Excitation fuse with melt structure

Abstract

An excitation fuse with a melt structure comprises a shell, an excitation source, at least one conducting bar and the melt structure. A first cavity and a second cavity filled with an arc extinguishing medium are arranged in the shell; the cavity where the driving force releasing end of the excitation source is located is communicated with the first cavity, and the conducting bar penetrates through the shell and the first cavity; the melt structure is arranged at least partially in the arc extinguishing medium in the second cavity or penetrates through the arc extinguishing medium in the second cavity; the fuse body structure comprises a fuse body connected with the conducting bar in parallel and insulation isolation pieces, at least one insulation isolation piece is arranged on the fuse body in the current direction, the fuse body penetrates through the insulation isolation pieces, and the insulation isolation pieces are used for partially or completely isolating electric arcs at fractures of the fuse body and releasing gas and cooling the electric arcs at the high temperature of the electric arcs. The excitation fuse uses a melt structure, so that the breaking performance of the fuse and the insulating performance and the voltage resistance after breaking can be improved.

Description

Technical Field

[0001] The invention relates to the field of circuit protection, and particularly to a fuse structure used in the field of circuit protection, and in particular to an excitation fuse provided with the fuse structure. Background Art

[0002] An excitation fuse generally includes an excitation source, a piston, a conductive bar, and an arc-extinguishing fuse. The excitation source releases a driving force based on the received trigger signal, driving the piston to move. The piston breaks the conductive bar, thereby disconnecting the circuit and achieving circuit protection. In order to improve the breaking capacity and arc extinguishing capacity, an arc-extinguishing fuse is connected in parallel to the conductive bar. The resistance value of the arc-extinguishing fuse is much greater than the resistance value of the conductive bar. During normal current flow, most of the current flows through the conductive bar, and the current flowing through the arc-extinguishing fuse is negligible. When the conductive bar is disconnected, the current flows through the arc-extinguishing fuse, and the arc-extinguishing fuse melts or is disconnected mechanically. After the fuse is disconnected, the arc-extinguishing medium participates in extinguishing the arc. When the arc-extinguishing fuse is disconnected, arcing or breakdown is likely to occur at the fracture, making it difficult to establish good insulation after the arc-extinguishing fuse is disconnected.

[0003] When the melt of the thermal fuse and the arc-extinguishing melt of the excitation fuse are both melted through thermal melting, the melt and the narrow diameter of the melt melt or vaporize, forming a fracture after melting, which is actually a small explosion under overall safety control, and the conductive bar diffuses and ceramicizes; because the physical fracture insulation cannot be effectively established, after disconnection, the metal ion diffusion at the fuse fracture is relatively random, resulting in unstable or poor insulation performance after disconnection; because the insulation at the fracture is poor or unstable, under high voltage, it is easy to have a large leakage current, breakdown and the risk of disconnection failure (explosion, etc.).

[0004] For example, existing excitation fuses include an excitation source, a piston, at least one conductive bar, a first cavity, and a second cavity. The excitation source and piston are disposed in the first cavity, the conductive bar is disposed within the housing and passes through the first cavity, and the piston is disposed in correspondence with the conductive bar. The fuse, connected in parallel to the conductive bar, is disposed in a second cavity filled with an arc-extinguishing medium. Because the second cavity utilizes the housing space outside the first cavity, it is relatively narrow and small. After the fuse disconnects, arcing is easily generated at the fracture formed in the fuse, which can lead to arcing or arc breakdown. Effective physical insulation cannot be established at the fractured fuse, resulting in poor insulation performance. These drawbacks are more severe than those of conventional excitation fuses. Summary of the Invention

[0005] The purpose of the present invention is to provide an excitation fuse with a melt structure. By changing the melt structure, an insulating spacer is set on the melt, and a plurality of chambers are established in the arc extinguishing chamber through the insulating spacer. The cooling arc is isolated by the insulating spacer, thereby improving the post-break insulation performance and breaking capacity of the excitation fuse.

[0006] To achieve the above object, the present invention provides an excitation fuse with a melt structure, comprising a housing, an excitation source, at least one conductive bar, and a melt structure;

[0007] A first cavity and a second cavity filled with an arc-extinguishing medium are provided in the housing; a chamber where a driving force release end of the excitation source is located is communicated with the first cavity, and the conductive bar passes through the housing and the first cavity; the melt structure is at least partially located in / or passes through the arc-extinguishing medium in the second cavity;

[0008] The melt structure includes a melt and an insulating spacer; the melt passes through the arc-extinguishing medium in the second cavity, and the two ends of the melt are conductively connected to the conductive bar in parallel. At least one insulating spacer is arranged between the two ends of the current direction of the melt, and the melt passes through the insulating spacer. The insulating spacer is arranged in the arc-extinguishing medium in the second cavity. The insulating spacer is used to partially or completely isolate the arc at the fuse break and release gas at the high temperature of the arc to cool the arc; when the excitation source is activated according to the received trigger signal and releases the driving force, the driving force acts on the conductive bar to disconnect the conductive bar, and then the melt is melted.

[0009] Preferably, the insulating spacer and the melt are gap-fitted or sealed.

[0010] Preferably, when the sealing connection is made, the insulating spacer and the melt are integrally injection-molded, or the gap between the insulating spacer and the melt is sealed by a sealant.

[0011] Preferably, the insulating spacer is provided with a notch or a through hole for the melt to pass through, and the melt passes through the notch or the through hole.

[0012] Preferably, the gap between the melt and the notch or through hole is filled with the sealant.

[0013] Preferably, the cross-sectional shape of the insulating spacer includes: at least one angular shape, or at least partially an arc shape.

