A small excitation fuse

Abstract

A small excitation fuse includes a shell, and an excitation device, a piston and a conductive plate arranged in sequence in the shell cavity, characterized in that the shell is integrally formed by injection molding, the cavity runs through the upper and lower ends of the shell, and an opening is opened on the side of the shell; the excitation device is installed at the upper end of the cavity to close the upper end opening of the cavity; a push-pull cover plate is arranged at the side opening of the shell, and the cover plate closes the lower end opening of the shell cavity and the side opening of the shell; and a disconnection weak point is opened on the conductive plate. The present invention has a small size, light weight, small internal resistance, simple assembly and short working time.

Description

Technical Field

[0001] The present invention relates to the fields of power control and electric vehicles, and particularly to a small excitation fuse. Background Art

[0002] Currently, thermal fuses are commonly used as circuit protection devices in electric vehicle battery packs. The structure of a thermal fuse includes a contact blade, a gland, a fuse element, an arc extinguishing medium, a tube shell, a pressure cap, etc. The working principle is as follows: When the current in the circuit exceeds the specified value, that is, when a fault current appears, the circuit current passes through the fuse element via the contact blade. By utilizing the current heat accumulation effect, the current sensing point (narrow neck) set on the fuse element melts and breaks within a certain time and extinguishes the arc, thereby safely interrupting the fault current.

[0003] The main problems and deficiencies are as follows: The tube shell of the fuse usually uses a porcelain tube, which is relatively heavy as a whole. And in the case of a large current, the volume of the fuse is also relatively large, unable to meet the application environment with high requirements for weight and volume; the internal resistance is relatively large, and the ineffective thermal power loss is high during normal operation, with a large amount of heat and high temperature; generally, the fuse can only operate when the current reaches more than 3 times the rated current, and the heat generation of the fuse element is slow at lower multiples of the current, resulting in a long time before it can be fused, and the fusing time is long, unable to achieve rapid protection; due to the very narrow and small cross-sectional area at the narrow diameter of the fuse element of the fuse, it cannot withstand long-term and multiple large current impacts, and is easily fused by the impact current, with poor current impact resistance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an excitation fuse with a small volume, convenient assembly, and light weight.

[0005] To solve the above technical problem, the technical solution provided by the present invention is a small excitation fuse, which includes a housing, and an excitation device, a piston, and a conductive plate are sequentially installed in the housing. It is characterized in that the housing is integrally formed by injection molding, cavities are opened through the upper and lower ends of the housing, and an opening is provided on the side surface of the housing; the excitation device is installed at the upper end of the cavity to close the upper opening of the cavity; a push-pullable cover plate is provided at the opening on the side surface of the housing, and the cover plate closes the lower opening of the housing cavity and the opening on the side surface of the housing; a break-weakened portion is provided on the conductive plate.

[0006] Long slots for installing the conductive plate from the side opening are provided on the two side walls of the opening on the side surface of the housing, and clamping grooves are provided on the inner side of the housing opposite to the opening on the side surface of the housing; a clamping protrusion that can be clamped into the clamping groove is provided at the position of the conductive plate corresponding to the clamping groove; short convex ribs that can be clamped into the long slots to fix the conductive plate are respectively provided at the positions on the cover plate corresponding to the long slots.

[0007] The cavity part of the housing above the conductive plate is separated from the opening on the side surface of the housing by a cavity wall.

[0008] At least one layer of clamping grids is provided on the outer side of the cavity wall at the side opening of the housing, and clamping bumps that can be clamped into the clamping grids are respectively provided at the corresponding positions on the cover plate.

[0009] A screw hole seat is provided on the cavity wall at one side of the side opening of the housing, and a through hole for a screw to pass through is provided at the corresponding position on the cover plate.

[0010] A support portion that supports the conductive plate is integrally formed on the side surface of the cover plate below the conductive plate, and a groove for the displacement of the piston at the break opening of the conductive plate and the broken part of the conductive plate is provided on the support portion.

[0011] The weak break point of the conductive plate is located on one side of the opening of the groove on the support portion of the cover plate; when the conductive plate breaks, the piston displaces downward along one side of the groove of the support portion of the cover plate in an interference fit manner, and at the same time pushes the broken part of the conductive plate to displace to the other side of the groove of the support portion of the cover plate.

[0012] A ventilation hole is provided at the bottom of the groove.

[0013] Convex ribs are provided at the bottom of the groove.

