Fuse and manufacturing method thereof

Abstract

The invention 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 fuse filler, the invention provides a fuse and a manufacturing method thereof, the fuse comprises a tube body, the tube body is provided with two opposite ports, the two ports of the tube body are provided with end caps, and a fusing cavity is formed in the tube body; the filler is filled in the fusing cavity and is used for arc extinguishing; at least one port of the pipe body is set as a filling port and is used for filling the filler; the fusing part is arranged in the fusing cavity in a penetrating manner; and the pre-tightening layer at least covers part of the inner surface of the fusing cavity, and the pre-tightening layer extrudes the filler, can expand towards the fusing part and can also be further compressed away from the fusing part. The pre-tightening layer extrudes the filler, so that the filling density of the filler is improved, and the breaking capacity of the fuse is improved.

Description

Technical Field

[0001] The present application relates to the technical field of fuses, and in particular to fuses and methods for manufacturing the same. Background Art

[0002] With the development of science and technology and the improvement of environmental protection awareness, the new energy revolution is an inevitable trend, especially in the new energy industry represented by electric vehicles / energy storage, which has higher and higher requirements for fuses. First of all, the voltage. The traditional fuse of 250V can meet general applications, but the voltage of new energy is getting higher and higher for higher efficiency. For example, electric vehicles have increased from 380V to 800V, but the volume of the fuse cannot be increased, which adds new requirements for the arc extinguishing of the fuse; secondly: sealing. The application environment of the vehicle is relatively complex. If the sealing is not good, water vapor / salt spray / corrosive gas will enter the interior, affecting the life of the fuse, and seriously affecting the electrical performance.

[0003] Traditional fuses are usually composed of a glass tube / ceramic tube with a fuse in the middle. Some products are also filled with fillers (fillers) in the middle and end caps at both ends. The end sleeves are in direct hard contact with the porcelain tube / glass tube, and the seal is not good. Water mist can directly penetrate into the internal fuse. At the same time, the filler cannot be pressed densely. After filling the filler, the end cap is directly pressed on. The bottom of the cap is flat and is also flat with the plane of the filler, so it cannot be dense and the breaking capacity is limited.

[0004] There are corresponding improvements in the prior art to the above-mentioned problems. For example, a Chinese patent application with a publication date of 2022-11-01 and publication number CN115274375A clearly points out that the traditional fuse, which is filled with quartz sand, cannot guarantee the filling density. Therefore, the filler is made into a mixed slurry and filled, and then the solvent is removed by multiple baking to achieve a certain filling density. The shortcomings of this solution are: 1. The mixture filler contains a large amount of solvent (alcohol, resin, etc.), which is removed by baking, forming continuous channels extending from the inside and outside. These channels are also channels for the subsequent arc propagation, which is disadvantageous for arc extinguishing, especially for high-voltage products. There are potential safety hazards; 2. Bubbles cannot be eliminated during the mixture filling process, which can easily cause local voids and affect arc extinguishing. Specifically, the filler needs to be sealed at one end and filled from the other end. Generally, fuses have a long aspect ratio, such as a 6*32mm tube. If honey is poured into a glass bottle, there will be a lot of bubbles, and the solid matter in the filler reaches more than 70%, and its density is much higher than honey, and it cannot be guaranteed that there are no bubbles in the mixture; 3. Low efficiency and high cost, that is, first mix the materials, then fill them, and then let them stand for 72 hours, and finally multiple rounds of baking.

[0005] For another example, the Chinese patent application with the publication date of December 21, 2021 and the publication number of CN215266173U adopts a scheme of opening a small hole in the fuse housing and then sealing it with a plug to ensure the filling density and reliability. The disadvantages of this scheme are as follows: 1. The filling density cannot be guaranteed. It is inconvenient to fill the filler into a cavity with a small opening and a large belly. There is no clear standard for whether it is filled, and it is not easy to observe visually. If the filling density cannot reach a certain level, the arc extinguishing ability will decrease significantly. At the same time, if a mixed slurry is used for filling, the problem of air bubbles cannot be solved; 2. After the housing is opened, its overall strength decreases significantly, especially at the opening position, which is not conducive to withstanding pressure during breaking and instead affects the breaking ability. Specifically, when the fuse melts, the fuse gasifies, and the arc can reach several thousand or even hundreds of thousands of degrees Celsius. The air pressure in the housing expands dozens or even thousands of times, which may cause the plug at the opening position to be ejected or even the housing to break; 3. The sealing performance at the plug hole cannot be guaranteed. There is no pressing device above the plug, and it may loosen under high-frequency vibration. Summary of the Invention