[0014] Preferably, the cross-sectional shape of the insulating spacer includes at least one of the following shapes: square, circle, diamond, and trapezoid.

[0015] Preferably, a groove is provided on the surface of at least one side of the insulating spacer along the direction of the melt current.

[0016] Preferably, the insulating spacer is made of an insulating, high-temperature resistant and flame-retardant material.

[0017] Preferably, the insulating spacer is made of at least one of the following materials: rubber, ceramics, and engineering plastics; when ceramic material is used, a gas-generating substance capable of releasing gas at high temperature is provided on the ceramic material.

[0018] Preferably, a narrow neck of at least one specification is provided between the two ends of the melt, and the heat dissipation section is provided at the maximum width on one side or both sides of the narrow neck in the current direction; at least one insulating spacer is provided at the narrow neck or the heat dissipation section.

[0019] Preferably, when the narrow neck is provided with one specification, the melt includes an arc extinguishing section and a heat dissipation section, and the narrow neck is the arc extinguishing section; when the narrow neck is provided with two or more specifications, the melt includes an arc starting section, an arc extinguishing section and a heat dissipation section, the narrow neck that arcs and melts first is the arc starting section, and the narrow neck that arcs and melts later is the arc extinguishing section; at least one insulating isolation piece is provided at the arc starting section or the arc extinguishing section.

[0020] Preferably, the insulating spacer is arranged at the arc striking section.

[0021] Preferably, the shape of the insulating spacer matches the shape of the second cavity, and the insulating spacer isolates the second cavity into a plurality of independent chambers that are not connected to each other.

[0022] Preferably, the insulating spacer is in sealing contact with the second cavity, and the insulating spacer is used to isolate the second cavity into a plurality of independent chambers that are not connected to each other.

[0023] Preferably, the driving force released by the excitation source is high-pressure gas.

[0024] Preferably, it further comprises a piston located in the first cavity, and the piston is arranged corresponding to the conductive bar.

[0025] Preferably, the conductive bar includes at least two insulated conductive bars; the impact ends of the piston are respectively arranged corresponding to the conductive bars; the melt structure is connected in parallel to at least one of the conductive bars, and the melt structure is located in the second cavity.

[0026] Preferably, when there are two or more conductive bars, the conductive bars are arranged side by side, staggered in layers, or staggered in positions.

[0027] Preferably, a thermal cutoff is provided in the second cavity, and the melt structure is provided in the thermal cutoff.

[0028] Preferably, the second cavity is located outside the piston displacement path or in front of the piston displacement path.

[0029] The excitation fuse of the present invention uses a melt structure in a smaller arc extinguishing chamber, and isolates the arc extinguishing chamber into several chambers through insulating isolators, which are used to isolate the arc generated after the melt is disconnected to prevent arc breakdown; the insulating isolators effectively make the arc close to the insulating isolators thinner, and effectively limit the shape and size of the arc. At the same time, the high temperature generated by the arc is used to vaporize the insulating tube isolator, releasing a large amount of gas, and the metal ions close to the insulating tube isolator are blown away by the gas, forming effective arc isolation and insulation, which fully improves the insulation and voltage resistance performance of the arc extinguishing chamber after the melt is melted; thereby improving the overall breaking performance of the excitation fuse and the insulation performance and voltage resistance performance after breaking, effectively ensuring the reliability and stability of the excitation fuse breaking; and improving the flexibility and adjustment range of the fuse melt scheme design. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a three-dimensional structural diagram of the melt structure.

[0031] Figure 2 It is a schematic diagram of the front view of the melt structure.

[0032] Figure 3 It is a schematic diagram of the melt structure from a top view.

[0033] Figure 4 It is a structural schematic diagram of an insulating spacer provided with a groove.

[0034] Figure 5 It is a structural schematic diagram of an insulating spacer provided with through holes.

[0035] Figure 6 It is a schematic diagram of a melt having a narrow neck of a certain specification.

[0036] Figure 7 It is a schematic diagram of a melt having two specifications of narrow necks.

[0037] Figure 8 It is a schematic diagram of the principle structure of setting the fuse structure in the excitation fuse.

[0038] Figure 9 This is the appearance structure diagram of the compact excitation fuse.

[0039] Figure 10 It is a three-dimensional cross-sectional structural diagram of a compact excitation fuse provided with a melt structure.

[0040] Figure 11 It is a schematic diagram of the cross-sectional structure of the second cavity provided with the melt structure.

[0041] Figure 12 This is a schematic diagram of the appearance of a second cavity arranged at the bottom of the excitation fuse.

[0042] Figure 13 yes Figure 12 A three-dimensional cross-sectional view of .

[0043] Figure 14 yes Figure 12 Schematic diagram of the second cavity structure provided with a melt structure.

[0044] Reference numerals

[0045] Melt 1, insulating spacer 2, heat dissipation section 3, notch structure 4, through hole 5, narrow neck 6, first narrow neck 7, second narrow neck 8, sealing ring 20, upper shell 21, middle shell 22, lower shell 23, excitation source 24, piston 25, first conductive bar 26, arc extinguishing medium 27, second conductive bar 28, screw 29, sealant 30, thermal melt fuse 31, fuse housing 32, and upper cover 33. DETAILED DESCRIPTION

[0046] The excitation fuse with a melt structure of the present invention comprises a housing, an excitation source, at least one conductive bar, and a melt structure;

[0047] A first cavity and a second cavity filled with an arc-extinguishing medium are provided in the housing; a chamber where a driving force release end of the excitation source is located is communicated with the first cavity, and a conductive bar passes through the housing and the first cavity; a melt structure is at least partially located in / or passes through the arc-extinguishing medium in the second cavity;

[0048] The melt structure includes a melt and an insulating isolator; the melt passes through the arc-extinguishing medium in the second cavity, and the two ends of the melt are conductively connected to the conductive bar in parallel. At least one insulating isolator is arranged between the two ends of the current direction of the melt. The melt passes through the insulating isolator, and the insulating isolator is arranged in the arc-extinguishing medium in the second cavity. The insulating isolator is used to partially or completely isolate the arc at the fuse break, and release gas at the high temperature of the arc to cool the arc; when the excitation source is activated according to the received trigger signal, the driving force is released, and the driving force acts on the conductive bar to disconnect the conductive bar, and the melt is melted.

