A surface-mounted fuse applied to a switching power supply

Abstract

The present invention relates to a surface-mount fuse for use in a switching power supply. The present invention includes a fuse replacement part and a fuse welding part; the fuse replacement part includes an upper base plate, a fuse body, and a latch; the fuse body is fixedly mounted in the inner cavity of the upper base plate; the slot body plug-in part of the fuse body is exposed at the lower part of the upper base plate; the latch of the latch is connected to the lower part of the upper base plate; the fuse welding part includes a lower base plate, a first end face electrode, a second end face electrode, a metal slot, and a latch slot of the latch; the first end face electrode and the second end face electrode are respectively fixed at the left and right ends of the lower base plate; the metal slot is provided at the upper part of the lower base plate for plugging into the slot body plug-in part; the latch slot is connected to the upper part of the lower base plate. The present invention has a fast and clean fusing capability, and can meet the requirements of developers for multiple fuses or the requirements for multi-stage fusing with different fusing currents in parallel.

Description

Technical Field

[0001] The present invention relates to the technical field of fuses, in particular to a chip fuse applied to a switching power supply. Background Art

[0002] With the development of power electronics technology, power modules have been widely used in various fields. Switching power supplies have gradually replaced linear power supplies and become the mainstream power supply. The power of equipment is mainly provided by switching power supplies. One of the performance indicators of switching power supplies is the use of fuses.

[0003] Fuses are common electrical components that provide protection in circuits. When a circuit is overloaded, fuses typically break current, causing the fuse element to heat and quickly melt, disconnecting the circuit and providing protection. Surface mount overcurrent fuses are compact and easy to install. When the current in a circuit exceeds the safe value for equipment use, the fuse element in a series-connected surface mount overcurrent fuse will heat up and melt, effectively disconnecting the circuit and preventing damage to the switching power supply.

[0004] As switching power supplies become more common and smaller, the convenience, safety, reliability, and circuit protection of fuses are gaining increasing attention from developers and users. In particular, switching power supply protection must meet stringent requirements: fuse characteristics should be clean and sharp, with high post-break resistance, the entire fusing process must occur within the package, arc suppression characteristics must be excellent, and the device must be able to withstand shock and vibration. Because smart devices require replacement of chip fuses with different breaking currents during debugging, and may also require the use of fuses in parallel or with multiple stages of fusing, fuse replacement should be quick to ensure efficient R&D.

[0005] However, due to the limitation on the number of soldering times of PCB pads, it is necessary to avoid frequent heating and soldering of the fuse pads as much as possible. The breaking capacity refers to the maximum current value at which the fuse can safely disconnect the circuit without damage under the rated voltage. When the fuse blows, it needs to be separated quickly and cleanly. It should not be affected by other factors. However, existing chip fuses can only have one type of fuse wire and one melting current. If you want to use them in parallel or want multi-stage melting, you need to connect multiple fuses in parallel or combine multiple fuses to form a multi-stage melting. This not only wastes space on the PCB, but also delays time. At the same time, the melting of existing fuses may not be quick and clean due to material and space limitations. In addition, once an existing fuse is damaged, you have to replace the entire fuse, which is not only troublesome but also affects the life of the PCB. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a chip fuse for use in a switching power supply, which has a fast and clean fusing capability and can meet the requirements of developers for multiple fuses or multi-stage fusing with different fusing currents in parallel.

[0007] The technical solution adopted by the present invention to achieve the above-mentioned object is: a chip fuse applied to a switching power supply, comprising a fuse replacement part and a fuse welding part;

[0008] The fuse replacement part includes an upper base plate, a fuse body, and a lock buckle; the fuse body is provided in a plurality and fixedly mounted in the inner cavity of the upper base plate; the slot body connecting portion of the fuse body is exposed at the lower portion of the upper base plate; the lock buckle is connected to the lower portion of the upper base plate;

[0009] The fuse welding portion includes a lower base plate, a first end surface electrode, a second end surface electrode, a metal slot, and a locking slot of a lock buckle; the first end surface electrode and the second end surface electrode are respectively fixed to the left and right ends of the lower base plate and are fully or partially exposed from the lower base plate; the metal slots are arranged on the upper part of the lower base plate, and the number and size correspond to the fuse body, and are used to plug into the slot body plug-in part of the fuse body; the locking slot of the lock buckle is connected to the upper part of the lower base plate and corresponds to the locking buckle of the lock buckle;

[0010] The upper substrate is connected to the lower substrate through the lock.

