Vacuum arc-extinguishing chamber

Abstract

The invention provides a vacuum arc-extinguishing chamber which comprises an insulating shell, two conducting rods, a moving contact assembly and a static contact assembly, the two conducting rods, the moving contact assembly and the static contact assembly are arranged in the insulating shell, the two conducting rods are coaxial and oppositely arranged, and the moving contact assembly and the static contact assembly are assembled on the two conducting rods respectively; each of the moving contact assembly and the static contact assembly comprises a horseshoe-shaped iron core and a contact, and the horseshoe-shaped iron core is provided with an unclosed opening side; the contact is provided with an eddy current notch, and the eddy current notch is located in the range of the opening side of the horseshoe-shaped iron core. The generation of weak eddy current can be reduced, and the effect of reducing temperature rise is achieved; and a horseshoe-shaped iron core can be matched to reinforce the generation of a longitudinal magnetic field, so that the effect of preventing the surface of the contact from being excessively ablated due to aggregation-type electric arcs formed by electric arc aggregation is further enhanced.

Description

Technical Field

[0001] The invention relates to the field of high-voltage electrical switches, and in particular to a vacuum interrupter. Background Art

[0002] The vacuum interrupter, also known as the vacuum switch tube, is the core component of medium and high voltage power switches. Its main function is to quickly extinguish the arc after the medium and high voltage circuit is cut off from the power supply through the excellent insulation of the vacuum inside the tube, thus avoiding accidents and unexpected events. It is mainly used in power transmission and distribution control systems.

[0003] With the development of technology, the performance requirements of switchgear are getting higher and higher, which leads to higher requirements for vacuum arc extinguishing chambers. Adding a horseshoe-shaped iron core to the contact group can generate a longitudinal magnetic field, which can effectively prevent the arc from gathering to form a concentrated arc and causing excessive ablation of the contact surface. At the same time, according to the skin effect (the current is more concentrated in the area close to the outer surface of the conductor, and the closer to the center of the conductor, the smaller the current density), it is known that the current density at the periphery of the contact is very large; eddy currents will be generated, resulting in a large temperature rise; in this regard, the prior art sets holes on the contacts to cut off the eddy currents, although the method is effective; however, the holes of this structure are point-symmetrically distributed on the contacts. Such a setting easily leads to the superposition of electric fields, resulting in a greater electric field concentration effect, which is easy to cause dangers such as electric shock, electric sparks, and electrical insulation damage. Summary of the invention

[0004] Therefore, the present invention provides a vacuum interrupter to solve the above problems.

[0005] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0006] A vacuum interrupter comprises an insulating shell and two conductive rods, a moving contact assembly and a stationary contact assembly arranged in the insulating shell, wherein the two conductive rods are coaxial and oppositely arranged, and the moving contact assembly and the stationary contact assembly are respectively assembled on the two conductive rods; the moving contact assembly and the stationary contact assembly both comprise a horseshoe-shaped iron core and a contact, wherein the horseshoe-shaped iron core has an unclosed open side; wherein an eddy current notch is arranged on the contact, and the eddy current notch is within the range of the open side of the horseshoe-shaped iron core.

[0007] Furthermore, on a projection plane perpendicular to the axial direction of the conductive rod, the opening side of the horseshoe-shaped core of the moving contact assembly and the opening side of the horseshoe-shaped core of the stationary contact assembly are oriented in opposite directions, forming an electric field complementary structure.

[0008] Furthermore, the structural relationship between the moving contact assembly and the stationary contact assembly is a structure obtained by mutual central reflection transformation; that is, the moving contact assembly is equivalent to the structure obtained by rotating the stationary contact assembly 180° around the central axis of the conductive rod after mirror symmetry.

[0009] Furthermore, the number of eddy current cutouts on the same contact is one.

[0010] Furthermore, the eddy current cutout is a cutout extending from the outer peripheral wall of the contact toward the central area, and the diameter of the cutout on the outside of the eddy current cutout is larger than the diameter of the cutout on the inside.

