Fuse and method of manufacturing the same

Abstract

The application provides a fuse and a manufacturing method thereof, and belongs to the technical field of fuses. In order to solve the problem of low filling density of the fuse filler, the application provides the fuse and the manufacturing method thereof. The fuse comprises a pipe body, the pipe body has two opposite ports, the two ports of the pipe body are provided with end caps, and a fuse cavity is formed in the pipe body; a filler is filled in the fuse cavity and is used for arc extinguishing; at least one port of the pipe body is provided as a filling port and is used for filling the filler; a fuse part is arranged in the fuse cavity; and a pre-tightening layer covers at least part of the inner surface of the fuse cavity. The pre-tightening layer extrudes the filler and can expand towards the fuse part or further compress away from the fuse part. The application extrudes the filler through the pre-tightening layer, improves the filling density of the filler, and thus improves the breaking capacity of the fuse.

Description

Technical Field

[0001] This application relates to the field of fuse technology, and more particularly to fuses and methods of manufacturing them. Background Technology

[0002] With the development of science and technology and the increasing awareness of environmental protection, the new energy revolution is an inevitable trend, especially in the new energy industry represented by electric vehicles and energy storage, which places increasingly higher demands on fuses. Firstly, there's the voltage. Traditional fuses only require 250V for general applications, but new energy sources are demanding higher voltages for greater efficiency. For example, electric vehicles have increased from 380V to 800V, but the fuse size cannot be increased, which adds new requirements for arc extinguishing. Secondly, there's the issue of sealing. Vehicles operate in complex environments; poor sealing allows moisture, salt spray, and corrosive gases to enter, affecting fuse lifespan and, in severe cases, electrical performance.

[0003] Traditional fuses typically consist of a glass / ceramic tube with a fuse wire running through the middle, and some products also have filler material in the middle. Both ends are fitted with end caps. The end caps are in direct, hard contact with the ceramic / glass tube, resulting in poor sealing and allowing water vapor to seep directly into the fuse wire. At the same time, the filler material cannot be compacted. After filling, the end caps are pressed on directly, and the bottom of the caps is flat, which is also the same as the plane of the filler material, so it is impossible to compact them, thus limiting the improvement of breaking capacity.

[0004] In response to the above problems, there are corresponding improvements in the existing technology. For example, Chinese patent application with publication date of 2022-11-01 and publication number CN115274375A clearly points out that traditional fuses cannot guarantee the filling density when filled with quartz sand. Therefore, a certain filling density is achieved by making the filler into a mixed slurry and then removing the solvent through multiple baking processes. The shortcomings of this solution are: 1. The filler mixture contains a large amount of solvent (alcohol, resin, etc.), which, when removed by baking, will form continuous channels extending from the inside and outside. These channels are also channels for subsequent arc propagation, which is detrimental to arc extinguishing, especially for high-voltage products, posing a safety hazard; 2. Air bubbles cannot be eliminated during the filling process, easily causing local voids and affecting arc extinguishing. Specifically, when filling fuses with filler, one end needs to be sealed first, and then filled from the other end. Generally, fuses are of long-to-long-to-wide aspect ratio, such as 6*32mm tubular shapes. If honey is poured into a glass bottle, a large number of air bubbles will appear. Since the solid content of the filler is over 70%, its density is much higher than that of honey, making it impossible to guarantee that there are no air bubbles in the mixture; 3. Low efficiency and high cost, i.e., mixing materials first, then filling, then standing for 72 hours, and finally multiple rounds of baking.

[0005] For example, Chinese patent application CN215266173U, published on December 21, 2021, uses a method of making a small hole in the fuse housing and then sealing it with a plug to ensure reliability in order to guarantee filling density. The shortcomings of this method are: 1. The density of the filling cannot be guaranteed. Filling a cavity with a small opening and a large interior is inconvenient, and there is no clear standard for whether it is full. It is not easy to observe visually. If a certain filling density cannot be achieved, its arc-extinguishing ability will be significantly reduced. Furthermore, if a mixed slurry is used for filling, the problem of air bubbles cannot be solved; 2. After making a hole in the housing, its overall strength is significantly reduced, especially at the location of the hole, which is not conducive to pressure resistance during breaking and actually affects the breaking capacity. Specifically, when the fuse breaks, the fuse vaporizes, and the arc can reach thousands or even hundreds of thousands of degrees Celsius. The air pressure inside the housing expands tens or even thousands of times, which may cause the plug at the hole to be ejected or even the housing to shatter; 3. The sealing at the plug hole cannot be guaranteed. There is no clamping device above the plug, which may loosen under high-frequency vibration. Summary of the Invention

