Excitation type fuse

Abstract

The utility model discloses an excitation type fuse, which comprises an upper shell, a lower shell, a trigger device arranged on the upper shell and a conductive part arranged between the upper shell and the lower shell, and the conductive part is conductive before the trigger device is started; the conductive part comprises a middle section, a first conductive section and a second conductive section, and the first conductive section and the second conductive section are fixedly connected with the middle section through a first bending part and a second bending part respectively; a first arc extinguishing grid plate group and a second arc extinguishing grid plate group which are used for arc extinguishing are arranged in the lower shell, each of the first arc extinguishing grid plate group and the second arc extinguishing grid plate group comprises a plurality of metal plates which are arranged at intervals along the horizontal direction, and a slit which is distributed along the vertical direction is formed between two adjacent metal plates; the first arc extinguishing grid sheet group and the second arc extinguishing grid sheet group are respectively positioned below the first bending part and the second bending part; after the trigger device is started, the joints of the first bending part and the middle section and the joints of the second bending part and the middle section are cut off, the first bending part and the second bending part are bent towards the lower shell, and the excitation type fuse is better in arc extinguishing effect and higher in safety.

Description

Technical Field

[0001] The utility model relates to the field of power control and circuit protection, in particular to an excitation type fuse. Background Art

[0002] Traditional fuses are the fragile parts of circuits or electrical appliances. Once a fault occurs in the circuit (such as overload current), the traditional fuse will blow and disconnect the circuit in time. In the field of new energy and wind and solar energy storage, when the system detects circuit anomalies (such as battery failure, overcharging, current anomalies) and environmental anomalies (such as natural disasters, extreme temperatures, immersion in water), the system needs the fuse to actively and quickly cut off the circuit to ensure the safety of personnel and equipment. Obviously, traditional fuses cannot meet the above requirements, and incentive fuses came into being.

[0003] The current excitation-type fuses, after receiving the system's cut-off command, use a power source such as gunpowder to quickly and mechanically cut off the circuit. How to quickly and stably cut off the circuit and ensure insulation safety after cutting off is one of the technical difficulties; how to solve the arcing (or arc extinguishing solution) of the high-voltage break and improve the explosion-proof safety of the device is the second technical difficulty.

[0004] An explosive circuit breaker with an arc separation plate in the prior art has a busbar that is punched and bent on one side, and an arc separation plate that captures and attracts the arc is arranged on the opposite side. The arc separation plates are arranged at intervals in the vertical direction. In the process of the busbar being cut and bent downward, there is always an angle between the busbar and the arc separation plate and the slit, which results in the arc striking effect and demand of the arc separation plate decreasing layer by layer. The lower the separation plate is, the less effective it is. The material utilization rate is low, and arc separation plates of sufficient size need to be arranged on the upper layer to play a role. In terms of the breaking buffer, this patent is concentrated on one side, so more reinforcement design is required on the impact side of the lower object, which is not conducive to the injection molding of the parts. The multiple layers of horizontally arranged arc separation plates also have high assembly cost requirements for the parts, resulting in high overall manufacturing costs. Utility Model Content

[0005] The utility model aims to provide a new excitation type fuse.

[0006] In order to achieve the above object, the technical solution adopted by the utility model is: an excitation type fuse, comprising:

[0007] Upper shell,

[0008] A lower housing having a lower accommodating chamber;

[0009] a trigger device, which is arranged on the upper housing;

[0010] a conductive portion disposed between the upper housing and the lower housing; before the trigger device is activated, the conductive portion is configured to be conductive;

[0011] The conductive portion comprises a middle section, a first conductive section, a second conductive section and a bending section, the bending section comprises a first bending section and a second bending section, the first conductive section and the middle section are fixedly connected via the first bending section, and the second conductive section and the middle section are fixedly connected via the second bending section;

[0012] An arc-extinguishing grid group for arc extinguishing is provided in the lower housing, the arc-extinguishing grid group comprises a first arc-extinguishing grid group and a second arc-extinguishing grid group, each of which comprises a plurality of metal plates spaced apart in the horizontal direction, and a slit distributed in the vertical direction is formed between two adjacent metal plates; the first arc-extinguishing grid group is located below the first bent portion, and the second arc-extinguishing grid group is located below the second bent portion;

[0013] After the trigger device is activated, the connection between the first bending portion and the middle section is cut off, the connection between the second bending portion and the middle section is cut off, and the first bending portion and the second bending portion are respectively bent toward the lower shell.

[0014] The excitation type fuse provided by the present invention has a conductive part that realizes normal conduction of the circuit before the trigger device is triggered; when an accident occurs and the circuit needs to be cut off, the trigger device is activated, and at this time, the two bent parts of the cut-off conductive part are respectively bent downward into the lower accommodating cavity, and at the same time, the arc in the bending process is cut off by the arc extinguishing grid group at the corresponding position and introduced into the slits distributed in the vertical direction, which has a high arc extinguishing efficiency.

[0015] In some embodiments, each of the metal plates has an arc-shaped edge, so that when the free end of the bending portion is bent, the distance from the metal plate at the corresponding position remains substantially unchanged. During the downward bending of the bending portion, the arc-shaped edge can continuously capture and absorb the arc, thereby improving the arc extinguishing effect.

[0016] In some embodiments, the excitation type fuse further comprises a fixing seat fixedly connected to the lower housing, the fixing seat being arranged between the first arc extinguishing grid set and the second arc extinguishing grid set; after the bending portion and the middle section are cut off, the top of the fixing seat supports the middle section, so as to prevent the middle section from flipping and falling into the lower accommodating cavity to cause safety hazards.

[0017] In some embodiments, the lower shell is further provided with a buffer portion, the buffer portion is provided on the side wall of the lower shell, and the buffer portion is configured to absorb the kinetic energy of any bending portion and generate deformation. The buffer portion is provided to ensure protection of the lower shell.

[0018] In some embodiments, each of the metal plates includes a first supporting wall and a second supporting wall, the first supporting wall being fixedly connected to the bottom wall of the lower accommodating cavity; and / or,

[0019] The excitation type fuse further comprises a fixing seat fixedly connected to the lower shell, wherein the fixing seat is arranged between the first arc extinguishing grid plate group and the second arc extinguishing grid plate group; the second supporting wall is fixedly connected to the fixing seat.

