A chip type three-terminal fuse with high breaking capacity

Abstract

The application relates to the technical field of fuses, in particular to a patch type three-terminal fuse with high breaking capacity. The three-terminal fuse comprises a three-terminal fuse main body and a FUSE; the three-terminal fuse main body comprises a main circuit, a fusible alloy in series on the main circuit and a heating element; the heating element is close to the fusible alloy; wherein the position of the heating element is arranged to make the heat of the heating element conduct to both ends of the fusible alloy, and at least two first fusible parts and second fusible parts which are synchronously triggered to fuse are formed on the fusible alloy; wherein the FUSE is in parallel with the fusible alloy. The scheme provides a patch type three-terminal fuse with high breaking capacity, so as to solve the problems that the traditional three-terminal fuse is insufficient in breaking capacity under a high-voltage scene, is easy to produce electric arc and cannot be flexibly adapted to voltage.

Description

Technical Field

[0001] This application relates to the field of fuse technology, and in particular to a surface mount three-terminal fuse with high breaking capacity. Background Technology

[0002] In high-voltage scenarios (>100V), traditional surface-mount three-terminal fuses often fail to completely interrupt fault current at a single melting point, easily leading to arcing or molten residue and protection failure. Relying solely on the main circuit thermal fusing mechanism of traditional three-terminal fuses lacks a backup protection path during high-voltage faults, posing a risk of thermal runaway. Furthermore, the breaking capacity of traditional three-terminal fuses is fixed and cannot be easily adjusted to meet customized requirements for different voltage levels (e.g., 500V→1000V).

[0003] Therefore, there is an urgent need for a surface-mount three-terminal fuse with high breaking capacity, adaptability to different voltage levels, and redundant protection function. Utility Model Content

[0004] The purpose of this invention is to provide a surface-mount three-terminal fuse with high breaking capacity to solve the problems of insufficient breaking capacity, easy arcing, and inability to flexibly adapt to voltage in traditional three-terminal fuses under high voltage scenarios.

[0005] This surface-mount three-terminal fuse with high breaking capacity includes a three-terminal fuse body and at least one FUSE. The three-terminal fuse body includes a main circuit, a fusible alloy connected in series with the main circuit, and a heating element. The two ends of the main circuit are main terminals, and a first connection terminal and a second connection terminal are formed at the two ends for connecting the main circuit to an external circuit. The heating element is close to the fusible alloy. The heating element is provided with a control terminal, and a third connection terminal is formed at the control terminal for connecting to an external control circuit. At least two synchronously triggered fusible portions, a first fusible part and a second fusible part, are formed on the fusible alloy. The FUSE is connected in parallel with the fusible alloy.

[0006] In some embodiments, a housing is also included, with the three-terminal fuse body and the FUSE disposed inside the housing.

[0007] In some embodiments, the fusible alloy is a sheet-like structure with uniform thickness; the heating area of ​​the heating element is arranged in the middle of the fusible alloy, so that the regions of the fusible alloy extending from the middle to both ends are respectively formed with a first fusible part and a second fusible part, and the first fusible part and the second fusible part are triggered to melt simultaneously.

[0008] In some embodiments, the FUSE includes a first FUSE and a second FUSE; wherein the first FUSE and the second FUSE are connected in series and then in parallel at both ends of the fusible alloy.

[0009] In some embodiments, the system further includes a PCB board; the three-terminal fuse body and the FUSE are respectively disposed on the PCB board; wherein the PCB board is provided with traces of the main circuit and traces of the parallel branch circuit, so that the FUSE is connected in parallel to both ends of the main circuit of the three-terminal fuse body.

[0010] In some embodiments, the heating element has a first electrode plate and a second electrode plate at both ends for connecting to an external circuit, so that the first electrode plate and the second electrode plate respectively form a first connection end and a second connection end; the heating area is centrally located below the fusible alloy, and the heating area forms a third connection end; the two ends of the fusible alloy are respectively connected to the first electrode plate and the second electrode plate, and the middle part is in contact with the heating area, and the heat generated by the heating area is uniformly conducted from the middle part of the fusible alloy to its two ends, so that the area extending from the middle part of the fusible alloy to its two ends respectively forms a first fusible part and a second fusible part.

[0011] In some embodiments, the housing further includes two bridging electrodes; the top of the housing has an opening and an internal partition plate that divides the inner cavity into a receiving groove and a bottom recess; the bottom recess of the housing is used to house the fusible alloy and the heating element, and the FUSE is disposed in the receiving groove; the partition plate of the housing has through holes for the bridging electrodes to pass through, so that the bridging electrodes pass through the receiving groove from below the partition plate of the housing; wherein the bottoms of the two bridging electrodes are respectively connected to the main circuit, and their tops are respectively connected to both ends of the FUSE.

