Method for producing a hollow electrical insulator, hollow electrical insulator and use of the hollow electrical insulator

Abstract

A method for producing a hollow electrical insulator is provided, comprising the following steps: providing a core; winding a first winding layer (2) of a first fiber element onto the core; winding a second winding layer (7) of a second fiber element (8) onto an end region (10) of the core, wherein the first winding layer (2) comprises turns of the first fiber element, the turns of the first fiber element being at a first winding angle with respect to a main extension direction (R) of the core; the second winding layer (7) comprises turns (18) of the second fiber element (8), the turns of the second fiber element being at a second winding angle (α2) greater than the first winding angle with respect to the main extension direction (R) of the core, and the inner region (11) of the core being free of the second winding layer (7). In addition, a hollow electrical insulator and its use are provided.

Description

Field of the Invention

[0001] A method for manufacturing a hollow electrical insulator, a hollow electrical insulator, and an application of the hollow electrical insulator are provided. Background Art

[0002] For example, a method for manufacturing a hollow electrical insulator and a hollow electrical insulator are described in document WO 2011 / 026519 Al.

[0003] A hollow electrical insulator having increased strength and / or increased stiffness should be provided in at least one end region. In addition, a simplified method for manufacturing a hollow electrical insulator should be provided. Finally, a favorable application of the hollow electrical insulator should be given. Summary of the Invention

[0004] The object is achieved by a method having steps according to the invention, by a hollow electrical insulator having features according to the invention, and by an application according to the invention.

[0005] Favorable embodiments and further developments of the method, the hollow electrical insulator, and the application are given in the present invention.

[0006] According to an embodiment of the method for manufacturing a hollow electrical insulator, a core is provided. The core generally has an elongated shape. Preferably, the envelope of the core is rotationally symmetrically formed with respect to the rotation axis of the core. The envelope has, for example, the shape of a cylinder or an ellipsoid. In addition, the core preferably has a main extension direction extending parallel to the rotation axis of the envelope of the core.

[0007] According to another embodiment of the method, a first winding layer of a first fiber element is wound onto the core. For this purpose, the first fiber element is preferably guided onto the core by a fiber head. The fiber head or the core moves along the main extension direction of the core at a preferably constant speed, wherein the core rotates about its rotation axis at the same time, preferably also at a uniform speed. Preferably, the first winding layer is wound over the entire length of the core.

[0008] According to another embodiment of the method, a second winding layer of a second fiber element is wound onto the end region of the core. Here, the winding of the second winding layer onto the end region of the core is generally carried out as described in the foregoing scheme for the first winding layer.

[0009] The first and / or second fiber element preferably has a plurality of fibers or is formed by a plurality of fibers. Particularly preferably, the fibers of the first and / or second fiber element are glass, such as E-glass or are formed by E-glass. E-glass in particular relates to an aluminoborosilicate glass having less than 2% alkali oxide.

[0010] In addition, plastic fibers, such as polyester fibers or amide fibers, may also be suitable for the fiber element. Furthermore, the fibers of the fiber element can be pre-impregnated (English: "prepreg") with an uncured polymer resin. Here, the fibers are coated with an uncured resin, such as an epoxy resin. The first and / or second fiber element can be a fiber bundle or a roving.

[0011] Particularly preferably, the first fiber element and the second fiber element are configured identically. This has the advantage that there is no need to replace the fiber element on the fiber head between winding the first winding layer and winding the second winding layer.

[0012] Particularly preferably, the second winding layer of the second fiber element is wound only in the end region of the core body. The core body typically has two opposite end faces, wherein the end region of the core body adjoins one of the two end faces.

