A motor domain protection fuse

Abstract

A motor domain protection fuse includes a shell, an electronic ignition tube, a piston, a first conductive row, a second conductive row and a third conductive row, and a fuse body. A channel is arranged in the shell for displacement of the piston. The piston is arranged in the channel. The first conductive row, the second conductive row and the third conductive row are arranged in the shell in a staggered manner. The first conductive row, the second conductive row and the third conductive row have pre-break points which pass through the channel where the piston is arranged and are located on the displacement path of the piston. The first conductive row, the second conductive row and the third conductive row have the fuse bodies connected in parallel, respectively. Cavities corresponding to the fuse bodies are arranged in the shell outside the channel where the piston is arranged. The fuse bodies are arranged in the corresponding cavities. The electronic ignition tube is arranged on the shell. High-pressure gas released by the electronic ignition tube drives the piston to displace, simultaneously disconnecting the first conductive row, the second conductive row and the third conductive row, and the fuse bodies are fused. The fuse structure is compact and suitable for the motor domain.

Description

Technical Field

[0001] This invention relates to the fields of power control and electric vehicles, and in particular to protective fuses for motors with complex internal structures in multiphase circuits and products that require current interruption. Background Technology

[0002] Currently, a relatively mature excitation fuse product already exists on the market. It has a structure that sequentially cuts off the conductor bus and the fusible element. Its general structural composition includes: a housing, on which an electronic ignition device, piston, conductor bus, fuse structure, fusible element cutter push plate, and fusible element cutter assembly are arranged sequentially from bottom to top. The fuse structure includes the fuse housing, the fusible element, and the arc-extinguishing medium. The fusible element passes through the fuse housing, and the arc-extinguishing medium fills the fuse housing. The fusible element is connected in parallel with the conductor bus. The fusible element cutter assembly is set in the displacement channel of the fuse structure. The fusible element is located on the displacement path of the fusible element cutter assembly. The fusible element cutter push plate is located between the piston and the fusible element cutter assembly and is supported by the fusible element cutter assembly.

[0003] The working principle of this type of excitation fuse:

[0004] When the excitation fuse is connected in series in the circuit, under normal current conditions, the power flows through the busbar. Since the resistance of the fuse element is much greater than that of the busbar, the current flowing through the fuse element is negligible. At this time, the excitation fuse is equivalent to a conductor.

[0005] When an abnormal situation occurs (such as a new energy vehicle operating abnormally or a collision), requiring circuit disconnection, the external control system (such as the vehicle control system outside the fuse product) sends a trigger signal (electrical signal) to the electronic ignition assembly. The electronic ignition assembly triggers and releases high-pressure gas as a driving force, driving the piston to move. Through the displaced piston, the conductive busbar is cut off, forming a physical port, and current flows through the fusible element. Then, the piston continues to move, pushing the fusible element cutter pusher plate to move. The fusible element cutter pusher plate pushes the fusible element cutter assembly to move, breaking the fusible element and completely disconnecting the circuit. The fusible element fracture point is located in the arc-extinguishing medium within the fuse housing, where the arc is extinguished.

[0006] Although this type of excitation fuse has significantly improved performance compared to thermal fuses, it also has the following shortcomings:

[0007] 1. Due to the large size of existing excitation fuses and the fact that most of the conductors are single-circuit copper busbars, they cannot adapt to some more complex circuit situations.

[0008] 2. This type of excitation fuse structure is mostly used in single DC or single AC applications, and cannot achieve simultaneous disconnection of the DC terminal of the IGBT in the motor domain and the AC terminal of the motor. Summary of the Invention

[0009] The purpose of this invention is to make more rational use of the internal space of the excitation fuse by arranging three conductive busbars, so that the three conductive busbars are respectively connected to the DC terminal of the IGBT in the motor domain and the AC terminal of the motor, integrating the ability to interrupt DC and AC simultaneously into the same product, thus making it more suitable for use in compact equipment and protecting the current flow of the entire motor domain.