[0014] Clamping ridges are respectively provided on the two outer side surfaces of the support portion of the cover plate, and long guide grooves for the clamping of the clamping ridges are provided on the inner walls on both sides of the side opening of the housing.

[0015] Limit bumps are provided at intervals at the upper opening of the inner cavity of the housing, and corresponding limit grooves are provided on the excitation device; an installation groove for the penetration of a partition plate that supports the excitation device is provided in the cavity below the excitation device.

[0016] Limit grooves are provided at intervals on the inner wall of the housing cavity above the conductive plate, and corresponding compressible retractable limit clamping protrusions are provided at the positions corresponding to the limit grooves on the outer peripheral surface of the piston. When the piston is installed in the housing cavity, the limit clamping protrusions are clamped in the limit grooves; when the piston is driven by the excitation device, the piston can displace against the limitation of the limit clamping protrusions.

[0017] The piston includes an impact end, and the impact end is provided corresponding to the weak break point of the conductive plate.

[0018] A groove is provided on the end surface of the end of the piston in contact with the excitation device, and the gas release end of the excitation device is located in the groove.

[0019] The excitation device includes an ignition tube and a connecting tube connected together; the connecting tube is located at the upper opening of the housing, and the ignition tube is located in the cavity between the connecting tube and the piston; the upper end of the ignition tube is limited by the cavity shrinkage opening, and its lower end is supported and positioned by a partition or a piston inserted into the installation groove in the housing cavity.

[0020] An exhaust hole is provided at the contact surface between the piston and the housing cavity. When the piston is in the initial position, the piston covers the exhaust hole. When the piston displaces and disconnects the conductive plate, the piston leaves the exhaust hole.

[0021] For the excitation fuse of the present invention, since both the housing and the cover plate are integrally injection-molded, it is convenient for processing and has a light weight. Secondly, since the positioning structures between various device components have been designed on the housing and the cover plate, only the components need to be directly assembled in the order of assembly. The assembly is simple and convenient, and the assembly cycle is short, saving a large amount of production costs. Brief Description of the Drawings

[0022] Figure 1 , a schematic diagram of the structural decomposition of the present invention.

[0023] Figure 2 , a schematic diagram of the three-dimensional appearance structure.

[0024] Figure 3 , a schematic diagram of the side-sectional structure of the present invention.

[0025] Figure 4 , and Figure 3 Schematic diagrams of the side-sectional structure of the present invention in different directions.

[0026] Figure 5 , a schematic diagram of the structure in which the excitation device is composed of an ignition tube and a connecting tube. Detailed Description of the Invention

[0027] For the above technical solutions, preferred embodiments are now given for detailed description.

[0028] Housing 1, see Figures 1 to 4, it is injection-molded, with an opening on the side, openings are respectively provided at the upper and lower ends of the housing, and a through cavity is formed between the upper opening and the lower opening of the housing. Long slots 101 for the conductive plate 2 to pass through are provided on the side walls on both sides of the opening on the side of the housing 1. A support platform 102 for supporting the conductive plate is injection-molded on the inner side wall below the long slot of the housing. A long guide slot 103 for the cover plate 7 to pass through is injection-molded on the inner side wall below the support platform 102. A cavity wall is provided on one side of the opening on the side of the housing for the cavity above the support platform 102, which is separated from the opening on the side of the housing. Multiple layers of multiple clamping grids 104 are provided on the cavity wall on one side of the opening on the side of the housing. A screw hole seat 105 for the screw to pass through is injection-molded on the top of the cavity wall inside the opening on the side of the housing. A limiting groove 106 for limiting the piston 4 is provided on the cavity wall above the long slot 101, and a limiting step is also provided in the cavity above the limiting groove 106. An installation groove for the partition plate 5 to pass through is also provided on the inner wall of the cavity, and the partition plate 5 can be installed in the installation groove to limit the position of the excitation device 6. A limiting convex block 107 for limiting the excitation device is provided at the upper opening of the housing.

[0029] The cover plate 7 has an L-shaped drawer structure and is injection-molded. A support portion 701 for supporting the conductive plate extends from the lower end of the cover plate. A groove 708 is provided on the support portion 701, and convex ribs and multiple ventilation holes 710 are provided at the bottom of the groove. When the cover plate is installed, the groove forms a cavity, providing a displacement space for the disconnected part of the conductive plate and the displacement of the piston after the conductive plate is disconnected; through the ribs and ventilation holes provided at the bottom of the groove, it helps to extinguish the arc; the convex ribs can increase the arc ignition path at the break of the conductive plate, and the air heated by the arc generates pressure and is discharged outward through multiple ventilation holes, while blowing the arc to make it elongated into multiple small arcs, enhancing the cooling effect.