[0013] Preferably, the first winding layer has turns of the first fiber element, and the turns of the first fiber element form a first winding angle with the main extension direction of the core body. The second winding layer preferably has turns of the second fiber element, and the turns of the second fiber element form a second winding angle with the main extension direction of the core body. Here, the second winding angle is preferably greater than the first winding angle. Particularly preferably, the second winding angle is at least as large as twice the first winding angle. Preferably, the first winding angle is between 10° and 60° including 10° and 60°, particularly preferably between 20° and 54° including 20° and 54°. Preferably, the second winding angle is between 70° and 90° including 70° and 90°, particularly preferably between 80° and 90° including 80° and 90°.

[0014] The concept "turn" currently means the following section of the fiber element of the winding layer, which section completely surrounds the core body or the manufactured hollow electrical insulator once. Each winding layer typically has multiple turns or consists of multiple turns. Two directly adjacent turns of the winding layer preferably adjoin each other directly. The turns of the winding layer can all have the same winding angle. In addition, it is also possible that the winding angles of the turns of the winding layer are different.

[0015] In a particularly preferred embodiment of the method, the inner region of the core body does not have a second winding layer. Here, the inner region adjoins the end region. In other words, the second winding layer is particularly preferably applied only to the end region of the core body.

[0016] By means of the second winding layer applied only in the end region of the core body, mechanical reinforcement of the manufactured hollow electrical insulator can be advantageously achieved in the end region.

[0017] In another embodiment of the method, the first winding layer and the second winding layer are wound alternately with respect to each other. In other words, one or more first winding layers and one or more second winding layers are always wound alternately onto the core. In this way and method, the second winding layer can be integrated particularly well into the first winding layer.

[0018] Alternatively thereto, it is also possible that all second winding layers are first wound onto the end region of the core and thereafter all first winding layers are wound onto the entire length of the core in order to manufacture a hollow electrical insulator.

[0019] In another embodiment of the method, the second winding layer is wound from the end face of the core onto a smaller region of the end region with increasing number. In other words, each second winding layer preferably covers a smaller region starting from the end face of the core along the main extension direction than the preceding second winding layer. In particular, the second winding layer has fewer turns with increasing number. In this way and method, a particularly good strength of the end region of the manufactured hollow electrical insulator can be achieved.

[0020] In a particularly preferred embodiment of the method, the second winding layer is wound without using a turning mechanism. In other words, the core preferably has no turning mechanism when winding the second winding layer. The turning mechanism can for example relate to a bulge on the core or a pin, which is mounted in the end region or on the end face of the core and which prevents the turns from slipping off the core.

[0021] When using a turning mechanism, an interference volume of the wound fiber element is usually formed on the end of the core. Usually, the material of the interference volume is removed, for example by grinding. However, here the fibers of the fiber element are usually cut, thereby reducing the strength and / or stiffness of the manufactured hollow electrical insulator.

[0022] In particular, it is currently possible to apply the second winding layer of the second fiber element in the end region of the core without using a turning mechanism, since the second winding layer has a relatively large winding angle, which is preferably between 70° and 90° including 70° and 90°. Thus, the method can be simplified by reducing process steps and a hollow electrical insulator with improved mechanical stability can be achieved.

[0023] In another embodiment of the method, the first fiber element and / or the second fiber element are guided through a liquid matrix material before winding. The liquid matrix material is provided, for example, in a pool. The liquid matrix material usually relates to an unhardened polymer resin, for example an unhardened epoxy.

[0024] It is also possible, for example in the case of using vacuum and / or pressure, to introduce the base material into the first winding layer and / or the second winding layer after winding.

[0025] In one embodiment of the method, the base material is hardened, preferably at the end of the method. In this way, a mechanically stable hollow electrical insulator is achieved.

[0026] The method described here is suitable for manufacturing hollow electrical insulators. All features and embodiments currently described in connection with the method can thus also be incorporated in the hollow electrical insulator and vice versa.

[0027] In one embodiment, the hollow electrical insulator comprises a first winding layer of a first fiber element.

[0028] In another embodiment, the hollow electrical insulator comprises a second winding layer of a second fiber element in the end region of the hollow electrical insulator.

