Fuse body cutting structure of a fuse

Abstract

The application relates to the field of circuit protection, and discloses a fuse body cutting structure of a fuse, at least one set of clamping components is arranged on the fuse body, and the clamping components are located in displacement channels; the clamping components and the displacement channels where the clamping components are located are in a slit structure, at least one through hole penetrating through opposite sides of the clamping components is arranged on the clamping components, and the through hole is connected with the slit structures on the two sides of the clamping components. The application can effectively reduce arc pressure and prevent the shell from cracking.

Description

Technical Field

[0001] This invention relates to the fields of power control and electric vehicles, specifically to the fuse element cutting structure for circuit protection. Background Technology

[0002] The protection principle of a fuse is as follows: Traditional fuses break the circuit by melting the fusible element, thus protecting the circuit; this is a passive disconnection method. Another type, developed in recent years, is the excitation fuse, which actively disconnects the fusible element using a driving device. Its structure mainly includes a driving device and a fusible element housed within the casing. When a fault current occurs, the driving device activates, actively disconnecting the fusible element and thus protecting the circuit. The driving device generally includes a gas generator and a piston structure. The generated high-pressure gas drives the piston structure to actively disconnect the fusible element. When disconnecting the fusible element, if the fault current is large and the disconnection point is a slit structure (see the structure of the push rod and guide rod on the parallel fusible element and the casing disclosed in Chinese Patent No. 202022971233X), a large electric arc will be generated at the disconnection point, resulting in high arc pressure. Because the disconnection point is a slit structure, the arc pressure may cause the casing to crack. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a melt cutting structure that can improve the product's breaking ability, prevent shell cracking, and improve product safety performance during melt cutting.

[0004] To solve the above-mentioned technical problems, the present invention provides a fuse element cutting structure, including a housing, a fusible element, and a driving device. The structure is characterized in that at least one set of clamping assemblies is provided on the fusible element, the clamping assemblies being located within a displacement channel; the clamping assemblies and the displacement channel are connected in a slit structure; at least one through hole is provided on the clamping assemblies, penetrating opposite sides of the clamping assemblies, and / or at least one conductive rod is embedded in the clamping assemblies; the through hole or conductive rod connects the slit structure on both sides of the clamping assemblies.

[0005] Preferably, the through hole is filled with a breathable conductive rod, or a solid conductive rod with a gap between it and the through hole for gas to pass through, or a porous structure for a coolable electric arc to pass through.

[0006] Preferably, the breathable conductive rod is made of metal wire mesh wound or pressed.

[0007] Preferably, the porous structure is porous ceramic.

[0008] Preferably, at least one end of the conductive rod inserted into the through hole is located inside one end of the through hole, and a distance is maintained between it and the end of the through hole.

[0009] Preferably, the outer periphery of the clamping assembly and the displacement channel therein form a slit structure, and the through hole connects to the slit structure.

[0010] Preferably, a limiting structure is provided between the clamping assembly and the displacement channel.

[0011] Preferably, the driving device can extend into the displacement channel to drive the clamping assembly.

[0012] Preferably, the displacement channel is connected to the outside; one end of the displacement channel connected to the outside is provided with a variable cross-section structure, and during the displacement of the clamping component, the fit relationship between the clamping component and the variable cross-section structure is successively clearance fit, close fit, and interference fit.

[0013] The melt cutting structure of the present invention, by opening a through hole in the clamping assembly, allows the generated arc gas to enter the through hole in the clamping assembly along the slit structure after the melt is cut. The arc gas pressure is instantly and significantly reduced through the through hole. At the same time, the opened through hole forms an arc path in parallel with the melt being cut. The parallel arc path can delay the melt cutting time to a certain extent, reduce the arc energy at the melt fracture slit, and the arc can be fully absorbed in the arc extinguishing medium, thereby improving the breaking capacity of the product. It can also reduce the arc voltage at the moment of melt breaking and effectively suppress overvoltage at the fracture.

