Melt structure and circuit protection device

Abstract

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

Description

Technical Field

[0001] This invention relates to the field of circuit protection, specifically a molten structure for circuit protection, and in particular a circuit protection device using the molten structure for circuit protection. Background Technology

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

[0003] The main structure of a thermoelectric fuse includes an insulating shell, an arc-extinguishing medium, a fusible element, and terminals. The insulating shell is filled with the arc-extinguishing medium, and the fusible element passes through it. A narrow neck is provided on the fusible element; this narrow neck is the position with the smallest conductor cross-section on the fusible element, used to adjust the melting speed. The narrow neck is located in the arc-extinguishing medium, and the terminals are located at both ends of the insulating shell, respectively connected to the two ends of the fusible element. When the thermoelectric fuse is connected in series in a protection circuit (such as in new energy vehicles and power equipment), current flows through the fusible element and the narrow neck. The heat generation and dissipation of the fusible element remain balanced, and the thermoelectric fuse conducts current normally. When an abnormal situation occurs (such as overload current or short-circuit current), the fusible element heats up rapidly, and the temperature rise exceeds the heat dissipation. The narrow neck of the fusible element melts first and an arc is ignited. The current heat effect melts / vaporizes the fusible element, forming a fracture. The arc-extinguishing medium absorbs the arc heat, lowers the arc temperature, and encapsulates and absorbs the molten metal particles at the fracture, increasing the arc voltage and extinguishing the arc.

[0004] An excitation fuse typically includes an excitation source, a piston, and a conductive plate. The excitation source, acting on a received trigger signal, releases high-pressure gas as the driving force, displacing the piston. The piston breaks the conductive plate, thus disconnecting the circuit and providing circuit protection. To improve breaking capacity and arc-extinguishing capability, an arc-extinguishing fusible element is connected in parallel on the conductive plate. The resistance of the arc-extinguishing fusible element is much greater than the resistance of the conductive plate. Under normal current flow, most of the current flows through the conductive plate, and the current flowing through the arc-extinguishing fusible element is negligible. When the conductive plate breaks, the current flows through the arc-extinguishing fusible element, which melts or is mechanically broken. After the fusible element breaks, the arc-extinguishing medium participates in arc extinguishing.

[0005] When both the fusible element of the thermal fuse and the arc-extinguishing fusible element of the excitation fuse are melted, the fusible element and its narrow diameter melt or vaporize, forming a break after melting. This is essentially a micro-explosion under overall safety control, as well as conductor diffusion and ceramization. Because physical insulation cannot be effectively established at the break, the diffusion of metal ions at the fusible element break is relatively random after the break, resulting in unstable or poor insulation performance after the break. Due to the poor or unstable insulation at the break, there is a risk of large leakage current, breakdown, and failure to break (explosion, etc.) under high voltage. Summary of the Invention

[0006] The purpose of this invention is to provide a molten structure and a circuit protection device. An insulating isolator is installed within the molten structure to isolate the electric arc. Under the influence of the high-temperature arc, the insulating isolator partially or completely vaporizes, and the released gas blows away the arc, which helps extinguish it. The insulating isolator itself is made of insulating material, providing at least partial isolation of the arc on both sides, thus improving insulation performance. Furthermore, it expands thermally at high temperatures, contracting the arc channel; the effect is even better at appropriate hardness. By actively extinguishing the arc with the insulating isolator, the post-break insulation performance and arc-extinguishing performance of the molten structure are improved. Simultaneously, the molten structure, when used in a circuit protection device, improves the post-break insulation performance and breaking capacity of the circuit protection device.

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

[0008] Preferably, the insulating insulating element and the molten material are gap-fitted or sealed together.

[0009] Preferably, when a sealed connection is made, the insulating insulating element and the melt are integrally injection molded, or the gap between the insulating insulating element and the melt is sealed with sealant.

[0010] Preferably, the insulating insulating element is provided with a notch or through hole through which the molten material passes.

[0011] Preferably, the sealant is used to fill the gap between the melt and the notch or through hole.