[0029] The hollow electrical insulator generally has a wall that defines an internal cavity. The first winding layer and the second winding layer are generally surrounded by the wall or form the wall.

[0030] Particularly preferably, the hollow electrical insulator has the shape of a cylinder or comprises a shape with an envelope having the shape of a cylinder. Particularly preferably, the shape of the hollow electrical insulator is rotationally symmetric with respect to the axis of rotation of the hollow electrical insulator. The axis of rotation of the hollow electrical insulator is preferably arranged parallel to the main extension direction of the hollow electrical insulator.

[0031] In another embodiment of the hollow electrical insulator, the first winding layer has turns of a first fiber element, and the turns of the first fiber element form a first winding angle with the main extension direction of the hollow electrical insulator.

[0032] In another embodiment of the hollow electrical insulator, the second winding layer has turns of a second fiber element, and the turns of the second fiber element form a second winding angle with the main extension direction of the hollow electrical insulator. Particularly preferably, the second winding angle is greater than the first winding angle, preferably at least twice as large. The first winding angle is preferably between 10° and 60° inclusive of 10° and 60°, particularly preferably between 20° and 54° inclusive of 20° and 54°. The second winding angle is preferably between 70° and 90° inclusive of 70° and 90°, particularly preferably between 80° and 90° inclusive of 80° and 90°.

[0033] Particularly preferably, the inner region of the hollow electrical insulator is free of a second winding layer. Thus, the second winding layer is preferably provided only in at least one end region of the hollow electrical insulator. However, it is also possible that the second end region of the hollow electrical insulator, which is opposite the first end region, is also provided with a second winding layer. The second winding layer constitutes a mechanical reinforcement in the end regions of the hollow electrical insulator. In this way and method, the strength and / or stiffness of the hollow electrical insulator in the end regions can be advantageously enhanced.

[0034] Furthermore, the second winding layer generally advantageously results in an increase in the wall thickness in the end regions of the hollow electrical insulator. This geometric change has advantageously caused an increased stiffness at least in the end regions.

[0035] Particularly preferably, the first winding layer and the second winding layer are arranged alternately with each other. Thus, the second winding layer can be integrated particularly well into the first winding layer, thereby improving the strength and / or stiffness of the hollow electrical insulator.

[0036] In a particularly preferred embodiment of the hollow electrical insulator, the number of the second winding layer to the outer surface of the hollow electrical insulator increases starting from the inner region of the hollow electrical insulator towards the end face. In other words, each second winding layer preferably covers a smaller area starting from the end face of the hollow electrical insulator along the main extension direction than the previous second winding layer. In particular, the second winding layer has fewer turns with an increasing number. In this way and method, particularly good strength of the end regions of the hollow electrical insulator can be achieved.

[0037] Particularly preferably, the wall of the hollow electrical insulator adjacent to the end face of the hollow electrical insulator has a greater thickness than the wall adjacent to the inner region. This can be achieved, for example, by the second winding layer having fewer turns with an increasing number. Correspondingly, the outer surface of the end region of the hollow electrical insulator, for example, has an inclined surface adjacent to the inner region.

[0038] Particularly preferably, the second winding layer of the hollow electrical insulator has no cut fibers, at least within the manufacturing tolerances. This currently particularly means that at least 90% and particularly preferably at least 95% of the fiber elements of the second winding layer have no cut fibers.

[0039] Particularly preferably, the hollow electrical insulator relates to a glass fiber-reinforced plastic tube (GFK tube).

[0040] The hollow electrical insulators described herein are particularly suitable for bushings in transformers. In the hollow electrical insulators proposed herein, the end regions of the hollow electrical insulators reinforced with a second winding layer can be used, in particular, for fastening by means of a flange. Hollow electrical insulators, especially those for bushings in transformers, often experience high mechanical loads in the end regions, which are mostly provided with flanges, due to bending loads or pressure loads based on internal gas pressure. As a result, the hollow electrical insulators may be temporarily deformed, thus affecting the connection to the flange (e.g., with an adhesive). Due to the reinforcement in the end region by the second winding layer, the end regions of the hollow electrical insulators can be loaded with higher mechanical loads, such as bending loads.

