Circuit breaker and arc chamber assembly thereof

Abstract

The application discloses an arc-extinguishing chamber assembly, which comprises a piston rod, a cylinder body and a piston seat. The outer circumferential surface of the piston rod, the inner wall of the cylinder body and the end surface of the piston seat form a compression cavity. The outer circumferential wall of the piston rod and the inner wall of the piston seat form an expansion cavity which is communicated with a nozzle. The piston seat is provided with a compression hole which is communicated between the expansion cavity and the compression cavity. The compression hole is provided with a one-way compression valve which allows gas to flow from the compression cavity to the expansion cavity. The piston rod is provided with a piston inner cavity which is communicated with the internal gap of a movable arc contact. The side wall of the piston rod is provided with a compensation hole which is communicated between the piston inner cavity and the expansion cavity. The compensation hole is provided with a compensation valve which allows gas to flow from the piston inner cavity to the expansion cavity. The arc-extinguishing chamber assembly can utilize the arc energy generated by the arc contact assembly, so that the operation of the movable mechanism of the circuit breaker is more convenient and labor-saving, and the breaking operation effect of the circuit breaker is optimized. The application further discloses a circuit breaker using the arc-extinguishing chamber assembly.

Description

Technical Field

[0001] This invention relates to the technical field of power system circuit breaker equipment and related accessories, and particularly to an arc-extinguishing chamber assembly. This invention also relates to a circuit breaker using the arc-extinguishing chamber assembly. Background Technology

[0002] Circuit breakers perform both control and protection functions in power systems, making them one of the most critical electrical devices. Correspondingly, the arc-extinguishing chamber, as a core component of the circuit breaker, is used to confine and extinguish electric arcs, ensuring the safe operation of the circuit breaker. Based on their arc-extinguishing principles, circuit breaker arc-extinguishing chambers can be mainly divided into two categories: self-energized arc-extinguishing chambers and compressed air arc-extinguishing chambers.

[0003] Generally, circuit breakers and their arc-extinguishing chambers are also equipped with arc contact assemblies, which work in conjunction with the main contact assemblies to connect, carry, and disconnect normal and fault currents. During the operation of the corresponding switching equipment, the stationary and moving arc contacts of the arc contact assembly disconnect first during opening operations and connect last during closing operations, primarily responsible for extinguishing the arc and preventing equipment damage. The performance of the arc contact assembly directly affects the safety and reliability of the power system.

[0004] During the actual operation of circuit breakers, an electric arc is generated at the contact point between the stationary and moving arc contacts of the arc-extinguishing chamber assembly. However, due to the limitations of the existing arc-extinguishing chamber assembly structure, the arc energy generated at the contact point of the arc-extinguishing chamber assembly currently used in the industry cannot be effectively utilized. Especially during the equipment breaking process, the gas inside the piston rod of the arc-extinguishing chamber is heated by the electric arc generated at the arc-extinguishing chamber assembly, causing the gas pressure inside the piston rod to increase. This high-pressure gas is directly discharged through the gas hole of the piston rod and cannot be utilized, resulting in a certain amount of energy waste. On the other hand, although the existing arc-extinguishing chamber structure includes a compression chamber and a thermal expansion chamber that are matched with the piston rod, the operation of the piston rod and its related actuating mechanism is still not convenient or labor-saving in actual operation.

[0005] In view of this, how to optimize the component structure of the arc-extinguishing chamber to make full use of the arc energy generated at the arc contact assembly, thereby making the operation of the circuit breaker's supporting action mechanism more convenient and labor-saving, and thus optimizing the circuit breaker's breaking operation effect, is an important technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an arc-extinguishing chamber assembly that can fully utilize the arc energy generated at the arc contact assembly, thereby making the operation of the circuit breaker's actuating mechanism more convenient and labor-saving, and thus optimizing the circuit breaker's breaking operation performance. Another purpose of this invention is to provide a circuit breaker using the aforementioned arc-extinguishing chamber assembly.

[0007] To solve the above-mentioned technical problems, the present invention provides an arc-extinguishing chamber assembly disposed in a gas chamber within a circuit breaker housing. The assembly includes a cooperating arc contact assembly and a cylinder assembly. The arc contact assembly includes a stationary arc contact and a moving arc contact that are appropriately matched. The cylinder assembly includes a cylinder body, a piston seat, and a piston rod. The piston seat has a nozzle at one end facing the arc contact assembly, and a throat for the stationary arc contact to pass through in the middle of the nozzle. The outer wall of the piston seat is slidably adapted to the inner wall of the cylinder body. The piston rod passes through the cylinder body and is linked to the piston seat. The moving arc contact is linked to the piston seat. A compressed air chamber is formed between the outer peripheral surface of the piston rod, the inner wall of the cylinder body, and the end face of the piston seat. An expansion chamber communicating with the nozzle is formed between the outer peripheral wall of the piston rod and the inner wall of the piston seat. A compressed air hole communicating between the expansion chamber and the compressed air chamber is passed through the piston seat. A one-way compressed air valve is provided on the compressed air hole, allowing only gas to flow from the compressed air chamber to the expansion chamber.

[0008] The piston rod has an internal piston cavity that communicates with the internal gap of the moving arc contact. A gas supply hole is provided through the side wall of the piston rod, which communicates with the expansion cavity. A gas supply valve is provided on each gas supply hole to allow gas to flow from the internal piston cavity to the expansion cavity.

[0009] Preferably, the piston rod includes a pressurizing section and a depressurizing section coaxially connected in sequence along the axial direction. The pressurizing section is inserted into the cylinder body, and the depressurizing section is located outside the cylinder body. A depressurizing valve is connected between the pressurizing section and the depressurizing section, which only allows gas to flow from the pressurizing section to the depressurizing section, and the opening trigger pressure of the depressurizing valve is greater than the opening trigger pressure of the gas supply valve.

[0010] The air inlet is located on the side wall of the pressurization section, and the side wall of the pressure relief section has a pressure relief hole that connects the piston cavity and the air chamber of the circuit breaker housing.

[0011] Preferably, a heat dissipation and exhaust hole is provided through the side wall of the pressurizing section, and a shield is provided on the end of the cylinder body facing away from the arc contact assembly, and the inner peripheral surface of the shield is in close contact with the outer peripheral surface of the pressurizing section.

[0012] The axial distance between the heat dissipation vent and the piston seat is L, and the axial length of the shield is A, then L > A.

[0013] Preferably, the maximum axial length of the compressed air chamber is B, then L > B, and L < A + B.