[0012] Preferably, the cross-sectional shape of the insulating insulating member includes at least one angular shape, or at least partially arcuate shape.

[0013] Preferably, the cross-sectional shape of the insulating insulating member includes at least one of the following shapes: square, circular, rhomboid, trapezoidal.

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

[0015] Preferably, the ratio of the thickness of the insulating isolator in the current direction to the length of the melt is between 1:1000 and 1:5.

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

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

[0018] Preferably, the thickness of the insulating insulating element is 1.0 to 2.0 mm.

[0019] Preferably, at least one type of narrow neck is provided between the two ends of the melt, and the section with the maximum width on one or both sides of the narrow neck in the direction of current is a heat dissipation section; at least one of the insulating isolation members is provided at the narrow neck or the heat dissipation section.

[0020] Preferably, when the neck is provided with one specification, the molten material includes an arc-extinguishing section and a heat dissipation section, and the neck is the arc-extinguishing section; when the neck is provided with two or more specifications, the molten material includes an arc-initiating section, an arc-extinguishing section and a heat dissipation section, the neck that first initiates the arc and melts is the arc-initiating section, and the neck that later initiates the arc and melts is the arc-extinguishing section; at least one insulating isolator is provided at the arc-initiating section or the arc-extinguishing section.

[0021] Preferably, at least one of the insulating insulating elements is disposed at the arc-starting segment.

[0022] The present invention also provides a circuit protection device for protecting an external circuit, wherein the circuit protection device integrates the above-mentioned fusible element structure, and the fusible element structure is connected in parallel or in series with the external circuit.

[0023] Preferably, the circuit protection device includes an insulating shell with terminals at both ends, an arc-extinguishing medium filling the insulating shell, a molten body structure passing through the arc-extinguishing medium, and both ends of the molten body being electrically connected to the terminals. The insulating isolator isolates the arc generated at each break point when the molten body melts. The molten body structure is connected in parallel or in series with the external circuit through the terminals.

[0024] Preferably, the circuit protection device includes an excitation source, a piston, and a conductor. The piston is positioned corresponding to the conductor. The molten structure is connected in parallel or series with the conductor. The molten structure passes through an arc-extinguishing chamber filled with an arc-extinguishing medium. The insulating isolator partially or completely isolates the arc generated at each break point when the molten structure melts. The conductor is used for series connection with an external circuit. The excitation source operates according to the received trigger signal, releasing a driving force to drive the piston to move. The piston drives the conductor to disconnect. The molten structure melts or is mechanically disconnected by the piston displacement.

[0025] Preferably, the shape of the insulating isolator matches the shape of the chamber where the arc-extinguishing medium is located.

[0026] The melt structure of the present invention, by inserting an insulating isolator on the melt structure, is used to isolate the electric arc generated after the melt breaks, and prevent arc breakdown. The insulating isolator effectively reduces the electric arc near the insulating isolator and accelerates arc extinguishing. At the same time, the high temperature generated by the electric arc causes the insulating tube isolator to vaporize, blowing away the metal ions near the insulating tube isolator, forming effective arc isolation and insulation, and significantly improving the insulation and withstand voltage performance of the product after breakage.

[0027] Circuit protection devices employing the fusible element structure of this invention, such as thermal fuses and excitation fuses, can improve the breaking performance, insulation performance, and withstand voltage performance of the circuit protection device after breaking by utilizing the fusible element structure of this invention, effectively ensuring the reliability and stability of the circuit protection device's breaking performance; and enhancing the flexibility and adjustment range of the fusible element design for the circuit protection device. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the three-dimensional structure of the melt.

[0029] Figure 2 This is a front view schematic diagram of the melt structure.

[0030] Figure 3 This is a top view schematic diagram of the melt structure.

[0031] Figure 4 This is a schematic diagram of an insulating insulating component with grooves.

[0032] Figure 5 This is a schematic diagram of an insulating insulating component with through holes.

[0033] Figure 6 This is a schematic diagram of a melt with a narrow neck of a certain specification.

[0034] Figure 7 This is a schematic diagram of the principle structure of a thermoelectric fuse that uses a fusible element structure.

