Method for manufacturing a tubular current fuse with integrated lead and fuse

Abstract

The present invention discloses a method for manufacturing a tubular current fuse with integrated lead and fuse. The tubular current fuse with integrated lead and fuse produced by the manufacturing method comprises an insulating shell, a first lead, a second lead and a fuse. The first lead, the second lead and the fuse are an integrated structure. The insulating shell is tubular, the fuse is located in the insulating shell, and the first lead and the second lead are respectively passed through two ends of the insulating shell. The first lead, the fuse and the second lead of the tubular current fuse with integrated lead and fuse of the present invention are an integrated structure. Compared with the traditional tubular current fuse with lead, the present invention not only does not have the problem of cold welding between the fuse and the electrode cap, or between the fuse and the lead, but also does not need to use solder connection, thereby reducing the cost of raw materials.

Description

Technical Field

[0001] The present invention relates to the field of circuit protection devices, and in particular to a method for manufacturing a tubular current fuse with an integrated lead and a fuse. Background Art

[0002] Tubular current fuses with leads, such as the 632 series and 520 series tubular fuse links, have a broad market application and are commonly used for overcurrent protection of household appliances (such as refrigerators, washing machines, and induction cookers), office equipment (such as printers, copiers, and shredders), communications equipment, and charging stations. Their structure generally consists of a melt, an insulating tube, solder, an electrode cap, and leads. The melt is placed inside the insulating tube, and the two ends of the melt are directly connected to the electrode caps through soldering. The electrode caps are then connected to the leads, and the electrode caps are wrapped around the two ends of the insulating tube to seal it. In order to improve the short-circuit breaking capacity, the insulating tube of some tubular current fuses is filled with arc-extinguishing media such as quartz sand. This type of tubular current fuse has the following two problems:

[0003] 1. There is a hidden danger of cold welding in the connection between the melt and the electrode cap;

[0004] 2. The need to use solder not only increases the cost, but also reduces its short-circuit breaking performance to a certain extent. Summary of the Invention

[0005] The present invention aims to provide a tubular current fuse with integrated leads and fuse element. Compared with conventional tubular current fuses with leads, the present invention not only eliminates the problem of cold solder joints between the fuse element and electrode cap, or between the fuse element and leads, but also eliminates the need for solder connections, reducing raw material costs and improving circuit interruption performance to a certain extent.

[0006] The present invention adopts the following technical solutions:

[0007] A tubular current fuse with an integrated lead and fuse comprises an insulating shell, a first lead, a second lead and a fuse. The first lead, the second lead and the fuse are an integrated structure. The insulating shell is tubular, the fuse is located in the insulating shell, and the first lead and the second lead extend from both ends of the insulating shell respectively.

[0008] Furthermore, the melt is flat and has at least one narrow neck, and a low-melting-point metal is provided on the surface of the melt, and the low-melting-point metal is located near the narrow neck, thereby forming an M-effect point.

[0009] Furthermore, the integrated structure consisting of the first lead, the second lead and the melt is made of a metal material with good electrical and thermal conductivity.

[0010] Furthermore, the integrated structure consisting of the first lead, the second lead and the melt is made of copper wire, or tinned copper wire, or silver-plated copper wire.

[0011] Furthermore, an arc extinguishing medium is provided around the melt inside the insulating shell.

[0012] Furthermore, the insulating shell is a circular ceramic tube with openings at both ends of the insulating shell, the opening at the second end is larger than the opening at the first end, the first lead wire and the melt pass through the insulating shell from the opening at the second end of the insulating shell, the opening at the first end of the insulating shell is smaller than the width of the melt, the first lead wire passes through the opening at the first end and the melt is blocked inside the insulating shell.

[0013] As a preferred solution, a positioning block is built into the opening at the second end of the insulating shell. The positioning block is a tubular ceramic positioning block. The outer diameter of the positioning block is smaller than the inner diameter of the opening at the second end of the insulating shell, and the inner diameter of the positioning block is larger than the outer diameter of the second lead. The second lead passes through the center hole of the positioning block and extends outward; the two ends of the insulating shell are sealed with sealant, and the sealant fixes the first lead and the second lead.

[0014] As another preferred embodiment, the first end and / or the second end of the insulating shell is sealed with a metal cap, which is a cylindrical metal cap. The metal cap wraps around the end of the insulating shell and forms an interference fit with the insulating shell. A through hole is provided at the bottom of the metal cap facing the opening of the insulating shell, and the first lead and / or the second lead passes through the through hole at the bottom of the metal cap.

