Self-excitation fuse

Abstract

The invention belongs to the field of circuit protection, and particularly relates to a self-excitation fuse which comprises a shell, a first conductive part of a cylindrical structure, a first melt, a second conductive part of a cylindrical structure, a first excitation source and a cut-off device, and the first conductive part, the first melt and the second conductive part are sequentially connected in series. The first excitation source and the second melt are respectively connected in parallel at two ends of the first melt; the wiring terminals at two ends of the shell are respectively and electrically connected with the first conductive piece and the second conductive piece; the first excitation source acts according to a trigger signal generated when the first melt is fused, and after the cutting device is driven to cut off an electrical loop where the first conductive part and the second conductive part are located, the second melt is fused or cut off by the cutting device. The circuit breaker is high in breaking capacity, small in product size, high in impact resistance and practical and small in size.

Description

Technical Field

[0001] The present invention belongs to the field of circuit protection, and specifically refers to a self-excited fuse for circuit protection. Background Art

[0002] With the development of new energy technologies and the continuous progress of energy storage battery technologies, the charging current and charging voltage are constantly increasing, which puts forward the requirements for fuses to interrupt higher voltages and carry larger currents. According to the design principle of traditional fuses, to carry large currents, more fuse elements need to be connected in parallel, and the length of the fuse for interrupting higher voltages will increase, resulting in a significant increase in the volume and power consumption of the fuse, which is not conducive to the development of new energy technologies. To solve the above problems, currently in the market, the breaking capacity of fuses is improved through excitation, but there is still the problem of large volume. For example, a highly reliable active and passive integrated protection device disclosed in Chinese Patent No. 2022215716777 has a high breaking capacity, but the length of the conductive parts is long and the product volume is large, making it inapplicable to places that require miniaturization and high breaking capacity. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a self-excited fuse, which can reduce the product volume, improve the impact resistance of the product, and reduce the strength of the product shell while improving the breaking capacity.

[0004] To solve the above technical problem, the technical solution provided by the present invention is a self-excited fuse, which includes a housing, a terminal, a first conductive part, a second conductive part, a first fuse element, a second fuse element, a first excitation source, and a cutting device arranged in the housing;

[0005] Both the first conductive part and the second conductive part are in a cylindrical structure, arranged in sequence along the axial direction of the cylindrical structure and disposed in the housing. One adjacent end of the first conductive part and the second conductive part is connected in series through the first fuse element; both the first excitation source and the cutting device are located in the cylindrical structure of the first conductive part; the terminals at both ends of the housing are electrically connected to the first conductive part and the second conductive part respectively, and the terminals are fixedly arranged at both ends of the housing;

[0006] The first excitation source and the second fuse element are respectively connected in parallel across both ends of the first fuse element to form a first excitation source parallel branch and a second fuse element parallel branch; an arc extinguishing medium is filled around the second fuse element;

[0007] During normal operation, the current flows through the first conductive part, the first fuse element, and the second conductive part;

[0008] When an overload current or a short - circuit current occurs, the first fuse melts, and the voltage signal across the disconnected first fuse is used as the trigger signal for the first excitation source. After the first excitation source is triggered to act and release the driving force to drive the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, the second fuse melts or is disconnected by the cutting device.

[0009] Preferably, the first excitation source can also receive an external trigger signal. When an abnormal situation occurs, the first excitation source acts according to the received external trigger signal, releases the driving force, drives the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then the second fuse melts or is disconnected by the cutting device;

[0010] It further includes a second excitation source that can receive an external trigger signal; when the first excitation source fails, the second excitation source acts according to the received external trigger signal, releases the driving force to drive the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then disconnects the second fuse.

[0011] Preferably, a switching element is respectively connected in series on the parallel branch of the first excitation source and the parallel branch of the second fuse; or, a switching element is connected in series on the parallel branch of the first excitation source or the parallel branch of the second fuse; during normal operation, the switching element is not conducting; when the first fuse melts, the switching element conducts, making the parallel branch where it is located conducting.

[0012] Preferably, the switching element is an electronic switching element. During normal operation, the electronic switching element is not conducting; when the voltage across the first fuse exceeds a set threshold after the first fuse melts, the electronic switching element is triggered to conduct.

[0013] Preferably, the electronic switching element is a transient voltage suppression diode.

[0014] Preferably, the switching element connected in series on the parallel branch of the second fuse is a mechanical switching element. In the normal operating state, the mechanical switching element is in an open state; when the first fuse melts and the first excitation source acts to release the driving force, while the driving force drives the cutting device to act, it can also drive the mechanical switching element to close, conducting the parallel branch of the second fuse.

[0015] Preferably, the connecting wire of the parallel branch of the first excitation source is located on the displacement path of the cutting device. When the cutting device cuts off the first conductive member and the second conductive member, it can cut off the connecting wire of the parallel branch of the first excitation source.

[0016] Preferably, a part of the inner walls of the first and second conductive members of the cylindrical structure in the circumferential direction, or a part of the circumferential direction at the adjacent ends, respectively extend towards each other along the radial direction of the cylindrical structure to form force-bearing surfaces; the first melt is connected in series between the force-bearing surfaces of the first and second conductive members; the second melt is located in the cylindrical structure of the second conductive member.

[0017] Preferably, the force-bearing surfaces are respectively located at the ends of the adjacent ends of the first and second conductive members, and the force-bearing surfaces of the first and second conductive members are located in the same plane and are arranged in a staggered manner.

[0018] Preferably, a first inner housing is fixedly connected in the first conductive member, and one end of the first inner housing is in contact and cooperation with the wiring terminal; a second inner housing is arranged in the second conductive member, the first inner housing and the second inner housing are butted, the force-bearing surfaces of the first and second conductive members are clamped between the butted end faces of the first inner housing and the second inner housing, the first melt is located in the first inner housing and the second inner housing; the first excitation source and the cutting device are arranged in the first inner housing; the second melt is located between the second inner housing and the second conductive member; when the first excitation source is triggered to act, it drives the cutting device to displace along the first inner housing and the second inner housing, and disconnects the first and second conductive members from the force-bearing surface; the second melt melts or is disconnected by the cutting device.