[0014] Preferably, the pressure relief valve includes a pressure ring, a hollow valve body, and a valve seat arranged coaxially along the axial direction of the piston rod from one end near the arc contact assembly to the end away from the arc contact assembly. The outer peripheral surface of the hollow valve body is clearance-fitted with the inner peripheral wall of the piston cavity to form an outer valve cavity. The hollow valve body has an inner valve cavity inside. A front valve hole is penetrating through the middle of the pressure ring. The outer valve cavity is connected to the downstream of the inner cavity of the pressurization section through the front valve hole. A rear valve hole is penetrating through the middle of the valve seat and is connected between the inner valve cavity and the inner cavity of the pressure relief section. The rear valve hole is connected to the upstream of the pressure relief hole through the inner cavity of the pressure relief section. An inner valve hole is penetrating through the side wall of the hollow valve body and is connected between the outer valve cavity and the inner valve cavity.

[0015] An elastic pressure relief element is provided between the valve seat and the hollow valve body. The elastic pressure relief element can press the hollow valve body against the pressure ring so that the hollow valve body aligns and seals the front valve hole.

[0016] Preferably, a front limiting ring protrudes from the rear outer peripheral wall of the hollow valve body and extends circumferentially therefrom, and a rear limiting ring protrudes from the rear outer peripheral wall of the valve seat and extends circumferentially therefrom. The outer edges of the front limiting ring and the rear limiting ring are respectively tightly fitted to the inner wall of the piston cavity, so as to form a heat-insulating protection cavity between the rear end face of the front limiting ring, the front end face of the rear limiting ring, the outer peripheral wall of the valve seat, and the inner peripheral wall of the piston cavity, and the elastic pressure relief element is located in the heat-insulating protection cavity.

[0017] Preferably, the elastic pressure relief component is a compression spring coaxially fitted outside the valve seat, with the front end of the compression spring abutting against the rear end face of the front limiting ring and the rear end of the compression spring abutting against the front end face of the rear limiting ring.

[0018] Preferably, the front end of the hollow valve body has a pressure-limiting ring surface extending circumferentially thereon, which can be tightly fitted and abutted against the opening of the front valve hole.

[0019] Preferably, the pressurizing section and the depressurizing section are threadedly connected, and the pressure ring is axially snapped and fixed between the pressurizing section and the depressurizing section.

[0020] The present invention also provides a circuit breaker, including a housing having an internal air chamber, and an arc-extinguishing chamber assembly disposed within the air chamber, wherein the arc-extinguishing chamber assembly is an arc-extinguishing chamber assembly as described in any of the preceding claims.

[0021] Compared to the aforementioned background technology, the arc-extinguishing chamber assembly provided by this invention, during the operation of a circuit breaker using this assembly, utilizes the coordinated operation of various chambers such as the air chamber, expansion chamber, and piston inner chamber, along with matching one-way connecting valve devices such as one-way air valves and replenishing air valves. When an electric arc is generated at the arc contact assembly, the high-temperature and high-pressure gas generated by the arc is introduced into the expansion chamber through the piston inner chamber and the replenishing air valve, thereby pressurizing the expansion chamber and achieving self-pressurization. This converts the arc heat energy into driving pressure to move the piston seat. Thus, it can fully utilize the energy of the electric arc at the arc contact assembly, avoiding energy waste, and also provide supplementary driving force for the circuit breaker's opening operation. This reduces the operational difficulty of the circuit breaker's related action mechanisms in actual operation, making the operation of the circuit breaker's related action mechanisms simpler and less labor-intensive, and improving the circuit breaker's related operational efficiency and breaking operation reliability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A cross-sectional view of the arrangement structure of the arc-extinguishing chamber assembly of a circuit breaker in the gas chamber according to a specific embodiment of the present invention;

[0024] Figure 2 for Figure 1 Cross-sectional view of the arc-extinguishing chamber assembly when it begins to move from the closed state;

[0025] Figure 3 for Figure 2 A cross-sectional view of the arc-extinguishing chamber assembly at the moment when the moving arc contact and the stationary arc contact are about to separate;

[0026] Figure 4 for Figure 2 A cross-sectional view of the arc-extinguishing chamber assembly when the static arc contact has just been withdrawn from the throat of the nozzle.

[0027] Figure 5 for Figure 2 Cross-sectional view of the arc-extinguishing chamber assembly when it is in the fully open position;

[0028] Figure 6 for Figure 2 Enlarged view of a portion of the structure when the pressure relief valve is in a closed, sealed state;

[0029] Figure 7 for Figure 6Enlarged view of a portion of the structure when the pressure relief valve is in the open and conductive state;

[0030] Figure 8 for Figure 2 A schematic diagram showing the component structure of the pressure relief valve.

[0031] in:

[0032] 10-Housing; 101-Gas chamber; 102-Arc contact assembly; 1021-Static arc contact; 1022-Dynamic arc contact; 103-Cylinder assembly;

[0033] 11-Cylinder block; 111-Compression chamber; 112-Shielding cover;

[0034] 12-Piston seat; 121-Nozzle; 122-Throat; 123-Expansion chamber; 124-Compression port; 125-One-way compression valve;

[0035] 13-Piston rod; 130-Piston cavity; 131-Air inlet port; 132-Air inlet valve; 133-Pressure section; 134-Pressure relief section; 135-Pressure relief hole; 136-Stop; 137-Heat dissipation and exhaust port;

[0036] 14-Pressure relief valve; 140-Insulation protection cavity; 141-Pressure ring; 142-Hollow valve body; 1421-Front limit ring; 1422-Pressure limiting ring surface; 143-Valve seat; 1431-Rear limit ring; 144-Outer valve cavity; 145-Inner valve cavity; 146-Front valve hole; 147-Rear valve hole; 148-Inner valve hole; 149-Elastic pressure relief component. Detailed Implementation

[0037] The core of this invention is to provide an arc-extinguishing chamber assembly that can fully utilize the arc energy generated at the arc contact assembly, thereby making the operation of the circuit breaker's actuating mechanism more convenient and labor-saving, and thus optimizing the circuit breaker's breaking operation effect; in addition, a circuit breaker using the above-mentioned arc-extinguishing chamber assembly is also provided.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In the traditional arc-extinguishing chamber structure of circuit breakers, the arc energy generated at the contact assembly cannot be effectively recovered and utilized, resulting in energy waste. Specifically, the pressure of the gas inside the piston rod increases after being heated by the arc, but this high-pressure gas is directly discharged through the vent hole of the piston rod and fails to participate in the subsequent operation process. Furthermore, the operation process of the piston rod and its related actuating mechanism is not convenient and labor-saving, resulting in the circuit breaker's breaking operation effect not being optimized, which affects the safety and reliability of the power system.

