Method for manufacturing a winding end support, winding end support, and electromechanical device

Abstract

The present invention relates to a method for manufacturing a winding end support for a rotor (1) of a rotating electrical machine. To simultaneously enable the manufacture of particularly large winding end supports in a simple manner, it is contemplated according to the invention that the winding end support is formed using additive manufacturing methods, in particular by arc wire build-up welding. The present invention further relates to a winding end support.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a winding end support (Wickelkopfabstuetzung) for a rotor of a rotating electrical machine.

[0002] The present invention further relates to a winding end support for a rotor of an electrical machine.

Background Art

[0003] Winding end supports for rotors of electrical machines and methods for manufacturing the same are known from the prior art. Such winding end supports are provided to absorb the centrifugal force acting on the winding ends of the rotor based on rotation, thereby avoiding unacceptable deformation of the winding ends. Winding end supports of the prior art are typically formed of high-strength materials, in particular high-strength non-magnetizable steel, and often have one or two rings, as described, for example, in Austrian Patent Application Publication No. 508622, and the corresponding rings are typically formed by forging and rolling and, in some cases, by another method to achieve particularly high strength.

[0004] However, such winding end supports can only be formed up to a maximum size predetermined by a given rolling device. Furthermore, the maximum size of such a winding end support is also limited by the transport route from the manufacturing facility to the location where the electrical machine will be operated, usually a power plant. Therefore, to date, winding end supports can only be manufactured up to a maximum inner diameter of about 6 m, and thereby the winding end support can also be a limiting factor in machine design.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention starts from this. The object of the present invention is to provide a method of the kind described at the beginning that can manufacture a winding end support independently of the limitations predetermined by forging or rolling devices.

[0006] Such a winding end support is also further provided.

Means for Solving the Problems

[0007] The first problem is solved, according to the invention, by a method of the kind described at the beginning, in which the winding end support is formed by an additive manufacturing method (additives Herstellungsverfahren), in particular by wire arc surfacing welding (Lichtbogendraht-Auftragsschweissen).

[0008] Within the scope of the present invention, it has been recognized that surprisingly high strength can also be achieved with objects manufactured by additive manufacturing methods. Therefore, there is no need for equipment for forging and rolling to form the winding end support, and thus it is not necessary to always carry out the manufacturing in a manufacturing facility having forging or rolling equipment. Therefore, it is possible to manufacture the corresponding winding end support even on site, for example, at the location where a power plant is being constructed.

[0009] Basically, a very diverse range of additive manufacturing methods can also be used to form the corresponding winding end support, for example, a welding method using a laser or a submerged arc welding method (Unterpulverschweissverfahren). However, it has been found that it is particularly advantageous when the winding end support is formed by wire arc surfacing welding. Such a manufacturing method is also called wire-arc additive manufacturing. In that case, by the selection of the corresponding wire, the properties of the winding end support can be easily influenced. In order to achieve a non-magnetizable and at the same time high-strength winding end support, a wire that can usually achieve an austenitic structure in the formed weld seams or the winding end support in the corresponding manner is used.

[0010] In principle, such a winding head support can also be formed by segments that are individually detachably connected to each other, but preferably, it is contemplated that the winding end support is formed in a ring shape. Therefore, it is preferred that the corresponding winding end support has one or more rings that can stabilize the winding ends of the rotor. The corresponding ring-shaped winding end support can be easily formed, for example, by a plurality of ring-shaped welded joints connected to each other, and subsequently, it can be arranged outside or inside the winding ends to support the winding ends against centrifugal force.

[0011] Basically, the winding end support can also be formed by any material that achieves the mechanical, thermal, and magnetic properties required by each machine, that is, plastic, ceramic, or the like. However, when a fully austenitic structure is formed by an additive manufacturing method, the required properties can be easily achieved with high reliability at the same time.

[0012] The winding end support can basically also be formed, for example, by a 3D printing method or a sintering method in which metal powder particles are bonded to each other. However, in order to achieve particularly high strength, the winding end support is formed by welding a plurality of layers of metal, and the welded layers preferably have a completely austenitic structure. In that case, the metal is preferably continuously supplied to the welded joint as a wire. Therefore, usually, a winding end support formed as a ring or having one or more rings is manufactured layer by layer by applying a plurality of overlapping welded joints, and the individual welded joints are usually formed in a circular or ring shape. The completely austenitic structure of the formed ring or the formed winding end support is particularly advantageous for use in an electromechanical device based on magnetic properties.