[0035] Figure 8 yes Figure 7 A schematic diagram of the appearance of a specific structure.

[0036] Figure 9 yes Figure 8 A cross-sectional structural diagram.

[0037] Figure 10 This is a schematic diagram of an excitation fuse using a fusible element structure.

[0038] Figure 11 This is a schematic diagram of a melt with two different specifications of narrow necks.

[0039] Figure Labels

[0040] 1. Melt, 2. Insulating isolation component, 3. Heat dissipation section, 4. Notch structure, 5. Through hole, 6. Neck, 7. First neck, 8. Second neck, 10. Insulating tube shell, 11. Arc extinguishing medium, 12. Terminal block, 13. Inner cap, 14. Outer cap, 15. Terminal block, 20. Sealing ring, 21. Upper shell, 22. Middle shell, 23. Lower shell, 24. Excitation source, 25. Piston, 26. Conductor, 27. Arc extinguishing medium. Detailed Implementation

[0041] The melt structure of the present invention includes a melt and an insulating isolator; at least one insulating isolator is provided between the two ends of the melt in the current direction, the melt passes through the insulating isolator, the insulating isolator is used to isolate and cool the electric arc generated after the melt is disconnected, and releases gas under the high temperature of the electric arc.

[0042] A circuit protection device is used to protect external circuits. The circuit protection device integrates the aforementioned fusible element structure, which is connected in parallel or series with the external circuit.

[0043] The following describes preferred embodiments in detail with reference to the accompanying drawings. The directional terms used are for reference only and do not constitute a limitation on the technical solution of this invention.

[0044] Melt structure, see Figures 1 to 3 The system includes a melt 1, an insulating separator 2, and a heat dissipation section 3. The melt 1 is a long, sheet-like structure made of a conductive material. Several heat dissipation sections 3 are spaced along the current direction (i.e., the length direction) of the melt 1, with the heat dissipation section 3 having the largest cross-sectional area and the largest heat dissipation area. The heat dissipation sections 3 can quickly transfer the heat generated by the melt to the outside of the melt, thereby reducing the temperature of the melt.

[0045] Several insulating spacers 2 are spaced apart on the melt 1 in the direction of current flow, see [reference] Figures 1 to 3 The insulating isolator 2 is disposed between adjacent heat dissipation sections in the current direction. During the melting process of the melt, the insulating isolator isolates the melt portions on both sides of the insulating isolator, and simultaneously cools the arc by releasing gas from the insulating isolator. The maximum outer diameter of the insulating isolator 2 is greater than the maximum width of the melt structure, i.e., greater than the width of the heat dissipation section. The insulating isolator 2 provides support for the melt 1 and provides arc isolation and cooling. The insulating isolator 2 is made of an insulating material that can release gas at high temperatures. 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 generate 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.

[0046] The ratio of the thickness of the insulating separator in the current direction to the length of the melt ranges from 1:1000 to 1:5. The thickness of the insulating separator is 0.5–20 mm, preferably 0.5–3.5 mm; more preferably 1.0–2.0 mm, and can be specifically designed as 1.0 mm or 1.5 mm. The Shore hardness ranges from 30–90 HA, preferably 60–90 HA, and can be specifically designed as 60 HA, 70 HA, 80 HA, or 90 HA. Within the Shore hardness range, higher hardness results in better performance and easier processing.

[0047] The cross-sectional shape of the insulating separator 2 includes at least one angular shape, or at least partially arcuate shape, such as at least one of a square, circular, rhomboid, or trapezoidal structure. See also Figure 4 The insulating isolator 2 is square. To facilitate assembly between the insulating isolator 2 and the molten material, a notch structure 4 is provided on the insulating isolator 2 for the molten material 1 to pass through. The notch structure 4 extends through the thickness of the insulating isolator 2, i.e., both sides in the current direction. Grooves are provided on both sides of the square insulating isolator 2 in the current direction. When grooves are provided, the insulating isolator 2 is thinner in the middle and thicker at the edges, which facilitates assembly and operation and improves the operability of the process; at the same time, it increases the strength of the insulating isolator 2 without increasing the thickness of the molten material passing through. During assembly, the molten material 1 passes through the notch structure 4, and then the gap between the molten material 1 and the notch structure 4 is filled with sealant. The sealant fixes the molten material 1 to the notch structure 4 of the insulating isolator 2, and the insulating isolator 2 provides support for the molten material 1. The sealant used is 703 silicone and 5088 adhesive.