[0041] For example, when a circuit breaker in a high-voltage power system performs a tripping operation, the stationary arc contact and the moving arc contact disconnect first, generating an electric arc. This arc heats the gas inside the piston rod, increasing the gas pressure. However, the high-pressure gas is directly discharged through the vent of the piston rod and is not utilized. The operator needs to overcome significant resistance to drive the actuating mechanism, making the operation laborious. As a result, the arc energy generated at the arc contact assembly is continuously wasted, and the actuating mechanism is not operating smoothly due to the additional burden, which in turn affects the circuit breaker's breaking performance.

[0042] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] In specific implementation methods, in conjunction with references Figures 1 to 8 As shown, the arc-extinguishing chamber assembly provided by the present invention is disposed in the gas chamber 101 inside the circuit breaker housing 10, and includes an arc contact assembly 102 and a cylinder assembly 103 that cooperate with each other. The arc contact assembly 102 includes a stationary arc contact 1021 and a moving arc contact 1022 that are adapted to each other. The cylinder assembly 103 includes a cylinder body 11, a piston seat 12 and a piston rod 13. The piston seat 12 has a nozzle 121 at one end facing the arc contact assembly 102, and a throat 122 for the stationary arc contact 1021 to pass through in the middle of the nozzle. The outer wall of the piston seat 12 is slidably adapted to the inner wall of the cylinder body 11. The piston rod 13 passes through the cylinder body 11 and is linked to the piston seat 12. The moving arc contact 1022 is linked to the piston seat 12.

[0044] The outer peripheral surface of the piston rod 13, the inner wall of the cylinder 11, and the end face of the piston seat 12 enclose a compressed air chamber 111. This chamber 111 allows for direct compression of the gas within it during circuit breaker tripping operations, as the piston seat 12 moves under the drive of the piston rod 13, thereby generating high-pressure gas. For example, the end face of the piston seat 12 can form a sealed fit with the inner wall of the cylinder 11, while the outer peripheral surface of the piston rod 13 can form a sliding fit with the inner wall of the piston seat 12. When the piston seat 12 moves away from the arc contact assembly 102, the volume of the compressed air chamber 111 decreases, and the gas is compressed. This structure simplifies the overall design of the arc-extinguishing chamber, eliminating the need for an additional independent compression device to obtain a compressed gas source for arc extinguishing.

[0045] The outer peripheral wall of the piston rod 13 and the inner wall of the piston seat 12 enclose an expansion chamber 123 that communicates with the nozzle 121. This expansion chamber 123 serves as a storage space for high-pressure gas, and its volume design can be adjusted according to arc extinguishing requirements. For example, the volume of the expansion chamber 123 can be designed to store enough gas in a single circuit breaker operation to ensure that the nozzle 121 can continuously and stably eject high-pressure gas when an electric arc is generated. The direct communication between the expansion chamber 123 and the nozzle 121 ensures that the stored high-pressure gas can quickly and effectively act on the arc region, achieving rapid arc extinguishing.

[0046] The piston seat 12 has through-holes 124 that connect the expansion chamber 123 and the compression chamber 111. These through-holes 124 serve as channels for high-pressure gas from the compression chamber 111 to enter the expansion chamber 123. For example, multiple through-holes 124 can be designed and evenly distributed along the circumference of the piston seat 12 to ensure that gas can enter the expansion chamber 123 evenly. The size and number of through-holes 124 can be optimized according to the required gas flow rate and pressure transmission efficiency.

[0047] Correspondingly, the compression port 124 is equipped with a one-way compression valve 125 that allows gas to flow only from the compression chamber 111 to the expansion chamber 123. This one-way compression valve 125 is crucial for achieving unidirectional gas flow. For example, the one-way compression valve 125 can employ a simple spring-loaded check valve structure. When the pressure in the compression chamber 111 is higher than that in the expansion chamber 123, the valve opens, allowing gas to flow into the expansion chamber 123; when the pressure in the expansion chamber 123 is higher than or equal to that in the compression chamber 111, the valve closes, preventing gas backflow. This unidirectional flow mechanism ensures that the expansion chamber 123 can stably maintain a high-pressure state, providing a reliable gas source for subsequent arc blowing operations.

[0048] The piston rod 13 has an internal piston cavity 130 that communicates with the internal gap of the moving arc contact 1022. This internal piston cavity 130 is designed to collect the high-pressure gas generated by the electric arc heating at the moving arc contact 1022. For example, the internal piston cavity 130 can be designed to directly communicate with the cavity or gap inside the moving arc contact 1022, allowing the heat generated by the electric arc at the arc contact assembly 102 to be rapidly transferred to the gas inside the cavity, increasing its pressure. This structure effectively receives and stores arc energy that would otherwise be wasted by direct discharge.

[0049] A gas inlet hole 131 is provided through the side wall of the piston rod 13, connecting the piston cavity 130 and the expansion chamber 123. These gas inlet holes 131 serve as channels for high-pressure gas from the piston cavity 130 to enter the expansion chamber 123. For example, multiple gas inlet holes 131 can be designed and evenly distributed along the side wall of the piston rod 13 to ensure that gas from the piston cavity 130 can be effectively supplied to the expansion chamber 123. The size and position of the gas inlet holes 131 can be optimized based on gas supply efficiency and structural strength.

[0050] Each gas inlet 131 is equipped with a corresponding gas inlet valve 132, which allows gas to flow only from the piston cavity 130 to the expansion chamber 123. This gas inlet valve 132, similar to the one-way pressure valve 125, is crucial for achieving unidirectional gas flow. For example, the gas inlet valve 132 can employ a check valve structure similar to the one-way pressure valve 125. When the pressure in the piston cavity 130 is higher than that in the expansion chamber 123, the valve opens, allowing gas to flow into the expansion chamber 123; when the pressure in the expansion chamber 123 is higher than or equal to that in the piston cavity 130, the valve closes, preventing gas backflow. This unidirectional flow mechanism not only replenishes the high-pressure gas generated by the electric arc heating into the expansion chamber 123, increasing the overall pressure of the expansion chamber 123, but also prevents the backflow of high-pressure gas within the expansion chamber 123, ensuring efficient energy utilization. Typically, the gas inlet valve 132 can be a diaphragm valve, or other types of check valves or one-way valves.