[0006] The purpose of this application is to solve the problem of low filling density of the filler in the prior art. Therefore, this application provides a fuse and its manufacturing method. The fuse improves the filling density of the filler by squeezing the filler through a pre-tightening layer, thereby improving the breaking ability of the fuse.

[0007] An embodiment of this application provides a fuse, which includes a tube body. The tube body has two opposite ports. End caps are provided at the two ports of the tube body, and a fusing cavity is formed in the tube body;

[0008] A filler, filled in the fusing cavity and used for arc extinguishing;

[0009] At least one of the ports of the tube body is set as a filling port and is used for filling the filler;

[0010] A fusing part, passing through the fusing cavity;

[0011] A pre-tightening layer, covering at least a part of the inner surface of the fusing cavity. The pre-tightening layer squeezes the filler and can expand towards the fusing part or be further compressed away from the fusing part.

[0012] By adopting the above technical solution, the filling density of the filler is improved by squeezing the filler through the pre-tightening layer, thereby improving the breaking ability of the fuse; moreover, the pre-tightening layer can still be further compressed, so as to provide space for the volume expansion in the fusing cavity during fusing, reduce the possibility of damage to the pre-tightening layer, and then achieve rebound after the expanded volume shrinks. At the same time, the rebound of the pre-tightening layer can push the filler that moves outward during fusing to move in the reverse direction, that is, bounce back to the fusing position of the fusing part, thereby improving the arc extinguishing ability and further improving the breaking ability.

[0013] In some embodiments, the filler includes an arc extinguishing filler and a gas generating filler. The arc extinguishing filler is set as solid particles, the gas generating filler can be decomposed by heat to generate gas, and the volume of the gas generating filler in the filler is less than 10%.

[0014] Adopting the above technical solution, by mixing a gas generating filler into the usually provided arc extinguishing filler, the amount of gas generated during the breaking process is increased, thereby further enhancing the arc extinguishing ability of the pre-tightening layer to rebound and improving the breaking ability. Moreover, by limiting the ratio of the arc extinguishing filler to the gas generating filler, it is avoided that the fuse explodes due to excessive gas volume, and it is also avoided that the insufficient amount of the arc extinguishing filler in the limited volume of the fuse cavity affects the arc extinguishing effect, and the pre-tightening layer appropriately rebounds to the arc extinguishing filler to make the rebounding arc extinguishing filler fill the fuse-breaking place, ensuring the arc extinguishing effect. At the same time, the solid particles have better fluidity, so as to improve the efficiency and tightness of the arc extinguishing filler rebounding to the fuse-breaking place, thereby further improving the breaking ability.

[0015] In some embodiments, the particle size of the arc extinguishing 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 extinguishing 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 pre-tightening layer satisfy:

[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 the uncompressed state, V1 is the volume of the pre-tightening layer in the 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 not 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 fuse part is a fuse wire, and the tube body is set as an equal-diameter round tube or a square tube.

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

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

[0025] The embodiment of the present application also provides a manufacturing method of the fuse described in any one of the above, 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 fusing part into the tube body;

[0028] Insert a pre-tightening layer at one end of the tube body, press the end cap corresponding to the end onto the pre-tightening layer to seal the end, and the other end of the tube body is the filling port;

[0029] Fill the filler through the filling port so that the pre-tightening layer at one end is squeezed;

[0030] Insert another pre-tightening layer into the filling port of the tube body, press the end cap corresponding to the end onto the pre-tightening layer to seal the filling port, and form a fuse cavity, and make the two pre-tightening layers be squeezed to a preset compression amount, and can expand towards the fusing part or be further compressed away from the fusing part;

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

[0032] Insert the pre-tightening layer into the corresponding position in the tube body, or form the pre-tightening layer by compounding the pre-tightening layer forming solution at the corresponding position in the tube body;

[0033] Insert the fusing part into the tube body;

[0034] Install the end cap at one end of the tube body, the other end is the filling port, install the end cap at the other end after filling the filler through the filling port, and form a fuse cavity, and make the pre-tightening layer be squeezed to a preset compression amount, and can expand towards the fusing part or be further compressed away from the fusing part.

