A surface mount fuse

Abstract

The present invention discloses a surface mounted fuse, comprising a shell and a fuse body; the shell comprises a base and an upper cover, the base has a cavity, end walls at both ends of the cavity, and hollow parts at both sides of the cavity; the hollow parts are connected to the gap between the periphery of the base and the upper wall of the upper cover, thereby finally connecting the cavity with the outside. When the fuse is blown, the gas pressure generated inside the cavity is rapidly reduced by the pressure relief effect of the hollow parts and the gap, so as to improve the breaking capacity.

Description

Technical Field

[0001] The invention relates to a fuse, in particular to a large-rated current fuse with high breaking capacity. Background Art

[0002] With the development of industries such as power batteries and small energy storage tools, the demand for high-current surface-mount fuse products is increasing. As the power of equipment gradually increases, the rated voltage and possible fault current of the circuit are gradually increasing. As a result, the requirements for the rated breaking capacity of fuse products are getting higher and higher.

[0003] The impact of the fuse breaking process can generally be divided into two parts: the pulse pressure generated at the moment when the fuse is just vaporized and arcing - the explosion pressure and the pressure generated during the entire arcing period - the arcing pressure. At the moment when the fuse is vaporized and arcing, a pulse explosion pressure with a fast rise and short duration will be generated; the arcing pressure exists in the entire arcing process, and its pressure change is completely controlled by the current change during the arcing process. If the current after arcing is reduced, the arcing pressure will not rise significantly, and the damage to the tube shell is very small. However, if the current remains unchanged or continues to rise, the arcing pressure will inevitably rise, and the arcing pressure will also cause greater damage to the tube shell. As the arcing time increases, the temperature of the tube shell increases, the strength decreases, and finally causes the tube shell to rupture or explode. Therefore, the key to quickly extinguishing the arc and improving the breaking capacity of the fuse product is to reduce the gas pressure in the shell. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the present invention provides a surface mounted fuse to solve the technical problem of how to quickly release pressure when the fuse is blown.

[0005] To achieve the above purpose, a technical solution that can be adopted by the present invention is:

[0006] A surface mounted fuse comprises a shell and a fuse body; the shell comprises a base and an upper cover, the base comprises a cavity, end walls located at both ends of the cavity, and hollow parts located at both sides of the cavity; the upper cover comprises a cover body covering the base and an upper wall surface extending downward from the periphery of the cover body and surrounding the base; the fuse body comprises a fuse body located in the cavity, bent parts bent from both ends of the fuse body and respectively resting on two hollow parts, and end electrodes formed from the outer ends of the bent parts; a gap is provided between the periphery of the base and the upper wall surface of the upper cover, and the hollow part is connected to the gap.

[0007] The beneficial effect of the present invention is that the two sides of the base are opened up to form hollow parts, and the hollow parts are connected to the gap between the periphery of the base and the upper wall of the upper cover, so that the cavity is finally connected to the outside. When melting occurs, the gas pressure generated inside the cavity is rapidly reduced by the pressure relief effect of the hollow parts and the gap, so as to improve the breaking capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a longitudinal cross-sectional view of the fuse according to the first embodiment of the present invention;

[0009] Figure 2 is a three-dimensional diagram of the base in the first embodiment of the present invention;

[0010] Figure 3 is a three-dimensional diagram of the base in the second embodiment of the present invention;

[0011] Figure 4 is a three-dimensional diagram of the base in the third embodiment of the present invention;

[0012] Figure 5 It is a three-dimensional diagram of the cooperation between the fuse link and the base in the third embodiment of the present invention;

[0013] Figure 6 is a side view of the base in the fourth embodiment of the present invention;

[0014] Figure 7 It is a schematic diagram of the structure of the base and the upper cover in the fourth embodiment of the present invention;

[0015] Figure 8 It is a schematic diagram of the structure of the fuse, the base and the upper cover in the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to fully and clearly describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0017] Embodiment 1

[0018] like Figure 1 and Figure 2As shown, this embodiment discloses a surface-mount fuse, including a shell and a fuse body 1. The shell includes a base 2 and an upper cover 3. The base 2 has a cavity 21, end walls 22 located at both ends of the cavity 21, and hollow parts 23 located on both sides of the cavity 21. The bottom surface of the cavity 21 is a plane. In this embodiment, two opposite positioning columns 24 are respectively provided on both sides of the cavity of the base 2, and one positioning column 24 is vertically connected to the end wall 22 at one end. The hollow part 23 is between the two positioning columns 24. The upper cover 3 is a shell with a square appearance, and its material is ceramic or high-temperature resistant plastic. The material of the base 2 is also ceramic or high-temperature resistant plastic.

[0019] The upper cover 3 has a cover body 31 covering the base 2 and an upper wall surface 32 extending downward from the periphery of the cover body 31 and surrounding the base. The fuse 1 includes a fuse body 11 located in the cavity 21, an inverted U-shaped bent portion 12 bent from both ends of the fuse body 11 and respectively resting on two positioning pillars 24, and an end electrode 13 formed from the outer end of the inverted U-shaped bent portion 12. There is a gap between the periphery of the base 2 and the upper wall surface 32 of the upper cover 3, and the gap extends from top to bottom and communicates with the outside at the bottom of the fuse. The hollow part 23 is connected to the gap. The positioning pillar 24 and the end wall 22 are used to work together to limit the fuse 1, specifically in that the part of the inverted U-shaped bent portion 12 located in the cavity 21 is stuck in the space surrounded by the end wall 22 and the inner side of the positioning pillar 24. The cavity 21 includes a filling material 4 that wraps the fuse body 11. The filling material is at least one of powder materials such as quartz sand, aluminum hydroxide, and gas-generating materials. The fuse 1 is made of copper, silver or alloy material, and the surface of the fuse is plated with silver or tin.