[0048] See Figure 5 The insulating isolator 2 has a circular structure with a through hole 5 at its center for the molten material 1 to pass through. Grooves are provided on both sides of the insulating isolator 2 in the direction of current. The molten material 1 passes through the through hole 5 and is positioned on the insulating isolator 2, which provides support for it. The molten material 1 and the through hole 5 can be in a clearance fit, or the clearance can be filled with sealant. When the molten material 1 and the insulating isolator 5 are in a clearance fit, the clearance is sufficient to prevent the electric arc from passing through.

[0049] The melt 1 and the insulating separator 2 can be independent components that are then assembled together, or they can be integrally molded by injection molding.

[0050] Depend on Figure 4 and Figure 5 It can be seen that the melt 1 passes through the insulating isolator 2, and the outer periphery of the melt 1 at the position where it passes through the insulating isolator 2 is completely covered by the insulating isolator 2, or the insulating isolator 2 is completely covered by the sealant, thus forming a complete isolation of the electric arc at the melt fracture.

[0051] In some embodiments, at least a portion of the melt 1 in the width direction may be surrounded by an insulating isolator 2, so that the insulating isolator 2 supports the melt 1, partially isolates the melt portions on both sides of the insulating isolator 2, and partially isolates the electric arc generated at the melt fracture.

[0052] Preferably, the insulating isolator 2 covers the outer periphery of the melt 1 and has a sealed contact with the melt 1, which improves the complete insulation and isolation performance of the melt portion on both sides of the insulating isolator 2 and the arc at the port. At the same time, it forms the most reliable support for the melt 1 and does not require additional support elements.

[0053] The insulating isolator 2 has grooves on both sides of the current direction surface. Alternatively, grooves can be provided on only one side surface. In some embodiments, grooves may not be provided.

[0054] At least one type of narrow neck 6 is provided on the melt 1 in the direction of current. The specifications of the narrow neck here refer to the width and shape of the narrow neck. One specification means that the width and shape of the narrow neck are the same. Two specifications of narrow necks mean that the width and shape of the narrow neck are different.

[0055] See Figures 1 to 2 The narrowest section of melt 1 is the neck 6, and the widest section is the heat dissipation section 3, which is located on one or both sides of the neck 6. Figure 1 and Figure 2 In the process, the narrowest part of the molten material 1 is divided into several segments, namely, several narrow necks 6 are provided on the molten material 1, and each narrow neck 6 has the same width and shape, that is, several narrow necks 6 of the same specification are provided on the molten material 1. When the molten material breaks, because the width is the narrowest at the narrow neck 6, the resistance is the highest, and the temperature rises the fastest at the narrow neck 6. The temperature at the narrow neck 6 first rises to the melting point of the molten material 1, and the molten material 1 breaks off by arc from the narrow neck 6. Since the narrow necks 6 are all of the same specification, there may be many narrow necks where the molten material 1 breaks off. Figure 1 and Figure 2 In the same specification, the narrow neck 6 is defined as the arc-extinguishing section. During the process of heating the narrow neck 6 to the point of melting, most of the heat energy at the narrow neck 6 is conducted along the length of the melt towards the heat dissipation section 3. Since the heat dissipation section 3 is wider and has a larger heat dissipation area, the heat dissipation effect through the heat dissipation section 3 is better than that through the narrow neck 6. Figure 1 and Figure 2 In the middle, the insulating isolation element 2 is set at the narrow neck 6, that is, at the arc extinguishing section.