[0010] To address the aforementioned objectives, this invention provides a motor domain protection fuse, comprising a housing, an electronic ignition tube, a piston, a first conductive busbar, a second conductive busbar, a third conductive busbar, and a fusible element. A channel for piston displacement is provided within the housing, and the piston is positioned within this channel. The first, second, and third conductive busbars are staggered and pass through the housing at varying heights. Pre-break points of the first, second, and third conductive busbars pass through the channel containing the piston and are located along the piston's displacement path. The fusible element is connected in parallel to each of the first, second, and third conductive busbars. Cavities corresponding to the fusible elements are provided in the housing outside the channel containing the piston, and the fusible elements pass through these corresponding cavities. The electronic ignition tube is mounted on the housing. High-pressure gas released by the electronic ignition tube drives the piston to move, simultaneously disconnecting the first, second, and third conductive busbars, causing the fusible element to melt.

[0011] Preferably, the pre-break points of the first, second, and third conductive busbars are staggered in height, and the piston has three impact ends arranged in a stepped manner, with each impact end corresponding to one conductive busbar; the three impact ends of the piston have the same stroke distance from the pre-break point of the corresponding conductive busbar.

[0012] Preferably, the first and second conductive busbars are located on opposite sides of the housing, and the third conductive busbar is located in the middle of the housing.

[0013] Preferably, the cavities through which the melt passes are distributed in the upper and lower parts of the shell outside the piston displacement channel; the cavities are filled with an arc-extinguishing medium.

[0014] Preferably, the cavity located in the upper part of the housing is formed by a groove opened on the housing and a melt cap disposed on the groove, and the cavity located in the lower part of the housing is formed by a groove opened on the housing and a bottom plate.

[0015] Preferably, cavities are respectively provided on the upper part of the housing and on opposite sides of the piston displacement channel; the melt connected in parallel on the first conductive busbar and the second conductive busbar are respectively disposed in the corresponding cavities on the upper part of the housing, the shape of the melt matches the shape of the cavity, and a support structure is provided at the bottom of the cavity to support the melt and position the melt.

[0016] Preferably, the fusible element connected in parallel on the third conductive busbar is disposed in the cavity at the lower part of the housing, and a fuse structure is disposed in the cavity. The base plate provides support and fixation for the fuse structure. The fuse structure is filled with an arc-extinguishing medium, and the fusible element connected in parallel on the third conductive busbar passes through the arc-extinguishing medium in the fuse structure.

[0017] Preferably, the fuse structure is provided with a melt cutter displacement channel along the piston displacement direction, and a melt cutter assembly is provided in the melt cutter displacement channel. The melt passes through the melt cutter displacement channel and is located on the displacement path of the melt cutter assembly. The melt cutter assembly protrudes from the fuse structure towards the piston, and a piston pusher plate is provided at the end of the melt cutter assembly that protrudes from the fuse structure. The piston pusher plate is located on the piston displacement path. When the piston cuts the conductive busbar, the piston pushes the piston pusher plate and the melt cutter assembly to break the melt connected in parallel to the third conductive busbar.

[0018] Preferably, the fuse structure includes a fuse housing and a fuse cover, with mating protrusions at corresponding positions in the middle of the fuse cover and the fuse housing; the fusible element passes through the cavity formed by the fuse housing and the fuse cover, and is held between the protrusions of the fuse cover and the fuse housing; the cavity formed by the fuse housing and the fuse cover is filled with an arc-extinguishing medium, which is located outside the fusible element cutter displacement channel.

[0019] Preferably, the housing is an insulated and sealed housing.

[0020] Preferably, an inter-electrode insulating element is provided between each of the conductive bars, and the inter-electrode insulating element is located outside the piston displacement channel.

[0021] Preferably, the first conductive busbar and the second conductive busbar are arranged parallel to each other in the horizontal direction and spaced apart. The third conductive busbar is arranged parallel to and opposite to the first conductive busbar and the second conductive busbar in the vertical direction. At least one side of the first conductive busbar, the second conductive busbar and the third conductive busbar located in the piston displacement channel is provided with a notch to form the pre-break. The pre-breaks of the first conductive busbar, the second conductive busbar and the third conductive busbar are arranged with their heights staggered.

[0022] Preferably, the first and second conductors are configured for three-phase AC power in the motor domain, and the third conductor is configured for DC power in the IGBT module of the motor domain.

