A DC contactor arc extinguishing system

Abstract

The present invention relates to an arc extinguishing system for a DC contactor, and belongs to the technical field of DC contactors. The system comprises a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a shell; the arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and an airflow guide; a partition is provided below the moving contact in the upper cavity of the DC contactor, and an arc extinguishing chamber and an airflow guide are provided on the partition, and the arc extinguishing chamber is provided at the outer periphery of the relative motion area between the moving contact and the static contact of the DC contactor; an arc extinguishing cavity extending from the upper cavity to the lower cavity is provided between the outer periphery of the metal cup of the shell and the electromagnetic system. The present invention arranges arc extinguishing grids and airflow guides in a limited cavity space, improves the arc extinguishing ability, realizes the airway circulation and diffusion of high-temperature arc-burning gas in the upper and lower cavities of the contactor, strengthens the arc cooling effect, avoids the pollution of the main cavity of the DC contactor, further improves the arc extinguishing ability, and ensures the safe use of the DC contactor.

Description

Technical Field

[0001] The invention relates to an arc extinguishing system for a DC contactor, belonging to the technical field of DC contactors. Background Art

[0002] A DC contactor is a contactor used in a DC circuit, mainly used to control a DC circuit (main circuit, control circuit, excitation circuit, etc.). A DC contactor needs to frequently open and close large load currents, so it must have a strong arc extinguishing capability, a flexible contact system, and a reliable electromagnetic system.

[0003] In the field of new energy applications, for example, pure electric vehicles usually use high-voltage DC contactors to connect and disconnect the power battery system, and can disconnect the high-voltage battery system in the event of an accident. The electrical contacts will discharge and generate arcs during the process of connection and disconnection. The generation of arcs will delay the circuit breaking. Higher arc energy may even burn the electrical contacts, causing them to melt and weld. In addition, since the current DC contactors are sealed, in severe cases, they may cause the switch electrical appliances to catch fire and explode.

[0004] In the prior art, in order to make the DC contactor product small in size and high in operating load, high-voltage DC contactors usually use sealed gas-filled external magnetic fields to stretch the metal phase arc laterally, and the arc quickly cools, recombines and deionizes in the arc extinguishing medium. Under normal circumstances, the above technical means have limited arc extinguishing space, long arc burning time, and the metal particles and carbonized impurities generated during the arc extinguishing process accumulate inside the arc extinguishing cavity, polluting the cavity, which easily leads to a decrease in insulation capacity after a certain degree of electrical life. For example: At present, manufacturers such as Tyco, Panasonic, and LS in the market all use magnetic blowout arc extinguishing technology, and most of these arc extinguishing solutions have current polarity requirements. When the current polarity is reversed, the life capacity drops suddenly, and even explodes.

[0005] The internal structure of the common high-voltage DC contactor is shown in the following figure. Figure 1 , 2 As shown. In the existing patent literature, Chinese invention patents CN102074387A and CN104412353A also disclose two typical structural arrangements of high-voltage DC contactors. The disadvantage of this design is that the contact arc extinguishing system does not fully utilize the upper cavity volume of the contactor ( Figure 2It is a side view. The cavities on both sides of the moving contact bridge are isolated from the contact arc extinguishing system. The cavity is not effectively utilized). The arc extinguishing capacity is limited. At the same time, it is difficult to continue to improve the arc extinguishing ability and shorten the arc burning time by relying solely on the technical means of permanent magnet magnetic blowing arc extinguishing under gas atmosphere conditions. In addition, the metal particles and carbonized impurities generated during the arc extinguishing process accumulate inside the arc extinguishing cavity, polluting the cavity, which can easily lead to a decrease in insulation capacity after a certain degree of electrical life. The arc extinguishing chamber adopts a square closed cavity, and the arc extinguishing channel is long and narrow. The high-temperature arc cannot flow and circulate. Under higher levels of disconnection, it is easy for the arc to be unable to dissipate and cool quickly. The excessive pressure in the inner cavity causes the product to explode. In addition, this type of contactor has strict requirements on the current polarity, so the environmental applicability is greatly reduced.

[0006] In the existing new energy application field, the power battery system is generally 400VDC, which may be greatly increased in the future. Therefore, the high-voltage DC contactor needs a stronger arc extinguishing ability, which can safely open and close relatively large currents and avoid damage to the contacts in the contactor caused by welding and excessive arcs. Therefore, this technical field urgently needs to use arc extinguishing devices in DC contactors to achieve efficient and reliable arc extinguishing effects. Summary of the invention

[0007] The purpose of the present invention is to solve the technical problem of achieving efficient and reliable arc extinguishing in a DC contactor.

[0008] In order to achieve the purpose of solving the above-mentioned problems, the technical solution adopted by the present invention is to provide a DC contactor arc extinguishing system, the DC contactor includes a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a shell; the electromagnetic system includes a central axis, a static iron core, a moving iron core, a skeleton coil, a metal cup and a yoke; the arc extinguishing system includes an arc extinguishing chamber, an arc extinguishing cavity and an airflow guide; a partition is provided below the moving contact in the upper cavity of the DC contactor, and an arc extinguishing chamber is provided on the partition, and the arc extinguishing chamber is provided on the outer periphery of the relative motion area of ​​the moving contact and the static contact of the DC contactor; an arc extinguishing cavity extending from the upper cavity of the DC contactor to the lower cavity is provided between the shell and the outer periphery of the metal cup of the electromagnetic system; an airflow guide is provided on the partition.

