Activation protection for time-delay cutout fuse

Abstract

The application relates to the field of electric power control and electric vehicles, and discloses an excitation protection device for time-delay breaking of a fuse, which comprises an excitation source, an impact device and a conductor; further comprising a fuse, wherein an arc extinguishing chamber is arranged in the fuse, at least one fuse passes through the arc extinguishing chamber and is connected in parallel with the conductor; at least one breaking device is arranged on the fuse, one end of the breaking device extends out of the fuse and a displacement gap is reserved; after the excitation source drives the impact device to break the conductor, the fuse drives the breaking device to displace together to a stop displacement position of the breaking device, the fuse continues to displace, and the breaking device breaks the fuse. The excitation protection device can make the parallel fuses time-delay break and improve the breaking capacity of the excitation protection device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric power control and electric vehicles, and particularly relates to a protection device for circuit protection. BACKGROUND

[0002] Traditional circuit protection devices generally adopt thermal melt fuses, which have the following disadvantages: high power consumption (large heat generation), large volume and weight, limited current impact resistance, long breaking time, and uncontrolled breaking process. To solve the disadvantages of traditional thermal melt fuses, a structure for quickly cutting a conductor pre-break (i.e., an excitation fuse) has been developed and gradually expanded in application scope. The general structure of the excitation fuse includes an electronic ignition device (excitation source), a piston, a conductive busbar with a pre-break, and a shell. The working principle is as follows: the excitation fuse is connected in series in the circuit. When the vehicle is in a normal working state, the current flows through the conductor of the excitation fuse, and the product can be regarded as a conductor. When the vehicle is in an abnormal working state and needs to cut off the circuit, the vehicle sends a signal to trigger the excitation source, the excitation source drives the piston to move to cut off the conductor, and thus the circuit is disconnected.

[0003] Although this structure has improved the controlled breaking of the thermal melt fuse, it still has the following disadvantages: the air break itself has insufficient arc extinguishing capability, can only break smaller fault currents, and is difficult to break larger fault currents. The larger the arc current, the more difficult it is to extinguish; due to the limitations of the conductor structure and the movement space, it is difficult to design a larger break, and thus the single break has limited voltage resistance. In the case of low voltage (e.g., 500V), the single break can effectively break, but in the case of high voltage, the single break is obviously insufficient and difficult to effectively break.

[0004] Therefore, an integrated excitation fuse was developed, which consists of a fuse connected in parallel with the original excitation fuse. Its working principle is as follows: the vehicle sends a signal to trigger the excitation source, which pushes a piston to sequentially break the conductor and the arc-extinguishing fusible element, thus using the arc-extinguishing fusible element to extinguish the arc. There is a time difference between the piston breaking the conductor and the arc-extinguishing fusible element; therefore, this time can be used to reduce or interrupt the fault current through the arc-extinguishing medium, thereby improving breaking performance. However, due to the high speed of the piston, the actual time available for the arc-extinguishing medium to function is very short. In many cases, the arc-extinguishing medium cannot effectively play its role before the piston begins to cut off the melt, resulting in the following shortcomings: The piston speed is too fast, and the melt is not sufficiently current-limited or arc-extinguished. Therefore, the melt piston must cut off the circuit under a large fault current, making it difficult to disconnect or reducing the insulation performance after disconnection; When the melt piston cuts off a large current, the arc pressure at the melt break point rises rapidly, causing the product to crack; The main piston and the melt are difficult to match. The speed of the main piston may fluctuate greatly due to factors such as processing accuracy, fit tolerance, and differences in the energy of the excitation source. The melt design needs to meet various conditions, making the design difficult; The main piston usually moves to the bottom within hundreds of microseconds, making it difficult to achieve a large delay and preventing further increases in the upper limit of the breaking current. Summary of the Invention

[0005] The purpose of this invention is to provide an excitation protection device that can delay the disconnection of its parallel molten elements after the conductor is disconnected. By delaying the disconnection of the parallel molten elements, the segmentation capability and arc extinguishing capability are improved.

[0006] To achieve the above objectives, the present invention provides a time-delayed fusible link excitation and protection device, comprising an excitation source, an impact device, and a conductor; it also includes a fuse, wherein an arc-extinguishing chamber is provided inside the fuse, and at least one fusible link passes through the arc-extinguishing chamber and is connected in parallel with the conductor; at least one disconnecting device is provided on the fusible link, one end of the disconnecting device extending outside the fuse and retaining a displacement gap; when the excitation source drives the impact device to disconnect the conductor, it drives the fuse to move together with the disconnecting device until the disconnecting device stops moving, the fuse continues to move, and the disconnecting device disconnects the fusible link.