[0020] In some embodiments, a groove for shunting the arc is formed on the top wall of each metal plate. After the conductive part is cut off, the arc generated at the break can be cut by the groove, and the arc can also be cut by the metal plates arranged at intervals, so the arc extinguishing effect is better.

[0021] In some embodiments, the bottom wall of the lower shell is also provided with an air flow channel connected to the outside.

[0022] In some embodiments, the airflow channel includes a groove and at least one pressure relief port; the groove is located at a corresponding position of the lower accommodating chamber, and the pressure relief port is located at a corresponding position of the side wall of the lower shell; the pressure relief port and the groove are not in the same plane to prevent the arc from leaking through the airflow channel.

[0023] In some embodiments, the trigger device includes a firing part and a power part, the power part is arranged above the firing part, and the firing part is arranged above the conductive part; the power part is used to drive the firing part to move downward, and the firing part is used to cut off the conductive part.

[0024] In some embodiments, the firing portion includes two firing arms extending downward, and the two firing arms are used to cut off the connection between the middle section and the two bent portions respectively.

[0025] The firing portion between the two firing arms is a pressing portion, which is used to press against the middle section when the trigger device is activated. The pressing portion can limit the displacement of the middle section, thereby ensuring insulation safety after the circuit is cut off.

[0026] In some embodiments, the distance between the two firing arms is slightly greater than the length of the middle section to prevent the middle section from flipping and falling into the lower accommodating chamber when the firing portion moves downward.

[0027] In some embodiments, the firing part includes two firing arms extending downward, and the two firing arms are used to cut off the connection between the middle section and the two bending parts respectively; two limiting protrusions and an arm contact part are provided at the end of each firing arm, and before the trigger device is activated, the arm contact part abuts against the upper surface of the conductive part, and the two limiting protrusions are respectively located on both sides of the conductive part to prevent the firing part from rotating relative to the conductive part. The cooperation between the limiting protrusion and the conductive part can not only realize the positioning between the firing part and the conductive part, but also ensure that the firing part can accurately cut off the conductive part.

[0028] In some embodiments, the excitation type fuse also includes a pre-positioning mechanism to position the conductive part; the pre-positioning mechanism includes a first pre-positioning part arranged on the lower shell body, and the conductive part is provided with a second pre-positioning part that cooperates with the first pre-positioning part; and / or the first pre-positioning part is a positioning column, and the second pre-positioning part is a hole opened on the conductive part that is adapted to the positioning column.

[0029] In some embodiments, the pre-positioning mechanism comprises two groups. Preferably, the two groups of pre-positioning mechanisms are eccentrically arranged to achieve a fool-proof function.

[0030] In some embodiments, the upper shell includes a first upper accommodating chamber in a cylindrical shape, the power unit is a gas generating device for generating gas, the firing unit is movably arranged in the first upper accommodating chamber under the push of the gas, and a sealing mechanism is arranged between the side wall of the firing unit and the side wall of the first upper accommodating chamber. The sealing mechanism can improve the airtightness, so that the firing unit can quickly cut off the conductive part under the push of the gas.

[0031] In some embodiments, a power limiter is provided between the power unit and the upper housing to prevent the power unit from rotating, and the power limiter is used to maintain the stability of the power unit and ensure that the power unit can work normally.

[0032] In some embodiments, a firing limit portion for preventing the firing portion from rotating is provided between the firing portion and the conductive portion; and / or a firing limit portion for preventing the firing portion from rotating is provided between the firing portion and the upper shell.

[0033] In some embodiments, the firing part includes two firing arms extending downward, and the two firing arms are used to cut off the connection between the middle section and the two bending parts respectively; two limiting protrusions are arranged at the end of each firing arm, and before the trigger device is activated, the two limiting protrusions are respectively located on both sides of the conductive part, and the limiting protrusions and the side walls of the conductive part constitute the firing limiting part. The cooperation between the limiting protrusions and the side walls of the conductive part can not only realize the positioning between the firing part and the conductive part, but also prevent the relative rotation between the two, so as to ensure that the firing part can accurately cut off the conductive part.

[0034] In some embodiments, the lower housing includes a first lower housing and a second lower housing that are detachably connected, the first lower housing is open at both ends, and the inner wall of the first lower housing constitutes the side wall of the lower accommodating chamber; the second lower housing is located below the first lower housing, and the arc-extinguishing grid assembly is fixedly arranged on the top wall of the second lower housing. Such an arrangement facilitates the assembly of the lower housing, and also facilitates the installation or replacement of the arc-extinguishing grid assembly.

[0035] In some embodiments, the excitation type fuse also includes a fixing base fixedly connected to the lower shell body, and the fixing base is arranged between the first arc extinguishing grid plate group and the second arc extinguishing grid plate group; each of the metal plates includes a first support wall and a second support wall, and the bottom wall of the lower accommodating cavity and the side wall of the fixing base are respectively provided with a card groove, the first support wall is clamped in the card groove in the lower accommodating cavity, and the second support wall is clamped in the card groove of the fixing base.

[0036] In some embodiments, the buffer portion includes a buffer wall and a buffer cavity, the buffer wall is fixedly connected to the lower shell, the buffer wall constitutes a part of the side wall of the lower accommodating cavity, the buffer cavity is located on the side of the buffer wall away from the lower accommodating cavity, and when the bending portion is bent and abuts against the buffer wall, the buffer wall deforms toward the buffer cavity. The buffer portion can absorb the kinetic energy generated by the impact of the bending portion, thereby protecting the lower shell.

[0037] In some embodiments, the buffer wall includes a buffer fixed end and a buffer free end arranged opposite to the buffer fixed end. When the bending portion is bent and abuts against the buffer wall, the buffer free end swings toward the buffer cavity; the buffer free end is located above the buffer fixed end.

[0038] In some embodiments, the pressing portion includes a plurality of ridges distributed along a length direction transverse to the conductive portion.

[0039] In some embodiments, each of the metal plates extends along the width direction of the conductive portion, and a plurality of the metal plates are arranged in parallel along the length extension direction of the conductive portion; the height of each of the metal plates gradually decreases from the fixing seat to the side wall of the lower accommodating cavity, so that each of the arc-extinguishing grid sets forms an arc-shaped edge, so that when the free end of the bent portion is bent at the bent portion, the distance from the arc-extinguishing grid set at the corresponding position remains substantially unchanged; and / or,

[0040] A groove for breaking the arc is provided on the top of each metal plate.