[0011] Furthermore, the contact is a circular contact, and the eddy current cutout is a fan-shaped cutout.

[0012] Furthermore, the two sector-shaped edges of the eddy current cutout are transitioned through an arc segment.

[0013] Furthermore, the angle of the eddy current cutout does not exceed 50°.

[0014] Furthermore, a contact through hole penetrating to the contact surface is provided in the central area of ​​the contact.

[0015] Furthermore, the side of the contact through hole facing the contact surface is a trumpet-shaped hole section with a gradually increasing hole diameter.

[0016] Furthermore, the moving contact assembly and the stationary contact assembly each include a fixing plate, which is fixedly connected to the conductive rod; the horseshoe-shaped iron core is formed by stacking a plurality of magnetic pole pieces and is fixed to the fixing plate by rivets.

[0017] Furthermore, a non-circular limiting slot is provided on the fixing plate, and the contact piece has a through hole located in the limiting slot; the cross-sectional shape of the end of the conductive rod is adapted to the limiting slot and a mounting boss is raised on the end face, and the mounting boss is inserted into the through hole of the contact piece, and the end of the conductive rod is assembled in the limiting slot to form a circumferential limiting fit.

[0018] The technical solution provided by the present invention has the following beneficial effects:

[0019] 1. This scheme is based on the setting of horseshoe-shaped iron core, combined with the setting of eddy current cuts on the contacts, and the eddy current cuts are within the range of the opening side of the horseshoe-shaped iron core; the contacts have weak electric field areas at the eddy current cuts, while the remaining intact parts have electric field strengthening areas; at the same time, the eddy current cuts are within the range of the opening side of the horseshoe-shaped iron core, so the contrast between strong and weak areas is more obvious. That is, the setting of eddy current cuts can not only reduce the generation of weak eddy currents and achieve the effect of reducing temperature rise; it can also cooperate with the horseshoe-shaped iron core to strengthen the generation of longitudinal magnetic fields, and further enhance the effect of avoiding arc aggregation to form concentrated arcs and cause excessive ablation of the contact surface.

[0020] 2. On the projection plane perpendicular to the axial direction of the conductive rod, the opening side of the horseshoe-shaped core of the moving contact assembly and the opening side of the horseshoe-shaped core of the static contact assembly are in opposite directions, forming an electric field complementary structure. This arrangement allows the strong and weak electric fields to be matched between the two groups of contact assemblies (moving contact assemblies and static contact assemblies), that is, the reinforced area of ​​one group of contact assemblies directly corresponds to the weak area of ​​the other group of contact assemblies. This one-to-one correspondence achieves the effect of uniform electric field on the whole, and at the same time forms a stable longitudinal magnetic field, achieving the arc extinguishing goal and ensuring a good electric field environment.

[0021] 3. A fixed plate structure is adopted, and the contact and the horseshoe-shaped iron core are fixed on the fixed plate; the horseshoe-shaped iron core can be assembled in an exposed manner, which is helpful for the heat dissipation capacity of the contact assembly during experiments; it is also convenient for assembly and mass production, and it is easy to correct errors and repair to improve the yield rate.

[0022] 4. The number of eddy current cuts on the same contact is only one, and a single cut is easy to process, avoiding the problem of multiple cuts requiring coordination with positioning references, weakening contact strength and causing failure.

[0023] 5. The contact is a circular contact, and the eddy current cut is a fan-shaped cut; a structure is formed in which the outer cut of the contact is large and the gap in the central area is small, which reduces the current density in the outer area while ensuring the contact area of ​​the contact in the middle area, improves the utilization rate of the contact surface, further reduces the contact resistance, and reduces heat.

