Vacuum switch

Abstract

The invention relates to a vacuum switch (1). The vacuum switch (1) comprises two spaced-apart base elements (3, 5), a vacuum interrupter (7) arranged between the base elements (3, 5) and a mechanically stiff supporting element (9), which is produced from an insulating material. The supporting element (9) is connected to both base elements (3, 5), surrounds the vacuum interrupter (7) like a tube and in a contactless manner, and has multiple recesses (11). The supporting element (9) is also surrounded by an electrically non-conductive elastomer (13), which fills the recesses (11) in the supporting element (9) and fills an intermediate space between the supporting element (9) and the vacuum interrupter (7).

Description

[0001] The invention relates to a vacuum switch with two spaced-apart base elements and a vacuum interrupter arranged between the base elements.

[0002] Such vacuum switches are circuit breakers in which switching contact elements that can be moved relative to one another are arranged in the vacuum interrupter, as known, for example, from CN 201 796 808 U, in order to avoid or reduce a switching arc when the switching contact elements are separated.

[0003] Another design is known from DE10 2016 218 316 A1. This shows a vacuum switch with two spaced-apart base elements, with a vacuum interrupter arranged between the base elements and a plurality of support elements connected to both base elements. The support elements surround the vacuum interrupter and are made of an insulating material. The support elements are surrounded by an electrically non-conductive elastomer that fills the spaces between the support elements and a space between the support elements and the vacuum interrupter. In one known design of vacuum switch, the vacuum interrupter is arranged within an electrically insulating housing in an insulating gas that is compressed under high pressure to increase its dielectric strength. This allows for the metallic components to be arranged closer together in the housing, thus saving installation space.Such vacuum interrupters are relatively complex and expensive due to the pressurized insulating gas, and they also fail to function if the pressure drops. In another vacuum interrupter design, the vacuum interrupter is alternatively or additionally encased in a plastic that replaces or supplements the dielectric function of the insulating gas. However, with this design, forces, particularly forces resulting from temperature changes, are transferred from the plastic to the housing of the vacuum interrupter, making this design only suitable for relatively small vacuum interrupters where the forces generated are so small that they do not damage the vacuum interrupter.

[0004] The invention is based on the object of providing a vacuum switch which is improved in particular with regard to its functional reliability and the reduction of forces acting on the vacuum interrupter.

[0005] The object is achieved according to the invention by a vacuum switch having the features of claim 1.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] A vacuum interrupter according to the invention comprises two spaced-apart base elements, a vacuum interrupter arranged between the base elements, and a mechanically rigid support element made of an insulating material. The support element is connected to both base elements, surrounds the vacuum interrupter in a tubular, contact-free manner, and has a plurality of recesses. Furthermore, the support element is surrounded by an electrically non-conductive elastomer that fills the recesses in the support element and a gap between the support element and the vacuum interrupter.

[0008] The invention combines a mechanically rigid support element of the vacuum switch with an electrically non-conductive elastomer that surrounds the support element. The support element imparts mechanical strength to the vacuum switch by connecting the base elements of the vacuum switch to one another. Furthermore, the support element contributes to the dielectric strength, which in other vacuum switch designs is achieved by a pressurized insulating gas and / or a plastic encasing the vacuum interrupter. Because the support element surrounds the vacuum interrupter without contact and is only connected to the vacuum interrupter via the elastomer, virtually no forces are transferred from the support element to the vacuum interrupter. Temperature changes do lead to volume changes in the elastomer, but these are dissipated outwards through the recesses in the support element and therefore generate only low stresses on the vacuum interrupter.Figuratively speaking, the elastomer can “breathe” through the recesses in the support element.

[0009] The invention thus realizes an insulating gas-free vacuum interrupter in which hardly any forces from a support structure are transferred to the vacuum interrupter, making it suitable for large vacuum interrupters. The insulating gas-free design eliminates, in particular, components for gas monitoring, pressure sealing systems, and pressure vessel components. A vacuum interrupter according to the invention can also be easily designed for various requirements by appropriately designing the support element, in particular, to achieve specific shield geometries, creepage distances, thicknesses, and / or flashover distances.

[0010] In one embodiment of the vacuum switch, at least one base element has a mounting flange connected to the support element. This enables a simple and convenient connection of the support element to a base element.

[0011] The support element is connected to the base elements by screw connections and / or adhesive joints. Screw connections can be realized, for example, by threaded bushings incorporated into the support element, enabling a detachable connection between the support element and the base elements.