[0051] The following example will provide a more detailed explanation of the above technical solution:

[0052] If the circuit breaker performs a tripping operation in the power system, in the initial stage of tripping, the moving arc contact 1022 of the arc contact assembly 102 begins to separate from the stationary arc contact 1021 under the drive of the operating mechanism. When an arc is generated between the moving arc contact 1022 and the stationary arc contact 1021, the arc extinguishing chamber assembly begins to function.

[0053] Specifically, as the moving arc contact 1022 moves, the piston seat 12 connected to it also moves. The piston seat 12 moves away from the arc contact assembly 102, causing the volume of the compression chamber 111 to decrease. As a result, the gas in the compression chamber 111 is rapidly compressed, and its pressure increases. When the gas pressure in the compression chamber 111 reaches a certain threshold, this high-pressure gas passes through the compression hole 124 on the piston seat 12 and pushes the one-way compression valve 125 located on the compression hole 124 to open. The one-way compression valve 125 only allows gas to flow from the compression chamber 111 to the expansion chamber 123. Therefore, the high-pressure gas is effectively introduced into the expansion chamber 123, thereby increasing the pressure in the expansion chamber 123.

[0054] Meanwhile, the electric arc generated during the separation of the moving arc contact 1022 and the stationary arc contact 1021 heats the gas in the internal gap of the moving arc contact 1022. The pressure of this arc-heated gas increases significantly. Since the piston rod 13 has a piston cavity 130 connected to the internal gap of the moving arc contact 1022, this high-pressure gas is introduced into the piston cavity 130. When the gas pressure in the piston cavity 130 reaches a certain threshold, this high-pressure gas will pass through the gas inlet hole 131 penetrating the side wall of the piston rod 13 and push the gas inlet valve 132 provided on the gas inlet hole 131 to open. The gas inlet valve 132 only allows gas to flow from the piston cavity 130 to the expansion chamber 123. Therefore, the high-pressure gas generated by the arc heating that would otherwise be wasted is also effectively replenished into the expansion chamber 123, further increasing the overall pressure of the expansion chamber 123. When the gas pressure in the expansion chamber 123 reaches the preset arc-extinguishing pressure, the high-pressure gas is ejected at high speed through the piston seat 12 toward the nozzle 121 at one end of the arc contact assembly 102, forming a powerful airflow that directly acts on the arc region between the moving arc contact 1022 and the stationary arc contact 1021. This high-pressure airflow can rapidly cool and disperse the arc, thereby achieving rapid arc extinguishing and ensuring the safe disconnection of the circuit breaker.

[0055] As can be seen from the above examples, the arc-extinguishing chamber assembly of this application, during the circuit breaker tripping operation, not only actively compresses the gas through the movement of the piston seat 12 to generate the pressure required for arc extinguishing, but more importantly, it can effectively recover and utilize the heat energy generated by the electric arc itself. In conventional arc-extinguishing chamber assemblies, when an electric arc is generated, the high-pressure gas heated inside the piston rod 13 is usually directly discharged, resulting in energy waste, and the operating mechanism needs to overcome significant resistance to complete the movement of the piston seat 12. In contrast, this application, by setting the piston inner cavity 130 and the gas replenishment valve 132, replenishes the high-pressure gas generated by the electric arc heating into the expansion chamber 123. This not only increases the arc-extinguishing pressure of the expansion chamber 123 and enhances the arc-blowing effect, but also utilizes the previously wasted energy to assist the movement of the piston seat 12, thereby significantly reducing the work burden of the operating mechanism and making the circuit breaker tripping operation more convenient and labor-saving. This technical concept, which combines mechanical compression with electric arc energy recovery, achieves comprehensive energy utilization, optimizes arc-extinguishing performance, and improves the overall operating efficiency and reliability of the circuit breaker.

[0056] In practical applications, as the electric arc continuously heats the gas in the piston cavity 130, the pressure in the piston cavity 130 will continue to rise. Excessive pressure will not only affect the normal operation of the gas replenishment valve 132, but may also damage the structure of the piston rod 13, posing a safety hazard. If the high-pressure gas is discharged irregularly, it will result in energy waste. It is impossible to reasonably control the pressure in the piston cavity 130, ensure the stability and reliability of the gas replenishment process, and also fail to balance energy utilization and structural safety.

[0057] In this application, the piston rod 13 further includes a pressurizing section 133 and a depressurizing section 134 coaxially connected in sequence along the axial direction. The pressurizing section 133 is inserted into the cylinder body 11, and the depressurizing section 134 is located outside the cylinder body 11. A depressurizing valve 14, which allows gas to flow only from the pressurizing section 133 to the depressurizing section 134, is connected between the pressurizing section 133 and the depressurizing section 134. The activation trigger pressure of the depressurizing valve 14 is greater than the activation trigger pressure of the air supply valve 132. The air supply port 131 is located on the side wall of the pressurizing section 133, and a depressurizing port 135, which is connected to the air chamber 101 of the piston cavity 130 and the circuit breaker housing 10, is penetrating the side wall of the depressurizing section 134.

[0058] The pressurization section 133 is the part of the piston rod 13 inserted inside the cylinder 11, and the depressurization section 134 is the part of the piston rod 13 extending outside the cylinder 11, providing an external passage for gas discharge and connecting to an external operating mechanism. A pressure relief valve 14 is provided between the pressurization section 133 and the depressurization section 134. This pressure relief valve 14 is a one-way valve, which allows gas to flow only from the pressurization section 133 to the depressurization section 134, thereby preventing backflow. The pressure relief valve 14 can be implemented in various forms. For example, it can be a spring-loaded valve that opens against the spring force when the pressure in the pressurization section 133 reaches a preset value; or it can be a diaphragm or piston valve that is driven to open and close by a pressure difference. The activation trigger pressure of the pressure relief valve 14 is set to be greater than that of the air replenishment valve 132. This means that the pressure relief valve 14 requires a higher pressure to open, ensuring that under normal operating conditions, gas preferentially passes through the air replenishment valve 132 into the expansion chamber 123 to pressurize it. The air replenishment port 131 is located on the side wall of the pressurization section 133, and its position is designed inside the cylinder 11, close to the expansion chamber 123, to optimize the gas replenishment path and efficiency. The pressure relief port 135 penetrates the side wall of the pressure relief section 134 and communicates with the air chamber 101 of the circuit breaker housing 10, providing a controlled discharge channel for excessive pressure in the piston cavity 130. In practical applications, a shroud can be arranged on the outer periphery of the pressure relief section 134, and multiple small holes can be arranged on the shroud as heat dissipation holes to disperse the high-temperature gas discharged through the pressure relief hole 135, moderately increase turbulence and discharge resistance, reduce the exhaust impact at the pressure relief hole 135, prevent the high-temperature and high-pressure airflow directly discharged from the pressure relief hole 135 from breaking through or damaging the circuit breaker housing 10, and further optimize the convective heat dissipation capacity at the junction of the pressure relief hole 135 and the air chamber 101.