[0035] Adopting the above technical solution, the manufacturing is convenient, and by squeezing the filler through the pre-tightening layer, the filling density of the filler is improved, thereby improving the breaking capacity of the fuse.

[0036] Other features and corresponding beneficial effects of the present application are described and explained in the following part of the specification, and it should be understood that at least some of the beneficial effects are obvious from the description in the specification of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1(a) is a schematic structural diagram of a fuse with a double-end pre-tightening layer according to the present application;

[0038] FIG. 1(b) is a schematic diagram of the state of the fuse in FIG. 1(a) during rapid fusing;

[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 structural diagram of another fuse with a double-ended pre-tightening layer according to the present application;

[0041] Figure 2(b) is a schematic structural diagram of a fuse with a single-ended pre-tightening layer according to the present application;

[0042] Figure 3(a) is a schematic structural diagram of a fuse with a double-layer pre-tightening layer according to the present application;

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

[0044] Explanation of reference numerals:

[0045] End caps 101, 102;

[0046] Pre-tightening layers 201, 202;

[0047] Fusing part 300; Tube body 400; Filler 500. Specific embodiments

[0048] The following specific embodiments illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Although the description of the present application will be introduced in conjunction with preferred embodiments, this does not mean that the features of this application are limited to this implementation manner. On the contrary, the purpose of introducing the application in conjunction with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusing or obscuring the key points of the present application, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

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

[0050] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. In addition, terms such as "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. Unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0051] It should be noted that currently, fuses usually use quartz sand or similar fillers to improve the breaking capacity. If the filler is too sparse, resulting in large pores, it is easy to form an arc. The arc voltage formed will damage the subsequent protection circuit, and the sparse filler is also not conducive to the normal heat dissipation of the fusing part, which will also affect the breaking capacity. Therefore, current fuses pursue dense filling, and even a mixed slurry filler has emerged. It can completely fill the fusing cavity in a liquid form (subsequently dried into a solid) to block the arc and achieve rapid arc extinction. However, on the one hand, the mixed slurry filler has a high cost and still has many problems as described in the background art; on the other hand, the mixed slurry filler is usually applied to fuses with high specifications and large-diameter fuses. Since the mixed slurry filler directly extinguishes the arc through the filler for the fusing part, in order to ensure the breaking capacity, usually such fuses need to split the large-diameter fusing part (usually a fuse) into multiple small-diameter fusing parts connected in parallel, resulting in a further increase in processing costs. At the same time, it is difficult to ensure the consistency of multiple small-diameter fusing parts, and it is easy to have uneven current distribution. Some fusing parts cannot be disconnected in time, resulting in circuit overload, or some fusing parts exceed their breaking capacity, resulting in ineffective arc extinction and other problems.

[0052] However, with the increasing demand for breaking capacity, the dense filler cannot further increase the breaking capacity. Only with the increasing demand for breaking capacity, the thickness and volume of the granular filler need to be further increased to ensure the arc extinguishing ability.

[0053] Please refer to FIGS. 1(a), 2(a), 2(b), 3(a) and 3(b). FIG. 1(a) is a schematic structural diagram of a fuse with double-end pre-tightening layers 201 and 202 according to the present application; FIG. 2(a) is a schematic structural diagram of another fuse with double-end pre-tightening layers 201 and 202 according to the present application, and the difference between it and FIG. 1(a) lies in the different contact modes of the fusing part 300 passing through the pre-tightening layers 201 and 202 and contacting the end caps 101 and 102; FIG. 2(b) is a schematic structural diagram of a fuse with a single-end pre-tightening layer according to the present application; FIG. 3(a) is a schematic structural diagram of a fuse with double pre-tightening layers 201 and 202 according to the present application; FIG. 3(b) is a schematic structural diagram of a fuse with a single pre-tightening layer according to the present application.

