Explosion-proof and pressure-resistant piezoresistor

Abstract

The application provides an explosion-proof and pressure-resistant piezoresistor, and belongs to the technical field of resistance components; the explosion-proof and pressure-resistant piezoresistor comprises a piezoresistor core, a protective shell and an inner bushing; in the scheme, an annular cavity is arranged in the protective shell, the annular cavity is used for filling an inert medium, through holes and pressure relief holes are arranged on the inner and outer sides of the annular cavity, a pressure-bearing heat-conducting sheet is connected to the position corresponding to the through hole of the inner bushing, a hollow rubber ring is sleeved on the circumferential side of the pressure-bearing heat-conducting sheet, the hollow rubber ring is used for sealing the through hole, a boss is fixedly connected to the position corresponding to the annular cavity of the inner bushing, the boss is inserted into the annular cavity, transition holes and flow guide holes are arranged on the surface of the boss, the through holes and the pressure relief holes are aligned with the transition holes, the piezoresistor core is connected to the inner bushing, and the piezoresistor can prevent secondary fire of small metal particles carried by high-speed jet flow in the process of entering the discharge pressure relief holes.

Description

Technical Field

[0001] This invention relates to the field of resistive components technology, and in particular to an explosion-proof and pressure-resistant varistor. Background Technology

[0002] Varistors (especially zinc oxide varistors) undergo four stages when subjected to overvoltage or repeated surges: performance degradation, heat accumulation, thermal breakdown, and failure. In the performance degradation stage, repeated surges increase micro-defects, leakage current gradually rises, varistor voltage decreases, and residual voltage changes. In the heat accumulation stage, increased leakage current leads to the Joule heating effect, raising the internal temperature of the varistor. Due to the extremely low thermal conductivity of varistor ceramics (only about 1.5% of copper), heat cannot dissipate quickly, resulting in heat accumulation. In the thermal breakdown stage, the temperature continues to rise above the Curie point, the varistor loses its nonlinear characteristics, enters a low-resistance state, and power frequency current surges in. In the failure stage, during the instant of breakdown under continuous load, the ceramic substrate perforates and melts, with the center temperature reaching over 1000℃. The high-temperature arc ignites surrounding flammable materials (epoxy resin encapsulation layers, circuit boards, etc.), causing fires or even explosions.

[0003] The mainstream technical solutions in the existing technology include: filling the shell with flame-retardant materials (such as polyurethane foam, quartz sand, etc.), setting pressure relief holes to prevent excessive internal pressure, using a thermal release mechanism (low-temperature alloy wire + elastic component) to cut off the circuit, and realizing failure alarm through mechanical indicators or micro switches.

[0004] Existing technologies can generally only passively absorb explosive stress and cannot actively suppress combustion conditions. When depressurization occurs, high-temperature gas carrying molten metal particles is ejected, which may ignite surrounding combustibles or damage circuit boards, and cannot solve the problem of secondary fire during the depressurization process. Summary of the Invention

[0005] This invention provides an explosion-proof and pressure-resistant varistor to solve the technical problem that existing technologies can only passively absorb explosion stress and cannot actively suppress combustion conditions. When depressurization occurs, high-temperature gas carrying molten metal particles is ejected, which may ignite surrounding combustibles or damage circuit boards, thus failing to solve the technical problem of secondary fire during the depressurization process.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An explosion-proof and pressure-resistant varistor includes a varistor core and a protective shell. The protective shell has an annular cavity filled with an inert medium. Through holes and pressure relief holes are respectively provided on the inner and outer sides of the annular cavity. An inner bushing has a pressure-bearing heat-conducting sheet connected to the position corresponding to the through hole. A hollow rubber ring is fitted around the circumferential side of the pressure-bearing heat-conducting sheet to seal the through hole. A boss is fixedly connected to the inner bushing at the position corresponding to the annular cavity. The boss is inserted into the annular cavity. A transition hole and a flow guide hole are provided on the surface of the boss. The flow guide hole connects to the annular cavity. The through hole and pressure relief hole are aligned with the transition hole. The varistor core is connected to the inner bushing.

[0007] Optionally, a recessed structure is provided at the position corresponding to the pressure-bearing heat-conducting sheet in the inner bushing, and a connector is provided between the recessed structure and the pressure-bearing heat-conducting sheet. A fracture node is provided on the connector, and the heat generated by the varistor core is transferred to the pressure-bearing heat-conducting sheet through the inner bushing, the recessed structure and the connector.