[0012] In some embodiments, the device further includes a positioning block mounted in a receiving groove; the FUSE is a fuse; the positioning block has a first slot and a second slot on its two ends, and a plurality of locking grooves are arranged at intervals in its middle section, so that the fuse is spirally wound around the outer periphery of the positioning block, and its two ends are fixed at the first slot and the second slot, respectively.

[0013] In some embodiments, the two ends of the positioning block are conductive regions, and the middle section is an insulating region; the first slot and the second slot are located in the two conductive regions respectively; the two ends of the positioning block are respectively provided with openings for bridging electrodes to pass through, so that the two bridging electrodes are electrically connected to the two ends of the fuse at the first slot and the second slot respectively. In some embodiments, the inner wall of the receiving groove is provided with an inwardly protruding stepped structure, and the positioning block is mounted on the stepped structure of the protrusion.

[0014] In some embodiments, an arc-extinguishing chamber is formed within the receiving groove, and the arc-extinguishing chamber is filled with arc-extinguishing material or sealing material. In some embodiments, the surface of the fusible alloy is coated with a fusing agent.

[0015] This application has the following beneficial effects: This application proposes a collaborative breaking mechanism between a surface-mount three-terminal fuse and a FUSE, utilizing the electrical principle of parallel fuses. This mechanism enhances breaking reliability in high-voltage circuits. By employing a heating element and a fusible alloy to form a dual-fusible section that fuses synchronously, it improves breaking performance. This solution overcomes the single-point breaking limitation of traditional surface-mount three-terminal fuses in high-voltage scenarios, achieving linear enhancement of breaking capacity and improved system reliability. It also enables dynamic adjustment of breaking capacity, meeting the flexible adaptation requirements of multiple voltage levels.

[0016] Other features and beneficial effects of this application will be set forth in the following description, and some of the technical features and beneficial effects may be obvious from the description or learned by practicing this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the circuit structure of the three-terminal fuse provided in Embodiment 1 of this application.

[0019] Figure 2 This is a schematic diagram of the circuit structure of the three-terminal fuse provided in Embodiment 2 of this application.

[0020] Figure 3 This is a three-dimensional structural diagram of the three-terminal fuse body disposed on the PCB board according to Embodiment 3 of this application; Figure 4 This is a three-dimensional structural diagram of the three-terminal fuse body disposed on the PCB board according to Embodiment 4 of this application; Figure 5 This is a structural disassembly diagram of the three-terminal fuse body in embodiments 3-4 of this application; Figure 6 This is a three-dimensional structural diagram of the three-terminal fuse provided in Embodiment 5 of this application; Figure 7 This is a structural breakdown diagram of the three-terminal fuse provided in Embodiment 5 of this application; Figure 8 This is a cross-sectional view of the structure of the three-terminal fuse provided in Embodiment 5 of this application; Figure 9 This is a partial structural diagram of the three-terminal fuse provided in Embodiment 5 of this application. Figure 1 ; Figure 10 This is a schematic diagram of the heating element of the three-terminal fuse provided in Embodiment 5 of this application. Figure 1 ; Figure 11 This is a schematic diagram of the heating element of the three-terminal fuse provided in Embodiment 5 of this application. Figure 2 ; Figure 12 This is a schematic diagram of the positioning block of the three-terminal fuse provided in Embodiment 5 of this application; Figure 13 This is a partial structural diagram of the three-terminal fuse provided in Embodiment 5 of this application. Figure 1 ; Figure 14 This is a partial structural diagram of the three-terminal fuse provided in Embodiment 5 of this application. Figure 2 ; Figure 15 This is a partial structural diagram of the three-terminal fuse provided in Embodiment 5 of this application. Figure 3 .

[0021] Figure 16 This is a schematic diagram of the bottom structure of the three-terminal fuse provided in Embodiment 5 of this application; Figure 17 This is a schematic diagram of the bottom structure of the housing of the three-terminal fuse provided in Embodiment 5 of this application; Reference numerals: 100, PCB board; 200, three-terminal fuse body; 1, main circuit; P1, first connection terminal; P2, second connection terminal; P3, third connection terminal; 101, first fusible part; 102, second fusible part; 301, first fuse; 302, second fuse; 401, epoxy resin; 402, fuse wire; 403, positioning block; 404, housing; 405, fluxing agent; 406, bridging electrode; 407, fusible alloy; 408, heating element. Components; 404a, Arc extinguishing chamber; 4031, End regions; 4032, Middle region; 4033, First slot; 4034, Second slot; 4035, Positioning groove; 4036, Opening; 4037, First clearance groove; 4038, Second clearance groove; 4041, Protrusion; 4042, Bottom groove; 4043, Divider plate; 4044, Raised strip; 4081, First electrode plate; 4082, Second electrode plate; 4083, Heating area; 201, Shell cover. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The technical features designed in the different implementations of this application described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] In the description of this application, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."

