A hollow chip fuse and a manufacturing method thereof

Abstract

The application discloses a kind of hollow patch fuse and its manufacturing method, the patch fuse includes upper cavity plate, fuse and lower cavity plate, upper cavity plate and lower cavity plate are provided with etching electrode on the upper and lower surfaces of both ends, and the opposite surfaces of upper cavity plate and lower cavity plate are provided with adhesive layer;Upper cavity plate is provided with upper cavity, and upper cavity plate is provided with upper semicircular notch at both ends, and lower cavity plate is provided with lower semicircular notch at both ends, the radius of upper semicircular notch is greater than that of lower semicircular notch, to form a concave platform;The thickness of the sidewall of upper cavity plate is less than that of lower cavity plate, and upper cavity plate and lower cavity plate are centrally heat-pressed and adhered, and form an L-shaped glue holding platform;Fuse is placed between upper cavity plate and lower cavity plate;The both ends of fuse are plated with a layer of conductive material.The manufacturing method is easy to operate.The application greatly increases the contact area of plating layer and fuse, and the connection is reliable.The application improves the situation that adhesive layer is squeezed onto fuse, and also increases the bonding force of upper and lower cavity plates.

Description

TECHNICAL FIELD

[0001] The present application relates to a fuse and its manufacturing method, in particular to a hollow patch fuse and its manufacturing method. BACKGROUND

[0002] With the development of science and technology, electronic products are more and more, not only the function is stronger, the size is also smaller and smaller, the cost is also declining; for the passive components such as fuses applied to electronic products, it also requires smaller size, stronger performance and lower cost.

[0003] The size and performance are inversely proportional under normal circumstances. The traditional ceramic patch fuse has a ceramic tube, a fuse wire in the middle, and an end cap on both ends. Its capacity is mainly improved by continuously increasing the size, but the product volume is getting larger and larger, and the cost is also getting higher and higher, which cannot meet the market requirements.

[0004] As shown in Figure 1 Japanese patent "a method for making hollow fuse using 2 layer copper clad substrate (publication number JP6-244948)", the invention patent adopts the method of digging a cavity in the middle of the upper and lower PCBs, drilling holes at both ends, then arranging a fuse wire in the middle, coating glue on the cavity, and then hot pressing the upper and lower parts together to form a hollow structure. Through the drilled through hole, copper or other conductive materials are electroplated to connect the internal fuse wire with the external electrode. This invention patent has two problems:

[0005] 1. Reliability of connection. The connection is realized by the plating layer on the fuse wire and the external electrode. The plating layer is in the hole of the copper clad substrate, and the expansion coefficient of the copper clad substrate is several orders of magnitude different from that of the plating layer. When the product is assembled, the reflow soldering temperature reaches 260℃. According to the expansion coefficient of 10-20PPM / ℃ of the copper clad substrate, the expansion from 25℃ to 260℃ reaches 2350-4700PPM. Even for the smallest 6 size in the hollow product, the product length is 3.2mm, and the expansion is 7.52-15.4um. For larger products such as 2410, 4012 size, the expansion reaches 2-4 times. At the same time, after the fuse is installed on the product, it also needs to withstand the influence of high and low temperature in the environment during use. Therefore, such a large expansion difference leads to the risk of connection, especially for products with smaller fuse diameter or larger size.

[0006] In addition, the connection between the fuse wire and the plating layer is only the connection of the wire head close to the through hole, and the connection force is very small. When the product is cut and divided, the fuse wire is pulled by the blade, which is easy to cause cracks between the fuse wire and the plating layer, and safety hazards.

[0007] 2. The problem of press-fit glue overflow cannot be solved, resulting in low breaking capacity, and thicker fuses cannot be used, limiting product specifications (such as wire harnesses); the structure is symmetrical, glue is applied to the edges of the cavity, and then the two glued surfaces are pressed together, and the glue layer is squeezed into the cavity. The glue layer is generally organic (such as epoxy glue and acrylic glue), which is squeezed near or even on the fuse. When the fuse is overloaded and blown, the high temperature produced by the fuse will decompose and carbonize the glue layer. When the voltage is high, it will arc, causing the product to explode or burn, and other risks.