[0009] Preferably, the arc extinguishing chamber includes an arc extinguishing grid and an arc isolating plate 2. The arc extinguishing chamber is provided with two arc isolating plates 2 on both sides of the relative movement area between the moving contact and the static contact of the DC contactor. The arc isolating plates 2 are arranged on the partition, and the plate surface of the arc isolating plates 2 is parallel to the center axis of the moving contact of the DC contactor; a sheet-shaped arc extinguishing grid is arranged between the two arc isolating plates 2, perpendicular to the arc isolating plates 2 and parallel to each other; the arc extinguishing chamber is provided with an opening on one side relative to the moving contact of the DC contactor, and the arc extinguishing chamber is provided with an opening on the other side relative to the moving contact of the DC contactor.

[0010] Preferably, the cross section of the shell perpendicular to the central axis is set to a bowtie-shaped structure with a small middle cross section and gradually larger cross sections on both sides. The contact system is arranged in the middle part of the cavity with a smaller cross section, and the arc extinguishing chamber is arranged in the fan-shaped parts on both sides of the cavity.

[0011] Preferably, the grid of the arc extinguishing chamber is provided with an arc striking groove.

[0012] Preferably, the airflow guide comprises a bottom plate, an arc isolation plate and a partition; a partition is provided below the moving contact in the upper cavity of the DC contactor, the bottom plate is provided on the partition, and the arc isolation plate and the partition are provided on the bottom plate; the partition is provided at the opening on the other side of the arc extinguishing chamber relative to the contact system of the DC contactor; two arc isolation plates symmetrically provided on both sides of the arc extinguishing chamber adjacent to the moving contact movement area and centered on the partition include arc isolation walls and air guide plates, and the arc isolation walls provided on both sides of the arc extinguishing chamber extend toward the partition and are provided with air guide plates.

[0013] Preferably, the airflow guide comprises a bottom plate, an arc isolation plate, a separator and an arc-blocking air guide plate; a separator is provided below the moving contact in the upper cavity of the DC contactor, and a bottom plate is provided on the separator, and an arc isolation plate, a separator and an arc-blocking air guide plate are provided on the bottom plate; the separator is provided at the opening of the arc extinguishing chamber on the other side relative to the contact system of the DC contactor; two arc isolation plates symmetrically provided on both sides of the arc extinguishing chamber adjacent to the moving contact movement area and symmetrically with the separator as the center include arc isolation walls and air guide plates, and the arc isolation walls provided on both sides of the arc extinguishing chamber extend toward the separator and are provided with air guide plates; the separator is provided with arc-blocking air guide plates extending to both sides, and the arc-blocking air guide plates include an arc-blocking portion, an air guide portion and a sharpened end portion, the separator is extended to both sides with an arc-blocking portion, the arc-blocking portion is bent and extended to be provided with an air guide portion surrounding the air guide plate, and the end of the air guide portion is provided with a sharpened end portion; the bent connection between the air guide portion and the arc-blocking portion corresponds to the air guide plate.

[0014] Preferably, an air outlet 1 is provided between the air guide plate of the airflow guide and the shell wall of the shell; an air outlet 2 is provided between the arc isolation wall and the shell wall of the shell; and an air storage space 1 is provided between the air outlet 1 and the air outlet 2.

[0015] Preferably, an air outlet three is provided between the air guide plate of the airflow guide and the arc blocking portion; an air outlet four is provided between the arc isolation wall and the air guide portion; an air outlet five is provided between the sharpened end and the shell wall of the shell; an air storage space two is provided between air outlet three and air outlet four, and an air storage space three is provided between air outlet five and the shell wall of the shell.

[0016] Preferably, the arc-extinguishing grid is made of cold-rolled steel plate, copper plate, meta-aromatic polyphthalamide fiber Nomex profile or ceramic.

[0017] Preferably, a U-shaped structural member bracket is provided on the moving contact, and the bracket is made of magnetic conductive material.

[0018] Preferably, an arc isolation plate 3 is provided at the top end of the moving contact, and the arc isolation plate 3 is provided at the middle position of the top end of the moving contact, so as to separate the two contact points of the moving contact and the static contact into two spaces.

[0019] High temperature and high pressure gas always moves towards low temperature and low pressure environment. The high temperature and high pressure gas generated by the arc will move toward the outlet of the arc extinguishing chamber, which is conducive to the gas blowing and rapid movement of the arc for cooling. In the contactor, allowing the arc to move forward quickly and diffuse in the arc extinguishing chamber helps to lengthen the arc and cool the arc. This is especially true in contactors for DC applications. Since there is no process of voltage and current crossing zero, lengthening the arc and rapidly cooling the arc have become the most important arc extinguishing means in DC contactors.

