Melt structure and circuit protection device

Abstract

The invention relates to a melt structure and a circuit protection device. The melt structure comprises a melt and an insulating separator, at least one insulation isolation piece is arranged between the two ends of the current direction of the melt, the melt penetrates through the insulation isolation piece, and the insulation isolation piece is used for isolating and cooling an electric arc generated after the melt is disconnected and releasing gas under the action of the high temperature of the electric arc. The melt structure is integrally arranged in the circuit protection device, and the melt structure is connected with the external circuit in parallel or in series. When the fuse structure is applied to the circuit protection device, the breaking performance of the fuse and the insulating performance and the voltage resistance after breaking can be improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit protection, in particular to a melt structure used in the field of circuit protection, and in particular to a circuit protection device using the melt structure for circuit protection. Background Art

[0002] The main products for circuit overcurrent protection are thermal fuses and excitation fuses. Thermal fuses disconnect the circuit by melting, while excitation fuses disconnect the circuit by mechanical means.

[0003] The main structure of a thermal cutoff fuse includes an insulating shell, an arc-extinguishing medium, a melt, and a terminal block. The insulating shell is filled with an arc-extinguishing medium, and the melt is passed through the arc-extinguishing medium. A narrow neck is provided on the melt. The narrow diameter of the melt is the position on the melt with the smallest conductor cross-section, which is used to adjust the melting speed. The narrow neck is located in the arc-extinguishing medium, and the terminal blocks are located at both ends of the insulating shell and are conductively connected to the two ends of the melt. When the thermal cutoff fuse is connected in series in a protection circuit (such as in new energy vehicles and power equipment), the current flows through the melt and the narrow neck, and the heat generation and heat dissipation of the melt are kept in balance, and the thermal cutoff fuse conducts current normally. When an abnormal situation occurs (such as overload current or short-circuit current), the melt heats up rapidly, and the temperature rise is greater than the heat dissipation. The narrow neck of the melt melts first and an arc is struck. The melt is melted / vaporized by the thermal effect of the current, and a fracture is formed. The arc heat is absorbed by the arc-extinguishing medium, the arc temperature is reduced, and the molten metal particles at the fracture are wrapped and absorbed, thereby increasing the arc voltage and extinguishing the arc.

[0004] An excitation fuse generally includes an excitation source, a piston, and a conductive plate. The excitation source releases high-pressure gas as a driving force based on the received trigger signal, driving the piston to move. The piston breaks the conductive plate, thereby disconnecting the circuit and achieving circuit protection. In order to improve the breaking capacity and arc extinguishing capability, an arc-extinguishing fuse is connected in parallel with the conductive plate. The resistance of the arc-extinguishing fuse is much greater than that of the conductive plate. During normal current flow, most of the current flows through the conductive plate, and the current flowing through the arc-extinguishing fuse is negligible. When the conductive plate is disconnected, the current flows through the arc-extinguishing fuse, and the arc-extinguishing fuse melts or is mechanically disconnected. After the fuse is disconnected, the arc-extinguishing medium participates in extinguishing the arc.

[0005] 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 conductor diffusion and ceramicization occur; 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.). Summary of the Invention

[0006] The purpose of the present invention is to provide a melt structure and a circuit protection device, wherein an insulating isolator is provided through the melt structure to isolate the arc. The insulating isolator partially or completely vaporizes under the action of the high-temperature arc, and the released gas blows the arc, which is conducive to extinguishing the arc. The insulating isolator itself is made of an insulating material, which at least partially isolates the arcs on both sides to improve the insulation performance. It also expands and contracts the arc channel at high temperatures, and the effect is better under appropriate hardness. By providing an insulating isolator to actively extinguish the arc, the post-break insulation performance and arc extinguishing performance of the melt structure are improved. At the same time, the melt structure is used in the circuit protection device to improve the post-break insulation performance and breaking capacity of the circuit protection device.

[0007] To achieve the above-mentioned purpose, the present invention provides a melt structure, including a melt and an insulating isolator; at least one insulating isolator is arranged between the two ends of the current direction of the melt, and the melt passes through the insulating isolator. The insulating isolator is used to isolate and cool the arc generated after the melt is disconnected, and release gas under the action of the high temperature of the arc.

[0008] Preferably, the insulating spacer and the melt are gap-fitted or sealed.

