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 multiple mechanically stiff supporting elements (9), each produced from an insulating material. Each supporting element (9) is connected to both base elements (3, 5) and surrounds the vacuum interrupter (7) around parts of the circumference and in a contactless manner. The supporting elements (9) are arranged spaced apart from one another around the vacuum interrupter (7) and surrounded by an electrically non-conductive elastomer (13), which fills the intermediate spaces between the supporting elements (9) and between the supporting elements (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, as known, for example, from DE 10 2016 218 316 A1, are circuit breakers in which switching contact elements that can be moved relative to one another are arranged in the vacuum interrupter in order to avoid or reduce a switching arc when the switching contact elements are separated. 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 in the housing to be arranged closer together, thus saving installation space. Such vacuum switches are relatively complex and expensive due to the pressurized insulating gas and, moreover, are inoperable 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 vacuum interrupter housing, making this design only suitable for relatively small vacuum interrupters where the forces occurring are so small that they do not damage the vacuum interrupter.

[0003] 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.

[0004] The object is achieved according to the invention by a vacuum switch having the features of claim 1.

[0005] Advantageous embodiments of the invention are the subject of the dependent claims.

[0006] A vacuum interrupter according to the invention comprises two spaced-apart base elements, a vacuum interrupter arranged between the base elements, and several mechanically rigid support elements, each made of an insulating material. Each support element is connected to both base elements and partially surrounds the vacuum interrupter in a contact-free manner. The support elements are arranged spaced apart around the vacuum interrupter and surrounded by an electrically non-conductive elastomer that fills the spaces between the support elements and between the support elements and the vacuum interrupter.

[0007] The invention combines a multi-part support structure of the vacuum interrupter formed by the support elements with an electrically non-conductive elastomer that surrounds the support elements. The support elements impart mechanical strength to the vacuum interrupter by connecting the base elements of the vacuum interrupter to one another. Furthermore, the support elements contribute to the dielectric strength, which in other vacuum interrupter designs is achieved by a pressurized insulating gas and / or a plastic encasing the vacuum interrupter. Because the support elements surround the vacuum interrupter without contact and at a distance from one another and are only connected to the vacuum interrupter via the elastomer, virtually no forces are transferred from the support elements to the vacuum interrupter. Temperature changes do lead to volume changes in the elastomer.However, these are dissipated to the outside through the gaps between the support elements and therefore generate only minimal stresses on the vacuum interrupter. Figuratively speaking, the elastomer can "breathe" through the gaps between the support elements.

[0008] Furthermore, because the vacuum interrupter has a plurality of support elements distributed around the vacuum interrupter, the support elements can be mounted individually, and their shape can be adapted to the shape of the vacuum interrupter, so that each support element has a substantially constant distance from the vacuum interrupter over its entire length. A one-piece, tubular support element, on the other hand, would have to have a minimum inner diameter that is larger than a maximum outer diameter of the vacuum interrupter in order to be able to mount the support element around the vacuum interrupter. As a result, in a vacuum interrupter with a varying outer diameter, the distance of the support element from the vacuum interrupter would vary along the vacuum interrupter, so that a wall thickness and thus the mechanical and dielectric strength of the shell formed by the support element and the elastomer around the vacuum interrupter would vary.Furthermore, more elastomer would be required to fill the space between the vacuum interrupter and the support element due to the varying distance, which can significantly increase the cost of the vacuum interrupter, since suitable elastomers are usually relatively expensive.

[0009] The invention thus creates an insulating-gas-free vacuum interrupter in which hardly any forces from a supporting 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 supporting elements, 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 elements to a base element.

[0011] In a further embodiment of the vacuum switch, the support elements are connected to the base elements by screw connections and / or adhesive connections. Screw connections can be implemented, for example, by threaded bushings incorporated into the support elements, enabling a detachable connection between the support elements 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 elements. In particular, the outer surface formed by the elastomer can have several shield-like surface areas extending concentrically around the support elements. 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, each 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 elements, as they allow for relatively easy production of support elements 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] At least one support element has at least one recess filled with the elastomer. Recesses in the support elements, like the spaces between the support elements, serve to dissipate volume changes of the elastomer to the outside, thus preventing or reducing stresses on the vacuum interrupter.