[0023] The advantages of this invention are:

[0024] The product is designed with three-way current protection, which solves the problem of simultaneous protection of AC and DC power in the motor domain, greatly reducing the space and cost of motor domain usage.

[0025] The fusible element is assembled in the upper and lower parts of the fuse housing, making full use of the existing unused space in the housing, improving the space utilization rate of the housing, making the excitation fuse structure compact and convenient, and saving cumbersome installation steps.

[0026] Because of its compact design, this circuit can be designed as a three-way disconnection structure in a small space. It is suitable for the protection of multi-phase circuits and avoids circuit interference and failure caused by the blown single-phase fuse.

[0027] The three conductive busbars are staggered in height to further reduce the space required.

[0028] Current flows through both ends of the busbar and will not have an adverse effect on the melt. Furthermore, due to the large cross-section and low resistance of the busbar, it has good resistance to current surges.

[0029] The overall excitation fuse features a partially sealed design with no vent holes, preventing foreign objects from contaminating the break point and also preventing high-temperature arcs from erupting from the casing and damaging surrounding components, thus improving the protection level. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the three-dimensional appearance structure of the excitation fuse.

[0031] Figure 2 yes Figure 1 Schematic diagram of the main sectional view structure.

[0032] Figure 3 yes Figure 1 A schematic diagram of the first side section structure.

[0033] Figure 4 yes Figure 1 The second side section view of the structure.

[0034] Figure 5 This is a schematic diagram showing the relationship between the piston and the conductive busbar when viewed from the side.

[0035] Figure 6 This is a schematic diagram showing the relationship between the piston and the conductive busbar in a main cross-section.

[0036] Figure 7 This is a schematic diagram of a piston structure.

[0037] Figure 8 This is a schematic diagram of a conductive busbar with a flat plate structure.

[0038] Figure 9 This is a schematic diagram of the pre-break misalignment setting structure of the conductive busbar.

[0039] Electronic ignition tube 401, top cover 402, upper housing 403, piston 404, first conductive bar 405, second conductive bar 406, lower housing 407, third conductive bar 408, piston push plate 409, base plate 410, inter-electrode insulation 411, fuse housing 412, fuse cover 413, upper cutter 414, lower cutter 415, molten material 416, arc extinguishing medium 417, molten material 418, connector 419, wire harness 420, molten material cover 421, impact end (404a, 404b, 404c), pre-break (405a, 406a, 408a). Detailed Implementation

[0040] The motor domain protection fuse of the present invention includes a housing, an electronic ignition tube, a piston, a first conductive busbar, a second conductive busbar, a third conductive busbar, and a fusible element. A channel for piston displacement is provided in the housing, and the piston is disposed in the channel. The first, second, and third conductive busbars are staggered and pass through the housing. The pre-break points of the first, second, and third conductive busbars pass through the channel where the piston is located and are situated on the piston's displacement path. A fusible element is connected in parallel to each of the first, second, and third conductive busbars. Cavities are provided in the housing outside the channel where the piston is located, corresponding to the fusible elements, and the fusible elements pass through the corresponding cavities. The electronic ignition tube is disposed on the housing. The high-pressure gas released by the electronic ignition tube drives the piston to move, simultaneously disconnecting the first, second, and third conductive busbars, causing the fusible element to melt.

[0041] The following describes preferred embodiments in detail with reference to the accompanying drawings. The directional terms used are for reference only and do not constitute a limitation on the technical solutions of this invention.

[0042] Motor protection fuse, see Figures 1 to 7 The system includes a housing, a piston 404, a first conductive bar 405, a second conductive bar 406, and a third conductive bar 408. The housing is made of insulating material and is composed of a top cover 402, an upper housing 403, a lower housing 407, and a base plate 410, which are sequentially fitted together and fixed together by bolts. The top cover 402, upper housing 403, lower housing 407, and base plate 410 are all sealed, without any vent holes. Sealing rings and silicone sealant are used between the contact surfaces of the mating parts, ensuring excellent overall sealing performance of the housing. This prevents foreign objects from contaminating the fracture surface and also prevents high-temperature arcing from damaging surrounding components. A cavity is provided within the housing for the displacement of the piston 404.