[0008] Only when the design is expanded, the thickness of the cavity wall is reduced, but the thinner the wall, the weaker the shell, and the breaking capacity cannot be improved.

[0009] For products with thicker fuses, the thickness of the glue layer needs to be increased, but the thickness of the glue layer increases, and the glue squeezed into the cavity also increases, so under the condition of a certain product size, the diameter of the fuse is limited.

[0010] Therefore, it is urgent for those skilled in the art to develop a hollow chip fuse and a manufacturing method thereof. SUMMARY

[0011] The present application provides a hollow chip fuse and a manufacturing method thereof to solve the above problems.

[0012] The above-mentioned purpose of the present application is achieved by the following technical scheme: a hollow chip fuse, comprising an upper cavity plate, a fuse and a lower cavity plate, the upper and lower surfaces of the upper and lower cavity plates are provided with etched electrodes, and the opposite surfaces of the upper and lower cavity plates are provided with glue layers;

[0013] The upper cavity plate is provided with an upper cavity, and the upper ends of the upper cavity plate are provided with upper semicircular notches. The lower cavity plate is provided with a lower cavity, and the lower ends of the lower cavity plate are provided with lower semicircular notches. The radius of the upper semicircular notch is greater than that of the lower semicircular notch, forming a concave platform.

[0014] The thickness of the side wall of the upper cavity plate is less than that of the side wall of the lower cavity plate, and the upper and lower cavity plates are centrally heat-pressed and fitted, so that the inner and outer sides of the bottom end of the side wall of the upper cavity plate and the upper end surface of the side wall of the lower cavity plate form an L-shaped glue holding platform.

[0015] The fuse is placed between the upper and lower cavity plates and located on the central axis after the upper and lower cavity plates are pressed together.

[0016] The ends of the fuse are plated with a layer of conductive material, which connects the etched electrodes and the fuse.

[0017] Further, the upper and lower cavity plates are copper-clad boards.

[0018] Further, the glue layer is a semi-cured adhesive.

[0019] Further, the conductive material layer is a metal conductive material such as copper or tin.

[0020] A manufacturing method of a hollow patch fuse, comprising the following steps:

[0021] S1: etching electrodes: etching electrodes on the outer surfaces of the upper and lower cavity plates;

[0022] S2: covering glue: covering a layer of semi-cured glue on the adhering surfaces of the upper and lower cavity plates, the semi-cured glue being semi-cured printing glue or semi-cured glue sheet;

[0023] S3: processing: processing a plurality of rows of upper cavities and upper through holes which are sequentially and alternately arranged on the upper cavity plate by drilling and milling, and processing a plurality of rows of lower cavities and lower through holes which are sequentially and alternately arranged on the lower cavity plate, wherein the upper cavities and the lower cavities are opposite in position but different in size, forming a stepped structure; the lower through holes and the lower through holes are opposite in position but different in size, forming a structure of coaxial through holes;

[0024] S4: arranging fuses and hot-pressing the upper and lower cavity plates: arranging fuses between the cavities and the through holes of the upper and lower cavity plates, and bonding the upper and lower cavity plates by hot pressing to form a "convex" cavity and an inverted "convex" through hole;

[0025] S5: plating a conductive material layer: plating a conductive material layer in the through hole and on the upper and lower ends of the through hole, so that the middle fuse is conductive with the etched electrodes;

[0026] S6: cutting: cutting each product into a single fuse by cutting machine from the middle of each through hole;

[0027] S7: detecting and packaging: testing the electrical performance of the product and packaging.

[0028] The advantages of the present application are that the fuses are placed between the upper and lower cavities, the upper and lower cavity plates are hot-pressed together by the glue layer preformed on the opposite surfaces of the upper and lower cavity plates, and the upper and lower cavities form a "convex" structure after adopting the asymmetrical structure, so that the glue remaining after pressing is significantly improved, and the L-shaped glue holding platform (stepped structure) at the joint of the upper and lower cavity plates allows the glue to remain on the L-shaped glue holding platform and not to flow into the cavity.