[0056] See Figure 6Several identical necks 6 are provided on the melt 1 in the direction of current flow. The width of the neck 6 is the width of the melt through which the current flows. The width of the neck 6 (i.e., the actual width of the melt flowing through the neck, excluding the width of the through hole at the neck) is smaller than the width of the melt on one side of the neck 6 (the actual width of the melt flowing through). Therefore, the necks 6 of the same specification are all arc-extinguishing sections, and the part with the largest melt width on one or both sides of the neck 6 is the heat dissipation section 3.

[0057] See Figure 11 Two types of narrow necks are spaced apart on the melt 1 in the direction of current flow. The narrow neck with the smallest current-passing width is the first narrow neck 7, and the narrow neck with a larger current-passing width is the second narrow neck 8. The melt portion with the largest actual current-passing width located on one or both sides of the narrow neck is the heat dissipation section 3. The actual current-passing 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 the resistance at the second narrow neck 8. Therefore, when the melt melts, the heating rate of the first narrow neck 7 is greater than that of 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 is the first to arc and melt, and the second narrow neck 8 is the second to arc and melt. Therefore, the first narrow neck 7, which is the first to arc and melt, is defined as the arc-initiating section, and the second narrow neck 8, which is the second to arc and melt, is defined as the arc-extinguishing section.

[0058] 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 1, 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-initiating section, an arc-extinguishing section, and a heat dissipation section.

[0059] The insulating isolator 2 can be disposed at any point on the arc-initiating section, arc-extinguishing section, and heat-dissipating section of the molten material 1, suitable for application requirements with different arc-extinguishing and insulation performance. The insulating isolator is preferably disposed on the arc-initiating section or the arc-extinguishing section, that is, at the neck. When the molten material only has an arc-extinguishing section and a heat-dissipating section, the insulating isolator is preferentially disposed on the arc-extinguishing section. When the insulating isolator is disposed at the neck, the insulation performance after the molten material breaks is better, and the arc duration is shorter. When the insulating isolator is disposed on the arc-initiating section, it can improve the insulation performance after the break and reduce the arc energy during the breaking process. In some embodiments, at least one insulating isolator is disposed on the arc-extinguishing section.

[0060] The melting rate of melt 1 is adjusted by the actual flow width of the neck 6. The smaller the actual flow width, the greater the melting rate.

[0061] The aforementioned fusible element structure can be integrated into a circuit protection device for the protection of external circuits. When the circuit protection device is used for external circuit protection, the integrated fusible element structure is connected to the external circuit in series or parallel. For example, when the circuit protection device is a thermal fuse, the fusible element structure acts as the fuse element and is connected in series with the external circuit. When the fusible element structure melts, the external circuit is disconnected. When the circuit protection device is an activated fuse, the fusible element structure is connected in parallel to the conductor of the activated fuse. The conductor is connected in series with the external circuit, so the fusible element structure is connected in parallel with the external circuit. When the conductor of the activated fuse breaks, the fusible element structure melts or is mechanically disconnected, completely disconnecting the external circuit and achieving protection for the external circuit. The following describes the structure of thermal fuses and activated fuses using the aforementioned fusible element structure.

[0062] For circuit protection devices involving the above schemes, when the circuit protection device with a fusible element structure is a thermal fuse, please refer to the structural schematic diagram. Figure 7 The system includes an insulating shell 10, a molten material structure, an arc-extinguishing medium 11, and terminals 12. The insulating shell 10 is a tubular structure made of insulating material, such as plastic or ceramic. The arc-extinguishing medium 11 is filled inside the insulating shell 10. The molten material structure passes through the arc-extinguishing medium 11 within the insulating shell 10. The shape of the insulating isolator 2 matches the cross-sectional shape of the inner wall of the insulating shell 10; that is, the outer circumferential surface of the insulating isolator 2 contacts the inner wall of the insulating shell 10. The insulating isolator 2 insulates and isolates the chambers within the insulating shell 10 on both sides of the insulating isolator 2. The outer circumferential surface of the insulating isolator 2 and the inner wall of the insulating shell 10 can be in a tight fit or have an assembly gap. Preferably, the insulating isolator 2 is positioned perpendicular to the current direction of the molten material 1. The molten material 1 is preferably positioned at the axial center of the insulating shell 10, effectively improving the utilization rate of the arc-extinguishing medium and simultaneously enhancing the arc isolation capability of the insulating isolator 2, thus fully releasing its insulating capacity. The insulating isolator 2 is fixed to the insulating shell 10 through a tight fit assembly method, or it can be fixed by adhesive, such as using 703 glue or 5088 glue, to fill the assembly gap between the insulating isolator 2 and the insulating shell 10. The insulating isolator 2, located inside the insulating shell 10, provides support and isolation for the molten element 1, insulating and isolating the chambers inside the insulating shell 10 into several independent, non-interconnected chambers. The two ends of the molten element 1 are electrically connected to the terminals 12 located on the outside of the insulating shell 10, which serve as the connection terminals for the thermoelectric fuse to the external circuit. The heat dissipation section 3 of the molten element 1 is located close to the insulating shell 10. The heat generated by the molten element 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.