[0019] Preferably, the cutting device includes a first inner sleeve and a second inner sleeve connected in butt joint, the first inner sleeve is located in the first inner housing, and the second inner sleeve is located in the second inner housing; a closed cavity is formed in the butted first inner sleeve and second inner sleeve, and an arc extinguishing medium is filled in the first inner sleeve and the second inner sleeve; the force-bearing surfaces of the first and second conductive members are clamped between the butted surfaces of the first inner sleeve and the second inner sleeve, or a part of the force-bearing surface of the first conductive member and the first melt or a part of the force-bearing surface of the second conductive member and the first melt are clamped between the butted surfaces of the first inner sleeve and the second inner sleeve, so that the neck of the first melt is located in the arc extinguishing medium in the first inner sleeve and the second inner sleeve; when the first excitation source is triggered to act, it releases a driving force, drives the first inner sleeve and the second inner sleeve to displace relative to the first inner housing and the second inner housing, and simultaneously disconnects the first and second conductive members, or simultaneously disconnects the first melt, and the first conductive member or the second conductive member, and then the first inner sleeve and the second inner sleeve penetrate through the fracture between the first and second conductive members.

[0020] Preferably, when one end of the second inner housing is open and the other end is closed, and the open end is docked with the first inner housing, the second melt is melted; when both ends of the second inner housing are through, a support guiding cylinder is provided on the inner end face of the terminal where the second conductive member is located, and the support guiding cylinder is docked with the second inner housing to form a displacement channel, and the second melt passes through the docking surface between the support guiding cylinder and the second inner housing; when the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, the second melt is disconnected.

[0021] Preferably, it further includes a melt disconnection assembly; the melt disconnection assembly includes a push block and a guiding block, the guiding block is arranged at one end of the support guiding cylinder facing the cutting device, one end of the push block is located in the second inner housing, and the other end is supported by the guiding block; the second melt passes through the docking surface between the push block and the guiding block and is clamped by the push block and the guiding block; when the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, the cutting device drives the push block and the guiding block to displace, so as to disconnect the second melt.

[0022] Preferably, the positions of the first conductive member and the second conductive member corresponding to the cutting device are weak points for disconnection.

[0023] Preferably, an arc extinguishing medium is filled around the first melt.

[0024] Preferably, a pressing piston is arranged between the barrel wall of the first inner housing and the first conductive member, and the cavity where the pressing piston is located is communicated with the cavity where one end of the first excitation source releases driving force through an air duct; one end of the second melt is electrically connected to the second conductive member, and the other end passes through the first conductive member and is located on the displacement path of the pressing piston and is insulated from the first conductive member, so that the parallel branch of the second melt is not conducting; a support guiding cylinder corresponding to the second inner housing is arranged between the second inner housing and the terminal, and one end of the second inner housing corresponding to the support guiding cylinder is an open end, and the second melt passes through between the open end of the second inner housing and the support guiding cylinder; when the first excitation source releases driving force, while driving the cutting device to displace, it drives the pressing piston to displace, and the pressing piston drives one end of the second melt located on the displacement path of the pressing piston to be electrically connected to the first conductive member, so that after the parallel branch of the second melt is conducting, when the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, the second melt is disconnected.

[0025] For the fuse of the present invention, the first conductive member and the second conductive member adopt a cylindrical structure. The advantages of the cylindrical structure are as follows: it can increase the overall current-carrying area of the conductive member, improve the current-carrying capacity of the two conductive members, and the fuse wire in conductive series between the two conductive members can adopt a fuse wire with a large current-carrying capacity, so as to improve the overall current-carrying capacity of the self-excited fuse. The cylindrical structure increases the strength of the outer shell. By cutting the fuse wire between the cylindrical structures with a piston, the self-excited fuse can be directly connected to the circuit to be protected by using the wiring method of a conventional fuse.

[0026] The excitation source and the cutting device are arranged in the first conductive member. A second fuse wire is connected in parallel between the first conductive member and the second conductive member. The small overload current can be interrupted by the first fuse wire, and the large overload current can be interrupted by the parallel-connected second fuse wire. Through the second excitation source, on the basis of interrupting the overload and short-circuit currents, it can also be interrupted under abnormal conditions to achieve zero-current interruption of the main circuit.

[0027] The excitation source and the cutting device are arranged in the conductive member of the cylindrical structure. Most of the impact energy brought by the release of the driving force of the excitation source is borne by the conductive member, avoiding the outer shell directly bearing the impact energy, and the strength requirement of the outer shell can be reduced.

[0028] For the fuse of the present invention, on the basis of improving the breaking capacity, the volume is reduced through the conductive member of the cylindrical structure, making the fuse structure more compact and having stronger impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the principle structure of the present invention.

[0030] Figure 2 is Figure 1 a schematic diagram of the principle structure with a voltage trigger element added on the basis.

[0031] Figure 3 is Figure 1 a schematic diagram of the principle structure in which the connecting wire of the first excitation source is located on the displacement path of the cutting device on the basis.

[0032] Figure 4 is Figure 1 a schematic diagram of the principle structure with a switch device added on the basis.

[0033] Figure 5 is Figure 1 a schematic diagram of the principle structure with a second excitation source added on the basis.

[0034] Figure 6 is a cross-sectional view of the specific structure of the product of the present invention.

[0035] Figure 7 is a three-dimensional structure diagram of the first conductive member, the first fuse wire, and the second conductive member.

[0036] Figure 8 Yes Figure 7 is a schematic cross-sectional structure diagram of

[0037] Figure 9 It is a schematic structure diagram in which one end of the second melt parallel branch is not directly conductively connected to the first conductive member, and the second melt is connected in parallel to the electrical circuit where the first conductive member and the second conductive member are located by the displacement of the pressing piston.

