Preparation method of knife type contact fuse

Abstract

The invention provides a preparation method of a knife-type contact fuse. The preparation method is used for preparing the knife-type contact fuse comprising a shell, a melt unit and an active heat dissipation structure. The shell is prepared from aluminum nitride ceramic powder, graphene, multi-walled carbon nanotubes, silicon-carbon alloy powder, zirconium oxide or aluminum oxide nanoparticles, an interface coupling agent and a dispersing aid, so that insulation and mechanical strength are guaranteed, excellent thermal conductivity is achieved, heat generated by a melt unit can be quickly dispersed, local temperature rise is reduced, and thermal aging is delayed. The side wall of the cavity is provided with a heat-conducting layer and filled with heat-conducting silicone grease to form a low-heat-resistance heat transfer path, so that the overall heat dissipation efficiency is improved. The external detachable active heat dissipation fins are fixed through magnetic attraction, the heat exchange area is increased, and flexible and efficient heat dissipation is achieved. Separators and multi-layer metal sheet grid type arc extinguishing structures are arranged between the fusing sections, electric arcs are effectively segmented and cooled, thermal coupling and electric arc crosstalk are restrained, it is ensured that the fusing position is controllable in the middle narrow neck area, and rapid and stable fusing is achieved.

Description

Technical Field

[0001] This invention relates to the field of fuse technology, specifically to a method for manufacturing a knife-type contact fuse. Background Technology

[0002] As an important overcurrent protection component, fuses are widely used in power distribution systems, power electronic equipment, rail transit, and new energy systems. Their core function is to quickly cut off the current and protect equipment safety when a circuit experiences overload or short circuit faults. Especially in high-voltage and high-current environments, the fuse's operating speed, fusing reliability, thermal stability, and arc-extinguishing capability directly affect the system's operational safety and efficiency.

[0003] Currently, some fuses have improved their heat dissipation performance by adding heat sinks or optimizing the housing structure, but the improvement in heat dissipation effect is still limited. In high-performance power systems, insufficient heat dissipation of fuses can lead to heat accumulation inside the housing, forming a high-temperature zone. Prolonged high temperatures will accelerate the aging process of the fuse material, such as oxidation and grain coarsening, thus shortening the fuse's lifespan and potentially causing a decline in housing insulation performance and structural deformation. Furthermore, the compact structure of multiple fuse segments within a fuse makes effective thermal and electromagnetic isolation difficult to achieve. The high-temperature arc generated during the fusing process can easily spread, causing thermal coupling or arc crosstalk between adjacent fuse segments, thereby affecting the consistency and safety of the fusing response.

[0004] Therefore, there is an urgent need to provide a new method for manufacturing knife-type contact fuses to produce fuses with high heat dissipation performance, high fusing stability and strong arc extinguishing capability, and to solve the problems of low heat dissipation efficiency and unstable fusing response in the existing technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, a method for manufacturing a knife-type contact fuse is provided, which can be used to prepare a knife-type contact fuse with reliable structure, strong heat dissipation performance and high arc extinguishing capability.

[0006] A method for manufacturing a knife-type contact fuse, comprising a housing, a fusible element unit, and an active heat dissipation structure. The housing has annular metal rings on its four outer walls, and a cavity within the housing. A thermally conductive layer is disposed on the sidewall of the cavity, and thermally conductive silicone grease is coated between the thermally conductive layer and the sidewall of the cavity. The fusible element unit is housed within the cavity and includes multiple parallel-connected fusing segments. Each fusing segment has at least one narrow neck region formed by cross-sectional area reduction. A knife-type contact is connected to each end of the parallel-connected fusing segments, and a separator is provided between each fusing segment. An arc-extinguishing structure is provided on one side facing the fuse section. The arc-extinguishing structure includes a multi-layer metal grid. The active heat dissipation structure includes a connecting base and multiple heat dissipation fins arranged perpendicularly to the connecting base. An annular magnetic attractor is provided on the connecting base and magnetically connected to the annular metal ring. The preparation method of the knife-type contact fuse includes the following steps: (1) Prepare the composite material slurry for making the shell: Mix the following components according to the mass percentage to prepare the material mixture for making the shell: aluminum nitride ceramic powder: 30%~45%; thermosetting high temperature resin: 35%~50%; graphene sheets: 0.5%~1.5%; multi-walled carbon nanotubes: 0.3%~ 1.2%; silicon-carbon alloy powder: 3%~10%; zirconium oxide or alumina nanoparticles: 2%~6%; interface coupling agent and dispersant: 0.1%~2%; the mixture is mixed under high shear to form a composite material slurry suitable for injection molding or hot pressing; (2) molding shell: the composite material slurry is used to prepare the shell by injection molding or hot pressing process. The shell is a hollow structure, and metal rings are embedded on its four outer walls; (3) setting a heat-conducting structure: a heat-conducting layer is set on the side wall surface of the inner cavity of the shell. The heat-conducting layer is installed to the cavity of the shell by dispensing or snapping, and heat-conducting silicone grease is filled between it and the side wall of the cavity; (4) assembling the melt Unit and partition structure: The melting unit is fitted with each melting segment on the partition, which is composed of a partition plate and a connecting plate. The partition plate is provided with a grid-type arc extinguishing structure composed of multiple metal sheets between each pair of melting segments. Then the melting unit and the partition are installed into the cavity of the shell. The melting unit includes multiple melting segments arranged in parallel. Each melting segment has a narrow neck area in the middle. (5) Install active heat dissipation structure: The active heat dissipation structure is installed on the outer wall of the shell. The active heat dissipation structure includes a connecting base and multiple vertically arranged high thermal conductivity heat dissipation fins. The connecting base is provided with an annular magnetic suction component. The annular magnetic suction component is magnetically connected to the metal ring on the outer wall of the shell.