[0009] 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.

[0010] 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.

[0011] Preferably, the gap between the melt and the notch or through hole is filled with the sealant.

[0012] Preferably, the cross-sectional shape of the insulating spacer includes: at least one angular shape, or at least partially an arc shape.

[0013] Preferably, the cross-sectional shape of the insulating spacer includes at least one of the following shapes: square, circle, diamond, and trapezoid.

[0014] Preferably, a groove is provided on the surface of at least one side of the insulating spacer along the direction of the melt current.

[0015] Preferably, the ratio of the thickness of the insulating spacer in the current direction to the length of the melt is in a range of 1:1000 to 1:5.

[0016] Preferably, the thickness of the insulating spacer in the current direction is 0.5 to 20 mm.

[0017] Preferably, the thickness of the insulating spacer in the current direction ranges from 0.5 to 3.5 mm.

[0018] Preferably, the insulating spacer has a thickness of 1.0 to 2.0 mm.

[0019] Preferably, the insulating spacer is made of an insulating, high-temperature resistant and flame-retardant material.

[0020] 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.

[0021] Preferably, the Shore hardness of the insulating spacer is in the range of 30 to 90 HA.

[0022] Preferably, the Shore hardness of the insulating spacer is in the range of 60 to 90 HA.

[0023] Preferably, the Shore hardness of the insulating spacer is 60HA, 70HA, 80HA or 90HA.

[0024] 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.

[0025] 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 striking section, an arc extinguishing section and a heat dissipation section, the narrow neck that arcs and melts first is the arc striking 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 striking section or the arc extinguishing section.

[0026] Preferably, at least one of the insulating spacers is arranged at the arc striking section.

[0027] The present invention further provides a circuit protection device for protecting an external circuit. The circuit protection device is integrated with the above-mentioned fuse structure, and the fuse structure is connected in parallel or in series with the external circuit.

[0028] Preferably, the circuit protection device includes an insulating shell, with terminals respectively provided at both ends of the insulating shell, an arc-extinguishing medium filled in the insulating shell, the melt structure passing through the arc-extinguishing medium, and the two ends of the melt respectively conductively connected to the terminals; the insulating isolation piece isolates the arcs generated at each fracture when the melt is blown, and the melt structure is connected in parallel or in series to the external circuit through the terminals.

[0029] Preferably, the circuit protection device includes an excitation source, a piston, and a conductor. The piston is arranged corresponding to the conductor. The melt structure is connected in parallel or in series to the conductor. The melt structure is passed through an arc extinguishing chamber filled with an arc extinguishing medium. The insulating isolation piece partially or completely isolates the arc generated at each fracture when the melt is melted; the conductor is used to be connected in series with an external circuit; the excitation source is actuated according to the received trigger signal, releasing a driving force to drive the piston to displace, and the piston drives the conductor to disconnect, and the melt structure is melted or mechanically disconnected by displacement of the piston.

[0030] Preferably, the outer shape of the insulating spacer matches the shape of the chamber where the arc extinguishing medium is located.

[0031] The melt structure of the present invention is used to isolate the arc generated after the melt is disconnected by piercing an insulating isolator on the melt structure to prevent arc breakdown; the insulating isolator is used to effectively reduce the arc near the insulating isolator and accelerate arc extinguishing. At the same time, the high temperature generated by the arc is used to vaporize the insulating tube isolator and blow away the metal ions near the insulating tube isolator, forming effective arc isolation and insulation, which fully improves the post-break insulation and voltage resistance performance of the product.

[0032] Circuit protection devices using the fuse structure of the present invention, such as thermal fuses and excitation fuses, can improve the breaking performance of the circuit protection device and the insulation performance and voltage resistance performance after breaking through the fuse structure of the present invention, effectively ensuring the reliability and stability of the circuit protection device's breaking; and improving the flexibility and adjustment range of the fuse scheme design of the circuit protection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a three-dimensional structural diagram of the melt structure.

[0034] Figure 2 It is a schematic diagram of the front view of the melt structure.

[0035] Figure 3 It is a schematic diagram of the melt structure from a top view.

[0036] Figure 4 It is a structural schematic diagram of an insulating spacer provided with a groove.

[0037] Figure 5 It is a structural schematic diagram of an insulating spacer provided with through holes.