[0020] On the basis of the existing magnetic blowout arc extinguishing, the present invention arranges a grid arc extinguishing chamber in a limited space. The arc is cut into multiple short arcs by the arc extinguishing chamber grid, thereby improving the initial dielectric strength of the arc gap, and the grid (such as copper grid, ferromagnetic grid, ceramic, etc.) has enhanced cooling and surface recombination effects. For large current interruption (such as rated current), the magnetic driving force generated by the grid arc extinguishing chamber and the magnetic field generated by the permanent magnet (Fleming's law) stretch the arc, and the arc with extended length can be cooled by the gas atmosphere (air, nitrogen or hydrogen, etc.), and at the same time, the pressure gradient of the arc extinguishing system drives the arc to be discharged to the pre-set flow channel cavity (either horizontally or vertically) on both sides. Finally, the arc cooling is further enhanced by using the upper and lower arc extinguishing cavities and metal cups of the contactor. This scheme adopts a method similar to the inner cavity gas outlet to greatly reduce the pressure coefficient of the upper arc extinguishing chamber, reduce the risk of product explosion, and enable the high-temperature arc to flow and circulate effectively for cooling. This not only provides a larger arc extinguishing space, a shorter arc burning time, and a higher arc voltage, but also the flow of the arc gathers metal particles and carbonized impurities in the lower cavity of the contactor, ensuring the cleanliness and insulation resistance of the upper main cavity. In addition, according to the present invention, even if the arc is generated in any direction, it can be induced in the desired direction by current and magnetic force and contact the grid arc extinguishing chamber, thereby extinguishing the arc. In addition, the arc extinguishing cavity shell can also prevent the magnetic properties of the permanent magnet from deteriorating, and can maintain the function of quickly and reliably extinguishing the arc for a long time.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The technical solution of the present invention arranges arc extinguishing grids in a limited cavity space, improves the arc extinguishing capability, and has no polarity requirements for the power supply. It also realizes the airway circulation and diffusion of the high-temperature arc in the upper and lower inner cavities of the contactor, strengthens the arc cooling effect, avoids contamination of the main cavity, and further improves the arc extinguishing capability. The high-temperature gas generated between the moving and static contacts on both sides of the contact bridge flows in their respective air flow channels. In the event of a short circuit fault, the risk of contact welding is reduced and the contact reliability is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 , Figure 2 It is a typical structure of existing high-voltage DC contactors;

[0024] Figure 3a It is a schematic diagram of the structure of an arc extinguishing chamber in the high-voltage DC contactor of the present invention;

[0025] Figure 3b It is a schematic top view of the high voltage DC contactor structure of the present invention;

[0026] Figure 3c It is a schematic diagram of the arc-extinguishing grid structure of the high-voltage DC contactor of the present invention;

[0027] Figure 4a It is a schematic diagram of the structure of the second arc extinguishing chamber in the high voltage DC contactor of the present invention;

[0028] Figure 4b It is a schematic diagram of the structure of the moving contact mounting bracket in the high-voltage DC contactor of the present invention;

[0029] Figure 4c It is a schematic diagram of the structure of the moving contact mounting bracket in the high-voltage DC contactor of the present invention;

[0030] Figure 5a It is a schematic diagram of a grid guide structure of a high-voltage DC contactor of the present invention;

[0031] Figure 5b It is a second schematic diagram of the grid guide structure of the high-voltage DC contactor of the present invention;

[0032] Figure 6a , 6b Two airflow circulation schemes for the upper arc extinguishing cavity of a high-voltage DC contactor;

[0033] Figure 6c , 6d It is a schematic diagram of the structure of two types of air guide plates in the upper arc extinguishing cavity of the high-voltage DC contactor;

[0034] Figure 6e , 6f It is a partially enlarged schematic diagram of two gas guide structures and double gas storage space structure of the upper arc extinguishing cavity of the high-voltage DC contactor;

[0035] Figure 7a Schematic diagram of the non-polarity scheme of the arc extinguishing system of the high-voltage DC contactor contact (top view);

[0036] Figure 7b It is the magnetic force line distribution of permanent magnet of high voltage DC contactor;

[0037] Figure 7c The magnetic field line distribution of the permanent magnet covered by the U-shaped magnetic yoke of the high-voltage DC contactor;

[0038] Figure 7d It is a non-polarity grid arc extinguishing chamber structure of high voltage DC contactor;

[0039] Figure 7e It is a side view of the structure of the non-polarity grid arc extinguishing chamber of the high-voltage DC contactor;

[0040] Figure 8a ,8b,8c are schematic diagrams of the arc-extinguishing chamber structure of the high-voltage DC contactor with non-polarity grid having two arc-isolating plates. DETAILED DESCRIPTION

[0041] In order to make the present invention more clearly understood, a preferred embodiment is described in detail with reference to the accompanying drawings as follows:

[0042] Embodiment 1:

