A fuse

Abstract

The utility model provides a kind of fuse, comprising: shell, base, fusible body, two leads, two leads respectively pass through base and extend after upper surface of base, and with fusible body both ends welding, shell covers in the upper of base, fusible body is located between shell and base, fusible body includes fusible body silk and support pipe, fusible body silk is wound on support pipe, the winding interval of fusible body silk at the both ends of support pipe is less than the winding interval in support pipe middle, two leads are respectively welded on the both ends portion of fusible body silk winding interval small. By the above structure, the fusible body of the utility model can improve the weldability of the fusible body in the fuse, avoid false welding, and improve product reliability.

Description

Technical Field

[0001] This utility model relates to the technical field of circuit overcurrent protection devices, and more specifically to a fuse. Background Technology

[0002] A fuse is an electrical device that breaks the circuit by melting a fusible element when the current exceeds a specified value, thus protecting the circuit itself.

[0003] Existing fuses consist of a housing, a base, and a fusible element, with both ends of the fusible element welded to the base by leads. The fusible element typically comes in two forms: monofilament and wound. Monofilament fusible elements are single filaments, requiring manual welding to the leads, resulting in low production efficiency. Wound fusible elements, on the other hand, have the fusible element filament wound around a fiberglass tube, allowing for automated welding. Furthermore, with the same resistance, the diameter of the wound fusible element filament can be larger than that of the monofilament, enabling the fusible element to carry a larger instantaneous current and making it less prone to melting upon energization compared to the monofilament. However, when the fusible element is wound around the fiberglass tube, it is difficult to avoid large gaps between each turn, resulting in a small contact area between the lead end and the fusible element during lead welding. This leads to poor solder bonding, resulting in both incomplete soldering and difficulty in soldering. Utility Model Content

[0004] The purpose of this invention is to provide a fusible element that improves the weldability of the fusible element in the fuse, avoids incomplete soldering, and improves product reliability.

[0005] To achieve the above objectives, this utility model provides a fuse, comprising: a housing, a base, a fusible element, and two leads. The two leads pass through the base and extend beyond the upper surface of the base, and are then welded to both ends of the fusible element. The housing covers the base, and the fusible element is located between the housing and the base. The fusible element includes a fusible wire and a support tube. The fusible wire is wound around the support tube, and the winding spacing of the fusible wire at both ends of the support tube is smaller than the winding spacing in the middle of the support tube. The two leads are respectively welded to the two ends of the fusible wire with the smaller winding spacing.

[0006] Furthermore, the winding spacing of the fusible wire at the middle of the support tube is L, and the winding spacing of the fusible wire at both ends of the support tube is L / n, where n>1.

[0007] Furthermore, the base and the housing are connected by a snap-fit ​​mechanism. At least two protruding ridges are provided on each of the two sides of the base, and grooves are provided on the inner walls of both sides of the housing corresponding to each protruding ridge. When the base and the housing are connected, the protruding ridges are engaged in the grooves.

[0008] Furthermore, each protruding ridge has a notch at its end. The ends of adjacent protruding ridges on the same side of the base with notches are located on different sides. When the base is connected to the housing, the notches on the same connecting surface form a non-linear exhaust channel between the base and the housing.

[0009] Furthermore, two protruding ridges are provided on each side of the base, and two grooves are provided on each side of the inner wall of the shell. The ends of the two protruding ridges are notched, and the ends of the two protruding ridges with notches are located on different sides.

[0010] Furthermore, three protruding ridges are provided on each of the two sides of the base, and three grooves are provided on the inner walls of each of the two sides of the shell. The ends of the three protruding ridges are notched, and the ends of adjacent protruding ridges with notches are located on different sides. When the base is connected to the shell, the notches on the same connection surface form an S-shaped exhaust channel between the base and the shell.

[0011] Furthermore, the portion of the lead wire protruding from the upper end of the base forms an upper lead segment. The upper end of the upper lead segment is flattened and bent to wrap around both ends of the fusible body, and then welded and fixed to the fusible body.

[0012] Furthermore, the shell is filled with an arc-quenching material, which is quartz sand.

[0013] Furthermore, the support tube is a glass fiber tube.

[0014] By adopting the above solution, the fusible element of this utility model can increase the contact area with the lead wire while ensuring the electrical characteristics requirements of the product, thereby improving the solderability of the fusible element in the fuse, avoiding false soldering, and improving the reliability of the product.

[0015] Furthermore, by creating a non-linear venting channel between the base and the housing, the fuse can expel a large amount of gas when encountering abnormally high voltage or current. This prevents excessive internal pressure from causing the housing to explode or arcing, ensuring safety. Also, by not placing the notch at the same end of the protruding ridge, making the venting channel non-linear, it prevents direct arcing and avoids any metallic impurities in the exhaust gas from being ejected directly from a straight venting channel, thus preventing damage to the circuit board. Attached Figure Description

[0016] Figure 1 This is a perspective view of the first embodiment of the present utility model.

