when the frame 48 is present, some spacers 58 cooperate with the notches 54 or with other structures of other shapes or machined formed in the frame 48 which are not shown, to limit the movement of the fuse blade 4 relative to the frame 48. More generally, the frame 48 limits the movement of the fuse blade 4 through the spacers 52 and / or the spacers 58. Thus, during the assembly of the fuse 2, the fuse blade 4 is protected by the frame 48. The assembly operation can be carried out faster, reducing the possibility of malfunctions, which is economically advantageous.

[0067] In Figure 2 the example of, each spacer 58 has the shape of a parallelepiped. Advantageously, the spacer 58 is made of the same material as the material of the arc protector 6, for example made of a crosslinked elastomeric material such as silicone resin. In Figure 2 it, the spacer 58 and the arc protector 6 are schematically shown. In particular, there is no limitation on the ratio between the sizes of the arc protector 6 and the spacer 58.

[0068] In the example shown, the reduced section 46A of the fuse blade 4 is aligned on the transverse plane P4, and the arc protector 6 is arranged on either side of the transverse plane P4. Some spacers 58 located near the reduced section 46A are inserted between two arc protectors 6 which are located on the same side of the transverse plane P4 and respectively belong to two adjacent fuse blades 4.

[0069] Advantageously, the spacer 58 is fixed to the fuse blade 4 or the arc protector 6 by adhesion (i.e., in a manner similar to that subsequently described in this specification), where the arc protector 6 is attached to the fuse blade 4.

[0070] As a variant, when the arc protector 6 is in contact with the spacer 58, the spacer 58 is integral with the arc protector 6. This arc protector 6 on the one hand helps to extinguish the arc, and on the other hand, helps to hold the fuse blade 4.

[0071] When the fuse 2 is fully assembled, the spacer 58 is slightly compressed in the direction of the main axis A4. In particular, the arc protector 6 is slightly compressed in the direction of the main axis A4 through the spacer 58.

[0072] When there is a frame 48, some gaskets 58 cooperate with the frame 48 to compress the arc protector 6 in the direction of the main axis A4.

[0073] A sub-assembly is now described that includes a fuse blade 4 having a reduced section 46A and two pairs 60 of arc protectors 6 located near the reduced section 46A (in particular with reference to Figure 3 ).

[0074] Each arc protector 6 here has an elongated parallelepiped shape and is arranged such that its length is parallel to the reduced section 46A. The length of each arc protector 6 here is equal to the width of the fuse blade 4. In a variant not shown, the length of each arc protector 6 is greater than the width of the fuse blade 4. Each arc protector 6 has a front surface 62 that faces the reduced section 46A (the arc protector 6 is located near the reduced section 46A), and a rear surface 64 that is opposite to the front surface 62. In other words, the rear surface 64 faces away from the reduced section 46A. The length L6 is defined as the length between the front surface 62 and the rear surface 64.

[0075] Each arc protector 6 has an inner surface 66 facing the main surface of the fuse blade 4 and an outer surface 68 that is oriented opposite to the inner surface 66. The thickness L7 of the arc protector 6 is defined as the distance between the inner surface 66 and the outer surface 68.

[0076] Two boundary lines 70 of the reduced section 46A are defined as two lines parallel to the transverse plane, located on either side of the plane P4 and containing the reduced section 46A. The two boundary lines 70 are each tangent to at least one hole 44 of the reduced section 46A. Thus, each boundary line 70 is located between the reduced section 46A and the front surface 62 of the adjacent arc protector 6. In Figure 3 the example shown, the holes 44 of the reduced section 46A are all aligned and have the same diameter, so the boundary lines 70 are tangent to all the holes 44 of the reduced section 46A.

[0077] For each arc protector 6, a distance L8 is defined between the arc protector 6 and the opposite reduced section 46A. The distance L8 is the distance, measured parallel to the longitudinal axis A2, between the front surface 62 of the arc protector 6 and the boundary line 70 closest to the opposite reduced section 46A.

[0078] Advantageously, each arc protector 6 is assembled to the fuse blade 4 by adhesion. To this end, for each arc protector 6, an adhesive layer 72 is inserted between the inner surface 66 and the surface of the oppositely placed fuse blade 4 so as to fix the arc protector 6 to the fuse blade 4. In other words, each arc protector 6 is adhered to the fuse blade 4. To ensure that each arc protector 6 is properly fixed to the fuse blade 4, each inner surface 66 is preferably flat.