[0024] This application provides surface mount three-terminal fuses with high breaking capacity as shown in Examples 1-5: Example 1, Infrastructure Pattern See Figure 1 This is a schematic diagram of a surface-mount three-terminal fuse with high breaking capacity provided in the first embodiment of the present invention. The surface-mount three-terminal fuse is as follows: The device includes a three-terminal fuse body 200 and a FUSE. The three-terminal fuse body 200 includes a main circuit 1, a fusible alloy 407 connected in series with the main circuit 1, and a heating element 408. The two ends of the main circuit 1 are main terminals, and a first connection terminal P1 and a second connection terminal P2 are formed at the two ends for connecting the main circuit 1 to an external circuit. The heating element 408 is located near the fusible alloy 407. The heating element 408 is provided with a control terminal, and a third connection terminal P3 is formed at the control terminal for connecting to an external control circuit. The heating element 408 is positioned such that its heat can be conducted to both ends of the fusible alloy 407, and at least two synchronously triggered fusible portions 101 and 102 are formed on the fusible alloy 407. The FUSE is connected in parallel to both ends of the fusible alloy 407.

[0025] Its specific working process is as follows: Under rated high voltage (e.g., system voltage 100VDC~500VDC): When an overcurrent occurs in the circuit, the fusible alloy 407 generates Joule heat and melts itself; or when an overcharge occurs, the controlled circuit formed by the control circuit activates the heating element 408, which heats up and is conducted to the fusible alloy 407. Through the specific positional design of the heating element 408 and the fusible alloy 407, the fusible alloy 407 melts simultaneously at its two fusible sections, namely the first fusible section 101 and the second fusible section 102, thereby improving the breaking effect. After the first fusible section 101 and the second fusible section 102 of the fusible alloy 407 are broken, the fault current is completely transferred to the FUSE in the parallel branch. The FUSE melts under the current surge, ultimately achieving complete circuit disconnection.

[0026] Optionally, the specific positions of the heating element 408 and the fusible alloy 407 are designed such that the heating element 408 (its heating area 4083) is centrally located in the middle region of the fusible alloy 407, ensuring that when triggered, the heat of the heating area 4083 is evenly conducted to the two fusible parts of the fusible alloy 407, and they melt simultaneously under the same thermal environment, thereby improving the breaking performance.

[0027] It should be noted that the material of fusible alloy 407 includes, but is not limited to, materials composed of quaternary alloys of Sn, Ag, Pb and Cu, which can be melted at a certain temperature.

[0028] In summary, this embodiment 1 design improves high-voltage breaking capacity by dispersing energy through parallel FUSE, and solves the problem of thermal runaway caused by single-point breaking failure of traditional three-terminal fuses under high voltage of 100VDC to 500VDC.

[0029] This mode uses a main circuit 1 with a series fusible alloy 407 and a high-melting-point FUSE in parallel (high melting point means the melting point of the FUSE is higher than that of the fusible alloy 407). When in use, the heating area 4083 of the heating element 408 triggers the two fusible sections of the fusible alloy 407 to melt simultaneously, and the fault current is transferred to the FUSE to complete the final disconnection. It is suitable for 100V~500VDC scenarios and solves the problem of single-point failure.

[0030] Example 2, Redundancy Enhancement Mode: Furthermore, to further improve the system, the number of FUSEs can be increased on the parallel branches to meet the application requirements of higher electrical architectures.

[0031] See Figure 2 Based on the architecture of Embodiment 1, a second FUSE 302 is added to the parallel branch where a first FUSE 301 is provided. Specifically, the two FUSEs in the parallel branch are connected in series and then connected in parallel to both ends of the fusible alloy 407.

[0032] In circuits rated for high voltage (e.g., 500VDC to 1000VDC), when overcurrent or overvoltage occurs, the fusible alloy 407 disconnects, and the current is transferred to the parallel FUSE. In high-voltage systems, due to the large energy generated during disconnection, there is a certain time difference between the disconnection of the two FUSEs. If one of them fails to disconnect, the other can provide a redundant protection channel to reduce the disconnection energy and achieve a final safe disconnection.