[0024] 6. A contact through hole penetrating to the contact surface is provided in the central area of ​​the contact. Furthermore, the side of the contact through hole facing the contact surface is a trumpet-shaped hole section with a gradually increasing aperture; the heat accumulation in the central area can be reduced; at the same time, when the contacts are separated, the heat overflows, and the trumpet-shaped hole section increases the heat dissipation area, thereby improving the heat dissipation efficiency of the contacts and reducing the temperature rise of the contacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is a partial structural schematic diagram of a vacuum interrupter in an embodiment;

[0026] Figure 2 The figure shows a schematic diagram of the matching structure of the contact, the fixing plate and the horseshoe-shaped iron core in the embodiment;

[0027] Figure 3 Shown Figure 2 a cross-sectional view of the structure shown;

[0028] Figure 4 Shown is a schematic diagram of the structure of the contact;

[0029] Figure 5 Shown Figure 2 a top view of the structure shown;

[0030] Figure 6 Shown is a schematic diagram of the structure of one of the conductive rods. DETAILED DESCRIPTION

[0031] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0032] In the description of the present invention, terms such as "up", "down", "left", "right", "front", "back", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0033] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0034] Reference Figures 1 to 6 As shown, a vacuum interrupter provided in this embodiment comprises an insulating housing (not shown) and two conductive rods 10, a moving contact assembly 1 and a stationary contact assembly 2 arranged in the insulating housing. The two conductive rods 10 are coaxial and arranged oppositely, and the moving contact assembly 1 and the stationary contact assembly 2 are respectively assembled on the two conductive rods 10; in this embodiment, the moving contact assembly 1 and the stationary contact assembly 2 are arranged correspondingly up and down. The moving contact assembly 1 and the stationary contact assembly 2 both comprise a horseshoe-shaped iron core 20 and a contact 30, and the horseshoe-shaped iron core 20 has an unclosed opening side 22; the contact 30 is a circular contact, the contact 30 is connected to the end of the conductive rod 10, and has a contact surface 301 facing the opposite contact, and the horseshoe-shaped iron core 20 is arranged on the side away from the contact surface 301 of the contact 30; when the switch is closed, the contact surface 301 of the contact 30 of the moving contact assembly 1 contacts the contact surface 301 of the stationary contact assembly 2.

[0035] The contact 30 is provided with an eddy current notch 31, and the eddy current notch 31 is within the range of the opening side 22 of the horseshoe core 20. Due to the setting of the eddy current notch 31, the contact 30 has an electric field weak area at the eddy current notch 31, and the remaining complete part has an electric field enhanced area; at the same time, the eddy current notch 31 is within the range of the opening side 22 of the horseshoe core 20, so the contrast between the strong and weak areas is more obvious. That is, the setting of the eddy current notch 31 can not only effectively reduce the generation of weak eddy currents and achieve the effect of reducing temperature rise; it can also cooperate with the horseshoe core 20 to strengthen the generation of the longitudinal magnetic field, that is, the high voltage is connected from one end, the current flows from the conductive rod 10 into the contact assembly, and the current path flows through the contact 30 along the horseshoe core 20. This process generates a longitudinal magnetic field due to the regular movement of the electric charge. Finally, the current flows to the opposite contact 30 to form a loop. Since the eddy current cutout 31 of the contact 30 is within the range of the opening side 22 of the horseshoe-shaped iron core 20 (that is, the current paths are basically the same), the generated magnetic fields are superimposed on each other to achieve the purpose of enhancing the magnetic field, thereby further enhancing the effect of preventing the arc from gathering to form a concentrated arc and causing excessive ablation on the surface of the contact 30.

[0036] With the above-mentioned vacuum interrupter structure, after the moving contact assembly 1 and the stationary contact assembly 2 are closed, according to the skin effect (the current is more concentrated in the area close to the outer surface of the conductor, and the closer to the center of the conductor, the smaller the current density), the current density at the periphery of the contact 30 is very large, thereby generating eddy currents; the setting of the eddy current cutout 31 on the contact 30 can effectively cut off the eddy current (that is, it can effectively reduce the generation of weak eddy currents). At the same time, in the process of disconnecting and separating the moving contact assembly 1 and the stationary contact assembly 2, the horseshoe-shaped iron core 20 cooperates with the setting of the eddy current cutout 31 of the contact 30 to generate a stronger longitudinal magnetic field, effectively avoiding the arc gathering to form a concentrated arc and causing excessive ablation of the surface of the contact 30.