[0079] When two arc protectors 6 of the same pair 60 are fixed to the fuse blade 4, the inner surfaces 66 of the arc protectors 6 of the same pair 60 overlap each other.

[0080] Each adhesive layer 72 is preferably a thin layer, i.e., having a thickness between 10 μm and 0.5 mm, preferably less than 0.1 mm. Each adhesive layer 72 is preferably uniform, i.e., the adhesive layer 72 has a constant thickness over the entire inner surface 66.

[0081] According to an example, the adhesive layer 72 is directly applied to the fuse blade 4, then the arc protector 6 is positioned on the fuse blade 4, and then set stationary to allow the adhesive time to harden.

[0082] Preferably, the inner surface 66 of the arc protector 6 is pre-adhered, i.e., the adhesive layer 72 is directly applied to the inner surface 66 of the arc protector 6. Then the pre-adhered arc protector 6 is positioned on the fuse blade 4 and then set stationary (e.g., by means such as a fixing clip) to allow the adhesive time to harden. The fixing clip is not shown. Depending on the composition of the adhesive layer 72, the attachment of the arc protector 6 to the surface of the fuse blade 4 can be instantaneous. "Instantaneous" means that the hardening of the adhesive layer 72 only takes a few seconds, e.g., less than 10 seconds, which is very short compared to the crosslinking time of an uncrosslinked silicone resin material.

[0083] The adhesive layer 72 is applied, for example, by spraying. As a variant, the adhesive layer 72 can be a so-called "double-sided" adhesive, i.e., the adhesive layer includes a substrate such as a sheet made of paper or an insulating polymer, and both sides of the substrate are coated with a corresponding adhesive film. The use of the double-sided adhesive allows for easy assembly of the fuse 2.

[0084] During use, the fuse 2 heats up due to the current flowing through it, and the temperature of the fuse 2 may be higher than 100 °C, e.g., between 150 °C and 200 °C, and last for months or even years. The adhesive selected for fixing the arc protector 6 to the fuse blade 4 needs to withstand these operating conditions. On the other hand, when the fuse 2 blows and an arc appears, the adhesive may be exposed to the arc. The adhesive is selected so as not to cause an exothermic reaction when subjected to the arc.

[0085] As a non-limiting example, the adhesive is an inorganic adhesive (such as a silicone adhesive), or an organic adhesive (such as a cyanoacrylate adhesive, an epoxy adhesive, or a vinyl or acrylic, or aliphatic, or polyurethane, or neoprene adhesive, etc.). Depending on the type of adhesive used, surface activation may be required, for example, on the inner surface 66 of the arc protector 6.

[0086] In Figure 4 , the fuse 2 according to the present invention includes perforations 80 formed on each side of the reduced section 46A on the fuse tab 4, in other words, on either side of the transverse plane P4. In the first embodiment, the perforations 80 are covered by the arc protector 6, that is, as long as the fuse 2 has not melted, the perforations 80 are completely sealed by the inner surface 66 of the arc protector 6 in the direction of the main axis A4. However, the inner surfaces 66 of each pair 60 of arc protectors 6 do not contact each other so as not to block the corresponding perforations 80 in the direction of the longitudinal axis A2. Each perforation 80 thus forms a chamber between the two arc protectors 6 of the same pair 60.

[0087] In Figure 4 Illustrations a) and b) show the same fuse tab 4. Where illustration b) shows a portion of the fuse tab 4 of illustration a) along the section 4b on illustration a).

[0088] The working principle of the fuse tab 4 is now schematically described. The fuse tab 4 includes an arc protector 6 disposed near the reduced section 46A, and the arc protector 6 encloses the perforations 80. When the fuse tab 4 connected to the circuit is traversed by an excessive current, the reduced section 46A melts and an arc appears at the reduced section 46A. As long as the arc exists, the current continues to flow through the fuse tab 4, the material of the fuse tab 4 continues to melt, and the arc continues to spread from the reduced section 46A. As the arc length increases, the arc voltage increases. Finally, when the arc voltage reaches a value greater than the circuit voltage, the arc extinguishes and no current flows through the fuse tab 4 anymore. The time between the moment the arc appears and the moment the arc extinguishes defines the cut-off time of the fuse 2.