[0007] Preferably, when at least two disconnecting devices are provided at intervals on the melt, the displacement gaps of the disconnecting devices may be the same or different.

[0008] Preferably, the disconnecting device is clamped onto the melt.

[0009] Preferably, the fuse housing is provided with a cavity for accommodating the disconnecting device, and the fusible element passes through the fuse housing and the cavity.

[0010] Preferably, the arc-extinguishing chamber is provided in the fuse housing outside the cavity accommodating the disconnecting device.

[0011] Preferably, the housing of the fuse and the impact device are respectively provided with a limiting structure for defining the initial position.

[0012] Preferably, the connecting end of the fuse extends outside the fuse, and the fuse and the conductor remain in conductive connection when the fuse is displaced.

[0013] Preferably, the connecting end of the fuse is in a wave folding structure.

[0014] Preferably, the device further comprises an excitation protection device housing, the excitation source, the impact device and the fuse are respectively arranged in the excitation protection device housing; the conductor is arranged in the excitation protection device housing; a pressure relief air passage and a pressure relief cavity connected thereto are arranged on the excitation protection device housing; when in the initial position, the impact device closes the pressure relief air passage; when the impact device is displaced to disconnect the conductor, the pressure relief air passage is in communication with the cavities between the excitation source and the impact device.

[0015] Preferably, the impact device comprises a piston and a sleeve; the piston comprises a head and an impact portion, the sleeve closes the pressure relief air passage; the impact portion of the piston passes through the sleeve and leaves a gap therebetween; a displacement distance is left between the head of the piston and the sleeve; when the piston is displaced to disconnect the conductor, the head of the piston drives the sleeve to be synchronously displaced, the pressure relief air passage is in communication with the cavities between the excitation source and the head of the piston; the piston and the gas passing through the pressure relief air passage and the pressure relief cavity together drive the fuse to be displaced, or the gas passing through the pressure relief air passage and the pressure relief cavity alone drives the fuse to be displaced.

[0016] Preferably, when the gas passing through the pressure relief air passage and the pressure relief cavity alone drives the fuse to be displaced, the conductor limits the displacement of the head of the piston and the sleeve.

[0017] Preferably, at least one disconnection weak point is arranged on the conductor.

[0018] Preferably, when two disconnection weak points are arranged on the conductor at intervals, the impact end of the impact device is opposite to the disconnected portion of the conductor between the two disconnection weak points, and the impact end surface of the impact device matches the shape of the surface of the conductor opposite thereto.

[0019] Preferably, the excitation protection device housing comprises a first housing, a second housing, an upper cover and a bottom cover which are sealed by being spliced with each other; the conductor is arranged between the first housing and the second housing, the excitation source is arranged in the upper cover, the impact device is arranged in the first housing, the fuse is arranged in the second housing, and the bottom cover closes the second housing.

[0020] The excitation protection device of the application uses the impact device or gas to push the integrated fuse to move, because the mass of the fuse is larger, the acceleration and speed are smaller, and it needs longer time to move to the stop position, and the arc extinguishing fuse can work effectively in this time, so as to complete the current limiting and arc extinguishing of the fuse. When the fuse moves to the bottom, the breaking device breaks the fuse, and improves the post-breaking insulation capacity. The excitation fuse of the application increases the time of breaking the arc extinguishing fuse, so that the arc extinguishing fuse has sufficient time for current limiting and arc extinguishing, so that the working pressure of the main piston and the fuse piston is reduced, the breaking voltage and current are improved, and the post-breaking insulation performance of the product is also improved.

[0021] The specific advantages are:

[0022] 1) When the impact device is used to push the fuse to move downward, because the mass of the fuse is larger, the acceleration and speed generated under the same force condition are smaller than those of the scheme of breaking the fuse by other devices. The weight of the impact device is about several grams, and the weight of the integrated fuse is more than several tens of grams. In the same space size, the delay time generated is different by several times, so that the fuse has more working time for current limiting and arc extinguishing.

[0023] 2) The fuse has sufficient time to work, so that the fault current is rapidly reduced, and the breaking device on the fuse needs to break the low fault current, so that the breaking of the fault current is more easily completed.

[0024] 3) The space at the bottom of the fuse is large, and more breaking devices can be easily arranged, so that the breaking of larger fault current can be tolerated.

[0025] 4) The fuse is protected in the second shell and the bottom cover, and can be designed according to the fault tolerance. Even if the shell of the integrated fuse is slightly cracked and releases pressure due to excessive pressure during breaking, the product performance will not be affected or inconvenience will not be caused to the customer.