[0038] Figure 6 It is a schematic diagram of a melt having a narrow neck of a certain specification.

[0039] Figure 7This is a schematic diagram of the principle structure of a thermal fuse using a melt structure.

[0040] Figure 8 yes Figure 7 A schematic diagram of the appearance of a specific structure.

[0041] Figure 9 yes Figure 8 Schematic diagram of the cross-sectional structure.

[0042] Figure 10 This is a schematic diagram of the structure of an excitation fuse using a melt structure.

[0043] Figure 11 It is a schematic diagram of a melt having two specifications of narrow necks.

[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, insulating tube shell 10, arc extinguishing medium 11, terminal 12, inner cap 13, outer cap 14, terminal 15, sealing ring 20, upper shell 21, middle shell 22, lower shell 23, excitation source 24, piston 25, conductor 26, arc extinguishing medium 27. DETAILED DESCRIPTION

[0046] The melt structure of the present invention includes a melt and an insulating spacer; at least one insulating spacer is provided between the two ends of the current direction of the melt, and the melt passes through the insulating spacer. The insulating spacer is used to isolate the arc generated after the cooling melt is disconnected, and release gas under the action of the high temperature of the arc.

[0047] The circuit protection device is used for protecting an external circuit. The above-mentioned fuse structure is integrated in the circuit protection device, and the fuse structure is connected in parallel or in series with the external circuit.

[0048] 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.

[0049] 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.

[0050] Several insulating spacers 2 are arranged on the melt 1 in the direction of current flow. Figures 1 to 3The insulating isolator 2 is arranged between the heat dissipation sections adjacent to each other in the direction of the current. During the melting process of the melt, the melt parts on both sides of the insulating isolator are isolated by the insulating isolator, and the arc is cooled by the gas released by the insulating isolator. 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. The insulating isolator 2 forms support for the melt 1 and isolates and cools the arc. The material of the insulating isolator 2 is an insulating material that can release gas at high temperature. It can include at least one of insulating, high-temperature resistant and flame-retardant materials such as rubber, ceramics, and engineering plastics. In a preferred embodiment, the insulating isolator can produce gas and release gas at the high temperature of the arc. Preferably, for example, 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.

[0051] The ratio of the thickness of the insulating spacer in the direction of current flow to the length of the melt is between 1:1000 and 1:5. The thickness of the insulating spacer is 0.5 to 20 mm, preferably 0.5 to 3.5 mm; more preferably 1.0 to 2.0 mm, with a specific thickness of 1.0 mm or 1.5 mm. The Shore hardness ranges from 30 to 90 HA, preferably 60 to 90 HA, with a specific Shore hardness of 60, 70, 80, or 90 HA. Within the Shore hardness range, higher hardness results in better results, and higher hardness results in easier processing.

[0052] 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 The insulating isolator 2 is 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 surfaces on both sides of the current direction of the square insulating isolator 2. 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. The melt 1 is fixed to the notch structure 4 of the insulating isolator 2 by the sealant, and the melt 1 is supported by the insulating isolator 2. The sealant uses 703 silicone and 5088 glue.

[0053] See Figure 5The insulating spacer 2 is a circular structure with a through-hole 5 at its center for the melt 1 to pass through. Grooves are provided on both sides of the insulating spacer 2, facing the current flow direction. The melt 1 passes through the through-hole 5 and is placed on the insulating spacer 2, which supports the melt 1. A clearance fit can be provided between the melt 1 and the through-hole 5, or the clearance can be filled with sealant. When the melt 1 and the insulating spacer 5 are clearance-fitted, the gap is sufficient to prevent arcs from passing through.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] At least one specification of narrow neck 6 is provided on the melt 1 in the direction of current flow. The specification of the narrow neck here refers to the width and shape of the narrow neck. "One specification" means the width and shape of the narrow neck are the same. "Two specifications" means the width and shape of the narrow neck are different.

[0060] 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.

[0061] 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.

[0062] See Figure 11 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 fuse 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 arc initiation section, and the second narrow neck 8, which arcs and blows later, is defined as the arc extinguishing section.

[0063] 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 striking section, an arc extinguishing section, and a heat dissipation section.