[0043] like Figure 3aThe figure shows a three-dimensional structure scheme disclosed in the present invention. The contactor 301 includes: static contacts 302 and 303, a moving contact 304, arc extinguishing chambers 310 and 311, an electromagnetic system 312 and a housing 313. The electromagnetic system 312 includes a central axis 305, a static iron core 306, a moving iron core 307, a skeleton coil 308, a metal cup 309 and a yoke 314. The contact system includes moving and static contacts (302, 303, 304) for connecting and disconnecting an external DC load circuit; the electromagnetic system 312 drives the moving contact 304 through the moving iron core 307 and the central axis 305 to complete the contact switching action, and the two ends of the moving contact 304 are respectively in contact with the static contacts (302, 303) to form two pairs of moving and static contact contacts, which is called a bridge contact system; the arc extinguishing chambers 310 and 311 are used to complete the arc extinguishing action; the housing 313 is used to accommodate the contact system, the electromagnetic system 312 and the arc extinguishing chambers (310, 311), and also includes lower arc extinguishing cavities 315, 316. The high-temperature arc (319, 320) generated by the moving and static contacts during the disconnection process enters the arc extinguishing chambers 310 and 311 through the upper cavity of the shell, and the arc is cut into multiple short arcs by the grid, thereby improving the initial dielectric strength of the arc gap. At the same time, the grid (such as copper grid, ferromagnetic grid, ceramic, etc.) has the function of strengthening cooling and surface recombination. In addition, the magnetic driving force generated by the arc extinguishing chamber (310, 311) and the magnetic field (Fleming's law) generated by the permanent magnet stretch the arc (319, 320), and the arc (319, 320) with an extended length can be cooled by the gas atmosphere (air, nitrogen or hydrogen, etc.) in which it is located. At the same time, the pressure gradient of the arc extinguishing system drives the arc (319, 320) to be discharged to both sides to the flow channel cavity (either horizontally or vertically) pre-set in the shell 313. That is, before the arc enters the arc extinguishing chamber, the high-temperature gas generated blows the arc into the arc extinguishing chamber, and then is discharged from the arc extinguishing chamber at the rear end of the arc extinguishing chamber together with the high-temperature gas generated by the arc in the arc extinguishing chamber, and enters the lower arc extinguishing cavity between the shell and the outer periphery of the metal cup of the electromagnetic system, thus forming an air flow movement route from the upper arc extinguishing cavity -> arc extinguishing chamber outlet -> lower arc extinguishing cavity. Finally, the upper and lower arc extinguishing cavities (315, 316) of the contactor 301 and the metal cup 309 (with high thermal conductivity) are used to further enhance the cooling of the arc. The arc extinguishing chambers 310 and 311 are arranged at an angle, that is, the stacking direction of the arc extinguishing grid 317 (such as Figure 3c) is at a certain angle with the side wall 313a of the housing 313, so that the exhaust port formed by the arc extinguishing grid 317 discharges the arc in a downwardly inclined manner, rather than facing the side wall 313a directly, which plays a role in guiding the high-temperature gas downward. The arc extinguishing grids are arranged in an alternating manner to keep consistent with the gap between the moving and static contacts. Such an arrangement is conducive to the arc (319, 320) being quickly and effectively discharged to the lower cavities 315 and 316 of the contactor 301 along the guide with the help of the pressure gradient. At the same time, the flow of the arc (319, 320) gathers metal particles and carbonized impurities in the lower cavities 315 and 316, ensuring the cleanliness and insulation resistance of the arc extinguishing chamber (310, 311). In addition, the metal cup 309 not only provides magnetic conductivity for the electromagnetic system 312, but also has a large area of ​​external metal surface and a high thermal conductivity, which is more conducive to the rapid cooling of the arc (319, 320). Figure 3b It is a top view of the lower cavity structure disclosed in the present technical solution. The high-temperature arc (319, 320) circulates inside the shell 313, enters the lower cavities 315 and 316 on both sides, and then diffuses to both sides. At the same time, it is cooled by the gas atmosphere (hydrogen, nitrogen, air, etc.) and the outer surface of the metal cup 309 (higher thermal conductivity).

[0044] exist Figure 3b In the top view, it can be seen that the side wall 313a has an arc-shaped shape protruding outward. When the arcs 319 and 320 are ejected from the arc extinguishing chamber, the arc shape helps the arcs to spread to both sides, which is more conducive to the cooling of the high-temperature gas. Figure 3c The arc extinguishing chamber 310 structure used in this scheme is an inclined structure, wherein the arc extinguishing grid 317 can be made of cold-rolled steel plate, copper plate, Nomex profile or ceramic, etc., and the length of the grid is adjusted according to the moving contact movement path to keep the gap consistent, and arc isolation plates 318 are provided on both sides of the grid to support and fix. The length of the arc extinguishing grid 317 gradually increases along the stacking direction. The stacking direction here is a reference direction, which is only used to illustrate the change of the external dimensions of the arc extinguishing grid 317, and is not a limitation on the protection scope of the patent technology.

[0045] Embodiment 2:

[0046] Figure 4aIt is another three-dimensional structure scheme disclosed by the present invention. The contactor 401 includes: static contacts 302 and 303, a moving contact 304, arc extinguishing chambers 402 and 403, an electromagnetic system 312 and a housing 404. The electromagnetic system 312 includes a central axis 305, a static iron core 306, a moving iron core 307, a skeleton coil 308, a metal cup 309 and a yoke 314. The contact system includes static and dynamic contacts (302, 303, 304) for connecting and disconnecting an external DC load circuit; the electromagnetic system 312 drives the moving contact 304 through the moving iron core 307 and the central axis 305 to complete the contact switching action; the arc extinguishing chambers 402 and 403 are used to complete the arc extinguishing action; the housing 404 is used to accommodate the contact system, the electromagnetic system 312 and the arc extinguishing chambers 402 and 403, and also includes lower arc extinguishing cavities 405 and 406.

[0047] The high-temperature arcs 413 and 414 generated by the moving and static contacts during the breaking process enter the arc extinguishing chambers 402 and 403 through the upper cavity of the shell, and the arcs 413 and 414 are cut into multiple short arcs by the grid, thereby improving the initial dielectric strength of the arc gap. At the same time, the grid (such as copper grid, ferromagnetic grid, ceramic, etc.) has the effect of strengthening cooling and surface recombination. In addition, the magnetic driving force generated by the arc extinguishing chambers 402 and 403 and the magnetic field generated by the permanent magnet (Fleming's law) stretch the arc, and the arcs 413 and 414 with extended length can be cooled by the gas atmosphere (air, nitrogen or hydrogen, etc.) around the location, and at the same time, the pressure gradient of the arc extinguishing system drives the arc to both sides to discharge to the flow channel cavity (either horizontally or vertically) pre-set in the shell 404. Finally, the arc extinguishing cavities 405 and 406 at the upper and lower parts of the contactor 401 and the metal cup 309 are used to further strengthen the cooling of the arcs 413 and 414. Here, the grids in the arc extinguishing chambers 402 and 403 are arranged horizontally, and the arc extinguishing grids are arranged in parallel. This arrangement is conducive to the arcs 413 and 414 to generate a large pressure in the arc extinguishing chamber, and the pressure gradient is effectively discharged to the lower cavities 405 and 406 of the contactor 401. In addition, because the outlet area of ​​the arc extinguishing chamber cavity is relatively large, the arc extinguishing chamber cavity is relatively large. Figure 3aThe solution is small, the initial flow rate of the arcs 413 and 414 is fast, and it is easier to reach the depth of the lower cavities 405 and 406. At the same time, the flow of the arcs 413 and 414 gathers metal particles and carbonized impurities in the lower cavities 405 and 406, ensuring the cleanliness and insulation resistance of the arc extinguishing chambers 402 and 403. The metal cup 309 not only provides magnetic conductivity for the electromagnetic system 312, but also has a large outer metal surface area that is more conducive to the rapid cooling of the arcs 413 and 414. Among them, the distance between the grid plate installed in the arc extinguishing chamber and the shell 404 is greater than the distance between the metal cup 309 near the arc extinguishing chamber outlet and the shell 404. The metal cup 309 is in the lower cavity 405 and 406, and the distance between the metal cup 309 and the shell 404 is greater than the distance between the metal cup 309 near the outlet and the shell 404. In this way, an outlet with a cross-section that decreases from large to small and then becomes larger is formed from the arc extinguishing chambers 402 and 403 to the lower cavities 405 and 406, forming a jet port with a Venturi effect, which accelerates the movement of airflow.