[0011] The upper base plate includes an integrally formed upper cover plate, a left cover plate, a right cover plate, a front cover plate and a rear cover plate, and also includes a bottom cover plate, which connects the left cover plate, the right cover plate, the front cover plate and the rear cover plate; the middle part of the bottom cover plate has a triangular cone-shaped protrusion from the front cover plate to the rear cover plate, and is also provided with a circular opening corresponding to the fuse body.

[0012] The lower base plate includes an integrally formed left cover plate, a right cover plate, a front cover plate, a rear cover plate and a bottom cover plate, and also includes an upper cover plate, the upper cover plate is provided with a triangular pyramidal groove corresponding to the raised portion of the bottom cover plate, and is also provided with an opening corresponding to the circular opening, and the metal slot is arranged in the opening.

[0013] It also includes an even number of elastic elements, one end of each of which is connected to the inner wall of the left cover plate / the right cover plate, and the other end of each of which is connected to the triangular pyramidal groove.

[0014] The lock buckle includes a buckle and a slot;

[0015] The buckle is a sheet-like structure with a protruding portion, and the lower half of the sheet-like structure has a notch;

[0016] Both sides of the clamping slot are provided with clamping openings matching the protruding portion of the clamping buckle, and the width of the clamping buckle is smaller than the diameter of the clamping openings.

[0017] The fuse body includes a slot body plug-in part, a first arc extinguishing cavity, a second arc extinguishing cavity and a fuse; there are two first arc extinguishing cavities and two slot body plug-in parts, the two ends of the second arc extinguishing cavity are connected to the first arc extinguishing cavity, and the first arc extinguishing cavity is connected to the slot body plug-in part; the fuse passes through the first arc extinguishing cavity and the second arc extinguishing cavity and is connected to the slot body plug-in part.

[0018] The first arc extinguishing cavity and the second arc extinguishing cavity are both sealed structures and are filled with different arc extinguishing materials.

[0019] It also includes a pull ring connected to the outer wall of the upper base plate.

[0020] The present invention has the following advantages and beneficial effects:

[0021] 1. The present invention has a fast and clean fusing capability, and can meet the developer's requirements for multiple fuses or multi-stage fusing with different fusing currents in parallel. In addition, the fuse element can be replaced without soldering the PCB each time. At the same time, it has multiple arc extinguishing devices. Therefore, the fuse has high performance and strong reliability, meets various R&D needs, reduces R&D costs, shortens R&D time, and brings convenience to R&D and product application.

[0022] 2. The present invention adopts a structural method in which the fuse welding part and the fuse replacement part are separated. The welding part is always welded to the PCB board and no longer needs to be replaced. Only the fuse body is replaced, which realizes the replaceable feature of the fuse, prolongs the service life of the PCB, improves the applicability of the fuse, increases the operability of the fuse, and makes the circuit construction simple and reliable, and easy to operate.

[0023] 3. The present invention adopts different types of fuse body structures, realizing one or more fuse elements in one fuse, which is conducive to the parallel use of fuses or multi-stage use of different fusing currents, improves the simplicity of circuit use, increases the convenience of research and development, and reduces the application space of PCB.

[0024] 4. The fuse welding part and the fuse replacement part of the present invention adopt a conical contact form, and locking structures are added on both sides to ensure effective contact between the two parts and improve the reliability of the fuse.

[0025] 5. The fuse welding part and fuse replacement part of the present invention adopt an oblique insertion mode and an elastic element to ensure the locking of the two parts, enhance the transportation performance of the fuse, increase the adaptability of the entire product to mechanical environments, and improve the stability of the fuse.

[0026] 6. The present invention adopts a structure of two arc extinguishing chambers, each containing different arc extinguishing materials, which ensures that the fuse is quickly and cleanly blown, improves the protection characteristics of the circuit, and increases the safety performance of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the overall structure of the fuse of the present invention;

[0028] Figure 2 It is a side structural diagram of the fuse of the present invention;

[0029] Figure 3 This is an overall structural diagram of the fuse replacement part of the present invention;

[0030] Figure 4 It is a top sectional view of the replaceable part of the fuse of the present invention;

[0031] Figure 5 A cross-sectional view of a fuse welding portion of the present invention;

[0032] Figure 6 A structural diagram of an elastic element inside the fuse of the present invention;

[0033] Figure 7 This is a structural diagram of the lock inside the fuse of the present invention;

[0034] Figure 8 A structural diagram of a metal slot inside a fuse of the present invention;

[0035] Figure 9 This is a structural diagram of the fuse body inside the fuse of the present invention.