[0030] On the outer side surfaces on both sides of the support portion, clamping convex ribs 702 corresponding to the long guide slot 103 of the housing are respectively provided. A limiting convex rib 703 is provided on the side surface of the support portion 701 opposite to the cover plate. Corresponding limiting grooves are provided at the positions opposite to the limiting convex ribs on the side surface of the housing opposite to the cover plate. A through hole penetrating the support portion is provided on the support portion 701. Short convex ribs 704 corresponding to the long slot 101 are also provided on both sides of the cover plate. Clamping convex blocks (705, 706) corresponding to the clamping grids are also provided on the cover plate above the short convex ribs 704. A through hole 707 for the screw 709 to pass through is provided at the position on the cover plate corresponding to the screw hole seat above the clamping convex blocks.

[0031] A barb structure is provided on the cover support portion, and a groove or through hole is provided at the bottom of the shell corresponding to the barb position. When the cover is installed on the shell, the barb structure on the bottom of the cover can be stuck in the groove or through hole to limit the bottom of the cover. The upper part of the cover is fixed by screws, and the bottom of the cover is fixed by the barb structure to achieve the fixing of the cover on the shell.

[0032] The piston 4 includes a cylindrical portion 401 and an impact end 402 disposed below the cylindrical portion 401. The cylindrical portion 401 and the shell cavity are in sealed contact, interference fit, or a gap size that satisfies the high-pressure gas released by the excitation device to drive the piston to displace and interrupt the conductive plate, and the piston is disposed in the shell cavity. Guide ribs (403, 404) are disposed on opposite sides of the cylindrical portion and the impact end, and the guide ribs 403 and the guide ribs 404 are asymmetrically designed to prevent errors in the installation of the piston. A guide groove corresponding to the guide rib is disposed on the inner wall of the shell cavity. When the piston is installed in the cavity, the guide rib is located in the guide groove; when the piston is displaced, the piston can be displaced along the guide groove. On the cylindrical part 401, a limiting clamping protrusion 405 is provided corresponding to the limiting groove 106 of the shell. One end of the limiting clamping protrusion 405 is fixed on the cylindrical part, and a gap is reserved between the end protruding outward and the cylindrical part. When the limiting clamping protrusion 405 is squeezed by external force, the clamping protrusion can move into the gap and be flush with the cylindrical outer peripheral surface. When the squeezing force is removed, the limiting clamping protrusion 405 can return to the initial position. When the piston is installed in the shell cavity, the limiting clamping protrusion can be clamped in the limiting groove. When the piston is driven by the excitation device, the piston overcomes the limit of the limiting clamping protrusion and interrupts the conductive plate. A groove 406 is provided on the upper surface of the cylindrical part. When the excitation device is located above the interruption device, the gas release end of the excitation device is located in the groove 406. An exhaust hole communicating with the outside is opened on the cavity wall of the shell where the cylindrical part of the piston is located. When the piston is displaced by external force and breaks the conductive plate, the piston leaves the exhaust hole, exposing the exhaust hole to the cavity, and the gunpowder gas generated by the excitation device is discharged through the exhaust hole; when the piston is in the initial position, the piston covers the exhaust hole.

[0033] The excitation device 6, in this embodiment, is a gas generator, which can receive an external excitation signal, and according to the received excitation signal, ignite a chemical reaction to release high-pressure gas. A limiting groove 601 is provided on the outer side of the upper end of the gas generator, and the limiting groove 601 corresponds to the limiting protrusion 107 at the upper end opening of the shell cavity. When the excitation device is installed at the upper end position of the shell cavity, the limiting protrusion 107 can be stuck in the limiting groove 601 to prevent it from falling out of the upper end opening of the shell. The excitation device is positioned by the partition and the limiting protrusion 107. The lower end of the excitation device can also be limited and fixed by the upper end of the piston.