[0015] The present invention also provides a method for manufacturing a tubular current fuse with an integrated lead and fuse, comprising the following steps:

[0016] 1) Lead and melt forming: The middle section of the round metal wire is rolled or stamped into a flat shape, and then the melt with one or more narrow necks is laser cut or punched out, thereby forming an integrated structure with leads at both ends and melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively;

[0017] 2) Melting point low melting point metal: Use a heating device to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck;

[0018] 3) Assembling the lead wire and the melt into the ceramic tube: inserting the first lead wire through the opening at the second end of the circular ceramic tube and then passing it out through the opening at the first end of the circular ceramic tube. The melt is located in the inner hole of the circular ceramic tube. The diameter of the opening at the first end of the circular ceramic tube is smaller than the width of the melt. The transition section between the melt and the first lead wire is clamped at the opening at the first end of the circular ceramic tube to achieve positioning. The second lead wire is exposed outside the opening at the second end of the circular ceramic tube.

[0019] 4) Filling the arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt;

[0020] 5) Assembling the insulating positioning block: The ceramic positioning block has a center hole. Pass the second lead through the center hole of the ceramic positioning block, and then press the ceramic positioning block into the opening of the second end of the circular ceramic tube;

[0021] 6) Sealing: Seal the first end and the second end of the circular ceramic tube with sealant.

[0022] The present invention also provides another method for manufacturing a tubular current fuse with an integrated lead and fuse, comprising the following steps:

[0023] 1) Assembling the first metal cap: Align the mouth of the first metal cap with the first end of the circular ceramic tube, and crimp the first metal cap around the first end of the circular ceramic tube to form an interference fit. The bottom of the first metal cap is provided with a through hole aligned with the opening of the first end of the circular ceramic tube;

[0024] 2) Lead and melt forming: The middle section of the round metal wire is rolled or stamped into a flat shape, and then the melt with one or more narrow necks is laser cut or punched out, thereby forming an integrated structure with leads at both ends and melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively;

[0025] 3) Melting point low melting point metal: Use a heating device to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck;

[0026] 4) Assembling the lead wire and melt into the ceramic tube: Insert the first lead wire through the second end opening of the circular ceramic tube, and then pass it through the first end opening of the circular ceramic tube and the through hole at the bottom of the first metal cap. The diameter of the first end opening of the circular ceramic tube is smaller than the width of the melt. The transition section between the melt and the first lead wire is clamped at the first end opening of the circular ceramic tube to achieve positioning;

[0027] 5) Filling the arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt;

[0028] 6) Assembling the second metal cap: A through hole is provided at the bottom of the second metal cap. The second lead is passed through the through hole at the bottom of the second metal cap. Then, the second metal cap is wrapped around the second end of the circular ceramic tube to form an interference fit with it.

[0029] The tubular current fuse with integrated lead and fuse element of the present invention has the following advantages:

[0030] 1. The first lead, fuse and second lead are integrated into one structure, which can avoid the hidden danger of cold welding between the lead and fuse in conventional tubular current fuses with leads.

[0031] 2. The melt is flat and is provided with one or more narrow necks. When the short circuit is disconnected, the multiple narrow necks can cut the short circuit arc into multiple segments, thereby improving the short circuit breaking capacity.

[0032] 3. A low-melting-point metal is placed on the melt surface next to the narrow neck of the fuse. The narrow neck has high resistance, and when overloaded, the narrow neck heats up, melting the adjacent low-melting-point metal and attracting it to the narrow neck, forming an M-effect point. This causes the narrow neck to melt and break, reducing its melting temperature rise. By placing low-melting-point metals with different melting points, the M-effect point can be opened at different temperatures, adjusting its melting temperature and reducing the potential high-temperature risks when the fuse is overloaded.