[0038] Reference numerals:

[0039] housing 100, terminal 101, end plate 1011, connecting plate 1012, first inner housing 102, limiting rib 1021, second inner housing 103, second inner sleeve 104, closed cavity 105, support guide tube 106, push block 107, first conductive member 10, end portion 11, end plate 12, notch 13, second conductive member 20, end portion 21, end plate 22, notch 23, first melt 30, second melt 40, voltage trigger element 41, mechanical switch element 42, first excitation source 50, voltage trigger element 51, connecting wire 52, cutting device 60, second excitation source 70, pressing piston 80, opening 81. Detailed implementation manners

[0040] The self-excited fuse of the present invention includes a housing, a terminal, a first conductive member, a second conductive member, a first melt, a second melt, a first excitation source, and a cutting device disposed in the housing;

[0041] Both the first conductive member and the second conductive member are of a cylindrical structure, are arranged in sequence along the axial direction of the cylindrical structure and are disposed in the housing. One adjacent end of the first conductive member and the second conductive member is connected in series through the first melt; both the first excitation source and the cutting device are located in the cylindrical structure of the first conductive member; the terminals located at both ends of the housing are respectively conductively connected to the first conductive member and the second conductive member, and the terminals are fixedly disposed at both ends of the housing;

[0042] The first excitation source and the second melt are respectively connected in parallel across both ends of the first melt to form a first excitation source parallel branch and a second melt parallel branch; an arc extinguishing medium is filled around the second melt;

[0043] During normal operation, current flows through the first conductive member, the first melt, and the second conductive member;

[0044] When an overload current or a short-circuit current occurs, the first melt fuses, and the voltage signal across the disconnected first melt is used as the trigger signal for the first excitation source. The first excitation source is triggered to act, releases a driving force, drives the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then the second melt fuses or is disconnected by the cutting device;

[0045] The first excitation source can also receive an external drive signal. When an abnormal situation occurs: The first excitation source releases a driving force according to the received external trigger signal and trigger action, drives the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then the second fuse melts or is disconnected by the cutting device;

[0046] When the first excitation source fails, the cutting device can also be driven by the driving force released after being triggered by a second excitation source that can receive an external drive signal. After disconnecting the electrical circuit where the first conductive member and the second conductive member are located, the second fuse is disconnected.

[0047] In the above technical solution, the first excitation source must first be connected in parallel with both ends of the first fuse. Then, in case of overload or short - circuit current, the first fuse melts. A high - impedance state is formed at the break of the first fuse, and the voltage at the break of the first fuse will instantaneously increase. Only the instantaneously increased voltage signal can trigger the first excitation source, that is, the temperature instantaneously rises to the ignition temperature, and the gas - generating agent in the first excitation source undergoes a chemical reaction to release high - pressure gas as the driving force, and drives the mechanical disconnection of the electrical circuit through the driving force. The trigger signal generated by the melting of the first fuse is the trigger signal generated by the fuse itself, so it becomes a self - excited fuse. When disconnecting the electrical circuit, the second fuse connected in parallel can melt and extinguish the arc by heat, or can be designed as required so that the cutting device disconnects the second fuse after continuing to displace after disconnecting the electrical circuit.

[0048] However, in an abnormal situation, such as when a vehicle collides, at this time, the current in the main circuit is not overloaded or short - circuited, so the first fuse cannot melt, and the fuse does not have the function of disconnecting the electrical circuit. To solve this special situation, the first excitation source is connected in parallel on the basis of the first fuse, and a connection end that can be connected to a trigger circuit controlled by a client control system outside the fuse is connected to the signal receiving end of the first excitation source. When in use, according to the needs of the client, it can be connected to the external trigger circuit through the connection end. In an abnormal situation, such as when a vehicle collides, the pressure sensor sends the monitoring data to the client control system. The client control system issues an active trigger instruction according to the analysis and judgment, sends an active trigger signal to the first excitation source through the external trigger circuit, so that the first excitation source acts when the first fuse has not melted, releases the driving force, and drives the cutting device to mechanically disconnect the electrical circuit. When disconnecting the electrical circuit, the second fuse connected in parallel can melt and extinguish the arc by heat, or can be designed as required so that the cutting device disconnects the second fuse after continuing to displace after disconnecting the electrical circuit. Active protection of the main circuit is achieved.

[0049] The above - mentioned first excitation source acts according to the voltage signal at the break of the first fuse as the trigger signal or receives an external trigger signal to ensure the triggering of the first excitation source in different situations.

[0050] However, when the first excitation source itself fails, the entire excitation fuse cannot work properly for circuit protection. Therefore, by setting a backup second excitation source, the second excitation source receives the trigger signal sent by the trigger circuit controlled by the client control system and acts, driving the cutting device to disconnect the electrical circuit while disconnecting the second fuse element.

[0051] The situation where the second excitation source receives the trigger signal: The client control system monitors the current and abnormal conditions of the main circuit and feeds back the monitoring information to the client control system. When there is overload, short-circuit current or abnormal conditions in the main circuit, within a certain period of time after the client control system receives the monitoring information, when it is detected that the main circuit has not been disconnected, it proves that the first excitation source has failed. At this time, the client control system sends an instruction to the trigger circuit according to the analysis and judgment, and sends a trigger signal to the second excitation source through the trigger circuit. The second excitation source releases the driving force, drives the cutting device to disconnect the electrical circuit and then disconnects the second fuse element to achieve main circuit protection.

[0052] The second excitation source is a backup for the first excitation source to ensure that the main circuit is protected when the first excitation source fails.

[0053] The electrical circuit where the first conductive member and the second conductive member are located refers to the circuit formed by sequentially connecting the first conductive member, the first fuse element and the second conductive member in series.

[0054] The main circuit refers to the circuit to be protected, that is, the circuit formed by sequentially connecting the first conductive member, the first fuse element and the second conductive member in series can be connected to the circuit to be protected in series.

[0055] The excitation source of the present invention is a gas generating device (MGG), which ignites under the electrical signal (voltage signal) of the trigger signal and releases high-pressure gas as the driving force.