[0007] Preferably, the thermosetting high-temperature resin is a modified phenolic resin or an epoxy resin with heat resistance, and its glass transition temperature is not lower than 180°C.

[0008] Preferably, the shell is formed using a vacuum-assisted hot pressing process.

[0009] Preferably, the separator includes multiple partitions and a connecting plate connected between the partitions. The top of the connecting plate is recessed to the bottom side and a limiting groove is provided. The fusible segment is engaged in the limiting groove. The partition is provided with the arc extinguishing structure.

[0010] Preferably, the width of the partition is equal to or slightly smaller than the gap between the sidewalls of the cavity.

[0011] Preferably, in the arc-extinguishing structure, there is a gap between each layer of the multi-layer metal sheet grid, and the metal sheets are staggered in the longitudinal direction.

[0012] Preferably, the metal grid of the arc-extinguishing structure is made of stainless steel, and its surface is provided with an oxide layer to enhance its high-temperature resistance and insulation performance.

[0013] Preferably, the separator is a ceramic insulating separator, which has multiple raised, diffused arc tooth structures on the side facing the fused section.

[0014] Preferably, the fused section is made of silver-coated copper composite material and is covered with an anti-oxidation coating.

[0015] Preferably, the thermally conductive layer is a graphene thermally conductive coating or a copper plate thermally conductive layer with an insulating layer on its surface, and the thermally conductive layer is connected to the side wall of the cavity by adhesive application or clips.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for manufacturing a knife-type contact fuse. The knife-type contact fuse comprises a housing, a fusible element, and an active heat dissipation structure. The housing is made of a mixture of aluminum nitride ceramic powder, graphene sheets, multi-walled carbon nanotubes, silicon-carbon alloy powder, zirconium oxide or alumina nanoparticles, interfacial coupling agents, and dispersing agents. This allows the housing to maintain good insulation and mechanical strength while possessing excellent thermal conductivity, facilitating the rapid conduction and dispersion of heat generated by the fusible element during current carrying and fusing, reducing localized temperature rise inside the housing, delaying material thermal aging, and thus extending the fuse's service life. Simultaneously, a thermally conductive layer is provided on the inner wall of the housing cavity, and thermally conductive silicone grease is filled between the thermally conductive layer and the cavity sidewall, forming a continuous, low-thermal-resistance heat transfer path. This allows the heat generated by the fusible element to be transferred to the outside of the housing more efficiently, further improving overall heat dissipation efficiency and preventing drift in fusing characteristics or degradation of insulation performance due to heat accumulation. The active heat dissipation structure on the outer side of the housing is detachable, and the heat dissipation fins are reliably fixed to the outer wall of the housing by magnetic attraction. This not only increases the heat exchange area but also achieves efficient heat dissipation without changing the fuse body structure, which is beneficial for flexibly configuring heat dissipation capacity under different application conditions. In addition, by setting separators between multiple parallel fuse segments and arranging a multi-layer metal grid arc-extinguishing structure on the side of the separators facing the fuse segments, this application can effectively divide, elongate, and cool the generated arc at the moment of melting, significantly suppressing arc propagation and thermal coupling and arc crosstalk between adjacent fuse segments, thereby improving the consistency and safety of the melting response. The narrow neck region set in the middle of each fuse segment makes the melting position controllable, which helps to achieve fast and stable melting action. Therefore, the knife-type contact fuse prepared by the method of this invention has excellent performance in terms of heat dissipation capacity, melting reliability, and safety under high current and high load conditions. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the knife-type contact fuse according to the present invention; Figure 2 This is a schematic diagram of the front view of the knife-type contact fuse according to the present invention; Figure 3 This is a front view schematic diagram of the knife-type contact fuse according to the present invention; Figure 4 This is a partial top view of the separator and melt unit described in this invention; Figure 5 This is a schematic diagram of the left side of the active heat dissipation structure described in this invention; in: 10-Housing, 20-Knife-shaped contact, 30-Active heat dissipation structure, 40-Annular metal ring, 50-Fuse section, 51-Narrow neck area, 60-Separator, 70-Arc extinguishing structure, 31-Connecting base, 32-Heat dissipation fins, 61-Baffle, 62-Connecting plate, 63-Limiting groove. Detailed Implementation