[0008] Optionally, the surface of the pressure-bearing heat-conducting sheet is provided with an elastic heat-conducting element, and a plurality of the elastic heat-conducting elements abut against the inner end face of the protective shell, wherein the elastic heat-conducting element is "S" shaped.

[0009] Optionally, a medium inlet valve is provided on the outer side of the annular cavity, and a group of the medium inlet valves and a number of through holes and pressure relief holes are symmetrically distributed about the protective shell axis.

[0010] Optionally, an annular groove is provided on the inner wall of the protective housing at the position corresponding to the through hole, and the hollow rubber ring is embedded in the annular groove.

[0011] Optionally, the protective shell is provided with an insertion interface at the position corresponding to the boss, the annular cavity is connected to the insertion interface, the boss is inserted into the insertion interface, and a flexible layer is provided on the surface of the boss.

[0012] Optionally, a second mesh flame-retardant plate is embedded in the sinking structure, and the pressure-bearing heat-conducting sheet is in contact with the surface of the second mesh flame-retardant plate.

[0013] Optionally, the inner liner is provided with an elastic clamping structure and an elastic support structure on the side away from the sinking platform structure, one side of the varistor core overlaps the surface of the elastic support structure, and the elastic clamping structure abuts against the side wall of the varistor core.

[0014] Optionally, a cap is fixedly connected to the opening side of the protective shell, and a mesh flame-retardant plate is embedded in the cap. The other side of the varistor core is in contact with the surface of the mesh flame-retardant plate.

[0015] Optionally, the hollow rubber ring has a "convex" shaped cross-section. The "convex" shaped hollow rubber ring can simultaneously contact the inner wall of the protective shell and the surface of the annular groove. The "convex" shaped hollow rubber ring in contact with the inner wall of the protective shell and the surface of the annular groove is used to seal the annular groove and the through hole. The surface of the hollow rubber ring distributed in the annular groove is provided with micro-holes, and the through hole communicates with the micro-holes.

[0016] The beneficial effects of the above-described technical solution of the present invention are as follows: In the above scheme, by setting a protective shell, an inert medium can be filled into the annular cavity. The inert medium can quickly isolate oxygen. The gas generated by the abnormal operation of the varistor core, mixed with the inert medium, can be discharged through the through hole, transition hole and pressure relief hole. The inert medium can prevent the small metal particles carried by the high-speed jet from igniting again when entering the discharge pressure relief hole.

[0017] By setting an inner liner, it can not only transfer heat, but also seal the through hole through the hollow rubber ring. When the varistor core malfunctions, the through hole can be opened automatically. The through holes in different positions can respectively play the role of discharging inert medium and relieving pressure, preventing the occurrence of ignition points on the inner and outer sides of the protective shell. Attached Figure Description

[0018] Figure 1 This is a perspective view of the explosion-proof and pressure-resistant varistor of the present invention.

[0019] Figure 2 This is an exploded view of the explosion-proof and pressure-resistant varistor of the present invention.

[0020] Figure 3 This is a planar sectional view of the protective casing of the present invention.

[0021] Figure 4 This is a first perspective view of the inner liner of the present invention.

[0022] Figure 5 This is a second perspective view of the inner liner of the present invention.

[0023] Figure 6 This is a side view of the explosion-proof and pressure-resistant varistor of the present invention.

[0024] Figure 7 For the present invention Figure 6 Cross-sectional view of AA.

[0025] Figure 8 This is a planar cross-sectional view of the explosion-proof and pressure-resistant varistor of the present invention.

[0026] Figure 9 For the present invention Figure 8 A magnified view of a portion of point a.