[0049] The excitation fuse of the present invention adds a melt structure to the arc extinguishing chamber of the excitation fuse. The arc extinguishing chamber is separated into several chambers by insulating spacers provided on the melt structure. When an arc is generated, the insulating spacers can actively extinguish the arc. The active arc extinguishing method and working mode are as follows:

[0050] The insulating spacer itself is made of an insulating material, at least partially isolating the melt on either side of the insulating spacer and the arc generated by the melt blowing, thereby improving insulation and breaking performance. When there is no gap between the insulating spacer and the arc extinguishing chamber, the melt on either side of the insulating spacer is completely isolated, and the arc generated by the melt blowing on both sides of the insulating spacer is completely isolated, further improving insulation and breaking performance.

[0051] When there is a gap between the insulating isolation piece and the second cavity, the insulating isolation piece expands and contracts under high temperature, allowing the power arc to pass through the gap between the insulating isolation piece and the arc extinguishing chamber, further isolating the arc. Moreover, when the insulating isolation piece has appropriate hardness, the effect of isolating the arc is better.

[0052] The insulating spacer is partially or completely vaporized under the action of the high-temperature arc, blowing the arc, which is conducive to extinguishing the arc and further improving the breaking performance.

[0053] The preferred embodiments are described below in detail with reference to the accompanying drawings. The directional words involved are based only on the directions shown in the accompanying drawings and do not constitute a limitation on the technical solution of the present invention.

[0054] Melt structure, see Figures 1 to 3 The device comprises a melt 1, an insulating spacer 2, and a heat sink 3. The melt 1 is a long, sheet-like structure made of a conductive material. Several heat sinks 3 are spaced along the direction of current flow (i.e., the length) of the melt 1. Heat sinks 3 have the largest cross-sectional area and therefore the largest heat dissipation area. Heat sinks 3 can quickly transfer heat generated by the melt to the outside of the melt, thereby reducing the melt temperature.

[0055] Insulation spacers 2, a plurality of insulation spacers 2 are arranged on the melt 1 in the direction of current flow, see Figures 1 to 3, the insulating isolator 2 is arranged between the heat dissipation sections adjacent to each other in the direction of current flow. The maximum outer diameter of the insulating isolator 2 is greater than the maximum width of the melt structure, that is, greater than the width of the heat dissipation section, and the melt 1 is supported and arc isolated by the insulating isolator 2. The material of the insulating isolator 2 is an insulating, high-temperature resistant flame-retardant material. It can include at least one of insulating, high-temperature resistant flame-retardant materials such as rubber, ceramics, and engineering plastics. In a preferred embodiment, the insulating isolator is made of an insulating material that can produce and release gas at high arc temperatures, preferably, such as silicone rubber; when it is a ceramic material, it is used in combination with other materials, for example, the gap between the melt and the ceramic is filled with rubber or engineering plastics. The ratio of the thickness of the insulating isolator in the direction of current flow to the length of the melt is in the range of 1:1000 to 1:5. The thickness of the insulating spacer is 0.5 to 20 mm, preferably 0.5 to 3.5 mm. More preferably, the thickness of the insulating spacer is 1.0 to 2.0 mm, and the specific thickness can be designed to be 1.0 mm or 1.5 mm. The Shore hardness ranges from 30 to 90 HA, preferably 60 to 90 HA, and the specific Shore hardness can be designed to be 60 HA, 70 HA, 80 HA, or 90 HA. Within the Shore hardness range, the higher the hardness, the better the effect, and the higher the hardness, the easier it is to process.

[0056] The cross-sectional shape of the insulating spacer 2 includes: at least one angular shape, or at least a partially arcuate shape, such as at least one of a square, a circle, a diamond or a trapezoid. Figure 4 In one embodiment, the cross-sectional shape of the insulating isolator 2 can be square. In order to facilitate the assembly of the insulating isolator 2 and the melt, a notch structure 4 for the melt 1 to pass through is provided on the insulating isolator 2. The notch structure 4 passes through the thickness of the insulating isolator 2, that is, on both sides of the current direction. Grooves are respectively provided on the two side surfaces of the square insulating isolator 2 in the current direction. When the grooves are provided, the insulating isolator 2 is thin in the middle and thick at the edges, which is convenient for assembly and operation, and improves the operability of the process; at the same time, the strength of the insulating isolator 2 is improved without increasing the thickness of the position where the melt passes through. During assembly, the melt 1 is passed through the notch structure 4, and then the gap between the melt 1 and the notch structure 4 is filled with sealant, and the melt 1 is fixed to the notch structure 4 of the insulating isolator 2 by the sealant. Preferably, the sealant can be 703 silicone and 5088 glue.

[0057] See Figure 5Taking a preferred embodiment as an example, the insulating spacer 2 may be a circular structure with a through-hole 5 provided at the center thereof for the melt 1 to pass through. Grooves are provided on both sides of the insulating spacer 2 in the direction of current flow. The melt 1 passes through the through-hole 5 and is disposed on the insulating spacer 2, with the insulating spacer 2 providing support for the melt 1. A clearance fit may be provided between the melt 1 and the through-hole 5, or a sealant may be filled in the clearance. When the melt 1 and the insulating spacer 5 are clearance-fitted, the clearance is sufficient to prevent an arc from passing through.