[0043] The top cover 402 is shaped to fit the shape of the electronic ignition tube 401, serving to mount and fix the electronic ignition tube 401 and restrict its displacement. The contact surface between the electronic ignition tube 401 and the top cover 402 is sealed. A connector 419 and a wiring harness 420 are provided at the trigger signal receiving end of the electronic ignition tube 401 to facilitate connection with an external control terminal that sends trigger signals. Sufficient space is provided within the top cover 402 for the high-pressure gas released by the electronic ignition tube 401. The electronic ignition tube 401, as a gas generating device, is able to release high-pressure gas upon receiving a trigger signal. The end of the electronic ignition tube that releases high-pressure gas is located within the housing, and the released high-pressure gas drives the piston 404, which is disposed within the housing, to move.

[0044] A piston 404, a first conductive bar 405, a second conductive bar 406, and a third conductive bar 408 are disposed within the housing. The first conductive bar 405, the second conductive bar 406, and the third conductive bar 408 are arranged with insulating intervals between the contact surfaces of the upper housing 403 and the lower housing 407, and are staggered in height. To improve the insulation performance between the first conductive bar 405, the second conductive bar 406, and the third conductive bar 408, an inter-electrode insulating element 411 is provided at the contact surface between the upper housing 403 and 407 to insulate the first conductive bar 405, the second conductive bar 406, and the third conductive bar 408 from each other. The specific arrangement can vary, such as the inverted triangular arrangement shown in the diagram, where the first conductive bar 405 and the second conductive bar 406 are spaced apart on opposite sides of the housing, and the third conductive bar 408 is located in the middle of the housing, situated on a different plane from the first conductive bar 405 and the second conductive bar 406.

[0045] Pre-breaks are provided on the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408 located within the housing. These pre-breaks are situated within the channels through which the piston 404 is displaced, and are located along the displacement path of the piston 404. The pre-breaks of the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408 are positioned within the channels through which the piston 404 is displaced, and sufficient insulation distance is maintained between them. The pre-breaks are designed as planar structures. To facilitate the breaking of the pre-breaks, weak points that reduce the mechanical strength of the conductive busbars are provided, such as grooves that reduce the thickness of the conductive busbars, such as U-shaped grooves, V-shaped grooves, or a combination of both. Pre-breaks are formed on the upper and lower sides of the conductive busbars, with U-shaped grooves, V-shaped grooves, or a combination of both, extending through the width of the conductive busbars. V-shaped grooves are preferred. When the pre-break is a double-sided "V"-shaped groove, this structure ensures both current flow and the timely breaking of the conductive busbars. To make the structure more compact, the pre-breaks of the three conductive busbars (405, 406, 408) are respectively provided with notch shapes in the width direction, so that the pre-breaks of the three conductive busbars are also arranged in a staggered manner in the channel of the housing for piston displacement, so that the movement of the three impact ends of piston 404 does not interfere with each other, thus forming a clearance. Because the first conductive busbar 405, the second conductive busbar 406, and the second conductive busbar 408 are arranged in a compact, staggered configuration, the connection ends located outside the housing are very close together, making it inconvenient for each conductive busbar to connect to an external circuit. Therefore, the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408 are arranged in a U-shape. The first conductive busbar 405 and the second conductive busbar 406 located on opposite sides of the housing are arranged in a U-shape inside the housing, while the third conductive busbar 408 is arranged in an inverted U-shape inside the housing. This allows the pre-breaks of the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408 inside the housing to be arranged with a shorter insulation distance, thereby shortening the length of the piston 404. This allows the connection ends located outside the housing to be arranged at the furthest relative distance, increasing the space between the connection ends of each conductive busbar and facilitating connection to an external circuit.