[0029] The bonding area of the upper and lower cavities is significantly increased under the condition that the fuses are at the same distance from the extruded glue layer, the upper cavity plate of the upper cavity is inserted into the glue layer to form a "U" shaped connection, so that the product bonding strength is increased and the product performance is improved.

[0030] Simultaneously, after lamination, the through holes on the upper and lower cavity plates form a stacked hole structure. In this way, a section of the fuse is placed on the concave platform between the upper and lower through holes. Then, conductive materials such as copper and tin are coated on the product, making the fuse and the plating conductive. The plating will cover the section of the fuse on the concave platform. Since this section of the plating is perpendicular to the through hole, there will be no situation where the plating on the hole wall and the copper-clad substrate have different coefficients of thermal expansion, which could cause the plating to peel off under certain conditions due to thermal expansion and contraction, resulting in the fuse being pulled up or even broken. During the cutting process, the fuse of traditional similar products with symmetrical structures is suspended outside the hole. The fuse is pulled by external forces such as cutting blades, which may cause damage to the wire end plating. However, this invention adopts an asymmetrical structure, and the fuse is supported by the concave platform, making it less susceptible to damage.

[0031] After adopting the stacked hole structure, the reliability of the connection is significantly improved. The connection area between the fuse and the coating is increased from the original cross-sectional circumference of the fuse to a section of the fuse, with the area increasing by several orders of magnitude. Under extreme bending, the reliability of the connection can still be maintained.

[0032] The advantages of this invention over the prior art are:

[0033] 1. By changing the plating from being perpendicular to the fuse to being parallel to the fuse, the contact area between the plating and the fuse is greatly increased. When the plating is peeled off from the copper-clad substrate by heat, there will be no force pulling the fuse or pulling force generated by the blade during cutting and granulation, thus ensuring the reliability of the connection.

[0034] 2. An asymmetrical cavity structure is adopted, allowing the extruded adhesive to flow into the L-shaped adhesive support platform between the upper and lower cavity plates during pressing. This not only improves the situation where the adhesive layer is squeezed onto the molten wire, but also increases the bonding force between the upper and lower cavity plates. Attached Figure Description

[0035] Figure 1 This is a structural diagram of existing technology.

[0036] Figure 2 This is a schematic diagram of the structure of the two fuses in this invention before they are cut.

[0037] Figure 3 This is a radial cross-sectional view (section) of the fuse in this invention.

[0038] Figure 4 This is a three-dimensional structural diagram of one end of the fuse of the present invention.

[0039] Figure 5 This is a schematic diagram showing the arrangement of the cavities and through holes on the upper and lower cavity plates in this invention.

[0040] Figure 6 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0041] The application will be further described in detail below with reference to the accompanying drawings.

[0042] As Figures 2 to 5 shown, a hollow patch fuse includes an upper cavity plate 1, a fuse 2 and a lower cavity plate 3, the upper cavity plate 1 and the lower cavity plate 3 are provided with etched electrodes 4 on the upper and lower surfaces of the two ends, and the upper cavity plate 1 and the lower cavity plate 3 are provided with adhesive layers 5 on the opposite surfaces;

[0043] The upper cavity plate 1 is provided with an upper cavity 6, and the upper cavity plate 1 is provided with upper semicircular notches 7 at the two ends, the lower cavity plate 3 is provided with a lower cavity 13, and the lower cavity plate 3 is provided with lower semicircular notches 8 at the two ends, the radius of the upper semicircular notch 7 is greater than that of the lower semicircular notch 8, forming a concave platform 9;

[0044] The thickness of the side wall of the upper cavity plate 1 is less than that of the side wall of the lower cavity plate 3, and the upper cavity plate 1 and the lower cavity plate 3 are centrally hot-pressed to form an L-shaped glue holding platform 10 between the inner and outer sides of the bottom end of the side wall of the upper cavity plate 1 and the upper end surface of the side wall of the lower cavity plate 3;

[0045] The fuse 2 is placed between the upper cavity plate 1 and the lower cavity plate 3 and located on the central axis after the upper cavity plate 1 and the lower cavity plate 3 are pressed;

[0046] The two ends of the fuse are plated with a conductive material layer 11 to conduct the etched electrodes 4 and the fuse 2.