[0089] In the context of the present invention, two arc protectors 6 in a pair 60 form a restricted area therebetween that guides the ionic products generated by an arc as the arc travels. Thus, the travel of the arc is guided in a preferred direction parallel to the longitudinal axis A2 and simultaneously away from the constricted section 46A. The travel of the arc so guided is faster than would be the case in the absence of arc protectors 6, as is the case in the prior art. As the arc grows faster, the arc voltage will also rise faster, and arc extinction will be achieved more quickly. Due to the arc protectors 6, the cut-off time of the fuse blade 4 is shortened. In other words, the fuse 2 including the arc protectors 6 has a faster cut-off time on either side of the constricted section 46A.

[0090] Once the arc reaches the front surface 62 of the arc protector 6, the perforations 80 reduce the amount of material to be melted during the travel of the arc. Thus, as Figure 7 shown, the travel of the arc is faster than would be the case without the perforations 80. In the direction parallel to the longitudinal axis A2 of the fuse 2, the perforations 80 are not blocked by the arc protector 6 so as not to impede the travel of the arc.

[0091] As long as the arc has not reached the arc protector 6, the arc protector 6 does not significantly affect the travel speed of the arc, i.e., the travel speed of the arc is similar to that without the arc protector. If the arc protector 6 is too far from the constricted section 46A, the action of the arc protector 6 is unnecessarily delayed.

[0092] Conversely, if the arc protector 6 is too close to the constricted section 46A, when an arc occurs, the heat generated by the constricted section is too great, and there is a risk of damaging the material of the arc protector 6, for example by carbonization. Also, in normal operation, the constricted section 46A gets hotter than other parts of the fuse blade 4. If the arc protector 6 is too close to the constricted section 46A, the arc protector 6 may age faster, especially harden, which is undesirable for reasons explained later in this specification. Therefore, the distance L8 between the arc protector 6 and the boundary line 70 of the constricted section is between 1 mm and 15 mm, preferably between 3 mm and 10 mm, more preferably between 4 mm and 8 mm. A distance L8 equal to 6 mm gives good results.

[0093] For the sealing effect of the arc protector 6 to be significant and to prevent the arc from being able to bypass the arc protector 6, the arc protector 6 must in particular have a sufficient thickness L7. Thus, the thickness L7 of each arc protector 6 is greater than 0.2 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm. A thickness L7 equal to 2 mm gives good results. The thickness L7 is not limited, except for example for practical spatial reasons (especially during the assembly of the fuse 2). Thus, the thickness L7 is less than 20 mm, preferably less than 10 mm, more preferably less than 5 mm.

[0094] For the sealing effect of the arc protector 6 to be even more significant, the arc must also be guided over a sufficient length so that the arc voltage reaches the circuit voltage before the arc appears on the side of the rear surface 64 of the arc protector 6. If the length L6 of the arc protector 6 is too short, the arc will appear on the side of the rear surface 64 of the arc protector 6 and then continue to travel at a speed similar to that in the case without an arc protector. Thus, each arc protector 6 has a length L6 greater than 5 mm, preferably greater than 7 mm. The length L6 is not limited, except for example for practical spatial reasons. Thus, the length L6 is less than 30 mm, preferably less than 25 mm, more preferably less than 20 mm.

[0095] The hardness of the elastic material of the arc protector 6 has no significant effect on shortening the cut-off time of the fuse 2. The hardness of the elastic material of the arc protector 6 is evaluated on a Shore-A scale, with the Shore-A hardness ranging from 0, which represents a very soft material, to 100, which represents a very hard material. The sealing effect of a material that is too soft with a Shore-A hardness of less than 20 is insufficient. A hardness greater than 40 is preferred.

[0096] Conversely, an arc protector 6 made of a material that is too hard also does not provide good performance. Thus, the material of the arc protector 6 is selected to have a Shore-A hardness of less than 90. On the other hand, under the operating conditions of the fuse 2, the temperature that the arc protector 6 is subjected to may exceed 100 °C or 150 °C, and the elastomer will harden with aging. Thus, the material of the arc protector 6 is selected such that its Shore-A hardness remains less than 90 even after aging. Thus, preferably, the Shore-A hardness of the new material of the arc protector 6 is selected to be less than 70.

[0097] Thus, the arc protector 6 is made of a material having a hardness measured on the Shore-A scale between 20 and 90, preferably between 40 and 70.