[0026] 5) Multiple sets of breaking devices can be arranged at different distances from the bottom cover and participate in breaking the fuse one by one, so as to further prolong the breaking time and reduce the overvoltage generated during breaking.

[0027] 6) After the impact device breaks the conductor, the pressure relief gas channel is used to reduce the pressure of the high-pressure gas and the driving force applied to the impact device, so as to reduce the movement speed of the impact device, further prolong the displacement time of the fuse and the breaking time of the fuse, and realize greater time delay effect. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of the excitation protection device in a normal working state.

[0029] Figure 2 This is a schematic diagram of the structure when the impact device disconnects the conductor but has not yet reached the fuse.

[0030] Figure 3 This is a schematic diagram of the structure when the impact device disconnects the conductive drive fuse and the disconnecting device (806, 808) contacts the bottom cover first.

[0031] Figure 4 This is a schematic diagram of the structure when the impact device disconnects the conductor, drives the fuse to shift relative to the disconnecting device (806, 808) to disconnect the molten metal, and the disconnecting device 807 contacts the bottom cover.

[0032] Figure 5 This is a schematic diagram showing the structure where the fuse contacts the bottom cover, and the disconnecting device is completely reversed to disconnect the fusible element.

[0033] Figure 6 This is a partial cross-sectional three-dimensional structural diagram of Example 2 under normal working conditions.

[0034] Figure 7 This is a schematic diagram of the three-dimensional structure of a partial cross-section from another angle under normal working conditions in Embodiment 2.

[0035] Figure 8 This is a schematic diagram of the structure under normal operating conditions in Example 2.

[0036] Figure 9 This is a schematic diagram of the structure of Example 2, showing the impact device reaching the conductor but not yet entering the sleeve.

[0037] Figure 10 This is a schematic diagram of the impact device in Example 2 disconnecting the conductor and partially entering the sleeve structure.

[0038] Figure 11 This is a schematic diagram of the structure of Example 2, showing the impact device disconnecting the conductor, the head of the impact device fully entering the sleeve, and the impact end of the impact device reaching the fuse cover.

[0039] Figure 12 This is a schematic diagram of the structure of Example 2, where the impact device drives the sleeve to drive the fuse to move, and the disconnecting device (806, 808) first contacts the bottom cover, the depressurization air passage and the cavity between the excitation source and the impact device are connected.

[0040] Figure 13 This is a schematic diagram of the structure of Example 2, where the impact device drives the sleeve to disconnect the conductor, and the fuse is driven to move relative to the disconnecting device (806, 808) to disconnect the molten material, and the disconnecting device 807 contacts the bottom cover.

[0041] Figure 14 This is a schematic diagram of the structure of Example 2, where the fuse contacts the bottom cover and the disconnecting device is completely reversed to disconnect the fusible element.

[0042] Figure 15 is a partial sectional perspective view of the embodiment 3 in normal working state.

[0043] Figure 16 is another partial sectional perspective view of the embodiment 3 in normal working state.

[0044] Figure 17 is a structural schematic diagram of the embodiment 3 in normal working state.

[0045] Figure 18 is a structural schematic diagram of the embodiment 3 in the process of the impact device breaking the conductor and the impact device head entering the sleeve.

[0046] Figure 19 is a structural schematic diagram of the embodiment 3 in the process of the impact device breaking the conductor, the impact device head completely entering the sleeve and driving the sleeve to move, the opening of the pressure relief gas channel being in communication with the cavity between the impact device and the excitation source, and the gas starting to drive the displacement of the fuse.

[0047] Figure 20 is a structural schematic diagram of the embodiment 3 in the process of the impact device driving the sleeve to the conductor, forming a motion dead point, the impact device impact end and the conductor broken part being above the fuse cover and not in contact with the fuse cover, and the opening of the pressure relief gas channel being completely opened, the gas driving the fuse to move, and the breaking device (806, 808) first contacting the bottom cover.

[0048] Figure 21 is a structural schematic diagram of the embodiment 3 in the process of the gas driving the fuse to move and break the fuse, and the breaking device 807 contacting the bottom cover.

[0049] Figure 22 is a structural schematic diagram of the embodiment 3 in the process of the fuse contacting the bottom cover and the breaking device being completely reversed to break the fuse.

[0050] Upper cover 10, limiting structure 101, first shell 20, second shell 30, pressure relief cavity 301, bottom cover 40, buffer pad 401, conductor 50, conductor breaking part 502, excitation source 60, impact device 70, piston head 701, piston impact part 702, limiting protrusion 703, sealing ring 704, sleeve 710, fuse cover 801, fuse bottom shell 802, fuse 803, arc extinguishing chamber 805, breaking device 806, breaking device 807, breaking device 808, pressure relief gas channel 90 DETAILED DESCRIPTION

[0051] For the above technical solution, a preferred embodiment is described in detail in combination with the drawings.