[0033] 4. The opening at the second end of the circular ceramic tube is slightly larger than the diameter of the second lead wire, allowing the second lead wire to pass through the center. A ceramic positioning block is provided at the first end of the circular ceramic tube, allowing the first lead wire to be led out from the center of the first end of the circular ceramic tube. This not only forms a symmetrical structure, which is convenient for customer installation, but the presence of the positioning block can also prevent the arc from being ejected during a short circuit, thereby improving the short-circuit breaking performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the external structure of a tubular current fuse with integrated lead and fuse element according to Example 1 of the present invention is shown;

[0035] Figure 2 A cross-sectional view of a tubular current fuse with integrated lead and fuse element according to Example 1 of the present invention is shown;

[0036] Figure 3 A schematic top view of the melt of Example 1 of the present invention is shown;

[0037] Figure 4 A schematic front view of the melt of Example 1 of the present invention is shown;

[0038] Figure 5 A schematic diagram of the external structure of a tubular current fuse with integrated lead and fuse element according to Example 2 of the present invention is shown;

[0039] Figure 6 A cross-sectional view of a tubular current fuse with integrated lead and fuse element according to a second embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] To further illustrate various embodiments, the present invention is provided with accompanying drawings. These drawings form part of the present disclosure and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, one of ordinary skill in the art will understand other possible embodiments and the advantages of the present invention. The components in the figures are not drawn to scale, and similar reference numerals are generally used to represent similar components.

[0041] Example 1:

[0042] like Figures 1 to 4 As shown, a tubular current fuse with integrated leads and fuse includes an insulating shell 3, a first lead 1-2, a second lead 1-1 and a fuse 1-3. The first lead 1-2, the second lead 1-1 and the fuse 1-3 are an integrated structure. The insulating shell 3 is tubular, the fuse 1-3 is located in the insulating shell 3, and the first lead 1-2 and the second lead 1-1 respectively extend from both ends of the insulating shell 3.

[0043] like Figure 3 and Figure 4 As shown, the melt 1-3 is flat, and the thickness of the melt 1-3 is set according to different current specifications. The melt 1-3 has one or more narrow necks 1-3-1. Figure 2 、 Figure 3 and Figure 4 An example of a melt 1-3 having multiple narrow necks 1-3-1 is shown in FIG. The surface of the melt 1-3 is provided with a low melting point metal 4, such as Figure 2 As shown, the low-melting-point metal 4 is located near the narrow neck 1-3-1, thereby forming an M-effect point. The low-melting-point metal 4 can be made of metals with different melting points, such as Sn, SnCu alloy, and SnAgCu, which helps reduce the fuse's melting temperature rise when it blows due to overload. It is worth noting that the narrow neck 1-3-1 is preferably located away from the intersection of the fuse 1-3 and the first lead 1-2 or the second lead 1-1.

[0044] The integrated structure consisting of the first lead 1-2, the second lead 1-1, and the melt 1-3 is made of a metal material with good electrical and thermal conductivity. For example, the integrated structure consisting of the first lead 1-2, the second lead 1-1, and the melt 1-3 can be made of copper wire, or tinned copper wire, or silver-plated copper wire, which can be obtained by flattening the middle section of these round metal wires.

[0045] like Figure 2 As shown, an arc extinguishing medium 5 is provided around the melt 1 - 3 inside the insulating shell 3 , and the arc extinguishing medium 5 can be a medium with good arc extinguishing effect such as quartz sand.

[0046] The insulating shell 3 can be a tubular object made of insulating materials such as ceramic or glass, and can be a square tube or a round tube. This embodiment takes the insulating shell 3 as a round ceramic tube as an example for detailed description.

[0047] like Figure 2As shown, the insulating shell 3 has openings at both ends, with the second end opening being larger than the first end opening. The first end opening is preferably configured in a tapered shape. The first lead wire 1-2 and the fuse 1-3 pass through the insulating shell 3 through the second end opening. The diameter of the first end opening of the insulating shell 3 is smaller than the width of the fuse 1-3. The first lead wire 1-2 passes through the first end opening while the fuse 1-3 is blocked inside the insulating shell 3. The transition section between the first lead wire 1-2 and the fuse 1-3 is stuck on the tapered surface at the first end opening of the insulating shell, allowing the first lead wire 1-2 to pass through the center of the first end of the insulating shell 3. The diameter of the first end opening of the insulating shell 3 is slightly larger than the outer diameter of the first lead wire 1-2, which facilitates the first lead wire 1-2 to pass through the first end of the insulating shell 3.