[0041] In some embodiments, a bottom wall of the lower shell is provided with a slot, the bottom of the metal plate is snapped into the slot, and the metal plate is not directly connected to the fixing seat.

[0042] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art: in the excitation type fuse of the utility model, the multiple metal plates of the arc extinguishing grid group are arranged at intervals in the horizontal direction, so that a slit distributed in the vertical direction is formed between two adjacent metal plates. In this way, the metal plate can continuously divide the arc, and the slit can continuously capture and absorb the arc, thereby improving the arc extinguishing effect, enhancing the safety performance of the excitation type fuse, and also improving the utilization rate of the metal plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Attached Figure 1 It is a three-dimensional structural schematic diagram of an excitation type fuse according to Embodiment 1 of the utility model;

[0044] Attached Figure 2 For attachment Figure 1 Side view of

[0045] Attached Figure 3 For the attachment Figure 2 A cross-sectional view taken along the AA axis, wherein the trigger device is in an unactivated state;

[0046] Attached Figure 4 For attachment Figure 3 Schematic diagram after the trigger device is activated;

[0047] Attached Figure 5 For attachment Figure 1 A schematic diagram of an excitation type fuse after removing the upper housing and the trigger device;

[0048] Attached Figure 6 For attachment Figure 5 A three-dimensional schematic diagram of the structure of the middle part;

[0049] Attached Figure 7 For attachment Figure 6 A schematic diagram of the three-dimensional structure of the second lower shell;

[0050] Attached Figure 8 For attachment Figure 6 A schematic diagram of the three-dimensional structure of the middle fixing seat;

[0051] Attached Fig. 9 For attachment Figure 6 Schematic diagram of the three-dimensional structure of the metal plate;

[0052] Attached Fig.10 It is a schematic diagram of the three-dimensional structure of the firing portion of Example 1;

[0053] Attached Fig.11 For attachment Fig.10 Schematic diagram of the three-dimensional structure from another perspective;

[0054] Attached Fig.12 is a schematic diagram of the three-dimensional structure of the conductive part of Example 1;

[0055] Attached Fig.13 It is a schematic diagram of the three-dimensional structure of the power unit in Example 1;

[0056] Attached Fig.14 It is a longitudinal cross-sectional schematic diagram of an excitation type fuse of Example 2;

[0057] Attached Fig.15 It is a three-dimensional schematic diagram of a partial structure of an excitation type fuse of Example 2;

[0058] Attached Fig.16 For attachment Fig.15 A schematic diagram of the three-dimensional structure of the second lower shell;

[0059] Attached Fig.17 For attachment Fig.15 A schematic diagram of the three-dimensional structure of the middle fixing seat;

[0060] Attached Fig.18 For attachment Fig.15 Schematic diagram of the three-dimensional structure of the arc-extinguishing grid group;

[0061] in:

[0062] 1. upper housing; 11. first upper accommodating chamber; 12. second upper accommodating chamber;

[0063] 2. lower shell; 20. lower accommodating chamber; 21. first lower shell; 210. opening; 211. buffer portion; 2111. buffer wall; 2112. buffer chamber; 212. positioning column; 213. limiting portion; 22. second lower shell; 221. air flow channel; 2211. groove; 2212. pressure relief port; 222. mounting groove;

[0064] 3. trigger device; 30. impact groove; 31. firing part; 311. firing arm; 3111. limiting convex block; 3112. arm contact part; 312. pressing part; 313. annular groove; 314. sealing ring; 32. power part; 321. limiting surface;

[0065] 4. conductive portion; 41. middle segment; 42. first conductive segment; 43. second conductive segment; 44. bending portion; 44a. first bending portion; 44b. second bending portion; 45. hole;

[0066] 5. arc-extinguishing grid group; 5a. first arc-extinguishing grid group; 5b. second arc-extinguishing grid group; 51. metal plate; 511. arc-shaped edge; 512. first supporting wall; 513. second supporting wall; 514. groove; 52. slit;

[0067] 6. Fixed seat; 61. Accommodating groove; 62. Support portion; 63. Fixed portion; 631. First clamping groove; 632. Second clamping groove; 70. Clamping groove. DETAILED DESCRIPTION

[0068] The technical solution of the utility model is described in detail below in conjunction with the accompanying drawings and specific embodiments, so that the advantages and features of the utility model can be more easily understood by those skilled in the art. Obviously, the embodiments described in this application are only part of the embodiments of the application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0069] Example 1

[0070] See also Figures 1 to 3An excitation type fuse is shown, which includes an upper shell 1, a lower shell 2, a trigger device 3 and a conductive part 4, wherein the trigger device 3 is arranged on the upper shell 1, and the conductive part 4 is arranged between the upper shell 1 and the lower shell 2. Before the trigger device 3 is activated, the conductive part 4 can conduct electricity, so that the circuit is turned on. The conductive part 4 has a middle section 41, a first conductive section 42, a second conductive section 43 and a bending section 44, and the bending section 44 includes a first bending section 44a and a second bending section 44b. The first conductive section 42 is fixedly connected to the middle section 41 through the first bending section 44a, and the second conductive section 43 is fixedly connected to the middle section 41 through the second bending section 44b. Each bending section 44 has a fixed end close to the conductive section (the first conductive section 42 or the second conductive section 43), and each bending section 44 also has a free end close to the middle section 41. A downwardly concave cutout is formed on the upper surface of the two connecting parts of the two bending parts 44 and the middle section 41, so that the bending parts 44 can be cut off at the cutout after receiving downward external force. The cutout is "V" shaped. At the same time, an upwardly concave notch is also provided at the fixed end of the bending part 44, so that the swing axis of the free end of the bending part 44 is at the corresponding position of the notch when swinging. The notch is semicircular.

[0071] After the trigger device 3 is activated, the connection between the first bending portion 44a and the middle section 41 is cut off, the connection between the second bending portion 44b and the middle section 41 is cut off, the first bending portion 44a and the second bending portion 44b are respectively bent toward the lower shell 2, at this time, the free end of the bending portion 44 swings around the fixed end, the conductive portion 4 loses its conductive function, and the circuit is cut off.