[0036] Among them, 1 is the upper base plate, 2 is the lower base plate, 3 is the first end face electrode, 4 is the second end face electrode, 5 is the fuse replacement part, 6 is the elastic element, 7 is the lock, 7-1 is the buckle, 7-2 is the slot, 8 is the metal slot, 9 is the fuse body, 9-1 is the slot body connection part, 9-2 is the first arc extinguishing cavity, 9-3 is the second arc extinguishing cavity, 9-4 is the fuse wire, 10 is the pull ring, and 11 is the fuse welding part. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1As shown, a chip fuse for a switching power supply includes a fuse replacement part 5 and a fuse welding part 11; the fuse replacement part 5 includes an upper base plate 1, a fuse body 9 and a buckle of a lock 7; there are several fuse bodies 9, which are fixedly installed in the inner cavity of the upper base plate 1; the slot plug-in part of the fuse body 9 is exposed at the lower part of the upper base plate 1; the buckle of the lock 7 is connected to the lower part of the upper base plate 1; the fuse welding part 11 includes a lower base plate 2, a first end surface electrode 3, a second end surface The electrode 4, the metal slot 8 and the card slot of the lock buckle 7; the first end surface electrode 3 and the second end surface electrode 4 are respectively fixed to the left and right ends of the lower substrate 2, and are fully or partially exposed to the lower substrate 2; the metal slot 8 is arranged on the upper part of the lower substrate 2, and the number and size correspond to the fuse body 9, and is used to plug into the slot body connecting part of the fuse body 9; the card slot of the lock buckle 7 is connected to the upper part of the lower substrate 2, corresponding to the card buckle of the lock buckle 7; the upper substrate 1 is connected to the lower substrate 2 through the lock buckle 7.

[0039] The upper base plate 1 is connected to the pull ring 10. The fuse body 9 is embedded or installed in the cavity of the upper base plate 1, with the slot connector 9-1 exposed outside the upper base plate 1. The latch 7 is connected to the upper base plate 1. The lower base plate 2 is connected to the first end surface electrode 3 and the second end surface electrode 4, and is also connected to the latch 7's slot. The elastic element 6 and the metal slot 8 are installed or embedded in the cavity of the lower base plate 2.

[0040] The upper substrate 1 can be formed by cold pressing or hot pressing the raw materials into the required contact surfaces except the bottom cover plate through a forming mold with a specific shape, and then solidified into shape; or the material can be solidified first and then the cavity can be realized by etching or machining. If necessary, a heat-insulating filler can be added to the cavity, and the volume of the filler must take into account the movement trajectory of the fuse body 9. The bottom cover plate of the upper substrate 1 needs to be processed into a protrusion with a triangular cone shape, and at the same time, the bottom cover plate needs to be made into a circular opening according to the number of fuse bodies 9. Ensure close integration with the fuse body 9. The upper substrate 1 mainly includes Figure 1 The six cover plates shown are arranged in a cavity, or a solid cavity with inner wall filling. The inner wall filling ensures sufficient space for the fuse body 9. The upper base plate 1 primarily secures and protects the fuse body 9, preventing it from being hit by foreign objects and improving its performance and lifespan.

[0041] The lower substrate 2 can be formed by cold pressing or hot pressing the raw material into the required contact surface outside the upper cover through a forming mold with a specific shape, and then solidifying it into shape; alternatively, the material can be solidified first and then the cavity can be realized by etching or machining. If necessary, heat-insulating fillers can be added to the cavity. The upper cover needs to be processed into a triangular pyramidal groove that is combined with the bottom cover of the upper substrate. At the same time, the circular opening that matches it is processed according to the number of metal slots 8 to ensure the combination of the upper and lower parts of the fuse. The lower substrate 2 includes Figure 1 The six facets shown are front, back, left, right, top, and bottom. These six facets form a cavity or a solid cavity with inner wall filling. The lower substrate 2 primarily serves as a carrier for the first and second end electrodes 3, 4, securing and supporting them. Like the upper substrate 1, the lower substrate 2 can be a cavity with either a hollow cavity or an inner wall filling, but space must be maintained for the elastic element 6 and metal slot 8.

[0042] The first end surface electrode 3 and the second end surface electrode 4 are formed into a thin metal layer on the front, rear, left, and right cover plates of the lower substrate 2 by laminating or sputtering a metal copper sheet, and then the surface end electrodes are etched into the metal layer according to the required size. The first end surface electrode 3 and the second end surface electrode 4 can be wrapped around the front, rear, left, and right cover plates, or embedded in the front, rear, left, and right cover plates. The first end surface electrode 3 and the second end surface electrode 4 are mainly used for soldering to the pads of the PCB. This ensures that the fuse and the PCB can be effectively combined.