[0048] like Figure 2 As shown, a positioning block 6 is built into the opening of the second end of the insulating shell 3. The positioning block 6 is a tubular ceramic positioning block. The outer diameter of the positioning block 6 is slightly smaller than the inner diameter of the opening of the second end of the insulating shell 3, and the inner diameter of the positioning block 6 is slightly larger than the outer diameter of the second lead 1-1. The second lead 1-1 passes through the center hole of the positioning block 6 and extends outward. The positioning block 6 allows the second lead 1-1 to pass through the center of the second end of the insulating shell 3.

[0049] like Figure 2 As shown, both ends of the insulating shell 3 are sealed with sealant 2, which fixes the first lead 1-2 and the second lead 1-1. The sealant 2 can be an insulating material with good sealing properties such as epoxy resin, silicone resin, silicone rubber, etc.

[0050] Example 2:

[0051] The difference between this embodiment and embodiment 1 is that a metal cap is used to seal the opening of the insulating shell 3 instead of the sealant 2 in embodiment 1. Specifically:

[0052] like Figure 5 and Figure 6 As shown, the first end of the insulating shell 3 is sealed with a first metal cap 7-2. The first metal cap 7-2 is a cylindrical metal cap. The first metal cap 7-2 wraps the first end of the insulating shell 3 and forms an interference fit with the insulating shell 3. A circular through hole is provided at the bottom of the first metal cap 7-2 facing the opening of the first end of the insulating shell 3. The diameter of the circular through hole is slightly larger than the diameter of the first lead 1-2. The first lead 1-2 passes through the through hole at the bottom of the first metal cap 7-2 and is connected to the first metal cap 7-2 to form the first lead 1-2 of the fuse.

[0053] like Figure 5 and Figure 6As shown, the second end of the insulating shell 3 is sealed with a second metal cap 7-1. Second metal cap 7-1 is a cylindrical metal cap with a circular through-hole at its bottom. The diameter of the circular through-hole is slightly larger than the diameter of the second lead 1-1. Second lead 1-1 passes through the through-hole at the bottom of second metal cap 7-1 and is connected to second metal cap 7-1. Second metal cap 7-1 wraps around the second end of the insulating shell 3 and forms an interference fit with it.

[0054] The circular through holes of the first metal cap 7-2 and the second metal cap 7-1 are both located in the center of the end surface of the insulating shell 3, ensuring that the first lead 1-2 and the second lead 1-1 pass through the center.

[0055] Example 3:

[0056] This embodiment provides a method for manufacturing a tubular current fuse with integrated leads and fuse element, which is used to manufacture the tubular current fuse with integrated leads and fuse element as described in Example 1, comprising the following steps:

[0057] 1) Lead and melt forming: The middle section of a round metal wire (e.g., tinned copper wire) is rolled or stamped into a flat shape, and then laser cut or punched out a melt with one or more narrow necks, thereby forming an integrated structure with leads at both ends and a melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively.

[0058] 2) Melting point of low melting point metal: Use a heating device, such as an electric soldering iron, to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck;

[0059] 3) Assembling the lead wire and the melt into the ceramic tube: inserting the first lead wire through the opening at the second end of the circular ceramic tube and then passing it out through the opening at the first end of the circular ceramic tube. The melt is located in the inner hole of the circular ceramic tube. The diameter of the opening at the first end of the circular ceramic tube is smaller than the width of the melt. The transition section between the melt and the first lead wire is clamped at the opening at the first end of the circular ceramic tube to achieve positioning. The second lead wire is exposed outside the opening at the second end of the circular ceramic tube.

[0060] 4) Filling the arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt;

[0061] 5) Assembling the insulating positioning block: The ceramic positioning block has a center hole. Pass the second lead through the center hole of the ceramic positioning block, and then press the ceramic positioning block into the opening of the second end of the circular ceramic tube;

[0062] 6) Sealing: Seal the first end and the second end of the circular ceramic tube with sealant.

[0063] Example 4:

[0064] This embodiment discloses a method for manufacturing a tubular current fuse with integrated leads and fuse element, which is used to manufacture the tubular current fuse with integrated leads and fuse element described in Example 2, including the following steps:

[0065] 1) Assembling the first metal cap: Align the mouth of the first metal cap with the first end of the circular ceramic tube, and crimp the first metal cap around the first end of the circular ceramic tube to form an interference fit. The bottom of the first metal cap is provided with a through hole aligned with the opening of the first end of the circular ceramic tube;

[0066] 2) Lead and melt forming: The middle section of a round metal wire (e.g., tinned copper wire) is rolled or stamped into a flat shape, and then a melt with one or more narrow necks is laser cut or punched out, thereby forming an integrated structure with leads at both ends and a melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively.