[0072] The lower housing 2 has a lower accommodating chamber 20, and an arc extinguishing grid group 5 for extinguishing arcs is provided in the lower housing 2, and the arc extinguishing grid group 5 is located in the lower accommodating chamber 20. The arc extinguishing grid group 5 includes a first arc extinguishing grid group 5a and a second arc extinguishing grid group 5b, wherein the first arc extinguishing grid group 5a is located below the first bending portion 44a, and is used to capture and absorb the arc generated by the first bending portion 44a; the second arc extinguishing grid group 5b is located below the second bending portion 44b, and is used to capture and absorb the arc generated by the second bending portion 44b.

[0073] The first arc-extinguishing grid set 5a and the second arc-extinguishing grid set 5b respectively include a plurality of metal plates 51 spaced apart in the horizontal direction, and a slit 52 distributed in the vertical direction is formed between two adjacent metal plates 51. Since the two bending portions 44 are bent downward after the trigger device 3 is activated, and the vertically distributed slit 52 is consistent with the movement direction of the bending portion 44, the slit 52 can better capture and absorb the arc, thereby achieving a better arc extinguishing effect.

[0074] In this embodiment, the trigger device 3 includes a firing part 31 and a power part 32. The power part 32 is arranged above the firing part 31. The firing part 31 is arranged above the conductive part 4. The power part 32 is used to drive the firing part 31 to move downward. The firing part 31 is used to cut off the conductive part 4. Figure 3 As shown, the power part 32 is arranged on the upper part of the upper shell 1 , and the upper shell 1 includes a first upper accommodating chamber 11 in a columnar shape. The first upper accommodating chamber 11 is located below the power part 32 , and the firing part 31 is located in the first upper accommodating chamber 11 .

[0075] Specifically, the upper shell 1 is further provided with a second upper accommodating chamber 12, which is located above the first upper accommodating chamber 11 and the two are interconnected, and the power unit 32 is a gas generating device for generating gas, and the power unit 32 is located in the second upper accommodating chamber 12. After the trigger device 3 is activated, the gas generated by the power unit 32 can push the firing unit 31 to move in the first upper accommodating chamber 11, and specifically, the firing unit 31 moves downward under the push of the gas, and in this process, the firing unit 31 cuts off the connection between the two bending portions 44 and the middle section 41, and causes the first bending portion 44a and the second bending portion 44b to bend downward.

[0076] In this embodiment, a power limiter is provided between the power unit 32 and the upper housing 1 to prevent the power unit 32 from rotating, so as to maintain the stability of the power unit 32, thereby ensuring that the excitation type fuse can work normally. Figure 3 , Fig.13 As shown, the upper portion of the upper shell 1 is provided with a fixing groove for installing the power unit 32, and the power limiting portion includes a limiting surface 321 arranged on the power unit 32 and a limiting portion 213 arranged on the fixing groove, wherein the limiting surface 321 is recessed inwardly from the outer side of the power unit 32, and the limiting portion 213 protrudes inwardly from the inner side of the fixing groove. When the power unit 32 is inserted into the fixing groove, the limiting surface 321 abuts against the limiting portion 213, thereby achieving a limiting effect.

[0077] In this embodiment, see Figure 3 As shown, the upper part of the firing part 31 has an impact groove 30 with the notch facing upward, and an impact chamber is formed between the impact groove 30 and the second upper accommodating chamber 12 for providing a space for gas release. At the same time, the impact groove 30 is used to withstand the impact of the gas, thereby driving the firing part 31 to move downward.

[0078] In this embodiment, a sealing mechanism is provided between the side wall of the firing portion 31 and the side wall of the first upper accommodating chamber 11 to improve airtightness, so that under the push of the gas generated by the power portion 32, the firing portion 31 can quickly cut off the conductive portion 4 and protect the circuit. Fig.10 , Fig.11As shown, an annular groove 313 is provided on the upper portion of the firing portion 31 , and the sealing structure includes a sealing ring 314 arranged in the annular groove 313 . The sealing ring 314 is made of elastic material and can be tightly abutted against the side wall of the first upper accommodating cavity 11 to form a seal.

[0079] In this embodiment, the firing portion 31 includes two firing arms 311 extending downward, and the two firing arms 311 are used to cut off the connection between the middle section 41 and the two bent sections 44. The firing portion 31 also includes a pressing portion 312 located between the two firing arms 311. When the trigger device 3 is activated, the pressing portion 312 is used to press against the middle section 41. Fig.10 , Fig.11 As shown, the firing arm 311 extends downward from both sides of the pressing portion 312, and the two firing arms 311 and the pressing portion 312 form an inverted U shape. When the trigger device 3 is activated, the firing arm 311 first presses the conductive portion 4 downward, and cuts off the connection between the middle section 41 and the first conductive segment 42 and the second conductive segment 43. Then, the firing arm 311 drives the two bending portions 44 to bend downward, and the pressing portion 312 presses downward against the middle section 41. After the two bending portions 44 are bent, there is a sufficient insulation distance between the first conductive segment 42 and the second conductive segment 43, and in this state, the pressing portion 312 cooperates with the middle section 41 to limit the displacement of the middle section 41, thereby ensuring good insulation performance.

[0080] In some preferred embodiments, the distance between the two firing arms 311 is slightly greater than the length of the middle section 41, so as to avoid the firing portion 31 being unable to accurately punch and compress the middle section 41 due to the small distance between the two firing arms 311. At the same time, such a configuration can also prevent the middle section 41 from flipping and falling into the lower accommodating chamber 20 when the firing portion 31 moves downward due to the large distance between the two firing arms 311, thus causing a safety hazard.

[0081] In some embodiments, a firing stopper is provided between the firing part 31 and the conductive part 4 to prevent the firing part 31 from rotating, thereby ensuring the accuracy of the cut-off position of the conductive part 4, and preventing the firing part 31 from interfering with the upper shell 1 and the lower shell 2 during the impact and rebound of the firing part 31. In other embodiments, a firing stopper is provided between the firing part 31 and the upper shell 1 to prevent the firing part 31 from rotating, so as to ensure that the firing part 31 can accurately punch the conductive part 4 and prevent interference during the rebound process.

[0082] In this embodiment, the end of each firing arm 311 is provided with two limiting protrusions 3111 and an arm contact portion 3112, see Fig.10 , Fig.11As shown, two limiting protrusions 3111 are arranged on both sides of the arm contact portion 3112. The limiting protrusions 3111 and the side wall of the conductive portion 4 constitute a firing limiting portion. Specifically, before the trigger device 3 is activated, the arm contact portion 3112 abuts against the upper surface of the conductive portion 4, and the two limiting protrusions 3111 are respectively located on both sides of the conductive portion 4 to prevent the firing portion 31 from rotating relative to the conductive portion 4.

