Vacuum arc-extinguishing chamber

Abstract

The invention relates to the technical field of vacuum switches, in particular to a vacuum arc-extinguishing chamber. The vacuum arc-extinguishing chamber comprises a shell, an end shielding cover welded and fixed on the shell and a cover plate welded and fixed on the end shielding cover, the cover plate comprises an annular section extending along the axial direction of the cover plate, and the cover plate comprises a welding ring arranged at the tail end of the annular section. One side face of the welding ring in the axial direction is connected with the annular section, the other side face of the welding ring forms a welding face to be welded with the end shielding cover, the ring width of the welding ring is larger than the wall thickness of the annular section, the ring width direction of the welding ring is consistent with the radial direction of the welding ring, and the welding face with the large welding area can be formed through the welding ring with the large radial width. The area of the welding surface is larger than the area of the cross section of the annular section, so that the welding structure can effectively increase the welding area, improve the welding strength of the cover plate and the end shielding cover of the vacuum arc-extinguishing chamber, and avoid the situation that the welding strength is affected due to the fact that the annular section of the cover plate needs to be set to be very thin.

Description

Technical Field

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

[0002] With the continuous development of the electric power industry and the gradual improvement of environmental protection requirements, vacuum interrupters are developing towards high-voltage power transmission and distribution, requiring higher structural strength for vacuum interrupters. The basic structure of the existing vacuum interrupter can be found in the Chinese invention patent application CN114974991A, which discloses a vacuum interrupter for on-load tap changers. The vacuum interrupter includes a metallized porcelain shell, a main shielding cover, a moving cover, a static cover, a static tube core, a moving tube core, and an end shielding cover. There are two metallized porcelain shells, and the main shielding cover is arranged between the two metallized porcelain shells. The main shielding cover is fixedly connected to the two metallized porcelain shells to form the outer shell of the vacuum interrupter. The moving cover and the static cover are respectively arranged in the axial direction of the outer shell. At both ends, the static tube core passes through the static cover plate, and the dynamic tube core passes through the dynamic cover plate. The opposite ends of the dynamic tube core and the static tube core are respectively provided with a moving contact and a static contact. The dynamic tube core and the static tube core constitute a contact rod. The moving contact and the static contact are located in the inner cavity of the shell. The dynamic cover plate and the static cover plate both constitute the cover plate of the arc extinguishing chamber. The two cover plates are respectively covered on both ends of the shell. End shielding covers are respectively provided at positions close to the corresponding cover plates at both ends of the shell. The end shielding covers are located on one side of the cover plate close to the inner cavity of the shell. The end shielding covers are welded and embedded between the end of the cover plate and the metallized porcelain shell.

[0003] The end shield has an annular flange, which is axially attached to the end face of the metallized porcelain shell and welded. The cover includes a main body and an axially extending annular segment, one end of the annular segment is connected to the main body, the other end is the end, and the end face is axially attached to the annular flange of the end shield and welded. The metallized porcelain shell, the end shield and the cover are fixed by brazing. Brazing material is filled between the axial side of the annular flange of the end shield and the end face of the shell, and the other axial side of the annular flange of the end shield and the end face of the annular segment of the cover. The cover is made of stainless steel, and the end shield is made of copper.

[0004] Since the transmission-grade vacuum interrupter has a large diameter and volume, in order to reduce the sealing stress between the stainless steel cover plate and the end shield, the wall thickness of the annular section of the cover plate is very thin, and the weld sealing stress can be effectively reduced by deforming the annular section with a thinner wall thickness of the cover plate. However, since the thickness of the annular section of the cover plate needs to be set smaller, the area of ​​the welding surface formed by the welding end surface of the annular section of the cover plate is smaller, and there is a hidden danger of welding strength. Summary of the invention

[0005] The object of the present invention is to provide a vacuum interrupter to solve the problem of low welding strength in the existing vacuum interrupter due to the thin wall thickness of the annular section of the cover plate resulting in a small area of ​​the welding surface matching the end shield.

[0006] The technical solution of the vacuum interrupter of the present invention is: A vacuum arc extinguishing chamber comprises an outer shell, an end shielding cover welded and fixed to the outer shell, and a cover plate welded and fixed to the end shielding cover, wherein the cover plate comprises an annular segment extending along its axial direction, and the cover plate comprises a welding ring arranged at the end of the annular segment, wherein one axial side surface of the welding ring is connected to the annular segment, and the other side surface constitutes a welding surface for welding to the end shielding cover, and the ring width of the welding ring is greater than the wall thickness of the annular segment.