[0043] like Figure 3 As shown, the fuse replacement unit 5 mainly includes an upper base plate 1, a latch portion of a lock catch 7, a fuse body 9, and a pull ring 10. It is primarily used to replace the fuse's fuse element. Fusing elements with different breaking currents can be replaced as needed. This makes the fuse replaceable, improves the fuse's applicability, and enhances its operability.

[0044] like Figure 6 As shown, the elastic element 6 is installed next to the oblique slot of the fuse welding portion 11. The elastic force and deformation of the elastic element 6 secure and lock the oblique slot. The number of elastic elements is an even number. This design improves the fit between the fuse welding portion 11 and the fuse replacement portion 5, enhances the stability of the fuse, ensures effective contact at all points, and strengthens the reliability of the fuse. It also increases the overall product's suitability for mechanical environments.

[0045] like Figure 7As shown, the lock 7 mainly includes a buckle 7-1 and a slot 7-2. The buckle 7-1 is designed to be a sheet with a protruding part, and the lower half of the sheet of the buckle 7-1 is made into a shape with a notch. The slot 7-2 is processed to have a bayonet on both sides that matches the protruding part of the buckle 7-1, and the volume (width) of the buckle sheet is slightly smaller than the diameter of the bayonet. When the buckle 7-1 is inserted downward, the protruding part is stuck to the bayonet to ensure locking; when separating, press the protruding part with one hand and pull the pull ring 10 with the other hand to separate them. The lock 7 is made of insulating and heat-insulating material, and mainly adopts the design of plug-in buckle locking, which cooperates with the elastic element 6 to ensure that the replacement part and the welding part of the fuse are in good contact and locked, ensuring that the replacement part of the fuse does not move during use, thereby improving the safety and reliability of the fuse.

[0046] like Figure 8 As shown, the metal slot 8 is a conical metal slot body, which is cast by a forming mold to ensure the smoothness of the slot body. It has the following two main functions: (1) It facilitates the quick and accurate insertion of the slot body plug-in portion 9-1 of the fuse body 9 into the slot; (2) It facilitates the effective contact between the fuse welding portion 11 and the fuse replacement portion 5, ensuring point-to-point contact and improving the stability of the fuse.

[0047] like Figure 9 As shown, the fuse body 9 includes a slot connector 9-1, a first arc-extinguishing cavity 9-2, a second arc-extinguishing cavity 9-3, and a fuse 9-4. The fuse 9-4 passes through the first arc-extinguishing cavity 9-2 and the second arc-extinguishing cavity 9-3. The first arc-extinguishing cavity 9-2 is connected to the second arc-extinguishing cavity 9-3, the second arc-extinguishing cavity 9-3 is connected to the slot connector 9-1, and the slot connector 9-1 is connected to the fuse 9-4. The first arc-extinguishing cavity 9-2 and the second arc-extinguishing cavity 9-3 are made of insulating and heat-insulating materials and are relatively sealed. The slot connector 9-1 is a metal conductor. The fuse body 9 allows one or more fuses to be contained within a single fuse, facilitating the parallel use of fuses or the multi-stage use of fuses with different breaking currents, thereby simplifying the circuit. The fuse body 9 adopts a structure of two arc extinguishing cavities, namely the first arc extinguishing cavity 9-2 and the second arc extinguishing cavity 9-3, which are respectively filled with different arc extinguishing materials, ensuring that the fuse melts quickly and cleanly, improving the protection characteristics of the circuit and increasing the safety performance of the circuit.

[0048] The pull ring 10 is used for transporting or replacing the replacement part of the fuse, which is beneficial to protecting other structures of the replacement part of the fuse and improving the convenience of replacement.

[0049] like Figure 5As shown, the fuse welding part 11 includes the lower substrate 2, the first end surface electrode 3, the second end surface electrode 4, the elastic element 6, the slot part of the lock 7 and the metal slot 8, which ensures that the fuse welding part 11 is always welded to the PCB board and does not need to be replaced. Only the fuse body part needs to be replaced, thereby increasing the service life of the PCB and reducing the cost of research and development.

[0050] like Figure 2 、 4 5, the fuse body can be a fuse replacement part 5 containing only a slot plug part 9-1 and a fuse welding part of a metal slot 8 ( Figure 2 (b)), or two ( Figure 2 (c)), or three ( Figure 2 (a)), or even multiple. The overall composition of the fuse depends on the specific application scenario; at the same time, the small value of the slot body plug-in part 9-1 of the fuse replacement part 5 can be plugged into the metal slot 8 of the fuse welding part 11 that is greater than or equal to this value. For example, a fuse replacement part with two slot body plug-in parts can be plugged into a fuse welding part with two, three, or even more metal slots. This design facilitates fuse replacement, improves the universal performance of the fuse, ensures the rapidity of testing and maintenance, and reduces R&D costs.