[0018] In a further embodiment of the vacuum switch, at least one recess in a support element has an oval shape. Oval shapes also include shapes with partially straight edges, such as a "racetrack" shape. Oval-shaped recesses avoid dielectrically unfavorable corners of the recesses and enable a suitable compromise between the mechanical and dielectric strength of the support element.

[0019] 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.

[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 elements. Areas of the support elements exposed to particularly strong local loads can, of course, have greater wall thicknesses than the remaining areas.

[0021] In a further embodiment of the vacuum interrupter, each support element has a shape corresponding to the vacuum interrupter, so that the support element has a substantially constant distance from the vacuum interrupter. This advantageously makes it possible to achieve a uniform wall thickness and thus a uniform mechanical and dielectric strength of the casing formed by the support element and the elastomer around the vacuum interrupter. Furthermore, the amount of elastomer required to manufacture the vacuum interrupter can be advantageously minimized by minimizing the distance between the support elements and the vacuum interrupter and thus the gaps to be filled with the elastomer.

[0022] In a method according to the invention for producing a vacuum switch according to the invention, the support elements are first mounted around the vacuum interrupter 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 1 shown vacuum switch in a pre-assembled state without elastomer, FIG 3 a perspective view of a support element of the in Figure 1 shown vacuum switch, FIG 4 a sectional view of a second embodiment of a vacuum switch, FIG 5 the in Figure 4shown vacuum switch in a pre-assembled state without elastomer, FIG 6 a perspective view of a support element of the Figure 4 shown vacuum switch, FIG 7 a sectional view of a third embodiment of a vacuum switch, FIG 8 a sectional view of a fourth embodiment of a vacuum switch, FIG 9 a sectional view of a fifth embodiment of a vacuum switch, FIG 10 the in Figure 9 shown vacuum switch in a pre-assembled state without elastomer, FIG 11 a sectional view of a sixth embodiment of a vacuum switch, FIG 12 the in Figure 11 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 two mechanically rigid support elements 9, each of which is connected to both base elements 3, 5. Each support element 9 surrounds the vacuum interrupter 7 almost halfway around and without contact, and is made of an insulating material. The support elements 9 are arranged at a distance from one another around the vacuum interrupter 7, so that together they surround the vacuum interrupter 7 in a tubular manner with slots 10 running between them.The support elements 9 are surrounded by an electrically non-conductive elastomer 13 which fills the spaces between the support elements 9 forming the slots 10 and between the support elements 9 and the vacuum interrupter 7 and forms an outer surface 15 of the vacuum switch 1 which extends around the support elements 9.

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

[0028] FIG 3 (FIG 3 ) shows a perspective view of a support element 9 of the Figure 1 shown vacuum switch 1.

[0029] 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.

[0030] 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.

[0031] 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, to which the ends of both support elements 9 are fastened by screw connections. For this purpose, threaded bushings 12 for receiving a respective screw element are introduced (for example, cast into) the ends of the support elements 9.The fastening flange 33 of the first base element 3 is arranged near the first end region 19 of the vacuum interrupter 7, the fastening flange 35 of the second base element 5 is arranged near the second end region 21 of the vacuum interrupter 7.

[0032] The two support elements 9 extend between the fastening flanges 33, 35 along the vacuum interrupter 7. Each support element 9 has a shape corresponding to the vacuum interrupter 7, so that the support element 9 has a substantially constant distance from the vacuum interrupter 7. In particular, each support element 9 widens in a central section 9.1 corresponding to the central region 17 of the vacuum interrupter 7, relative to side sections 9.2, 9.3 adjoining the central section 9.1 on both sides, which correspond to the insulation regions 23, 25 of the vacuum interrupter 7. Each side section 9.2, 9.3 is adjoined by an end section 9.4, 9.5 of the support element 9, into which threaded bushings 12 are introduced and which, for this purpose, has a greater wall thickness than the central section 9.1 and the side sections 9.2, 9.3.The supporting elements 9 are made, for example, of a plastic, a fiber-plastic composite or a ceramic material.

[0033] The elastomer 13 is, for example, a silicone elastomer. The outer surface 15 formed by the elastomer 13 has several umbrella-like surface regions 37 extending concentrically around the support elements 9.

[0034] To manufacture the vacuum switch 1, the support elements 9 are first mounted around the vacuum interrupter 7 and connected to the base elements 3, 5. Figure 2 shows the thus pre-assembled vacuum switch 1. The pre-assembled vacuum switch 1 is then cast with the elastomer 13 in a casting mold, whereby the spaces between the support elements 9 and between the support elements 9 and the vacuum interrupter 7 are filled with the elastomer 13 and the outer surface 15 of the vacuum switch 1 is formed.