[0037] Further preferably, on a projection plane perpendicular to the axial direction of the conductive rod 10, the opening side 22 of the horseshoe-shaped core 20 of the moving contact assembly 1 and the opening side 22 of the horseshoe-shaped core 20 of the stationary contact assembly 2 are oriented in opposite directions, such as Figure 1-2 As shown, the eddy current cutout 31 of the contact 30 of the moving contact assembly 1 and the open side 22 of the horseshoe-shaped iron core 20 are both facing right, then the right side of the moving contact assembly 1 is a weak electric field area, and the left side of the moving contact 1 is a strong electric field area; and the eddy current cutout 31 of the contact 30 of the static contact assembly 2 and the open side 22 of the horseshoe-shaped iron core 20 are both facing left, then the right side of the static contact assembly 2 is a strong electric field area, and the left side of the static contact assembly 2 is a weak electric field area. In the open state, the strong electric field on the left side of the moving contact assembly 1 and the weak electric field on the left side of the static contact assembly 2 complement each other, and the weak electric field on the right side of the moving contact assembly 1 and the strong electric field on the right side of the static contact assembly 2 complement each other; such a one-to-one correspondence achieves the effect of uniform electric field on the whole, and at the same time forms a stable longitudinal magnetic field, achieves the arc extinguishing goal, and ensures a good electric field environment.

[0038] More preferably, the structural relationship between the moving contact assembly 1 and the stationary contact assembly 2 is a structure obtained by mutual central reflection transformation; that is, the moving contact assembly 1 is equivalent to the structure obtained by rotating the stationary contact assembly 2 by 180° around the central axis of the conductive rod 10 after mirror symmetry. With such an arrangement, the strengths of the strong and weak electric fields generated by the moving contact assembly 1 and the stationary contact assembly 2 are basically the same and complementary, that is, the strength of the strong electric field generated by the moving contact assembly 1 is basically the same as the strength of the strong electric field generated by the stationary contact assembly 2, and the strength of the weak electric field generated by the moving contact assembly 1 is basically the same as the strength of the weak electric field generated by the stationary contact assembly 2; the electric field complementary effect is more significant after matching.

[0039] Furthermore, in this embodiment, the number of eddy current notches 31 on the same contact 30 is one, that is, the number of eddy current notches 31 on the contact 30 of the moving contact assembly 1 and the number of eddy current notches 31 on the contact 30 of the stationary contact assembly 2 are both one; a single notch is easy to process. Of course, in other embodiments, multiple eddy current notches 31 can also be set on the same contact 30, and the number of eddy current notches 31 on the contact 30 of the moving contact assembly 1 and the number of eddy current notches 31 on the contact 30 of the stationary contact assembly 2 can also be different, such as the number of eddy current notches 31 on the same contact 30 is set multiple, as long as the multiple eddy current notches 31 are all within the range of the opening side 22 of the horseshoe core 20. When multiple eddy current notches 31 are used, although the above-mentioned effect of effectively reducing the generation of weak eddy currents and cooperating with the horseshoe core 20 to strengthen the longitudinal magnetic field can also be achieved; however, considering the use of the arc extinguishing chamber using the longitudinal magnetic contact, a larger opening and closing force is required, which also leads to the need for a larger contact pressure. Therefore, providing a plurality of eddy current cutouts 31 on the contact 30 within the range of the opening side 22 of the horseshoe core 20 may directly cause the contact 30 to crack or dent due to the large contact pressure during the experimental operation, and ultimately lead to arc extinguishing failure. Secondly, the more eddy current cutouts 31 are provided on the contact 30, the smaller its contact area, the greater the contact resistance, and the temperature rise increases accordingly; finally, if a plurality of eddy current cutouts 31 are provided on the contact 30, for the traditional contact 30, although it can better balance the magnetic field generated by the contact 30, for the structure with the horseshoe core 20, it is more necessary for the contact 30 to have an uneven distribution of the magnetic field, which is used to superimpose the magnetic field generated by the horseshoe core 20, so as to form a distinct magnetic field opposing area, and realize the strong and weak offset of the opposing electric fields at the moving and static ends. Therefore, it is more preferred that the number of eddy current cutouts 31 on the same contact 30 is one.