[0063] For the specific structure of the thermoelectric fuse, please refer to [link / reference]. Figures 8 to 9 The system includes an insulating shell 10, an arc-extinguishing medium 11, a molten body structure, a conductive inner cap 13, an outer cap 14, and terminals 15. The insulating shell 10 has an inner cap 13 and an outer cap 14 at both ends, sealing both ends of the insulating shell 10. The insulating shell 10 is filled with the arc-extinguishing medium 11, and a molten body structure passes through it. The two ends of the molten body 1 of the molten body structure are electrically connected and fixed to the inner cap 13. Terminals 15 are located at both ends of the insulating shell 10, passing through the outer cap 14 and the inner cap 13, and are electrically connected to the two ends of the molten body 1. An insulating isolator 2 is disposed within the insulating shell 10 perpendicular to the current direction and is in sealed contact with the inner wall of the insulating shell 10.

[0064] Working principle of thermoelectric fuse:

[0065] Thermal fuses are used in circuits for circuit protection. Taking the application of thermoplastic fuses in vehicle or power equipment circuits as an example: When the vehicle or power equipment is in an abnormal operating state, i.e., when the current is in an overcurrent state, due to the thermal effect of the current, the narrow section of the fusible element 1 first reaches its melting and vaporization temperatures. That is, the arc-initiating section of the fusible element 1 first reaches its melting temperature, followed by the arc-extinguishing section. The fusible element 1 melts, forming a fracture, and an arc column is generated at the fracture. Due to the insulating isolation element 2, i.e., the insulating isolation element 2 is equivalent to a barrier, when the arc column passes through the insulating isolation element 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 element 2, the arc temperature decreases, the arc voltage increases, and the current decreases. At the same time, the insulating isolation element 2 generates a large amount of gas at high temperature, and the molten metal ions around the insulating isolation element 2 are blown away, forming effective arc isolation and insulation at this position, which fully improves the post-break insulation and withstand voltage performance of the product, while ensuring the reliability of the thermoplastic fuse protection performance.

[0066] In one preferred embodiment, the circuit protection device described above can be an excitation fuse, contactor, other switching structure, or other components for circuit protection that integrate the aforementioned fusible element structure. When integrating the aforementioned fusible element structure, the fusible element structure can be integrated in parallel or in series with the conductor in the circuit protection device used for conductive connection to the external circuit. Alternatively, a thermal fuse including the aforementioned fusible element structure can be directly integrated (including a thermal fuse including the aforementioned fusible element structure connected in parallel or in series with the conductor in the circuit protection element that conductively connects to the external circuit, forming a circuit protection device with an integrated fusible element structure).

[0067] This explanation will take an integrated fusible element structure as an example. (See attached image.) Figure 10The system includes a housing, which in this embodiment is composed of an upper shell 21, a middle shell 22, and a lower shell 23. The structure of the housing is not limited to the combination of the upper shell 21, middle shell 22, and lower shell 23; it can also be composed of left and right sections, or two or more shell parts. The system also includes an excitation source 24, a piston 25, a conductor 26, an arc-extinguishing medium 27, and a melt structure disposed within the housing. The resistance of the melt 1 in the melt structure is much greater than the resistance of the conductor 26. Under normal operating conditions, current flows through the conductor 26, and the current flowing through the melt 1 is negligible.