[0056] See Figure 1 , the fuse of the present invention includes a first conductive member 10, a second conductive member 20, a first fuse element 30, a second fuse element 40, a first excitation source 50, and a cutting device 60. The first conductive member 10 and the second conductive member 20 are connected in series through the first fuse element 30 to form a series circuit. The first excitation source 50 and the cutting device 60 are located on one side of the series circuit formed by the first conductive member 10, the second conductive member 20, and the first fuse element 30. The first excitation source 50 is electrically connected to the first conductive member 10 and the second conductive member 20 located at both ends of the first fuse element 30 through a wire to form a first excitation source parallel branch. The first excitation source parallel branch collects the voltage signal across the first fuse element. Only when the first fuse element 30 melts, the voltage signal across the break of the first fuse element 30 can trigger the first excitation source 50 to act, release high-pressure gas as the driving force, and drive the cutting device 60 to cut off the first conductive member and the second conductive member located at both ends of the first fuse element 30 to disconnect the circuit.

[0057] Both ends of the second melt 40 are electrically connected to the first conductive member 10 and the second conductive member 20 at both ends of the first melt 30, so that the second melt 40 is connected in parallel across the first melt 30 to form a second melt parallel branch. An arc extinguishing medium is filled around the second melt 40. The second melt 40 filled with the arc extinguishing medium can be replaced by a thermal fuse.

[0058] The first melt 30 is a melt with low impedance. The series circuit formed by being connected in series with the first conductive member 10 and the second conductive member 20 can be connected to the main circuit in series. The impedance of the second melt 40 is much greater than that of the first melt 30. The first excitation source 50 is a pure impedance device, and its impedance is much greater than the impedances of the first melt and the second melt.

[0059] Under normal operating conditions, current flows through the first conductive member 10, the first melt 30, and the second conductive member 20, and only a very small part flows through the second melt 40 and the first excitation source 50.

[0060] In case of overload current or short - circuit current, the first melt 30 fuses, forming a high - impedance state at the break of the first melt 30. The voltage across the break of the first melt 30 instantaneously rises. The voltage signal at the break of the first melt 30 is used as a trigger signal to trigger the first excitation source 50 to actuate and ignite, releasing a large amount of high - pressure gas as a driving force to drive the first excitation source 50 to cut off the first conductive member and the second conductive member at both ends of the first melt, disconnecting the main circuit; when the main circuit is disconnected, almost all of the current flows through the second melt 40, and the second melt 40 fuses to completely disconnect the circuit.

[0061] See Figure 2 On the basis of Figure 1 In the excitation source parallel branch and the second melt parallel branch, switching elements are respectively connected in series. The switching elements are electronic switching elements, such as voltage trigger elements (41, 51). When the voltage across the first melt 30 is higher than the set threshold, the voltage trigger elements (41, 51) conduct. In the normal operating state, current flows through the first conductive member 10, the first melt 30, and the second conductive member 20. Due to the existence of the voltage trigger elements (41, 51), the parallel branch where the second melt 40 and the first excitation source 50 are located is not conductive, and no current flows through the second melt 40 and the first excitation source 50, further improving the stability of the product and reducing the power consumption of the product. The voltage trigger element is preferably a transient voltage suppression diode (TVS tube).

[0062] See Figure 3 On the basis of Figure 1On the basis of this, the connecting wire 52 of the first excitation source parallel branch of the first excitation source 50 is arranged in the displacement path of the cutting device 60. After the first excitation source 50 operates, the released driving force drives the cutting device 60 to displace, cutting the connecting wire, disconnecting the first excitation source parallel branch, and at the same time cutting the first conductive member and the second conductive member at both ends of the first melt. Disconnecting the first excitation source parallel branch enables the first excitation source to only bear high voltage when triggered and no longer bear high voltage after operation, which can reduce the withstand voltage requirement for the first excitation source. There is a sufficient insulation distance between the connecting wire of the first excitation source parallel branch and the conductive member, and the insulation distance from the conductive member must be maintained after the connecting wire is cut.

[0063] See Figure 4 , on the basis of Figure 1 , a switching element is connected in series on the second melt parallel branch. The switching element is a mechanical switching element 42. In the initial state and normal working state, the mechanical switching element 42 is in the normally open state. Before the cutting device 60 is driven to displace and cut the first conductive member and the second conductive member at both ends of the first melt 30, the mechanical switching element 42 is driven to close, connecting the second melt parallel branch, and connecting the second melt 40 to the main circuit in parallel. After the cutting device 60 cuts the first conductive member and the second conductive member, the second melt 40 fuses, completely disconnecting the circuit.

[0064] The structure of the mechanical switching element 42 may include a static conductive end and a conductive elastic piece that is misaligned and open, so that the mechanical switching element 42 remains in the normally open state in the initial state and normal working state; when the cutting device displaces, the cutting device drives the conductive elastic piece to displace and conductively contact the static conductive end, realizing the closing of the mechanical switching element 42.

[0065] See Figure 5, a second excitation source 70 is also connected in parallel in the fuse. The second excitation source 70 can be connected to a trigger control device outside the fuse, and a trigger signal is sent to the second excitation source 70 through the external trigger control device. The trigger signal of the first excitation source 50 is limited to when there is an overload current or a short-circuit current in the circuit, causing the first fuse element to melt. When the first fuse element melts, the voltage across its two ends instantaneously increases, and the increased voltage signal serves as the trigger signal for the first excitation source 50. However, the triggering of the second excitation source 70 is not limited by this. The external trigger control device can send a trigger signal to the second excitation source 70 when there is an overload current or a short-circuit current, or can also send a trigger signal to the second excitation source 70 in abnormal situations (such as in traffic accidents like car collisions). The second excitation source 70 triggers an action according to the received trigger signal, releases a driving force, and can drive the cutting device 60 to displace and cut off the first conductive member and the second conductive member, and then cut off the second fuse element in sequence. Therefore, in abnormal situations, when the current in the circuit does not increase, after the first conductive member and the second conductive member are cut off, the second fuse element cannot melt either. In such a case, the second fuse element must be cut off. Therefore, there is a difference in the magnitudes of the driving forces released by the first excitation source and the second excitation source, and the driving force released by the second excitation source is greater than the driving force released by the first excitation source.

[0066] The above Figures 1 to 5 is only a schematic diagram of the principle structure. The following gives specific structural embodiments for detailed description, taking Figure 1 the principle as an example for illustration.

[0067] Refer to Figure 6 , the fuse of the present invention includes a housing 100, a terminal 101, a first conductive member 10, a second conductive member 20, a first fuse element 30, a second fuse element 40, a first excitation source 50, and a cutting device 60.