[0040] Furthermore, in this embodiment, the contact 30 adopts a circular contact with no tip on the periphery to ensure the contact breaking performance. At the same time, the eddy current notch 31 is a notch extending from the outer peripheral wall of the contact 30 to the central area, and the outer notch diameter of the eddy current notch 31 is larger than the inner notch diameter; more specifically, the eddy current notch 31 is set as a fan-shaped notch, that is, the notch diameter of the eddy current notch 31 gradually decreases linearly from the outside to the inside; forming a structure in which the outer notch of the contact 30 is large and the notch in the central area is small. According to the skin effect, the current density of the outer periphery of the contact 30 is greater than the current density of the central area, and the greater the current density, the stronger the eddy current effect, and the higher the contact temperature rise. Therefore, it is designed to have a large outer notch, so that the current density is reduced to a greater extent, the eddy current effect is weak, and the temperature rise can be further reduced; and the small notch in the central area ensures that the contact area of ​​the contact 30 in the middle area is larger, and the utilization rate of the contact surface is improved. The larger the contact area in the middle area, the smaller the resistance, and the lower the temperature rise. Therefore, by designing the above-mentioned fan-shaped notch, the current density in the peripheral area is reduced while the contact area of ​​the contact in the middle area is ensured, further reducing heat generation. Of course, in other embodiments, the eddy current notch 31 is not limited to a fan-shaped notch, such as the notch diameter of the eddy current notch 31 can also be set to decrease in a step-like manner from the outside to the inside.

[0041] Further preferably, the angle of the eddy current cutout 31 does not exceed 50° to ensure that there is sufficient contact area between the contacts 30 .

[0042] The central area of ​​the contact 30 is provided with a contact through hole 32 which penetrates to its contact surface 301; further, the side of the contact through hole 32 facing the contact surface 301 is a trumpet-shaped hole section 321 with a gradually increasing aperture; the heat accumulation in the central area can be reduced; at the same time, when the contacts are separated, the heat overflows, and the trumpet-shaped hole section 321 increases the heat dissipation area, improves the heat dissipation efficiency of the contacts, and reduces the temperature rise of the contacts.

[0043] The two sector edges of the eddy current cutout 31 are transitioned through an arc segment 311 to avoid tip discharge.

[0044] The moving contact assembly 1 and the stationary contact assembly 2 also include a fixing plate 40, which is fixedly connected to the conductive rod 10. The horseshoe core 20 is formed by stacking a plurality of magnetic pole pieces 21 and fixed to the fixing plate 40 by riveting with rivets 23. Such a configuration enables the horseshoe core 20 to form an exposed assembly, that is, the horseshoe core 20 does not need to be covered by an outer cover, and an exposed assembly is realized, specifically, it is exposed in the closed space of the insulating shell. In this way, the heat dissipation capacity of the contact assembly (i.e., the moving contact assembly 1 and the stationary contact assembly 2) during the experiment is facilitated; at the same time, it is also convenient to assemble, realize mass production, and is easy to correct errors and repair to improve the yield rate. Of course, in other embodiments, the structure of the fixing plate 40 may not be adopted; when the structure of the fixing plate 40 is not adopted, the horseshoe core 20 can be fixed to the conductive rod 10 by other means (such as through an outer cover), and so on.