[0014] A breathable conductive rod is installed in the through hole, or a solid conductive rod with a gap between the through hole and the gas passage is provided, or a conductive rod is embedded in the clamping assembly. After the melt is cut off, the conductive rod forms a conductive path in parallel with the cut melt under the action of the electric arc. The parallel conductive path can more effectively delay the cutting time of the melt, significantly reduce the arc energy at the slit of the melt fracture, and the arc can be fully absorbed in the arc extinguishing medium, thereby improving the breaking capacity of the product. At the same time, it can reduce the arc voltage at the moment of melt breakage and effectively suppress the overvoltage at the fracture.

[0015] By placing porous ceramics in the through-hole, the electric arc can be cooled while the voltage is reduced.

[0016] The displacement channel is configured to be connected to the outside. When the drive device drives the clamping assembly to break the melt, a certain displacement is required during the breaking process. After the melt is broken, the clamping assembly will quickly block the end of the displacement channel connected to the outside due to the very fast displacement speed of the clamping assembly. Only a small amount of electric arc will leak to the outside through the displacement channel, which will not affect the safety performance. With the safety performance satisfied, the displacement channel is configured to be connected to the outside to prevent the end of the displacement channel adjacent to the outside from bursting under the action of electric arc pressure.

[0017] In summary, the fuse using the melt cutting device of the present invention improves the safety performance of the product. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external structure of the melt cutting structure.

[0019] Figure 2 yes Figure 1 A schematic diagram of the AA cross-sectional structure.

[0020] Figure 3 This is a three-dimensional structural diagram of the clamping component.

[0021] Figure 4 This is a schematic diagram of the structure in which the through hole in the pusher block is filled with a medium.

[0022] Figure 5 This is a schematic diagram of the structure when the clamping component is interference-fitted with the displacement channel after the melt is broken.

[0023] Reference numerals: housing 10, displacement channel 11, variable cross-section structure 111, melt 20, connecting terminal 21, clamping assembly 30, push block 31, through hole 311, filling medium 312, limiting post 313, guide block 32. Detailed Implementation

[0024] Regarding the above technical solutions, preferred embodiments are now described in detail with reference to the figures.

[0025] See Figure 1 and Figure 2 The device includes a housing 10 made of insulating material. A displacement channel 11 is provided in the housing, with both ends of the channel open to the outside. One end is connected to the outside, and the other end allows the drive device to enter. A variable cross-section structure 111 is provided at the end of the displacement channel 11 that is connected to the outside. The longitudinal section of the variable cross-section structure is V-shaped.

[0026] The molten material 20 passes through the housing 10 and the displacement channel 11. One end of the connecting terminal 21 passes through the housing 10 and is electrically connected to the molten material 20. The cavity of the housing 10 through which the molten material 20 passes is filled with an arc-extinguishing medium. A positioning device for positioning the molten material 20 is provided on the housing 10. For example, a positioning post is used, and the molten material passes through the positioning post to limit its position.

[0027] A clamping assembly 30, made of insulating material, is disposed on the melt 20 located in the displacement channel 11. The clamping assembly 30 includes a pusher block 31 and a guide block 32 clamped on the melt 20. The clamping assembly 30 and the displacement channel 11 are in clearance fit, forming a slit structure between the clamping assembly and the displacement channel. Depending on the width of the slit structure, sealing devices are selectively provided at both ends of the slit structure to prevent the arc-extinguishing medium filling the shell cavity from entering the slit structure and leaking out of it.

[0028] The pusher block 31 and guide block 32 clamp the melt 20 within a concave-convex fit structure. This fit fixes the positions of the pusher block and guide block, preventing slippage on the melt. To better secure the melt within the clamping assembly, the pusher block has a limiting post 313 that passes through the melt 20 and enters a limiting hole on the guide block, preventing the melt from shifting relative to the clamping assembly. Limiting blocks (not shown) are located on opposite sides of the guide block. During assembly, these limiting blocks can engage with the grooves on both sides of the displacement channel, forming a limiting structure to initially position the clamping assembly.

[0029] See Figure 2 and Figure 3 A through hole 311 is formed on the push block 31, extending through both sides of the push block 31 and connecting the slit structures on opposite sides of the push block 31. The number of through holes 311 can be set as needed; when there are two or more through holes, they can be spaced apart or arranged crosswise. Figure 2 and Figure 3 In this design, the through holes 311 are located on both sides of the push block 31, with the shortest distance between them, resulting in the smallest volume within the through holes for the same inner diameter. When a larger pressure reduction is required, the through holes can be designed as oblique holes that are not perpendicular to the sides of the protrusion, provided that the strength of the push block 31 is satisfied. The oblique holes lengthen the through holes, thereby increasing the volume within the through holes for the same inner diameter, and better reducing the gas pressure generated by the electric arc.