[0006] The purpose of this application is to address the problem of low filler density in existing fuses. Therefore, this application provides a fuse and a method for manufacturing the same, which improves the filler density by compressing the filler with a pre-tightening layer, thereby increasing the fuse's breaking capacity.

[0007] This application provides a fuse, including a tube body with two opposing ports. The two ports of the tube body are provided with end caps, and a fuse cavity is formed within the tube body.

[0008] A filler material is used to fill the fuse cavity and to extinguish the arc.

[0009] At least one of the ports of the tube is configured as a filling port and is used to fill the filler.

[0010] A fusible portion is disposed within the fusible cavity;

[0011] A pre-tightening layer covers at least a portion of the inner surface of the fuse cavity. The pre-tightening layer compresses the filler and can expand toward the fuse portion or be further compressed away from the fuse portion.

[0012] By employing the above technical solution, the filling density of the filler is increased by compressing it with the pre-tightening layer, thereby improving the breaking capacity of the fuse. Furthermore, the pre-tightening layer can be further compressed, thus providing space for the volume expansion within the fuse cavity during melting, reducing the possibility of pre-tightening layer damage, and achieving springback after the expanded volume shrinks. At the same time, the springback of the pre-tightening layer can push the filler that moves outward during melting to move in the opposite direction, that is, spring back to the melting point of the fuse section, thereby improving the arc extinguishing capability and thus improving the breaking capacity.

[0013] In some embodiments, the filler includes an arc-quenching filler and a gas-generating filler, wherein the arc-quenching filler is configured as solid particulate matter, the gas-generating filler can be thermally decomposed to generate gas, and the gas-generating filler occupies less than 10% of the volume of the filler.

[0014] By incorporating gas-generating filler into the conventionally set arc-extinguishing filler, the amount of gas generated during the breaking process is increased, thereby further enhancing the pre-tightening layer's rebound arc-extinguishing capability and improving the breaking capacity. Furthermore, by limiting the ratio of arc-extinguishing filler to gas-generating filler, excessive gas volume can be prevented from causing the fuse to explode, insufficient arc-extinguishing filler within the limited volume of the fuse cavity can be avoided from affecting the arc-extinguishing effect, and proper rebound of the pre-tightening layer onto the arc-extinguishing filler ensures the rebound filler fills the fuse area, guaranteeing the arc-extinguishing effect. Simultaneously, the improved fluidity of the solid particles enhances the efficiency and compactness of the arc-extinguishing filler's rebound to the fuse area, further improving the breaking capacity.

[0015] In some embodiments, the particle size of the arc-quenching filler in the filler is set to 20-1000 mesh, and the material of the tube body is red steel paper fiber, melamine, ceramic, organic matter or glass.

[0016] In some embodiments, the arc-quenching filler includes quartz sand, and the gas-generating filler includes at least one of melamine, magnesium hydroxide, aluminum hydroxide, and ammonium salts.

[0017] In some embodiments, the filling amount of the filler and the compression ratio of the preload layer satisfy the following:

[0018] H / (V-V1)<P<H / (V-V0),

[0019] Wherein, H is the weight of the filler, V is the volume of the fuse cavity, V0 is the volume of the pre-tightening layer in its uncompressed state, V1 is the volume of the pre-tightening layer in its maximum compressed state, and P is the filling density of the filler.

[0020] The compression ratio of the pre-tightening layer is set to be no less than 5%.

[0021] In some embodiments, the thickness of the pre-tightening layer accounts for 3-30% of the thickness of the fuse cavity.

[0022] In some embodiments, the fusible part is a fusible wire, and the tube body is configured as a round tube or a square tube of equal diameter.