[0052] The excitation protection device of the application comprises a shell, an excitation source, an impact device, a conductor and a fuse. The fuse body is provided with at least one disconnecting device which extends outside the fuse shell and has a movement gap with the inner wall of the shell of the excitation protection device. The fuse is connected in parallel with the conductor. After the excitation source receives an excitation signal and drives the impact device to displace and disconnect the conductor, the impact device drives the fuse to move. When the disconnecting device on the fuse contacts the inner wall of the shell of the excitation protection device, the movement of the fuse is stopped, and the fuse body with the fuse body continues to move, so that the disconnecting device disconnects the fuse body. The shell of the excitation protection device, the impact device, the shell of the fuse and the disconnecting device are all made of insulating materials.

[0053] In the above technical solution, the preferred embodiments are described in detail in combination with the drawings.

[0054] Embodiment 1

[0055] The shell of the excitation protection device, as shown in Figure 1 , comprises a first shell 20 and a second shell 30 which are sealed and connected. A conductor 50 is arranged between the first shell 20 and the second shell 30. Connection ends are arranged outside the shells respectively. The two ends of the conductor 50 are connected with the connection ends respectively in an integrated connection, a welding connection or other conductive connection mode. A sealing device is arranged between the first shell and the second shell and the conductor for sealing the contact surface. In this embodiment, the sealing device is a sealing ring. An upper cover 10 is arranged on the first shell 20, and a bottom cover 40 is arranged at the bottom of the second shell 30.

[0056] The upper cover 10 and the first shell 20 are provided with limiting structures 101 which are clamped with each other for limiting at the contact surface. The limiting structures are convex edges and grooves which are nested with each other. The convex edges and the grooves are provided with sealing rings for sealing the contact surface. Through cavities are formed in the upper cover 10, the first shell 20 and the second shell 30 respectively.

[0057] An excitation source 60 is arranged in the cavity of the upper cover 10. The excitation source 60 is provided with a sealing device for sealing the contact surface between the excitation source 60 and the upper cover 10, so as to prevent the high-pressure gas released after the excitation source 60 is actuated from leaking out of the contact surface. One end of the trigger connector of the excitation source 60 is located outside the shell and can be connected with the excitation signal sending end. The excitation source 60 can be arranged in the upper cover by injection molding. The excitation source 60 is a micro gas generating device. When it receives an excitation signal, it ignites and releases high-pressure gas, thereby providing driving force for the impact device.

[0058] The cavity opening end of the first shell 20 at the joint with the upper cover 10 is in a trumpet shape and forms a wedge-shaped gap with one end of the adjacent upper cover 10.

[0059] The impact device 70 is arranged in the cavity of the first housing 20. The impact device 70 is a piston structure. It includes a piston head 701 and a piston impact part 702. The piston head 701 can be arranged in the cavity of the first housing 20 by interference fit, limiting structure, etc., to maintain the initial position of the piston 70. In this embodiment, it is achieved by limiting structure, specifically, a limiting convex ridge 703 with a relatively wedge-shaped gap is arranged on one end of the piston head, and the limiting convex ridge 703 of the piston head is clamped in the wedge-shaped gap at the end of the first housing connected with the upper cover to form a limiting structure, which ensures the initial position of the piston. When the piston is displaced, the limiting of the limiting convex ridge 703 can be overcome.

[0060] The contact surface between the piston head and the cavity of the first housing is sealed by a sealing ring 704 to prevent high-pressure gas released by the excitation source from leaking between the contact surface of the piston and the first housing, thereby reducing the driving force. The contact surface between the piston head and the cavity of the first housing can also be sealed by interference fit, or the contact surface between the piston head and the cavity of the first housing can be tightly fitted to achieve sealing.

[0061] A groove is arranged on the end face of the piston head 701 for the high-pressure gas released by the excitation source to act on the groove.

[0062] A U-shaped groove structure is arranged on the end face of the piston impact part 702 as an impact end of the disconnected conductor, and the width of the U-shaped groove structure corresponds to the disconnected part 502 of the conductor. The length of the U-shaped groove structure is consistent with the width of the conductor, and the side edge angle of the end face of the piston impact part 702 is located in front of the U-shaped groove structure and outside the conductor, forming a containing cavity. When the piston impact part 702 disconnects the conductor, the disconnected part 502 of the conductor is partially contained in the U-shaped groove structure and fully contained in the end of the piston impact part 702.