[0048] Figure 4b , 4c : is a schematic diagram of the internal structure of the contact arc extinguishing system (side view), wherein the upper part of the moving contact 304 is equipped with a U-shaped structural member bracket 410, and the bracket 410 is a magnetic conductive material. The upper part of the electromagnetic system 312 is equipped with a partition 411, and the partition 411 is made of a high flame retardant grade plastic material. If necessary, a gas-generating material can be added to enhance the gas blowing effect. By using a plastic material containing hydrogen, the thermal conductivity inside the arc is improved, so that the heat energy of the arc can be easily diffused. The outside of the electromagnetic system 312 is completely covered by a metal cup 309, and the metal cup 309 mainly plays the role of a magnetic yoke, and its large area of ​​metal outer surface assists in arc cooling. The metal cup 309 is made of a magnetic conductive metal material, such as electrical pure iron, and the outer surface is electroplated. The material of the arc extinguishing grid 412 can be cold-rolled steel plate, copper plate, Nomex profile or ceramic, etc. The arc extinguishing grid 412 adopts a U-shaped structure, and the non-polarity of the arc extinguishing chamber 402 can be achieved under the magnetic blowing effect of the permanent magnet.

[0049] Since the upper part of the moving contact 304 is equipped with a U-shaped structural member bracket 410, and the bracket 410 is made of magnetic conductive material. When a short circuit occurs in the power battery system, the short circuit current can reach several thousand amperes, so the moving and static contacts need to withstand a huge electric repulsion force, which is equal to the combined force of the Holm force and the Lorentz force on the contact surface. In the prior art, in order to counteract the electric repulsion force and prevent the contacts from being repelled and welded, a contact spring with a larger force value is required. After adding the U-shaped bracket 410 to the moving contact 304 of the traditional structure, the magnetic line density on the upper part of the contact 304 is significantly increased. Due to the difference in magnetic field strength on the upper and lower sides of the contact 304, a part of the influence of the electric repulsion force can be offset (electrodynamic compensation). Under the premise that the contact spring maintains a certain force value, it can reduce the risk of contact welding and improve contact reliability in the event of a short circuit.

[0050] Embodiment three:

[0051] Figure 5a , 5b The two arc extinguishing chamber structures of the upper arc extinguishing chamber of the contactor (top view); the fan-shaped arc extinguishing chamber cavity 501 accommodates the moving contact 304 and the moving contact arc-starting plate 504 and the arc extinguishing chambers 505 and 507, and the permanent magnets 502 and 503 are arranged in parallel outside the cavity 501. The cavity 501 is a structure with a small middle section and gradually increasing cross-sections at both ends, forming a fan-shaped structure, forming a "bow tie" or "ear" shape, such as Figure 5a The contact system is arranged in the middle part of the cavity 501 where the cross section is smaller, and the arc extinguishing chamber 505 or the arc extinguishing chamber 507 is arranged at the two ends of the cavity 501, that is, the fan-shaped part. The arc extinguishing chamber grid includes a root 505a, 507a close to the contact system and an extension 505b, 507b extending toward the fan-shaped part of the cavity 501. Figure 5a The grid of the arc extinguishing chamber 505 has a T-shaped arc-starting groove 505c in the middle. After the arc gas is generated from the contact system, it moves to the depth of the arc extinguishing chamber 505 through the arc-starting groove 505c. Due to the existence of the T-shaped groove, the side wall of the arc shell, and the effect that the high-temperature gas usually expands from the high-temperature area to the low-temperature area, the arc moves around the grid part on the edge of the T-shaped groove from both sides, so that the arc circulates. Figure 5a . Combined Figure 3a Or the structure of 4a, in terms of spatial position, the arc circulates and moves toward the lower cavities 315 and 316 or the lower cavities 405 and 406, which accelerates the cooling of the gas.

[0052] Further, in the embodiment Figure 5b The grid of the arc extinguishing chamber 507 has a long slot-shaped arc-striking groove 507c with one end open and a separator 507d located at the end of the fan-shaped part of the grid.