[0059] The solution proposed in this application achieves precise control of the pressure in the piston cavity 130 and effective utilization of arc energy by segmenting the piston rod 13 and coordinating it with pressure relief valves 14 and gas supply valves 132 with different conduction trigger pressures. During the circuit breaker tripping process, the arc generated at the arc contact assembly 102 heats the gas in the piston cavity 130, causing the pressure in the piston cavity 130 to increase. Since the activation trigger pressure of the pressure relief valve 14 is set to be greater than the activation trigger pressure of the replenishing valve 132, when the pressure in the piston cavity 130 rises to a level sufficient to open the replenishing valve 132 but not yet reaching the activation pressure of the pressure relief valve 14, the high-pressure gas will preferentially replenish the expansion chamber 123 through the replenishing port 131 and the replenishing valve 132 located on the side wall of the pressurizing section 133. This allows the high-pressure gas generated by the electric arc heating to be fully utilized, increasing the pressure in the expansion chamber 123, thereby assisting the tripping operation and reducing the load on the operating mechanism. Only when the pressure in the piston cavity 130 continues to rise, exceeding the activation pressure of the replenishing valve 132 and reaching the activation trigger pressure of the pressure relief valve 14, will the pressure relief valve 14 open, discharging the excess high-pressure gas from the pressurizing section 133 into the pressure relief section 134. Subsequently, this gas is discharged into the gas chamber 101 of the circuit breaker housing 10 through the pressure relief port 135 on the side wall of the pressure relief section 134. This design not only makes full use of the electric arc energy and avoids energy waste, but also effectively prevents damage and malfunctions to the piston rod 13 structure caused by excessive pressure in the piston cavity 130 through timely pressure relief. Thus, it balances energy utilization and operational safety. Especially when interrupting large currents, in order to prevent the electric arc from extinguishing prematurely, the air pressure in the piston cavity 130 will not rise indefinitely. When it reaches the opening air pressure of the pressure relief valve 14, the pressure relief valve 14 will open, and the airflow will be discharged from the piston cavity 130 through the pressure relief hole 135 and discharged into the air chamber 101 of the circuit breaker housing 10. This also realizes the recycling of gas and avoids the negative impact that may be caused by irregular emissions.

[0060] In practical applications, the pressurizing section 133 and the depressurizing section 134 of the piston rod 13 can be assembled by a threaded connection. For example, as shown in the figure, the inner rear end of the pressurizing section 133 is machined with internal threads, and the outer front end of the depressurizing section 134 is machined with external threads. The two are screwed together to form a single unit. The depressurizing valve 14 can be specifically a pre-tightened spring-type check valve. When the pressure inside the pressurizing section 133 reaches a preset value, its valve core overcomes the spring's pre-tightening force and moves towards the depressurizing section 134, thereby opening the gas flow channel. The stiffness or pre-tightening force of this spring is precisely designed to ensure that its activation trigger pressure is higher than that of the gas replenishment valve 132. The gas replenishment port 131 can be a set of radially distributed holes evenly distributed circumferentially along the pressurizing section 133, located in the middle of the pressurizing section 133 and aligned with the expansion chamber 123 to achieve efficient gas replenishment. The pressure relief hole 135 can be one or more radial holes located at the end of the pressure relief section 134 away from the pressurization section 133, ensuring that the gas can be smoothly discharged to the gas chamber 101 of the circuit breaker housing 10.

[0061] More specifically, the pressure relief valve 14 includes a pressure ring 141, a hollow valve body 142, and a valve seat 143 arranged coaxially along the axial direction of the piston rod 13 from one end near the arc contact assembly 102 to the other end away from the arc contact assembly 102. This coaxial arrangement allows the pressure relief valve 14 to be compactly integrated inside the piston rod 13, making full use of the internal space of the piston rod 13 and avoiding additional increases in the radial dimension of the piston rod 13, thereby maintaining the overall compactness of the arc extinguishing chamber assembly.

[0062] The outer peripheral surface of the hollow valve body 142 and the inner peripheral wall of the piston cavity 130 are fitted with a clearance to form an outer valve cavity 144. The hollow valve body 142 has an inner valve cavity 145 inside. A front valve hole 146 passes through the middle of the pressure ring 141. The outer valve cavity 144 is connected to the downstream of the inner cavity of the pressurization section 133 through the front valve hole 146. A rear valve hole 147 passes through the middle of the valve seat 143 and connects the inner cavity of the inner valve cavity 145 and the inner cavity of the pressure relief section 134. The rear valve hole 147 is connected to the upstream of the pressure relief hole 135 through the inner cavity of the pressure relief section 134. An inner valve hole 148 passes through the side wall of the hollow valve body 142 and connects the outer valve cavity 144 and the inner valve cavity 145. The inner valve hole 148 can be designed as multiple small holes evenly distributed around the circumference of the hollow valve body 142 to achieve uniform gas flow. Note that the upstream and downstream mentioned here refer to the arrangement order and orientation based on the airflow direction. All other statements about upstream and downstream in this article can be understood in the same way as those mentioned here, and will not be repeated here.

[0063] An elastic pressure relief element 149 is provided between the valve seat 143 and the hollow valve body 142. The elastic pressure relief element 149 can press the hollow valve body 142 against the pressure ring 141, so that the hollow valve body 142 aligns and seals the front valve hole 146. The elastic pressure relief element 149 is the core control element of the pressure relief valve 14. It maintains the initial position of the hollow valve body 142 through its own elastic force, thereby achieving the sealing of the front valve hole 146. The stiffness of this elastic element determines the conduction trigger pressure of the pressure relief valve 14, which is the key to achieving precise pressure control. The elastic pressure relief element 149 can be a helical compression spring made of stainless steel or other corrosion-resistant and high-temperature-resistant elastic materials; of course, the elastic pressure relief element 149 can also be a wave spring, disc spring, or elastic washer, the material and structural design of which can provide the required preload and elastic restoring force.