[0030] In this embodiment, the through hole is formed on the push block 31, or it can be formed on the guide block 32, or through holes can be formed on both the push block 31 and the guide block 32.

[0031] The through-hole 311 can be filled with a filling medium 312 that allows gas to pass through, as needed. See also Figure 4The filling medium 312 can cool the electric arc and play an auxiliary role in extinguishing the arc. The filling medium can be a breathable conductive rod that allows gas to pass through, a solid conductive rod, or an insulating porous structure.

[0032] The breathable conductive rod can be a rod-shaped structure formed by winding or pressing metal wire mesh, matching the inner diameter of the through hole, or it can be a porous conductive rod formed by processes such as hollowing. When inserted into the through hole, it allows arc gas to pass through and can also cool the arc.

[0033] When the conductive rod inserted into the through hole is solid, a gap must be maintained between the conductive rod and the through hole to allow gas to pass through. For solid conductive rods, since their inner diameter is smaller than that of the through hole, the conductive rod can be fixed in the through hole with adhesive during filling. Alternatively, the length of the conductive rod can be shorter than that of the through hole, and the conductive rod can be inserted into the through hole, with insulating plugs with through holes at both ends of the through hole used for sealing and fixing.

[0034] Whether it is a perforated conductive rod or a solid conductive rod, when it is in a filled through hole, at least one end is preferably located inside the through hole. The purpose is to lengthen the distance from the melt fracture surface and improve the insulation resistance after breakage.

[0035] The insulating porous structure can be a porous ceramic rod, or a porous structure made of other insulating materials. The insulating porous structure can cool the electric arc.

[0036] Regardless of whether it is a porous conductive rod, a solid conductive rod, or a porous ceramic rod, it can be fixed in the through hole by adhesive or by sealing it with an insulating plug with vent holes. When it is a porous conductive rod or a porous ceramic rod, it can also be fixed in the through hole by close contact.

[0037] When the through hole 311 is set, the arc gas generated after the melt breaks will pass through the through hole along the slit structure, increasing the space volume of the arc gas and rapidly reducing the gas pressure generated by the arc gas.

[0038] By filling the through holes with conductive rods, the electric arc passing through the through holes can form a conductive path. When there are multiple through holes and they are spaced apart, multiple parallel conductive paths will be formed. The parallel conductive paths can significantly reduce the arc voltage at the moment the melt breaks, suppressing overvoltage. At the same time, it can significantly reduce the arc energy at the slit of the melt fracture, and the arc can be fully absorbed in the arc-extinguishing medium.

[0039] Alternatively, at least one conductive rod can be embedded in the clamping assembly to connect the slit structures on both sides. When the melt breaks, the generated electric arc creates a conductive path at the conductive rod, which is equivalent to connecting a conductive path in parallel with the original melt. The conductive path can effectively delay the breaking time of the melt, reduce the energy at the break point, make the breaking more reliable, and effectively suppress overvoltage.

[0040] Alternatively, through holes can be made in the clamping assembly and conductive rods can be embedded in it.

[0041] When the clamping component 30 shifts and breaks the melt 20, the guide block 32 of the clamping component 30 and the variable cross-section structure of the displacement channel 11 change from a clearance fit to a tight fit and finally to an interference fit as the clamping component 30 shifts until it reaches the dead point. This seals the end of the displacement channel that is connected to the outside. (See [reference]). Figure 5 .

[0042] One end of the displacement channel is designed to connect to the outside. Due to the high displacement speed of the clamping component and the short distance between the clamping component and the variable cross-section structure, the clamping component will quickly block the displacement channel after the molten material is broken by it. Therefore, only a small amount of electric arc will overflow from the end of the displacement channel connected to the outside, posing no safety hazard. Simultaneously, because the displacement channel is connected to the outside, after the clamping component breaks the molten material, the gas pressure generated by the electric arc will rapidly decrease under the combined action of the through-hole in the clamping component and the end of the displacement channel connected to the outside, avoiding the safety hazard of product shell cracking and explosion.