[0027] [Figure Labels] 1. Varistor core; 2. Inner bushing; 21. Elastic clamping structure; 22. Elastic support structure; 23. Recessed platform structure; 24. Boss; 241. Transition hole; 242. Flexible layer; 243. Flow guide hole; 25. Pressure-bearing heat-conducting sheet; 26. Elastic heat-conducting component; 27. Connector; 271. Fracture node; 28. Hollow rubber ring; 281. Micro-hole; 3. Protective shell; 31. Annular cavity; 32. Insertion interface; 33. Annular groove; 34. Through hole; 35. Pressure relief hole; 36. Medium inlet valve; 4. Cap; 5. Mesh flame-retardant plate one; 6. Mesh flame-retardant plate two. Detailed Implementation

[0028] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0029] like Figure 1As shown in Figure 9, an embodiment of the present invention provides an explosion-proof and pressure-resistant varistor, including a varistor core 1 and a protective shell 3. The protective shell 3 has an annular cavity 31 inside, which is filled with an inert medium. The annular cavity 31 has through holes 34 and pressure relief holes 35 on its inner and outer sides, respectively. An inner bushing 2 is provided, and a pressure-bearing heat-conducting sheet 25 is connected to the inner bushing 2 at the position corresponding to the through hole 34. A hollow rubber ring 28 is sleeved on the circumferential side of the pressure-bearing heat-conducting sheet 25, which is used to seal the through hole 34. A boss 24 is fixedly connected to the inner bushing 2 at the position corresponding to the annular cavity 31. The boss 24 is inserted into the annular cavity 31. The surface of the boss 24 is provided with a transition hole 241 and a flow guide hole 243, which is used to connect the annular cavity 31. The through hole 34 and the pressure relief hole 35 are both aligned with the transition hole 241. The varistor core 1 is connected to the inner bushing 2. With the hollow rubber ring 28 surrounding the pressure-bearing heat-conducting plate 25 sealing the transition hole 241 and the inner side of the pressure relief hole 35 by extrusion sealing the through hole 34, the inert medium is compressed and filled into the annular cavity 31 of the protective shell 3. The guide hole 243 on the boss 24 is used to ensure that the inert medium is evenly distributed in the annular cavity 31. The heat generated by the varistor core 1 can not only be transferred to the pressure-bearing heat-conducting plate 25 through the inner bushing 2, but the energy or pressure generated by the abnormal operation of the varistor core 1 can also be applied to the surface of the pressure-bearing heat-conducting plate 25. When the heat or pressure generated by the abnormal operation reaches the threshold and causes the pressure-bearing heat-conducting plate 25 to detach from the inner bushing 2, the through hole 34 is opened due to the detachment of the hollow rubber ring 28. On the one hand, the inert medium inside the annular cavity 31 enters the interior of the protective shell 3 through the through hole 34 to quickly isolate oxygen or prevent fire. On the other hand, the gas generated by the abnormal operation of the varistor core 1... The inert medium can be discharged through the through hole 34, transition hole 241, and pressure relief hole 35. The inert medium can prevent the small metal particles carried by the high-speed jet from igniting again during the process of entering the pressure relief hole 35. In the event of an explosion of the varistor core 1 due to an abnormality, this application addresses the problem of secondary ignition of small metal particles carried by the high-speed jet during the process of discharging the pressure relief hole 35 in existing explosion-proof and pressure-resistant varistors. By setting a protective shell 3, the inert medium can be filled into the annular cavity 31, which can quickly isolate oxygen. By setting an inner liner 2, it can not only transfer heat, but also seal the through hole 34 through the hollow rubber ring 28. When the varistor core 1 malfunctions, the through hole 34 can be automatically opened. The through holes 34 at different positions can respectively serve to discharge the inert medium and relieve pressure, preventing ignition points from appearing on the inner and outer sides of the protective shell. In this embodiment of the invention, the inert medium is a mixture of macromolecular inert gases, including argon, sulfur hexafluoride, carbon dioxide, and nitrogen, with no specific ratio limitation. The inert medium not only accelerates the cooling and extinguishing process of incompletely burned particles and inhibits further dehydrogenation and combustion reactions, but also has insulating properties and good chemical stability.

[0030] As one implementation method in this embodiment, such as Figures 4 to 8 As shown, a recessed structure 23 is provided at the position corresponding to the pressure-bearing heat-conducting plate 25 in the inner bushing 2. A connector 27 is connected between the recessed structure 23 and the pressure-bearing heat-conducting plate 25. A fracture node 271 is provided on the connector 27. The heat generated by the varistor core 1 is transferred to the pressure-bearing heat-conducting plate 25 through the inner bushing 2, the recessed structure 23 and the connector 27.