[0083] See also Figure 3 , Fig.11 As shown, in the direction toward the lower shell 2, the outer side of the arm contact portion 3112 is provided with an inclined surface extending inwardly, and the setting of the inclined surface reduces the size of the lower end of the arm contact portion 3112, and reduces the contact surface between the arm contact portion 3112 and the conductive portion 4, thereby increasing the pressure applied to the conductive portion 4, and facilitating the punching and cutting of the conductive portion 4. At the same time, when the firing portion 31 continues to move downward, the inclined surfaces on both sides can slide with the first bending portion 44a and the second bending portion 44b, respectively, and drive the first bending portion 44a and the second bending portion 44b to bend toward the side wall of the lower accommodating chamber 20.

[0084] In this embodiment, the pressing portion 312 is provided with a plurality of ridges distributed along a length direction transverse to the conductive portion 4 , so as to enhance the strength of the pressing portion 312 and mainly play the role of breaking the arc.

[0085] In this embodiment, see Fig.12 As shown, the conductive part 4 is in the shape of a long plate, the width of the middle section of the conductive part 4 is narrowed, and the width of the bending part 44 and the middle section 41 is smaller than the width of the first conductive section 42 and the second conductive section 43, so that it can cooperate with the limiting protrusion 3111 on the firing arm 311 to form a firing limiting part. In this embodiment, the two ends of the middle section 41 are respectively provided with sawtooth grooves extending in the width direction at both ends, and the notches of the sawtooth grooves face upwards, so as to facilitate breaking under the stamping of the firing part 31. In this embodiment, the connection between the first conductive section 42 and the first bending part 44a, and the connection between the second conductive section 43 and the second bending part 44b are both provided with semicircular grooves with notches facing downwards, so as to facilitate the bending part 44 to bend downward. In some preferred embodiments, the conductive part 4 is stamped and formed by pure copper or other copper alloy products.

[0086] In this embodiment, the lower shell 2 includes a first lower shell 21 and a second lower shell 22 that are detachably connected, wherein the first lower shell 21 has openings at both ends, the conductive portion 4 passes through the lower shell 2 from the two openings 210, the second lower shell 22 is located below the first lower shell 21, the inner wall of the first lower shell 21 constitutes the side wall of the lower accommodating cavity 20, the top wall of the second lower shell 22 constitutes the bottom wall of the lower accommodating cavity 20, and the arc-extinguishing grid group 5 is fixedly arranged on the top wall of the second lower shell 22.

[0087] In this embodiment, the excitation type fuse further includes a pre-positioning mechanism to position the conductive part 4. Specifically, the pre-positioning mechanism includes a first pre-positioning part arranged on the lower housing 2, and a second pre-positioning part cooperating with the first pre-positioning part is arranged on the conductive part 4. Figure 5 , Figure 8 As shown, the first pre-positioning portion is a positioning column 212 , and the second pre-positioning portion is a hole 45 provided on the conductive portion 4 and adapted to the positioning column 212 .

[0088] In this embodiment, the pre-positioning mechanism includes two groups, the positioning posts 212 are arranged at the two openings 210 of the first lower shell 21 and extend upward, the first conductive segment 42 and the second conductive segment 43 are provided with holes 45, when the conductive part 4 is assembled between the upper shell 1 and the lower shell 2, the positioning posts 212 are correspondingly inserted in the holes 45, so as to position the conductive part 4, and at the same time, the pre-positioning mechanism can also limit the displacement of the conductive part 4, and prevent the conductive part 4 from being displaced during the process of the firing part 31 stamping the conductive part 4. In this embodiment, there is a misalignment between the two holes 45 along the width direction of the conductive part 4, and the two positioning posts 212 are also staggered accordingly, so that it can play a fool-proof effect and prevent errors in the assembly of the conductive part 4.

[0089] In this embodiment, the lower shell 2 is further provided with a buffer portion 211, which is arranged on the side wall of the lower shell 2. Under the drive of the firing portion 31, the bending portion 44 will bend downward and impact the side wall of the lower shell 2. The buffer portion 211 can absorb the kinetic energy generated by the bending portion 44 and produce deformation. Even the buffer portion 211 will break in the process of absorbing the kinetic energy, but it can ensure the integrity of the structure of the lower shell 2 and improve the explosion-proof performance of the lower shell 2. Specifically, the buffer portion 211 includes a buffer wall 2111 and a buffer cavity 2112. The buffer wall 2111 is fixedly connected to the lower shell 2. The buffer wall 2111 constitutes a part of the side wall of the lower accommodating cavity 20. The buffer cavity 2112 is located on the side of the buffer wall 2111 away from the lower accommodating cavity 20. When the bending portion 44 is bent and abuts against the buffer wall 2111, the buffer wall 2111 deforms toward the buffer cavity 2112, thereby offsetting the kinetic energy generated by the bending portion 44. In some preferred embodiments, the thickness of the buffer wall 2111 is 1 / 4 of the thickness of the conductive part 4 .

[0090] See also Figure 5As shown, in this embodiment, the lower part of the buffer wall 2111 is fixedly connected to the lower shell 2, and along the width direction of the conductive part 4, the two sides of the buffer wall 2111 are fixedly connected to the lower shell 2, and the buffer cavity 2112 has an upward mouth. Along the width direction of the conductive part 4, both sides of the buffer wall 2111 are provided with straight grooves extending in the up-down direction, and the side walls of the straight grooves separate the straight grooves themselves from the buffer cavity 2112, and the side parts of the buffer wall 2111 are fixedly connected to the lower shell 2 through the side walls of the straight grooves. Such a configuration allows the two sides of the buffer wall 2111 to deform, improves the deformation performance of the buffer wall 2111, and allows the buffer wall 2111 to better play a buffering role.

[0091] In other embodiments, the buffer wall 2111 includes a buffer fixed end and a buffer free end arranged opposite to the buffer fixed end, and when the bending portion 44 is bent and abuts against the buffer wall 2111, the buffer free end swings toward the buffer cavity 2112 to offset the kinetic energy of the bending portion 44. Specifically, the buffer free end is located above the buffer fixed end, the lower end of the buffer wall 2111 is fixed and the upper end is free, and the buffer wall 2111 can swing toward the buffer cavity 2112 with the buffer fixed end as a fulcrum.