[0018] The embodiments described below are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] See Figures 1-5 This embodiment provides a method for manufacturing a knife-type contact fuse, which is used to manufacture a knife-type contact fuse. The knife-type contact fuse includes a housing 10, a fusible element unit, and an active heat dissipation structure 30. The components are arranged in a coordinated manner to achieve a comprehensive improvement in the heat dissipation performance and fusing reliability of the fuse under high current conditions.

[0020] Specifically, the shell 10 has a hollow structure, forming an internal cavity for accommodating the molten metal units. Each of the four outer walls of the shell 10 is provided with an annular metal ring 40, which is fixedly connected to the shell 10, providing a magnetic connection base for the subsequent installation of the active heat dissipation structure 30. A thermally conductive layer is provided on the sidewall of the cavity, arranged along the sidewall to increase the effective heat exchange area between the thermally conductive layer and the internal molten metal units. Thermally conductive silicone grease is applied between the thermally conductive layer and the sidewall of the cavity, filling the gap between them and reducing interfacial thermal resistance, thereby forming a continuous and stable heat transfer path, which facilitates the efficient conduction of heat generated inside the cavity to the shell 10.

[0021] The fusible element unit is housed within the cavity and comprises multiple fusible segments 50 arranged in parallel. Each fusible segment 50 has at least one narrow neck region 51 formed by cross-sectional area reduction. The narrow neck region 51 defines the fusing position, making the fusing process more controllable and stable. A knife-shaped contact 20 is connected to each end of the multiple fusible segments 50 connected in parallel to achieve a reliable electrical connection with an external circuit, meeting the installation and usage requirements of knife-shaped contact fuses.

[0022] A separator 60 is provided between adjacent fusible segments 50 to physically isolate each fusible segment 50 and reduce the possibility of mutual interference during the fusing process. An arc-extinguishing structure 70 is provided on the side of each separator 60 facing the fusible segment 50, and the arc-extinguishing structure 70 includes multiple layers of metal sheet grids. By dividing, elongating, and cooling the electric arc generated at the moment of fusing through the multiple layers of metal sheet grids, arc propagation can be effectively suppressed, improving the safety and reliability of the fusing process.

[0023] The active heat dissipation structure 30 is disposed on the outside of the housing 10 to further dissipate heat conducted from the inside of the housing 10. The active heat dissipation structure 30 includes a connecting base 31 and multiple heat dissipation fins 32 perpendicularly arranged to the connecting base 31. The multiple heat dissipation fins 32 are distributed along the connecting base 31 to significantly increase the heat exchange area with the external air. An annular magnetic attractor is provided on the connecting base 31, and the annular magnetic attractor is magnetically connected to an annular metal ring 40 on the outer wall of the housing 10, allowing the active heat dissipation structure 30 to be reliably fixed to the outside of the housing 10, while facilitating disassembly and maintenance. Therefore, the knife-type contact fuse manufactured by this invention, while maintaining the traditional knife-type contact 20 installation method and electrical connection form, achieves the coordinated arrangement of the internal heat conduction structure, the arc extinguishing structure 70, and the external active heat dissipation structure 30, effectively improving the fuse's heat dissipation capacity, fusing stability, and overall operational reliability under continuous current carrying and fusing conditions.

[0024] Specifically, the method for manufacturing the knife-type contact fuse described in this application includes the following steps: Prepare the composite material slurry for making the shell 10: Mix the following components in the following mass percentages to prepare the material mixture for making the shell 10: aluminum nitride ceramic powder: 30%–45%; thermosetting high-temperature resin: 35%–50%; graphene sheets: 0.5%–1.5%; multi-walled carbon nanotubes: 0.3%–1.2%; silicon-carbon alloy powder: 3%–10%; zirconium oxide or alumina nanoparticles: 2%–6%; interfacial coupling agent and dispersant: 0.1%–2%; The mixture is then subjected to high-shear mixing to form a composite material slurry suitable for injection molding or hot pressing; By compounding aluminum nitride ceramic powder, thermosetting high-temperature resin, graphene sheets, multi-walled carbon nanotubes, silicon-carbon alloy powder, and zirconium oxide or alumina nanoparticles in a specific mass percentage, the shell 10 material maintains good formability while also possessing high thermal conductivity, high mechanical strength, and high-temperature resistance. The addition of interfacial coupling agents and dispersants helps to improve the interfacial bonding state between inorganic fillers and resin matrix, prevent filler agglomeration, and thus ensure that the composite slurry has a uniform component distribution and stable rheological properties after high shear mixing, providing a good foundation for subsequent injection molding or hot pressing.