[0063] The conductor 50 is a long strip-shaped structure, which passes through the cavities of the first and second housings. The two ends of the conductor 50 are located outside the housings as connecting ends. The conductor 50 is in sealed contact with the contact surfaces of the first and second housings, which can be sealed by a sealing ring. The conductor 50 located in the cavities of the first and second housings is provided with a breaking weak point 501. The breaking weak point is used to reduce the mechanical strength of the conductor. In this embodiment, the breaking weak point is a V-shaped groove penetrating the width of the conductor. The two side edges of the U-shaped groove structure of the end surface of the piston impact portion 702 protrude correspondingly to the breaking weak points of the conductor, so as to break the conductor from the breaking weak points. Meanwhile, the U-shaped groove shape of the piston impact portion 702 matches the shape of the conductor portion between the two breaking weak points on the opposite conductor surface. After the conductor is broken by the piston impact portion, the broken conductor portion can be accommodated in the groove of the end surface of the piston impact portion 702, so that the piston drives the broken conductor portion to move together to facilitate the driving of the fuse. The end surface of the piston impact portion is provided with a groove to drive the broken conductor portion to move together, so that the fuse has a large force receiving area, the forces at each force receiving point are balanced, and the fuse moves more stably.

[0064] Of course, the end surface of the piston impact portion can also not be provided with a groove structure. The piston impact portion is opposite to the conductor portion between the two breaking weak points, so as to break the conductor from the breaking weak points, and then the piston drives the broken conductor portion to drive the fuse.

[0065] When the conductor is broken as shown in Figure 1 When two breaking weak points are provided, the cavity area of the second housing near the conductor is consistent with or slightly larger than the conductor area between the two breaking weak points and the cross-sectional area of the piston impact portion, so as to ensure that the arc generated by the broken conductor portion is squeezed in the cavity of the second housing, thereby facilitating arc extinguishing.

[0066] The fuse is arranged in the cavity of the second housing and located in front of the movement of the impact device and the broken conductor portion. The fuse includes a bottom shell 802 and a cover 801 covering the bottom shell. A plurality of grooves are respectively arranged on the abutting surfaces of the cover 801 and the bottom shell 802. When the cover and the bottom shell are spliced to form a fuse housing, the grooves on the cover 801 and the bottom shell 802 are respectively abutted to form a plurality of arc extinguishing chambers 805, which are filled with arc extinguishing medium. At least one cavity is arranged in the fuse housing. In this embodiment, three cavities are arranged. The fuse body 803 is arranged between the contact surfaces of the bottom shell 802 and the cover 801 and is fixed by the contact pressure of the cover and the bottom shell. The contact surfaces of the cover and the bottom shell located on both sides of the cavity are provided with inclined surface structures, and the contact surfaces of the cover and the bottom shell located on both sides of the cavity are provided with an eight-shaped structure.

[0067] The surface of the fuse cover 801 on the side of the conductor 50 is provided with a groove structure. When the impact device disconnects the conductor, the impact end surface enters the groove structure to drive the displacement of the fuse. The groove structure is provided on the cover, which can extend the displacement distance of the impact device, make the structure of the excitation protection device more compact, and smaller in size.

[0068] The melt 803 is connected to the conductor at both ends after passing through the arc extinguishing chamber and the cavity, so that the fuse is connected in parallel with the conductor. A notch is formed on the cover 801 near the surface where the melt is connected to the conductor. The melt is folded in a wave shape at the notch and is connected to the conductor in an electrically conductive manner. In this way, when the fuse moves, the end of the melt connected to the conductor can always remain in the connection device and will not be pulled off from the connection end. The melt 803 at the three cavities is provided with a disconnecting device (806, 807, 808) respectively. The disconnecting device is located in front of the displacement of the impact device and the conductor. The resistance of the melt 803 is much larger than the resistance of the conductor. In the normal working state, the current flows through the conductor, and only a small current can flow through the melt 803.

[0069] The melt 803 is arranged in the disconnecting device. For example, a groove is formed on one side of the disconnecting device, and the melt is arranged in the groove. Alternatively, the disconnecting device is composed of two parts that are clamped together, and the melt is clamped between the clamped parts. One end of the disconnecting device protrudes outside the fuse shell and leaves a gap with the bottom cover 40, and the other end also leaves a movement gap in the cavity. An insulating buffer pad 401 is arranged on the bottom cover 40. The buffer pad can fully absorb the impact force generated by the fuse, thereby avoiding deformation of the bottom protective cover.

[0070] The distance between the end of the disconnecting device protruding out of the shell and the bottom cover can be the same or different. In this embodiment, the distances between the disconnecting devices (806, 808) and the bottom cover are the same, and the distance between the disconnecting device 807 and the bottom cover is greater than the distances between the disconnecting devices (806, 808) and the bottom cover.

