A fuse

Abstract

A kind of fuse, including tube shell, fuse body, arc extinguishing medium;There is bimetallic strip in series on fuse body, at least one row of narrow neck is opened on the fuse body near one side or both sides of bimetallic strip;Fuse body with bimetallic strip in series is arranged in tube shell, one end of bimetallic strip in the width direction of fuse body is fixedly arranged on tube shell, and baffle is arranged on one side or both sides of bimetallic strip in the length direction of fuse body, and fuse body passes through baffle, the shape of baffle matches the shape of inner wall of tube shell, and arc extinguishing medium is filled in the cavity between baffle and the end of tube shell;Bimetallic strip is located outside arc extinguishing medium, and narrow neck is located in arc extinguishing medium.By introducing bimetallic strip, the fuse body melting time is shortened, the post-failure insulation resistance is increased, and the breaking capacity is improved.

Description

Technical Field

[0001] This invention relates to the field of circuit protection, specifically to fuses used for circuit protection. Background Technology

[0002] A fuse is used for circuit protection. A fuse generally consists of a casing filled with an arc-quenching medium. The fusible element passes through this medium within the casing, and a slit is provided on the fusible element for breaking the arc. The slit is located within the arc-quenching medium. When a fault current occurs in the circuit, the temperature at the slit first rises to the melting point of the fusible element, causing it to melt and break at the slit, forming a fracture. The resulting arc is extinguished by the arc-quenching medium. These fuses have a simple structure, are easy to manufacture, and have a high breaking capacity. For large short-circuit currents, the breaking time is very short, and the insulation resistance after breaking is high. However, for overloads or relatively small short-circuit currents, the breaking time is longer, fluctuates significantly, and is unstable, and the insulation resistance after breaking is lower. Summary of the Invention

[0003] The purpose of this invention is to provide a fuse in which a bimetallic strip is connected in series on the molten element. When the molten element melts, the bimetallic strip deforms in conjunction with the melting of the molten element, forming a rapid fracture on the molten element and widening the fracture surface, thereby increasing the distance between the fracture surfaces, shortening the breaking time, increasing the insulation resistance after the break, and improving the insulation performance after the break.

[0004] To achieve the above-mentioned objectives, the present invention provides a fuse, comprising a casing, a fusible element, and an arc-extinguishing medium; a bimetallic strip is connected in series on the fusible element, and at least one row of narrow necks is formed on one or both sides of the fusible element near the bimetallic strip; the fusible element with the bimetallic strip connected in series passes through the casing, one end of the bimetallic strip in the width direction of the fusible element is fixedly disposed on the casing, and a partition is provided on one or both sides of the bimetallic strip in the length direction of the fusible element, through which the fusible element passes, the shape of the partition matching the shape of the inner wall of the casing, and the cavity between the partition and the end of the casing is filled with the arc-extinguishing medium; the bimetallic strip is located outside the arc-extinguishing medium, and the narrow necks are located within the arc-extinguishing medium.

[0005] Preferably, in the width direction of the melt, one end of the bimetallic strip protrudes from the edge of the melt to form a stationary connection end, and the stationary connection end is fixedly connected to the inner wall of the tube shell.

[0006] Preferably, the stationary connection end has a convex structure.

[0007] Preferably, the melt includes a first melt and a second melt, and the bimetallic strip is located between the first melt and the second melt. The bimetallic strip is electrically connected to one end of the first melt and the second melt, respectively, so that the bimetallic strip is connected in series with the melt.

[0008] Preferably, the partition is connected and fixed to the inner wall of the tube shell by welding, gluing, or a connecting structure.

[0009] Preferably, the two ends of the tube shell are sealed by end caps, the conductive terminals are disposed on the end caps, and the two ends of the molten material are electrically connected to the end caps respectively.

[0010] Preferably, the end cap is integrally formed with the conductive terminal.