[0068] The housing 100 is a cylindrical structure with both ends penetrating, and is made of an insulating material. The first conductive member 10 and the second conductive member 20 are sequentially arranged in the housing 100 along the length direction, and a first fuse element 30 is connected in series at one adjacent end of the first conductive member 10 and the second conductive member 20. The first conductive member 10 and the second conductive member 20 are arranged in interference fit with the inner wall of the housing 100, and the positioning of the first conductive member and the second conductive member in the housing 100 is achieved through the interference fit. The first conductive member and the second conductive member can also be positioned by gluing or a limiting structure. For example, the terminal is fixedly connected to the housing, and an insulating ring is arranged between the adjacent ends of the first conductive member and the second conductive member, and the positioning of the first conductive member and the second conductive member is achieved through the terminal and the insulating connection.

[0069] Refer to Figure 7 and Figure 8, both the first conductive member 10 and the second conductive member 20 are cylindrical structures, and the cylindrical structure has a hollow portion that penetrates through both ends. One end (11, 21) of the first conductive member 10 and the second conductive member 20 that are adjacent is a partially enclosed structure. The partially enclosed structure is provided with partial end plates (12, 22) at the end face to enclose part of the end face, and a notch (13, 23) is provided at the unenclosed end face. The end plates (12, 22) are the force-bearing surfaces. The partially enclosed structures of the adjacent ends (11, 21) of the first conductive member 10 and the second conductive member 20 are arranged in a staggered alignment, so that the partially enclosed structures of the first conductive member 10 and the second conductive member 20 are in the same plane, and a gap is reserved between one end (11, 21) of the partially enclosed structures of the first conductive member 10 and the second conductive member 20. The first melt 30 is located at the gap between the ends (11, 21) of the first conductive member 10 and the second conductive member 20, electrically connecting the first conductive member 10 and the second conductive member 20 in series to form a series circuit inside the fuse. The non-adjacent ends of the first conductive member 10 and the second conductive member 20 are respectively located at both ends of the housing 100.

[0070] Terminal blocks 101 are respectively provided at both ends of the housing 100. The terminal blocks 101 are made of conductive materials. The terminal blocks 101 include a conductive end cap 1011 and a connecting plate 1012. The connecting plate 1012 and the end cap 1011 are integrally connected or connected by welding. The end cap 1011 of the terminal block 101 is electrically connected to one end of the first conductive member 10 and the second conductive member 20 located at both ends of the housing 100, and encloses the ends of the housing 100 and the first and second conductive members. The terminal block is the connection end of the fuse, and can be connected to the electrical circuit to be protected, that is, the main circuit, by using the wiring method of the existing thermal fuse.

[0071] A first inner housing 102 is provided in the first conductive member 10, and a second inner housing 103 is provided in the second conductive member 20. At least one circle of limiting ridges 1021 is provided on the outer periphery of the first inner housing 102, and the limiting ridges 1021 are in interference fit with the inner wall of the first conductive member 10. In other embodiments, the first inner housing and the first conductive member can be in clearance fit or transition fit to facilitate assembly. One end of the first inner housing 102 abuts against the terminal 101, and one end abuts against the ends (11, 21) of the adjacent first conductive member 10 and second conductive member 20, forming the positioning of the first inner housing 102. One end of the second inner housing 103 is open and one end is closed. Limiting ridges are provided on the outer peripheral wall of the second inner housing 103, and the limiting ridges are in interference fit with the inner wall of the second conductive member to realize the positioning of the second inner housing. In other embodiments, the second inner housing and the second conductive member can be in clearance fit or transition fit to facilitate assembly. The open end of the second inner housing 103 abuts against the ends (11, 21) of the adjacent first conductive member 10 and second conductive member 20, and the portions of the first inner housing 102 and the second inner housing 103 located at the gap of the ends (11, 21) are butted, that is, the end face portions of the adjacent ends of the first inner housing 102 and the second inner housing 103 are butted and contacted. The first inner housing 102 and the second inner housing 103 at the end face at the ends (11, 21) are respectively in contact with the end face of the ends (11, 21), so that a part of the end face of the ends (11, 21) and the first melt are located in the cavity formed by the first inner housing 102 and the second inner housing 103. The diameters of the inner walls and outer walls of the first inner housing 102 and the second inner housing 103 are the same.

[0072] The first excitation source 50 is fixedly arranged in the first inner housing 102, and its signal connection end is electrically connected to the first conductive member 10 and the second conductive member 20 at both ends of the first melt 30 through a wire.

[0073] The cutting device 60 is a first inner sleeve 60, which is arranged in the first inner housing 102 and is attached to the inner wall of the first inner housing 102. When driven by the driving force released by the first excitation source 50, the first inner sleeve 60 can displace relative to the first inner housing 102. One end of the first inner sleeve 60 is open and one end is closed. Its open end is the impact end, which is located at the stress surface of one end where the first conductive member and the second conductive member are connected in series with the first melt, that is, at the partially closed structure. A breaking weak point is provided at the stress surface of the ends of the first conductive member and the second conductive member corresponding to the impact end of the first inner sleeve 60.

[0074] A second inner sleeve 104 is disposed in a second inner housing 103 of the second conductive member 20. One end of the second inner sleeve 104 is open and the other end is closed. The open end of the second inner sleeve 104 abuts against the force-receiving surface at one end where the first conductive member and the second conductive member are connected in series with the first melt, and is fixedly butted with the first inner sleeve 60. After the first inner sleeve 60 and the second inner sleeve 104 are butted, a closed cavity 105 is formed in the first inner sleeve 60 and the second inner sleeve 104, and an arc extinguishing medium is filled in the closed cavity 105. The first melt 30 is located in the arc extinguishing medium in the closed cavity formed after the first inner sleeve 60 and the second inner sleeve 104 are butted.