[0051] The processing flow of the fuse of the present invention is as follows:

[0052] (1) Process the upper base plate except the bottom cover plate according to the number of fuse bodies, and process the bottom cover plate;

[0053] (2) Process the lower substrate except the top cover plate according to the number of metal slots, process the top cover plate, and electroplate or embed the end surface electrodes;

[0054] (3) Processing pull rings, lock buckles, metal slots, fuse bodies, and elastic elements;

[0055] (4) Add fillers to the upper and lower substrates as needed, ensuring that the shape of the fillers is consistent with the metal slot 8 and the fuse body 9;

[0056] (5) Install the pull ring, the buckle of the lock, and the fuse body in the corresponding position of the upper base plate, and finally install the bottom cover of the upper base plate to form the fuse replacement part;

[0057] (6) Install the lock slot, elastic element, and metal slot at the corresponding position of the lower base plate, and finally install the top cover of the lower base plate to form the fuse welding part.

[0058] There is no order for the steps (1), (2), and (3). Except for the fuse, the metal slot, the end face electrode, the elastic element, and the slot body connection part, the rest are made of insulating and heat-insulating materials.

Claims

1. A chip fuse used in a switching power supply, characterized in that: Including fuse replacement part and fuse welding part; The fuse replacement part includes an upper base plate, a fuse body, and a lock buckle; the fuse body is provided in a plurality and fixedly mounted in the inner cavity of the upper base plate; the slot body connecting portion of the fuse body is exposed at the lower portion of the upper base plate; the lock buckle is connected to the lower portion of the upper base plate; The fuse welding portion includes a lower base plate, a first end surface electrode, a second end surface electrode, a metal slot, and a locking slot of a lock buckle; the first end surface electrode and the second end surface electrode are respectively fixed to the left and right ends of the lower base plate and are fully or partially exposed from the lower base plate; the metal slots are arranged on the upper part of the lower base plate, and the number and size correspond to the fuse body, and are used to plug into the slot body plug-in part of the fuse body; the locking slot of the lock buckle is connected to the upper part of the lower base plate and corresponds to the locking buckle of the lock buckle; The upper substrate is connected to the lower substrate via the lock; The fuse body includes a slot body plug-in part, a first arc extinguishing cavity, a second arc extinguishing cavity and a fuse; there are two first arc extinguishing cavities and two slot body plug-in parts, the two ends of the second arc extinguishing cavity are connected to the first arc extinguishing cavity, and the first arc extinguishing cavity is connected to the slot body plug-in part; the fuse passes through the first arc extinguishing cavity and the second arc extinguishing cavity and is connected to the slot body plug-in part.

2. A chip fuse for a switching power supply according to claim 1, characterized in that: The upper base plate includes an integrally formed upper cover plate, a left cover plate, a right cover plate, a front cover plate and a rear cover plate, and also includes a bottom cover plate, which connects the left cover plate, the right cover plate, the front cover plate and the rear cover plate; the middle part of the bottom cover plate has a triangular cone-shaped protrusion from the front cover plate to the rear cover plate, and is also provided with a circular opening corresponding to the fuse body.

3. A chip fuse for a switching power supply according to claim 2, characterized in that: The lower base plate includes an integrally formed left cover plate, a right cover plate, a front cover plate, a rear cover plate and a bottom cover plate, and also includes an upper cover plate, the upper cover plate is provided with a triangular pyramidal groove corresponding to the raised portion of the bottom cover plate, and is also provided with an opening corresponding to the circular opening, and the metal slot is arranged in the opening.

4. A chip fuse for a switching power supply according to claim 3, characterized in that: It also includes an even number of elastic elements, one end of each of which is connected to the inner wall of the left cover plate / the right cover plate, and the other end of each of which is connected to the triangular pyramidal groove.

5. The chip fuse for use in a switching power supply according to claim 1, wherein: The lock buckle includes a buckle and a slot; The buckle is a sheet-like structure with a protruding portion, and the lower half of the sheet-like structure has a notch; Both sides of the clamping slot are provided with clamping openings matching the protruding portion of the clamping buckle, and the width of the clamping buckle is smaller than the diameter of the clamping openings.

6. The chip fuse for use in a switching power supply according to claim 1, wherein: The first arc extinguishing cavity and the second arc extinguishing cavity are both sealed structures and are filled with different arc extinguishing materials.

7. The chip fuse for a switching power supply according to claim 1, characterized in that: It also includes a pull ring connected to the outer wall of the upper base plate.

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