[0012] In a further embodiment of the vacuum switch, the vacuum interrupter is connected to a first base element, and a movable switching contact element of the vacuum interrupter extends into the second base element. The first base element thus supports the vacuum interrupter. For example, the vacuum interrupter can be arranged on the first base element via a fixed (non-movable) switching contact element, which has an end extending from the vacuum interrupter and connected to the first base element. For example, components of a mechanism for moving the movable switching contact element can be arranged in the second base element.

[0013] In a further embodiment of the vacuum interrupter, the first base element has a shielding region that surrounds an end region of the vacuum interrupter facing the first base element in a shield-like manner, and a hollow cylindrical region or bolt-like solid cylindrical region adjoining the shielding region on the side remote from the vacuum interrupter. In a further embodiment of the vacuum interrupter, the second base element is essentially designed as a hollow cylinder into which an end region of the vacuum interrupter facing the second base element projects. The base elements can thus contribute to shielding electric fields at the end regions of the vacuum interrupter.

[0014] In a further embodiment of the vacuum switch, the vacuum switch has an outer surface formed by the elastomer, which extends around the support element. In particular, the outer surface formed by the elastomer can have several shield-like surface regions extending concentrically around the support element. In these embodiments of the vacuum switch, the elastomer is advantageously also used to form the outer surface of the vacuum switch, in particular to form insulating shields to extend creepage paths for leakage currents along the outer surface of the vacuum switch.

[0015] In a further embodiment of the vacuum switch, the elastomer is a silicone elastomer. Silicone elastomers are UV-resistant and therefore particularly suitable for forming the outer surface of the vacuum switch.

[0016] In a further embodiment of the vacuum switch, the support element is made of a plastic, a fiber-plastic composite, or a ceramic material. Plastics and fiber-plastic composites are preferred materials for the manufacture of the support element, as they allow for relatively easy production of a support element with a suitable shape and the required mechanical and dielectric properties. Ceramic material can also be used, but is relatively brittle and heavy and is therefore generally less preferred.

[0017] In a further embodiment of the vacuum switch, at least one recess in the support element has an oval shape. Oval shapes also include shapes with partially straight edges, such as a "racetrack" shape. Oval recesses avoid dielectrically unfavorable corners and enable a suitable compromise between the mechanical and dielectric strength of the support element.

[0018] In a further embodiment of the vacuum switch, at least one recess in a support element is formed by a cutout in a base body of the support element, in which at least one filler body of the support element is arranged, which is connected to the base body by an elastic web. The elasticity of the web allows the filler body to be movable relative to the base body. This allows the filler body embedded in the elastomer to move relative to the base body when the volume of the elastomer changes, particularly as a function of temperature. Despite the filler body, the elastomer can therefore "breathe" through the cutout in the base body. The filler body saves elastomer, which can reduce the manufacturing costs of the vacuum switch, since the material from which the support elements are made is generally cheaper than the elastomer.

[0019] In a further embodiment of the vacuum switch, the support element has a grid-like structure. A support element with a grid-like structure is understood here to be a support element whose recesses are relatively evenly distributed. This enables uniform loading of the support element without critical load areas and allows for even dissipation of volume changes in the elastomer through the recesses.

[0020] In a further embodiment of the vacuum switch, the support element has a substantially constant wall thickness. This advantageously avoids load-critical areas of the support element with very thin wall thicknesses and a varying dielectric strength of the support element. Areas of the support element that are subject to particularly strong local loads can, of course, have greater wall thicknesses than the remaining areas.

[0021] In a further embodiment of the vacuum switch, the support element is shaped such that the vacuum interrupter can be pushed into the support element. This allows the vacuum switch to be installed by pushing the vacuum interrupter into the support element or by sliding the support element over the vacuum interrupter.

[0022] In a method according to the invention for producing a vacuum switching switch according to the invention, the support element is mounted around the vacuum interrupter and connected to the base elements and then cast with the elastomer in a casting mold.

[0023] This allows the elastomer to be easily applied after pre-assembly of the other components of the vacuum switch in a mold into which the pre-assembled vacuum switch is inserted.

[0024] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. FIG 1 a sectional view of a first embodiment of a vacuum switch, FIG 2 the Figure 1shown vacuum switch in a pre-assembled state without elastomer, FIG 3 a sectional view of a second embodiment of a vacuum switch, FIG 4 a sectional view of a third embodiment of a vacuum switch, FIG 5 a sectional view of a fourth embodiment of a vacuum switch, FIG 6 a sectional view of a fifth embodiment of a vacuum switch, FIG 7 a sectional view of a sixth embodiment of a vacuum switch, FIG 8 a sectional view of a seventh embodiment of a vacuum switch, FIG 9 the in Figure 8 The vacuum switch shown is pre-assembled without elastomer.