[0075] When there is an overload current or a short-circuit current, the first melt 30 fuses first. Since the length of the first melt 30 is very short, that is, the distance between the adjacent ends of the first conductive member and the second conductive member at the connection of the first melt 30 is very short. When the first melt 30 fuses, a high-impedance state is formed at the break of the first melt 30, and the voltage across the two ends of the first melt 30 instantaneously rises to reach the set threshold value capable of triggering the first excitation source 50. The first excitation source 50 then triggers ignition, and the gas-generating agent reacts to release a large amount of high-pressure gas as a driving force, driving the displacement of the first inner sleeve 60 and the second inner sleeve 104, and cutting off the first conductive member and the second conductive member from the weak break at the force-receiving surface of the first conductive member and the second conductive member located at both ends of the first melt 30. The disconnected portions of the first conductive member and the second conductive member and the disconnected portion of the first melt connected thereto are displaced together with the first inner sleeve, the second inner sleeve and the arc extinguishing medium therein until the bottom of the second inner housing 103. At this time, the first inner sleeve is located between the disconnected ends of the first conductive member and the second conductive member, completely isolating the first conductive member and the second conductive member, and improving the insulation after the first conductive member and the second conductive member are disconnected.

[0076] A second melt 40 is located in the second conductive member 20 and in the cavity between the inner wall of the second conductive member and the outer peripheral surface of the second inner housing 103. The two ends of the second melt 40 are respectively conductively connected to the first conductive member and the second conductive member, forming a second melt parallel branch.

[0077] When the first melt fuses, the current flowing through the first conductive member, the first melt and the second conductive member is transferred to flow through the second melt 40. Since the impedance of the second melt 40 is much greater than the impedance of the first melt, the first conductive member and the second conductive member, the second melt 40 plays a current-limiting role. After the first conductive member and the second conductive member are disconnected by the first inner sleeve, the second melt 40 fuses.

[0078] Since the first melt is located in the arc extinguishing medium, the arc generated when the first melt fuses is extinguished by the arc extinguishing medium. When the second melt 40 fuses, since the current has been reduced by several times, the arc generated when the second melt 40 fuses is very small, and it can be directly extinguished by air.

[0079] Of course, the cavity where the second melt 40 is located can also be filled with an arc extinguishing medium to improve the arc extinguishing ability.

[0080] In the above embodiments, the cutting device cuts off the first conductive member and the second conductive member. In other embodiments, the cutting device can cut off only the first conductive member or the second conductive member.

[0081] In other embodiments, the first inner sleeve and the second inner sleeve do not serve as a cutting device, but only as an arc extinguishing cavity filled with an arc extinguishing medium. The first inner sleeve and / or the second inner sleeve are press-fitted into the first inner housing and the second inner housing through the limiting ridges provided on the outer periphery. Additionally, a piston is provided around the first inner sleeve in the first inner and outer housing. The piston is similar to a cap-like structure, with the closed end facing the first excitation source and the open end facing the stress surfaces of the first conductive member and the second conductive member. After the piston passes through the limiting ridges of the first inner sleeve, it can displace relative to the limiting ridges of the first inner sleeve and the second inner sleeve. The impact end of the piston is located on the stress surface of the first conductive member and / or the second conductive member between the first inner sleeve and the first inner and outer housing. When the first excitation source is triggered to act, the piston displaces, and the first conductive member and / or the second conductive member are disconnected from the stress surface.

[0082] Through the tubular first conductive member and the second conductive member, the impact force generated when the first excitation source releases high-pressure gas is borne by the tubular first conductive member and the second conductive member. The first conductive member and the second conductive member are made of a metal material with a certain thickness. Therefore, the impact resistance of the product is improved, and at the same time, the strength requirement for the outer shell 100 is reduced.

[0083] By the fusing of the first melt with a very short length, a trigger signal is provided for the first excitation source, enabling the fuse product to achieve passive excitation. The length of the first melt is very short. By fusing the first melt, combining with the excitation source and the cutting device to disconnect the first conductive member and the second conductive member, while improving the breaking capacity, the power consumption of the product is reduced.

[0084] A closed first inner sleeve and a second inner sleeve are arranged around the first melt, and an arc extinguishing medium is filled. When the first melt fuses, the arc generated is extinguished by the arc extinguishing medium. After the first conductive member and the second conductive member are disconnected, the disconnected part displaces together with the arc extinguishing medium away from the first conductive member and the second conductive member. At the same time, auxiliary arc extinguishing is achieved by the fusing of the second melt. Through the first melt, the second melt, the arc extinguishing medium, etc., the breaking capacity of the fuse is improved, making the breaking more reliable.

[0085] In the above embodiments, the second melt 40 fuses. In other embodiments, the second melt 40 can be cut off. Refer to Figure 9, on the basis of the above embodiments, a cavity is formed by the limiting convex rib 1021 of the first inner housing 102, the barrel wall of the first conductive member, and a partial closed end face of the first conductive member. A pressing piston 80 is arranged in the cavity, and the cavity where the pressing piston 80 is arranged communicates with the cavity where the driving force release end of the first excitation source 50 is located through an opening 81. A through hole for the second melt 40 to pass through is formed at the force-receiving surface of the first conductive member corresponding to the pressing piston 80.

[0086] One end of the second inner housing 103 close to the second melt 40 is an open end. A support guiding cylinder 106 is fixedly connected to the inner end face of the wiring terminal 101 electrically connected to the second conductive member. The support guiding cylinder 106 is arranged corresponding to the second inner housing 103, and the support guiding cylinder 106 is provided with a displacement channel communicating with the second inner and outer housing 103. A pushing block 107 is arranged in the second inner housing 103 between the second inner sleeve 104 and the support guiding cylinder 106. The pushing block 107 abuts against the open end of the displacement channel of the support guiding cylinder 106. The second melt 40 passes through the butting surface of the pushing block 107 and the displacement channel of the support guiding cylinder 106. Initial position positioning of the pushing block 107: A limiting convex block is arranged on the outer periphery of the pushing block 107, and the limiting convex block is located at the limiting notch at the open end of the displacement channel of the support guiding cylinder, forming the initial position positioning of the pushing block 107.