[0025] Shell 10: The shell 10 is prepared by injection molding or hot pressing of the composite material slurry. The shell 10 is a hollow structure, with annular metal rings 40 embedded in its four outer walls. By preparing the shell 10 into a hollow structure using injection molding or hot pressing, the structural strength and dimensional stability of the shell 10 can be guaranteed while achieving precise shaping of the internal cavity. The annular metal rings 40 embedded in the four outer walls of the shell 10 during the molding process can form a reliable mechanical connection with the shell 10, enabling the shell 10 to maintain its insulation performance while having a metal connection interface. This provides a stable force and positioning foundation for the subsequent magnetic installation of the active heat dissipation structure 30, improving the reliability and consistency of the overall assembly from a structural perspective.

[0026] A thermally conductive structure is provided: a thermally conductive layer is provided on the side wall surface of the inner cavity of the housing 10. The thermally conductive layer is installed to the cavity of the housing 10 by dispensing or snap-fitting, and thermally conductive silicone grease is filled between the thermally conductive layer and the side wall of the cavity. The provision of the thermally conductive layer on the side wall surface of the inner cavity of the housing 10 and the filling of thermally conductive silicone grease between the thermally conductive layer and the side wall of the cavity allows the thermally conductive layer to form a tight thermal contact with the housing 10. By providing the thermally conductive layer, the effective heat transfer area between the interior of the housing 10 and the fuse unit can be significantly increased. The thermally conductive silicone grease can fill the microscopic gaps and reduce the interfacial contact thermal resistance, thereby forming a stable and continuous heat conduction path. This facilitates the rapid conduction of heat generated by the fuse unit during current carrying and melting to the outside of the housing 10, reduces the internal temperature rise of the cavity, and improves the thermal stability of the fuse during long-term operation.

[0027] Assemble the melt unit and the partition structure: The melt unit's fusible segments 50 are engaged on the partition 60, which consists of a partition plate 61 and a connecting plate 62. A multi-layered metal grid-type arc-extinguishing structure 70 is provided on the partition plate 61 between each pair of fusible segments 50. The melt unit and partition 60 are then installed into the cavity of the housing 10. The melt unit includes multiple fusible segments 50 arranged in parallel, each with a narrow neck region 51 in the middle. By engaging the fusible segments 50 in the melt unit on the partition 60 and using the partition 60 (composed of the partition plate 61 and the connecting plate 62) to isolate adjacent fusible segments 50, the interaction of heat and arc between the fusible segments 50 can be structurally limited. The multi-layered metal sheet grid-type arc-extinguishing structure 70 on the partition 61 can divide, elongate, and cool the generated arc at the moment of melting, effectively suppressing arc propagation and reducing the impact of arc energy on the casing 10 and other melting sections 50. The narrow neck region 51 in the middle of each melting section 50 can achieve precise control of the melting position and melting time, so that multiple parallel melting sections 50 have good consistency during operation, thereby improving the overall breaking capacity and safety performance of the fuse.

[0028] The active heat dissipation structure 30 is installed on the outer wall of the housing 10. The active heat dissipation structure 30 includes a connecting base 31 and multiple vertically arranged high thermal conductivity heat dissipation fins 32. The connecting base 31 is equipped with an annular magnetic chuck, which magnetically connects to a metal ring on the outer wall of the housing 10. By installing the active heat dissipation structure 30 on the outer wall of the housing 10 and using the annular magnetic chuck on the connecting base 31 to the annular metal ring 40 on the outer wall of the housing 10 for magnetic connection, the heat dissipation structure can be quickly installed and stably fixed without additional fasteners. The multiple vertically arranged high thermal conductivity heat dissipation fins 32 significantly increase the heat exchange area with the outside air, allowing the heat conducted by the housing 10 to be released more efficiently to the external environment, thereby reducing the overall temperature rise of the fuse under continuous current-carrying conditions. Simultaneously, the magnetic connection method facilitates the replacement or maintenance of the heat dissipation structure according to different usage environments, improving the product's applicability and flexibility.