[0045] The fixing plate 40 is provided with a non-circular limiting slot 41. For example, in this embodiment, the non-circular limiting slot is a structure remaining after a "D"-shaped area is cut off from a complete circle; the contact 30 has a through hole located in the limiting slot 41, and specifically, the through hole is the contact through hole 32; the cross-sectional shape of the end of the conductive rod 10 is adapted to the limiting slot 41 and a mounting boss 12 is raised on the end face 11, that is, the end face 11 of the end of the conductive rod 10 is also cut off a "D"-shaped structure to form a limiting step 13; the mounting boss 12 is inserted into the contact through hole 32 of the contact 30, and the end of the conductive rod 10 is assembled in the limiting slot 41 to form a circumferential limiting fit. With such a configuration, the alignment is better and reverse installation is avoided. Of course, in other embodiments, the structure of the non-circular limiting slot 41 and the end of the conductive rod 10 adapted thereto is not limited thereto, and may also be a semicircle, a right triangle, a diamond or other irregular shaped structures.

[0046] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A vacuum interrupter, comprising an insulating housing, two conductive rods, a moving contact assembly and a stationary contact assembly arranged in the insulating housing, wherein the two conductive rods are coaxial and oppositely arranged, and the moving contact assembly and the stationary contact assembly are respectively assembled on the two conductive rods; the moving contact assembly and the stationary contact assembly both comprise a horseshoe-shaped iron core and a contact, and the horseshoe-shaped iron core has an unclosed opening side; characterized in that: The contact is provided with an eddy current notch, and the eddy current notch is within the range of the opening side of the horseshoe-shaped iron core.

2. The vacuum interrupter according to claim 1, characterized in that: On a projection plane perpendicular to the axial direction of the conductive rod, the opening side of the horseshoe-shaped core of the moving contact assembly and the opening side of the horseshoe-shaped core of the stationary contact assembly are oriented in opposite directions, forming an electric field complementary structure.

3. The vacuum interrupter according to claim 2, characterized in that: The structural relationship between the moving contact assembly and the stationary contact assembly is a structure obtained by mutual central reflection transformation; that is, the moving contact assembly is equivalent to the structure obtained by rotating the stationary contact assembly 180° around the central axis of the conductive rod after mirror symmetry.

4. The vacuum interrupter according to claim 1, 2 or 3, characterized in that: The number of eddy current cuts on the same contact is one.

5. The vacuum interrupter according to claim 4, characterized in that: The eddy current cut is a cut extending from the outer peripheral wall of the contact to the central area, and the cut diameter of the eddy current cut is larger than the cut diameter of the inner cut.

6. The vacuum interrupter according to claim 5, characterized in that: The contact is a circular contact, and the eddy current cutout is a fan-shaped cutout.

7. The vacuum interrupter according to claim 6, characterized in that: The two sector edges of the eddy current cutout are transitioned through a circular arc segment.

8. The vacuum interrupter according to claim 6, characterized in that: The angle of the eddy current cutout does not exceed 50°.

9. The vacuum interrupter according to claim 1, characterized in that: A contact through hole penetrating to the contact surface is arranged in the central area of ​​the contact.

10. The vacuum interrupter according to claim 9, characterized in that: The side of the contact through hole facing the contact surface is a trumpet-shaped hole section with a gradually increasing hole diameter.

11. The vacuum interrupter according to claim 1, characterized in that: The moving contact assembly and the stationary contact assembly also include a fixing plate, which is fixedly connected to the conductive rod. The horseshoe-shaped iron core is formed by stacking a plurality of magnetic pole pieces and is fixed to the fixing plate by rivets.

12. The vacuum interrupter according to claim 11, characterized in that: A non-circular limiting slot is provided on the fixing plate, and the contact piece has a through hole located in the limiting slot; the cross-sectional shape of the end of the conductive rod is adapted to the limiting slot and a mounting boss is raised on the end face, and the mounting boss is inserted into the through hole of the contact piece, and the end of the conductive rod is assembled in the limiting slot to form a circumferential limiting fit.

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