[0047] Further, the upper cavity plate 1 and the lower cavity plate 3 are copper-clad boards.

[0048] Further, the adhesive layer 5 is a semi-cured adhesive.

[0049] Further, the conductive material layer 11 is a metal conductive material such as copper or tin.

[0050] As Figure 6 shown, a manufacturing method of a hollow patch fuse includes the following steps:

[0051] S1: etching electrodes 4: etching electrodes on the outer surfaces of the upper cavity plate 1 and the lower cavity plate 3;

[0052] S2: gluing: applying a layer of semi-cured adhesive on the surfaces of the upper cavity plate 1 and the lower cavity plate 3 to be attached, the semi-cured adhesive being semi-cured printing adhesive or semi-cured adhesive sheet;

[0053] S3: processing: as Figure 5As shown, by drilling or punching, several rows of upper cavities 6 and upper through holes 14 are processed on the upper cavity plate 1 in turn, and several rows of lower cavities 13 and lower through holes 15 are processed on the lower cavity plate 3 in turn, wherein the upper cavities 6 and the lower cavities 13 are opposite in position but different in size, forming a stepped structure; the lower through holes 15 and the lower through holes 15 are opposite in position but different in size, forming a structure of coaxial hole stacking.

[0054] S4: arranging the fuse 2 and hot pressing the upper and lower cavity plates 3: the fuse 2 is arranged between the cavities and the through holes of the upper cavity plate 1 and the lower cavity plate 3, and the upper cavity plate 1 and the lower cavity plate 3 are bonded by hot pressing, forming a "convex" cavity and a reversed "convex" through hole;

[0055] S5: plating a conductive material: a conductive material layer 11 is plated in the through hole and at the upper and lower ends of the through hole, so that the middle fuse 2 is in conduction with the etching electrode 4;

[0056] S6: cutting: using a cutting machine, the product is cut into a single fuse by cutting from the middle of each through hole;

[0057] S7: detection and packaging: testing the electrical performance of the product and packaging.

[0058] The advantages of the present application are that the fuse 2 is placed between the upper cavity 6 and the lower cavity 13, the upper and lower cavity plates 3 are hot pressed together by the adhesive layer 5 preformed on the opposite surfaces of the upper cavity plate 1 and the lower cavity plate 3, and after the upper and lower cavities adopt the asymmetric structure, the "convex" structure is formed, the condition of the glue left after pressing is obviously improved, and the L-shaped glue holding platform 10 (stepped) at the joint of the upper and lower cavity plates 3 is used to make the pressing glue 12 stay on the L-shaped glue holding platform 10 and not flow into the cavity. The specific comparison is as follows Figures 4-5 As shown.

[0059] The bonding area of the upper and lower cavities 13 is obviously increased under the condition that the fuse 2 is at the same distance from the extruded adhesive layer 5, the upper cavity plate 1 of the upper cavity 6 is inserted into the adhesive layer 5, forming a "U" shaped connection, so that in addition to the normal upper and lower bonding to generate the bonding force F1, the adhesive layer 5 on both sides provides an additional bonding force F2, thereby increasing the bonding strength of the product and improving the performance of the product.