[0098] Surprisingly, the mechanical compression state of the arc protector 6 has a positive effect on reducing the opening time of the fuse 2. Advantageously, when the fuse 2 is assembled, the arc protector 6 is slightly compressed in a direction parallel to the main axis A4 (i.e., a direction orthogonal to the main surface of the fuse blade 4 at the location where these arc protectors 6 are located). When the fuse 2 is assembled, each arc protector 6 is compressed and the thickness L7 is less than 99% of the thickness L7 of the same arc protector 6 when the arc protector is not subjected to any external stress, preferably less than 98%, more preferably less than 95%.

[0099] The compression of the same pair of arc protectors 6 is achieved by a specific device such as a compression clip and / or by the frame 48 when present (e.g., by the spacer 58).

[0100] The compression clips are not shown. These fixing clips are also advantageously used as compression clips when fixing the arc protector 6 during assembly and giving the adhesive time to harden, and remain on the arc protector 6 once the adhesive layer 72 has hardened.

[0101] Advantageously, each perforation 80 has an elongated shape and is arranged such that its length is parallel to the longitudinal axis A2 of the fuse 2, in other words, parallel to the longitudinal direction of the fuse blade 4. Schematically, the elongated perforation 80 provides a channel parallel to the longitudinal axis A2 and facilitating the travel of the arc. In a first embodiment of the invention, each perforation 80 has a length measured parallel to the longitudinal axis A2 of the fuse 2, which length is substantially equal to the length L6 of the arc protector 6 enclosing the perforation 80.

[0102] The perforations 80 formed on one side of the transverse plane P4 are preferably symmetric with the perforations 80 formed on the other side of the transverse plane P4. The perforations 80 located on the same side of the transverse plane P4 form a group of perforations 80. In the first embodiment, the perforations 80 of the same group are thus completely enclosed by the inner surfaces 66 of the two arc protectors 6 of the same pair 60.

[0103] In the example shown, each group of perforations 80 includes three perforations 80, and this number is not limiting. As a variant, each group of perforations 80 includes a single perforation 80, or two, or four or more.

[0104] The perforations 80 of the same group are preferably arranged in a row, i.e., aligned with each other in a direction transverse to the fuse blade 4, in other words, in a direction orthogonal to the longitudinal axis A2.

[0105] In Figure 4In the example shown in illustration a), the perforations 80 have a rectangular cross-section. In a non-limiting variant, the perforations 80 have an oval or elliptical shape, or a rhomboid shape, or more generally a rectangular shape. The shape of the perforations 80 depends in particular on the manufacturing method of the perforations 80, which are made, without limitation, by stamping, laser cutting or by electro-erosion. Each of the perforations 80 in the same group preferably has the same shape.

[0106] For each group of perforations 80, the greater the number of perforations 80, the greater the width (measured parallel to the transverse direction of the fuse insert 4), and the greater the resistance (measured parallel to the longitudinal axis A2 of the fuse 2), the longer the passage of this group of perforations 80. However, unlike the constriction sections 46 or 46A, the purpose of the perforations 80 is not to promote the initiation of an arc in the case of an overcurrent, but to provide a passage that is favorable for the progression of the arc in the case where the arc reaches the arc protector 6.

[0107] For each fuse insert 4, the surface section of a group of perforations 80 measured along the longitudinal axis of this fuse insert 4 is more than five times higher, preferably more than ten times higher, than the smallest surface section in the constriction section 46 or 46A provided on this fuse insert 4.

[0108] The perforations 80 of the same group are preferably evenly spaced in the transverse direction of the fuse insert 4 in order to avoid locally weakening the material of the fuse insert 4 or to avoid generating hot spots when the current flows in the fuse insert 4.

[0109] In Figure 5 and Figure 6 are shown the fuse insert 4 and the arc protector 6 according to the second and third embodiments of the present invention respectively. While the fuse insert 4 and the arc protector 6 according to the fourth embodiment of the present invention are shown in Figure 9 and Figure 10 Elements similar to those of the first embodiment have the same reference numerals and operate in the same way. In the following, the differences between each embodiment and one or more of the previous embodiments are mainly described.

[0110] Figure 5 One of the main differences between the second embodiment shown in

[0111] Each perforation 80 extends beyond the rear surface 64 of the adjacent arc protector 6 parallel to the longitudinal axis A2 of the fuse 2. Each perforation 80 thus includes a rear portion located on the side opposite to the reduced section 46A, which projects from the rear surface 64 and forms a rear vent 82 through which the perforation 80 is open.

[0112] When an arc travels between the arc protectors 6 of the same pair 60, the rear vent 82 can discharge the products generated by the arc more quickly, especially molten metal or other ionized products. The rapid elimination of these products disrupts the stability of the arc, thereby shortening the time required to achieve complete interruption of the current.