[0087] One end of the second melt 40 is fixedly connected and electrically connected to the second conductive member, and the other end is bent or connected with a conductive elastic sheet after passing through the through hole at the force-receiving surface of the first conductive member; the bent end of the second melt 40 or the end connected with the conductive elastic sheet is located above the force-receiving surface of the first conductive member, is insulated from the first conductive member, and the end of the second melt 40 after bending is located on the displacement path of the pressing piston 80.

[0088] When the first excitation source 50 is triggered to release the driving force, first, the driving force drives the first inner sleeve and the second inner sleeve to displace, and at the same time, the driving force drives the pressing piston 80 to displace. Before the electrical circuit where the first conductive member and the second conductive member are located is disconnected, the pressing piston 80 drives the bent end of the second melt 40 or the end connected with the conductive elastic sheet to be in conductive contact with the first conductive member, and connects the second melt in a parallel manner to the electrical circuit where the first conductive member, the first melt, and the second conductive member are located.

[0089] Then, after the first inner sleeve and the second inner sleeve disconnect the first conductive member and the second conductive member, the pushing block 107 is pushed to displace, cutting off the second melt 40. In this embodiment, the pushing block may not be provided, and the second melt can be directly cut off by a cutting device. In this embodiment, in the normal working state, the second melt is not connected to the electrical circuit, and only when an overload current, a short circuit, or an abnormal situation occurs, the second melt 40 will be connected to the electrical circuit. Such a structure can further reduce the power consumption of the fuse. In Figure 9In this case, by setting the pushing block 107 as the melt disconnecting component for disconnecting the second melt, in order to better disconnect the second melt, a guiding block is arranged below the pushing block 107, and the second melt is clamped between the pushing block 107 and the guiding block. The pushing block 107 and the guiding block are combined as the melt disconnecting component for disconnecting the second melt.

[0090] In the above embodiment or some other embodiments, a second excitation source may be added. The second excitation source is connected in series with an external trigger circuit, receives an external trigger signal to trigger, and drives the displacement of the cutting device. The first excitation source and the second excitation source are backup to each other. When one of the excitation sources fails to trigger an action, the other excitation source triggers an action, which can ensure excitation triggering, improve the breaking reliability, and enable the fuse product to be applicable to breaking in various situations.

[0091] By connecting a switching element in series in the parallel branch of the first excitation source and the parallel branch of the second melt, the reliability in the normal working state is improved, and the possibility of the first excitation source being accidentally triggered is avoided.

[0092] In order to solve the problem that when an abnormal situation occurs, the first melt cannot fuse to trigger the action of the first excitation source. In other embodiments, the first excitation source can also be connected in series with an external trigger circuit to receive an external trigger signal. When an overload or short-circuit current occurs, the first excitation source is triggered by the melting of the first melt. When an abnormal situation occurs, an external control system directly sends a trigger signal to the first excitation source through the external trigger circuit to make it act.

[0093] In order to solve the situation that the first excitation source fails and cannot act, a second excitation source can also be set as a backup for the first excitation source. The second excitation source can be connected to a trigger circuit controlled by a client control system outside the fuse. When an overload, short-circuit current or abnormal situation occurs, if the client control system determines that the fuse does not act within a certain period of time, it is determined that the first excitation source does not act. Then the client control system controls the external trigger circuit to send a trigger signal to the second excitation source. After the second excitation source acts and drives the cutting device to cut off the electrical circuit where the first conductive member and the second conductive member are located, the second melt is then cut off to achieve the protection of the main circuit.

[0094] In order to solve the problem that when an abnormal situation occurs, the first melt cannot fuse to trigger the action of the first excitation source. In some embodiments, it further includes a second excitation source and a melt disconnecting component; the melt disconnecting component is arranged corresponding to the first melt, and the second excitation source can be connected in series with an external trigger circuit; when an abnormal situation occurs, the second excitation source can act according to the received trigger signal, release the driving force, and drive the displacement of the melt disconnecting component. After the melt disconnecting component cuts off the first melt, the first excitation source triggers an action, drives the cutting device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then the melt disconnecting component continues to displace to disconnect the second melt.

Claims

1. A self-excited fuse, characterized in that, It includes a housing, terminal blocks, a first conductive member, a second conductive member, a first fuse element, a second fuse element, a first excitation source, and a cut-off device disposed in the housing; Both the first conductive member and the second conductive member are in a cylindrical structure, arranged in sequence along the axial direction of the cylindrical structure and disposed in the housing. One adjacent end of the first conductive member and the second conductive member is connected in series through the first fuse element; both the first excitation source and the cut-off device are located in the cylindrical structure of the first conductive member; the terminal blocks at both ends of the housing are electrically connected to the first conductive member and the second conductive member respectively, and the terminal blocks are fixedly arranged at both ends of the housing; The first excitation source and the second fuse element are respectively connected in parallel across both ends of the first fuse element, forming a first excitation source parallel branch and a second fuse element parallel branch; an arc extinguishing medium is filled around the second fuse element; During normal operation, current flows through the first conductive member, the first fuse element, and the second conductive member; When an overload current or a short-circuit current occurs, the first fuse element melts, and the voltage signal across the disconnected first fuse element serves as the trigger signal for the first excitation source. The first excitation source is triggered to act, releasing a driving force to drive the cut-off device to disconnect the electrical circuit where the first conductive member and the second conductive member are located. After that, the second fuse element melts or is disconnected by the cut-off device.

2. The self-actuating fuse according to claim 1, characterized in that, The first excitation source can also receive an external trigger signal. When an abnormal situation occurs, the first excitation source acts according to the received external trigger signal, releases a driving force, drives the cut-off device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then the second fuse element melts or is disconnected by the cut-off device; It further includes a second excitation source that can receive an external trigger signal; when the first excitation source fails, the second excitation source acts according to the received external trigger signal, releases a driving force to drive the cut-off device to disconnect the electrical circuit where the first conductive member and the second conductive member are located, and then disconnects the second fuse element.

3. The self-actuating fuse according to any one of claims 1 or 2, characterized in that, Switching elements are respectively connected in series on the first excitation source parallel branch and the second fuse element parallel branch; or, a switching element is connected in series on the first excitation source parallel branch or the second fuse element parallel branch; during normal operation, the switching element is not conducting; After the first fuse element melts, the switching element conducts, making the parallel branch where it is located conducting.