[0058] The melt 1 and the insulating spacer 2 can be independent components that are then assembled together, or they can be integrally formed by embedded mold injection molding.

[0059] Depend on Figure 4 and Figure 5 It can be seen that the melt 1 passes through the insulating isolation piece 2, and the periphery of the position where the melt 1 passes through the insulating isolation piece is completely covered by the insulating isolation piece 2, or is completely covered by the insulating isolation piece 2 and the sealant, forming a complete isolation of the arc at the melt fracture.

[0060] In some embodiments, at least a portion of the melt 1 in the width direction can be surrounded by the insulating isolation member 2, so that the insulating isolation member 2 supports the melt 1, partially isolates the melt portions on both sides of the insulating isolation member 2, and partially isolates the arc generated at the melt fracture.

[0061] Preferably, the insulating isolation piece 2 covers the periphery of the melt 1, and the insulating isolation piece 2 and the melt 1 are in sealed contact, thereby improving the complete insulation isolation performance of the melt part and the arc at the port on both sides of the insulating isolation piece 2. At the same time, it forms the most reliable support for the melt 1 without the need for additional supporting elements.

[0062] Grooves may be provided on both sides of the insulating spacer 2 in the current direction, or on only one side. In some embodiments, no grooves may be provided.

[0063] At least one specification of narrow neck 6 is provided on the melt 1 in the current direction. The specification of the narrow neck here refers to the width and shape of the narrow neck, one specification means that the width and shape of the narrow neck are the same, and two specifications of narrow necks mean that the width and shape of the narrow neck are different.

[0064] See Figures 1 to 2 The narrowest section of the melt 1 is the narrow neck 6, and the widest section of the melt is the heat dissipation section 3, which is located on one side or both sides of the narrow neck 6. Figure 1 and Figure 2In the embodiment, the narrowest part of the melt 1 is divided into several sections, that is, several narrow necks 6 are provided on the melt 1, and each narrow neck 6 has the same width and shape, that is, several narrow necks 6 of the same specifications are provided on the melt 1. When the melt is melted, since the width of the narrow neck 6 is the narrowest and the resistance is the largest, the temperature of the narrow neck 6 rises fastest, and the temperature of the narrow neck 6 first rises to the melting point of the melt 1. The melt 1 starts to arc and melts at the narrow neck 6. Since the narrow necks 6 are all of the same specifications, there may be many narrow necks where the melt 1 melts. Figure 1 and Figure 2 All narrow necks 6 of the same specification are defined as the arc extinguishing section. As the narrow neck 6 heats up and melts, most of the heat energy at the narrow neck 6 is conducted along the length of the melt toward the heat dissipation section 3. Because the heat dissipation section 3 is wide and has a large heat dissipation area, the heat dissipation effect through the heat dissipation section 3 is better than that at the narrow neck 6. Figure 1 and Figure 2 In the embodiment, the insulating spacer 2 is arranged at the narrow neck 6, that is, at the arc extinguishing section.

[0065] See Figure 6 Several narrow necks 6 of the same specification are provided on the melt 1 in the direction of current flow. The width of the narrow necks 6 is the width of the melt through which current flows. The width of the narrow necks 6 (i.e., the actual width of the melt flowing through the narrow necks, excluding the width of the through-holes in the narrow necks) is smaller than the width of the melt on one side of the narrow necks 6 (the actual width of the melt flowing through). Therefore, the narrow necks 6 of the same specification all serve as arc extinguishing sections. The section with the largest melt width on one or both sides of the narrow necks 6 serves as the heat dissipation section 3.

[0066] See Figure 7 Two sizes of narrow necks are spaced apart on the fuse 1 in the direction of current flow. The narrow neck with the smallest flow width is the first narrow neck 7, and the narrow neck with a flow width greater than the first narrow neck 7 is the second narrow neck 8. The melt portion with the largest actual flow width, located on one or both sides of the narrow neck, is the heat dissipation section 3. The actual flow width of the first narrow neck 7 is smaller than that of the second narrow neck 8. That is, the resistance at the first narrow neck 7 is greater than that at the second narrow neck 8. Therefore, when the fuse blows, the temperature rises faster at the first narrow neck 7 than at the second narrow neck 8. The temperature at the first narrow neck 7 reaches the melting point of the melt first, and the temperature at the second narrow neck 8 reaches the melting point later. The first narrow neck 7 arcs and blows first, and the second narrow neck 8 arcs and blows later. Therefore, the first narrow neck 7, which arcs and blows first, is defined as the arcing section, and the second narrow neck 8, which arcs and blows later, is defined as the arcing section.

[0067] As can be seen from the above, as long as a narrow neck is provided on the melt 1, the melt 1 must include an arc extinguishing section and a heat dissipation section. When a narrow neck of one specification is provided on the melt, the melt 1 includes an arc extinguishing section and a heat dissipation section; when a narrow neck of two or more specifications is provided on the melt 1, the melt 1 includes an arc starting section, an arc extinguishing section, and a heat dissipation section.

[0068] The insulating spacer 2 can be set on any of the arc starting section, arc extinguishing section and heat dissipation section on the melt 1, and is suitable for application requirements under different arc extinguishing and insulation performance. The insulating spacer is preferably set in the arc starting section or the arc extinguishing section, that is, set at the narrow neck. When there are only arc extinguishing sections and heat dissipation sections in the melt, the insulating spacer is preferably set in the arc extinguishing section. This makes the insulation performance of the melt better after breaking and the arc duration shorter. When the insulating spacer is set in the arc starting section, it can improve the insulation performance after breaking and reduce the arc energy during the breaking process. In some embodiments, at least one isolating insulator is set at the arc starting section.