[0029] It should be noted that in step (1), the aluminum nitride ceramic powder is set to 30% to 45% and is used as the main thermally conductive filler of the shell 10 material. It has high thermal conductivity and good electrical insulation properties. Within this range, the aluminum nitride ceramic powder can form a continuous or semi-continuous thermally conductive skeleton in the resin matrix, effectively improving the overall thermal conductivity of the shell 10. When its content is lower than the lower limit of this range, it is difficult to effectively establish thermal channels, and the heat dissipation performance of the shell 10 is limited. When its content is higher than the upper limit of this range, it is easy to cause a significant increase in the viscosity of the slurry, affecting the molding fluidity and product density, which is detrimental to the structural strength and processing stability of the shell 10.

[0030] The high-temperature solid resin is set at 35%–50% as the matrix material of the composite material, used to coat and fix various thermally conductive fillers, giving the shell the necessary structural strength, electrical insulation properties, and heat resistance. Within this range, the resin matrix can provide a stable interfacial bond between the thermally conductive fillers while ensuring sufficient mechanical strength and moldability. If the resin content is too low, it will be difficult to effectively coat the fillers, leading to increased material brittleness; if the resin content is too high, it will weaken the effective proportion of the thermally conductive fillers, which is not conducive to the overall thermal conductivity.

[0031] The graphene sheets are set at 0.5% to 1.5%, and the multi-walled carbon nanotubes are set at 0.3% to 1.2%. As high specific surface area thermally conductive reinforcing phases, the two are synergistically distributed in the resin matrix within this ratio range, which can construct a multi-scale thermally conductive network with sheet-line bonding, thereby effectively reducing the interfacial thermal resistance inside the composite material and improving the heat conduction efficiency in different directions. When their content is lower than the range, it is difficult to form an effective thermally conductive network structure, while when their content is too high, agglomeration is likely to occur, which will affect the material uniformity and insulation performance.

[0032] The silicon-carbon alloy powder is set at 3% to 10% to improve the thermal stability and structural strength of the shell 10 material, and to participate in the construction of the thermal conduction path as an auxiliary thermally conductive filler. Within this ratio range, the comprehensive thermomechanical properties of the composite material can be improved without significantly increasing the brittleness of the material.

[0033] Zirconia or alumina nanoparticles are set at 2% to 6% to fill the microscopic voids between the thermally conductive filler and the resin matrix, improve the overall density of the material, and enhance the thermal shock resistance and crack resistance of the housing 10, thereby helping to improve the structural reliability of the fuse under high temperature and high current conditions.

[0034] The interface coupling agent and dispersant are set at 0.1% to 2% to improve the interfacial compatibility between various inorganic fillers and the resin matrix, inhibit the aggregation of graphene sheets, multi-walled carbon nanotubes and nanoparticles, and ensure that each component can be uniformly dispersed within the specified ratio range, thereby ensuring the stability and consistency of the composite slurry during injection molding or hot pressing.

[0035] Preferably, the thermosetting high-temperature resin is a modified phenolic resin or a heat-resistant epoxy resin with a glass transition temperature of not less than 180°C. By selecting the above-mentioned thermosetting high-temperature resin as the resin matrix of the composite material of the shell 10, the resulting shell 10 can maintain stable mechanical properties and dimensional stability under high-temperature conditions, effectively avoiding problems such as softening, creep, or structural deformation caused by temperature rise. The modified phenolic resin or the heat-resistant epoxy resin has good heat aging resistance and electrical insulation properties in high-temperature environments, which can meet the usage requirements of knife-type contact fuses under high-temperature conditions generated during long-term current carrying or short-circuit melting. At the same time, the thermosetting high-temperature resin with a glass transition temperature of not less than 180°C, after being compounded with thermally conductive fillers such as aluminum nitride ceramic powder, graphene sheets, and multi-walled carbon nanotubes, can maintain a stable interfacial bonding state under high-temperature conditions, preventing the thermally conductive fillers from loosening or the interface from delaminating due to the deterioration of the resin matrix properties, thereby helping to maintain the overall thermal conductivity and structural reliability of the shell 10 material. This results in a knife-type contact fuse with enhanced safety and extended service life in high-current, high-power-density operating environments. Preferably, the housing 10 is formed using a vacuum-assisted hot-pressing process.