4. The self-actuating fuse according to claim 3, wherein The switching element is an electronic switching element. During normal operation, the electronic switching element is not conducting; when the first fuse element melts, the voltage across the first fuse element exceeds a set threshold, and the electronic switching element is triggered to conduct.

5. The self-actuating fuse according to claim 4, wherein The electronic switching element is a transient voltage suppression diode.

6. The self-actuating fuse according to claim 3, characterized in that The switching element connected in series on the second fuse element parallel branch is a mechanical switching element. In the normal operating state, the mechanical switching element is in an open state; when the first fuse element melts and the first excitation source acts to release a driving force, while the driving force drives the cut-off device to act, it can also drive the mechanical switching element to close, conducting the second fuse element parallel branch.

7. The self-actuating fuse according to claim 1, characterized in that, The connecting wire of the first excitation source parallel branch is located on the displacement path of the cutting device. When the cutting device cuts off the first conductive member and the second conductive member, the connecting wire of the first excitation source parallel branch can be cut off.

8. The self-actuating fuse according to any one of claims 1 or 2, characterized in that, On a part of the inner wall of the first conductive member and the second conductive member of the cylindrical structure in the circumferential direction, or on a part of the circumferential direction of the adjacent end portions, force-receiving surfaces are respectively formed extending towards each other along the radial direction of the cylindrical structure; the first fuse is connected in series between the force-receiving surfaces of the first conductive member and the second conductive member; the second fuse is located in the cylindrical structure of the second conductive member.

9. The self-actuating fuse according to claim 8, characterized in that, The force-receiving surfaces are respectively located at the ends of the adjacent ends of the first conductive member and the second conductive member, and the force-receiving surfaces of the first conductive member and the second conductive member are located in the same plane and are arranged in a staggered manner.

10. The self-actuating fuse according to claim 8, characterized in that, A first inner housing is fixedly connected in the first conductive member, and one end of the first inner housing is in contact and cooperation with the wiring terminal; a second inner housing is provided in the second conductive member, the first inner housing and the second inner housing are butted, and the force-receiving surfaces of the first conductive member and the second conductive member are clamped between the butted end faces of the first inner housing and the second inner housing, and the first fuse is located in the first inner housing and the second inner housing; the first excitation source and the cutting device are arranged in the first inner housing; The second fuse is located between the second inner housing and the second conductive member; when the first excitation source triggers an action, it drives the cutting device to displace along the first inner housing and the second inner housing, disconnecting the first conductive member and the second conductive member from the force-receiving surface; the second fuse melts or is disconnected by the cutting device.

11. The self-actuating fuse according to claim 10, characterized in that, The cutting device includes a first inner sleeve and a second inner sleeve connected in a butted manner. The first inner sleeve is located in the first inner housing, and the second inner sleeve is located in the second inner housing; a closed cavity is formed in the butted first inner sleeve and the second inner sleeve, and an arc extinguishing medium is filled in the first inner sleeve and the second inner sleeve; the force-receiving surfaces of the first conductive member and the second conductive member are clamped between the butted surfaces of the first inner sleeve and the second inner sleeve, or a part of the force-receiving surface of the first conductive member and a part of the first fuse or a part of the force-receiving surface of the second conductive member and a part of the first fuse are clamped between the butted surfaces of the first inner sleeve and the second inner sleeve, so that the narrow neck of the first fuse is located in the arc extinguishing medium in the first inner sleeve and the second inner sleeve; when the first excitation source triggers an action, it releases a driving force, driving the first inner sleeve and the second inner sleeve to displace relative to the first inner housing and the second inner housing, simultaneously disconnecting the first conductive member and the second conductive member, or simultaneously disconnecting the first fuse and the first conductive member or the second conductive member, and then the first inner sleeve and the second inner sleeve penetrate through the break between the first conductive member and the second conductive member.

12. The self-actuating fuse according to any one of claims 10 or 11, characterized in that, When one end of the second inner housing is open and the other end is closed, and the open end is docked with the first inner housing, the second melt is melted; when both ends of the second inner housing are through, a support guide cylinder is provided on the inner end face of the terminal block at the second conductive member, and the support guide cylinder is docked with the second inner housing to form a displacement channel, and the second melt passes through the docking surface between the support guide cylinder and the second inner housing; after the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, the second melt is disconnected.

13. The self-actuating fuse according to claim 12, characterized in that, It further includes a melt disconnection assembly; the melt disconnection assembly includes a push block and a guide block, the guide block is arranged at one end of the support guide cylinder facing the cutting device, one end of the push block is located in the second inner housing, and the other end is supported by the guide block; The second melt passes through the docking surface between the push block and the guide block and is clamped by the push block and the guide block; After the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, the cutting device drives the push block and the guide block to displace, thereby disconnecting the second melt.

14. The self-actuating fuse according to any one of claims 1 or 2, characterized in that, The positions corresponding to the first conductive member and the second conductive member of the cutting device are weak points for disconnection.

15. The self-actuating fuse according to any one of claims 1 or 2, characterized in that, The first melt is filled with an arc extinguishing medium around it.

16. The self-actuating fuse according to claim 10, characterized in that, A pressing piston is provided between the barrel wall of the first inner housing and the first conductive member, and the cavity where the pressing piston is located is communicated with the cavity where one end of the first excitation source releases driving force through an air passage; one end of the second melt is electrically connected to the second conductive member, and the other end passes through the first conductive member and is located on the displacement path of the pressing piston and is insulated from the first conductive member, so that the parallel branch of the second melt is not conducting; a support guide cylinder corresponding to the second inner housing is provided between the second inner housing and the terminal block, and one end of the second inner housing corresponding to the support guide cylinder is an open end, and the second melt passes through between the open end of the second inner housing and the support guide cylinder; When the first excitation source releases driving force, while the driving force drives the cutting device to displace, it also drives the pressing piston to displace. The pressing piston drives one end of the second melt located on the displacement path of the pressing piston to be electrically connected to the first conductive member, so that after the parallel branch of the second melt is conducting, the cutting device disconnects the electrical circuit where the first conductive member and the second conductive member are located, and then disconnects the second melt.

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