[0071] A limiting structure is arranged between the fuse and the second shell to limit the initial position of the fuse. The limiting structure can be a limiting rib arranged on the second shell, and a limiting step arranged outside the cover or the bottom shell of the fuse is clamped on the limiting rib to limit the position. Alternatively, a limiting groove is arranged on the second shell, and a limiting protrusion is arranged outside the shell of the fuse, and the limiting protrusion is clamped in the limiting groove to limit the position.

[0072] Regardless of the initial position limitation of the impact device or the initial position limitation of the fuse, the limiting structure can be other than the structure described in this embodiment.

[0073] Working process

[0074] Figure 1 For the normal working state of the excitation protection device.

[0075] When the fault occurs, the excitation source receives the excitation signal action, releases high-pressure gas, the high-pressure gas drives the impact device to move to overcome the limit structure, disconnects the conductor, and the reference Figure 2 The impact device drives the conductor disconnecting part 502 to continue to displace into the second shell cavity, and performs arc extinguishing through extrusion between the contact surface of the second shell;

[0076] Referring to Figure 3 The impact device drives the fuse to displace to overcome the limit structure, drives the disconnecting device to displace to the bottom cover, and the disconnecting device (806, 808) first contacts the bottom cover 40 and stops displacement under the driving of the impact device, and the disconnecting device 807 continues to displace with the fuse and does not contact the bottom cover.

[0077] Referring to Figure 4 Under the continuous driving of the impact device, the fuse displaces relative to the disconnecting device (806, 808), the disconnecting device (806, 808) disconnects the fuse, and two breaks are formed on the fuse. At this time, the disconnecting device 807 contacts the bottom cover and stops displacement.

[0078] Referring to Figure 5 The impact device continues to drive the fuse to displace relative to the disconnecting device 807, the disconnecting device 807 disconnects the fuse, a third break is formed on the fuse, and the circuit is completely disconnected. At this time, the bottom shell of the fuse contacts the buffer pad at the bottom cover, and the impact device also displaces to the dead point.

[0079] The disconnecting device disconnects the fuse in sequence, and multiple breaks are formed on the fuse, which can avoid cutting off the fuse at the same time, and is beneficial to reduce the overvoltage generated when the fault current is disconnected.

[0080] Working principle

[0081] When the fault current is generated, the impact device disconnects the conductor to form a break. Since the fuse is connected in parallel, most of the fault current flows through the fuse on the fuse, and the arc generated at the break of the conductor is small and can be extinguished through air; with the displacement of the impact device, the fuse is first driven to move, and during the movement of the fuse, the fuse is not cut off. Only when the disconnecting device displaces to contact the bottom cover and stops displacement, and the fuse displaces relative to the disconnecting device, can the fuse be cut off. The displacement distance is increased by the displacement of the fuse and the disconnecting device together and the displacement of the fuse relative to the disconnecting device, the fuse is disconnected in time, and the time for the arc-extinguishing medium to participate in arc extinguishing is lengthened. At least one break is formed on the fuse, and good arc extinguishing is achieved through the arc-extinguishing medium.

[0082] Embodiment 2

[0083] Referring to Figure 6 to Figure 7A pressure relief air passage 90 is formed in the first housing 20, and the pressure relief air passage 90 is in communication with a pressure relief cavity 301 formed in the second housing 30. The pressure relief air passage 90 is in communication with a cavity between the cover and the conductor of the fuse. The opening of the pressure relief air passage 90 is located at the cavity of the first housing. Referring to Figure 8 A sleeve 710 is arranged in the cavity of the first housing 20 to close the opening of the pressure relief air passage 90 (not shown). The sleeve 710 is a hollow ring structure, and the piston head is kept a distance away from the sleeve 710. The piston impact portion 702 is located on the side of the conductor 50 through the hollow portion of the sleeve 710. The initial position of the sleeve 710 is limited by a limiting structure, such as a protrusion and groove structure, a protrusion and step structure, an interference fit structure, etc.