[0025] Corresponding parts are provided with the same reference numerals in the figures.

[0026] Figure 1 (FIG 1 ) shows a sectional view of a first embodiment of a vacuum switch 1.The vacuum switch 1 comprises two spaced-apart base elements 3, 5, a vacuum interrupter 7 arranged between the base elements 3, 5 and a mechanically rigid support element 9 , which is connected to both base elements 3, 5. The support element 9 surrounds the vacuum interrupter 7 in a tubular and contact-free manner, is made of an insulating material, and has a plurality of recesses 11. The support element 9 is surrounded by an electrically non-conductive elastomer 13, which fills the recesses 11 in the support element 9, the spaces between the support element 9 and the vacuum interrupter 7, and between the support element 9 and the base elements 3, 5, and forms an outer surface 15 of the vacuum switch 1 that extends around the support element 9.

[0027] Figure 2 (FIG 2 ) shows the Figure 1 shown vacuum switch 1 in a pre-assembled state without the elastomer 13.

[0028] The vacuum interrupter 7 has a metallic central region 17, two metallic end regions 19, 21, and two insulating regions 23, 25. The central region 17 has a larger diameter than the end regions 19, 21 and the insulating regions 23, 25 and is arranged between the insulating regions 23, 25. The insulating regions 23, 25 are each made of an electrically non-conductive material. A first end region 19 protrudes into the first base element 3 and adjoins a first insulating region 23. The second end region 21 protrudes into the second base element 5 and adjoins the second insulating region 23.

[0029] Two electrically conductive switching contact elements 27, 29 are arranged in the vacuum interrupter 7. A first switching contact element 27 is firmly connected to the first end region 19 of the vacuum interrupter 7. An end of the first switching contact element 27 leading out of the vacuum interrupter 7 is connected to the first base element 3, for example by a screw connection (not shown). The vacuum interrupter 7 is thereby connected to the first base element 3. The second switching contact element 29 is movable by a mechanism (not shown) relative to the first switching contact element 27 between a first switching position, in which the switching contact elements 27, 29 touch, and a Figure 1 shown second switching position, in which the switching contact elements 27, 29 are spaced apart from one another. One end of the second switching contact element 29 is led out of the vacuum interrupter 7 through an opening in the second end region 21.

[0030] The base elements 3, 5 are each made of a metal, for example aluminum, or an alloy. Each base element 3, 5 is essentially designed as a hollow cylinder, with an end of the first base element 3 facing the vacuum interrupter 7 being designed as a shield region 31 that closes the hollow cylinder region 39 on the vacuum interrupter side and surrounds the first end region 19 of the vacuum interrupter 7 in a shield-like manner. The end of the first switching contact element 27 leading out of the vacuum interrupter 7 is arranged centrally on the shield region 31. Furthermore, each base element 3, 5 has an outwardly projecting fastening flange 33, 35, which forms an end of the base element 3, 5 facing away from the vacuum interrupter 7 and is connected to one end of the support element 9, for example by screw connections (not shown) and / or an adhesive connection.

[0031] The support element 9 connects the two base elements 3, 5 to one another and surrounds the vacuum interrupter 7 and the base elements 3, 5 up to their fastening flanges 33, 35. The support element 9 has the shape of a hollow cylinder, the cylinder wall of which has the recesses 11. A central section of the support element 9 surrounding the vacuum interrupter 7 has a plurality of recesses 11, each of which extends substantially along the entire longitudinal extent of the vacuum interrupter 7, wherein the longitudinal extent is understood to mean the extent of the vacuum interrupter 7 between its end regions 19, 21. Furthermore, each end section of the support element 9 also has a plurality of recesses 11 in the region of a respective base element 3, 5.Each recess 11 has two edges running parallel to a longitudinal axis of the vacuum switch 1, which are connected to each other by curved edges, so that the recess 11 has an oval shape ("racetrack shape") composed of the straight and curved edges. Overall, the support element 9 has a grid-like structure. The support element 9 is made, for example, of a plastic, a fiber-plastic composite, or a ceramic material.