[0092] In this embodiment, the excitation type fuse further includes a fixing seat 6 fixedly connected to the lower housing 2, and the fixing seat 6 is arranged between the first arc extinguishing grid group 5a and the second arc extinguishing grid group 5b. Fig. 9 As shown, each metal plate 51 includes a first supporting wall 512 and a second supporting wall 513, wherein the first supporting wall 512 is fixedly connected to the bottom wall of the lower accommodating cavity 20, and the second supporting wall 513 is fixedly connected to the fixing seat 6. In some preferred embodiments, the metal plate 51 is made of galvanized sheet or other iron alloy products.

[0093] Specifically, see Figures 6 to 9 As shown, the first support wall 512 and the second support wall 513 are perpendicular to each other, and the bottom wall of the lower accommodating chamber 20 and the side wall of the fixing seat 6 are respectively provided with a card slot 70, the first support wall 512 is snapped into the card slot 70 in the lower accommodating chamber 20, and the second support wall 513 is snapped into the card slot 70 of the fixing seat 6. In this embodiment, the extension direction of the card slot 70 on the bottom wall of the lower accommodating chamber 20 is parallel to the length extension direction of the conductive part 4, and the bottom wall of the lower accommodating chamber 20 is also provided with a mounting groove 222 for mounting the fixing seat 6, the extension direction of the mounting groove 222 is perpendicular to the extension direction of the card slot 70, and along the length extension direction of the conductive part 4, the card slot 70 is provided on both sides of the mounting groove 222. Such a configuration makes the assembly of the metal plate 51 simpler.

[0094] In other embodiments, the metal plate 51 and the fixing base 6 are integrally formed, and both are fixedly connected to the second lower shell 22 , or the metal plate 51 , the fixing base 6 and the second lower shell 22 are integrally formed.

[0095] See also Figure 3 , Figure 4 As shown, the top of the fixing seat 6 is used to support the middle section 41. After the bending portion 44 and the middle section 41 are cut off, the middle section 41 is pressed tightly between the pressing portion 312 and the upper portion of the fixing seat 6. In this embodiment, a receiving groove 61 is provided on the top of the fixing seat 6 for filling arc extinguishing material and playing an arc extinguishing role.

[0096] In this embodiment, see Figures 3 to 6 As shown, the metal plates 51 are arranged at intervals along the width direction of the conductive part 4, the slits 52 extend in the vertical direction and along the length direction of the conductive part 4, and the extension direction of the slits 52 matches the movement trajectory of the bending part 44. With such an arrangement, during the process of the bending part 44 bending downward, the slits can continuously capture the arc, thereby achieving the effect of continuous arc extinguishing.

[0097] In this embodiment, a groove 514 for arc diversion is further provided on the top wall of each metal plate 51, and the shape of the groove 514 can be set to be a V-shaped or U-shaped shape with the mouth facing upward. In this embodiment, each metal plate 51 also has an arc-shaped edge 511, see Fig. 9 As shown, the arcuate edge 511 is disposed between the free end of the first supporting wall 512 and the free end of the second supporting wall 513, so that the metal plate 51 is a triangular thin plate. The arcuate edge 511 is disposed so that during the bending of the bending portion 44, the distance between the free end of the bending portion 44 and the metal plate 51 at the corresponding position remains substantially unchanged, thereby preventing the free end of the bending portion 44 from colliding with the metal plate 51.

[0098] When the conductive portion 4 is cut off and the bent portion 44 is bent downward, the arc formed is divided by the groove 514 and the plurality of parallel metal plates 51. When the bent portion 44 continues to bend downward, the arc edge 511 can continuously capture and absorb the arc, so that the metal plate 51 can continue to play the role of arc initiation and maintain a good arc initiation effect. At the same time, the metal plate 51 can also give full play to the performance of the material and improve the utilization rate of the material.

[0099] In this embodiment, the bottom wall of the lower shell 2 is also provided with an airflow channel 221 connected to the outside, and the airflow channel 221 includes a groove 2211 and at least one pressure relief port 2212, the groove 2211 is located at a corresponding position of the lower accommodating chamber 20, and the pressure relief port 2212 is located at a corresponding position of the side wall of the lower shell 2. The provision of the airflow channel 221 improves the exhaust performance of the product under instantaneous high pressure and ensures the safety performance of the excitation type fuse. At the same time, when the bending portion 44 is bent downward, the arc can be blown into and traverse the slit 52 between the metal plates 51 through the provided airflow channel 221, thereby improving the arc extinguishing effect and achieving continuous and stable arc extinguishing.

[0100] See also Figure 6 , Figure 7 As shown, the groove 2211 is arranged in a ring on the outer side of the arc extinguishing grid group 5, and the pressure relief port 2212 includes four pressure relief ports 2212 arranged at intervals along the circumference of the groove 2211. The four pressure relief ports 2212 are all located on the outer side of the groove 2211. The pressure relief ports 2212 are connected to the groove 2211 and to the outer side of the lower shell 2. The gas can enter the groove 2211 through the pressure relief ports 2212 and finally blow the arc into the slit 52.

[0101] In this embodiment, the pressure relief port 2212 and the groove 2211 are not in the same plane. Specifically, along the vertical direction, the groove 2211 is shallower than the pressure relief port 2212, and the bottom of the pressure relief port 2212 is lower than the bottom of the groove 2211, thereby forming a step surface between the pressure relief port 2212 and the groove 2211. When the first lower shell 21 and the second lower shell 22 are fixed to each other, the bottom of the outer wall of the first lower shell 21 is lower than the bottom of the groove 2211, but the bottom of the pressure relief port 2212 is lower than the bottom of the outer wall of the first lower shell 21. In this way, between the first lower shell 21 and the second lower shell 22, the air flow channel 221 extends in a Z-shaped bending trajectory, so that the outer wall of the first lower shell 21 can prevent the arc in the lower accommodating chamber 20 from leaking outward, thereby ensuring the safety of external equipment. At the same time, the outer wall of the first lower shell 21 does not affect the passage of gas, ensuring the normal exhaust function and the blowing function into the lower accommodating chamber 20.