[0031] In this embodiment of the invention, the number of connectors 27 is multiple sets. Some fracture nodes 271 can be designed as hot-melt forgings, and others can be designed as locally weakened structures. The former can automatically melt and break under high temperature conditions, and the latter can automatically break under high pressure conditions. The purpose is to ensure that the pressure-bearing heat-conducting plate 25 automatically detaches from the position of the through hole 34 under high temperature and high pressure. The above two sets of fracture nodes 271 of different forms will melt and break when the conditions of temperature reaching T1 and pressure reaching P1 are met simultaneously, so as to ensure the stability of the position of the pressure-bearing heat-conducting plate 25 and the sealing of the through hole 34 and prevent the problem of false triggering.

[0032] As one implementation method in this embodiment, such as Figures 4 to 8 As shown, the surface of the pressure-bearing heat-conducting sheet 25 is provided with elastic heat-conducting elements 26. Several elastic heat-conducting elements 26 abut against the inner end face of the protective shell 3. The elastic heat-conducting elements 26 are "S" shaped. The "S" shaped elastic heat-conducting elements 26 not only play the role of axial elastic support, but also weaken the impact force generated by the explosion of the varistor core 1 on the one hand, and transfer the heat of the varistor core 1 to the protective shell 3 on the other hand.

[0033] As one implementation method in this embodiment, such as Figures 7 to 9 As shown, a medium inlet valve 36 is provided on the outside of the annular cavity 31. A group of medium inlet valves 36, as well as several through holes 34 and pressure relief holes 35, are symmetrically distributed about the protective shell 3 axis. The medium inlet valve 36 is a one-way valve structure, which is used to facilitate the user to add inert medium into the annular cavity 31. The medium inlet valves 36 are distributed at the position of the pins or electrodes of the varistor core 1. When the varistor core 1 is installed, the medium inlet valve 36 is in the position directly facing the circuit board, while the pressure relief hole 35 is in the position away from the circuit board. The purpose is to prevent the small metal particles carried by the high-speed jet from damaging the circuit board.

[0034] In this embodiment of the invention, compared to the single-hole design, the annular array distribution of multiple through holes 34 is to prevent the high-speed concentrated injection of gas from aggravating the electric arc or pressure wave, thereby achieving the purpose of both rapid explosion suppression and avoiding the superposition of shock waves. Furthermore, a miniature pressure sensor can be integrated in the annular cavity 31 to actively remind the user of inert gas leakage when the pressure in the annular cavity 31 is lower than the threshold.

[0035] As one implementation method in this embodiment, such as Figures 2 to 9 As shown, an annular groove 33 is provided on the inner wall of the protective shell 3 at the position corresponding to the through hole 34. The hollow rubber ring 28 is embedded in the annular groove 33. The annular groove 33 serves two purposes: firstly, it acts as an axial limit to ensure the relative stability of the circumferential position of the hollow rubber ring 28 under conditions such as severe vibration; secondly, the hollow rubber ring 28 is embedded in the annular groove 33 by compression deformation, so that the hollow rubber ring 28 can be concentrated at the position of the through hole 34. Both are to ensure the sealing stability of the hollow rubber ring 28 to the through hole 34 and prevent leakage of inert gas under normal operating conditions.

[0036] In this embodiment of the invention, the annular groove 33 and the annular cavity 31 are both integrally formed with the protective shell 3.

[0037] As one implementation method in this embodiment, such as Figures 2 to 8 As shown, the protective shell 3 is provided with an insertion interface 32 at the position corresponding to the boss 24. The annular cavity 31 is connected to the insertion interface 32. The boss 24 is inserted into the insertion interface 32. A flexible layer 242 is provided on the surface of the boss 24. The way the boss 24 is inserted into the insertion interface 32 ensures the assembly and disassembly capability of the inner bushing 2. On the other hand, the insertion interface 32 is circumferentially limited by the boss 24. The inert medium will be filled or injected after the inner bushing 2 is assembled. In particular, it prevents the inert medium from leaking from the insertion interface 32. By providing the flexible layer 242, the sealing between the boss 24 and the insertion interface 32 and the inner wall of the annular cavity 31 can be ensured.