[0068] The excitation source 24 can release driving force, which can be mechanical, high-pressure gas, or liquid. In a preferred embodiment, the excitation source can be a gas generator that ignites upon receiving a trigger signal, releasing high-pressure gas as the driving force. The excitation source 24 and piston 25 are respectively disposed within the upper shell 21. The excitation source 24 closes the top opening of the upper shell 21, and the end of the excitation source 24 that releases high-pressure gas faces 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 containing the end of the excitation source 24 that releases driving force communicates with the cavity containing the end of the piston away from the conductor 26. The conductor 26 passes between the upper shell 21 and the middle shell 22. The piston 25 is located between the excitation source 24 and the conductor 26. A pre-break is formed on the conductor 26 at a weak point, and the piston 25 is positioned corresponding to the pre-break of the conductor 26. The upper shell 21 and the middle shell 22 are provided with channels for the displacement of the piston 5 and space for the disconnected part to slide down after the conductor 26 is disconnected.

[0069] An arc-extinguishing chamber is provided in the lower shell 23, and the arc-extinguishing medium 27 is filled in the arc-extinguishing chamber. A molten body structure passes through the arc-extinguishing medium 27 in the arc-extinguishing chamber. Specifically, the molten body 1 of the molten body structure passes through the arc-extinguishing chamber and is electrically connected to the two outer sides of the pre-break point of the conductor 26 in the current direction, so that the molten body 1 is connected to the conductor 26 in parallel, forming a parallel relationship between the molten body 1 and the pre-break point of the conductor 26. An insulating isolator 2 is in sealed contact with the inner wall of the arc-extinguishing chamber. The sealing contact method can be a tight fit or a sealant filling the contact gap for sealing and fixation. The insulating isolator 2 supports the molten body 1 and simultaneously isolates the arc-extinguishing chamber into several independent, non-interconnected chambers.

[0070] Working principle:

[0071] During normal operation, current flows through conductor 26. The resistance of melt 1 is much greater than that of conductor 26, so the current flowing through melt 1 can be ignored.

[0072] When an abnormal situation occurs, i.e., an overcurrent, the excitation source 24 acts according to the received trigger signal, releasing high-pressure gas as a driving force to drive the piston 25 to move. The moving piston 25 breaks the pre-break of the conductor 26, forming a break on the conductor 26. The current flows through the molten element 1. When the molten element 1 melts, an arc column is formed. Because the insulating isolator 2 acts as a barrier, the arc column will immediately become thinner as it has to pass through the insulating isolator 2. The size of the arc column is effectively limited. With the help of the good cooling effect of the insulating isolator 2, the arc temperature decreases, the arc voltage increases, and the current decreases. At the same time, the insulating isolator 2 generates a large amount of gas at high temperature, and the molten metal ions around the insulating isolator 2 are blown away, forming effective arc isolation and insulation at this position. This fully improves the post-break insulation and withstand voltage performance of the product, while ensuring the reliability of the excitation fuse protection performance.

[0073] In the aforementioned excitation fuse, the fusible element 1 of the fusible structure is thermally melted and broken. In other embodiments, a displacement channel can be provided in the arc-extinguishing chamber, through which the fusible element 1 passes. A fusible element cutting assembly is provided in the displacement channel, with one end of the fusible element cutting assembly protruding from the displacement channel towards the piston. The fusible element cutting assembly is located on the piston's displacement path. After the piston breaks the conductor, the piston continues to move, driving the fusible element cutting assembly to move along the displacement channel, mechanically breaking the fusible element 1. When the overcurrent is large, the fusible element 1 can melt first and then be mechanically broken; when the overcurrent is small, the fusible element 1 is mechanically broken. Regardless of whether the fusible element 1 melts or is mechanically broken, the fracture surface of the fusible element 1 is located in the arc-extinguishing medium. When the fusible element 1 is mechanically broken, a weak point is provided on the fusible element 1 located in the arc-extinguishing medium. Due to the flexibility of the fusible element, when the fusible element cutting assembly moves, it carries the fusible element in the displacement channel, causing the fusible element to break at the weak point located in the arc-extinguishing medium, thus ensuring that the fracture surface of the mechanically broken fusible element is located in the arc-extinguishing medium.