[0023] In some embodiments, the pre-tightening layer can withstand reflow soldering at 260°C.

[0024] In some embodiments, the pre-tightening layer is made of polyurethane, silicone, rubber, or plastic.

[0025] This application embodiment also provides a method for manufacturing any of the above-described fuses, including:

[0026] When the pre-tightening layer covers the inner surface of the fuse cavity corresponding to the end cap, the method includes:

[0027] Insert the fused section into the tube body;

[0028] A pre-tightening layer is inserted into one end of the tube, and the end cap of the corresponding end is pressed onto the pre-tightening layer to seal the end. The other end of the tube is the filling port.

[0029] The filler is filled through the filling port, which compresses the pre-tightening layer at one end.

[0030] Another pre-tightening layer is inserted into the filling port of the tube, and the end cap of the corresponding end is pressed onto the pre-tightening layer to seal the filling port, forming a fusion cavity. The two pre-tightening layers are squeezed to a preset compression amount and can expand toward the fusion part or be further compressed away from the fusion part.

[0031] When the pre-tightening layer covers the inner surface of the tube corresponding to the fuse cavity, the method includes:

[0032] The pre-tightening layer is inserted into the corresponding position inside the tube, or a pre-tightening layer is formed by bonding the pre-tightening layer to the corresponding position inside the tube using a pre-tightening layer forming solution.

[0033] Insert the fused section into the tube body;

[0034] The end cap is installed at one end of the tube body, and the other end is a filling port. After the filler is filled through the filling port, the end cap at the other end is installed, forming a fusible cavity. This allows the pre-tightening layer to be squeezed to a preset compression amount, and it can expand toward the fusible part or be further compressed away from the fusible part.

[0035] The above technical solution is easy to manufacture, and the filling density of the filler is increased by extruding the filler through the pre-tightening layer, thereby improving the breaking capacity of the fuse.

[0036] Other features and corresponding beneficial effects of this application will be described in the latter part of the specification, and it should be understood that at least some of the beneficial effects will become obvious from the description in this application. Attached Figure Description

[0037] Figure 1(a) is a schematic diagram of a fuse structure with a double-ended preload layer according to this application;

[0038] Figure 1(b) is a schematic diagram of the state of the fuse in Figure 1(a) during rapid melting;

[0039] Figure 1(c) is a schematic diagram of the state when the pre-tightening layer of the fuse in Figure 1(a) rebounds;

[0040] Figure 2(a) is a schematic diagram of another fuse with a double-ended preload layer according to this application;

[0041] Figure 2(b) is a schematic diagram of the structure of the fuse with a single-end preload layer of this application;

[0042] Figure 3(a) is a schematic diagram of the structure of the fuse with double preload layer of this application;

[0043] Figure 3(b) is a schematic diagram of the structure of the fuse with a single pre-tightening layer according to this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] Hats 101 and 102;

[0046] Pre-tightening layers 201 and 202;

[0047] Fusible section 300; tube body 400; filler 500. Detailed Implementation

[0048] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details will be included in the following description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0049] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" 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. Therefore, features defined with "first," "second," etc., 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. Unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0051] It should be noted that current fuses typically use quartz sand or similar fillers to improve breaking capacity. If the filler is too sparse, resulting in large pores, it is easy for an electric arc to form. The arc voltage can damage downstream protection circuits. Furthermore, sparse filler is not conducive to normal heat dissipation of the fuse element, which also affects breaking capacity. Therefore, current fuses strive for dense filling, and even mixed slurry fillers have been developed. These can completely fill the fuse cavity in liquid form (after being dried into a solid state) to block the arc and achieve rapid arc extinguishing. However, on the one hand, the cost of mixed slurry fillers is relatively high, and as mentioned in the background art, there are still many problems. On the other hand, mixed slurry fillers are usually used in high-specification fuses that require large-diameter fuse wires. Since the mixed slurry filler directly extinguishes the arc through the filler, in order to ensure breaking capacity, such fuses usually need to split the large-diameter fuse (usually a fuse wire) into multiple small-diameter fuses connected in parallel, which further increases the processing cost. At the same time, this method is difficult to guarantee the consistency of multiple small-diameter fuses, which can easily lead to uneven current distribution, some fuses failing to disconnect in time, resulting in circuit overload, or some fuses exceeding their breaking capacity, resulting in the arc not being effectively extinguished, and so on.