[0033] In summary, this embodiment 1 adds a parallel FUSE to the basic architecture to form dual-branch redundancy; during disconnection, the FUSE disconnection time difference under high voltage (500V~1000VDC) can provide dual protection, improve the breaking capacity and adapt to higher voltage requirements.

[0034] It should be noted that: Fuse includes, but is not limited to, fusible links, 402 fuses, current fuses, etc.

[0035] Examples 3-4, Integrated Module Mode: Based on the architecture of Embodiment 2, Embodiments 3-4 further optimize the physical layout of the parallel FUSE, that is, the three-terminal fuse body 200 and the FUSE are directly mounted on the PCB board 100. The specific technical solution is as follows: See Figure 3-5A surface-mount three-terminal fuse with high breaking capacity includes a PCB board 100, a three-terminal fuse body 200, and a fuse holder (FUSE). The three-terminal fuse body 200 and the FUSE are respectively mounted on the PCB board 100. The PCB board 100 is designed with a multi-layer structure, and the PCB board 100 has traces for the main circuit 1 and parallel branches, so that the FUSE is connected in parallel to both ends of the main circuit 1 of the three-terminal fuse body 200. Optionally, the FUSE and the three-terminal fuse body 200 are soldered to the PCB board 100 using SMT (Surface Mount Technology). The FUSE is connected in series in the parallel branches and then in parallel to both ends of the main circuit 1 of the three-terminal fuse body 200. This achieves electrical parallel connection, forming an integrated protection module. In specific use, when the main circuit 1 of the three-terminal fuse body 200 is triggered by overcurrent or overvoltage, causing the fusible alloy 407 to melt, the fault current is transferred to the parallel FUSE through the traces on the PCB, achieving final breaking.

[0036] Optionally, the main circuit 1 is connected to the parallel branch through copper foil traces to ensure low impedance and high heat dissipation performance.

[0037] In addition, in this embodiment, the three-terminal fuse body 200 and the FUSE are two separate modules, which are fixed on the PCB board 100 respectively. Optionally, the three-terminal fuse body 200 adopts a compact, space-saving surface mount design. like Figure 5 As shown, the fusible alloy 407 has a uniformly thick sheet structure, ensuring that the first fusible portion 101 and the second fusible portion 102 are triggered synchronously. The heating area 4083 of the heating element 408 is arranged in the middle of the fusible alloy 407, so that the regions of the fusible alloy 407 extending from the middle to both ends respectively form the first fusible portion 101 and the second fusible portion 102, and the first fusible portion 101 and the second fusible portion 102 are triggered to melt synchronously. With this design, the heating element 408 uniformly conducts heat from the middle of the fusible alloy 407 to both ends, so that the first fusible portion 101 and the second fusible portion 102 formed from the middle to both ends melt synchronously under the same thermal environment, thereby improving the breaking performance.

[0038] Furthermore, such as Figure 5 As shown, the three-terminal fuse body 200 adopts a surface-mount modular design, preferably integrating it into a compact module: Optionally, the fusible alloy 407 is a sheet-like structure with uniform thickness; the heating element 408 has a first electrode sheet 4081 and a second electrode sheet 4082 at both ends for connection to an external circuit, so that the first electrode sheet 4081 and the second electrode sheet 4082 respectively form a first connection end P1 and a second connection end P2; the heating element 408 has a heating area 4083 in the middle for heating, and the heating area 4083 is centrally located below the fusible alloy 407. The lead-out end of the heating area 4083 is the third connection end P3, which is connected to the controller after being led out. The two ends of the fusible alloy 407 are respectively connected to the first electrode plate 4081 and the second electrode plate 4082, and the middle part is in contact with the heating area 4083. The heat generated by the heating area 4083 is evenly conducted from the middle part of the fusible alloy 407 to its two ends, so that the area extending from the middle part of the fusible alloy 407 to its two ends respectively forms the first fusible part 101 and the second fusible part 102. Further, it also includes a cover 201 for covering the heating element 408 and the fusible alloy 407. With this design, the three-terminal fuse body 200 forms a compact modular whole. In use, the three-terminal fuse body 200 only needs to be fixed in the PCB board 100, and the first connection end P1 formed by the first electrode plate 4081 and the second electrode plate 4082 of the three-terminal fuse body 200 can be connected to the wiring of the main circuit 1.

[0039] Optionally, the surface of the fusible alloy 407 is coated with a fusing agent 405 to ensure complete breakage.