[0007] Beneficial effect: The present invention is an improvement on the vacuum arc chamber in the prior art. A welding ring is arranged at the end of the axially extending annular segment of the cover plate. One axial side surface of the welding ring is connected to the end of the annular segment, and the other side surface forms a welding surface of the cover plate for welding with the end shielding cover. The ring width of the welding ring is greater than the wall thickness of the annular segment. The ring width direction of the welding ring is consistent with its radial direction. A welding surface with a larger radial width can be formed by using a welding ring with a larger radial width. The area of ​​the welding surface is greater than the cross-sectional area of ​​the annular segment. This welding structure can effectively increase the welding area, improve the welding strength between the cover plate and the end shielding cover of the vacuum arc chamber, and avoid affecting the welding strength due to the need to set a very thin wall thickness for the annular segment of the cover plate.

[0008] Furthermore, the welding ring has an inner edge extending inwardly relative to the annular segment in the radial direction of the cover plate and an outer edge extending outwardly relative to the annular segment, and the welding surface of the welding ring includes a portion located on the inner edge and a portion on the outer edge.

[0009] Furthermore, the outer edge width of the welding ring is greater than the inner edge width.

[0010] Furthermore, the outer edge of the welding ring is flush with the radially outward side surface of the edge of the end shield.

[0011] Furthermore, the end shielding cover includes a shielding cover body and a transition ring welded and fixed between the shielding cover body and the outer shell.

[0012] Furthermore, the ring width of the transition ring is greater than the ring width of the welding ring.

[0013] Furthermore, the end shield includes an outwardly turned edge, on which a welding structure for welding with the end face of the shell is provided, and the outwardly turned edge is parallel to the end face of the shell and has a portion located radially inside the shell.

[0014] Furthermore, an inner edge of the end surface of the shell welded and fixed to the welding structure is provided with a chamfer.

[0015] Furthermore, the cover plate comprises a main body portion, one end of the annular segment away from the welding ring is connected to the main body portion, and the wall thickness of the main body portion is greater than the wall thickness of the annular segment.

[0016] Furthermore, the main body of the cover plate is provided with a curved structure spaced apart from the annular segment in the radial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A cross-sectional view of the fixing structure of the cover plate, the end shielding cover and the shell of the static end of the vacuum interrupter according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of a partial welding structure of an end shield, a cover plate and a housing; Figure 3 for Figure 2 Schematic diagram of the local structure of the welding ring of the cover plate.

[0018] In the figure: 1, outer shell; 2, cover plate; 21, ring segment; 22, welding ring; 220, inner edge; 221, outer edge; 23, groove; 24, bending structure; 3, end shielding cover; 30, shielding cover body; 31, outward edge; 32, transition ring. DETAILED DESCRIPTION

[0019] The basic concept of the present invention is to set a welding ring at the end of the annular segment of the cover plate of the vacuum arc chamber, and use the welding ring with a larger radial width to form a welding surface with a larger welding area, while ensuring that the annular segment of the cover plate is set with a very thin wall thickness and at the same time ensuring the welding strength between the cover plate and the end shielding cover.

[0020] The following is a specific description with reference to embodiments.

[0021] Embodiment of the vacuum interrupter of the present invention: The vacuum arc extinguishing chamber is columnar as a whole, with axial and radial directions. The two axial ends of the vacuum arc extinguishing chamber are respectively a static end and a dynamic end. Both the static end and the dynamic end are provided with a cover plate and an end shielding cover, that is, both have a welding structure in which the cover plate, the end shielding cover and the outer shell are welded and fixed. The welding structure of the static end is consistent with that of the dynamic end. The welding structure is specifically described in conjunction with the static end structure of the vacuum arc extinguishing chamber shown in the attached drawings of the specification.

[0022] like Figure 1 , Figure 2 , Figure 3 As shown, the vacuum interrupter includes a shell 1, an end shield 3 welded and fixed on the shell 1, and a cover plate 2 welded and fixed on the end shield 3. The cover plate 2 is made of stainless steel, and the shield is made of copper. The end shield and the cover are fixed at both ends of the shell 1. The end shield 3 is welded to the end face of the shell 1, and the part of the shell 1 for welding the end shield 3 is a metallized porcelain shell, which is formed by attaching a metal material layer on the porcelain material body, so that the metal layer on the end face of the shell 1 is welded to the end shield 3, thereby fixing the shell 1 and the end shield 3.