[0113] For each perforation 80, the length L82 is defined as: measured parallel to the longitudinal axis A2 of the fuse 2, the length between the end of the perforation 80 furthest from the reduced section 46A and the rear surface 64 of the adjacent arc protector 6. The length L82 thus represents the length of the rear vent 82. The length L82 is between 0.1 mm and 10 mm, preferably between 0.5 and 8 mm, and more preferably between 1 mm and 5 mm.

[0114] Thus, in the second embodiment, the same group of perforations 80 is partially enclosed by the inner surfaces 66 of the two arc protectors 6 of the same pair 60.

[0115] Figure 6 One of the main differences between the third embodiment shown and the second embodiment is that the perforations 80 project from the arc protector 6 on the side facing the reduced section 46A. In Figure 6 Illustrations a) and b) of the same fuse insert 4 are shown, and illustration b) represents the part of the fuse insert 4 in illustration a) along the section 6b in illustration a).

[0116] Each perforation 80 extends beyond the front surface 62 of the arc protector 6 parallel to the longitudinal axis A2 of the fuse 2. Each perforation 80 thus includes a front portion located on the side of the reduced section 46A, which projects from the front surface and forms a front vent 84 through which the perforation 80 is open. Thus, in the third embodiment, the perforations 80 in the same row are partially enclosed by the inner surfaces 66 of the two arc protectors 6 of the same pair 60.

[0117] When an arc travels towards the arc protectors 6 of the same pair 60, the front vent 84 allows a part of the molten metal and / or other ionized products generated by the arc to be discharged near the reduced section 46A, and the chamber V20 is filled with sand. These ionized products thus no longer promote the maintenance of the arc.

[0118] For each perforation 80, the length L84 is defined as: measured parallel to the longitudinal axis A2 of the fuse 2, the length between the end of the perforation 80 closest to the constriction section 46A and the front surface 62 of the adjacent arc protector 6. The length L84 thus represents the length of one of the front vents 84. The length L84 is between 0.1 mm and 5 mm, preferably between 1 and 3 mm.

[0119] Figure 7 Figure 700 shows the variation of the current flowing through the fuse insert 4, which includes a constriction section 46A for different fuse inserts 4 with different characteristics. The performance of the fuse 2 is particularly evaluated by the cut-off time, which is the time required from the start of melting of the constriction section 46A to the elimination of the current.

[0120] Curve 99 shows the variation of the current in the case where the fuse insert 4 does not include an arc protector near the constriction section 46A. An arc appears at time t0. The current is zero at time t 99 is zero. The cut-off time is equal to t 99 - t0.

[0121] Curve 100 shows the variation of the current in the case where the fuse insert 4 includes an arc protector 6 but does not have the perforation 80 as described above. Two pairs of arc protectors 6 are provided on both sides of the constriction section 46A. At time t 100 the current is zero. The cut-off time of the fuse insert 4 including the arc protector 6 is equal to t 100 - t0, which is approximately 40% less than the cut-off time of the fuse insert 4 without an arc protector.

[0122] Curve 200 shows the variation of the current in the case where the fuse insert 4 includes an arc protector 6 according to the first embodiment of the present invention as described above (i.e., a perforation 80 is formed in the fuse insert 4 between the arc protectors 6 of the same pair 60). The current is zero at time t 200 The cut-off time of the fuse insert 4 including the arc protector 6 with a perforation is equal to t 200 - t0, which is approximately 45% less than the cut-off time of the fuse insert 4 without an arc protector.

[0123] Curve 300 shows the variation of the current in the case where the fuse insert 4 includes an arc protector 6 according to the second embodiment of the present invention as described above (i.e., the perforation 80 extends from the arc protector 6 on the side opposite to the constriction section 46A). The current is zero at time t 300 The cut-off time of the fuse insert 4 including the arc protector 6 with a perforation and a rear vent 82 is equal to t 300-t0, which is approximately 50% less than the cut-off time of the fuse blade 4 without the arc protector.

[0124] Curve 400 shows the change in current when the fuse blade 4 includes the arc protector 6 according to the third embodiment of the present invention described above (i.e., the perforations 80 extend from both sides of the reduced section 46A and from the side opposite to the reduced section 46A on the arc protector 6). At time t 400 the current is zero. The cut-off time of the fuse blade 4 including the arc protector 6 having the perforations and the front vent 84 and the rear vent 82 is equal to t 400 -t0, which is approximately 60% less than the cut-off time of the fuse blade 4 without the arc protector.