[0034] The conductive plate 2 is of a certain type structure in this embodiment. A clamping projection 201 is provided on one side of the conductive plate, and a corresponding clamping groove is formed in the side wall of the housing corresponding to the clamping projection. A breakage-weakening portion 202 is formed on the conductive plate. The breakage-weakening portion can be set as a notch, such as a U-shaped, V-shaped or semi-circular notch, or a reduced cross-section structure, or other structures or materials that can reduce the breakage strength of the conductive plate. The breakage-weakening portion of the conductive plate is located on one side of the opening of the groove of the cover plate support portion. After the conductive plate is broken, the piston squeezes the side of the support portion groove downward in an interference fit manner, and at the same time impacts the broken part of the conductive plate to displace to the other side of the support portion groove. Squeezing the side of the groove downward in an interference fit manner can generate an arc on the extrusion surface after the extrusion and breakage, which helps to extinguish the arc. The impact end of the piston is a sharp-edge structure, and the impact end of the piston is arranged opposite to the breakage-weakening portion of the conductive plate, which is convenient for the piston to break the conductive plate from the breakage-weakening portion. A bending notch is also provided on the conductive plate on one side of the breakage-weakening portion. After the conductive plate is broken, it can slide into the groove of the cover plate support portion along an arc trajectory with the bending notch as the axis.

[0035] Assembly of the present invention: First, send the excitation device from the bottom of the housing to the top position of the housing, so that the limit groove 601 at the upper end of the excitation device is clamped on the limit bump 107 at the top of the housing to ensure that the excitation device will not fall out of the top of the housing. Then insert the partition 5 into the installation grooves on both side walls of the housing, and realize the installation and positioning of the excitation device through the partition 5 and the limit block 107 on the housing. Then put the piston into the housing cavity from the bottom of the housing, so that the guiding ridges (403, 404) on both sides of the piston are located in the guiding grooves on the wall of the housing cavity, and push the piston along the guiding groove to the position of the partition, so that the lower end of the excitation device is located in the groove at the upper end of the piston; at this time, the limit clamping protrusion 405 on the side of the piston is located in the limit groove 106 to limit the position of the piston and keep the piston at the initial position. Then install the conductive plate 2 from the side opening of the housing, so that the conductive plate 2 passes through the long slot 101 on both side walls of the housing, and the clamping protrusion 201 on one side of the conductive plate is clamped in the card slot inside the side wall of the housing to prevent the conductive plate from moving up, down, left and right. Then install the cover plate 7 from the side, install it from the side opening of the housing, so that the clamping ridges 702 at both ends of the supporting part on the cover plate pass through the long guiding groove 103, and the short protrusion 704 at the end of the cover plate is clamped in the long slot 101 for placing the conductive plate. Then push the cover plate into the housing so that the cover plate fits on the side opening of the housing and the outer side of the cover plate is flush with the outer side of the housing; at this time, the limit ridge 703 of the supporting part of the cover plate is embedded in the limit groove inside the side wall of the housing opposite to the cover plate; the clamping protrusions (705, 706) on the cover plate are respectively clamped in the corresponding positions of the clamping grid in the housing to further limit the position of the cover plate. After the cover plate is installed in place, the supporting part of the cover plate closes the bottom opening of the housing and forms a support for the conductive plate inside the housing. The groove of the supporting part is located below the weak point where the conductive plate is disconnected inside the housing, forming a cavity for the displaced conductive plate and the piston to continue to displace to the dead point after the conductive plate is disconnected; the barbs structure arranged on the vertical side of the cover plate is clamped between the side ridges opened on the side wall of the bottom of the housing cavity to further seal the bottom of the housing. When the cover plate is installed in place, fix the cover plate on the housing with screws, and realize the fixation of the cover plate on the housing through the barbs structure and screws on the cover plate.

[0036] The above Figure 2 and Figure 3 In, the excitation device 6 adopts an integrated gas generating device for releasing high-pressure gas. In Figure 4 In, the excitation device adopts a combined structure, and the excitation device includes a combination of a connector 800 and an ignition tube 801. The upper end of the ignition tube 801 is limited at its upper end through the contraction opening of the housing cavity, and the lower end is fixed through the partition. The ignition tube 801 is installed from the bottom opening of the housing, and the connector 800 is installed from the upper opening of the housing so that it is arranged to be connected to the ignition tube at the upper opening of the housing. The gas release end of the ignition tube is located in the groove at the upper end of the piston.

[0037] The gas release end of the excitation device is located in the piston groove, ensuring that when the excitation device generates high-pressure gas, it can drive the piston to displace in the first time. With this structure, the requirement for the sealing of the contact surface between the piston and the cavity is relatively low.

[0038] For the excitation fuse of the present invention, the housing and the cover plate are respectively integrally formed by injection molding. During assembly, only the components need to be directly assembled in place, without the need for additional fixing components; it is light in weight, about 1 / 5 of the weight of the traditional fuse of the same specification and about 2 / 3 of the weight of the ordinary excitation fuse of the same kind; it is small in volume, small in internal resistance, convenient to manufacture and assemble, and shortens the processing cycle.