[0038] As one implementation method in this embodiment, such as Figure 8As shown, a sunken platform structure 23 houses and embeds a second mesh-type flame retardant board 6. The pressure-bearing heat conducting sheet 25 contacts the surface of the second mesh-type flame retardant board 6. The opening side of the protective housing 3 is fixedly connected with a cap 4. A first mesh-type flame retardant board 5 is embedded in the cap 4. The other side of the varistor core 1 contacts the surface of the first mesh-type flame retardant board 5. The first mesh-type flame retardant board 5 and the second mesh-type flame retardant board 6 have the same structure, both consisting of a mesh outer shell and a flame retardant material filled inside. They not only play a role in ventilation and flame retardance, but also can prevent tiny metal particles carried by the high-speed jet from entering the through hole 34 to a certain extent. The mesh outer shell is made of a heat-conducting material, aiming to transfer the heat of the varistor core 1 to the protective housing 3 and the cap 4 respectively.

[0039] As an implementation manner in this embodiment, as Figures 4 to 8 shown, on the side of the inner lining sleeve 2背离沉台结构23 (away from the sunken platform structure 23), an elastic clamping structure 21 and an elastic supporting structure 22 are provided. One side of the varistor core 1 is lapped on the surface of the elastic supporting structure 22, and the elastic clamping structure 21 abuts against the side wall of the varistor core 1. After the varistor core 1 is installed in the inner lining sleeve 2, the elastic clamping structure 21 and the elastic supporting structure 22 respectively play the roles of circumferential clamping and axial support, thereby weakening the impact force generated instantaneously when the varistor core 1 explodes. At the same time, both of them also play the role of transferring the heat of the varistor core 1.

[0040] As an implementation manner in this embodiment, as Figure 9 shown, the cross-section of the hollow rubber ring 28 is "convex" shaped. The "convex" shaped hollow rubber ring 28 can contact both the inner wall of the protective housing 3 and the surface of the annular groove 33. Micro holes 281 are provided on the surface of the hollow rubber ring 28 distributed in the annular groove 33, and the through hole 34 is communicated with the micro holes 281. The "convex" shaped hollow rubber ring 28 contacting the inner wall of the protective housing 3 and the surface of the annular groove 33 is used to improve the sealing performance of the annular groove 33 and the through hole 34.

[0041] It should be noted that there is a Chinese character "背离" in the original text of item which may be a mistake. I translated it as "away from" according to the context. If this is not what you want, please correct it.In this embodiment of the invention, the hollow rubber ring 28 is made of fluororubber (FKM) or perfluoroether rubber (FFKM) with a temperature resistance of over 250°C, and also possesses aging resistance and softening resistance properties. This is used to reduce the leakage rate of inert gas and ensure the sealing life of the hollow rubber ring 28. The micro-hole 281, also called a micro-breathing hole, and the limiting and positioning settings of the boss 24 and the insertion interface 32 ensure that the micro-breathing hole corresponds only to the through hole 34 during assembly. In this way, even if the gas pressure in the annular cavity 31 increases due to long-term micro-leakage, the micro-breathing hole will not be affected. As the pressure decreases, the gas stored inside the hollow rubber ring 28 remains, but under the pressure of the pressure-bearing heat-conducting plate 25, the two will quickly reach a state of pressure equilibrium. The hollow rubber ring 28, especially the raised feature area, will fit more tightly with the annular groove 33 after inflation and expansion, reducing the risk of leakage. When the hollow rubber ring 28 separates from the annular groove 33, the hollow rubber ring 28 will also discharge inert gas through the micro-hole 281 to participate in suppressing ignition, without causing gas waste, thus solving the problem of high leakage risk in traditional sealing methods.

[0042] The working process of the explosion-proof and pressure-resistant varistor provided by the present invention is as follows: When the heat or pressure generated by the abnormal operation reaches the threshold and causes the pressure-bearing heat-conducting sheet 25 to detach from the inner bushing 2, the through hole 34 is in the open state due to the detachment of the hollow rubber ring 28. On the one hand, the inert medium inside the annular cavity 31 enters the protective shell 3 through the through hole 34 to quickly isolate oxygen or prevent fire. On the other hand, the gas generated by the abnormal operation of the varistor core 1, mixed with the inert medium, can be discharged through the through hole 34, the transition hole 241 and the pressure relief hole 35. The inert medium can prevent the small metal particles carried by the high-speed jet from igniting again during the process of entering the discharge pressure relief hole 35.