[0040] Optionally, at least two reserved pads for mounting the FUSE can be provided on the PCB board 100. Several FUSEs are fixed at the reserved pads so that the several FUSEs are connected in series in parallel branches and then connected in parallel to the two ends of the main circuit 1 of the three-terminal fuse body 200. With the above design, the number of FUSEs can be flexibly increased or decreased according to the voltage level (e.g., 500VDC to 1000VDC).

[0041] In summary, the integrated design described in Embodiments 3-4 reduces the size of traditional three-terminal fuses and is suitable for high-density circuit layouts. The three-terminal fuse body 200 and the FUSE are integrated on the PCB board 100, using surface mount technology (SMT) for soldering, and support pad expansion to adapt to 500V~1000VDC, reducing size and optimizing heat dissipation response.

[0042] It should be noted that, in specific implementations, the external dimensions of the parallel FUSE can support diverse designs, including but not limited to... Figure 3 The square package shown is Figure 4 The specific choice of the cylindrical package shown depends on the breaking capacity requirements and the layout constraints of the PCB board 100.

[0043] Example 5, Design of Product Integrated Arc Extinguishing Module: This embodiment provides another surface-mount three-terminal fuse with high breaking capacity, featuring an integrated arc-extinguishing module design: see [link to product details]. Figure 6-17 The product structure diagram shown indicates that the FUSE uses a fuse 402. The three-terminal fuse includes epoxy resin 401, fuse 402, positioning block 403, housing 404, flux 405, bridging electrode 406, fusible alloy 407, and heating element 408.

[0044] Structural optimization of the three-terminal fuse body 200: Optionally, the fusible alloy 407 is a sheet-like structure with uniform thickness; the heating element 408 has a first electrode sheet 4081 and a second electrode sheet 4082 at both ends for connection to an external circuit, so that the first electrode sheet 4081 and the second electrode sheet 4082 respectively form the first connection terminal P1 and the second connection terminal P2 of the main circuit 1, and the first connection terminal P1 and the second connection terminal P2 are used to connect to the external circuit; the heating element 408 has a heating area 4083 in the middle for heating, and the heating area 4083 is centrally located on the fusible alloy. Below the gold 407, the lead-out end of the heating area 4083 forms a third connection terminal P3, which is used to connect to an external control circuit, forming a controlled loop. The two ends of the fusible alloy 407 are respectively connected to the first electrode plate 4081 and the second electrode plate 4082, and its middle portion contacts the heating area 4083. The heat generated by the heating area 4083 is uniformly conducted from the middle of the fusible alloy 407 to its two ends, so that the regions extending from the middle to the two ends of the fusible alloy 407 respectively form a first fusible section 101 and a second fusible section 102. With this design, the heating element 408 uniformly conducts heat from the middle of the fusible alloy 407 to both ends, causing the first fusible section 101 and the second fusible section 102 formed from the middle to the two ends to melt synchronously under the same thermal environment, thereby improving breaking performance. Furthermore, this design makes the three-terminal fuse body 200 a compact unit, which is convenient for placement at the bottom of the housing 404 in this embodiment, improving the compactness of the device's structural layout.

[0045] Optionally, the fusible alloy 407 is fixed by SMT process to ensure that the heat from the heating element 408 can be evenly conducted to both ends of the fusible alloy 407 when triggered. Optionally, the surface of the fusible alloy 407 is coated with a fusing agent 405 to ensure complete breakage.

[0046] Optimized design for parallel connection of the FUSE and heating element 408 (connecting the FUSE in parallel inside the housing 404): Optionally, the housing 404 has an opening at the top and a partition plate 4043 inside. A receiving groove is formed above the partition plate 4043, and a bottom groove 4042 is formed below it. The fusible alloy 407 and the heating element 408 are arranged below the partition plate 4043 of the housing 404, and the FUSE is disposed in the receiving groove. The partition plate 4043 of the housing 404 has a through hole for the bridging electrode 406 to pass through, so that the bridging electrode 406 passes through and is interference-fitted with the through hole, passing through from below the partition plate 4043 of the housing 404 into its receiving groove. The bottoms of the two bridging electrodes 406 are respectively connected to the first electrode plate 4081 and the second electrode plate 4082, and their tops are respectively connected to the two ends of the FUSE.

[0047] With this design, the bridging electrode 406 extends from top to bottom into the inner cavity (i.e., the receiving groove) of the housing 404 and is electrically connected to the fuse 402, realizing the parallel connection of the fuse 402 and the main circuit 1. Furthermore, the interference fit between the bridging electrode 406 and the through-hole achieves hermetic sealing, preventing arc leakage. During use, fault current is transferred to the parallel-connected fuse 402 through the bridging electrode 406. Connecting the fuse in parallel inside the fuse body further facilitates its layout on the PCB.