[0064] As the initial configuration of the pressure relief valve 14 under normal operating conditions, the preload of the elastic pressure relief component 149 pushes the hollow valve body 142 towards the pressure ring 141, causing the front end face or specific structure of the hollow valve body 142 to come into close contact with the front valve hole 146 on the pressure ring 141. This effectively seals the front valve hole 146, preventing gas from entering the pressure relief valve 14 from the inner cavity of the pressurization section 133. This sealing and fitting structure ensures that gas will not leak prematurely when the internal pressure of the piston rod 13 has not reached the set value, thereby ensuring the accumulation of high-pressure gas in the expansion chamber 123 to assist in arc extinguishing. The front end of the hollow valve body 142 can be designed as conical or flat, forming a tight conical or flat seal with the orifice of the front valve hole 146; of course, an O-ring or elastic sealing gasket can also be provided on the contact surface between the hollow valve body 142 and the pressure ring 141 to enhance the sealing effect.

[0065] Correspondingly, during the circuit breaker tripping operation, when the pressure in the inner cavity of the pressurized section 133 is lower than the conduction trigger pressure of the pressure relief valve 14, the elastic force of the elastic pressure relief component 149 is sufficient to press the hollow valve body 142 tightly against the pressure ring 141, and the front valve hole 146 is effectively blocked by the hollow valve body 142, so that the gas cannot be discharged through the pressure relief valve 14; at this time, the high-pressure gas in the piston inner cavity 130 enters the expansion chamber 123 through the air supply hole 131 and the air supply valve 132, providing high-pressure airflow for arc extinguishing. As the electric arc continues to heat, the pressure inside the pressurizing section 133 continues to rise. Once the pressure inside the pressurizing section 133 reaches and overcomes the preset elastic force of the elastic pressure relief component 149, the hollow valve body 142 will be pushed by the high-pressure gas, overcoming the resistance of the elastic pressure relief component 149 and undergoing axial displacement, thereby separating the hollow valve body 142 from the pressure ring 141 and opening the front valve port 146. At this time, the high-pressure gas inside the pressurizing section 133 enters the outer valve chamber 144 through the front valve port 146, then enters the inner valve chamber 145 through the inner valve port 148 on the side wall of the hollow valve body 142, and finally enters the inner cavity of the pressure relief section 134 through the rear valve port 147 of the valve seat 143, and is discharged to the gas chamber 101 of the circuit breaker housing 10 through the pressure relief port 135, completing the pressure relief and thus realizing precise control of the internal pressure of the piston rod 13. The elastic force setting of the resilient pressure relief component 149 determines the activation trigger pressure of the pressure relief valve 14, ensuring that pressure relief only occurs when the internal pressure exceeds a preset safety threshold. This aligns with the requirement in the aforementioned scheme that the activation trigger pressure of the pressure relief valve 14 is greater than that of the gas supply valve 132, ensuring that during normal arc extinguishing, high-pressure gas is preferentially supplied to the expansion chamber 123 to assist in arc extinguishing, fully utilizing arc energy. Simultaneously, when the internal pressure is too high, the pressure relief valve 14 can open promptly, effectively releasing overpressure gas. Especially when interrupting large currents, the rapid and efficient pressure relief using the pressure relief valve 14 and its associated chambers effectively prevents premature arc extinguishing, ensuring the operational safety of the circuit breaker. This graded chamber and elastic component-controlled pressure relief mechanism enables the arc extinguishing chamber assembly to operate stably and reliably under different interruption conditions.

[0066] In specific assembly applications, the pressure ring 141 can be a disc-shaped structure with a central hole, fixed to the end of the inner cavity of the pressurizing section 133 of the piston rod 13 by interference fit or thread. Especially when the pressurizing section 133 and the pressure relief section 134 are connected by a thread, as shown in the figure, a stop 136 can be arranged at the end of the pressurizing section 133, so that the two axial end faces of the pressure ring 141 abut against the stop 136 surface of the pressurizing section 133 and the front end face of the pressure relief section 134 respectively, thereby achieving axial engagement and locking of the pressure ring 141. The hollow valve body 142 can be a hollow cylinder with an outer diameter slightly smaller than the inner diameter of the piston inner cavity 130, forming an annular outer valve cavity 144. Four inner valve holes 148 can be evenly distributed on the side wall of the hollow valve body 142, arranged radially. The valve seat 143 can be a cylinder with a central through hole, whose outer diameter is tightly fitted with or axially abuts the inner diameter of the piston cavity 130, and is adapted to the hollow valve body 142 through the elastic pressure relief element 149.

[0067] Furthermore, a front limiting ring 1421 extending circumferentially is provided on the rear outer peripheral wall of the hollow valve body 142, and a rear limiting ring 1431 extending circumferentially is provided on the rear outer peripheral wall of the valve seat 143. The outer edges of the front limiting ring 1421 and the rear limiting ring 1431 are respectively tightly fitted to the inner wall of the piston cavity 130, so as to form a heat insulation protection cavity 140 between the rear end face of the front limiting ring 1421, the front end face of the rear limiting ring 1431, the outer peripheral wall of the valve seat 143, and the inner peripheral wall of the piston cavity 130. The elastic pressure relief member 149 is located in the heat insulation protection cavity 140.

[0068] The front limiting ring 1421 can be integrally molded with the hollow valve body 142, for example, through injection molding, casting, or machining; or it can be a separate structure, fixed to the hollow valve body 142 by welding, threaded connection, or snap-fit. Its main function is to cooperate with the inner wall of the piston cavity 130 to form part of the heat insulation protection cavity 140 and to limit the elastic pressure relief element 149. Similar to the front limiting ring 1421, the rear limiting ring 1431 can also be integrally molded or a separate structure. For example, it can be an integral flange structure with the valve seat 143, or a separate annular element can be fixed to the valve seat 143 by press fitting, bonding, etc. Its function is to cooperate with the inner wall of the piston cavity 130 to jointly enclose the heat insulation protection cavity 140 and to provide another end limit for the elastic pressure relief element 149. The component structure of the heat insulation protection cavity 140 cleverly utilizes the existing structure of the hollow valve body 142, valve seat 143 and piston inner cavity 130, without the need to introduce additional independent heat insulation components, thereby further simplifying the supporting components of the arc-extinguishing chamber assembly, making the overall assembly structure of the arc-extinguishing chamber assembly more compact and sophisticated.

[0069] The heat insulation protection chamber 140 is a relatively enclosed space whose main function is to isolate high-temperature gas and provide a relatively low-temperature environment for the internal elastic pressure relief component 149. The formation of this chamber depends on the precise matching and tight fit of the above-mentioned components to ensure that it is effectively isolated from the gas in the mainstream area of ​​the piston cavity 130. This protects the elastic pressure relief component 149 located in the heat insulation protection chamber 140 from the influence of the external high-temperature and high-pressure environment 141, prevents the elastic pressure relief component 149 from being burned by high temperature or structural failure, and extends its service life. This further ensures the operating accuracy and working reliability of the pressure relief valve 14 and makes the overall structure of the pressure relief valve 14 more durable.