[0053] The high-temperature arc (509a, 509b) generated by the moving and static contacts during the high-level breaking process enters the arc extinguishing chamber 505, and the arc (509a, 509b) is cut into multiple short arcs by the grid, thereby improving the initial dielectric strength of the arc gap. At the same time, the grid (such as copper grid, ferromagnetic grid, ceramic, etc.) has the function of strengthening cooling and surface recombination. In addition, the magnetic driving force generated by the arc extinguishing chamber (505) and the magnetic field (Fleming's law) generated by the permanent magnet stretch the arc (509a, 509b), and the arc (509a, 509b) with extended length can be cooled by the gas atmosphere (air, nitrogen or hydrogen, etc.), and at the same time, the pressure gradient of the arc extinguishing system drives the arc (509a, 509b) to flow and circulate in the gas storage space 508 of the fan-shaped cavity. Here, the arc extinguishing chamber 505 is arranged horizontally, the arc extinguishing grids are arranged in parallel, and the grids are made of magnetic materials, such as cold-rolled steel plates. Due to the influence of the magnetic arc-extinguishing grid, the coverage length of the permanent magnets 502 and 503 is greatly reduced compared with the conventional solution, so the arc-extinguishing chamber cavity structure can be improved from the existing rectangular cavity solution to a fan-shaped cavity 501, which not only increases the capacity of the arc-extinguishing chamber, but also promotes the internal circulation of the high-temperature arc (509a, 509b) in the upper layer of the contactor. Figure 5a , 5b As shown, the arc extinguishing chamber 505 adopts two different grid shape structures, and can achieve arc extinguishing effects at the same time.

[0054] Embodiment 4:

[0055] Figure 6a , 6b Two airflow circulation schemes for the upper arc extinguishing cavity of the contactor; Figure 6c 6d is a schematic diagram of the airway structure used in the upper arc extinguishing cavity of the contactor. As shown in the figure, these two schemes use arc extinguishing chambers 601 and 602, and add two arc extinguishing chambers 601 and 602 in the fan-shaped arc extinguishing cavity 501. Figure 6a The air flow guide 603 and Figure 6b The airflow guide 604 is respectively completed Figure 6a , 6b The inner cavity circulation mode of the arc 605 is shown.

[0056] The airflow guide 603 includes a bottom plate 603a, an arc isolation plate 1 603b, and a separator 603c. The bottom plate 603a serves as a support for the arc isolation plate 1 603b and the separator 603c, or the bottom plate 603a, the arc isolation plate 1 603b, and the separator 603c are integrally formed by injection molding. The arc isolation plate 1 603b has an arc isolation wall 603b1 and an air guide plate 603b2. The arc isolation plate 1 603b has two pieces, which are symmetrically arranged on both sides of the separator 603c. The air guide plate 603b2 extends from the arc isolation wall 603b1 and deflects toward the separator 603c.

[0057] The airflow guide 604 includes a bottom plate 604a, an arc isolation plate 604b, a separator 604c, and an arc blocking air guide plate 604d. The bottom plate 604a, the arc isolation plate 604b, and the separator 604c are similar in structure to the airflow guide 603, except that the separator 604c also has an arc blocking air guide plate 604d extending to both sides, and the arc blocking air guide plate 604d includes an arc blocking portion 604d1, an air guide portion 604d2, and a sharpened end portion 604d3. The air guide portion 604d2 extends from the arc blocking portion 604d1 and bends to wrap around the air guide plate 604b2. The sharpened end portion 604d3 is formed at the end of the air guide portion 604d2. The bending portion between the air guide portion 604d2 and the arc blocking portion 604d1 is opposite to the air guide plate 604b2.

[0058] according to Figure 6a , 6c and 6e, an air outlet with a distance a1 formed between the air guide plate 603b2 and the shell wall of the cavity 501; an air outlet with a distance a2 formed between the arc isolation wall 603b1 and the shell wall of the cavity 501; and an air storage space S1 is provided between the air outlet a1 and the air outlet a2.

[0059] according to Figure 6b , 6d and 6f, an air outlet with a distance of b1 is formed between the air guide plate 604b2 and the arc blocking portion 604d1; an air outlet with a distance of b2 is formed between the arc isolation wall 604b1 and the air guide portion 604d2; an air outlet with a distance of b3 is formed between the end 604d3 and the shell wall of the cavity 501; there is an air storage space S2 between the air outlet b1 and the air outlet b2, and the high-temperature gas can enter the air storage space S3 after passing through the air outlet b3. The airflow guide 604 forms a double-layer air guide structure and a double air storage space structure.

[0060] The cross-sectional distance of any of the above-mentioned gas storage spaces is greater than the cross-sectional distance of the gas outlet connected thereto. Thus, according to the Venturi effect, the speed of the high-temperature gas is accelerated. At the same time, the gas storage space is used to accommodate a large amount of gas, and the high-temperature gas will not accumulate near the gas outlet.

[0061] After entering the arc extinguishing chambers 601 and 602, the high-temperature arc is separated into two directions by the guide grooves (the comb-like features of the guide structure 604 separate the outlets of the arc extinguishing chambers 601 and 602 into two parts), and flows along the paths provided by the guide structures 603 and 604, and finally intersects with the disconnection positions of the moving and static contacts at the four outlet positions, completing the flow circulation of the entire inner cavity.

[0062] Embodiment five:

[0063] Figure 7aThe schematic diagram of the non-polarity scheme of the contact arc extinguishing system (top view); wherein the contact arc extinguishing system 710 includes permanent magnets 701 and 702, which are placed in parallel and have opposite polarities (NN or SS). The outer sides of the permanent magnets 701 and 702 are covered by a yoke, which can be made of two U-shaped ferromagnetic parts, such as Figure 7a yokes 703 and 704. That is, in the space between the yokes 703 and 704. In this way, the magnetic field direction of the permanent magnets 701 and 702 starts from the N pole, passes through the respective nearest yokes 703 and 704, and returns to the S pole of the yoke, which standardizes the magnetic field route and makes the magnetic blowing effect better.