[0043] In the above scheme, by setting the protective shell 3, the inert medium can be filled into the annular cavity 31. The inert medium can quickly isolate oxygen. The gas generated by the abnormal operation of the varistor core 1, mixed with the inert medium, can be discharged through the through hole 34, the transition hole 241 and the pressure relief hole 35. The inert medium can prevent the small metal particles carried by the high-speed jet from igniting again during the process of entering the discharge pressure relief hole 35.

[0044] By setting the inner liner 2, it can not only transfer heat, but also seal the through hole 34 through the hollow rubber ring 28. When the varistor core 1 malfunctions, the through hole 34 can be opened automatically. The through holes 34 at different positions can respectively play the role of discharging inert medium and relieving pressure, preventing the occurrence of ignition points on the inner and outer sides of the protective shell.

[0045] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An explosion-proof and pressure-resistant varistor, comprising a varistor core (1), characterized in that, It also includes a protective shell (3), the protective shell (3) having an annular cavity (31) inside, the annular cavity (31) being filled with an inert medium, and the annular cavity (31) having a through hole (34) and a pressure relief hole (35) on its inner and outer sides respectively; The inner sleeve (2) is connected to a pressure-bearing heat-conducting plate (25) at the position corresponding to the through hole (34). The pressure-bearing heat-conducting plate (25) is circumferentially fitted with a hollow rubber ring (28), which is used to seal the through hole (34). The inner sleeve (2) is fixedly connected to a boss (24) at the position corresponding to the annular cavity (31). The boss (24) is inserted into the annular cavity (31). The surface of the boss (24) is provided with a transition hole (241) and a guide hole (243). The guide hole (243) is used to connect the annular cavity (31). The through hole (34) and the pressure relief hole (35) are aligned with the transition hole (241). The varistor core (1) is connected to the inner sleeve (2).

2. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, The inner liner (2) is provided with a recessed platform structure (23) at the position corresponding to the pressure-bearing heat-conducting sheet (25). A connector (27) is connected between the recessed platform structure (23) and the pressure-bearing heat-conducting sheet (25). A fracture node (271) is provided on the connector (27).

3. The explosion-proof and pressure-resistant varistor according to claim 2, characterized in that, The surface of the pressure-bearing heat-conducting sheet (25) is provided with an elastic heat-conducting element (26), and a plurality of the elastic heat-conducting elements (26) abut against the inner end face of the protective shell (3). The elastic heat-conducting element (26) is "S" shaped.

4. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, A medium inlet valve (36) is provided on the outside of the annular cavity (31), and a group of the medium inlet valves (36) and several through holes (34) and pressure relief holes (35) are symmetrically distributed about the protective shell (3).

5. The explosion-proof and pressure-resistant varistor according to claim 4, characterized in that, The inner wall of the protective shell (3) is provided with an annular groove (33) at the position corresponding to the through hole (34), and the hollow rubber ring (28) is embedded in the annular groove (33).

6. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, The protective shell (3) is provided with an insertion interface (32) at the position corresponding to the boss (24). The annular cavity (31) is connected to the insertion interface (32). The boss (24) is inserted into the insertion interface (32). A flexible layer (242) is provided on the surface of the boss (24).

7. The explosion-proof and pressure-resistant varistor according to claim 2, characterized in that, The recessed platform structure (23) contains a mesh flame-retardant plate II (6), and the pressure-bearing heat-conducting sheet (25) is in contact with the surface of the mesh flame-retardant plate II (6).

8. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, The inner sleeve (2) is provided with an elastic clamping structure (21) and an elastic support structure (22) on the side away from the sinking platform structure (23). One side of the varistor core (1) overlaps the surface of the elastic support structure (22), and the elastic clamping structure (21) abuts against the side wall of the varistor core (1).

9. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, The protective shell (3) has a cap (4) fixedly connected to the opening side, and a mesh flame retardant plate (5) is embedded in the cap (4). The other side of the varistor core (1) is in contact with the surface of the mesh flame retardant plate (5).

10. The explosion-proof and pressure-resistant varistor according to claim 1, characterized in that, The hollow rubber ring (28) has a "convex" shaped cross section. The "convex" shaped hollow rubber ring (28) can simultaneously contact the inner wall of the protective shell (3) and the surface of the annular groove (33). The surface of the hollow rubber ring (28) distributed in the annular groove (33) is provided with micro holes (281), and the through hole (34) communicates with the micro holes (281).

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