[0046] Piston 404, made of insulating material, is disposed in a channel within the housing for piston 404 to move, and corresponds to the pre-cut sections of the first conductive bar 405, the second conductive bar 406, and the third conductive bar 408. (See attached image) Figures 5 to 7The piston 404 has three stepped impact ends (404a, 404b, 404c), corresponding to the pre-cut surfaces of the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408, respectively. The three impact ends of the piston 404 have the same stroke distance from the pre-cut surfaces of the three conductive busbars. The end face of the three impact ends of the piston 404 facing the corresponding conductive busbar is designed as a cutting blade to match the pre-cut surface of the conductive busbar, and the stepped portion has high mechanical strength, facilitating concentrated force to cut the conductive busbar. To prevent malfunction of the piston 404, a limiting structure is provided at the contact surface between the piston 404 and the housing. Specifically, the limiting structure can be configured as follows: limiting protrusions are spaced apart on the outer periphery of the end of the piston 404 away from the conductive busbar. These limiting protrusions cooperate with limiting grooves on the inner wall of the housing cavity, thus limiting the initial position of the piston 404. The piston 404 is in sealed contact with the inner wall of the housing cavity. To achieve this sealed contact, an annular groove is provided around the outer periphery of the piston 404, and a sealing ring is placed in the annular groove. The sealing contact between the piston and the inner wall of the housing is achieved through the sealing ring.

[0047] The first conductive busbar 405 and the second conductive busbar 406 are connected in parallel with melt 418, and the third conductive busbar 408 is connected in parallel with melt 416. When the conductive busbars are disconnected, current flows through melt 416 and melt 418. During normal flow, almost all current flows through each conductive busbar, and the current flowing through melt 416 and melt 418 is negligible. To better accommodate the melts (416, 418), corresponding cavities for accommodating the melts (416, 418) are respectively provided in the shell portion between the outer periphery of the displacement channel of the piston 404 and the outer wall of the shell. To make full use of the existing space in the shell, preferably, the cavity containing melt 418 connected in parallel to the first conductive busbar 405 and the second conductive busbar 406 is located in the upper part of the shell, and the cavity containing melt 416 connected in parallel to the third conductive busbar 408 is located in the lower part of the shell. Two cavities corresponding to the two melts 418 connected in parallel on the first conductive bus 405 and the second conductive bus 406 are symmetrically distributed on opposite sides of the displacement channel of the piston 404, and both are arc-shaped. Correspondingly, the melts 418 are also arc-shaped and set in the corresponding cavities, that is, the shape of the melt matches the shape of the cavity. To avoid the melts 418 from contacting the inner wall of the cavity, a support structure is provided at the bottom of the cavity to support and position the melts 418 away from the inner wall of the cavity. A melt cap 421 is provided on the cavity where the melts 418 are located to seal the cavity. A filling hole for filling the cavity with the arc-extinguishing medium 417 is provided on the melt cap, and the narrow neck of the melts 418 is located in the arc-extinguishing medium 417.

[0048] A fuse structure is provided in the cavity accommodating the fusible element 416. The fuse structure includes a sealed fuse housing 412 and a fuse cover 413. An arc-extinguishing medium 417 is filled in the fuse structure. The fusible element 416 passes through the arc-extinguishing medium 417 in the fuse structure formed by the fuse housing 412 and the fuse cover 413, with the neck of the fusible element 416 located in the arc-extinguishing medium 417. The fuse cover 413 is designed with a concave structure, and protrusions are provided at the bottom of the fuse cover 413 where it mates with the fuse housing 412. Through the engagement of the protrusions, the fusible element 416 is pressed between the engaging protrusions of the fuse housing 412 and the fuse cover 413, thereby positioning the fusible element 416. Preferably, the fuse structure is pre-assembled as a module, and during assembly, the fuse structure is directly placed in the corresponding cavity and then fixed in the cavity by the base plate 410. The fuse structure includes at least one displacement channel, the displacement direction of which is the same as the piston displacement direction, through which the molten metal 416 passes. A displaceable molten metal cutter assembly is disposed within the displacement channel, with the molten metal 416 located in the displacement path of the cutter assembly. The end of the cutter assembly facing the piston 404 protrudes from the fuse structure. A piston pusher plate 409 is disposed at the protruding end of the cutter assembly, located in the displacement path of the piston 404. Preferably, the cutter assembly includes an upper cutter 414 and a lower cutter 415 nested together, with the weak point of the molten metal 416 being held between the upper cutter 414 and the lower cutter 415. When the piston 404 pushes the piston pusher plate 409, the piston pusher plate 409 pushes the cutter assembly to move, breaking the molten metal 416. A limiting protrusion is provided on the outer periphery of the lower cutter 415. The limiting protrusion cooperates with the limiting groove of the displacement channel to limit the initial position of the melt cutter assembly.

