A winding type melt fuse

Abstract

The application relates to a winding type melt fuse, which comprises a shell, a melt arranged in the shell, and contact blades arranged outside the shell and connected with both ends of the melt respectively, wherein a single-layer non-enclosed cylindrical coiled elastic sheet is arranged in the shell, the melt is wound on the outer periphery of the elastic sheet, and a melting weak part of the melt is arranged at an opening on the cylindrical outer periphery of the elastic sheet. The melt fuse can shorten the melt breaking time, improve the breaking capacity and arc extinguishing capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric power control and circuit protection in electric vehicles, in particular to a fuse structure for electric power, electric vehicles and the like. BACKGROUND

[0002] At present, thermal fuse is commonly used as a protection device for electric circuit of electric vehicle battery pack, and the structure of thermal fuse includes a contact blade, a gland, a fuse body, arc extinguishing medium and a porcelain tube. The working principle is as follows: when the current in the circuit exceeds the specified value, i.e. when the fault current occurs, the circuit current passes through the fuse body via the contact blade, and the current heat accumulation effect is utilized to make the current sensing point of the fuse body, i.e. the narrow neck, melt and break off and extinguish the arc within a certain time, thereby safely breaking the fault current. Although the structure of the fuse has good performance, it still has certain deficiencies: in the case of a small current fuse, the fuse breaking speed is slow, and breaking failure is likely to occur; in the case of a small current fuse, the breaking capacity is low; and the fuse body is prone to sticking to the inner wall of the porcelain tube during the fuse breaking process, which causes the porcelain tube to burst due to temperature difference. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a fuse capable of accelerating the fuse body breaking speed, so as to accelerate the fuse body breaking, enlarge the breaking gap, and improve the breaking capacity and arc extinguishing capacity.

[0004] To solve the above technical problem, the technical solution provided by the present application is a fuse with a winding type fuse body, which comprises a shell, a fuse body arranged in the shell, and a contact blade connected to both ends of the fuse body outside the shell, characterized in that a single-layer non-closed cylindrical elastic sheet is arranged in the shell, the fuse body is wound on the outer periphery of the elastic sheet, and the fuse breaking weak point of the fuse body is located at the opening on the cylindrical outer periphery of the elastic sheet.

[0005] At least one end edge of the opening on the cylindrical outer periphery of the elastic sheet is divided into a plurality of small elastic sheets, and the fuse body on one side of the fuse breaking weak point is wound on the small elastic sheets; when the fuse breaking weak point softens, the small elastic sheets can break the fuse breaking weak point.

[0006] The fuse body has a wire or strip structure.

[0007] The fuse breaking weak point is a narrow diameter or a metallurgical effect provided on the fuse body.

[0008] The fuse body is fixed on the outer periphery of the elastic sheet by glue.

[0009] Limiting holes or limiting grooves are formed in the elastic sheet for winding the fuse body.

[0010] The limiting grooves have the same winding path as the fuse body on the elastic sheet.

[0011] At least three limiting holes are arranged on each winding path between the two end edges of the elastic sheet.

[0012] The elastic sheet is made of insulating material, preferably high molecular material, which can release gas when burned at high temperature, form local high pressure at the fracture, and improve arc extinguishing capacity. When the fuse is broken, the small elastic sheet and the overall elasticity of the elastic sheet can quickly break the weak part of the fuse. The limiting holes or limiting grooves arranged on the elastic sheet can prevent the fuse from sliding on the elastic sheet. In addition, the limiting holes and limiting grooves have a diameter or groove width slightly smaller than the outer diameter of the fuse, which can be clamped in the limiting holes or limiting grooves through interference winding during winding, thereby improving the limiting and fixing effect.

[0013] The fuse of the present application applies elastic force to the weak part of the fuse through the crimped elastic sheet arranged in the shell. When the fault current is generated and the weak part of the fuse is softened due to temperature rise, the weak part of the fuse is disconnected at the first time under the action of the small elastic sheet before the fuse is broken, and the gap distance is instantaneously enlarged by the small elastic sheet, thereby shortening the fuse breaking time, improving the breaking capacity and arc extinguishing capacity. When the fuse is broken, arc is generated at the weak part of the fuse, the elastic sheet is heated to generate gas, local high pressure is formed, and arc extinguishing capacity is improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The present application is a schematic diagram of the cross-sectional structure of the fuse.

[0015] Figure 2 The present application is a schematic diagram of the three-dimensional structure of the fuse after removing the porcelain tube and the cover plate.

[0016] Figure 3 The present application is another schematic diagram of the three-dimensional structure of the fuse after removing the porcelain tube and the cover plate.

[0017] Figure 4 The structure schematic diagram of the limiting hole arranged on the elastic sheet and the fuse winding path. DETAILED DESCRIPTION

[0018] For the above technical solution, a preferred embodiment is first described in detail in combination with the drawings, referring to Figure 1 and Figure 3 Wherein:

[0019] The fuse of the present application, referring to Figure 1 , includes a hollow porcelain tube 101, a fuse 103 arranged in the porcelain tube 101, and a contact knife 104 fixedly connected to one end of the porcelain tube. One end of the contact knife 104 penetrates through the cover plate 106 and is located outside the porcelain tube. The porcelain tube is filled with arc extinguishing medium 102, and the arc extinguishing medium 102 is a gas or liquid arc extinguishing medium.