[0032] The elastomer 13 is, for example, a silicone elastomer. To manufacture the vacuum switch 1, the support element 9 is first mounted around the vacuum interrupter 7 and connected to the base elements 3, 5. For example, the support element 9 is pushed over the vacuum interrupter 7 and the first base element 3 and connected to the fastening flange 33 of the first base element 3. Then, the second base element 5 is pushed into the support element 9, and the fastening flange 35 of the second base element 5 is connected to the support element 9. Alternatively, the support element 9 can be connected analogously first to the second base element 5 and then to the first base element 3. Figure 2shows the thus pre-assembled vacuum switch 1. The pre-assembled vacuum switch 1 is then cast with the elastomer 13 in a casting mold, wherein the recesses 11 in the support element 9 and the spaces between the support element 9 and the vacuum interrupter 7 and between the support element 9 and the base elements 3, 5 are filled with the elastomer 13 and the outer surface 15 of the vacuum switch 1 is formed.

[0033] Figure 3 (FIG 3 ) shows a sectional view of a second embodiment of a vacuum switch 1. This embodiment differs from the one shown in the Figure 1 and 2 shown first embodiment only in that the outer surface 15 formed by the elastomer 13 has several umbrella-like surface areas 37 extending concentrically around the support element 9. Compared to the Figure 1 and 2In the first embodiment shown, creepage paths for leakage currents along the outer surface 15 are thereby advantageously extended.

[0034] Figure 4 (FIG 4 ) shows a sectional view of a third embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 3shown second exemplary embodiment, on the one hand, in that the fastening flange 33 of the first base element 3 is arranged near the first end region 19 of the vacuum interrupter 7 and the fastening flange 35 of the second base element 5 is arranged near the second end region 21 of the vacuum interrupter 7. The support element 9 thus extends essentially only around the vacuum interrupter 7. In addition, a first section of the support element 9 running around the first insulation region 23 has a smaller diameter than a second section running around the second insulation region 25 and an adjacent section of the central region 17. In other words, the support element 9 widens from the first section to the second section, so that the support element 9 can only be pushed over the vacuum interrupter 7 in the direction from the first end region 19 to the second end region 21.The outer surface 15 of the vacuum switch 1 formed by the elastomer 13 around the support element 9 also expands accordingly. Furthermore, the support element 9 has recesses 11 in the first section and in the second section. Compared to the one shown in . Figure 2 In the embodiment shown, the support element 9 is thus shorter and its first section has a smaller distance from the vacuum interrupter 7, whereby material, in particular expensive elastomer material, can be saved and thus the material costs for the vacuum switch 1 can be reduced.

[0035] Figure 5 (FIG 5 ) shows a sectional view of a fourth embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 4shown third embodiment by the design of the first base element 3. Away from the vacuum interrupter 7, the shielding region 31 of the first base element 3 is not adjoined by a hollow cylinder region 39 but by a bolt-like solid cylinder region 41 which has a smaller diameter than the shielding region 31. The solid cylinder region 41 can comprise at least one screw which runs through this region in order to fasten the first switching contact element 27 to the first base element 3. In other words, the first base element 3 can have a base body through which at least one screw is guided in the longitudinal direction into the first switching contact element 27. In this case, the base body in the solid cylinder region 41 is therefore not designed as a solid cylinder, but has at least one bore for a screw.Together with the at least one screw, the base body then essentially forms a solid cylinder in the solid cylinder region 41. However, the first switching contact element 27 can also be connected to the first base element 3 in another way, for example by welding or shrinking. In this case, the solid cylinder region 41 can be designed as a solid, one-piece solid cylinder. Compared to the solid cylinder shown in . Figure 4 In the third embodiment shown, the smaller diameter of the first base element 3 in the solid cylinder area 41 saves material for the first base element 3 and for the elastomer 13 and the weight of the vacuum switch 1 is reduced.

[0036] Figure 6 (FIG 6 ) shows a sectional view of a fifth embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 5shown embodiment in that the shielding region 31 of the first base element 3 protrudes obliquely from the solid cylinder region 41 towards the vacuum interrupter 7 and has a central region 43 extending the solid cylinder region 41 on the vacuum interrupter side, on which the end of the first switching contact element 27 leading out of the vacuum interrupter 7 is arranged. As in the Figure 5 In the embodiment shown, the solid cylinder region 41 can comprise at least one screw that runs through this region in order to fasten the first switching contact element 27 to the first base element 3. Furthermore, the support element 9 extends in contrast to the embodiment shown in Figure 5 shown embodiment up to the ends of both base elements 3, 5 away from the vacuum interrupter. In this embodiment too, compared to the embodiment shown in Figure 4In the third embodiment shown, material for the first base element 3 and for the elastomer 13 is saved and the weight of the vacuum switch 1 is reduced.