[0011] This invention introduces a bimetallic strip, which has a higher resistance than the molten metal. By connecting the molten metal and the bimetallic strip in series, on the one hand, Joule heating is increased to accelerate the melting of the molten metal, and on the other hand, the thermal deformation characteristics of the bimetallic strip are used to drive the movement of the molten metal, thereby expanding the insulation distance after the break at the narrow point to form a higher insulation resistance. For large short-circuit currents, it is also beneficial to increase the arc voltage and accelerate the extinction of the arc. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the external structure of a fuse.

[0013] Figure 2 This is a cross-sectional view of a fuse with double baffles.

[0014] Figure 3 This is a schematic diagram of the melt structure.

[0015] Figure 4 This is a cross-sectional view of a fuse with a single partition.

[0016] Figure 5 This is a schematic diagram of the melt structure.

[0017] Figure Labels

[0018] 1. Shell 2. End cap 3. Conductive terminal 4. Bimetallic strip 5. Divider 6. Arc extinguishing medium 7. First melt 8. Second melt 9. Neck 401. Stationary connection end. Detailed Implementation

[0019] The fuse of the present invention includes a shell, a fusible element, and an arc-extinguishing medium; a bimetallic strip is connected in series on the fusible element, and at least one row of narrow necks is formed on one or both sides of the fusible element near the bimetallic strip; the fusible element with the bimetallic strip connected in series passes through the shell, one end of the bimetallic strip in the width direction of the fusible element is fixedly disposed on the shell, and a partition is provided on one or both sides of the bimetallic strip in the length direction of the fusible element, through which the fusible element passes, the shape of the partition matches the shape of the inner wall of the shell, and the cavity between the partition and the end of the shell is filled with the arc-extinguishing medium; the bimetallic strip is located outside the arc-extinguishing medium, and the narrow necks are located in the arc-extinguishing medium.

[0020] The following describes preferred embodiments in detail with reference to the accompanying drawings. The directional terms used are for reference only and do not constitute a limitation on the technical solution of this invention.

[0021] Fuse, see Figure 1 and Figure 2 The system includes a shell 1, end caps 2, conductive terminals 3, a bimetallic strip 4, a partition 5, an arc-extinguishing medium 6, and a molten material. The shell 1 is made of insulating material and is a tubular structure extending through both ends. End caps 2 are fitted onto both ends of the shell 1, sealing the ends of the shell 1. The end caps 2 are fixed to the shell 1 by riveting or adhesive. Conductive terminals 3 are electrically connected to the end face of the end caps 2 away from the shell 1. The end caps 2 are made of conductive material and can be separate parts from the conductive terminals 3, or they can be an integrally formed structure; in this embodiment, they are an integrally formed structure.

[0022] Melt, see Figure 3 The system includes a first melt 7 and a second melt 8. A bimetallic strip 4 is located between the first melt 7 and the second melt 8 and is electrically connected to one end of each melt 7 and melt 8, forming a series connection structure between the melt and the bimetallic strip 4. The other ends of the first melt 7 and the second melt 8 are electrically connected to end caps 2. The first melt 7 and the second melt 8 are connected to the bimetallic strip 4, and the melt and the end cap are connected by welding. At least one row of narrow necks 9 are provided on the first melt 7 and the second melt 8 on both sides of the bimetallic strip 4. The narrow necks 9 are positioned close to the bimetallic strip 4 so that, in the event of a fault current, the heat energy on the bimetallic strip 4 is quickly transferred to the narrow necks, accelerating the melting of the narrow necks.

[0023] The bimetallic strip 4 deforms when heated. It extends through the width of the melt and its resistance is greater than that of the melt. Along the width of the melt, one end of the bimetallic strip 4 is a free end, while the other end protrudes from the edge of the melt to form a stationary connection end 401, which has a convex structure. The stationary connection end 401 of the bimetallic strip 4 is fixed to the inner wall of the casing 1 by adhesive.