[0064] The direction of the magnetic field (711, 712) of the permanent magnet changes from the direction of the magnetic field diverging into the air to the direction of the magnetic field flowing along the U-shaped magnetic yoke, which makes it easier to concentrate the magnetic lines of force at the required position, greatly enhancing the arc extinguishing effect, thereby reducing the volume required for the permanent magnet and saving costs. The contact arc extinguishing system 710 contains two sets of U-shaped arc extinguishing chambers 705 and 706. The direction of the magnetic lines of force of the contact arc extinguishing system 710 is as follows: Figure 7a As shown, the fan-shaped magnetic lines of force (711, 712) formed by the arc extinguishing system arranged in this way can pass through the center of the contact, thereby forming a magnetic blowing force F at the corresponding contact in a direction having an angle with the line connecting the two contacts.

[0065] according to Figure 7a For the moving and static contact system on the left, assuming that the arc current flows from the moving contact to the static contact, and the N poles of the permanent magnets 701 and 702 are opposite, according to Fleming's left-hand rule, the arc current is subjected to the Ampere force F at the lower left, and moves toward the lower left side of the arc extinguishing chamber and gradually moves toward the depth direction of the arc extinguishing chamber; if the arc current flows from the static contact to the moving contact, the arc current is subjected to the Ampere force F at the upper left, and moves toward the upper left side of the arc extinguishing chamber and gradually moves toward the depth direction of the arc extinguishing chamber.

[0066] Permanent magnets 701 and 702 are used to guide the arc at the contact breaking position to the U-shaped arc extinguishing chamber. The direction of the force is shown in the figure, and no matter what the current direction is, the F force tends to be inclined at 45 degrees, which can make the arc extinguishing chambers 705 and 706 play the role of cutting the arc. In this structure of the present invention, the direction of arc blowing is on the diagonal line, which makes the arc blowing space larger, is more conducive to arc breaking, has a stronger arc extinguishing ability, and has a higher space utilization rate of the product.

[0067] Figure 7b The magnetic force lines of the permanent magnet are distributed. Without the covering of the U-shaped magnetic yoke, the magnetic force lines at the disconnection position are more divergent and the arc blowing F force value is smaller. Figure 7c The magnetic force lines distribution of the permanent magnet covered by the U-shaped magnetic yoke. The magnetic force lines at the disconnection position are more concentrated, and the arc blowing F force value is larger.

[0068] Figure 7dIt is a non-polar grid arc extinguishing chamber structure; the U-shaped arc extinguishing chamber 705 is composed of two U-shaped grids 707 and 708, and the two grids are nested with the moving and static contacts respectively to maintain a consistent gap. In the area where the current is large (such as the rated current), the magnetic flux passing through the U-shaped cuts of multiple grids 707 and 708 magnetically drives the arc deep into the space formed by the multiple U-shaped cuts. The long arc is cut into a short arc by the arc extinguishing chamber 705, generating a voltage drop, which is used to maintain the arc voltage rise. If the arc voltage becomes a voltage higher than the power supply voltage, the arc is extinguished. In addition, during each arc cutting process, the heat transfer efficiency of the large-area grid is higher, which helps the arc to cool quickly.

[0069] Figure 7e This is a side view of this solution; according to the present invention, even if the arc is generated in any direction, it can be induced in the desired direction by current and magnetic force and contact the arc shielding component, thereby making the arc extinguished, greatly slowing down the degradation rate of the housing 404. The permanent magnets 701 and 702 are assembled inside the housing 404 and physically isolated from the inside of the arc extinguishing chamber to prevent arc contamination. Therefore, the arc extinguishing chamber housing 404 can also prevent the magnetic properties of the permanent magnets 701 and 702 from deteriorating, and can maintain the function of quickly and reliably extinguishing the arc for a long time.

[0070] according to Figure 8a , 8b 8c, this embodiment also has an arc isolation plate 3041, which is installed on the central axis 305 and located in the middle of the moving contact 304, separating the two contact points of the moving contact 304 into two spaces, so that the high-temperature gas generated between the moving and static contacts on both sides of the contact bridge flows in their respective air flow channels.

[0071] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and equivalent changes made by using the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A DC contactor arc extinguishing system, the DC contactor comprising a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a housing; the electromagnetic system comprises a central axis, a static iron core, a moving iron core, a skeleton coil, a metal cup and a yoke iron; Features: The arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and an airflow guide; an arc extinguishing cavity extending from the upper cavity of the DC contactor to the lower cavity is provided between the shell and the outer periphery of the metal cup of the electromagnetic system; a partition is provided below the moving contact in the upper cavity of the DC contactor, and an arc extinguishing chamber is provided on the partition, and the arc extinguishing chamber is provided at the outer periphery of the relative motion area of ​​the moving contact and the static contact; an opening is provided on one side of the arc extinguishing chamber relative to the relative motion area of ​​the moving contact and the static contact, and an opening is also provided on the other side of the arc extinguishing chamber relative to the relative motion area of ​​the moving contact and the static contact; The partition is also provided with an airflow guide (603); The airflow guide (603) comprises a bottom plate (603a), an arc isolation plate (603b), and a partition (603c); the bottom plate (603a) is provided on the partition, and the bottom plate (603a) is provided with an arc isolation plate (603b) and a partition (603c); the partition (603c) is provided at an opening of the arc extinguishing chamber on the other side of the relative motion region of the moving contact and the stationary contact; two arc isolation plates (603b) are symmetrically provided on both sides of the arc extinguishing chamber adjacent to the relative motion region of the moving contact and the stationary contact and with the partition (603c) as the center, and comprise arc isolation walls (603b1) and air guide plates (603b2); the arc isolation walls (603b1) provided on both sides of the arc extinguishing chamber extend toward the partition (603c) and are provided with air guide plates (603b2).

