Single-piece shield manufactured by tension and compression molding

Abstract

The present invention proposes a single-piece shield for tubular insulators in high-voltage technology, manufactured by tension and compression molding, which does not require the manufacturing processes required for connecting its components by hard soldering or welding, as is the case with conventional multi-component shields.

Description

[Technical Field]

[0001] The present invention relates to shielding of insulators in high voltage technology.

[0002] In a vacuum interrupter, multiple interconnected insulators can form an insulating path. These insulators are connected to each other at the ends using a metal layer. This metal layer is conductive and shielded. Furthermore, one insulator may be connected to a metal part. This contact area is also shielded.

[0003] These shields consist of a flat cylindrical section to which the ends of the insulators are attached, above and below, and the shield extends axially along the edges of the cylindrical section, forming a thin cylinder or cone with a torus or partial torus at its ends.

[0004] The shield must act in both the positive and negative axial directions, i.e., it must act along the axis of the first insulator as well as along the axis of the second insulator. The shield is usually manufactured by tensile compressive forming (Zugdruckumformen). It is traditionally manufactured in several parts, which must be interconnected. This can be done by hard soldering or welding. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a shield for insulators in high voltage technology which requires reduced costs compared to conventional shields. [Means for solving the problem]

[0006] This problem is solved by a shield having the features of claim 1.

[0007] Compared to conventional multi-component shields, the single-piece shield of the present invention eliminates the manufacturing processes required for hard solder or welded connections, and by eliminating connections, the risk of hermetic solder failure is also eliminated.

[0008] Preferred developments of the invention are set forth in the dependent claims.

[0009] The present invention will now be described in more detail as an exemplary embodiment with reference to the drawings, to the extent necessary for understanding. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows a shield according to the invention between two insulators. [Figure 2] FIG. 2 shows a shield according to the invention between an insulator and a metal part. [Figure 3] Figure 3 shows a conventional two-component shield.

[0011] In these drawings, like names refer to like elements. DETAILED DESCRIPTION OF THE INVENTION

[0012] The conventional shield shown in FIG. 3, implemented in a two-part design, includes a first shield S1 with a flat, annular portion FA1. At the inner edge of this portion FA1, the shield extends toward axis A around a conical portion K1. A torus T1 or a portion of the torus T1 is connected to the end of the conical portion K1 toward axis A so that the cross section of the shield S1 approximates the shape of a question mark (?) and the torus T1 does not intersect with the plane of portion FA1. The first shield S1 and an identical second shield S2 are connected symmetrically to each other at their portions FA1 and FA2, which can be achieved, for example, by hard soldering or welding. Cylindrical insulators I1 and I2 are connected to the opposite planes of the portions FA1 and FA2.

[0013] The shield according to the invention, shown in FIG. 1 and implemented in a single piece, has a shield S with a flat annular portion FA. At the inner edge of the portion FA, the shield extends in the direction of the axis A around a conical portion K. A first surface GF1, curved towards the plane of the portion FA, is connected to the end of the conical portion K facing the axis A. The first surface GF1 is bent towards the axis A and has an arc-shaped cross section. A tubular portion RA with a substantially constant diameter is formed on the first surface GF1. A second surface GF2, curved towards the plane of the portion FA, is bent towards the axis A and has an arc-shaped cross section. The free end of the second curved surface GF2 faces the flat annular portion FA so as to leave an open gap SP. The conical portion K, the first curved surface GF1, the tubular portion RA, and the second curved surface GF2 form a not-completely-closed torus having an annular gap SP, which extends above and below the plane of the portion FA. The axis A of the tubular portion RA is perpendicular to the plane of the portion FA. The plane of the portion FA is perpendicular to the tubular portion RA. The upper and lower ends of the portion FA are connected to the end faces of tubular insulators I1 and I2, which are arranged concentrically about the axis A.

[0014] In the shield according to the invention shown in Figure 2, the shield S is of single-piece construction, similar to the shield S of Figure 1. Connected to the upper and lower sides of the portion FA are a tubular insulator I and a metal part MT, which are arranged concentrically about the axis A. The metal part MT has a thinner wall thickness than the insulator I.

[0015] The annularly extending gap SP in the torus of the shield S is oriented towards the metal part MT.

[0016] The shield S according to the invention is manufactured from one part, for example from a thin metal sheet, by tension-compression forming. In a first forming step, the first torus GF1 as well as a part of the torus is produced. In a subsequent forming step, the second torus GF2 as well as a part of the torus is produced.

[0017] The present invention has been described in detail with reference to specific embodiments for purposes of illustration, although elements of the individual embodiments may be combined with one another. Accordingly, the present invention should not be limited to the individual embodiments, but rather is limited only by the scope of the appended claims. [Explanation of symbols]

[0018] A...central axis, AB...spacing, FA1...flat portion of shield S1, FA2...flat portion of shield S2, GF1...first curved surface, GF2...second curved surface, K1...first conical portion, K2...second conical portion, I...insulator, I1...first insulator, I2...second insulator, MT...metal part, RA...tubular portion, S...shield, S1...first shield, S2...second shield, SP...gap, T1...torus 1, T2...torus 2, +...positive direction of axis A, -...negative direction of axis A

Claims

1. Shielding of insulators in high voltage technology, - one flat annular part (FA) concentric with the axis (A), - the inner edge of said part (FA) is formed with a conical part (K) which is inclined towards said axis (A) in the positive direction (+) of said axis (A), - a first surface (GF1) is formed at the end of the conical portion (K) and curved towards the axis (A) in the negative direction of the axis (A), the first surface (GF1) is bent concentrically around the axis (A) and has an arc-shaped cross section; - the end of said first curved surface (GF1) facing said axis (A) is formed with a tubular portion (RA) that is concentric with said axis (A) and has a substantially constant radius relative to said axis (A); the end of the tubular part (RA) oriented in the negative direction (-) of the axis (A) is formed with a second surface (GF2) curved towards the inner edge of the part (FA) in the positive direction (+) of the axis (A), said second surface (GF2) being bent concentrically around the axis (A) and having the shape of a circular arc in cross section; the radius of the free end of said curved surface (GF2), from said axis (A), is smaller than the radius of the inner edge of said portion (FA); the free end of the curved surface (GF2) in the negative direction (-) of the axis (A) has a distance (AB) from the plane of the portion (FA), - said plane of said portion (FA) is perpendicular to said tubular portion (RA); shield.

2. Shield according to claim 1, characterized in that said flat annular portion (FA) cooperates with an end face of the insulator (I).

3. 3. A shield according to claim 1 or 2, characterized in that said flat annular portion (FA) cooperates with an end face of a tubular metal part (MT).

4. 4. A shield according to claim 1, wherein the shield is manufactured from thin metal sheet by tension-compression forming.

5. Shield according to claim 1, characterized in that said first surface (GF1) is produced in a first moulding step and said second surface (GF2) is produced in a second moulding step.

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