[0069] The actual flow width of the melt 1 through the narrow neck 6 adjusts the melt melting rate. The smaller the actual flow width, the greater the melting rate.

[0070] The above-mentioned fuse structure can be integrated into a circuit protection device for protecting an external circuit. When the circuit protection device is used for external circuit protection, the integrated fuse structure is connected in series or in parallel with the external circuit. For example, when the circuit protection device is a thermal melt fuse, the fuse structure serves as the fuse of the thermal melt fuse and is connected in series with the external circuit. When the fuse structure blows, the external circuit is disconnected. When the circuit protection device is an excitation fuse, the fuse structure is connected in parallel to the conductor of the excitation fuse, and the conductor is connected in series with the external circuit. Then, the fuse structure is connected in parallel with the external circuit. When the conductor of the excitation fuse is disconnected, the fuse structure blows or is disconnected mechanically, completely disconnecting the external circuit and achieving protection for the external circuit. The following describes the structure of the thermal melt fuse and the excitation fuse using the above-mentioned fuse structure.

[0071] For the energized fuse using the above mentioned fuse structure, see Figure 8 , including a shell, an excitation source 24, a piston 25, a first conductive bar 26, an arc extinguishing medium 27, and a melt structure. In this embodiment, the shell is spliced ​​together by an upper shell 21, a middle shell 22, and a lower shell 23. The structure of the shell is not limited to a structure spliced ​​together by the upper shell 21, the middle shell 22, and the lower shell 23. It can also be spliced ​​left and right, or it can be spliced ​​together by two or even more shell parts, and a first cavity and a second cavity are provided in the shell. The excitation source 24 and the piston 25 are arranged in the first cavity, and the first conductive bar 26 is passed through. The resistance value of the melt 1 of the melt structure is much greater than the resistance value of the first conductive bar 26. Under normal working conditions, the current flows through the first conductive bar 26, and the current flowing through the melt 1 can be ignored.

[0072] The excitation source 24 can be activated according to the received trigger signal and release a driving force as the power to interrupt the conductive bar. The driving force released by the excitation source 24 can be high-pressure gas, high-pressure fluid, mechanical force such as torque, etc.

[0073] The excitation source 24 and the piston 25 are respectively arranged in the first cavity in the upper shell 21. The excitation source 24 closes the top open end of the upper shell 21, and the end of the excitation source 24 that releases the driving force is arranged toward the piston 25. A sealing ring 20 is provided at the contact surface between the piston 25 and the inner wall of the upper shell 21 to seal the contact surface between the piston 25 and the upper shell 21. The cavity where the end of the excitation source 24 that releases the driving force is located is connected to the cavity where the end of the piston away from the first conductive bar 26 is located. The first conductive bar 26 is arranged between the upper shell 21 and the middle shell 22 and passes through the first cavity. The piston 25 is located between the excitation source 24 and the first conductive bar 26. A pre-break is provided on the first conductive bar 26 located in the first cavity to break the weak point, and the piston 25 is arranged corresponding to the pre-break of the first conductive bar 26.

[0074] A second cavity is provided in the lower shell 23 as an arc extinguishing chamber. Figure 8 In the embodiment, the second cavity is located below the first cavity, that is, in front of the piston displacement path. The second cavity is filled with an arc-extinguishing medium 27. The melt structure is arranged in the arc-extinguishing medium 27 of the second cavity, wherein: the melt 1 of the melt structure is arranged in the arc-extinguishing medium 27, and the two ends of the melt 1 pass through the second cavity and are conductively connected to the two outer sides of the current direction of the pre-break of the first conductive bar 26, so that the melt 1 is connected to the first conductive bar 26 in a parallel manner, so that the melt 1 forms a parallel relationship with the pre-break of the first conductive bar 26. The insulating spacer 2 is in sealed contact with the inner wall of the second cavity, and the insulating spacer 2 supports the melt 1. At the same time, the insulating spacer 2 isolates the second cavity into several independent and non-interconnected chambers. The sealed contact method can be a gapless fit contact, or it can be achieved by filling the contact gap with a sealant for sealing and fixing. Gapless contact can be achieved by matching the shape of the insulating spacer 2 with the shape of the second cavity. If the shape of the insulating spacer 2 does not match the shape of the second cavity, sealing can be achieved by filling a sealant between the insulating spacer 2 and the second cavity. The insulating spacer 2 isolates the second cavity into several independent chambers that are not connected to each other, completely isolating the melt on both sides of the insulating spacer 2 and completely isolating the arc on both sides of the insulating spacer.

[0075] Working principle:

[0076] During normal operation, current flows through the first conductive bar 26 . The resistance of the fuse 1 is much greater than the resistance of the conductive bar 26 , and the current flowing through the fuse 1 can be ignored.

[0077] When an abnormal situation occurs, that is, when overcurrent occurs, the excitation source 24 operates according to the received trigger signal, releasing high-pressure gas as a driving force, driving the piston 25 to displace, and the displaced piston 25 breaks the pre-break of the first conductive bar 26 to form a break on the first conductive bar 26. The current flows through the melt 1. When the melt 1 melts, an arc column is formed. Because the insulating isolation piece 2 acts as a retaining wall, the arc column will immediately become thinner because it has to pass through the insulating isolation piece 2. The size of the arc column is effectively limited. With the help of the good cooling effect of the insulating isolation piece 2, the arc temperature is reduced, the arc voltage is increased, and the current is reduced. At the same time, the insulating isolation piece 2 produces a large amount of gas at high temperature, and the molten metal ions around the insulating isolation piece 2 are blown away, forming effective arc isolation and insulation at this position, which fully improves the post-break insulation and voltage resistance performance of the product, while ensuring the reliability of the protection performance of the excitation fuse.