[0125] Figure 7 Shows an aspect of the performance improvement of the fuse 2 according to the present invention in terms of reducing the cut-off time compared to the prior art fuse without the arc protector 6. The fuses 2 according to the first, second and third embodiments of the present invention (where the perforations 80 located on the same side of the reduced section 46A are at least partially enclosed by the arc protectors 6 of the same pair 60) can further significantly improve the performance of the fuse 2 compared to the prior art. In the example shown, the perforations 80 are formed on each side of the reduced section 46A. In a variant not shown, one or more perforations 80 are formed on one side of the reduced section 46A and in the vicinity of the reduced section 46A, and at least one perforation 80 also contributes to the extinction of the arc.

[0126] In the example shown, for the purpose of illustrating the present invention, the perforations 80 and the arc protector 6 are only provided on either side of the reduced section 46A located in the middle of the fuse blade 4. Of course, when the fuse blade 4 includes reduced sections 46 other than the reduced section 46A, if necessary, other perforations of the perforation 80 type and other arc protection devices of the arc protector 6 type can be placed in the vicinity of these reduced sections 46.

[0127] According to a variant not shown, the perforations 80 are separated from each other by two or more reduced sections 46 and / or reduced sections of the 46A type. As described above, the perforations 80 and the arc protector 6 have a shape with precise dimensions, which can be changed especially according to the size and rating of the fuse 2 and the size of the hole 44 of the reduced section 46A.

[0128] Especially by Figure 8 The manufacturing method of the fuse 2 described thus includes: step 800 includes providing at least one perforation 80 near the reduced section 46A on one side of the transverse plane P4 in the fuse blade 4.

[0129] Then, the method comprises step 802, which includes assembling, on each main surface of the fuse link 4 near the reduced section 46A, the two arc protectors 6 of the same pair 60 such that the perforation 80 is at least partially closed by the arc protectors 6. When the length of the perforation 80 is greater than the length L6 of the arc protectors 6, a front vent 84 and / or a rear vent 82 are provided.

[0130] When the arc protectors 6 are assembled to the fuse link 4 by bonding during the assembly step 802, the manufacturing process comprises a step 804 prior to the assembly step 802, which includes manufacturing the two arc protectors 6 of the first pair 60. The arc protectors 6 are made of a preformed elastic material, in particular a crosslinked elastomer such as silicone, and each has a flat inner surface 66. Non - restrictively, the arc protectors 6 are manufactured, for example, by molding, and the inner surface 66 is optionally corrected by machining. According to another example, a calibrated strip of an elastic material is manufactured, for example, by calendering, the width of the calibrated strip being equal to the width of the fuse link 4 on which the arc protectors 6 are intended to be bonded, and the thickness of the calibrated strip being equal to the thickness L7 of the arc protectors 6. Then the arc protectors 6 are cut from the calibrated strip. One or more surfaces of the arc protectors 6 can be machined to correct their geometry, in particular the inner surface 66 (which is preferably flat to facilitate the bonding of the adhesive layer 72) and the front surface 62 facing the reduced section 46A.

[0131] Then, during the assembly step 802, an adhesive layer 72 is inserted between the inner surface 66 of each arc protector 6 and each main surface of the fuse link 4, and then the arc protectors 6 are placed on the fuse link near the reduced section 46A. The arc protectors 6 are on the same side of the transverse plane P4, and the front surface 62 of the arc protectors 6 is oriented towards the reduced section 46A such that the distance L8 between the front surface 62 of each arc protector 6 and the closest boundary line 70 is between 1 mm and 15 mm.

[0132] Figure 9 and Figure 10Shows a fourth embodiment of the fuse insert 4 and the arc protector 6. Similar to the third embodiment, the perforations 80 formed near the reduced section 46A extend from the front surface 62 and the rear surface 64 of the arc protector 6 to form a front vent 84 and a rear vent 82 respectively. Each perforation 80 is at least partially enclosed by the inner surfaces 66 of two arc protectors 6 of the same pair 60, and each perforation 80 leaves a chamber between two arc protectors 6 of the same pair 60. In other embodiments, the arc protector 6 of the fourth embodiment is made of an elastic material (silicone resin in this case) and is associated in pairs 60 and fixed to the fuse insert 4 through an adhesive layer 72, which is inserted between the fuse insert and the inner surface 66 of each arc protector 6 of the corresponding pair 60.