[0054] An embodiment of the present application provides a fuse, which includes a tube body 400, a filler 500, a fusing part 300 and a pre-tightening layer.

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

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

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

[0058] The fusing part 300 is arranged in the fusing cavity. The fusing part 300 can be in the shape of a sheet, a filament or other shapes.

[0059] The pre-tightening layers 201 and 202 at least cover a part of the inner surface of the fusing cavity. For example, the pre-tightening layer can be double-layer or single-layer, can be left and right, can be up and down, can also be a full circumferential wrap of the tube body 400, or a wrap of the tube body 400 and the end caps, etc. Preferably, the pre-tightening layers 201 and 202 cover the inner surfaces of the fusing cavity corresponding to the two end caps 101 and 102, so as to improve the sealing performance between the ports of the tube body 400 and the end caps 101 and 102, thereby improving the sealing performance of the fuse, protecting the internal fusing part 300 from being affected by the external environment, being applicable to harsh environments, and being relatively simple to manufacture.

[0060] The fuse squeezes the filler 500 through the pre-tightening layers 201 and 202, which can improve the filling density of the filler 500, and further improve the breaking capacity of the fuse. Moreover, this densification method has a low cost. Only by adding the pre-tightening layers 201 and 202 outside the traditional filler 500 can the arc extinguishing effect be greatly improved and the breaking capacity be improved.

[0061] Please refer to FIGS. 1(b) and 1(c). FIG. 1(b) is a schematic diagram of the state of the fuse in FIG. 1(a) during rapid fusing; FIG. 1(c) is a schematic diagram of the state of the pre-tightening layers 201 and 202 in FIG. 1(a) when they rebound.

[0062] It should be noted that the overly dense filler 500 results in too low porosity of the overly dense filler 500, making the plasma generated during the fusing process unable to fully penetrate into the filler 500, resulting in the breaking capacity of the filler 500 not being fully exerted.

[0063] Therefore, in one embodiment, the pre-tightening layers 201 and 202 can expand towards the fusing part 300 or be further compressed away from the fusing part 300. Specifically, the pre-tightening layers 201 and 202 are further compressed away from the fusing part 300, so as to provide space for the volume expansion in the fusing cavity during fusing, making the pores between the fillers 500 larger, so that the plasma gas formed by the fusing of the fuse quickly and fully diffuses into the pores of the filler 500 and contacts it for heat dissipation. At this time, the rebound force of the pre-tightening layers 201 and 202 is enhanced and can expand rapidly towards the fusing part 300, that is, it rebounds after the expanded volume retracts, thereby pushing the filler 500 to be re-compacted, making the filler 500 squeeze the plasma gas in the pores, greatly enhancing the arc extinguishing ability of the filler 500, and further improving the breaking capacity.

[0064] It should be noted that when the fusing part 300 breaks, it will vaporize (i.e., at the position indicated by 330 and in the expanded state A1), and generate high temperature, increasing the pressure in the fusing space, thereby squeezing the pre-tightening layers 201 and 202 to be compressed. When the vaporized substance of the fusing part 300 contacts the filler 500 and cools (i.e., in the contracted state B1), the temperature drops, the pre-tightening layers 201 and 202 rebound, driving the filler 500 to rebound to the arc starting area together to extinguish the arc. This process is usually at the microsecond level.

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

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

[0067] Preferably, the arc extinguishing filler is set as solid particles, and the solid particles have better fluidity and better cooperation with the pre-tightening layers 201 and 202, which can improve the efficiency and tightness of the arc extinguishing filler rebounding to the fusing place, thereby further improving the breaking capacity. Further preferably, the arc extinguishing filler includes quartz sand, and the cost is controllable.

[0068] In one embodiment, the filler 500 further includes a gas-generating filler which can be decomposed by heat to generate gas. That is, the gas-generating filler is mixed into the usually provided arc-extinguishing filler, so that the amount of gas generated during the breaking process increases, and the force and speed of compression and rebound of the pre-tightening layers 201 and 202 increase, thereby further enhancing the arc-extinguishing ability of the rebound of the pre-tightening layers 201 and 202 and improving the breaking ability.

[0069] Preferably, the volume of the gas-generating filler in the filler 500 is less than 10%, preferably 0.5%-3%.