[0064] The insulating isolator 2 can be set at any of the arc-starting section, arc-extinguishing section and heat-dissipating section on the melt 1, and is suitable for application requirements under different arc-extinguishing and insulation performance. The insulating isolator is preferably set at the arc-starting section or the arc-extinguishing section, that is, at the narrow neck. When there are only arc-extinguishing sections and heat-dissipating sections in the melt, the insulating isolator is preferentially set at the arc-extinguishing section; when the insulating isolator is set at the narrow neck, the insulation performance of the melt after breaking is better and the arc duration is short. When the insulating isolator is set at 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-extinguishing section.

[0065] 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.

[0066] 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.

[0067] Regarding the circuit protection device of the above scheme, when the circuit protection device using the melt structure is a thermal fuse, the structural principle diagram is shown in FIG. Figure 7, including an insulating tube shell 10, a melt structure, an arc extinguishing medium 11, and a terminal 12. The insulating tube shell 10 is a tubular structure made of an insulating material, such as a plastic material, a ceramic material, etc. The insulating tube shell 10 is filled with an arc extinguishing medium 11. The melt structure is inserted into the arc extinguishing medium 11 in the insulating tube shell 10. The outer shape of the insulating isolator 2 matches the cross-sectional shape of the inner wall of the insulating tube shell 10, that is, the outer peripheral surface of the insulating isolator 2 contacts the inner wall of the insulating tube shell 10, and the insulating isolator 2 insulates and isolates the chambers in the insulating tube shell 10 on both sides of the insulating isolator 2. The outer peripheral surface of the insulating isolator 2 and the inner wall of the insulating tube shell 10 can be in a close fit relationship, or there can be an assembly gap. The setting method of the insulating isolator 2 is preferably perpendicular to the current direction of the melt 1, and the melt 1 is preferably set at the axial position of the insulating tube shell 10, which effectively improves the utilization rate of the arc extinguishing medium and at the same time improves the arc isolation of the insulating isolator 2, thereby fully releasing the insulation capacity. The insulating spacer 2 and the insulating shell 10 are fixed by a tight-fitting assembly method, or they can be fixed by gluing, for example, using 703 glue or 5088 glue, and filling the assembly gap between the insulating spacer 2 and the insulating shell 10 by gluing. The insulating spacer 2 located in the insulating shell 10 supports and isolates the melt 1, and the cavity in the insulating shell 10 is insulated and isolated by the insulating spacer 2 into a number of independent, non-interconnected cavities. The two ends of the melt 1 are conductively connected to the terminal blocks 12 located on the outside of the insulating shell 10, and the terminal blocks 12 serve as the connection ends for the thermal cutoff to connect to the external circuit. The heat dissipation section 3 of the melt 1 is arranged near the insulating shell 10. The heat energy generated by the melt 1 is dissipated through the heat dissipation section 3 to the arc extinguishing medium near the insulating shell 10, and then dissipated to the outside of the insulating shell 10 through the arc extinguishing medium and the insulating shell 10.

[0068] For the specific structure of thermal fuse, see Figures 8 and 9 , including an insulating shell 10, an arc-extinguishing medium 11, a melt structure, a conductive inner cap 13, an outer cap 14 and a terminal 15. The inner cap 13 and the outer cap 14 are provided at both ends of the insulating shell 10, and the inner cap 13 and the outer cap 14 seal the two ends of the insulating shell 10. The insulating shell 10 is filled with an arc-extinguishing medium 11, and the melt structure is passed through the arc-extinguishing medium 11. The two ends of the melt 1 of the melt structure are respectively conductively connected and fixed to the inner cap 13. The terminal 15 is located at both ends of the insulating shell 10, and is conductively connected to the two ends of the melt 1 through the outer cap 14 and the inner cap 13. The insulating spacer 2 is arranged in the insulating shell 10 in a manner perpendicular to the current direction and is sealed and fixed to the inner wall of the insulating shell 10.