[0102] In summary, the working principle of the excitation type fuse of this embodiment is as follows: the power part 32 generates gas after being triggered, and the gas pushes the firing part 31 to move toward the lower accommodating chamber 20. During this process, the firing arm 311 impacts the conductive part 4, and causes the first bending part 44a to be disconnected from the middle section 41, and the second bending part 44b to be disconnected from the middle section 41. Moreover, driven by the firing arm 311, the first bending part 44a and the second bending part 44b are both bent downward and toward the side wall of the lower accommodating chamber 20. Finally, the first conductive section 42 and the second conductive section 43 are separated from each other, and the pressing part 312 presses the middle section 41 against the fixing seat 6, so that the middle section 41 cannot move. The excitation type fuse of this embodiment can quickly cut off the circuit and ensure the insulation safety after cutting off.

[0103] After the conductive part 4 is cut off, an arc will be formed at the fracture, and the groove 514 on the top wall of the metal plate 51 can divide the arc, and the metal plates 51 arranged in parallel can also divide the arc. In the process of the bending part 44 bending downward, the arc edge 511 and the slit 52 between the metal plates 51 can continuously capture and absorb the arc, and under the action of the airflow channel 221, the arc can also be blown into the slit 52, which not only realizes continuous arc extinguishing, but also has a better arc extinguishing effect, thereby improving the safety performance of the excitation type fuse.

[0104] Example 2

[0105] See also Figures 14 to 18 As shown, the main difference between the excitation type fuse of this embodiment and the embodiment 1 is that: in this embodiment, the multiple metal plates 51 provided in the first arc-extinguishing grid group 5a and the second arc-extinguishing grid group 5b are arranged in parallel along the length extension direction of the conductive part 4, the metal plates 51 extend along the width direction of the conductive part 4, and the slits 52 between two adjacent metal plates 51 extend along the width direction of the conductive part 4 and extend in the vertical direction. Specifically, along the length extension direction of the conductive part 4, the height of each metal plate 51 gradually decreases from the fixing seat 6 to the side wall of the lower accommodating cavity 20, so that each arc-extinguishing grid group forms a discontinuous and incoherent arc edge, so that when the free end of the bending part is bent, the distance from the arc-extinguishing grid group at the corresponding position remains basically unchanged. See Fig.14 As shown, whether it is the first arc-extinguishing grid group 5a or the second arc-extinguishing grid group 5b, in the projection of the vertical plane, the connection line between the tops of the plurality of metal plates 51 is roughly in the shape of a circular arc that is concave downward, so that during the bending of the bending portion 44, the free end of the bending portion 44 will not collide with the metal plate 51, and the metal plate 51 can also continuously capture and absorb the arc. In this embodiment, the metal plate 51 is also provided with a groove 514 for diversion, so that during the bending of the bending portion 44 downward, the arc is divided by the parallel metal plates 51 and the groove 514. However, see Fig.15 , Fig.18 As shown, in this embodiment, along the width extension direction of the conductive part 4, the groove 514 is arranged in the middle of the metal plate 51 and the notch is facing upward. In this way, the parallel metal plates 51 can divide the arc along the length extension direction of the conductive part 4, and the grooves 514 can divide the arc along the width direction of the conductive part 4, which greatly improves the efficiency of arc extinguishing. At the same time, all the grooves 514 form a gap extending along the length direction of the conductive part 4. When the arc is captured by the slit 52, it can also be captured by the gap formed between the grooves 514. In this embodiment, the grooves 514 can also be set to be V-shaped or U-shaped.

[0106] In this embodiment, a slot 70 is also provided on the top wall of the second lower shell 22 (i.e., the bottom wall of the lower shell), and the slot 70 extends along the width direction of the conductive portion 4. The bottom of the metal plate 51 is only engaged in the slot 70 of the second lower shell 22 and is not connected to the fixing seat 6. In this embodiment, the fixing seat 6 includes a supporting portion 62 and a fixing portion 63, wherein the supporting portion 62 is used to support the middle section 41, and the fixing portion 63 is used to be fixedly connected to the metal plate 51. The upper part of the supporting portion 62 is also provided with a receiving groove 61 for filling the arc extinguishing material. See Fig.15 , Fig.17 As shown, the fixing portion 63 is annular and is arranged on the outside of the supporting portion 62. A first clamping groove 631 and a second clamping groove 632 are formed between the fixing portion 63 and the supporting portion 62. Along the length extension direction of the conductive portion 4, the first clamping groove 631 and the second clamping groove 632 are arranged on two different sides of the supporting portion 62, wherein the first arc-extinguishing grid group 5a is inserted in the first clamping groove 631, and the second arc-extinguishing grid group 5b is inserted in the second clamping groove 632. Along the width extension direction of the conductive portion 4, a clamping groove 70 extending in the vertical direction is provided on the side walls of the first clamping groove 631 and the second clamping groove 632. The metal plate 51 inserted in the first clamping groove 631 and the second clamping groove 632 has its two sides clamped in the clamping grooves 70 on both sides.

[0107] In this embodiment, the support portion 62 and the fixing portion 63 can be integrally formed, the arc extinguishing grid group 5 is fixedly connected to the fixing seat 6, and the fixing seat 6 is fixedly connected to the second lower shell 22, or the fixing seat 6 and the arc extinguishing grid group 5 are integrally formed, the integrally formed fixing seat 6 and the arc extinguishing grid group 5 are fixedly connected to the second lower shell 22, or the fixing seat 6, the arc extinguishing grid group 5 and the second lower shell 22 are integrally formed.

[0108] In summary, the excitation type fuse in the above embodiment forms a firing limit portion through the limit protrusion 3111 set on the firing arm 311 and the side wall of the conductive part 4, which is used to prevent the firing part 31 from rotating, and ensure that the firing part 31 can accurately punch and cut the conductive part 4. A buffer portion 211 is also provided on the lower shell 2 to absorb the kinetic energy generated by the impact of the bending portion 44, thereby preventing the bending portion 44 from causing damage to the lower shell 2, thereby improving the explosion-proof performance of the lower shell 2. Whether it is the arc edge 511 in Example 1 or the design of gradually reducing the height of the metal plate 51 in Example 2, both enable the arc extinguishing grid group 5 to continuously extinguish the arc during the process of the bending portion 44 bending downward. The slit between two adjacent metal plates 51 extends in the vertical direction, which can better capture and absorb the arc and better exert the material properties of the metal plate 51. A groove 514 is also provided on the metal plate 51, so that in addition to the metal plate 51 being able to divide the arc, the groove 514 can also divide the arc, thereby improving the arc extinguishing effect. The setting of the airflow channel 221 can not only improve the exhaust performance, but also blow the arc into the slit 52, thereby improving the arc extinguishing effect. The pressure relief port 2212 is staggered with the bottom of the groove 2211, thereby effectively preventing the arc from leaking outward and improving the safety performance.