[0078] In some embodiments, a gap may exist between the insulating isolator 2 and the inner wall of the second cavity. The insulating isolator 2 isolates the second cavity into several chambers, and the chambers can only be connected through the gap. In this structure, the insulation isolation performance is relatively poor compared to the isolation effect of the insulating isolator 2 in sealed contact with the second cavity. Under the high temperature of the arc, the insulating isolator undergoes thermal expansion, which can reduce the gap. When the gap is small, the gap can even disappear. Therefore, after the melt in each chamber formed by the isolation melts, the arc generated is difficult to pass through the gap into another chamber, and arcing is difficult to occur. At the same time, the insulating isolator plays a role in refining and cooling the generated arc, and can also prevent arc breakdown. Therefore, even if there is a gap between the insulating isolator 2 and the second cavity, it can still improve the insulation performance after the melt breaks.

[0079] Figure 8 In the excitation fuse, the second cavity where the arc-extinguishing melt is located is arranged in front of the piston in the displacement direction, which increases the volume in the excitation fuse housing, making the excitation fuse relatively large in volume and weight.

[0080] In order to make the structure of the excitation fuse more compact and make full use of the space of the existing shell of the excitation fuse, the arc extinguishing chamber is arranged in the shell outside the piston displacement path, making full use of the unused space in the existing shell, thereby improving space utilization.

[0081] Excitation fuse, see Figures 9 to 11, comprising a housing, an excitation source 24, a piston 25, a first conductive bar 26, an arc-extinguishing medium 27, and a second conductive bar 28. The housing is composed of an upper shell 21, a middle shell 22, and a lower shell 23, which are fixed together by screws 29. The housing comprises a first cavity for piston displacement and at least one second cavity located outside the first cavity in the direction of piston displacement. The excitation source 24 is disposed in the first cavity portion of the upper shell 21, and the contact portion between the excitation source 24 and the first cavity is sealed. The piston 25 is disposed in the first cavity portion of the middle shell 22, and the piston 25 is in sealed contact with the inner wall of the first cavity. To achieve this sealed contact, a sealing ring is provided on the outer circumference of the piston 25 to seal the contact surface between the piston 25 and the first cavity. A limit block is provided on the outer circumference of the end of the piston 25 facing the excitation source 24. The limit block is located between the contact surface of the upper shell 21 and the middle shell 22, defining the initial position of the piston 25. When piston 25 is displaced, it disconnects from the stopper, releasing the initial position of piston 25, and allows piston 25 to displace along the first cavity. First conductive bar 26 and second conductive bar 28 are insulated and spaced apart and arranged side by side between middle shell 22 and lower shell 23, with first conductive bar 26 and second conductive bar 28 extending through the first cavity. The piston 25 has impact tips corresponding to first conductive bar 26 and second conductive bar 28 on one end facing the conductive bars. The distances between the impact tips of piston 25 corresponding to first conductive bar 26 and second conductive bar 28 and the first conductive bar 26 and second conductive bar 28 can be the same or different. When the distances are the same, the impact tips of piston 25 simultaneously disconnect first conductive bar 26 and second conductive bar 28. When the distances are different, the impact tips of piston 25 disconnect first conductive bar 26 and second conductive bar 28 sequentially.

[0082] The second cavity is disposed within the middle shell 22, outside the first cavity, that is, outside the first cavity in the direction of piston displacement. Two arcuate grooves are defined on the end surface of the middle shell 22 facing the upper shell 21, on opposite sides of the first cavity. The upper shell 21 abuts against the middle shell 22, enclosing the two arcuate grooves of the middle shell 22 to form two arcuate second cavities. A melt structure is disposed in each of the two arcuate second cavities. The second cavities are filled with an arc-extinguishing medium, and the melt structure is disposed within the arc-extinguishing medium. A first conductive bar 26 and a second conductive bar 28 are connected in parallel to the melt 1 of the melt structure in one of the second cavities. The melt structure disposed in the second cavity includes the melt 1 and an insulating spacer 2. The insulating spacer 2 is in sealing contact with the inner wall of the second cavity, insulating and isolating the second cavity into a plurality of independent, non-interconnected chambers. The gap between the insulating spacer 2 and the inner wall of the second cavity is filled with sealant 30 to achieve a sealed contact. The sealant is preferably 703 or 5088. The fuse 1 is preferably disposed in the center of the second cavity. With this structure, when the fuse blows, the arc can only exist within a certain range due to the insulating isolation function of the insulating spacer. When the arc is about to pass through the insulating spacer 2, the insulating spacer 2 weakens and cools the arc. At the same time, the insulating spacer 2 releases gas under the high temperature of the arc, and the gas blows away the metal ions, forming effective arc isolation and insulation at this location, fully improving the product's post-break insulation and voltage resistance performance, while ensuring the reliability of the excitation fuse's protection performance.

[0083] The excitation fuse can be provided with one conductive bus, two conductive buses, three conductive buses, or even more conductive buses. When there are more than two conductive buses, the insulation spacing setting must be met first. In addition, multiple conductive buses can be arranged side by side, staggered in layers, or staggered in positions. When arranged side by side, the multiple conductive buses can be arranged on the same horizontal plane or on different horizontal planes. When staggered in positions, the multiple conductive buses can be staggered in positions with some of the conductive buses stacked up or down, or completely staggered in positions. When multiple conductive buses are staggered in layers or staggered in positions with some of the conductive buses stacked up or down, it is preferred that the pre-break position be staggered. This arrangement can make the excitation fuse relatively smaller.