[0049] The design features three busbars, with two busbars carrying AC current and one busbar carrying DC current, providing simultaneous protection against both AC and DC current in the motor domain. This significantly reduces the space required for motor domain use and lowers costs.

[0050] The working principle is as follows:

[0051] Under normal current flow conditions, alternating current flows through the first busbar 405 and the second busbar 406, while direct current flows through the third busbar 408. Only a very weak current flows through the molten material (416, 418), so the product can be considered as a conductor.

[0052] Disconnection Operation: When a fault current occurs, the external control system sends a trigger signal to the electronic ignition tube 401. The electronic ignition tube 401 ignites and releases high-pressure gas. The high-pressure gas pushes the piston 404 to break through the limit structure and move downward. At the same time, it breaks the pre-break of the first conductive busbar 405, the second conductive busbar 406, and the third conductive busbar 408 to form a break. After the conductive busbars are disconnected, the current flows completely through the molten elements (416, 418). The molten elements (416, 418) begin to melt from the narrow diameter, and the AC side is completely disconnected. The action ends, and the current of the two motors is disconnected. The DC side molten element 416 begins to melt in the arc-extinguishing medium 417. As the piston 404 continues to move downward, it pushes the piston push plate 409 to work with the upper cutter 414 and the lower cutter 415 to completely break the molten element 416. The action ends, the DC side is disconnected, and the strength of the base plate ensures that it can withstand the final impact pressure.

[0053] When applied to the motor domain, the AC current at the motor end flows through the first busbar 405 and the second busbar 406, while the DC current at the control end (motor domain IGBT module DC current) flows through the third busbar 408. When the fuse 418 melts, the two motor currents on the AC side are disconnected; when the fuse 416 is completely broken, the control end on the DC side is completely disconnected.

[0054] In some embodiments, the first conductive bus 405, the second conductive bus 406, and the third conductive bus 408 are flat plates and are staggered in height, see [reference]. Figures 8 to 9 The first conductive busbar 405 and the second conductive busbar 406 are horizontally parallel and insulated from each other. The third conductive busbar 408 is located below the first conductive busbar 405 and the second conductive busbar 406 at a certain insulated distance and is horizontally parallel and spaced from the first conductive busbar 405 and the second conductive busbar 406 in the vertical direction. The two connecting ends of the third conductive busbar 408 located outside the housing are directly opposite to the connecting ends of the first conductive busbar 405 and the second conductive busbar 406 located outside the housing. The first conductive busbar 405, the second conductive busbar 406 and the third conductive busbar 408 in the displacement channel of the piston 404 located inside the housing are respectively provided with notches in the width direction to form pre-breaks (405a, 406a and 408a). The width of the pre-breaks (405a, 406a and 408a) is smaller than the width of the connecting ends of the first conductive busbar 405, the second conductive busbar 406 and the third conductive busbar 408. The pre-break 408a of the third conductive bus 408, the pre-break 405a of the first conductive bus 405, and the pre-break 406a of the second conductive bus 406 are staggered in height, and the notches in the width direction of the three conductive buses form clearance spaces for the impact ends of the piston 404, so that the actions of each conductive bus when disconnected do not interfere with each other. Of course, in order to improve the insulation performance between the three conductive buses, inter-electrode insulation components are also provided between the three conductive buses.

[0055] Figures 8 to 9The structure of the excitation fuse is more compact, and the width dimension is relatively smaller. Figure 1 Its width dimension is smaller.

Claims

1. A motor protection fuse, characterized in that, The device includes a housing, an electronic ignition tube, a piston, a first conductive busbar, a second conductive busbar, a third conductive busbar, and a molten material. A channel for piston displacement is provided in the housing, and the piston is disposed within the channel. The first, second, and third conductive busbars are staggered and pass through the housing. Pre-cut sections of the first, second, and third conductive busbars pass through the channel containing the piston and are located on the piston's displacement path. The molten material is connected in parallel to each of the first, second, and third conductive busbars. Cavities corresponding to the molten material are provided in the housing outside the channel containing the piston, and the molten material passes through the corresponding cavities. The electronic ignition tube is disposed on the housing. High-pressure gas released by the electronic ignition tube drives the piston to move, simultaneously disconnecting the first, second, and third conductive busbars, causing the molten material to melt.