[0052] However, as the demand for breaking capacity increases, dense fillers cannot further increase the breaking capacity. Instead, the thickness and volume of the granular filler must be increased to ensure arc extinguishing capability.

[0053] Please refer to Figures 1(a), 2(a), 2(b), 3(a), and 3(b). Figure 1(a) is a schematic diagram of a fuse structure with double-ended pre-tightening layers 201 and 202 according to this application. Figure 2(a) is a schematic diagram of another fuse structure with double-ended pre-tightening layers 201 and 202 according to this application. The difference between this fuse and Figure 1(a) is the different way in which the fuse portion 300 passes through the pre-tightening layers 201 and 202 and contacts the end caps 101 and 102. Figure 2(b) is a schematic diagram of a fuse structure with a single-ended pre-tightening layer according to this application. Figure 3(a) is a schematic diagram of a fuse structure with double-layer pre-tightening layers 201 and 202 according to this application. Figure 3(b) is a schematic diagram of a fuse structure with a single-layer pre-tightening layer according to this application.

[0054] This application provides a fuse, including a tube body 400, a filler 500, a fusible part 300, and a pre-tightening layer.

[0055] The tube body 400 has two opposite ports, and the two ports of the tube body 400 are provided with end caps 101 and 102, and a fusible cavity is formed inside the tube body 400.

[0056] The filler 500 is filled into the fuse cavity and is used for arc extinguishing.

[0057] At least one port of the tube body 400 is configured as a filling port and is used to fill the filler 500.

[0058] The fusible part 300 is inserted into the fusible cavity. The fusible part 300 can be in the form of a sheet, a wire, or other shapes.

[0059] The pre-tightening layers 201 and 202 at least cover a portion of the inner surface of the fuse cavity. For example, the pre-tightening layers can be double-layered or single-layered, can be left-right, top-bottom, or can completely wrap around the tube body 400, or wrap around the tube body 400 and the end caps, etc. Preferably, the pre-tightening layers 201 and 202 cover the inner surfaces of the two corresponding end caps 101 and 102 of the fuse cavity, thereby improving the sealing between the tube body 400 port and the end caps 101 and 102, thus improving the sealing performance of the fuse, protecting the internal fuse part 300 from the influence of the external environment, making it suitable for harsh environments, and relatively simple to manufacture.

[0060] This fuse increases the filling density of the filler 500 by compressing it with pre-tightening layers 201 and 202, thereby improving the fuse's breaking capacity. Furthermore, this compaction method is low-cost; simply adding pre-tightening layers 201 and 202 to the outside of the conventional filler 500 significantly improves the arc-extinguishing effect and breaking capacity.

[0061] Please refer to Figures 1(b) and 1(c). Figure 1(b) is a schematic diagram of the state of the fuse in Figure 1(a) when it melts rapidly; Figure 1(c) is a schematic diagram of the state of the pre-tightening layers 201 and 202 of the fuse in Figure 1(a) when they rebound.

[0062] It should be noted that an excessively dense filler 500 results in an excessively low porosity, which prevents the plasma generated during the melting process from fully penetrating into the filler 500, thus preventing the filler 500 from fully exerting its breaking capacity.

[0063] Therefore, in one embodiment, the pre-tightening layers 201 and 202 can expand toward the fusible portion 300 or be further compressed away from the fusible portion 300. Specifically, the pre-tightening layers 201 and 202 are further compressed away from the fusible portion 300, thereby providing space for the volume expansion within the fusible cavity during fusing, increasing the pores between the fillers 500, so that the plasma gas generated by the fuse fusing can quickly and fully diffuse into the pores of the fillers 500 and contact them for heat dissipation. At this time, the rebound force of the pre-tightening layers 201 and 202 is enhanced, and they can expand rapidly toward the fusible portion 300, that is, they rebound after the expanded volume shrinks, thereby pushing the fillers 500 to re-compact, causing the fillers 500 to squeeze the plasma gas in the pores, greatly enhancing the arc-extinguishing ability of the fillers 500, and thus improving the breaking capacity.