[0084] One conductive busbar is connected to one circuit for circuit protection, and two conductive buses are connected to one circuit respectively. When used in a three-phase circuit, the two conductive buses are connected to one phase circuit respectively.

[0085] Working principle of excitation fuse:

[0086] Under normal working conditions, current flows through the first conductive bar 26 and the second conductive bar 208 . Since the resistance of the melt 1 is much greater than that of the first conductive bar 26 and the second conductive bar 208 , the current flowing through the melt 1 can be ignored.

[0087] When there is an overcurrent, the excitation source 24 operates according to the received trigger signal, releasing the driving force to drive the piston 25 to move and simultaneously cut off or successively cut off the first conductive bar 26 and the second conductive bar 28, forming fractures on the first conductive bar 26 and the second conductive bar 28 respectively. When the first conductive bar 26 and the second conductive bar 28 are disconnected, the current flowing through the first conductive bar 26 and the second conductive bar 28 flows through the melt 1 connected in parallel therewith, and the melt 1 is heated by the current flowing therethrough, causing the temperature to rise, and the melt 1 begins to melt and vaporize, and the melt is blown from the narrow neck; since an insulating spacer 2 is provided on the current transmission path of the melt 1, a sealant is filled in the gap between the insulating spacer 2 and the second cavity, the insulating spacer 2 and the sealant 30 block the hot air flow generated by the arc, isolating the arc from breaking; at the same time, with the help of the cooling effect of the insulating spacer 2, the arc around the insulating spacer 2 is quickly cooled down, effectively increasing the arc voltage and improving the arc extinguishing performance of the fuse; in addition, the insulating spacer 2 is easy to produce gas at high temperature, and the released gas blows away the molten metal ions around the insulating spacer 2, effectively establishing insulation on both sides of the current transmission of the insulating spacer 2, so that the fracture of the melt is completely physically insulated, thereby improving the post-break insulation performance and breaking reliability of the excitation fuse.

[0088] Figures 9 to 11 To excite the fuse structure used in the fuse, Figure 8 It is a conductive bar parallel to the melt structure, and the melt structure is arranged in front of the piston displacement path. Figures 8 to 11 The melt structure is directly placed in the second cavity. Alternatively, the melt structure can be first fabricated into a thermal cutoff and then placed directly in the second cavity. Alternatively, the thermal cutoff can be directly placed under the housing of the excitation fuse and then connected in parallel to the conductive bar of the excitation fuse. This structure can save multiple assembly steps and improve assembly efficiency.

[0089] See Figures 12 to 14The first conductive bar 26 and the second conductive bar 28 are insulated and spaced apart, arranged side by side and at different levels. That is, there is a height difference between the first conductive bar 26 and the second conductive bar 28. The two impact ends of the piston 25 correspond to the pre-break points of the first conductive bar 26 and the second conductive bar 28, respectively. A second cavity is provided in the lower housing 23, below the first cavity, that is, in front of the displacement path of the piston 25. Two thermal cutoffs 31 are disposed in the second cavity. The fuse element 1 of one thermal cutoff is connected in parallel to the first conductive bar 26, and the other thermal cutoff is connected in parallel to the second conductive bar 28. The thermal cutoff 31 comprises a assembled fuse housing, which includes a fuse body 32 and an upper cover 33. The fuse housing is filled with an arc-extinguishing medium, and a melt structure is provided in the arc-extinguishing medium. The insulating spacer 2 matches the shape of the inner wall of the fuse housing and is in sealed contact with the fuse housing, insulating and isolating the interior of the fuse housing into several independent and non-interconnected chambers. The melt 1 passes through the insulating spacer 2, the joint of the fuse housing 32 and the upper cover 33 and is connected in parallel with the corresponding conductive bar.

[0090] The excitation fuses in the above-described embodiments are all provided with a piston. In some embodiments, a piston may not be provided, and the driving force released by the excitation source directly acts on the conductive bar to disconnect the conductive bar. The driving force released by the excitation source can be high-pressure gas or mechanical force. When the excitation source releases mechanical force, such as a pneumatic cylinder, electric cylinder, or electromagnetic drive, the control circuit controls the operation of the pneumatic cylinder, electric cylinder, or electromagnetic drive to release the mechanical driving force. When action is required, the control circuit is controlled according to the trigger signal, thereby causing the excitation source of the pneumatic cylinder, electric cylinder, or electromagnetic drive to operate, releasing the mechanical force as the driving force and disconnecting the conductive bar.

[0091] As can be seen from the above description, when the melt structure is disposed in the second cavity serving as the arc extinguishing chamber, the shape of the insulating spacer 2 may or may not match the shape of the second cavity. Preferably, the insulating spacer matches the shape of the second cavity, forming a gapless assembly after assembly. That is, a sealed contact is formed between the insulating spacer and the second cavity, improving the insulation performance of the melt portion on both sides of the insulating spacer and enhancing the disconnection reliability.

[0092] When the shape of the insulating isolator does not match that of the second cavity, it is preferred that the insulating isolator and the second cavity are in sealed contact. The sealed contact is achieved by filling sealant between the insulating isolator and the second cavity to achieve sealed fixation, thereby improving the overall stability of the melt structure arranged in the second cavity, improving the insulation performance of the melt parts on both sides of the insulating isolator, and having high disconnection reliability and lower failure probability.