[0133] The main difference between the fuse insert 4 and the arc protector 6 of the fourth embodiment and the previous embodiments is that the perforations 80 are elongated ellipses, and their lengths extend parallel to the longitudinal axis A2 of the fuse 2. On the other hand, here, the fuse insert 4 has folding portions 86 at the front surface 62 and the rear surface 64 of the arc protector 6. In the illustrated example, the folding portions 86 are located in a plane parallel to the transverse plane P4. The front vent 84 and the rear vent 82 extend above these folding portions 86. Therefore, the direction of the front vent 84 is towards the reduced section 46A. In the illustrated example, the direction of the rear vent 82 of each pair 60 of arc protectors 6 is towards the corresponding reduced section 46. According to the nomenclature used in this specification, the rear vent 82 relative to the reduced section 46A is thus a front vent relative to one of the reduced sections 46.

[0134] Compared with the fuse insert 4 without folding portions, this structure of the fuse insert 4 including the folding portions 86 makes the structure more compact.

[0135] In all the illustrated embodiments, the arc protector 6 is made of a prefabricated elastic material, especially an elastomeric material such as silicone resin. Optionally, the arc protector 6 may include mineral and / or organic particles, which are added to the elastic material in the form of powder and / or fiber. These particles are used to adjust the properties of the material of the arc protector 6, for example, to adjust the Shore hardness of the material and / or to serve as mechanical reinforcement. Then, the material of the arc protector 6 is a reinforced material, also called a composite material, including a matrix made of an elastic material, especially a matrix made of an elastomeric material such as silicone resin. Contrary to the reinforced material, the material without added particles is called the "raw material".

[0136] According to a variant not shown, the arc protector is made of a foamed elastomeric material, i.e., a material containing air bubbles and having an average porosity greater than 50%, preferably greater than 60%, more preferably greater than 70%. The average porosity of a given part is defined as the ratio of the volume of air bubbles contained in the part to the total volume of the part.

[0137] According to another variant not shown, the arc protector 6 comprises a number of layers of material stacked on one another. At least one layer is made of an elastic material as described above, in particular an elastomeric material such as silicone. According to an example, these layers have different characteristics, in particular different hardness characteristics, and these layers of material are advantageously assembled with one another by bonding.

[0138] Many other embodiments are possible.

[0139] In particular, the features of the fuse insert 4 and the arc protector 6 according to the invention, and in particular the structural features of the arc protector and its manufacturing method, can be implemented independently of the body 20, which comprises a frame 48 as described above and can be implemented in the form of a conventional fuse body. In particular, the perforation 80 can be used independently of the frame 48.

[0140] Where technically feasible, any feature described for the above embodiments or variants can be implemented in other embodiments or variants described above.

Claims

1. A fuse (2), comprising: - at least one fuse tab (4) formed in a sheet shape, having two opposite main surfaces extending along the longitudinal axis of the fuse tab, each fuse tab including a portion in which a reduced section (46, 46A) is formed, the reduced section defining a plane (P4) transverse to the fuse tab; - two connection terminals (22), each terminal being connected to each fuse tab, - a pair (60) of arc protectors (6) made of an elastic material and associated together, each in the same pair of arc protectors being placed opposite each other on the respective main surface of the same fuse tab, each arc protector including an inner surface (66) facing the fuse tab, a front surface (62) facing the reduced section, and a rear surface (64) facing away from the reduced section, wherein at least one perforation (80) is formed near the reduced section (46A) of the fuse tab (4), each said perforation being at least partially closed by the inner surfaces (66) of two arc protectors (6) in the same pair (60), and each perforation forming a chamber between the two arc protectors in the same pair; characterized in that, for each fuse tab (4), the surface section of a set of perforations (80) measured along the longitudinal axis (A2) of the fuse tab is greater than five times the smallest surface section of the reduced section provided on the fuse tab.

2. The fuse (2) according to claim 1, wherein, For each fuse tab (4), the surface section of the set of perforations (80) is greater than ten times the smallest surface section of the reduced section provided on the fuse tab.

3. The fuse (2) according to claim 1 or 2, wherein perforations (80) are formed on each side of the reduced section (46A) in the fuse insert (4), and wherein, In addition to the first pair (60) of arc protectors (6), the fuse includes a second pair (60) of arc protectors, and each of the first pair of arc protectors and the second pair of arc protectors at least partially closes the perforations formed on each side of the reduced section.