[0067] 3) Melting point low melting point metal: Use a heating device, such as an electric soldering iron, to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck;

[0068] 4) Assembling the lead wire and melt into the ceramic tube: Insert the first lead wire through the second end opening of the circular ceramic tube, and then pass it through the first end opening of the circular ceramic tube and the through hole at the bottom of the first metal cap. The diameter of the first end opening of the circular ceramic tube is smaller than the width of the melt. The transition section between the melt and the first lead wire is clamped at the first end opening of the circular ceramic tube to achieve positioning;

[0069] 5) Filling the arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt;

[0070] 6) Assembling the second metal cap: A through hole is provided at the bottom of the second metal cap. The second lead is passed through the through hole at the bottom of the second metal cap. Then, the second metal cap is wrapped around the second end of the circular ceramic tube to form an interference fit with it.

[0071] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art will appreciate that various changes in form and detail may be made to the present invention without departing from the spirit and scope of the present invention as defined by the appended claims. For example, the solutions of Embodiments 1 and 2 may be combined on the same fuse, with a sealant being used at one end of the insulating shell and a metal cap being used at the other end. Such simple changes and combinations are within the scope of protection of the present invention.

Claims

1. A method for manufacturing a tubular current fuse with integrated lead and fuse, comprising the following steps: 1) Lead and melt forming: The middle section of the round metal wire is rolled or stamped into a flat shape, and then the melt with multiple narrow necks is laser cut or punched out, thereby forming an integrated structure with leads at both ends and melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively; 2) Melting point low melting point metal: Use a heating device to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck; 3) The lead wire melt assembly is assembled into the ceramic tube: the first lead wire is inserted from the opening of the second end of the circular ceramic tube, and then passed out from the opening of the first end of the circular ceramic tube, the melt is located in the inner hole of the circular ceramic tube, the opening diameter of the first end of the circular ceramic tube is smaller than the width of the melt, the transition section between the melt and the first lead wire is clamped at the opening of the first end of the circular ceramic tube to achieve positioning, and the second lead wire is exposed outside the opening of the second end of the circular ceramic tube; 4) Filling arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt; 5) Assembling the insulating positioning block: the ceramic positioning block has a center hole, the second lead wire is passed through the center hole of the ceramic positioning block, and then the ceramic positioning block is pressed into the opening of the second end of the circular ceramic tube; 6) Sealing: Seal the first end and the second end of the circular ceramic tube with sealant.

2. A method for manufacturing a tubular current fuse with integrated lead and fuse, comprising the following steps: 1) Assembling the first metal cap: aligning the mouth of the first metal cap with the first end of the circular ceramic tube, and wrapping the first end of the circular ceramic tube with the first metal cap by crimping to form an interference fit, and a through hole is provided at the bottom of the first metal cap that is aligned with the opening of the first end of the circular ceramic tube; 2) Lead and melt forming: The middle section of the round metal wire is rolled or stamped into a flat shape, and then the melt with multiple narrow necks is laser cut or punched out, thereby forming an integrated structure with leads at both ends and melt in the middle. The leads at both ends of the melt are the first lead and the second lead respectively; 3) Melting point low melting point metal: Use a heating device to weld an appropriate amount of low melting point metal to the melt surface next to the narrow neck; 4) The lead wire melt assembly is assembled into the ceramic tube: the first lead wire is inserted into the second end opening of the circular ceramic tube, and then passed out from the first end opening of the circular ceramic tube and the through hole at the bottom of the first metal cap. The opening diameter of the first end of the circular ceramic tube is smaller than the width of the melt. The transition section between the melt and the first lead wire is clamped at the first end opening of the circular ceramic tube to achieve positioning; 5) Filling arc extinguishing medium: Place the second end of the circular ceramic tube upwards, and fill an appropriate amount of quartz sand into the opening of the second end of the circular ceramic tube to wrap around the melt; 6) Assembling the second metal cap: a through hole is provided at the bottom of the second metal cap, and the second lead wire is passed through the through hole at the bottom of the second metal cap. Then, the second metal cap is wrapped around the second end of the circular ceramic tube to form an interference fit therewith.

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