Claims

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

2. The melt structure according to claim 1, characterized in that, The insulating insulating component is gap-fitted or sealed to the molten material.

3. The melt structure according to claim 2, characterized in that, When a sealed connection is made, the insulating isolation component is integrally injection molded with the melt, or the gap between the insulating isolation component and the melt is sealed with sealant.

4. The melt structure according to claim 3, characterized in that, The insulating isolator is provided with a notch or through hole through which the molten material passes.

5. The melt structure according to claim 4, characterized in that, The sealant is used to fill the gap between the melt and the notch or through hole.

6. The melt structure according to claim 1, characterized in that, The cross-sectional shape of the insulating insulating element includes at least one angular shape, or at least partially arcuate shape.

7. The melt structure according to claim 6, characterized in that, The cross-sectional shape of the insulating insulating element includes at least one of the following shapes: square, circular, rhomboid, and trapezoidal.

8. The melt structure according to claim 1, characterized in that, Along the direction of the melt current, a groove is provided on the surface of at least one side of the insulating isolator.

9. The melt structure according to claim 1, characterized in that, The ratio of the thickness of the insulating isolator in the current direction to the length of the melt is between 1:1000 and 1:

5.

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

11. The melt structure according to claim 10, characterized in that, The thickness of the insulating isolator in the direction of current is in the range of 0.5~3.5mm.

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

13. The melt structure according to claim 1, characterized in that, At least one type of narrow neck is provided between the two ends of the melt, and the section with the maximum width on one or both sides of the narrow neck in the direction of current is a heat dissipation section; at least one of the insulating isolation members is provided at the narrow neck or the heat dissipation section.

14. The melt structure according to claim 13, characterized in that, When the narrow neck of one specification is provided, the molten material includes an arc-extinguishing section and a heat dissipation section, and the narrow neck is the arc-extinguishing section; when the narrow neck of two or more specifications is provided, the molten material includes an arc-initiating section, an arc-extinguishing section and a heat dissipation section, the narrow neck where the arc is first ignited and melted is the arc-initiating section, and the narrow neck where the arc is later ignited and melted is the arc-extinguishing section; at least one of the insulating isolators is provided at the arc-initiating section or the arc-extinguishing section.

15. The melt structure according to claim 14, characterized in that, At least one of the insulating isolators is disposed at the arc-starting segment.

16. A circuit protection device, characterized in that, The protection device for external circuits includes: the circuit protection device integrating the molten structure according to any one of claims 1 to 15, wherein the molten structure is connected in parallel or in series with the external circuit.

17. The circuit protection device according to claim 16, characterized in that, The circuit protection device includes an insulating tube shell, with terminals provided at both ends of the insulating tube shell, an arc-extinguishing medium filled in the insulating tube shell, a molten body structure passing through the arc-extinguishing medium, and the two ends of the molten body being electrically connected to the terminals respectively. The insulating isolator isolates the electric arc generated at each break point when the molten material melts, and the molten material structure is connected in parallel or in series with the external circuit through the terminal block.

18. The circuit protection device according to claim 17, characterized in that, The circuit protection device includes an excitation source, a piston, and a conductor. The piston is positioned corresponding to the conductor. The molten structure is connected in parallel or series with the conductor. The molten structure passes through an arc-extinguishing chamber filled with an arc-extinguishing medium. The insulating isolator partially or completely isolates the electric arc generated at each break point when the molten structure melts. The conductor is used for series connection with an external circuit. The excitation source acts according to the received trigger signal, releasing a driving force to drive the piston to move. The piston drives the conductor to disconnect. The molten structure melts or is mechanically disconnected by the piston displacement.

19. The circuit protection device according to claim 18, characterized in that, The shape of the insulating isolator matches the shape of the chamber containing the arc-extinguishing medium.

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