[0070] Based on this, the elastic pressure relief component 149 can be a compression spring coaxially fitted outside the valve seat 143. The front end of the compression spring abuts against the rear end face of the front limiting ring 1421, and the rear end of the compression spring abuts against the front end face of the rear limiting ring 1431. The compression spring has a simple structure, is easy to process and procure, and can appropriately reduce the overall cost of the arc-extinguishing chamber assembly. At the same time, the elastic restoring force of the compression spring is uniform and reliable, which can effectively ensure the opening and closing action effect and working efficiency of the pressure relief valve 14. In addition, the spiral extension structure of the compression spring itself has high compatibility with the structure of the valve seat 143 and the hollow valve body 142, which can further utilize the assembly space of the pressure relief valve 14, making the structure of the pressure relief valve 14 and its supporting components more compact and regular.

[0071] On the other hand, the front end of the hollow valve body 142 has a pressure-limiting ring 141 extending circumferentially. Under the elastic clamping force applied to the hollow valve body 142 by the elastic pressure relief member 149, the pressure-limiting ring 141 can be tightly fitted and abutted against the opening of the front valve hole 146, thereby ensuring the sealing airtightness of the pressure relief valve 14 under normal conditions. The pressure-limiting ring 141 can be an annular conical surface arranged obliquely along the axial direction, or an annular chamfered surface or arc surface with a moderately smooth transition.

[0072] In addition, a heat dissipation and exhaust hole 137 is provided through the side wall of the pressurization section 133, and a shield 112 is provided protruding from one end of the cylinder body 11 facing away from the arc contact assembly 102. The inner circumferential surface of the shield 112 is in close contact with the outer circumferential surface of the pressurization section 133. The heat dissipation and exhaust hole 137 can be designed as multiple circular or elliptical holes, evenly distributed along the circumferential or axial direction of the side wall of the pressurization section 133 to achieve efficient heat dissipation and exhaust. In addition, the heat dissipation and exhaust hole 137 can also be a slit-like opening or a ventilated area made of porous material to adapt to different design requirements and manufacturing processes. The shield 112 is a protruding structure provided at one end of the cylinder body 11 facing away from the arc contact assembly 102. Its function is to shield the heat dissipation and exhaust hole 137 under specific working conditions, and at the same time, to protect the inside of the cylinder body 11 and prevent external impurities from entering. The shield 112 can be integrally formed with the cylinder body 11, for example, designed as an annular flange or a cylindrical coaxial extension, or it can be manufactured separately and fixed to the cylinder body 11 by means of threads, welding or snaps. The inner circumferential surface of the shield 112 fits tightly with the outer circumferential surface of the pressurization section 133 to provide a good sealing effect, prevent external impurities from entering the cylinder body 11, and effectively seal the heat dissipation and exhaust port 137 as needed during the sliding of the piston rod 13.

[0073] The axial distance between the heat dissipation exhaust port 137 and the piston seat 12 is L, and the axial length of the shield 112 is A, so L > A. This L > A dimension setting ensures that after the piston rod 13 moves backward and extends a certain distance, the heat dissipation exhaust port 137 can be exposed from the shield 112, thereby achieving on-demand heat dissipation and exhaust. Based on this, the maximum axial length of the compression chamber 111 is B, so L > B, and L < A + B. Based on this dimension design, it is possible that when the piston rod 13 is at its maximum forward stroke, the heat dissipation exhaust port 137 will not be connected to the compression chamber 111, and when the piston rod 13 is at its maximum backward stroke, the heat dissipation exhaust port 137 will definitely extend out of the shield 112 and thus be connected to the inner cavity of the pressure relief section 134.

[0074] Specifically, in the initial stage of the piston rod 13 tripping action, such as Figure 2 and Figure 3 As shown, the heat dissipation exhaust vent 137 is tightly sealed by the inner circumferential surface of the shield 112, thereby ensuring the sealing of the air chamber 111 during the compression and pressurization stage, preventing gas leakage, and ensuring that the air chamber 111 can work normally and achieve the expected pressurization effect; as the tripping action continues, as Figure 4 and Figure 5As shown, especially during prolonged arcing conditions, as the piston rod 13 slides further backward, the heat dissipation vent 137 extends out of the shield 112 along with the pressurized section 133, no longer blocked by the shield 112. Once the heat dissipation vent 137 is exposed, excess heat and high-pressure gas accumulated inside the pressurized section 133 and the cylinder 11 can be effectively and promptly discharged through the heat dissipation vent 137, preventing heat buildup inside the cylinder 11 that could lead to overheating and aging of components, and also preventing abnormal increases in internal pressure. This design cleverly balances the requirements of the arc-extinguishing chamber assembly for sealing, compression, and heat dissipation at different operating stages, making the entire arc-extinguishing process more stable and reliable.

[0075] It is easy to understand that the "front" and "rear" mentioned in this scheme are relative to the conventional arrangement of the arc-extinguishing chamber assembly. Taking the piston rod 13 in the figure as an example, during the closing operation, the piston rod 13 moves forward to make the moving arc contact 1022 contact and match with the stationary arc contact 1021; during the opening operation, the piston rod 13 moves backward to separate the moving arc contact 1022 from the stationary arc contact 1021. The arrangement of all related components, especially the axially matching components, involved in this scheme and the figure can be understood with reference to this. In particular, for the supporting components of the cylinder assembly, the end facing / close to the arc contact assembly 102 is the front end, and the end facing away / away from the arc contact assembly 102 is the rear end. The relevant descriptions of the front and rear orientations in other parts of this application can be understood with reference to this, and will not be repeated here.

[0076] In a specific embodiment, the circuit breaker provided by the present invention includes a housing 10 with an internal air chamber 101, and an arc-extinguishing chamber assembly disposed within the air chamber 101, which is the arc-extinguishing chamber assembly as described above. The arc-extinguishing chamber assembly of this circuit breaker can fully utilize the arc energy generated at the arc contact assembly 102, thereby making the operation of the circuit breaker's actuating mechanism more convenient and labor-saving, and thus optimizing the circuit breaker's breaking operation effect.