[0036] Preferably, the separator 60 includes a plurality of partitions 61 and a connecting plate 62 disposed between the partitions 61. The partitions 61 are spaced apart along the length of the cavity to separate the plurality of parallel-connected fusion segments 50 within the cavity, thereby achieving independent arrangement of each fusion segment 50 structurally and reducing the possibility of thermal coupling and arc interference between adjacent fusion segments 50 during the fusing process. The connecting plate 62 is disposed between adjacent partitions 61 to connect and position the plurality of partitions 61 as a whole, thereby improving the overall structural stability and assembly strength of the separator 60. A limiting groove 63 is recessed from the top to the bottom of the connecting plate 62, and the limiting groove 63 is used for installing and positioning the fusion segments 50. During assembly, the fuse segment 50 is engaged within the limiting groove 63, effectively limiting each fuse segment 50 in both the radial and axial directions. This prevents displacement or deformation due to vibration or thermal shock during transportation, installation, or fusing, thereby ensuring the relative positional stability of the fuse segment 50 within the fuse and the reliability of the electrical connection.

[0037] Meanwhile, the partition 61 is provided with the arc-extinguishing structure 70, which is arranged opposite to the corresponding fusible segment 50. When the fusible segment 50 melts and generates an arc, the arc-extinguishing structure 70 can divide, elongate, and cool the arc, thereby accelerating the extinguishing of the arc and suppressing the spread and propagation of the arc within the cavity. By directly setting the arc-extinguishing structure 70 on the partition 61, the partition 60 not only achieves structural isolation of the fusible segment 50 but also has an arc-extinguishing function, which is beneficial to improving the fusing safety and operational reliability of the knife-type contact fuse under high voltage and high current conditions.

[0038] Preferably, the width of the partition 61 is equal to or slightly smaller than the gap between the sidewalls of the cavity.

[0039] Preferably, the multiple layers of metal sheet grids in the arc-extinguishing structure 70 are arranged sequentially along the direction in which the electric arc may propagate, with gaps between adjacent layers. By forming gaps between the metal sheet grids, the electric arc generated during the melting process is repeatedly divided and stretched as it passes through the arc-extinguishing structure 70, thereby effectively extending the arc channel length, reducing the arc energy density, and facilitating rapid cooling and extinguishing of the arc. Simultaneously, the metal sheets are staggered in the longitudinal direction, with adjacent layers not aligned in a straight line, forcing the arc to change its propagation path as it passes through the multiple layers of metal sheet grids, forming a tortuous arc channel. This staggered arrangement further suppresses the linear propagation trend of the arc, enhances the arc dispersion effect, reduces concentrated ablation of individual metal sheets by the arc, and improves the overall high-temperature resistance and service life of the arc-extinguishing structure 70. Therefore, by adopting a multi-layer metal grid structure with gaps between layers and longitudinal staggered arrangement in the arc extinguishing structure 70, the arc extinguishing structure 70 can still achieve efficient arc extinguishing even with limited structural dimensions, which is beneficial to improving the fusing reliability and safety performance of knife-type contact fuses under high voltage and high current conditions.

[0040] Preferably, the metal grid of the arc-extinguishing structure 70 is made of stainless steel. Stainless steel has good high-temperature resistance, mechanical strength, and thermal shock resistance. When the fuse experiences an overload or short-circuit fault and generates an arc, it can withstand the high temperature released by the arc instantaneously without melting, deformation, or structural damage, thus ensuring the structural stability and reliability of the arc-extinguishing structure 70 during repeated operations. Simultaneously, the surface of the metal grid is provided with an oxide layer. By forming a stable oxide layer on the surface of the metal sheet, an insulating layer with certain insulating properties can be formed between the metal sheet and the arc, effectively reducing the probability of the arc slipping or reigniting on the surface of the metal sheet, thereby improving the arc suppression effect during the arc extinguishing process. The oxide layer can also reduce the electrical conductivity of the metal sheet surface, weaken the adhesion of the arc to the metal sheet, and promote the rapid dissipation of arc energy.

[0041] Preferably, the separator 60 is a ceramic insulating separator 60. Ceramic materials have excellent electrical insulation properties, high temperature resistance, and arc erosion resistance. When the fuse experiences overcurrent or short-circuit faults, it can maintain stable physical and electrical properties under high temperature and strong electric field environments, thereby effectively blocking the electrical connection between adjacent fuse segments 50, preventing the arc from spreading between different fuse segments 50, and improving the safety and reliability of the fusing process. The ceramic insulating separator 60 has multiple raised arc-dispersing tooth structures on the side facing the fuse segment 50. During the fusing process, the raised arc-dispersing tooth structures can divide, guide, and stretch the generated arc, causing the arc path to make multiple turns, thereby increasing the effective length of the arc and promoting the rapid attenuation of arc energy during propagation. Through the synergistic effect of multiple raised arc-dispersing tooth structures, the phenomenon of concentrated arc combustion can be effectively suppressed, the peak arc temperature can be reduced, and the ablation effect of the arc on the fuse segment 50 and the separator 60 body can be reduced. Furthermore, the raised arc-dispersing tooth structure enhances the contact area between the arc and the surrounding air or the arc-extinguishing structure 70, facilitating the rapid diffusion and dissipation of arc heat, thereby shortening the arc duration and improving the arc-extinguishing efficiency of the fuse. By providing the raised arc-dispersing tooth structure on the ceramic insulating separator 60, the separator 60 not only achieves electrical isolation but also participates in the arc-extinguishing process, enhancing the overall arc-extinguishing capability and operational safety of the knife-type contact fuse.