[0069] Working principle of thermal fuse:

[0070] Thermal cutouts are used in circuits to protect them. Take the application of thermal melt fuses in the circuits of vehicles or electrical equipment as an example: when the vehicle or electrical equipment is in an abnormal working state, that is, when the current is in an overcurrent state, due to the thermal effect of the current, the narrow diameter position of the melt on the melt 1 first reaches its melting temperature and vaporization temperature, that is, the arc striking section on the melt 1 first reaches the melting temperature, and then the arc extinguishing section on the melt reaches the melting temperature. The melt 1 melts to form a fracture on the melt 1, and an arc column is generated at the fracture. Due to the insulating isolation effect of the insulating isolation part 2, that is, the insulating isolation part 2 is equivalent to a retaining wall, when the arc column passes through the insulating isolation part 2, the arc column becomes thinner and the arc size is effectively limited. With the help of the good cooling effect of the insulating isolation part 2, the arc temperature is reduced, the arc voltage is increased, and the current is reduced; at the same time, the insulating isolation part 2 generates a large amount of gas at high temperature, and the molten metal ions around the insulating isolation part 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 thermal melt fuse.

[0071] As a preferred embodiment, the circuit protection device described above may be an energizing fuse, contactor, other switch-like structure, or other circuit protection component integrated with the aforementioned melt structure. When integrating the aforementioned melt structure, the melt structure may be integrated into the circuit protection device in parallel or in series with a conductor within the circuit protection device that is electrically connected to an external circuit. Alternatively, a thermal cutoff fuse including the aforementioned melt structure may be directly integrated (including a thermal cutoff fuse with the aforementioned melt structure connected in parallel or in series with a conductor within the circuit protection component that is electrically connected to an external circuit, forming a circuit protection device with an integrated melt structure).

[0072] Take an excitation fuse with integrated melt structure as an example to illustrate, see Figure 10 , including a housing. In this embodiment, the housing is composed of an upper housing 21, a middle housing 22, and a lower housing 23. The structure of the housing is not limited to a structure composed of the upper housing 21, the middle housing 22, and the lower housing 23. It can also be a structure composed of left and right housings, or two or more housing parts. It also includes an excitation source 24, a piston 25, a conductor 26, an arc extinguishing medium 27, and a melt structure arranged in the housing. The resistance value of the melt 1 in the melt structure is much greater than the resistance value of the conductor 26. Under normal operating conditions, current flows through the conductor 26, and the current flowing through the melt 1 is negligible.

[0073] The excitation source 24 can release a driving force, which can be a mechanical driving force or a high-pressure gas or liquid. In a preferred embodiment, the excitation source can be a gas generating device, which can ignite according to the received trigger signal and release high-pressure gas as the driving force. The excitation source 24 and the piston 25 are respectively arranged 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 high-pressure gas 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, which is used 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 conductor 26 is located. The conductor 26 is passed between the upper shell 21 and the middle shell 22, and the piston 25 is located between the excitation source 24 and the conductor 26. A pre-break is formed on the conductor 26 to break the weak point, and the piston 25 is arranged corresponding to the pre-break of the conductor 26. A passage for the piston 5 to move and a space for the disconnected portion of the conductor 26 to slide down are provided in the upper shell 21 and the middle shell 22 .

[0074] An arc extinguishing chamber is provided in the lower shell 23, and an arc extinguishing medium 27 is filled in the arc extinguishing chamber. The melt structure is provided in the arc extinguishing medium 27 of the arc extinguishing chamber, wherein: the melt 1 of the melt structure is provided in the arc extinguishing medium 27, and the two ends of the melt 1 pass through the arc extinguishing chamber and the two outer sides of the current direction of the pre-break of the conductor 26 for conductive connection, so that the melt 1 is connected to the conductor 26 in a parallel manner, so that the melt 1 forms a parallel relationship with the pre-break of the conductor 26. The insulating isolation member 2 is in sealed contact with the inner wall of the arc extinguishing chamber, and the sealed contact method can be a close-fitting contact, or a sealant is filled in the contact gap to seal and fix it. The melt 1 is supported by the insulating isolation member 2, and at the same time, the arc extinguishing chamber is isolated by the insulating isolation member 2 into a number of independent, non-interconnected chambers.