[0070] By limiting the ratio of the arc-extinguishing filler to the gas-generating filler in this way, it is possible to avoid the fuse bursting due to excessive gas production, and at the same time, it is possible to avoid insufficient arc-extinguishing filler in the fuse cavity of limited volume affecting the arc-extinguishing effect. In addition, it is also possible to achieve proper rebound of the pre-tightening layers 201 and 202 on the arc-extinguishing filler so that the rebound arc-extinguishing filler fills the fuse-breaking place, ensuring the arc-extinguishing effect.

[0071] In one embodiment, the particle size of the arc-extinguishing filler in the filler 500 is set to 20-1000 mesh. And the thicker the fusing part 300 is, the smaller the mesh number of the selected arc-extinguishing filler is.

[0072] In one embodiment, the fusing part 300 is a fuse wire, and its material can be a low-melting-point material fuse wire according to different current requirements, such as a lead-tin alloy. Because its melting point is relatively low, about 200°C, it can quickly fuse when the current is too large to protect the circuit. This kind of fuse wire has high sensitivity and is especially suitable for small-current circuits, such as household appliances, and has good arc-extinguishing performance, with little impact on the fuse. For high-current circuits, such as industrial electrical equipment, a high-melting-point material fuse wire, such as metals like silver and copper, needs to be selected. These metals have high melting points, 960°C for silver and as high as 1080°C for copper. They can withstand large currents, have excellent electrical conductivity, low resistivity, and produce less metal vapor during fusing, making it easy to extinguish the arc.

[0073] In one embodiment, the tube body 400 is set as an equal-diameter round tube or a square tube. Preferably, the diameter (width) of the tube body 400 is 2-13 mm and the length is 5-50 mm. At this time, the diameter of the fusing part 300 is preferably less than 0.5 mm; when the diameter (width) of the tube body 400 is greater than 13 mm and the length is greater than 50 mm, the diameter of the fusing part 300 is preferably greater than 1 mm.

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

[0075] In one embodiment, the gas-producing filler includes at least one of melamine, magnesium hydroxide, aluminum hydroxide, and ammonium salts to meet the requirement of high temperature resistance and avoid decomposition under the heating conditions during the normal operation of the fuse.

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

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

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

[0079] Preferably, the compression ratio of the pre-tightening layers 201 and 202 is set to be not less than 5%, 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 the normal state of the fuse, that is, before fusing. Preferably, the larger the compression ratio of the pre-tightening layer, 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 large, the further compression space will become smaller, the expansion space will be insufficient, and the pores of the arc extinguishing filler will increase extremely limitedly, resulting in a weak arc extinguishing effect; while if the compression ratio is too small, the further compression space will be too large, the expansion space will be too large, the pores of the arc extinguishing filler will be too large, and the rebound cannot be compacted, also resulting in a weak arc extinguishing effect.

[0081] Furthermore, the larger 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 a 260°C reflow soldering, and can still maintain elasticity even after passing through a 260-degree reflow soldering.

[0083] In one embodiment, the materials of the pre-tightening layers 201 and 202 are polyurethane, silica gel, rubber, plastic or elastic sheets.

[0084] In one embodiment, the thickness of the pre-tightening layers 201 and 202 accounts for 3 - 30% of the thickness of the fuse cavity. Preferably, when the pre-tightening layer 201 or 202 is arranged at the end, its thickness is thicker than that when arranged circumferentially.

[0085] The embodiment of the present application also provides a manufacturing method of a fuse for manufacturing the above-mentioned fuse, which is convenient to manufacture, and the filling density of the filler 500 is increased by extruding the filler 500 through the pre-tightening layers 201 and 202, thereby improving the breaking capacity of the fuse.

[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 fusing cavity, it is preferable to prepare a fuse having double-end pre-tightening layers 201 and 202 as shown in FIGS. 1(a) and 2(a). The preparation method includes:

[0087] Insert the fusing portion 300 into the tube body 400.

[0088] Insert the pre-tightening layer 201 at one end of the tube body 400, press the corresponding end cap 101 onto the pre-tightening layer 201 to seal this end, and the other end of the tube body 400 is the filling port.