[0048] Optionally, the bridging electrode 406 is soldered to the first electrode plate 4081 and the second electrode plate 4082 using an SMT process.

[0049] For the optimized design of the structure and location arrangement of parallel FUSE: Optionally, the positioning block 403 has a first slot 4033 and a second slot 4034 on its two end regions 4031, and a plurality of locking grooves 4035 are arranged at intervals in its middle section region 4032, so that the fuse 402 is spirally wound around the outer periphery of the positioning block 403, and its two ends are respectively fixed at the first slot 4033 and the second slot 4034. Optionally, the positioning block 403 has two end regions 4031 as conductive regions and its middle section region 4032 as an insulating region; the first slot 4033 and the second slot 4034 are located in two conductive regions; the positioning block 403 has two end regions 4031 as having openings 4036 for the bridging electrodes 406 to pass through, so that the tops of the two bridging electrodes 406 are electrically connected to the two end regions 4031 of the positioning block 403, and electrically connected to the two ends of the fuse 402 at the first slot 4033 and the second slot 4034, respectively.

[0050] The two ends of the fuse 402 are fixed by the first slot 4033 and the second slot 4034 of the positioning block 403, and the fuse 402 is spirally wound on the positioning groove 4035 of the positioning block 403 to achieve the pre-tightening force of the spiral winding of the fuse 402, ensuring that the stress of the fuse 402 is evenly distributed when it breaks. The pre-tightening force design ensures that each turn of the fuse 402 is heated synchronously. Compared with the straight fuse 402, the spiral structure design increases the effective length of the fuse 402. By separating the spacing of each turn of the fuse 402 to form a multi-segment melting point, the arc energy accumulation caused by single-point concentrated melting is avoided.

[0051] Optionally, such as Figure 14 As shown, the inner wall of the receiving groove is provided with an inwardly protruding stepped protrusion 4041, and the positioning block 403 is mounted on the stepped structure of the protrusion 4041. Through the cooperation between the stepped protrusion 4041 and the positioning block 403, the fuse 402 is mounted in the arc-extinguishing chamber 404a.

[0052] Optionally, such as Figure 14 and Figure 11 As shown, the two ends of the positioning block 403 are respectively provided with a first clearance groove 4037 and a second clearance groove 4038 that match the protrusion 4041, so that when the positioning block 403 is mounted on the stepped structure of the protrusion 4041, the protrusion 4041 is embedded in the first clearance groove 4037 and the second clearance groove 4038, which is used to improve the overall installation stability.

[0053] Optionally, the recessed receiving groove in the housing 404 forms a dedicated arc-extinguishing chamber 404a, which is filled with arc-extinguishing material or sealing material, such as epoxy resin 401 vacuum injection or quartz sand filling, to suppress the electric arc through a dual mechanism of physical isolation and chemical heat absorption.

[0054] Optionally, a bottom groove 4042 is formed on the lower surface of the partition plate 4043 of the housing 404. The bottom groove 4042 is used to accommodate the fusible alloy 407 and the heating element 408. This design improves the overall compactness of the device layout and enhances the breaking capacity of the fuse while maintaining a small overall size, overcoming the limitation of the weak breaking capacity of traditional surface-mount thermal fuses.

[0055] Furthermore, a downwardly protruding ridge 4044 may be provided on the lower surface of the partition plate 4043, which serves to fix the flux 405 and prevent the flux 405 from flowing.

[0056] In summary, in this embodiment 5, when an overcurrent occurs in the circuit, the fusible alloy 407 generates Joule heat and melts itself; or when an overvoltage occurs, the heating element 408 triggers the fusible alloy 407 to melt and break the main circuit 1. After the main circuit 1 is broken, the fault current is transferred to the parallel fuse 402 through the bridging electrode 406. The fuse 402 completes the final breakage in the arc-extinguishing chamber 404a, using epoxy resin 401 or quartz sand to extinguish the arc, suppressing the 1000VDC level arc through physical isolation or chemical heat absorption mechanisms. Preferably, the parallel fuse 402 adopts a spiral winding pre-tightening design, dispersing energy through multi-segment melting points to avoid single-point arc accumulation.