2. The motor domain protection fuse according to claim 1, characterized in that, The pre-break points of the first, second, and third conductive busbars are staggered in height, and the piston has three impact ends arranged in a stepped manner, with each impact end corresponding to one conductive busbar; the three impact ends of the piston have the same stroke distance from the pre-break point of the corresponding conductive busbar.

3. The motor domain protection fuse according to claim 1, characterized in that, The first and second conductive busbars are located on opposite sides of the housing, and the third conductive busbar is located in the middle of the housing.

4. The motor domain protection fuse according to claim 1, characterized in that, The cavities through which the melt passes are distributed in the upper and lower parts of the shell outside the piston displacement channel; the cavities are filled with an arc-extinguishing medium.

5. The motor domain protection fuse according to claim 4, characterized in that, The cavity located in the upper part of the housing is formed by a groove opened on the housing and a melt cap disposed on the groove, and the cavity located in the lower part of the housing is formed by a groove opened on the housing and a bottom plate.

6. The motor domain protection fuse according to claim 5, characterized in that, The cavities are respectively provided on the upper part of the housing and on opposite sides of the piston displacement channel; the melts connected in parallel on the first and second conductive bars are respectively disposed in the corresponding cavities on the upper part of the housing, the shape of the melts matches the shape of the cavities, and a support structure is provided at the bottom of the cavity to support the melts and position them.

7. The motor domain protection fuse according to claim 5, characterized in that, The molten material connected in parallel on the third conductive busbar is disposed in the cavity at the lower part of the housing. A fuse structure is disposed in the cavity, and the base plate provides support and fixation for the fuse structure. The fuse structure is filled with an arc-extinguishing medium, and the molten material connected in parallel on the third conductive busbar passes through the arc-extinguishing medium in the fuse structure.

8. The motor domain protection fuse according to claim 7, characterized in that, The fuse structure is provided with a melt cutter displacement channel along the piston displacement direction, and a melt cutter assembly is provided in the melt cutter displacement channel. The melt passes through the melt cutter displacement channel and is located on the displacement path of the melt cutter assembly. The melt cutter assembly protrudes from the fuse structure at one end toward the piston. A piston pusher plate is provided at the end of the melt cutter assembly that protrudes from the fuse structure. The piston pusher plate is located on the piston displacement path. When the piston cuts the conductive busbar, the piston pushes the piston pusher plate and the melt cutter assembly to pull off the melt connected in parallel to the third conductive busbar.

9. The motor domain protection fuse according to claim 8, characterized in that, The fuse structure includes a fuse housing and a fuse cover, with corresponding protrusions at the middle of the fuse cover and the fuse housing; the fusible element passes through the cavity formed by the fuse housing and the fuse cover, and is held between the protrusions of the fuse cover and the fuse housing; the cavity formed by the fuse housing and the fuse cover is filled with an arc-extinguishing medium, which is located outside the displacement channel of the fusible element cutter.

10. The motor domain protection fuse according to claim 1, characterized in that, The housing is an insulated and sealed housing.

11. The motor domain protection fuse according to claim 1, characterized in that, An inter-electrode insulating element is provided between each of the conductive bars, and the inter-electrode insulating element is located outside the piston displacement channel.

12. The motor domain protection fuse according to claim 1, characterized in that, The first conductive busbar and the second conductive busbar are arranged parallel to each other in the horizontal direction and spaced apart. The third conductive busbar is arranged parallel to the first conductive busbar and the second conductive busbar in the vertical direction and is directly opposite to them. The first conductive busbar, the second conductive busbar and the third conductive busbar located in the piston displacement channel have notches on at least one side in the width direction to form the pre-break. The pre-breaks of the first conductive busbar, the second conductive busbar and the third conductive busbar are arranged with their heights staggered.

13. The motor domain protection fuse according to claim 1, characterized in that, The first and second busbars are configured for three-phase AC power in the motor domain, and the third busbar is configured for DC power in the IGBT module of the motor domain.

Images