[0042] The silver-clad copper composite material combines the excellent conductivity of copper with the oxidation resistance of silver. It provides a low-resistance current path during fuse operation while effectively suppressing oxidation caused by high temperatures or prolonged current carrying, thus maintaining the stable conductivity of the fuse section 50 and improving the fuse's service life and reliability. The outer surface of the fuse section 50 is coated with an anti-oxidation coating. This coating further prevents corrosion of the fuse section 50 material by oxygen or moisture in the air, reducing surface oxidation and blackening, and improving the long-term stability of the fuse section 50 in high-temperature and high-humidity environments. Simultaneously, the anti-oxidation coating also reduces potential localized overheating during arc extinction, ensuring higher safety and reliability of the fuse in actual operation.

[0043] Preferably, the thermally conductive layer is a graphene thermally conductive coating or a copper plate thermally conductive layer with an insulating layer on its surface. The graphene thermally conductive coating has extremely high thermal conductivity, which can quickly conduct the heat generated by the fuse element to the outside of the housing 10 during fuse operation, thereby effectively reducing the temperature rise rate inside the cavity and improving the thermal stability of the device. On the other hand, the copper plate thermally conductive layer with an insulating layer on its surface maintains high thermal conductivity while also providing good electrical insulation performance, preventing short circuits between the thermally conductive layer and the housing 10 or the fuse segment 50, thereby ensuring the safe operation of the fuse under high current and high voltage conditions. The thermally conductive layer is connected to the sidewall of the cavity by adhesive or clips. Fixing the thermally conductive layer by adhesive or clips not only ensures close contact between the thermally conductive layer and the sidewall of the cavity, improving heat conduction efficiency, but also reduces the risk of displacement of the thermally conductive layer due to thermal expansion or vibration during long-term use, enhancing the overall stability and reliability of the structure.

[0044] This invention provides a method for manufacturing a knife-type contact fuse. The knife-type contact fuse comprises a housing 10, a fusible element, and an active heat dissipation structure 30. The housing 10 utilizes aluminum nitride ceramic powder, graphene sheets, multi-walled carbon nanotubes, silicon-carbon alloy powder, zirconium oxide or alumina nanoparticles, interfacial coupling agents, and dispersants. This allows the housing 10 to maintain good insulation and mechanical strength while possessing excellent thermal conductivity. This facilitates the rapid conduction and dispersion of heat generated by the fusible element during current carrying and fusing, reducing localized temperature rise within the housing 10, delaying material thermal aging, and thus extending the fuse's service life. Simultaneously, a thermally conductive layer is provided on the inner wall of the housing 10, and thermally conductive silicone grease is filled between the thermally conductive layer and the inner wall, forming a continuous, low-thermal-resistance heat transfer path. This allows the heat generated by the fusible element to be transferred more efficiently to the outside of the housing 10, further improving overall heat dissipation efficiency and preventing drift in fusing characteristics or degradation of insulation performance due to heat accumulation. The active heat dissipation structure 30, which is detachable on the outside of the housing 10, is used to reliably fix the heat dissipation fins 32 to the outer wall of the housing 10 via magnetic attraction. This not only increases the heat exchange area but also achieves efficient heat dissipation without changing the fuse body structure, which is beneficial for flexibly configuring heat dissipation capacity under different application conditions. In addition, by setting a separator 60 between multiple parallel fuse segments 50 and arranging a multi-layer metal grid arc extinguishing structure 70 on the side of the separator 60 facing the fuse segment 50, the present application can effectively divide, elongate and cool the generated arc at the moment of melting, significantly suppressing arc propagation and thermal coupling and arc crosstalk between adjacent fuse segments 50, and improving the consistency and safety of the melting response. The narrow neck region 51 set in the middle of each fuse segment 50 makes the melting position controllable, which helps to achieve fast and stable melting action. Therefore, the knife-type contact fuse prepared by the method of the present invention has excellent performance in terms of heat dissipation capacity, melting reliability and safety under high current and high load conditions.