2. A DC contactor arc extinguishing system, the DC contactor comprising a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a housing; the electromagnetic system comprises a central axis, a static iron core, a moving iron core, a skeleton coil, a metal cup and a yoke iron; Features: The arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and an airflow guide; an arc extinguishing cavity extending from the upper cavity of the DC contactor to the lower cavity is provided between the shell and the outer periphery of the metal cup of the electromagnetic system; a partition is provided below the moving contact in the upper cavity of the DC contactor, and an arc extinguishing chamber is provided on the partition, and the arc extinguishing chamber is provided at the outer periphery of the relative motion area of ​​the moving contact and the static contact of the device; an opening is provided on one side of the arc extinguishing chamber relative to the relative motion area of ​​the moving contact and the static contact, and an opening is also provided on the other side of the arc extinguishing chamber relative to the relative motion area of ​​the moving contact and the static contact; The partition is also provided with an airflow guide (604); The airflow guide (604) comprises a bottom plate (604a), an arc isolation plate (604b), a separator (604c) and an arc blocking air guide plate (604d); the separator is provided with the bottom plate (604a), and the bottom plate (604a) is provided with an arc isolation plate (604b), a separator (604c) and an arc blocking air guide plate (604d); the separator (604c) is provided at an opening on the other side of the arc extinguishing chamber relative to the relative motion region of the moving contact and the stationary contact; two arc isolation plates (604b) symmetrically provided with the separator (604c) on both sides of the arc extinguishing chamber adjacent to the relative motion region of the moving contact and the stationary contact comprise arc isolation walls (604b1) and air guide plates (604b2), and the arc isolation walls (604b1) provided on both sides of the arc extinguishing chamber are provided with an arc isolation plate (604b2). 604b1) extends to the partition (604c) and is provided with an air guide plate (604b2); the partition (604c) is provided with an arc-blocking air guide plate (604d) extending to both sides, the arc-blocking air guide plate (604d) comprising an arc-blocking portion (604d1), an air guide portion (604d2) and a sharpened end portion (604d3); the partition (604c) is provided with an arc-blocking portion (604d1) extending to both sides, the arc-blocking portion (604d1) is bent and extended to be provided with an air guide portion (604d2) surrounding the air guide plate (604b2), and a sharpened end portion (604d3) is provided at the end of the air guide portion (604d2); the bent connection between the air guide portion (604d2) and the arc-blocking portion (604d1) corresponds to the air guide plate (604b2).

3. A DC contactor arc extinguishing system as claimed in claim 1 or 2, Features: The arc extinguishing chamber includes an arc extinguishing grid and an arc isolating plate 2. The arc extinguishing chamber is provided with two arc isolating plates 2 on both sides of the relative movement area of ​​the moving contact and the static contact. The arc isolating plates 2 are arranged on the partition, and the plate surface of the arc isolating plates 2 is parallel to the central axis of the moving contact of the DC contactor; a sheet-shaped arc extinguishing grid is arranged between the two arc isolating plates 2, perpendicular to the arc isolating plates 2 and parallel to each other.

4. A DC contactor arc extinguishing system as claimed in claim 3, Features: The cross section of the shell perpendicular to the central axis is set to a bowtie-shaped structure with a small middle cross section and gradually larger cross sections on both sides. The moving contact and the static contact are arranged in the middle part of the cavity with a smaller cross section, and the arc extinguishing chamber is arranged in the fan-shaped parts on both sides of the cavity.

5. A DC contactor arc extinguishing system as claimed in claim 3, Features: The arc extinguishing grid is provided with an arc striking groove.

6. A DC contactor arc extinguishing system as claimed in claim 1, Features: An air outlet one (a1) is provided between the air guide plate (603b2) of the air flow guide (603) and the shell wall of the shell; an air outlet two (a2) is provided between the arc isolation wall (603b1) and the shell wall of the shell; and an air storage space one (S1) is provided between the air outlet one (a1) and the air outlet two (a2).

7. A DC contactor arc extinguishing system as claimed in claim 2, Features: An air outlet three (b1) is provided between the air guide plate (604b2) of the airflow guide (604) and the arc blocking portion (604d1); an air outlet four (b2) is provided between the arc isolation wall (604b1) and the air guide portion (604d2); an air outlet five (b3) is provided between the sharpened end (604d3) and the shell wall of the shell; an air storage space two (S2) is provided between the air outlet three (b1) and the air outlet four (b2), and an air storage space three (S3) is provided between the air outlet five (b3) and the shell wall of the shell.

8. A DC contactor arc extinguishing system as claimed in claim 3, Features: The arc-extinguishing grid is made of cold-rolled steel plate, copper plate, meta-aromatic polyphthalamide fiber Nomex profile or ceramic.

9. A DC contactor arc extinguishing system as claimed in claim 1 or 2, Features: The moving contact is provided with a U-shaped structural member bracket, and the bracket is made of magnetic conductive material.

10. A DC contactor arc extinguishing system as claimed in claim 1 or 2, Features: The top of the moving contact is provided with an arc isolation plate three, which is arranged at the middle position of the top of the moving contact to separate the two contact points of the moving contact and the static contact into two spaces.

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