[0017] Figure 2 This is an exploded view of the first embodiment of the present invention.

[0018] Figure 3This is a cross-sectional view of the first embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the fusible wire structure of the first embodiment of this utility model.

[0020] Figure 5 This is a perspective view of the second embodiment of the present invention (with the shell removed).

[0021] Figure 6 This is a cross-sectional view of the second embodiment of the present invention.

[0022] Figure 7 This is a diagram showing the internal structure of the plastic shell according to the second embodiment of this utility model.

[0023] Explanation of icon numbers:

[0024] 1. Casing; 11. Grooves;

[0025] 2 bases; 21 protruding ridges; 211 notches;

[0026] 3. Fusible material; 31. Fusible wire; 32. Support tube;

[0027] 4 leads; 41 upper pin segment. Detailed Implementation

[0028] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0029] See Figures 1 to 4 This is the first embodiment of the present invention. The fuse of the first embodiment includes: a housing 1, a base 2, a fusible element 3, and two leads 4. The two leads 4 pass through the base 2 and extend out of the upper surface of the base 2, and are welded to both ends of the fusible element 3. The housing 1 covers the base 2. The fusible element 3 is located between the housing 1 and the base 2. The fusible element 3 includes a fusible wire 31 and a support tube 32. The fusible wire 31 is wound around the support tube 32. The winding spacing of the fusible wire 31 at both ends of the support tube 32 is smaller than the winding spacing in the middle of the support tube 32. The two leads 4 are respectively welded to the two ends of the fusible wire 31 with the smaller winding spacing.

[0030] In the above embodiment, the fusible wire 31 is wound around the support tube 32 to form the fusible body 3. Therefore, this embodiment has the advantages of the wound fusible body 3 mentioned in the background art, that is, it can be automatically welded by equipment. Compared with the single-wire fusible body 3, the production efficiency is higher. Moreover, this embodiment can pass a larger instantaneous current, and it is less likely to melt at the moment of energization compared with the single-wire form.

[0031] Based on this, this embodiment further changes the winding spacing of the fusible wire 31 at both ends of the support tube 32, making dense winding at the connection with the lead wire 4 and normal winding in the middle part. This can increase the contact area between the fusible element 3 and the lead wire 4 while ensuring the electrical characteristics requirements of the product, thereby improving the solderability of the fusible element 3 in the fuse, avoiding false soldering, improving the reliability of the product, and solving the defects of the wound fusible element 3 in the prior art.

[0032] It should be noted that the fusible element 3 dissipates heat primarily through its ends during operation; that is, in this embodiment, heat is dissipated through the two ends of the fusible wire 31 with smaller winding spacing. In this embodiment, in the middle section with larger winding spacing, the fusible wire 31 can only dissipate heat through air or conduction to the two ends. However, since it is installed inside the housing 1, air cooling efficiency is low. The two ends of the fusible wire 31 with smaller winding spacing will also preferentially conduct heat away through the wires due to direct contact with the wires and solder. Furthermore, because the ends are soldered with wires and solder, the impedance of the two ends of the fusible wire 31 with smaller winding spacing is lower, and heat accumulation is not as fast as in the middle section. As a result, the heat dissipation efficiency of the fusible wire 31 in the middle section with larger winding spacing is lower than that in the two ends with smaller winding spacing. Therefore, when it melts, the fusible wire 31 will still melt first in the middle section, rather than at the two ends where the windings are more dense.

[0033] Preferably, in this embodiment, the winding spacing of the fusible wire 31 at the middle of the support tube 32 is L, and the winding spacing of the fusible wire 31 at both ends of the support tube 32 is L / n, where n>1.

[0034] In this embodiment, the shell 1 is filled with an arc-extinguishing material, which is quartz sand. The support tube 32 is a glass fiber tube. The part of the lead wire 4 that protrudes from the upper end of the base 2 forms an upper lead segment 41. The upper end of the upper lead segment 41 is flat and bent and wrapped around both ends of the fusible body 3, and is welded and fixed to the fusible body 3.

[0035] In the first embodiment, the base 2 and the housing 1 are connected by a snap-fit ​​mechanism. Two protruding ridges 21 are provided on each of the two side surfaces of the base 2, and grooves 11 are provided on the inner walls of both sides of the housing 1 corresponding to each protruding ridge 21. When the base 2 and the housing 1 are connected, the protruding ridges 21 engage within the grooves 11. In other embodiments, there may be more than two protruding ridges 21, thereby ensuring a tight and stable connection between the base 2 and the housing 1 in this embodiment.