[0043] exist Figure 2 and Figure 3 In the process, the clamping components are in one group. Depending on the actual needs, multiple groups of clamping components can be set. When there are two or more groups of clamping components, each group of clamping components is located in its own displacement channel. When the melt is disconnected, multiple breaks will be formed on the melt.

[0044] The above-mentioned melt cutting structure is explained in conjunction with the driving device. The driving device includes a gas generator and a piston structure. The impact end of the piston structure enters the displacement channel, driving the clamping assembly 30 within the displacement channel. When the gas generator receives an excitation signal, it releases high-pressure gas and then drives the piston structure to displace into the displacement channel, driving the clamping assembly 30 to overcome the limiting structure. During the displacement process, the clamping assembly 30 pulls the melt 20 apart and then moves to the variable cross-section structure at the end of the displacement channel that connects to the outside, where it seals the displacement channel. During this process, the electric arc generated after the melt breaks passes through the through hole of the clamping assembly along the slit structure, releasing the gas pressure generated by the arc and rapidly reducing the arc pressure. This also avoids the possibility of arc sustaining at the melt break. Furthermore, the through hole is filled with an auxiliary arc-extinguishing medium, which quickly extinguishes the generated arc. During this process, only a small portion of the arc overflows to the outside, but this does not pose any safety risk.

[0045] When there are two or more through holes spaced apart, the electric arc generated by the melt breaking passes through the through holes respectively, forming a parallel electric arc path. The parallel electric arc path can significantly reduce the arc voltage at the moment of melt breaking and suppress overvoltage; at the same time, it can significantly reduce the arc energy at the slit of the melt fracture, and the arc can be fully absorbed in the arc extinguishing medium.

[0046] In practical applications, the melt cutting structure can be used not only to cut melts that are electrically connected to an external circuit, but also to cut melts connected in parallel to melts that are electrically connected to an external circuit.

[0047] As can be seen from the above, the present invention reduces the arc pressure and arc voltage by opening through holes in the clamping component; in order to further reduce the arc pressure, the displacement channel is connected to the outside, which can further release the arc pressure, so that the product can completely avoid the safety accident of cracking or exploding of the product shell due to the large arc pressure when the melt breaks, thus improving the safety and reliability of the product.

Claims

1. A fuse element cutting structure, comprising a housing, a fusible element, and a driving device, characterized in that, At least one set of clamping components is provided on the melt, and the clamping components are located in the displacement channel; the clamping components and the displacement channel are in a slit structure, and at least one through hole is provided on the clamping components to pass through the opposite sides of the clamping components, or / and at least one conductive rod is embedded in the clamping components; the through hole or conductive rod connects the slit structure on both sides of the clamping components.

2. The fuse element cutting structure according to claim 1, characterized in that, The through hole is filled with a breathable conductive rod, or a solid conductive rod with a gap between it and the through hole for gas to pass through, or a porous structure that allows gas to pass through and can cool an electric arc.

3. The fuse element cutting structure according to claim 2, characterized in that, The breathable conductive rod is made by winding or pressing metal wire mesh.

4. The fuse element cutting structure according to claim 2, characterized in that, The porous structure is porous ceramic.

5. The fuse element cutting structure according to claim 2, characterized in that, At least one end of the conductive rod inserted into the through hole is located inside one end of the through hole, and a distance is maintained between it and the end of the through hole.

6. The fuse element cutting structure according to claim 1, characterized in that, Sealing devices are provided at both ends of the slit structure.

7. The fuse element cutting structure according to claim 1, characterized in that, A limiting structure is provided between the clamping assembly and the displacement channel.

8. The fuse element cutting structure according to claim 1, characterized in that, The drive device can penetrate the displacement channel to drive the clamping assembly.

9. The fuse element cutting structure according to any one of claims 1 to 8, characterized in that, The displacement channel is connected to the outside; a variable cross-section structure is provided at one end of the displacement channel connected to the outside. During the displacement of the clamping component, the fit between the clamping component and the variable cross-section structure is successively clearance fit, close fit, and interference fit.

Images