[0041] With the method proposed herein, hollow electrical insulators with high mechanical stability in the end regions can be advantageously achieved by method steps integrated into the winding process. Description of the Drawings

[0042] Further advantageous embodiments and refinements of the hollow electrical insulators and the method for manufacturing hollow electrical insulators result from the embodiments described hereinafter in conjunction with the drawings.

[0043] By means of Figures 1 to 3 a schematic illustration, the method for manufacturing a hollow electrical insulator according to a first embodiment is explained in more detail.

[0044] Figure 4 and 5 a schematic illustration shows a hollow electrical insulator according to an embodiment.

[0045] Figures 6 to 9 a schematic illustration shows a hollow electrical insulator according to a further embodiment. Detailed Description of the Embodiments

[0046] Identical, similar or functionally identical elements are provided with the same reference numerals in the respective figures. The dimensional ratios of the respective figures and the elements shown therein to one another are not considered to be to scale. Instead, the individual elements, in particular the layer thicknesses, may be shown much larger for better visibility and / or for better understanding.

[0047] In the method according to the Figures 1 to 3 embodiment, in a first step, a core body 1 (not shown) is provided. The core body 1 here has a shape including a rotationally symmetric envelope. The envelope has, for example, the shape of a cylinder or an ellipsoid. The envelope is rotationally symmetric with respect to the rotation axis R.

[0048] In the next step, turns 17 of a first fiber element 3 are wound onto the core body 1 ( Figure 1)。The first fiber element 3, for example, involves a bundle of glass fibers. For this purpose, the first fiber element 3 is guided by a fiber head 4, which moves along the main extension direction of the core body 1 (see arrow), and the main extension direction is arranged parallel to the rotation axis 8 of the core body 1.

[0049] Here, the core body 1 preferably rotates at a constant speed around the rotation axis R of the core body. In order to wind the first winding layer 2 of the first fiber element 3, for example, around the entire length of the core body 1, first, the first fiber element 3 is fastened to the core body 1. Then, the fiber head 4 moves from the end face 12 of the core body 1 along the main extension direction to the other end face of the core body 1. The turns 17 of the first fiber element 3 then form the first winding layer 2 on the core body 1. Now, multiple first winding layers 2 can be wound in the same manner and method.

[0050] The turns 17 of the first fiber element 3 of the first winding layer 2 have a first winding angle α1 with the main extension direction of the core body 1. Here, the first winding angle α1 is between 10° and 60°, including 10° and 60°.

[0051] The turns 17 of the first winding layer 2 can have different first winding angles α1 with the main extension direction ( Figure 3 ). In addition, it is also possible that the turns 17 of different first winding layers 2 have different first winding angles α1 with the main extension direction.

[0052] The core body 1 currently has an end region 10 and an inner region 11 directly connected to the end region 10. On the end face 12 of the core body 1, a turning mechanism 9, such as a pin, is currently provided. The turning mechanism 9 ensures that the turns 17 of the first fiber element 3 do not slide on the end face 12 of the core body 1.

[0053] Before the first fiber element 3 is guided onto the core body 1 by the fiber head 14, the first fiber element 3 currently passes through a bath 5, which has a liquid matrix material 6, such as epoxy resin. The first fiber element 3 is impregnated with the liquid matrix material 6 after passing through the bath 5.