[0024] Partitions 5 are provided on the outer sides of both ends of the bimetallic strip 4 along the length of the molten material, with a certain distance maintained between the bimetallic strip 4 and the partitions 5. The partitions 5 are made of insulating material, and the first molten material 7 and the second molten material 8 pass through the partitions 5 respectively. The shape of the partitions 5 matches the inner wall shape of the tube shell 1. The partitions 5 are fixed to the inner wall of the tube shell 1 by welding or gluing. Alternatively, a groove can be provided on the inner wall of the tube shell 1, and a buckle can be provided at the corresponding position on the outer periphery of the partitions 5. The partitions 5 on both sides of the bimetallic strip 4 divide the interior of the tube shell 1 into three cavities. The cavity between the partitions 5 and the end cap of the tube shell 1 is filled with an arc-extinguishing medium, and the necks on the first molten material 7 and the second molten material 8 on both sides of the bimetallic strip 4 are located in the arc-extinguishing medium. The cavity where the bimetallic strip 4 is located between the two partitions 5 is not filled with an arc-extinguishing medium, leaving space for the thermal deformation of the bimetallic strip 4.

[0025] Working principle:

[0026] When a fault current occurs, because the resistance of the bimetallic strip 4 is greater than that of the molten metal, the heat generated on the bimetallic strip 4 is rapidly transferred to the neck near the bimetallic strip 4, causing the temperature at the neck to rise rapidly to the melting point, accelerating melting and forming a fracture at the neck. At the same time, because the bimetallic strip 4 deforms and bends under the action of heat, the deformation of the bimetallic strip 4 creates a tensile force at the neck, further accelerating the melting and fracture of the neck. After melting, the fracture is further widened, making the final fracture distance at the upper end of the molten metal greater than the fracture distance of the molten metal without the bimetallic strip. This increases the post-fracture insulation resistance at the fracture point of the molten metal, shortens the melting time, and improves the breaking capacity.

[0027] exist Figures 2 to 3 Based on this, one partition can be removed, see [link / reference]. Figure 4 and Figure 5 A row of narrow necks 9 is provided only on the first molten material 7 near the bimetallic strip 4. Simultaneously, a partition 5 is provided on one side of the bimetallic strip 4 where the first molten material 7 is located, dividing the interior of the shell 1 into two cavities. The cavity between the partition 5 and the end of the shell 1 is filled with an arc-extinguishing medium, placing the narrow necks 9 of the first molten material 7 within the arc-extinguishing medium, while placing both the bimetallic strip 4 and the second molten material 8 outside the arc-extinguishing medium, thus providing space for the bimetallic strip 4 to deform. Its operating principle is the same as described above.

Claims

1. A fuse, characterized in that, The device includes a shell, a molten material, and an arc-extinguishing medium. A bimetallic strip is connected in series on the molten material, and at least one row of narrow necks is formed on one or both sides of the molten material near the bimetallic strip. The molten material with the bimetallic strip connected in series passes through the shell. One end of the bimetallic strip in the width direction of the molten material is fixedly disposed on the shell. A partition is provided on one or both sides of the bimetallic strip in the length direction of the molten material, through which the molten material passes. The shape of the partition matches the shape of the inner wall of the shell. The cavity between the partition and the end of the shell is filled with the arc-extinguishing medium. The bimetallic strip is located outside the arc-extinguishing medium, and the narrow necks are located within the arc-extinguishing medium.

2. The fuse according to claim 1, characterized in that, In the width direction of the melt, one end of the bimetallic strip protrudes from the edge of the melt to form a stationary connection end, which is fixedly connected to the inner wall of the tube shell.

3. The fuse according to claim 2, characterized in that, The stationary connection end has a convex structure.

4. The fuse according to claim 1, characterized in that, The melt includes a first melt and a second melt, and the bimetallic strip is located between the first melt and the second melt. The bimetallic strip is electrically connected to one end of the first melt and the second melt, respectively, so that the bimetallic strip and the melt are connected in series.

5. The fuse according to claim 1, characterized in that, The partition is connected and fixed to the inner wall of the tube shell by welding, gluing or connecting structure.

6. The fuse according to claim 1, characterized in that, The two ends of the tube shell are sealed by end caps, the conductive terminals are disposed on the end caps, and the two ends of the molten material are electrically connected to the end caps respectively.

7. The fuse according to claim 6, characterized in that, The end cap is integrally formed with the conductive terminal.

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