[0035] Figure 4 (FIG 4) shows a sectional view of a second embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 1 The first embodiment shown differs only in that each support element 9 has a plurality of recesses 11. Recesses 11 are arranged in the central section 9.1 and the two side sections 9.2, 9.3 of the support element 9. The recesses 11 each have an oval shape with straight edges in sections and are each filled with the elastomer 13.

[0036] Figure 5 (FIG 5 ) shows analogous to Figure 2 the in Figure 4 shown vacuum switch 1 in a pre-assembled state without the elastomer 13.

[0037] Figure 6 (FIG 6 ) shows a perspective view of a support element 9 of the Figure 4 shown vacuum switch 1.

[0038] Figure 7 (FIG 7) shows a sectional view of a third embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 1shown first 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 1 In the first 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.

[0039] Figure 8 (FIG 8 ) shows a sectional view of a fourth embodiment of a vacuum switch 1. This embodiment differs from that shown in Figure 7shown embodiment in that the shielding region 31 of the first base element 3 projects 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 7 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 elements 9 extend in contrast to the embodiment shown in Figure 7 shown embodiment up to the end of the first base element 3 remote from the vacuum interrupter.

[0040] The Figure 9 and 10 ( FIG 9 and FIG 10) show a fifth embodiment of a vacuum switch 1. This embodiment differs from that shown in the Figures 4 to 6 The embodiment shown is characterized by the design of the support elements 9. The support elements 9 do not widen in their central sections 9.1 compared to their side sections 9.2, 9.3, but rather each have a constant outer diameter over their entire length. Furthermore, each support element 9 has only two recesses 11 arranged one behind the other in the longitudinal direction. Figure 9 shows a sectional view of the vacuum switch 1. Figure 10 shows analogous to Figure 5 the in Figure 9 shown vacuum switch 1 in a pre-assembled state without the elastomer 13.

[0041] The Figure 11 and 12 ( FIG 11 and FIG 12 ) show a sixth embodiment of a vacuum switch 1. This embodiment differs from that shown in the Figure 9 and 10shown embodiment 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 11shows a sectional view of the vacuum switch 1. Figure 12 shows analogous to Figure 5 the in Figure 11 shown vacuum switch 1 in a pre-assembled state without the elastomer 13.

[0042] The characteristics of the Figures 1 to 12 The embodiments of a vacuum switch 1 shown can be combined with each other to form further embodiments. In particular, the Figure 7 and 8 shown embodiments can be modified in that their support elements 9 have recesses 11 analogous to those shown in the Figure 5 , 10 or 12 shown supporting elements 9. Furthermore, the Figure 9 and 10 The embodiment shown can be modified in that the support elements 9 are designed without recesses 11.

[0043] 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 - multiple mechanically rigid support elements (9), wherein - each support element (9) is connected to both base elements (3, 5), extends without contact around part of the circumference of the vacuum interrupter (7) and is made of an insulating material, and - the support elements (9) are arranged spaced apart from one another around the vacuum interrupter (7) and are surrounded by an electrically non-conductive elastomer (13) which fills the gaps between the support elements (9) and between the support elements (9) and the vacuum interrupter (7), characterized in that at least one support element (9) has at least one clearance (11) which is filled with the elastomer (13).

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 elements (9).

3. Vacuum switch (1) according to Claim 1 or 2, wherein each support element (9) is connected to the base elements (3, 5) by way of screw connections and / or adhesive connections.

4. Vacuum switch (1) according to one 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).

5. Vacuum switch (1) according to Claim 4, 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.

6. Vacuum switch (1) according to Claim 4 or 5, 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.

7. 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).

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

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

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

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

12. Vacuum switch (1) according to Claim 11, wherein at least one clearance (11) in a support element (9) is formed by a cutout (11.1) in a main body (9.6) of the support element (9), in which cutout there is arranged at least one filling body (9.7) of the support element (9) that is connected to the main body (9.6) by an elastic web (9.8).

13. Vacuum switch (1) according to one of the preceding claims, wherein each support element (9) has a shape which corresponds to the vacuum interrupter (7), so that the support element (9) is at a substantially constant distance from the vacuum interrupter (7).

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

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