[0023] The cover plate 2 includes a main body and an axially extending annular segment 21, one end of the annular segment 21 is connected to the main body, and the other end is a terminal and is provided with a welding portion for welding with the end shield 3. In order to reduce the sealing stress between the cover plate 2 and the end shield 3, the wall thickness of the annular segment 21 of the cover plate 2 is very thin, and the welding seam sealing stress can be effectively reduced by deforming the annular segment 21 with a relatively thin wall thickness of the cover plate 2.

[0024] In order to ensure the deformation ability of the cover plate 2 while ensuring the welding strength of the cover plate 2 and the end shielding cover 3, the cover plate 2 also includes a welding ring 22 arranged at the end of the annular segment 21, and the welding ring 22 constitutes a welding portion for welding with the end shielding cover 3. One axial side surface of the welding ring 22 is connected to the annular segment 21, and the other side surface constitutes a welding surface for welding with the end shielding cover 3. The ring width of the welding ring 22 is greater than the wall thickness of the annular segment 21, so that the area of ​​the welding surface is greater than the cross-sectional area of ​​the annular segment 21. The welding ring 22 with a larger radial width can be used to form a welding surface with a larger welding area. This welding structure can effectively increase the welding area, improve the welding strength between the cover plate 2 and the end shielding cover 3 of the vacuum arc chamber, and avoid affecting the welding strength due to the need to set a very thin wall thickness for the annular segment 21 of the cover plate 2.

[0025] The ring width direction of the welding ring 22 of the cover plate 2 is consistent with its radial direction. The axial direction of the cover plate 2 is the axial direction of the welding ring 22. The cover plate 2 is coaxially arranged with the end shield 3 and the shell 1. The shell 1 is a tube body, and the cover plates 2 are arranged at the ends of the tube body for sealing. The welding ring 22 is coaxially arranged with the ring segment 21, and the axial thickness of the welding ring 22 can be set to be equal to the wall thickness of the ring segment 21. The ring width of the welding ring 22 is equal to the difference between half of the outer diameter and half of the inner diameter. The axial side surface of the welding ring 22 is perpendicular to the wall surface of the ring segment 21, and the welding ring 22 is integrally connected to the end of the ring segment 21. The inner diameter of the welding ring 22 is smaller than the inner diameter of the ring segment 21, and the outer diameter of the welding ring 22 is larger than the outer diameter of the ring segment 21. The axial size of the welding ring 22 is its thickness. The axial size of the welding ring 22 is much smaller than the axial size of the ring segment 21, and does not affect the deformation of the ring segment 21 to offset the welding stress.

[0026] The welding ring 22 has an inner edge 220 extending inward relative to the ring segment 21 in the radial direction of the cover plate 2 and an outer edge 221 extending outward relative to the ring segment 21. The welding surface of the welding ring 22 includes a portion located on the inner edge 220 and a portion on the outer edge 221. The side close to the vacuum cavity of the vacuum interrupter is the inner side, and the side facing away from the vacuum cavity of the vacuum interrupter is the outer side. The end of the ring segment 21 is connected to the middle area of ​​the welding ring 22 close to its ring width direction. The cross section of the ring segment 21 and the welding ring 22 forms a structure similar to a T shape. The side of the inner edge 220 abutting against the end shield 3 and the side of the outer edge 221 abutting against the end shield 3 are both used for welding with the end shield 3, which is conducive to reliable welding. The cover plate 2 is formed with welding fixing parts on both the inner and outer sides of the ring segment 21 in the radial direction, which is convenient for uniform force. In other embodiments, the ring segment can also be connected to the inner ring edge or the outer ring edge of the welding ring, and the cross section of the ring segment and the welding ring forms a structure similar to an L shape.

[0027] The width of the outer edge 221 of the welding ring 22 is greater than the width of the inner edge 220, and the width direction is consistent with the ring width direction, and the ring width direction is consistent with the radial direction. Under the condition of ensuring that the welding surface of the welding ring 22 has sufficient welding area, the welding area between the inner edge 220 and the end shielding cover 3 is smaller, and the welding area between the outer edge 221 and the end shielding cover 3 is larger, so that the bonding force between the outer edge 221 and the end shielding cover 3 is stronger. The end shield 3, the cover plate 2 and the shell 1 are brazed by a process in which brazing filler metal is filled between the corresponding joint surfaces. The end shield 3, the cover plate 2 and the shell 1 are heated in a furnace to melt the brazing filler metal and form a weld after cooling. The end shield 3 and the cover plate 2 have different shrinkage coefficients after cooling. The end shield 3 shrinks and generates stress after cooling. The shrinkage stress forms pressure on the end shield 3 through the inner edge 220 and forms tension on the end shield 3 through the outer edge 221. The pressure has little effect on the welding part, while the tension has a greater effect on the welding part. A relatively firm welding part is formed through the outer edge 221 with a larger width, which is conducive to reliable welding and avoids cracking. In other embodiments, the width of the inner edge can also be equal to the width of the outer edge.