[0077] In summary, the arc-extinguishing chamber assembly provided in this invention utilizes the coordinated operation of various chambers, including the air chamber, expansion chamber, and piston inner chamber, along with a matching one-way connecting valve device such as a one-way air valve and a replenishing air valve. When an electric arc is generated at the arc contact assembly, the high-temperature and high-pressure gas generated by the arc is introduced into the expansion chamber through the piston inner chamber and the replenishing air valve, thereby pressurizing the expansion chamber and achieving self-pressurization. This converts the arc heat energy into driving pressure to move the piston seat. Thus, it can fully utilize the energy of the electric arc at the arc contact assembly, avoiding energy waste, and also provide a supplementary driving force for the circuit breaker's opening operation. This reduces the operational difficulty of the circuit breaker's related action mechanisms in actual operation, making the operation of the circuit breaker's related action mechanisms simpler and less labor-intensive, and improving the circuit breaker's related operational efficiency and the reliability of its opening operation.

[0078] The present invention also provides a circuit breaker in which the arc-extinguishing chamber assembly can make full use of the arc energy generated at the arc contact assembly, thereby making the operation of the circuit breaker's actuating mechanism more convenient and labor-saving, and thus optimizing the circuit breaker's opening and closing operation effect.

[0079] The arc-extinguishing chamber assembly and the circuit breaker using the arc-extinguishing chamber assembly provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An arc-extinguishing chamber assembly, disposed in a gas chamber within a circuit breaker housing, comprising a cooperating arc contact assembly and a cylinder assembly, the arc contact assembly including a stationary arc contact and a moving arc contact that are appropriately matched, the cylinder assembly including a cylinder body, a piston seat, and a piston rod, the piston seat having a nozzle at one end facing the arc contact assembly, the nozzle having a throat in the middle for the stationary arc contact to pass through, the outer wall of the piston seat slidingly adapted to the inner wall of the cylinder body, the piston rod penetrating the cylinder body and being linkedly connected to the piston seat, and the moving arc contact being linkedly connected to the piston seat; characterized in that... The outer peripheral surface of the piston rod, the inner wall of the cylinder, and the end face of the piston seat form a compressed air chamber. The outer peripheral wall of the piston rod and the inner wall of the piston seat form an expansion chamber that communicates with the nozzle. A compressed air hole is provided through the piston seat, communicating between the expansion chamber and the compressed air chamber. A one-way compressed air valve is provided on the compressed air hole, which only allows gas to flow from the compressed air chamber to the expansion chamber. The piston rod has an internal piston cavity that communicates with the internal gap of the moving arc contact. A gas supply hole is provided through the side wall of the piston rod, which communicates with the expansion cavity. A gas supply valve is provided on each gas supply hole to allow gas to flow from the internal piston cavity to the expansion cavity.

2. The arc-extinguishing chamber assembly as described in claim 1, characterized in that, The piston rod includes a pressurizing section and a depressurizing section coaxially connected in sequence along the axial direction. The pressurizing section is inserted into the cylinder body, and the depressurizing section is located outside the cylinder body. A depressurizing valve is connected between the pressurizing section and the depressurizing section, which only allows gas to flow from the pressurizing section to the depressurizing section, and the opening trigger pressure of the depressurizing valve is greater than the opening trigger pressure of the gas supply valve. The air inlet is located on the side wall of the pressurization section, and the side wall of the pressure relief section has a pressure relief hole that connects the piston cavity and the air chamber of the circuit breaker housing.

3. The arc-extinguishing chamber assembly as described in claim 2, characterized in that, The side wall of the pressurization section has heat dissipation and exhaust holes, and a shield is provided on the end of the cylinder body facing away from the arc contact assembly. The inner circumferential surface of the shield is in close contact with the outer circumferential surface of the pressurization section. The axial distance between the heat dissipation vent and the piston seat is L, and the axial length of the shield is A, then L > A.

4. The arc-extinguishing chamber assembly as described in claim 3, characterized in that, If the maximum axial length of the compressed air chamber is B, then L > B, and L < A + B.

5. The arc-extinguishing chamber assembly as described in claim 2, characterized in that, The pressure relief valve includes a pressure ring, a hollow valve body, and a valve seat arranged coaxially along the axial direction of the piston rod from one end near the arc contact assembly to the end away from the arc contact assembly. The outer peripheral surface of the hollow valve body is clearance-fitted with the inner peripheral wall of the piston cavity to form an outer valve cavity. The hollow valve body has an inner valve cavity inside. A front valve hole is penetrating through the middle of the pressure ring. The outer valve cavity is connected to the downstream of the inner cavity of the pressurization section through the front valve hole. A rear valve hole is penetrating through the middle of the valve seat and is connected between the inner valve cavity and the inner cavity of the pressure relief section. The rear valve hole is connected to the upstream of the pressure relief hole through the inner cavity of the pressure relief section. An inner valve hole is penetrating through the side wall of the hollow valve body and is connected between the outer valve cavity and the inner valve cavity. An elastic pressure relief element is provided between the valve seat and the hollow valve body. The elastic pressure relief element can press the hollow valve body against the pressure ring so that the hollow valve body aligns and seals the front valve hole.

6. The arc-extinguishing chamber assembly as described in claim 5, characterized in that, A front limiting ring protrudes from the rear outer peripheral wall of the hollow valve body and extends circumferentially therefrom. A rear limiting ring protrudes from the rear outer peripheral wall of the valve seat and extends circumferentially therefrom. The outer edges of the front limiting ring and the rear limiting ring are respectively tightly fitted to the inner wall of the piston cavity to form a heat-insulating protection cavity between the rear end face of the front limiting ring, the front end face of the rear limiting ring, the outer peripheral wall of the valve seat, and the inner peripheral wall of the piston cavity. The elastic pressure relief element is located in the heat-insulating protection cavity.

7. The arc-extinguishing chamber assembly as described in claim 6, characterized in that, The elastic pressure relief component is a compression spring coaxially mounted on the outside of the valve seat. The front end of the compression spring abuts against the rear end face of the front limiting ring, and the rear end of the compression spring abuts against the front end face of the rear limiting ring.

8. The arc-extinguishing chamber assembly as described in claim 5, characterized in that, The front end of the hollow valve body has a pressure-limiting ring surface that extends circumferentially, and the pressure-limiting ring surface can fit tightly against and abut against the opening of the front valve hole.

9. The arc-extinguishing chamber assembly as described in claim 5, characterized in that, The pressurizing section and the depressurizing section are threaded together, and the pressure ring is axially snapped and fixed between the pressurizing section and the depressurizing section.

10. A circuit breaker, comprising a housing having an internal air chamber, and an arc-extinguishing chamber assembly disposed within the air chamber, characterized in that, The arc-extinguishing chamber assembly is the arc-extinguishing chamber assembly as described in any one of claims 1 to 9.

Images