[0089] Fill the filler 500 through the filling port so that the pre-tightening layer 201 at one end is squeezed.

[0090] Insert another pre-tightening layer 202 into the filling port of the tube body 400, press the corresponding end cap 102 onto this pre-tightening layer 202 to seal the filling port, and form a fusing cavity, and make the two pre-tightening layers 201 and 202 be squeezed to a preset compression amount, and can expand towards the fusing portion 300 or be further compressed away from the fusing portion 300.

[0091] It can be understood that the fusing portion 300 needs to avoid the pre-tightening layers 201 and 202 at both ends and be connected to the external lead-out wires through the end caps 101 and 102. For example, in FIG. 1(a), it can directly pass through the middle of the pre-tightening layers 201 and 202, or as in FIG. 2(a), it can pass through the edges of the pre-tightening layers 201 and 202.

[0092] This method can improve the sealing performance at the connection between the tube body 400 and the end caps 101 and 102 by correspondingly assembling the pre-tightening layers 201 and 202 with the end caps 101 and 102, thereby improving the sealing performance of the fuse.

[0093] In one embodiment, when the pre-tightening layers 201 and 202 cover the inner surface of the corresponding tube body 400 of the fusing cavity, it is preferable to prepare a fuse having double-layer pre-tightening layers 201 and 202 as shown in FIG. 3(a), or a fuse with a pre-tightening layer that completely covers the inner wall circumference of the tube body 400. The preparation method includes:

[0094] Insert the pre-tightening layers 201 and 202 into the corresponding positions inside the tube body 400, or form the pre-tightening layers 201 and 202 by compounding the pre-tightening layer forming solution at the corresponding positions inside the tube body 400.

[0095] Insert the fusing portion 300 into the tube body 400.

[0096] A end cap 101 is installed at one end of the installation pipe body 400, and the other end is a filling port. After filling the filler 500 through the filling port, the end cap 102 at the other end is installed to form a fusing cavity, and the pre-tightening layers 201 and 202 are squeezed to a preset compression amount, and can expand towards the fusing part 300 or be further compressed away from the fusing part 300.

[0097] This method has a simpler process. Only by processing the pipe body 400 to attach a layer of pre-tightening layers 201 and 202, the other processes are basically no different from traditional fuses, and existing mature equipment can be better utilized for mass production.

[0098] It can be understood that when the pre-tightening layer forming solution is used to form the pre-tightening layers 201 and 202 at corresponding positions inside the pipe body 400, the parts that do not need to be covered need to be protected to avoid being covered with the pre-tightening layers 201 and 202.

[0099] In other alternative embodiments, a fuse in which the end part and the circumferential direction of the pipe body 400 are both covered with the pre-tightening layers 201 and 202 can also be prepared by combining the above methods.

[0100] In one embodiment, the pipe body material is ceramic, with a size of 10 - 40 mm in diameter and 40 - 60 mm in length.

[0101] In one embodiment, the material of the pre-tightening layer is silica gel or mica, and the compression ratio is 50 - 70%.

[0102] Test the fuse of the present application:

[0103] Example 1:

[0104] A porcelain tube with a diameter of 10 mm and a length of 38 mm, internally filled with quartz sand of 60 - 200 mesh plus 5% magnesium hydroxide as a gas-producing substance, and both ends are provided with a silica gel pre-tightening layer with a thickness of 2.2 mm and a compression ratio of 50%. Its fuse wire is a 0.2 mm diameter alloy wire, with a specification of 10 A and a breaking capacity of 1000 VDC 1 KA. 5 pieces are tested and all can work normally.

[0105] Example 2:

[0106] The rest is the same as Example 1, and the difference is that:

[0107] The silica gel pre-tightening layer with a compression ratio of 50% is replaced with a highly elastic silica gel with a compression ratio greater than 70%. Its breaking capacity is 1000 VDC 1 KA. 5 pieces are tested and 1 piece explodes, with a certain abnormal rate.

[0108] Example 3:

[0109] The rest is the same as Example 1, and the difference is that:

[0110] Replace the silica gel pre-tightening layer with a compression ratio of 50% with mica flakes with a compression ratio of less than 10%. Its breaking capacity is 1000 VDC 1 KA. Five were tested, and three exploded, with a relatively high abnormal ratio.