[0028] The outer edge 221 of the welding ring 22 is flush with the radially outward side of the edge of the end shield 3, so that the welding ring 22 is as close to the outside as possible to avoid occupying the internal space of the vacuum interrupter, and at the same time, it is convenient to make the welding position of the end shield 3 and the welding ring 22, and the welding position of the end shield 3 and the shell 1 correspond in the axial direction, which is conducive to reliable fixation. In other implementations, the outer edge of the welding ring and the radially outward side of the edge of the end shield can also be staggered.

[0029] The end shield 3 includes a shield body 30 and a transition ring 32 welded and fixed between the shield body 30 and the end face of the shell 1. The transition ring 32 is made of copper and is coaxially arranged with the shield body 30. The shield body 30 is provided with an outward turning edge 31, which is an annular turning edge. The outward turning edge 31 is arranged parallel to and coaxial with the transition ring 32. One axial side of the outward turning edge 31 is connected to the welding ring 22, and the other side is connected to the transition ring 32. The transition ring 32 is arranged on the side of the outward turning edge 31 that is away from the welding ring 22. The radially outward circumferential side of the end of the outward turning edge 31 and the outer circumferential surface of the transition ring 32 together constitute the radially outward side of the edge of the end shield 3. The transition ring 32 constitutes a welding structure on the outward turning edge 31 for welding with the end face of the shell 1. Since the thickness of the shielding cover body 30 is too thin, a transition ring 32 is added to reduce welding stress. The thickness of the end shielding cover 3, the cover plate 2 and the shell 1 are increased by welding the transition ring 32 and the outer edge 31, thereby reducing welding stress and making the shielding cover body 30 have a smaller thickness. In other embodiments, the outer edge of the end shielding cover can also be directly welded and fixed to the end surface of the shell.

[0030] The outer circumference of the transition ring 32 is flush with the outer circumference of the welding ring 22, the thickness of the transition ring 32 is equal to the thickness of the outer edge 31, the ring width of the transition ring 32 is greater than the ring width of the welding ring 22, and the two axial side surfaces of the transition ring 32 can form a larger welding area, which is conducive to the stable welding with the shielding cover body 30 and the shell 1. Brazing material is filled between the axial side surface of the outer edge 31 of the end shielding cover 3 that faces away from the transition ring 32 and the corresponding side surface of the welding ring 22 of the cover plate 2, the transition ring 32 and the outer edge 31 are filled with solder, and the axial side surface of the transition ring 32 of the end shielding cover 3 that faces away from the outer edge 31 is filled with solder and fixed together by welding. In other embodiments, the ring width of the transition ring can also be equal to the ring width of the welding ring, or the ring width of the transition ring 32 is smaller than the ring width of the welding ring 22.

[0031] The outward-turned edge 31 is parallel to the end face of the shell 1 and has a portion radially located inside the shell 1. The ring width of the outward-turned edge 31 is much larger than the ring width of the transition ring 32. The bending position of the shielding cover body 30 to form the outward-turned edge 31 is located on the side of the shell 1 close to the axis. The outward-turned edge 31 is relatively wide, which is conducive to the deformation of the end shield 3. In other embodiments, the outward-turned edge can also be narrower, so that the bending position of the shielding cover body to form the outward-turned edge is radially located on the side of the inner wall of the shell away from the axis and on the axial side of the shell end face.

[0032] The inner and outer edges of the end face of the housing 1 are both chamfered, wherein the chamfer of the inner edge is inclined opposite to the bending position of the shielding cover body 30 to form the outer edge 31, thereby increasing the gap between the shielding cover body 30 and the end edge of the housing 1, which is conducive to uniform electric field. In other embodiments, no chamfer may be provided.