[0084] Workflow:

[0085] Figure 8 Structure diagram of the protection device in a normal working state;

[0086] When a fault occurs, referring to Figure 9 The excitation source receives the excitation signal and acts to release high-pressure gas, drive the impact device 70 to overcome the limiting structure, and displace the impact end of the impact device 70 to the conductor 50. The impact device 70 and the sleeve 710 are in a state of being ready to contact;

[0087] Referring to Figure 10 The impact device 70 continues to displace to disconnect the conductor 50, so that the conductor disconnection portion 502 is accommodated in the accommodation cavity at the end surface of the impact device 70, and the head of the impact device 70 enters the sleeve 70;

[0088] Referring to Figure 11 The impact device 70 continues to displace to above the cover of the fuse. At this time, the impact device 70 completely enters the sleeve, the sealing ring arranged outside the impact device 70 is in close contact with the inner wall of the sleeve, and the sleeve 710 drives the sleeve to overcome the limiting structure of the sleeve;

[0089] Referring to Figure 12 The impact device 70 drives the sleeve 710 to continue to displace and drive the fuse to displace. At this time, the opening of the pressure relief air passage 90 is in communication with the first housing cavity where the high-pressure gas released by the excitation source is located. The high-pressure gas enters the pressure relief cavity through the pressure relief air passage 90, so that the pressure of the high-pressure gas is reduced, and thus the driving force of the high-pressure gas is reduced. At the same time, the gas entering the side of the cover of the fuse also provides a reverse force to the impact device, so as to slow down the displacement rate of the impact device. The fuse displaces under the combined action of the impact device with a reduced speed and the gas. Compared with the first embodiment, the disconnection device (806, 808) of the fuse is in contact with the buffer pad at the bottom cover 40 for a longer period of time;

[0090] Referring to Figure 13, the impact device 70 drives the sleeve 710 to continue to drive the fuse relative to the breaking device (806, 808) displacement, the breaking device (806, 808) breaks the fuse, forming two breaks on the fuse; at the same time, the breaking device 807 is in contact with the buffer pad at the bottom cover;

[0091] Referring to Figure 14 , the impact device 70 drives the sleeve 710 to continue to drive the fuse relative to the breaking device (806, 807, 808) displacement, the breaking device 807 breaks the fuse, forming a third break on the fuse. At this time, the fuse bottom shell is in contact with the buffer pad at the bottom cover, and the impact device is also displaced to the dead point.

[0092] Example 3

[0093] Referring to Figure 15 to Figure 17 , the structure diagram of the normal state of example 3. Compared with example 2, the impact part of the impact device 70 is relatively short, and in the normal state, the sleeve 710 closes the opening of the pressure relief air duct 90.

[0094] When the impact device 70 breaks the conductor 50 and drives the sleeve to move to the conductor, the conductor limits the sleeve and the impact device, and the impact device stops moving. When the pressure relief air duct 90 is displaced, it begins to communicate with the cavity between the impact device and the excitation source, and the gas gradually enters the cavity between the fuse cover and the conductor. The gas driven by the reduced pressure drives the fuse to displace to achieve fuse breaking. Example 3 has the best delay effect compared with example 1 and example 2.

[0095] Workflow:

[0096] Figure 15 to Figure 17 The structure diagram of the normal state of the excitation protection device;

[0097] When a fault occurs, referring to Figure 18 , the excitation source receives the excitation signal and acts to release high-pressure gas, drive the impact device 70 to overcome the limiting structure, break the conductor 50, and the impact device 70 and the sleeve 710 are in contact with each other. The opening of the pressure relief air duct 90 is still closed by the sleeve 710;

[0098] Referring to Figure 19 , the impact device 70 continues to displace, the head of the impact device 70 enters the sleeve to overcome the sleeve limiting structure and drive the sleeve to displace, the opening of the pressure relief air duct 90 communicates with the cavity between the impact device and the excitation source, and the gas enters the pressure relief cavity 301 through the pressure relief air duct 90. The gas after pressure reduction begins to slowly drive the fuse to displace;

[0099] Referring to Figure 20, the impact device 70 drives the sleeve to continue displacement to the conductor, the conductor limits the position of the impact device and the sleeve, the impact device and the sleeve stop displacement, the impact end of the impact device and the broken part of the conductor are above the fuse cover, and the impact end is not in contact with the fuse cover; the opening of the pressure relief air channel 90 is fully opened, a large amount of gas enters the pressure relief cavity, drives the fuse to displace, and the disconnecting device (806, 808) is in contact with the bottom cover;

[0100] Referring to Figure 21 , the gas continues to drive the fuse to displace relative to the disconnecting device (806, 808), the disconnecting device (806, 808) disconnects the fuse, and two broken parts are formed on the fuse; at the same time, the disconnecting device 807 is in contact with the buffer pad at the bottom cover.

[0101] Referring to Figure 22 , the gas continues to drive the fuse to displace relative to the disconnecting device (806, 807, 808), the disconnecting device 807 disconnects the fuse, and a third broken part is formed on the fuse. At this time, the fuse bottom shell is in contact with the buffer pad at the bottom cover.