[0111] Comparative Example 1:

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

[0113] Under the test requirement of 1000 VDC 1 KA, all five were shattered.

[0114] Example 4:

[0115] In a porcelain tube with a diameter of 38 mm and a length of 58 mm, it is filled with quartz sand with a particle size of 20 - 100 mesh plus 2% magnesium hydroxide as the gas-generating substance. The four sides of the porcelain tube wall are provided with a silica gel pre-tightening layer with a compression ratio of 50% and a thickness of 2.0 mm. Its fuse is an alloy sheet with a thickness of 0.2 mm, and there are multiple variable clamp traps on it, equivalent to multiple strands of fuses, with a specification of 300 A and a breaking capacity of 800 VDC 20 KA. Three were tested and all could work normally.

[0116] Comparative Example 2:

[0117] The product size is the same as in Example 1, but the filling is a mixture of 20 - 100 mesh quartz sand and water glass. After filling it into the porcelain tube, it is baked at 80 degrees for 24 hours to remove the moisture of the water glass. The breaking capacity is 800 VDC 20 KA. Three were tested and two exploded.

[0118] Table 1:

[0119]

[0120] It can be seen that the fuse of the present application has better performance.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A fuse, characterized in that, It includes a tube body which has two opposite ports. End caps are provided at the two ports of the tube body, and a fusing cavity is formed inside the tube body; A filler, which is filled in the fusing cavity and is used for arc extinguishing; At least one of the ports of the tube body is set as a filling port and is used for filling the filler; A fusing part, which is inserted through the fusing cavity; A pre-tightening layer, which covers at least part of the inner surface of the fusing cavity. The pre-tightening layer squeezes the filler and can expand towards the fusing part or be further compressed away from the fusing part.

2. The fuse according to claim 1, wherein, The filler includes an arc-extinguishing filler and a gas-generating filler. The arc-extinguishing filler is set as solid particles, and the gas-generating filler can be decomposed by heat to generate gas, and the volume of the gas-generating filler in the filler is less than 10%.

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

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

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: H / (V-V1)<P<H / (V-V0), wherein, H is the weight of the filler, V is the volume of the fusing cavity, V0 is the volume of the pre-tightening layer in the uncompressed state, V1 is the volume of the pre-tightening layer in the maximum compressed state, and P is the filling density of the filler; The compression ratio of the pre-tightening layer is set to be not less than 5%.

6. The fuse according to any one of claims 1-5, characterized in that, The thickness of the pre-tightening layer accounts for 3-30% of the thickness of the fusing cavity.

7. The fuse according to claim 1, 3 or 6, characterized in that, The fusing part is a fuse wire, and the tube body is set as an equal-diameter round tube or a square tube.

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

9. The fuse according to claim 1, characterized in that, The material of the pre-tightening layer is polyurethane, silica gel, rubber or plastic.

10. A manufacturing method of a fuse as described in any one of claims 1-9, characterized in that, It includes: When the pre-tightening layer covers the inner surface of the fusing cavity corresponding to the end cap, the method includes: Insert the fusing part into the tube body; Insert the pre-tightening layer at one end of the tube body, press the end cap at the corresponding end onto the pre-tightening layer to seal this end, and the other end of the tube body is the filling port; Fill the filler through the filling port so that the pre-tightening layer at one end is squeezed; Insert another pre-tightening layer at the filling port of the tube body, press the end cap at the corresponding end onto this pre-tightening layer to seal the filling port, and form a fusing cavity, and make the two pre-tightening layers be squeezed to a preset compression amount and can expand towards the fusing part or be further compressed away from the fusing part; When the pre-tightening layer covers the inner surface of the fusing cavity corresponding to the tube body, the method includes: Insert the pre-tightening layer into the corresponding position inside the tube body, or form the pre-tightening layer by compounding the pre-tightening layer forming solution at the corresponding position inside the tube body; Insert the fusing part into the tube body; Install the end cap at one end of the tube body, the other end is the filling port. After filling the filler through the filling port, install the end cap at the other end and form a fusing cavity, and make the pre-tightening layer be squeezed to a preset compression amount and can expand towards the fusing part or be further compressed away from the fusing part.

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