[0060] Meanwhile, the upper through hole 14 of the upper cavity plate 1 and the upper through hole 14 of the lower cavity plate 3 form a stack hole structure after being pressed, so that the fuse 2 is placed on the inner recess platform 9 between the upper through hole 14 and the lower through hole 15; then the product is coated with a conductive material such as copper and tin, so that the fuse 2 is in conductive connection with the plating layer, and the plating layer covers the section of the fuse 2 on the inner recess platform 9, and the plating layer is perpendicular to the through hole, so that the plating layer on the hole wall of the through hole and the copper-clad substrate have different expansion coefficients, and under certain conditions, thermal expansion and cold contraction cause the plating layer to peel off, which causes the fuse 2 to be pulled up or even broken; in the cutting process, the symmetric structure of the fuse 2 of the traditional similar product is suspended outside the hole, and the fuse 2 is pulled by external force such as a cutting blade to cause damage to the plating layer of the wire head, and the present application adopts an asymmetric structure, and the fuse 2 is supported by the inner recess platform 9, so that the fuse 2 is not easy to be damaged.

[0061] After adopting the stack hole structure, the reliability of the connection is obviously improved, the connection area of the fuse 2 and the plating layer is increased from the original cross-sectional circumference of the fuse 2 to a section of the fuse 2, and the area is increased by several orders of magnitude; under extreme bending, the reliability of the connection can be maintained, as shown in Figure 2 and Figure 5 .

[0062] The above is only an embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and the drawings, or direct or indirect application in other related technical fields, is also included in the patent protection range of the present application.

Claims

1. A hollow patch fuse, characterized in that: It includes an upper cavity plate, a fuse, and a lower cavity plate. Etching electrodes are provided on the upper and lower surfaces of both ends of the upper and lower cavity plates, and an adhesive layer is provided on the opposite surfaces of the upper and lower cavity plates. The upper cavity plate is provided with an upper cavity, and the upper cavity plate has upper semi-circular notches at both ends. The lower cavity plate is provided with a lower cavity, and the lower cavity plate has lower semi-circular notches at both ends. The radius of the upper semi-circular notch is larger than that of the lower semi-circular notch, forming a concave platform. The thickness of the upper cavity plate sidewall is less than that of the lower cavity plate sidewall, and the upper cavity plate and the lower cavity plate are centered and hot-pressed together, so that an L-shaped adhesive support platform is formed between the inner and outer sides of the bottom end of the upper cavity plate sidewall and the upper end face of the lower cavity plate sidewall. The fuse is placed between the upper cavity plate and the lower cavity plate, and is located on the central axis after the upper cavity plate and the lower cavity plate are pressed together; The fuse has conductive material layers plated at both ends, which conduct the etched electrodes and fuse wire.

2. A hollow patch fuse according to claim 1, characterized in that: The upper cavity plate and the lower cavity plate are copper-clad substrates.

3. A hollow patch fuse according to claim 1, characterized in that: The adhesive layer is a semi-cured adhesive.

4. A hollow patch fuse according to claim 1, characterized in that: The conductive material layer is a metallic conductive material.

5. A method for manufacturing a hollow patch fuse as described in claim 1, characterized in that: Includes the following steps: S1: Etching electrodes: Etching electrodes at both ends of the unit product onto the outer surfaces of the upper and lower cavity plates; S2: Adhesive coating: A layer of semi-cured adhesive is applied to the mating surfaces of the upper cavity plate and the lower cavity plate. The semi-cured adhesive is a semi-cured printing adhesive or a semi-cured film. S3: Machining: Several rows of alternating upper cavities and upper through holes are machined on the upper cavity plate by drilling, milling or punching, and several rows of alternating lower cavities and lower through holes are machined on the lower cavity plate. The upper and lower cavities are opposite each other but have different sizes, forming a stepped shape; the lower through holes are opposite each other but have different sizes, forming a structure of coaxial upper holes stacked with lower holes. S4: Arrange fuse wires and hot-press to bond the upper and lower cavity plates: Arrange fuse wires between the cavity and through hole of the upper and lower cavity plates, and bond the upper and lower cavity plates together by hot pressing to form a "convex" shaped cavity and an inverted "convex" shaped through hole. S5: Apply conductive material: Apply a conductive material layer in the through hole and at the upper and lower ends of the through hole to make the fuse in the middle conductive with the etched electrode. S6: Cutting: Using a cutting machine, cut the product into individual fuses from the middle of each through hole; S7: Testing and Packaging: Test the electrical properties of the product and package it.

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