[0064] It should be noted that when the fuse section 300 breaks, it vaporizes (i.e., at position 330, and in an expanded state A1), generating high temperature. The pressure within the fuse space increases, compressing the pre-tightening layers 201 and 202. When the vaporized material of the fuse section 300 comes into contact with the filler 500 and cools (i.e., in a contracted state B1), the temperature drops, and the pre-tightening layers 201 and 202 rebound, carrying the filler 500 back to the arc-starting area, extinguishing the arc. This process typically occurs on the order of microseconds.

[0065] In one embodiment, the filler 500 includes an arc-quenching filler.

[0066] The arc-quenching filler can be one or more conventional arc-quenching fillers, such as quartz sand, ceramic materials, mica, etc., or a mixture of 500 mixed slurry fillers.

[0067] Preferably, the arc-extinguishing filler is made of solid particles. Solid particles have better flowability and better compatibility with the pre-tightening layers 201 and 202, which can improve the efficiency and compactness of the arc-extinguishing filler returning to the melting point, thereby further improving the breaking capacity. More preferably, the arc-extinguishing filler includes quartz sand, which is cost-controllable.

[0068] In one embodiment, the filler 500 further includes a gas-generating filler that can be heated to decompose and generate gas. That is, the gas-generating filler is mixed into the normally set arc-extinguishing filler, which increases the amount of gas generated during the breaking process, increases the force and speed of compression and rebound of the pre-tightening layers 201 and 202, thereby further improving the rebound arc-extinguishing capability of the pre-tightening layers 201 and 202 and improving the breaking capability.

[0069] Preferably, the gas-generating filler accounts for less than 10% of the volume of the filler 500, and more preferably 0.5%-3%.

[0070] This method, by limiting the ratio of arc-extinguishing filler and gas-generating filler, can prevent the fuse from bursting due to excessive gas production. It can also prevent insufficient arc-extinguishing filler in the limited volume of the fuse cavity from affecting the arc-extinguishing effect. Furthermore, it can ensure that the pre-tightening layers 201 and 202 properly rebound the arc-extinguishing filler so that the rebounded arc-extinguishing filler fills the fuse area, thus ensuring the arc-extinguishing effect.

[0071] In one embodiment, the particle size of the arc-quenching filler in the filler 500 is set to 20-1000 mesh. Furthermore, the coarser the fusing portion 300, the smaller the mesh size of the selected arc-quenching filler.

[0072] In one embodiment, the fusing part 300 is a fuse wire, and its material can be a low-melting-point fuse wire, such as a lead-tin alloy, depending on the different current requirements. Because its melting point is relatively low, around 200°C, it can quickly melt and break the circuit when the current is too high, protecting the circuit. This type of fuse wire has high sensitivity and is particularly suitable for low-current circuits, such as household appliances, and has good arc-extinguishing performance with minimal impact on the fuse. For circuits with high current requirements, such as industrial electrical equipment, high-melting-point fuse wires, such as those made of silver or copper, must be selected. These metals have high melting points, with silver reaching 960°C and copper reaching as high as 1080°C. They can withstand large currents, have excellent conductivity, low resistivity, and produce less metal vapor when melting, making it easier to extinguish the arc.

[0073] In one embodiment, the tube body 400 is configured as a round or square tube of equal diameter. Preferably, the diameter (width) of the tube body 400 is 2-13 mm and the length is 5-50 mm, in which case the diameter of the fused portion 300 is preferably less than 0.5 mm; if the diameter (width) of the tube body 400 is greater than 13 mm and the length is greater than 50 mm, in which case the diameter of the fused portion 300 is preferably greater than 1 mm.

[0074] In one embodiment, the tube body 400 is typically made of an insulating and heat-resistant material and meets certain mechanical strength requirements, such as red steel paper fiber, melamine, ceramics, organic materials, glass, etc.