[0109] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. An excitation type fuse, comprising: Upper shell, A lower housing having a lower accommodating chamber; a trigger device, which is arranged on the upper housing; a conductive portion disposed between the upper housing and the lower housing; before the trigger device is activated, the conductive portion is configured to be conductive; The conductive portion comprises a middle section, a first conductive section, a second conductive section and a bending section, the bending section comprises a first bending section and a second bending section, the first conductive section and the middle section are fixedly connected via the first bending section, and the second conductive section and the middle section are fixedly connected via the second bending section; characterized in that: An arc-extinguishing grid group for arc extinguishing is provided in the lower housing, the arc-extinguishing grid group comprises a first arc-extinguishing grid group and a second arc-extinguishing grid group, each of which comprises a plurality of metal plates spaced apart in the horizontal direction, and a slit distributed in the vertical direction is formed between two adjacent metal plates; the first arc-extinguishing grid group is located below the first bent portion, and the second arc-extinguishing grid group is located below the second bent portion; After the trigger device is activated, the connection between the first bending portion and the middle section is cut off, the connection between the second bending portion and the middle section is cut off, and the first bending portion and the second bending portion are respectively bent toward the lower shell.

2. The excitation type fuse according to claim 1, characterized in that: The lower shell is further provided with a buffer portion, which is arranged on the side wall of the lower shell, and is configured to absorb the kinetic energy of bending of any of the bending portions and generate deformation.

3. The excitation type fuse according to claim 1, characterized in that: Each of the metal plates extends along the length direction of the conductive portion, and each of the metal plates comprises a first supporting wall and a second supporting wall, wherein the first supporting wall is fixedly connected to the bottom wall of the lower accommodating cavity; and / or, The excitation type fuse further comprises a fixing seat fixedly connected to the lower shell, wherein the fixing seat is arranged between the first arc extinguishing grid plate group and the second arc extinguishing grid plate group; the second supporting wall is fixedly connected to the fixing seat.

4. The excitation type fuse according to claim 3, characterized in that: A groove for shunting the electric arc is also formed on the top wall of each metal plate.

5. The excitation type fuse according to claim 1, characterized in that: The bottom wall of the lower shell is also provided with an air flow channel connected to the outside; the air flow channel includes a groove and at least one pressure relief port; the groove is located at a corresponding position of the lower accommodating cavity, and the pressure relief port is located at a corresponding position of the side wall of the lower shell; The pressure relief port and the groove are not in the same plane to prevent the arc from leaking out through the air flow channel.

6. The excitation type fuse according to claim 1, characterized in that: The trigger device includes a firing part and a power part, wherein the power part is arranged above the firing part, and the firing part is arranged above the conductive part; The power unit is used to drive the firing unit to move downward, and the firing unit is used to cut off the conductive unit; the firing unit includes two firing arms extending downward, and the two firing arms are used to cut off the connection between the middle section and the two bending parts respectively. The firing portion between the two firing arms is a pressing portion, and the pressing portion is used to press against the middle section when the trigger device is activated.

7. The excitation type fuse according to claim 6, characterized in that: The end of each firing arm is provided with two limiting protrusions and an arm contact portion. Before the trigger device is activated, the arm contact portion abuts against the upper surface of the conductive portion, and the two limiting protrusions are respectively located on both sides of the conductive portion to prevent the firing portion from rotating relative to the conductive portion.

8. The excitation type fuse according to claim 1, characterized in that: The excitation type fuse also includes a pre-positioning mechanism to position the conductive portion; The pre-positioning mechanism comprises a first pre-positioning portion arranged on the lower housing, and the conductive portion is provided with a second pre-positioning portion cooperating with the first pre-positioning portion; and / or, The first pre-positioning part is a positioning column, and the second pre-positioning part is a hole opened on the conductive part and adapted to the positioning column; the pre-positioning mechanism includes two groups.

9. The excitation type fuse according to claim 6, characterized in that: A firing limiter is provided between the firing part and the conductive part for preventing the firing part from rotating; and / or, A firing limit portion for preventing the firing portion from rotating is provided between the firing portion and the upper shell.

10. The excitation type fuse according to claim 9, characterized in that: Two limiting protrusions are arranged at the end of each firing arm. Before the trigger device is activated, the two limiting protrusions are respectively located on both sides of the conductive part, and the limiting protrusions and the side walls of the conductive part constitute the firing limiting part.

11. The excitation type fuse according to claim 2, characterized in that: The buffer portion includes a buffer wall and a buffer cavity, the buffer wall is fixedly connected to the lower shell body, the buffer wall constitutes a part of the side wall of the lower accommodating cavity, the buffer cavity is located on the side of the buffer wall away from the lower accommodating cavity, and when the bending portion is bent and abuts against the buffer wall, the buffer wall is deformed toward the buffer cavity.

12. The excitation type fuse according to claim 11, characterized in that: The buffer wall includes a buffer fixed end and a buffer free end arranged opposite to the buffer fixed end. When the bending portion is bent and abuts against the buffer wall, the buffer free end swings toward the buffer cavity; the buffer free end is located above the buffer fixed end.

13. The excitation type fuse according to claim 6, characterized in that: The pressing portion includes a plurality of ridges distributed along a length direction transverse to the conductive portion.

14. The excitation type fuse according to claim 1, characterized in that: Each of the metal plates extends along the width direction of the conductive portion, and a plurality of the metal plates are arranged in parallel along the length extension direction of the conductive portion; the excitation type fuse further comprises a fixing seat fixedly connected to the lower housing, the fixing seat being arranged between the first arc extinguishing grid group and the second arc extinguishing grid group, and the height of each of the metal plates gradually decreases from the fixing seat toward the side wall of the lower accommodating cavity, so that each of the arc extinguishing grid groups forms an arc-shaped edge, so that when the free end of the bent portion is bent at the bent portion, the distance from the arc extinguishing grid group at the corresponding position remains substantially unchanged; and / or, The top of each metal plate is provided with a groove for breaking the arc, the bottom wall of the lower shell is provided with a slot, the bottom of the metal plate is snapped into the slot, and the metal plate is not directly connected to the fixing seat.

Images