[0033] The end of the annular segment 21 of the cover plate 2 that is axially away from the welding ring 22 is integrally connected to its main body, and the wall thickness of the main body of the cover plate 2 is greater than the wall thickness of the annular segment 21. The wall thickness of the annular segment 21 is 0.7 mm, where the wall thickness is the material thickness, so that the wall thickness of the annular segment 21 is thinner and convenient for deformation when subjected to welding stress, and the wall thickness of the main body is thicker, so as to ensure the strength of the main body and avoid affecting the strength of the contact rod of the vacuum interrupter and the installation place of the cover plate 2. In other embodiments, the wall thickness of the main body of the cover plate can also be equal to the wall thickness of the annular segment as needed.

[0034] The main part of the cover plate 2 is bent at the junction with the annular segment 21 to form a curved transition structure, that is, the annular segment 21 is bent relative to the main part. The main part of the cover plate 2 is also provided with a curved structure 24 spaced apart from the annular segment 21 in the radial direction. The curved structure 24 is an annular structure that surrounds the center line of the cover plate 2. The curved structure 24 is concave inside and convex outside and protrudes toward the axial side of the cover plate 2. The apex of the curved structure 24 facing outward in the axial direction is flush with the apex of the curved transition structure facing outward in the axial direction. The outer edge of the curved structure 24 is bent through the curved part and extends to the curved transition structure to connect. The part of the cover plate 2 located near the axis of the curved structure 24 is a plane structure. The curved structure 24 is used to enclose the groove 23. The plane structure forms the groove bottom of the groove 23. The notch of the groove 23 faces outward in the axial direction. A mounting through hole for mounting the contact rod is provided at the center of the groove bottom of the groove 23. The curved structure 24 can enhance the strength of the main part of the cover plate 2, which is conducive to the reliable installation of the contact rod. In other embodiments, the above-mentioned curved structure may not be provided.

[0035] The welding structure of the vacuum interrupter has the advantages of simple structure, easy assembly and welding, which can effectively increase the welding area between the cover plate and the end shield, improve the welding strength of the weld, and at the same time maintain the 0.7mm thin-wall structure of the deformation part of the cover plate, which can effectively reduce the welding stress of the weld through the deformation of the parts themselves. It can be used in the production of power transmission grade vacuum interrupters, improve the welding strength of power transmission grade vacuum interrupters, and ensure the manufacturing yield rate of power transmission grade vacuum interrupters.

[0036] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vacuum interrupter, comprising a housing, an end shield welded and fixed to the housing, and a cover welded and fixed to the end shield, wherein the cover comprises an annular segment extending along its axial direction, wherein: The cover plate includes a welding ring arranged at the end of the annular segment, one axial side of the welding ring is connected to the annular segment, and the other side constitutes a welding surface for welding with the end shielding cover, and the ring width of the welding ring is greater than the wall thickness of the annular segment.

2. The vacuum interrupter according to claim 1, characterized in that: The welding ring has an inner edge extending inwardly relative to the annular segment in the radial direction of the cover plate and an outer edge extending outwardly relative to the annular segment. The welding surface of the welding ring includes a portion located on the inner edge and a portion on the outer edge.

3. The vacuum interrupter according to claim 2, characterized in that: The outer edge width of the welding ring is greater than the inner edge width.

4. The vacuum interrupter according to claim 2 or 3, characterized in that: The outer edge of the weld ring is flush with the radially outward side of the edge of the end shield.

5. The vacuum interrupter according to claim 1, 2 or 3, characterized in that: The end shielding cover comprises a shielding cover body and a transition ring welded and fixed between the shielding cover body and the shell.

6. The vacuum interrupter according to claim 5, characterized in that: The ring width of the transition ring is greater than the ring width of the welding ring.

7. The vacuum arc extinguishing chamber according to claim 1, 2 or 3 is characterized in that the end shielding cover includes an outward turning edge, on which a welding structure for welding to the end face of the outer shell is provided, and the outward turning edge is parallel to the end face of the outer shell and has a portion located radially inside the outer shell.

8. The vacuum interrupter according to claim 7, characterized in that: The inner edge of the shell end surface welded and fixed to the welding structure is provided with a chamfer.

9. The vacuum interrupter according to claim 1, 2 or 3, characterized in that: The cover plate comprises a main body part, one end of the annular segment away from the welding ring is connected to the main body part, and the wall thickness of the main body part is greater than the wall thickness of the annular segment.

10. The vacuum interrupter according to claim 9, characterized in that: The main body of the cover plate is provided with a curved structure spaced apart from the annular segment in the radial direction.

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