[0075] In one embodiment, the gas-generating filler includes at least one of melamine, magnesium hydroxide, aluminum hydroxide, and ammonium salts to meet the requirements of high temperature resistance and prevent decomposition under normal operating heating conditions of the fuse.

[0076] In one embodiment, the filling amount of filler 500 and the compression ratio of pre-tightening layers 201 and 202 are satisfied to ensure that filler 500 is compacted:

[0077] H / (V-V1)<P<H / (V-V0),

[0078] Wherein, H is the weight of filler 500, V is the volume of the fuse cavity, V0 is the volume of pre-tightening layers 201 and 202 in the uncompressed state, V1 is the volume of pre-tightening layers 201 and 202 in the maximum compressed state, and P is the filling density of filler 500.

[0079] Preferably, the compression ratio of the pre-tightening layers 201 and 202 is set to not less than 5%, and more preferably 50-70%. It should be noted that this compression ratio refers to the compression ratio of the pre-tightening layers 201 and 202 under normal fuse conditions, i.e., before the fuse melts. Preferably, the higher the compression ratio of the pre-tightening layers, the greater the mechanical strength of the tube body and the smaller the particle size of the filler.

[0080] At the same time, if the compression ratio is too high, the space for further compression will be smaller and the space for expansion will be insufficient, resulting in extremely limited increase in the porosity of the arc-extinguishing filler and a weaker arc-extinguishing effect. On the other hand, if the compression ratio is too low, the space for further compression will be too large and the space for expansion will be too large, resulting in excessive porosity of the arc-extinguishing filler and an inability to compact the rebound, which also results in a weaker arc-extinguishing effect.

[0081] Furthermore, the greater the compression ratio of the pre-tightening layers 201 and 202, the greater the mechanical strength of the tube body 400, and the smaller the particle size of the filler 500.

[0082] In one embodiment, the pre-tightening layers 201 and 202 can withstand reflow soldering at 260°C and can still maintain their elasticity even after reflow soldering at 260°C.

[0083] In one embodiment, the pretensioning layers 201 and 202 are made of polyurethane, silicone, rubber, plastic, or elastic sheet.

[0084] In one embodiment, the pre-tightening layers 201 and 202 account for 3-30% of the thickness of the fuse cavity. Preferably, when the pre-tightening layers 201 or 202 are disposed at the ends, their thickness is greater than when disposed in the circumferential direction.

[0085] This application also provides a method for manufacturing a fuse, which is convenient to manufacture and improves the breaking capacity of the fuse by extruding the filler 500 through the pre-tightening layers 201 and 202.

[0086] In one embodiment, when the pre-tightening layers 201 and 202 cover the inner surfaces of the corresponding end caps 101 and / or 102 of the fuse cavity, it is preferable to prepare a fuse with double-ended pre-tightening layers 201 and 202 as shown in Figures 1(a) and 2(a), the preparation method including:

[0087] The fusible part 300 is inserted into the tube body 400.

[0088] A pre-tightening layer 201 is inserted into one end of the tube body 400, and the end cap 101 at the corresponding end is pressed onto the pre-tightening layer 201 to seal the end. The other end of the tube body 400 is a filling port.

[0089] Filler 500 is filled through the filling port, causing the pre-tightening layer 201 at one end to be compressed.

[0090] Another pre-tightening layer 202 is inserted into the filling port of the tube body 400, and the end cap 102 at the corresponding end is pressed onto the pre-tightening layer 202 to close the filling port and form a fusible cavity. The two pre-tightening layers 201 and 202 are squeezed to a preset compression amount and can expand toward the fusible part 300 or be further compressed away from the fusible part 300.

[0091] It is understandable that the fuse part 300 needs to avoid the pre-tightening layers 201 and 202 at both ends and connect to the external lead wire through the end caps 101 and 102. For example, as shown in Figure 1(a), it can pass directly through the middle of the pre-tightening layers 201 and 202, or as shown in Figure 2(a), it can pass through the edge of the pre-tightening layers 201 and 202.

[0092] This method improves the sealing performance of the fuse by assembling the pre-tightening layers 201 and 202 with the end caps 101 and 102.