Claims

1. A small excitation fuse, comprising a housing, and an excitation device, a piston and a conductive plate arranged in sequence in the housing cavity, characterized in that The shell is formed by injection molding, the cavity runs through the upper and lower ends of the shell, and an opening is opened on the side of the shell; the excitation device is installed at the upper end of the cavity to close the upper end opening of the cavity; a push-pull cover plate is provided at the side opening of the shell, the cover plate is an L-shaped drawer structure, and the cover plate closes the lower end opening of the shell cavity and the side opening of the shell; a disconnection weak point is opened on the conductive plate; Long strip grooves are provided on both side walls of the side opening of the shell for installing the conductive plate from the side opening, and a clamping groove is provided on the inner side of the shell opposite to the side opening of the shell; a clamping protrusion that can be clamped into the clamping groove is provided at the position of the conductive plate corresponding to the clamping groove; short convex ridges that can be clamped into the long strip groove to fix the conductive plate are respectively provided at the positions of the cover plate corresponding to the long strip groove; The housing cavity portion above the conductive plate is separated from the housing side opening by a cavity wall; The side of the cover plate below the conductive plate is integrally formed with a support portion for supporting the conductive plate, and the support portion is provided with a first groove for displacement of the piston and the disconnected portion of the conductive plate after the conductive plate is disconnected; The weak point where the conductive plate is disconnected is located on one side of the opening of the first groove on the support part of the cover plate; when the conductive plate is disconnected, the piston moves downward along one side of the first groove of the cover plate support part in an interference fit manner, and at the same time pushes the disconnected part of the conductive plate to move to the other side of the first groove of the cover plate support part.

2. The miniature excitation fuse according to claim 1, characterized in that At least one layer of locking grids is arranged on the outer side surface of the cavity wall located at the side opening of the shell, and locking protrusions that can be locked into the locking grids are respectively arranged at positions on the cover plate corresponding to the locking grids.

3. The miniature excitation fuse according to claim 1 is characterized in that A screw hole seat is arranged on one side of the cavity wall located at the side opening of the shell, and a through hole for the screw to pass through is arranged at a corresponding position on the cover plate.

4. The miniature excitation fuse according to claim 1 is characterized in that A ventilation hole is arranged at the bottom of the first groove.

5. The miniature excitation fuse according to claim 1, characterized in that A convex rib is arranged at the bottom of the first groove.

6. The miniature excitation fuse according to claim 1, characterized in that The two outer sides of the cover plate support part are respectively provided with clamping ridges, and the inner walls on both sides of the side opening of the shell are provided with long guide grooves for clamping the clamping ridges.

7. The miniature excitation fuse according to claim 1, characterized in that Limiting protrusions are arranged at intervals at the upper end opening of the cavity in the shell, and corresponding limiting grooves are arranged on the excitation device; an installation groove for the partition supporting the excitation device to pass through is opened in the cavity below the excitation device.

8. The miniature excitation fuse according to claim 1, characterized in that Limiting grooves are arranged at intervals on the inner wall of the shell cavity above the conductive plate, and corresponding limiting cams which can be retracted under pressure are arranged at the positions of the limiting grooves corresponding to the outer circumference of the piston. When the piston is installed in the shell cavity, the limiting cams are locked in the limiting grooves; when the piston is driven by the excitation device, the piston can overcome the limit of the limiting cams and move.

9. The miniature excitation fuse according to claim 1, characterized in that The piston comprises an impact end, and the impact end is arranged corresponding to the disconnected weak point of the conductive plate.

10. The miniature excitation fuse according to claim 1, characterized in that A second groove is provided on the end surface of the piston in contact with the excitation device, and the gas release end of the excitation device is located in the second groove.

11. The miniature excitation fuse according to claim 1, characterized in that The excitation device includes an ignition tube and a connecting tube connected together; the connecting tube is located at the opening of the upper end of the shell, and the ignition tube is located in the cavity between the connecting tube and the piston; the upper end of the ignition tube is limited by the cavity contraction mouth, and the lower end is supported and positioned by a partition or a piston inserted in the mounting groove in the shell cavity.

12. The miniature excitation fuse according to claim 1, characterized in that An exhaust hole is provided at the contact surface between the piston and the housing cavity. When the piston is in the initial position, the piston covers the exhaust hole. When the piston is displaced to disconnect the conductive plate, the piston leaves the exhaust hole.

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