[0102] Compared with the above three embodiments, in the embodiment 1, the conductor is disconnected by the impact device, and then the fuse is driven to displace, the fuse is disconnected in sequence, and the delay time is relatively short; in the embodiment 2, the fuse is driven to displace by the impact device and the gas, but the driving force of the gas after pressure reduction is reduced, and the impact device is subjected to a reverse force, so that the movement speed of the impact device is reduced, the delay time of the embodiment 2 is longer than that of the embodiment 1, and the delay effect is better; in the embodiment 3, the conductor is disconnected by the impact device, and the fuse is driven to displace by the gas after pressure reduction, the driving force of the gas after pressure reduction is reduced, the displacement speed of the fuse is slow, and the delay time of the embodiment 3 is the longest and the delay effect is the best compared with the embodiment 1 and the embodiment 2.

Claims

1. An activation protection device for a time delay cutout fuse comprising an activation source, an impact device, a conductor; characterized in that, The fuse further comprises an arc-extinguishing chamber, at least one fuse element passing through the arc-extinguishing chamber in parallel with the conductor, and the end of the fuse element connected with the conductor being in a folded structure; at least one disconnecting device is arranged on the fuse element, and one end of the disconnecting device extends out of the fuse with a displacement gap; after the impact device is driven by the excitation source to disconnect the conductor, the fuse is driven to displace synchronously with the disconnecting device until the at least one disconnecting device stops displacing, and the fuse element remains in a conducting state during the synchronous displacement of the fuse and the disconnecting device; then the fuse relatively displaces with respect to the at least one disconnecting device to disconnect the fuse element.

2. The energization protection device according to claim 1, characterized in that, When at least two disconnecting devices are arranged on the fuse element at intervals, the displacement gaps of the disconnecting devices are the same or different.

3. The energization protection device according to claim 1, characterized by The disconnecting device is clamped on the fuse element.

4. The energization protection device according to claim 1, characterized by A cavity accommodating the disconnecting device is arranged on the shell of the fuse, and the fuse element passes through the shell and the cavity of the fuse.

5. The energization protection device according to claim 4, characterized in that, The arc-extinguishing chamber is arranged in the shell of the fuse outside the cavity accommodating the disconnecting device.

6. The energization protection device according to claim 1, characterized by Limiting structures defining initial positions are respectively arranged on the shell of the fuse and the impact device.

7. The energization protection device according to claim 1, characterized by The end of the fuse element connected with the conductor extends out of the fuse, and the fuse element remains in a conducting connection with the conductor when the fuse displaces.

8. The energization protection device according to claim 7, characterized in that The end of the fuse element connected with the conductor is in a wavy folded structure.

9. The energization protection device according to claim 1, characterized by The excitation protection device further comprises a shell, and the excitation source, the impact device and the fuse are arranged in the shell; the conductor passes through the shell; a pressure relief air channel and a pressure relief cavity connected with the pressure relief air channel are arranged on the shell; when in an initial position, the impact device closes the pressure relief air channel; after the impact device displaces to disconnect the conductor, the pressure relief air channel is in communication with the cavity between the excitation source and the impact device.

10. The energization protection device according to claim 9, characterized in that, The impact device comprises a piston and a sleeve; the piston comprises a head and an impact portion, and the sleeve closes the pressure relief air channel; the impact portion of the piston passes through the sleeve with a gap; a displacement distance is reserved between the head of the piston and the sleeve; after the piston displaces to disconnect the conductor, the head of the piston drives the sleeve to displace synchronously, and the pressure relief air channel is in communication with the cavity between the excitation source and the head of the piston; the piston and the gas passing through the pressure relief air channel and the pressure relief cavity together drive the fuse to displace, or the gas passing through the pressure relief air channel and the pressure relief cavity alone drives the fuse to displace.

11. The energization protection device according to claim 10, characterized in that When the gas passing through the pressure relief air channel and the pressure relief cavity alone drives the fuse to displace, the conductor limits the displacement of the head of the piston and the sleeve.

12. The energization protection device of claim 1, wherein At least one disconnecting weak point is arranged on the conductor.

13. The energization protection device according to claim 12, characterized in that When two disconnecting weak points are arranged on the conductor at intervals, the impact end of the impact device is opposite to the disconnected portion of the conductor between the two disconnecting weak points, and the shape of the impact end surface of the impact device matches the shape of the surface of the conductor opposite to the impact end.

14. The energization protection device according to any one of claims 1 to 13, characterized by The excitation protection device housing comprises a first housing, a second housing, an upper cover and a bottom cover which are sealed by splicing with each other; the conductor is arranged between the first housing and the second housing, the excitation source is arranged in the upper cover, the impact device is arranged in the first housing, the fuse is arranged in the second housing, and the bottom cover seals the second housing.

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