[0057] It should be noted that in embodiments 1-5 of this paper, the heating area 4083 of the heating element 408 is centrally located in the middle of the same fusible alloy 407, so that two fusible portions that melt synchronously are formed from the middle to both ends. Based on the design concept of this application, it is not limited to the scheme of setting the heating area 4083 of the heating element 408 in the middle of the same fusible alloy 407. In order to achieve the main circuit 1 having two or more fusible portions that melt synchronously to form a fracture, other schemes can also be adopted. For example, two independent fusible alloys 407 are connected in series in the main circuit 1, and the heating area 4083 can be uniformly conducted to the two independent fusible alloys 407 through specific position design of the heating element 408 and the two independent fusible alloys 407, so that the two melt synchronously, which can also achieve the effect required by this application. The embodiments of this application are only examples and include, but are not limited to, the embodiment schemes.

[0058] In summary, the surface-mount three-terminal fuse with high breaking capacity provided in this application has the following core design points, design concepts, and beneficial effects: 1. Utilizing the electrical principles of parallel fuses In DC circuits, parallel-connected fault current devices (FUSEs) follow Kirchhoff's Current Law (KCL), distributing fault current proportionally to branch impedance. Initially, the fusible alloy in the main circuit carries most of the current due to its lower impedance. When an overcurrent occurs, the fusible alloy melts first, and the current is then transferred to the higher-impedance parallel FUSE, achieving secondary interruption. Through the redundant design of the parallel FUSEs, after the fusible alloy in the main circuit melts, the fault current is transferred to the FUSE for secondary interruption, greatly improving the breaking capacity and reliability of high-voltage DC circuits.

[0059] In high-voltage scenarios (e.g., 100V-1000V), single-point interruption can easily generate arcing. By using parallel fuses or multi-path redundant interruption settings, the fault energy is distributed to multiple paths, thereby reducing the pressure on a single fuse point. For example, the single fuse in Example 1 is suitable for voltages below 500V, where energy is concentrated in a single channel during interruption; the dual fuse design in Example 2 is adapted to 1000V, where energy is distributed across two paths, and combined with time-difference gradient fusing, arcing can be further suppressed.

[0060] By increasing or decreasing the number of parallel FUSE connections, the requirements of different voltage levels from 100V to 1000V can be flexibly adapted, achieving dynamic adjustment of breaking capacity.

[0061] 2. Coordinated Disconnection Mechanism of Three-Terminal Fuse and FUSE Main circuit priority melting: Fusible alloys melt synchronously under overcurrent or heating element triggering, cutting off the main current path; Redundant protection: High-voltage interruption redundancy is achieved through parallel / multi-path design, and the limitations of traditional single-point fusing are solved by combining material optimization and structural innovation. Synchronous melting control: The heating area of ​​the heating element is specifically arranged so that the heat is evenly conducted to the two fusible parts on both sides of the fusible alloy, so that the two fusible parts melt synchronously and avoid current concentration caused by asynchronous melting.

[0062] Traditional three-terminal fuses are prone to failure in high-voltage scenarios due to insufficient single-point breaking capacity. However, the solution proposed in this application improves the overall breaking capacity linearly by using parallel FUSE / multi-path settings to collaboratively break fault currents.

[0063] 3. Other safety, reliability, and usability optimization designs: The design employs an integrated arc-extinguishing module (such as a spiral fuse and arc-extinguishing chamber filling) formed by the combination of the shell and the fuse, which effectively disperses and suppresses arc energy and improves the safety of the break.

[0064] Integrated modular design (such as PCB integration) makes products small in size, suitable for high-density circuit layouts, and easy to manufacture and maintain.

[0065] This application proposes a collaborative breaking mechanism between a three-terminal fuse and a FUSE, utilizing the electrical principle of parallel fuses. This mechanism enhances the breaking reliability under high-voltage circuits. By employing a heating element and a fusible alloy to form a dual-fusible part that fuses synchronously, it improves breaking performance. This solution overcomes the single-point breaking limitation of traditional surface-mount three-terminal fuses in high-voltage scenarios, achieving linear enhancement of breaking capacity and improved system reliability. It also enables dynamic adjustment of breaking capacity, meeting the flexible adaptation requirements of multiple voltage level scenarios.

[0066] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of this application can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A surface-mount three-terminal fuse with high breaking capacity, characterized in that, Includes a three-terminal fuse body (200) and at least one fuse; The three-terminal fuse body (200) includes a main circuit (1), a fusible alloy (407) connected in series with the main circuit (1), and a heating element (408). The two ends of the main circuit (1) are main terminals, and a first connection terminal (P1) and a second connection terminal (P2) are formed at the two ends for connecting the main circuit (1) to an external circuit. The heating element (408) is close to the fusible alloy (407); the heating element (408) is provided with a control terminal, and a third connection terminal (P3) for connecting to an external control circuit is formed at the control terminal; at least two synchronously triggered melting parts (101) and second fusible parts (102) are respectively formed on the fusible alloy (407). The FUSE is connected in parallel with the fusible alloy (407).