[0093] Preferably, the insulating spacer matches the shape of the second cavity, and a seal is performed between the insulating spacer and the second cavity, and a filling sealant is applied to seal the insulating spacer, so that the insulating spacer and the second cavity are more tightly bonded, the sealing performance is better, the melt structure is more stable, and the insulation performance and disconnection reliability are higher.

[0094] In the above embodiments, when there are two or more conductive bars, all of them are connected in parallel with the melt structure. In some embodiments, at least one conductive bar is connected in parallel with the melt structure, and the remaining conductive bars may or may not be connected in parallel with the melt structure according to design requirements.

[0095] In the above embodiment, except for the two ends where the melt is connected to the conductive bar, the entire melt structure is arranged in the arc-extinguishing medium of the second cavity, that is, the narrow neck of the melt, the insulating isolation piece, etc. of the melt structure are all arranged in the arc-extinguishing medium; in some embodiments, the melt structure can be partially arranged in the arc-extinguishing medium of the second cavity according to design requirements.

Claims

1. An excitation fuse with a melt structure, characterized in that: It includes a shell, an excitation source, at least one conductive bar, and a melt structure; A first cavity and a second cavity filled with an arc-extinguishing medium are provided in the housing; a chamber where a driving force release end of the excitation source is located is communicated with the first cavity, and the conductive bar passes through the housing and the first cavity; the melt structure is at least partially located in / or passes through the arc-extinguishing medium in the second cavity; The melt structure includes a melt and an insulating spacer; the melt passes through the arc-extinguishing medium in the second cavity, and both ends of the melt are conductively connected to the conductive bar in parallel. At least one insulating spacer is provided between both ends of the melt in the current direction. The melt passes through the insulating spacer, and the insulating spacer is provided in the arc-extinguishing medium in the second cavity. The insulating spacer is used to partially or completely isolate the arc at the melt break and release gas at the high temperature of the arc to cool the arc. When the excitation source is activated according to the received trigger signal and releases the driving force, the driving force acts on the conductive bar, causing the conductive bar to be disconnected and the fuse to melt.

2. The excitation fuse according to claim 1, characterized in that The insulating spacer and the melt are gap-fitted or sealed.

3. The excitation fuse according to claim 2, characterized in that When sealed, the insulating spacer and the melt are integrally injection-molded, or the gap between the insulating spacer and the melt is sealed by a sealant.

4. The excitation fuse according to claim 2, characterized in that The insulating spacer is provided with a notch or a through hole for the melt to pass through, and the melt passes through the notch or the through hole.

5. The excitation fuse according to claim 4, characterized in that The gap between the melt and the notch or through hole is filled with the sealant.

6. The excitation fuse according to claim 1, characterized in that The cross-sectional shape of the insulating spacer includes at least one angular shape, or at least a partially arcuate shape.

7. The excitation fuse according to claim 6, characterized in that The cross-sectional shape of the insulating spacer includes at least one of the following shapes: square, circle, diamond, and trapezoid.

8. The excitation fuse according to claim 1, characterized in that: A groove is provided on the surface of at least one side of the insulating spacer along the direction of the melt current.

9. The excitation fuse according to claim 1, characterized in that: The insulating spacer is made of insulating, high-temperature resistant and flame-retardant material.

10. The excitation fuse according to claim 9, characterized in that The insulating spacer is made of at least one of the following materials: rubber, ceramics, and engineering plastics. When ceramics are used, a gas-generating substance capable of releasing gas at high temperatures is provided on the ceramics.

11. The excitation fuse according to claim 1, characterized in that: A narrow neck of at least one specification is provided between the two ends of the melt, and the largest width of one side or both sides of the narrow neck in the current direction is a heat dissipation section; at least one insulating spacer is provided at the narrow neck or the heat dissipation section.

12. The excitation fuse according to claim 11, characterized in that When the narrow neck is provided with one specification, the melt includes an arc extinguishing section and a heat dissipation section, and the narrow neck is the arc extinguishing section; when the narrow neck is provided with two or more specifications, the melt includes an arc starting section, an arc extinguishing section and a heat dissipation section, the narrow neck that arcs and melts first is the arc starting section, and the narrow neck that arcs and melts later is the arc extinguishing section; at least one insulating isolation piece is provided at the arc starting section or the arc extinguishing section.

13. The excitation fuse according to claim 11, characterized in that The insulating spacer is arranged at the arc striking section.

14. The excitation fuse according to claim 1, characterized in that The shape of the insulating spacer matches the shape of the second cavity, and the insulating spacer isolates the second cavity into a plurality of independent chambers that are not connected to each other.

15. The excitation fuse according to claim 1, characterized in that The insulating spacer is in sealing contact with the second cavity, and the insulating spacer is used to isolate the second cavity into a plurality of independent chambers that are not connected to each other.

16. The excitation fuse according to claim 1, characterized in that The driving force released by the excitation source is high-pressure gas.

17. The excitation fuse according to any one of claims 1 to 16, characterized in that: It also includes a piston located in the first cavity, and the piston is arranged corresponding to the conductive row.

18. The excitation fuse according to claim 17, characterized in that The conductive bar includes at least two insulated conductive bars; the impact ends of the piston are respectively arranged corresponding to the conductive bars; the melt structure is connected in parallel to at least one of the conductive bars, and the melt structure is located in the second cavity.

19. The excitation fuse according to claim 18, characterized in that When there are two or more conductive bars, the conductive bars are arranged side by side, staggered in layers, or staggered in positions.

20. The excitation fuse according to claim 17, characterized in that A thermal cutout is disposed in the second cavity, and the fuse structure is disposed in the thermal cutout.

21. The excitation fuse according to claim 17, characterized in that The second cavity is located outside the piston displacement path or in front of the piston displacement path.

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