[0020] The melt 103 has a strip-like or filament-like structure. Several weak points A are spaced apart on the melt. These weak points can be narrow sections or metallurgical effect areas on the melt; in this embodiment, the illustration shows metallurgical effect areas. A narrow section is the part with the smallest cross-section in the melt, where the resistance is highest. When a fault current occurs, the temperature rises fastest at the narrow section, resulting in the earliest melting. A metallurgical effect area is formed by coating the melt with a layer of low-melting-point metal. When a fault current occurs, the low-melting-point metal melts first, accelerating the softening and melting of the melt body.

[0021] The elastic sheet 105 is a square sheet structure that, when rolled up, forms a C-shape, i.e., a non-closed cylindrical structure. A gap remains between the two sides of the rolled-up cylindrical elastic sheet; this gap forms the opening 108 on the outer circumferential surface of the elastic sheet. The opening of the elastic sheet is divided into several small elastic pieces 107 on one or both sides. The molten material 103 is wound around the outer circumferential surface of the rolled-up elastic sheet, ensuring that the weakest point of the melt is located at the opening on the outer circumferential surface of the cylindrical elastic sheet, and that the melt portion on one side of the weakest point is precisely located on the outer circumferential surface of the small elastic piece. Because the rolled-up cylindrical elastic sheet has an opening elasticity, the melt wound around the elastic sheet can be well tensioned on the outer circumferential surface of the rolled-up elastic sheet. To further fix the melt, adhesive can be applied to the outer circumferential surface of the rolled-up elastic sheet to fix the melt to the outer circumferential surface.

[0022] To prevent the melt from slipping while wound around the coiled elastic sheet, a limiting groove with the same trajectory as the melt winding path can be formed on the elastic sheet, and a limiting groove can be provided on each small elastic sheet. The melt 103 is wound in the limiting groove on the outer circumference of the coiled elastic sheet to prevent the melt from slipping on the elastic sheet. Alternatively, at least three limiting holes 110 can be formed at intervals on each melt winding path between the two end edges of the elastic sheet, see [reference]. Figure 4 When the elastic sheet is curled, the limiting holes become slot-like structures. During molten metal winding, the metal is engaged at these limiting holes, thus positioning the melt and preventing it from sliding on the curled elastic sheet. The limiting holes or slots on the elastic sheet prevent the melt from sliding. Furthermore, the diameter or width of the limiting holes or slots can be slightly smaller than the outer diameter of the melt. During winding, interference winding can be used to secure the melt within the limiting holes or slots, enhancing the limiting and fixing effect.

[0023] Regardless of the method of winding the melt, it is essential to ensure that the weak point of the melt is located at the opening on the non-closed cylindrical outer circumference of the elastic sheet, and that the melt portion on one side of the weak point is located exactly on the outer circumference of the small elastic sheet.

[0024] In the assembly, the melt is firstly wound on the curled non-closed cylindrical elastic sheet, and the weak part of the melt is located at the opening of the elastic sheet; then the elastic sheet wound with the melt is located between the two contact knives, and the two ends of the melt are welded on the two ends of the contact knife respectively for fixation, and the contact knife and the melt are assembled with the porcelain tube.

[0025] When the fault current is generated, the weak part of the melt is softened due to the temperature rise, and the weak part of the melt is quickly disconnected under the elastic force of the small elastic sheet and the elastic sheet as a whole, so that the disconnecting time is shortened, the distance of the disconnected part is enlarged, and the arc is quickly extinguished; at the same time, since the elastic support is made of a high polymer material, gas is generated when the elastic support is burned by the arc, the pressure of the disconnected part is increased, the arc is quickly extinguished in the arc extinguishing medium, and the fault current is cut off. When the small elastic sheet is formed at the opening of the uncut elastic sheet, the elastic force of the elastic sheet for pulling the weak part of the melt is small when the melt is fused, but after the disconnected part is disconnected, the elastic force of the elastic sheet can quickly pull the disconnected part apart to increase the breaking capacity and the arc extinguishing capacity. Therefore, the fuse of the present application shortens the disconnecting time and improves the breaking capacity and the arc extinguishing capacity.

Claims

1. A winding type fuse comprising a housing, a fuse element disposed in the housing, and contact blades disposed outside the housing and connected to both ends of the fuse element, characterized in that The elastic sheet is arranged in the shell in a single-layer non-closed cylindrical curling structure, and an opening is formed on the cylindrical outer circumferential surface of the elastic sheet; the melt is wound on the outer circumferential surface of the elastic sheet, and the melting thin weak part on the melt is located at the opening on the cylindrical outer circumferential surface of the elastic sheet.

2. The wrapped melt fuse of claim 1, wherein At least one end edge of the opening on the cylindrical outer circumferential surface of the elastic sheet is divided into a plurality of small elastic sheets, and the melt on the side of the melting thin weak part is wound on the small elastic sheets; when the melting thin weak part softens, the small elastic sheets can break the melting thin weak part.

3. The wrapped melt fuse of claim 1, wherein The melt is in a filament or strip structure.

4. The wrapped melt fuse of claim 1, wherein The melting thin weak part is a narrow diameter or a metallurgical effect provided on the melt.

5. The wrapped melt fuse of claim 1, wherein The melt is fixed on the outer circumferential surface of the elastic sheet by glue.

6. The wrapped melt fuse of claim 1, wherein Limiting holes or limiting grooves are arranged on the elastic sheet to prevent the melt from sliding after winding.

7. The wraparound melt fuse of claim 6, wherein The limiting grooves have the same winding path on the elastic sheet as the melt.

8. The wraparound melt fuse of claim 6, wherein At least three limiting holes are arranged on each winding path between the two end edges of the elastic sheet.

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