[0075] Working principle:

[0076] During normal operation, current flows through the conductor 26 . The resistance of the fuse 1 is much greater than the resistance of the conductor 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 conductor 26 to form a break on the conductor 26. The current flows through the melt 1. When the melt 1 melts, an arc column is formed. Because the role of the insulating isolation piece 2 is equivalent to 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 the aforementioned energized fuse, the fuse 1 of the melt structure is thermally melted. In other embodiments, a displacement channel can be provided in the arc extinguishing chamber, through which the fuse 1 passes. A fuse-tightening assembly can be positioned within the displacement channel, projecting out of the displacement channel toward one end of the piston and positioned in the piston's displacement path. After the piston breaks the conductor, the piston continues to move, driving the fuse-tightening assembly along the displacement channel, mechanically breaking the fuse 1. When the overcurrent is high, the fuse 1 can melt first and then be mechanically disconnected. When the overcurrent is low, the fuse 1 is mechanically disconnected. Whether the fuse 1 melts or is mechanically disconnected, the fracture of the fuse 1 is located in the arc extinguishing medium. When the fuse 1 is mechanically disconnected, a weak point is formed in the fuse 1 located in the arc extinguishing medium. Due to the certain flexibility of the melt, when the fuse-tightening assembly displaces the portion of the melt in the displacement channel, the melt will pull through the weak point in the arc extinguishing medium, resulting in a mechanically disconnected fuse fracture located in the arc extinguishing medium.

Claims

1. A melt structure, characterized in that: It includes a melt and an insulating spacer; at least one insulating spacer is provided between the two ends of the current direction of the melt, the melt passes through the insulating spacer, and the insulating spacer is used to isolate and cool the arc generated after the melt is disconnected, and release gas under the action of the high temperature of the arc.

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

3. The melt structure 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 melt structure 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 melt structure 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 melt structure 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 melt structure 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 melt structure 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 melt structure according to claim 1, characterized in that The ratio of the thickness of the insulating spacer in the current direction to the length of the melt is in a range of 1:1000 to 1:

5.

10. The melt structure according to claim 9, characterized in that The thickness of the insulating spacer in the current direction is 0.5 to 20 mm.

11. The melt structure according to claim 10, characterized in that The thickness of the insulating spacer in the current direction ranges from 0.5 to 3.5 mm.

12. The melt structure according to claim 11, characterized in that The thickness of the insulating spacer is 1.0 to 2.0 mm.

13. The melt structure according to claim 1, characterized in that The insulating spacer is made of insulating, high-temperature resistant and flame-retardant material.

14. The melt structure according to claim 13, 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.

15. The melt structure according to claim 1, characterized in that The Shore hardness of the insulating spacer is in the range of 30 to 90 HA.

16. The melt structure according to claim 15, characterized in that The Shore hardness of the insulating spacer is in the range of 60 to 90 HA.

17. The melt structure according to claim 16, characterized in that The Shore hardness of the insulating spacer is 60HA, 70HA, 80HA or 90HA.

18. The melt structure 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.

19. The melt structure according to claim 18, 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 striking section, an arc extinguishing section and a heat dissipation section, the narrow neck that arcs and melts first is the arc striking 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 striking section or the arc extinguishing section.

20. The melt structure according to claim 19, characterized in that At least one of the insulating spacers is disposed at the arc striking section.

21. A circuit protection device, characterized in that: Used for protecting an external circuit, comprising: the circuit protection device is integrated with the melt structure according to any one of claims 1 to 20, and the melt structure is connected in parallel or in series with the external circuit.

22. The circuit protection device according to claim 21, wherein: The circuit protection device includes an insulating shell, with terminals provided at both ends of the insulating shell, an arc extinguishing medium filled in the insulating shell, the melt structure passing through the arc extinguishing medium, and both ends of the melt being conductively connected to the terminals. The insulating isolation piece isolates arcs generated at various fractures when the fuse is melted, and the fuse structure is connected in parallel or in series to the external circuit through the wiring terminal.

23. The circuit protection device according to claim 22, wherein: The circuit protection device includes an excitation source, a piston, and a conductor. The piston is arranged corresponding to the conductor. The melt structure is connected in parallel or in series to the conductor. The melt structure is arranged in an arc extinguishing chamber filled with an arc extinguishing medium. The insulating isolation piece partially or completely isolates the arc generated at each fracture when the melt is melted; the conductor is used to be connected in series with an external circuit; the excitation source is actuated according to the received trigger signal, releasing a driving force to drive the piston to displace, and the piston drives the conductor to disconnect, and the melt structure is melted or mechanically disconnected by the displacement of the piston.

24. The circuit protection device according to claim 23, wherein: The outer shape of the insulating spacer matches the shape of the chamber where the arc extinguishing medium is located.

Images