[0093] In one embodiment, when the pre-tightening layers 201 and 202 cover the inner surface of the corresponding tube body 400 of the fuse cavity, it is preferable to prepare a fuse with double pre-tightening layers 201 and 202 as shown in FIG3(a), or to prepare a fuse with the pre-tightening layers fully covering the inner wall of the tube body 400 circumferentially. The preparation method includes:

[0094] The pre-tightening layers 201 and 202 are inserted into the corresponding positions inside the tube body 400, or the pre-tightening layers 201 and 202 are formed by bonding them together in the corresponding positions inside the tube body 400 using a pre-tightening layer forming solution.

[0095] The fusible part 300 is inserted into the tube body 400.

[0096] The end cap 101 of the tube body 400 is installed at one end, and the other end is a filling port. After the filler 500 is filled through the filling port, the end cap 102 of the other end is installed, forming a fusible cavity. This allows the pre-tightening layers 201 and 202 to be compressed to a preset compression amount, and they can expand toward the fusible part 300 or be further compressed away from the fusible part 300.

[0097] This method is simpler, requiring only the processing of the tube body 400 to attach a pre-tightening layer 201 and 202. Other processes are basically no different from those of traditional fuses, and it can make better use of existing mature equipment for mass production.

[0098] It is understandable that when the pre-tightening layer 201 and 202 are formed in the corresponding positions inside the tube 400 by the pre-tightening layer forming solution, the parts that do not need to be covered need to be protected to prevent them from being covered by the pre-tightening layer 201 and 202.

[0099] In other alternative embodiments, the fuse with pre-tightening layers 201 and 202 covering both the end and circumference of the tube body 400 can also be prepared in combination with the above methods.

[0100] In one embodiment, the tube body is made of ceramic and has a diameter of 10-40 mm and a length of 40-60 mm.

[0101] In one embodiment, the pre-tightening layer is made of silicone or mica, with a compression ratio of 50-70%.

[0102] Test the fuse of this application:

[0103] Example 1:

[0104] A ceramic tube with a diameter of 10mm and a length of 38mm is filled with 60-200 mesh quartz sand and an additional 5% magnesium hydroxide as the gas-generating substance. Both ends are pre-tightened with a 2.2mm thick silicone-based material with a compression ratio of 50%. The fuse is a 0.2mm diameter alloy wire, specification 10A, with a breaking capacity of 1000VDC1KA. Five tubes were tested and all of them worked normally.

[0105] Example 2:

[0106] Everything else is the same as in Example 1, except that:

[0107] The compression ratio was changed to a high-elasticity silicone with a compression ratio greater than 70% to replace the silicone pre-tightening layer with a compression ratio of 50%. Its breaking capacity is 1000VDC1KA. In the test of 5 pieces, 1 piece exploded, which shows a certain abnormality rate.

[0108] Example 3:

[0109] Everything else is the same as in Example 1, except that:

[0110] The compression ratio was changed to mica sheets with a compression ratio of less than 10% to replace the silicone pre-tightening layer with a compression ratio of 50%. Its breaking capacity was 1000VDC1KA. 5 pieces were tested, and 3 pieces exploded, which is a relatively high abnormality rate.

[0111] Comparative Example 1:

[0112] The rest is the same as in Example 1, except that the pre-tightening layer and gas filler are not provided.

[0113] Under the 1000VDC 1KA test requirement, all 5 particles exploded.

[0114] Example 4:

[0115] A ceramic tube with a diameter of 38mm and a length of 58mm is filled with 20-100 mesh quartz sand and an additional 2% magnesium hydroxide as a gas-generating substance. The ceramic tube wall is surrounded by a 2.0mm thick silicone-based pre-tightening layer with a compression ratio of 50%. The fuse is a 0.2mm thick alloy sheet with multiple variable clamps, which is equivalent to multiple fuses. The specification is 300A, and the breaking capacity is 800VDC20KA. Three fuses were tested and all of them worked normally.

[0116] Comparative Example 2:

[0117] The product dimensions are the same as in Example 1, but the filling material is a mixture of 20-100 quartz sand and water glass. After filling the ceramic tube, it is baked at 80 degrees for 24 hours to remove the moisture from the water glass. The breaking capacity is 800VDC20KA. Three tubes were tested, and two of them exploded.