2. The patch-type thermal cutoff fuse according to claim 1, wherein It also includes a housing (404), the three-terminal fuse body (200) and the FUSE are located inside the housing (404).

3. The patch-type three-terminal fuse as described in claim 1 or 2, characterized in that, The fusible alloy (407) has a sheet-like structure with uniform thickness; The heating area (4083) of the heating element (408) is arranged in the middle of the fusible alloy (407), so that the fusible alloy (407) extends from the middle to both ends and forms a first fusible part (101) and a second fusible part (102), and the first fusible part (101) and the second fusible part (102) are triggered to melt simultaneously.

4. The patch-type thermal cutoff fuse of claim 1, wherein The FUSE includes a first FUSE (301) and a second FUSE (302); The first FUSE (301) and the second FUSE (302) are connected in series and then in parallel at both ends of the fusible alloy (407).

5. The patch-type three-terminal fuse as described in claim 1, characterized in that, Also includes PCB board (100); The three-terminal fuse body (200) and the FUSE are respectively disposed on the PCB board (100); The PCB board (100) is provided with traces of the main circuit (1) and traces of the parallel branch circuit, so that the FUSE is connected in parallel to both ends of the main circuit (1) of the three-terminal fuse body (200).

6. The patch-type three-terminal fuse as described in claim 3, characterized in that, The heating element (408) has a first electrode plate (4081) and a second electrode plate (4082) at its two ends for connecting to an external circuit, so that the first electrode plate (4081) and the second electrode plate (4082) respectively form a first connection end (P1) and a second connection end (P2). The heating zone (4083) is centrally located below the fusible alloy (407), and the heating zone (4083) forms the third connection end (P3). The two ends of the fusible alloy (407) are connected to the first electrode plate (4081) and the second electrode plate (4082) respectively, and the middle part is in contact with the heating area (4083). The heat generated by the heating area (4083) is uniformly conducted from the middle part of the fusible alloy (407) to its two ends, so that the regions extending from the middle part of the fusible alloy (407) to its two ends are respectively formed with a first fusible part (101) and a second fusible part (102).

7. The surface mount three-terminal fuse as described in claim 2, characterized in that, It also includes two bridging electrodes (406); the housing (404) has an opening at the top and a partition plate (4043) inside, which divides the inner cavity into a receiving groove and a bottom groove (4042). The fusible alloy (407) and the heating element (408) are arranged in the bottom groove (4042) of the housing (404), and the FUSE is disposed in the receiving groove; the partition plate (4043) of the housing (404) is provided with a through hole for the bridging electrode (406) to pass through, so that the bridging electrode (406) passes through the partition plate (4043) of the housing (404) from below into its receiving groove; The bottom of the two bridging electrodes (406) is connected to the main circuit (1), and their tops are respectively connected to the two ends of the FUSE.

8. The patch-type thermal cutoff fuse according to claim 7, wherein It also includes a positioning block (403) installed in the receiving groove; The FUSE is a fuse (402); the two ends of the positioning block (403) are respectively provided with a first slot (4033) and a second slot (4034), and the middle section (4032) is provided with a number of slots (4035) at intervals, so that the fuse (402) is spirally wound around the outer periphery of the positioning block (403), and its two ends are respectively fixed at the first slot (4033) and the second slot (4034).

9. The patch-type thermal cutoff fuse according to claim 8, wherein The two end regions (4031) of the positioning block (403) are conductive regions, and the middle section region (4032) is an insulating region; the first slot (4033) and the second slot (4034) are located in the two conductive regions respectively; the two end regions (4031) of the positioning block (403) are respectively provided with openings (4036) for the bridging electrodes (406) to pass through, so that the two bridging electrodes (406) are electrically connected to the two ends of the fuse (402) at the first slot (4033) and the second slot (4034) respectively. And / or, the inner wall of the receiving groove is provided with an inwardly protruding stepped protrusion (4041), and the positioning block (403) is mounted on the stepped structure of the protrusion (4041).

10. The patch-type thermal cutoff fuse according to claim 9, wherein An arc-extinguishing chamber (404a) is formed within the receiving groove, and the arc-extinguishing chamber (404a) is filled with arc-extinguishing material or sealing material; And / or, the surface of the fusible alloy (407) is coated with a fusing agent (405).

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