[0020] An adhesive 5 is provided between the cover 31 and the inverted U-shaped bent portion 12, and between the upper wall of the cover and the base end wall 22. The adhesive 5 is a high temperature resistant resin material, and is used to bond the base 2 and the upper cover 3 to form a whole.

[0021] When the fuse is in use, if the current is overloaded and the fuse element 1 is blown, the gas pressure generated in the cavity is rapidly reduced by the pressure relief effect of the hollow part and the gap, so as to improve the breaking capacity.

[0022] Embodiment 2

[0023] Please combine Figure 3As shown, this embodiment discloses another surface mounted fuse, including a base, an upper cover and a fuse. The structure of the fuse and the upper cover is the same as that of the fuse 1 and the upper cover 3 in the first embodiment. The difference between the second embodiment and the first embodiment is that the structure of the position of the hollow part of the base 2 in the second embodiment is different from that in the first embodiment. In this embodiment, side walls 25 are respectively provided on both sides of the cavity of the base 2, and the hollow part 23 is formed by hollowing out the side walls 25; and a cross beam 27 is provided above the hollow part 23, and the height of the cross beam 27 is consistent with the height of the end wall 22. The function of the cross beam 27 is to fix the position of the fuse, that is, when the fuse is installed, the inverted U-shaped bend of the fuse is stuck on the cross beam 27. In addition, during the manufacturing process of the base, the two end walls 22 can remain upright and not deformed.

[0024] Embodiment 3

[0025] Please combine Figure 4 As shown, this embodiment discloses another surface-mount fuse, including a base, an upper cover and a fuse. The structure of the fuse and the upper cover is the same as the structure of the fuse 1 and the upper cover 3 in the first embodiment. The difference between the third embodiment and the first embodiment is that the structure of the base 2 in the third embodiment is different from that in the first embodiment. In this embodiment, the bottom surface of the cavity 21 in the base is an arc-shaped bottom surface with a low middle and high sides; the two sides of the arc-shaped bottom surface form a hollow part 23 with the bottom surface also being an arc. The design of the arc-shaped bottom surface makes the end walls 22 at both ends present a structure with a thick lower part and a thin upper part, so that the end walls 22 can remain unchanged during the manufacturing and use process and enhance the overall structure. Compared with the bases of the first and third embodiments, the design of the arc-shaped bottom surface is less difficult to manufacture and has a stronger structure.

[0026] Please combine again Figure 5 As shown, the portion 28 of the inverted U-shaped bent portion of the fuse 1 located in the cavity is narrower than the portion 29 resting on the two end walls 22. Therefore, the fuse 1 is located on the base 2, and the portion 29 resting on the two end walls 22 is used to locate the position of the fuse 1, while the portion 28 in the cavity does not interfere with the two end walls 22 and extends into the cavity.

[0027] Embodiment 4

[0028] Please combine Figures 6 to 8 As shown, this embodiment discloses another surface mounted fuse, including a base 2 , an upper cover 3 and a fuse body 1 .

[0029] The bottom surface of the cavity 21 in the base is an arc-shaped bottom surface which is low in the middle and high at both sides; and the outer surfaces of the end walls 22 at both ends of the cavity 21 are arc-shaped side surfaces 221 which are gradually curved outward from top to bottom.

[0030] Please combine again Figure 5As shown, the fuse 1 has the same structure as the fuse in the third embodiment, and the portion 28 of the inverted U-shaped bend located in the cavity is narrower than the portion 29 resting on the two end walls 22 .

[0031] In this embodiment, the base 2 is made of ceramic material, and the outer surface of the end wall 22 is made into an arc shape so that the middle end wall 22 can stand upright, and the forces on both sides are balanced to prevent the ceramic from collapsing during sintering. At the same time, the arc-shaped end wall 22 forms a larger space between the end wall 22 and the upper cover 3 to accommodate more adhesive to enhance the bonding strength.

Claims

1. A surface mount fuse, comprising a housing and a fuse body; characterized in that: The housing comprises a base and an upper cover, wherein the base comprises a cavity, end walls at both ends of the cavity, and hollow parts at both sides of the cavity; the upper cover comprises a cover body covering the base and an upper wall surface extending downward from the periphery of the cover body and surrounding the base; the fuse comprises a fuse body located in the cavity, bent parts bent from both ends of the fuse body and respectively resting on the two hollow parts, and end electrodes formed from the outer ends of the bent parts; a gap is provided between the periphery of the base and the upper wall surface of the upper cover, and the hollow part is connected to the gap; The bottom surface of the cavity is an arc-shaped bottom surface which is low in the middle and high on both sides; the two sides of the arc-shaped bottom surface form a hollow part whose bottom surface is also arc-shaped; the outer surfaces of the end walls at both ends of the cavity are arc-shaped side surfaces which are gradually bent outward from top to bottom.

2. The surface mount fuse according to claim 1, characterized in that: Adhesive is provided between the cover body and the bent portion, and between the upper wall surface of the cover body and the end wall of the base.

3. The surface mount fuse according to claim 2, characterized in that: The cavity includes a filling material that wraps the fuse body; the filling material is at least one of quartz sand, aluminum hydroxide, and a gas-generating material.

4. The surface mount fuse according to claim 2, characterized in that: The upper cover is a shell with a square appearance, and its material is ceramic or high temperature resistant plastic; the fuse is made of copper, silver or alloy material, and the surface of the fuse is plated with silver or tin.

5. The surface mount fuse according to claim 1, characterized in that: A crossbeam is arranged above the hollow part, and the height of the crossbeam is consistent with the height of the end wall.

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