[0054] In Figure 2 the next step schematically shown, the second winding layer 7 of the second fiber element 8 is wound on the end region 10 of the core body 1. The second winding layer 7 has turns 18 of the second fiber element 8, and the turns form a second winding angle α2 with the main extension direction of the core body 1. Here, the second winding angle α2 is greater than the first winding angle α1, for example, at least twice as large ( Figure 3)。Particularly preferably, the value of the second winding angle α2 lies between 70° and 90°, including 70° and 90°. Now, a plurality of second winding layers 7 can be applied one above the other. The individual turns 18 of the second winding layer 7 can have different second winding angles α2 with respect to the main extension direction. It is also possible that the turns 18 of different second winding layers 7 have different second winding angles α2 with respect to the main extension direction.

[0055] The second winding layer 7 of the second fiber element 8 is only wound in the end region 10 of the core body 1. The inner region 11 of the core body 1 does not have a second winding layer 7 here. It is also possible that the second winding layer 7 of the second fiber element 8 is also wound on a further end region.

[0056] Particularly preferably, in the method according to the Figures 1 to 3 embodiment, the turning mechanism 9 is only used on the end face 12 of the core body 1 when winding the first winding layer 2, while the second winding layer 7 is applied to the core body 1 without using the turning mechanism 9.

[0057] Now, one or more further first winding layers 2 of the first fiber element 3 and one or more further second winding layers 7 of the second fiber element 8 are wound onto the core body 1 in an alternating order.

[0058] Subsequently, the liquid matrix material 6 is hardened. In this way, a mechanically stable hollow electrical insulator is formed.

[0059] As shown, for example, by means of the Figure 4 perspective schematic view, the hollow electrical insulator according to the Figure 4 and 5 embodiment has an envelope including a cylindrical shape. The hollow electrical insulator is rotationally symmetric with respect to a rotation axis R extending parallel to the main extension direction of the hollow electrical insulator. The end region 10 of the hollow electrical insulator here at least partially has a larger cross-sectional area than the inner region 11 of the hollow electrical insulator.

[0060] The hollow electrical insulator has a wall 14 defining an inner space. The wall 14 of the hollow electrical insulator includes a first winding layer 2 and a second winding layer 7. In the inner region 11 of the hollow electrical insulator, the wall 14 only includes the first winding layer 2, while in the end region 10 of the hollow electrical insulator, the first winding layer 2 and the second winding layer 7 are arranged alternately. Here, the number of the second winding layer 7 to the outer surface 13 of the hollow electrical insulator increases starting from the inner region 11 towards the end face 12 of the hollow electrical insulator ( Figure 5 ).

[0061] In the hollow electrical insulator according to the Figure 6 and 7 embodiment, a flange 16 is mounted on the end face 12. Furthermore, in accordance withFigure 8 and 9 In the hollow electrical insulator of the embodiment of 9 , a shielding part 15, for example a silicone shielding part, is mounted on the outer surface 13 of the hollow electrical insulator. The hollow electrical insulator provided with the flange 16 and the shielding part 15 is particularly suitable for use as an insulating bushing (Durchführung) of a transformer.

[0062] The present invention is not limited to the description by means of the embodiments. Instead, the present invention includes any new features and any combination of features, which in particular includes any combination of the features contained in the present invention, even if the feature or the combination itself is not explicitly given in the present invention or the embodiments.