[0037] Figure 7 (FIG 7 ) shows a sectional view of a sixth embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 3 shown embodiment only in that the second base element 5 is shorter than the first base element 3 and the vacuum tube 7 is not arranged centrally in the vacuum switch 1.

[0038] The Figure 8 and 9 ( FIG 8 and FIG 9 ) show a seventh embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 4shown embodiment essentially only by the design of the recesses 11 in the support elements 9. Each recess 11 in a support element 9 is formed by an oval cutout 11.1 in a base body 9.6 of the support element 9, in which at least one filler body 9.7 of the support element 9 is arranged, which is connected to the base body 9.6 by a web 9.8. Each web 9.8 is narrow and therefore elastic, so that the filler body 9.7 connected by it to the base body 9.6 is movable relative to the base body 9.6. As a result, the filler bodies 9.7 embedded in the elastomer 13 can move relative to the base bodies 9.6 when the volume of the elastomer 13 changes, in particular depending on temperature. The filler elements 9.7 save elastomer 13, which allows the manufacturing costs for the vacuum switch 1 to be reduced, since the material from which the support elements 9 are made is generally cheaper than the elastomer 13.. Figure 8 shows a sectional view of the vacuum switch 1. Figure 9 shows analogous to Figure 2 the in Figure 8 shown vacuum switch 1 in a pre-assembled state without the elastomer 13.

[0039] Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

1. Vacuum switch (1) comprising - two base elements (3, 5) which are spaced apart from one another, - a vacuum interrupter (7) which is arranged between the base elements (3, 5), and - a mechanically rigid support element (9), which is connected to both base elements (3, 5), tubularly and contactlessly surrounds the vacuum interrupter (7), is made from an insulating material and has multiple apertures (11), wherein - the support element (9) is surrounded by an electrically non-conductive elastomer (13), which fills the apertures (11) in the support element (9) and an intermediate space between the support element (9) and the vacuum interrupter (7), and wherein the support element (9) is connected to the base elements (3, 5) by screw connections and / or adhesive bonds.

2. Vacuum switch (1) according to Claim 1, wherein at least one base element (3, 5) has a fastening flange (33, 35) which is connected to the support element (9).

3. Vacuum switch (1) according to either of the preceding claims, wherein the vacuum interrupter (7) is connected to a first base element (3), and a movable switching contact element (29) of the vacuum interrupter (7) projects into the second base element (5).

4. Vacuum switch (1) according to Claim 3, wherein the first base element (3) has a shielding region (31), which surrounds an end region (19), facing towards the first base element (3), of the vacuum interrupter (7) in the manner of a shield, and a hollow cylinder region (39) or pin-like solid cylinder region (41), which adjoins the shielding region (31) remotely from the vacuum interrupter.

5. Vacuum switch (1) according to Claim 3 or 4, wherein the second base element (5) is substantially in the form of a hollow cylinder, into which an end region (21), facing towards the second base element (5), of the vacuum interrupter (7) projects.

6. Vacuum switch (1) according to one of the preceding claims, having an outer surface (15) which is formed by the elastomer (13) and which extends around the support element (9).

7. Vacuum switch (1) according to Claim 6, wherein the outer surface (15) formed by the elastomer (13) has multiple shield-like surface regions (37) which extend concentrically around the support element (9).

8. Vacuum switch (1) according to one of the preceding claims, wherein the elastomer (13) is a silicone elastomer.

9. Vacuum switch (1) according to one of the preceding claims, wherein the support element (9) is made of a plastic or a fibre-plastic composite or a ceramic material.

10. Vacuum switch (1) according to one of the preceding claims, wherein at least one aperture (11) in the support element (9) has an oval shape.

11. Vacuum switch (1) according to one of the preceding claims, wherein at least one aperture (11) in a support element (9) is formed by a cutout (11.1) which is in a main body (9.6) of the support element (9) and in which there is at least one filling body (9.7) of the support element (9), this filling body being connected to the main body (9.6) by an elastic bridging element (9.8).

12. Vacuum switch (1) according to one of the preceding claims, wherein the support element (9) has a lattice-like structure.

13. Vacuum switch (1) according to one of the preceding claims, wherein the support element (9) is shaped in such a way that the vacuum interrupter (7) can be pushed into the support element (9).

14. Method for producing a vacuum switch (1) according to one of the preceding claims, wherein the support element (9) is fitted around the vacuum interrupter (7) and connected to the base elements (3, 5) and then encapsulated with the elastomer (13) in a casting mould.

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