4. The fuse (2) according to claim 1 or 2, wherein, The perforation (80) has an elongated shape and is arranged parallel to the longitudinal axis (A2) of the fuse tab along its length.

5. The fuse (2) according to claim 1 or 2, wherein, The perforation (80) extends parallel to the longitudinal axis (A2) of the fuse tab (4) beyond the rear surface (64) of the arc protector (6) to form a rear vent (82).

6. The fuse (2) according to claim 5, wherein, The length (L82) of the rear vent (82) is between 0.1 mm and 10 mm.

7. The fuse (2) according to claim 6, wherein, The length (L82) of the rear vent (82) is between 0.5 mm and 8 mm.

8. The fuse (2) according to claim 7, wherein, The length (L82) of the rear vent (82) is between 1 mm and 5 mm.

9. The fuse (2) according to claim 1 or 2, wherein, The perforation (80) extends parallel to the longitudinal axis (A2) of the fuse tab (4) beyond the front surface (62) of the arc protector (6) to form a front vent (84).

10. The fuse (2) according to claim 9, wherein, The length (L84) of the front vent (84) is between 0.1 mm and 5 mm.

11. The fuse (2) according to claim 10, wherein, The length (L84) of the front vent (84) is between 1 mm and 3 mm.

12. The fuse (2) according to claim 1 or 2, wherein, The length (L6) of each arc protector (6) between the front surface (62) and the rear surface (64) is between 5 mm and 30 mm.

13. The fuse (2) according to claim 1 or 2, wherein, The distance (L8) between the front surface (62) of the arc protector (6) and the boundary line (70) of the opposite reduced section (46A) is between 0.5 mm and 20 mm.

14. The fuse (2) according to claim 13, wherein, The distance (L8) between the front surface (62) of the arc protector (6) and the boundary line (70) of the opposite reduced section (46A) is between 1 mm and 15 mm.

15. The fuse (2) according to claim 13, wherein, The distance (L8) between the front surface (62) of the arc protector (6) and the boundary line (70) of the opposite reduced section (46A) is between 2 mm and 12 mm.

16. The fuse (2) according to claim 1 or 2, wherein, The arc protector (6) is made of a material having a hardness measured in Shore A hardness between 20 and 90.

17. The fuse (2) according to claim 16, wherein, The arc protector (6) is made of a material having a hardness measured in Shore A hardness between 40 and 70.

18. The fuse (2) according to claim 1 or 2, wherein, The arc protector (6) is made of an elastomeric material.

19. The fuse (2) according to claim 18, wherein, The arc protector (6) is made of silicone resin.

20. The fuse (2) according to claim 1 or 2, wherein for at least the first pair (60) of arc protectors (6), the arc protectors (6) are made of a preformed material, and an adhesive layer (72) is inserted between the fuse insert (4) and the inner surface (66) of each of the pair of arc protectors (6), the inner surface facing one of the main surfaces of the fuse insert, so as to fix each arc protector to the fuse insert.

21. The fuse (2) according to claim 1 or 2, wherein, The fuse includes a frame (48), the frame (48) is received in a chamber (V20) of the body (20) of the fuse, and the movement of the fuse insert (4) relative to the body is restricted by means of spacers (52) and / or gaskets (58).

22. A method of manufacturing a fuse (2) according to any one of claims 1-21, the fuse including at least one fuse insert (4) having a reduced section (46, 46A) that defines a transverse plane (P4) transverse to the fuse insert; wherein the method includes the following steps: - Providing (800) at least one perforation (80) in the fuse insert (4) on one side of the transverse plane (P4), - Assembling (802) the first pair (60) of two arc protectors (6) on the respective main surfaces of the fuse insert (4) near the reduced section (46, 46A) so that each perforation (80) is at least partially closed by the arc protector (6), and the distance (L8) between the front surface (62) of each arc protector (6) and the boundary line (70) of the opposite reduced section is between 1 mm and 15 mm.

23. The manufacturing method according to claim 22, wherein, The method comprises the following steps: before the assembling step (802), manufacturing (804) a first pair (60) of two arc protectors (6), the arc protectors (6) being made of a crosslinked elastomeric material and having a flat inner surface (66), and in the assembling step, inserting an adhesive layer (72) between the inner surface (66) of each arc protector and the corresponding main surface of the fuse blade so as to bond the first pair (60) of two arc protectors (6) to the fuse blade.

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