[0036] In addition, in other embodiments, notches 211 may be provided at the ends of each protruding ridge 21. The ends of adjacent protruding ridges 21 with notches 211 on the same side of the base 2 are located on different sides. That is, if the notch of the previous protruding ridge 21 is located on the left end, the notch of the next protruding ridge 21 is located on the right end. When the base 2 is connected to the housing 1, the notches 211 on the same connecting surface form a non-linear exhaust channel between the base 2 and the housing 1. For example, when two protruding ridges 21 are provided on each of the two sides of the base 2, two grooves 11 are provided on the inner walls of both sides of the housing 1, and the ends of the two protruding ridges 21 with notches 211 are located on different sides. If high-pressure gas is generated inside the fuse housing 1 at this time, taking one of the connection surfaces between the housing 1 and the base 2 as an example, the gas will rush out from the gap 211 of the upper protrusion 21 on the connection surface, turn and pass through the gap between the two protrusions 21, turn again, and then exit the housing 1 through the gap 211 of the lower protrusion 21.

[0037] See Figures 5 to 7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment lies only in that three protruding ridges 21 are provided on each of the two side surfaces of the base 2, and three grooves 11 are provided on each of the two inner walls of the housing 1. Each of the three protruding ridges 21 has a notch 211 at its end, and the ends of adjacent protruding ridges 21 with notches 211 are located on different sides. When the base 2 is connected to the housing 1, the notches 211 on the same connecting surface form an S-shaped exhaust channel between the base 2 and the housing 1. In the second embodiment, when exhaust is required, the gas will make multiple turns on the connecting surface between the housing 1 and the base 2, sequentially passing through the notch 211 of the first protruding ridge 21, the gap between the first and second protruding ridges 21, the notch 211 of the second protruding ridge 21, the gap between the second and third protruding ridges 21, and the notch 211 of the third protruding ridge 21, thus exiting the housing 1 after following an S-shaped route.

[0038] The aforementioned structure, by forming a non-linear exhaust channel between the base 2 and the housing 1, allows the fuse to expel a large amount of gas when encountering abnormally high voltage or current. This prevents excessive internal pressure from causing the housing 1 to explode and be blown away, or from arc leakage, thus ensuring safety. Furthermore, by not placing the notch 211 at the same end of the protruding ridge 21, the exhaust channel is not linear, preventing direct arc ejection and avoiding damage to the circuit board from potentially metallic impurities mixed in with the exhaust gas that could be ejected directly from a linear exhaust channel.

[0039] The above are merely embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A fuse, characterized in that, include: The system comprises a housing, a base, a fusible element, and two leads. The two leads pass through the base and extend beyond the upper surface of the base before being welded to both ends of the fusible element. The housing covers the base, and the fusible element is located between the housing and the base. The fusible element includes a fusible wire and a support tube. The fusible wire is wound around the support tube. The winding spacing of the fusible wire at both ends of the support tube is smaller than the winding spacing in the middle of the support tube. The two leads are welded to the two ends of the fusible wire with the smaller winding spacing.

2. A fuse according to claim 1, characterized in that, The winding spacing of the fusible wire at the middle of the support tube is L, and the winding spacing of the fusible wire at both ends of the support tube is L / n, where n>1.

3. A fuse according to claim 1, characterized in that, The base and the shell are connected by a snap-fit ​​mechanism. At least two protruding ridges are provided on each of the two sides of the base. Corresponding grooves are provided on the inner walls of both sides of the shell. When the base and the shell are connected, the protruding ridges are engaged in the grooves.

4. A fuse according to claim 3, characterized in that, Each protruding ridge has a notch at its end. The ends of adjacent protruding ridges on the same side of the base with notches are located on different sides. When the base is connected to the housing, the notches on the same connecting surface form a non-linear exhaust channel between the base and the housing.

5. A fuse according to claim 4, characterized in that, The base has two raised ridges on each side, and two grooves on the inner walls of each side of the shell. The ends of the two raised ridges are notched, and the ends of the two raised ridges with notches are located on different sides.

6. A fuse according to claim 4, characterized in that, The base has three raised ridges on each of its two sides, and three grooves on the inner walls of each of its two sides. The ends of the three raised ridges are notched, and the ends of adjacent raised ridges with notches are located on different sides. When the base is connected to the shell, the notches on the same connection surface form an S-shaped exhaust channel between the base and the shell.

7. A fuse according to claim 1, characterized in that, The part of the lead wire protruding from the upper end of the base forms the upper lead segment. The upper end of the upper lead segment is flat and bent to wrap around both ends of the fusible body, and is welded and fixed to the fusible body.

8. A fuse according to claim 1, characterized in that, The shell is filled with arc-quenching material, which is quartz sand.

9. A fuse according to claim 1, characterized in that, The support tube is a fiberglass tube.

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