[0118] Table 1:

[0119]

[0120] It is evident that the fuse in this application has superior performance.

[0121] 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 fuse, characterized in that, Includes a tube body having two opposing ports, with end caps provided at the two ports of the tube body, and a fusible cavity formed within the tube body; A filler material is used to fill the fuse cavity and to extinguish the arc. At least one of the ports of the tube is configured as a filling port and is used to fill the filler. A fusible portion is disposed within the fusible cavity; A pre-tightening layer, at least covering a portion of the inner surface of the fuse cavity; Under normal operating conditions, the pre-tightening layer applies compressive force to the filler to increase the filler density; When the fuse breaks, the pre-tightening layer can be further compressed away from the fuse due to the increased pressure inside the fuse cavity, so as to provide diffusion space for the plasma gas formed by the fuse melting; and after the pressure decreases, it expands towards the fuse by rebounding, so as to push the filler back into the arc initiation area of ​​the fuse.

2. The fuse according to claim 1, characterized in that, The filler includes an arc-quenching filler and a gas-generating filler. The arc-quenching filler is a solid particulate material, and the gas-generating filler can be decomposed by heat to generate gas, and the gas-generating filler occupies less than 10% of the volume of the filler.

3. The fuse according to claim 2, characterized in that, The particle size of the arc-quenching filler in the filler is set to 20-1000 mesh, and the material of the tube body is red steel paper fiber, melamine, ceramic, organic matter or glass.

4. The fuse according to claim 2 or 3, characterized in that, The arc-quenching filler includes quartz sand, and the gas-generating filler includes at least one of melamine, magnesium hydroxide, aluminum hydroxide, and ammonium salts.

5. The fuse according to claim 1 or 3, characterized in that, The filling amount of the filler and the compression ratio of the pre-tightening layer satisfy the following: H / (V-V1)<P<H / (V-V0), Wherein, H is the weight of the filler, V is the volume of the fuse cavity, V0 is the volume of the pre-tightening layer in its uncompressed state, V1 is the volume of the pre-tightening layer in its maximum compressed state, and P is the filling density of the filler. The compression ratio of the pre-tightening layer is set to be no less than 5%.

6. The fuse according to claim 1, characterized in that, The thickness of the pre-tightening layer accounts for 3-30% of the thickness of the fuse cavity.

7. The fuse according to claim 1, 3, or 6, characterized in that, The fusion section is a fusion wire, and the tube body is configured as a round or square tube of equal diameter.

8. The fuse according to claim 6, characterized in that, The pre-tightening layer can withstand reflow soldering at 260°C.

9. The fuse according to claim 1, characterized in that, The pre-tightening layer is made of polyurethane, silicone, rubber, or plastic.

10. A method for manufacturing a fuse as described in any one of claims 1-9, characterized in that, include: When the pre-tightening layer covers the inner surface of the fuse cavity corresponding to the end cap, the method includes: Insert the fused section into the tube body; A pre-tightening layer is inserted into one end of the tube, and the end cap of the corresponding end is pressed onto the pre-tightening layer to seal the end. The other end of the tube is the filling port. The filler is filled through the filling port, which compresses the pre-tightening layer at one end. Another pre-tightening layer is inserted into the filling port of the tube, and the end cap of the corresponding end is pressed onto the pre-tightening layer to seal the filling port, forming a fusion cavity. The two pre-tightening layers are squeezed to a preset compression amount and can expand toward the fusion part or be further compressed away from the fusion part. When the pre-tightening layer covers the inner surface of the tube corresponding to the fuse cavity, the method includes: The pre-tightening layer is inserted into the corresponding position inside the tube, or a pre-tightening layer is formed by bonding the pre-tightening layer to the corresponding position inside the tube using a pre-tightening layer forming solution. Insert the fused section into the tube body; The end cap is installed at one end of the tube body, and the other end is a filling port. After the filler is filled through the filling port, the end cap at the other end is installed, forming a fusible cavity. This allows the pre-tightening layer to be squeezed to a preset compression amount, and it can expand toward the fusible part or be further compressed away from the fusible part.

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