[0045] The above-disclosed embodiments are merely some preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for manufacturing a knife-type contact fuse, characterized in that: The knife-type contact fuse includes a housing, a fusible element unit, and an active heat dissipation structure. The housing has annular metal rings on its four outer walls. A cavity is provided inside the housing, and a thermally conductive layer is provided on the sidewall of the cavity. Thermally conductive silicone grease is applied between the thermally conductive layer and the sidewall of the cavity. The fusible element unit is housed within the cavity and includes multiple parallel-connected fusing segments. Each fusing segment has at least one narrow neck region formed by cross-sectional area contraction. A knife-type contact is connected to each end of the parallel-connected fusing segments. A separator is provided between each fusing segment, and an arc-extinguishing structure, comprising a multi-layered metal grid, is provided on the side of each separator facing the fusing segment. The active heat dissipation structure includes a connecting base and multiple heat dissipation fins perpendicular to the connecting base. An annular magnetic element is provided on the connecting base and magnetically connected to the annular metal rings. The manufacturing method of the knife-type contact fuse includes the following steps: (1) Preparation of composite material slurry for making shell: Mix the following components by mass percentage to prepare a material mixture for making shell: aluminum nitride ceramic powder: 30% to 45%; thermosetting high temperature resin: 35% to 50%; graphene sheets: 0.5% to 1.5%; multi-walled carbon nanotubes: 0.3% to 1.2%; silicon-carbon alloy powder: 3% to 10%; zirconium oxide or alumina nanoparticles: 2% to 6%; interfacial coupling agent and dispersant: 0.1% to 2%; the mixture is mixed under high shear to form a composite material slurry suitable for injection molding or hot pressing. (2) Molded shell: The shell is prepared by injection molding or hot pressing of the composite material slurry. The shell is a hollow structure and has a metal ring embedded in its four outer walls. (3) Setting a heat-conducting structure: A heat-conducting layer is set on the side wall surface of the inner cavity of the housing. The heat-conducting layer is installed to the cavity of the housing by dispensing or snapping, and thermal grease is filled between it and the side wall of the cavity. (4) Assemble the melt unit and the partition structure: The melt unit is fitted with each melt segment on the partition, which is composed of a partition plate and a connecting plate. The partition plate is provided with a grid-type arc extinguishing structure composed of multiple metal sheets between each pair of melt segments. Then the melt unit and the partition are installed into the cavity of the shell. The melt unit includes multiple melt segments arranged in parallel. Each melt segment has a narrow neck area in the middle. (5) Install the active heat dissipation structure: The active heat dissipation structure is installed on the outer wall of the shell. The active heat dissipation structure includes a connecting base and multiple vertically arranged high thermal conductivity heat dissipation fins. The connecting base is provided with an annular magnetic attractor, which is magnetically connected to the metal ring on the outer wall of the shell.

2. The method for manufacturing the knife-type contact fuse as described in claim 1, characterized in that, The thermosetting high-temperature resin is a modified phenolic resin or an epoxy resin with heat resistance, and its glass transition temperature is not lower than 180°C.

3. The method for manufacturing a knife-type contact fuse as described in claim 2, characterized in that, The shell is formed using a vacuum-assisted hot pressing process.

4. The method for manufacturing the knife-type contact fuse as described in claim 1, characterized in that, The separator includes multiple partitions and a connecting plate connected between the partitions. The top of the connecting plate is recessed to the bottom side and a limiting groove is provided. The fusible segment is engaged in the limiting groove. The partition is provided with the arc extinguishing structure.

5. The method for manufacturing a knife-type contact fuse as described in claim 1, characterized in that, The width of the partition is equal to or slightly smaller than the gap between the sidewalls of the cavity.

6. The method for manufacturing the knife-type contact fuse according to claim 1, characterized in that, In the arc-extinguishing structure, there are gaps between each layer of the multi-layered metal sheet grid, and the metal sheets are staggered in the longitudinal direction.

7. The method for manufacturing a knife-type contact fuse as described in claim 1, characterized in that, The metal grid of the arc-extinguishing structure is made of stainless steel, and its surface is provided with an oxide layer to enhance its high-temperature resistance and insulation performance.

8. The method for manufacturing a knife-type contact fuse as described in claim 1, characterized in that, The separator is a ceramic insulating separator, and it has multiple raised, diffused arc tooth structures on the side facing the fused section.

9. The method for manufacturing a knife-type contact fuse as described in claim 1, characterized in that, The fused section is made of silver-coated copper composite material and is covered with an anti-oxidation coating.

10. The method for manufacturing a knife-type contact fuse as described in claim 1, characterized in that, The thermally conductive layer is a graphene thermally conductive coating or a copper plate thermally conductive layer with an insulating layer on its surface. The thermally conductive layer is connected to the side wall of the cavity by adhesive or clips.

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