[0063] List of reference numerals

[0064] 1 Core

[0065] 2 First winding layer

[0066] 3 First fiber element

[0067] 4 Fiber head

[0068] 5 Pool

[0069] 6 Matrix material

[0070] 7 Second winding layer

[0071] 8 Second fiber element

[0072] 9 Steering mechanism

[0073] 10 End region

[0074] 11 Inner region

[0075] 12 End face

[0076] 13 Outer surface

[0077] 14 Wall

[0078] 15 Shielding part

[0079] 16 Flange

[0080] 17 Turns of the first fiber element

[0081] 18 Turns of the second fiber element

[0082] α1 First winding angle

[0083] α2 Second winding angle

[0084] R Axis of rotation

Claims

1. A method for manufacturing a hollow electrical insulator, comprising the following steps: Providing a core (1), winding a first winding layer (2) of a first fiber element (3) onto the core (1), winding a second winding layer (7) of a second fiber element (8) onto the end region (10) of the core (1), The first winding layer (2) comprises turns (17) of a first fiber element (3), the turns of the first fiber element forming a first winding angle (α1) with respect to the main extension direction of the core (1), The second winding layer (7) comprises turns (18) of a second fiber element (8), the turns of the second fiber element being arranged at a second winding angle (α2) greater than the first winding angle (α1) with respect to the main extension direction of the core (1), and The inner region (11) of the core (1) is free of the second winding layer (7), winding the second winding layer (7) without using a steering mechanism (9), Each winding layer has a plurality of turns, each turn (17) of the first winding layer (2) forms a different first winding angle (α1) with respect to the main extension direction, and each turn (18) of the second winding layer (7) forms a different second winding angle (α2) with respect to the main extension direction, A plurality of first winding layers (2) and second winding layers (7) are applied, wherein the turns (17) of different first winding layers (2) form different first winding angles (α1) with respect to the main extension direction, and the turns (18) of different second winding layers (7) form different second winding angles (α2) with respect to the main extension direction.

2. The method according to claim 1, wherein: The first winding layers (2) and the second winding layers (7) are wound alternately with each other.

3. The method according to claim 1 or 2, wherein: The second winding layers ( 7 ) are wound in increasing numbers starting from the end face ( 12 ) of the core ( 1 ) onto a smaller area of ​​the end region ( 10 ).

4. The method according to claim 1 or 2, wherein: The first fiber element (3) and / or the second fiber element (8) are guided through a liquid matrix material (6) before being wound up.

5. The method according to claim 1 or 2, wherein: The first winding angle (αl) is between 10° and 60° and includes 10° and 60°, and / or The second winding angle (α2) is between 70° and 90°, inclusive.

6. Hollow electrical insulators, comprising: a first wound layer (2) of a first fiber element (3), and a second winding layer (7) of a second fiber element (8) in the end region (10) of the hollow electrical insulator, The first winding layer (2) comprises turns (17) of a first fiber element (3), the turns of the first fiber element being arranged at a first winding angle (α1) with respect to a main extension direction of the hollow electrical insulator, The second winding layer (7) comprises turns (18) of a second fiber element (8), the turns of the second fiber element being arranged at a second winding angle (α2) with respect to the main extension direction of the hollow electrical insulator, which is greater than the first winding angle (α1), and The inner region (11) of the hollow electrical insulator is free of the second winding layer (7), in, winding the second winding layer (7) without using a steering mechanism (9), Each winding layer has a plurality of turns, each turn (17) of the first winding layer (2) forms a different first winding angle (α1) with respect to the main extension direction, and each turn (18) of the second winding layer (7) forms a different second winding angle (α2) with respect to the main extension direction, A plurality of first winding layers (2) and second winding layers (7) are applied, wherein the turns (17) of different first winding layers (2) form different first winding angles (α1) with respect to the main extension direction, and the turns (18) of different second winding layers (7) form different second winding angles (α2) with respect to the main extension direction.

7. The hollow electrical insulator according to claim 6, wherein: The first winding layers (2) and the second winding layers (7) are arranged alternately.

8. A hollow electrical insulator according to claim 6 or 7, wherein: Starting from the outer surface (13) of the hollow electrical insulator, the number of the second winding layers (7) increases from the inner region (11) to the end face (12) of the hollow electrical insulator.

9. The hollow electrical insulator according to claim 6 or 7, wherein: The second winding layer (7) does not contain cut fibers.

10. A hollow electrical insulator according to claim 6 or 7, wherein: The first winding angle (αl) is between 10° and 60° and includes 10° and 60°, and / or The second winding angle (α2) is between 70° and 90°, inclusive.

11. Use of the hollow electrical insulator according to any one of claims 6 to 10 for insulating bushings in transformers.

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