[0013] A particularly simple manufacturing method is achieved when the winding end support is formed by applying a material to a moving support element, especially one that rotates about a rotation axis.

[0014] For example, a welding apparatus in which a winding end support is formed by arc wire build-up welding can easily form even a ring with a very large diameter, even if it is only slightly moved to apply the weldment to different radial and axial positions of the ring. Therefore, when a supporting element that can be arranged, for example, on a rotating platform is appropriately moved, it is not necessary to move the welding apparatus over the circumference of the ring. Thereby, an apparatus for manufacturing the corresponding winding end support can be formed very simply and inexpensively. Furthermore, it enables the production of a ring or a ring-shaped winding end support with high precision.

[0015] The supporting element can basically be formed from the same material as the winding end support. However, it can also be contemplated that the supporting element is formed from another material, for example, a material with lower strength than the winding end support. In this case, in order to achieve a homogeneous winding end support, it can be contemplated that the winding end support is removed from the supporting element after the formation of at least one layer of the winding end support, particularly after the manufacture of the winding end support. Therefore, the winding end support thus formed is preferably connected to the supporting element made of metal in a material-bonded manner.

[0016] Therefore, in order to remove the winding end support from the supporting element, it can be cut from the supporting element, for example.

[0017] A high-strength winding end support is achieved when the winding end support is formed by arranging a plurality of layers connected in a material-bonded manner in an overlapping manner. This can be easily done by applying a plurality of weld seams in an overlapping manner, and the individual weld seams are preferably formed from the same material. Therefore, a layer can comprise one weld seam, or a plurality of weld seams arranged side by side and / or in an overlapping manner. The layer extends over the entire cross-section of the winding end support to be manufactured, for example, over the entire cross-section of the ring, and has a height of less than 10 cm, particularly less than 5 cm. This ensures a stable and layered structure of the winding end support.

[0018] In this context, it is advantageous if first the inner and outer boundaries of the layer are formed and then the layer is formed by filling the space between the inner and outer boundaries with material. In particular, in order to achieve a round winding end support or a winding end support with particularly low unbalance, the ring formed by the corresponding build-up welding can, of course, be further processed, for example by turning, milling or grinding, before use in an electromechanical device, where the inner boundary forms the inner diameter of the ring forming the winding end support and the outer boundary can form the outer shape of this ring.

[0019] It has been found to be effective to first form the inner and outer boundaries of the layer in order to achieve a high speed of manufacture of the winding end support at a favorable temperature during production of the layer. At the same time, by filling the region between the inner and outer boundaries, it is possible to easily achieve a material with high strength and homogeneity and without welding joint defects such as pores and voids.

[0020] Normally, after forming the inner and outer boundaries, in order to achieve a consistent layer between the inner and outer boundaries, the space between the inner and outer boundaries is filled with further weld seams starting from the outer boundary. After forming the inner and outer boundaries, it is also conceivable that first one or two weld seams are arranged adjacent to the inner or outer boundary and then further weld seams are arranged starting from the outer or inner boundary in order to fill the space between the inner and outer boundaries. Thereby, it is achieved that the weld seams to which further adjacent weld seams are provided are already slightly cooled, minimizing the risk of cracks during the welding process. One layer can have, for example, a height of 2 to 5, in particular 3, superimposed weld seams.

[0021] In order to achieve a high homogeneity and strength of the winding end support, it is preferably contemplated that the formation of the winding end support is carried out using a protective gas in order to avoid an oxide layer in the winding end support.

[0022] When the winding end support is formed of steel having a chromium equivalent of 6% to 32%, particularly 10% to 28%, and especially 18% to 24%, the advantageous mechanical and magnetic properties of the winding end support can be easily achieved.

[0023] The chromium equivalent is calculated as follows. Chromium equivalent = %Cr + %Mo + 1.5%Si + 0.5%Nb. Furthermore, in order for the winding end support to achieve advantageous mechanical and magnetic properties, it has been found that it is advantageous when formed of steel having a nickel equivalent of 10% to 40%, particularly 16% to 32%, and especially 24 to 29%. The nickel equivalent of the steel is calculated as follows. Nickel equivalent = %Ni + 30%C + 0.5%Mn Instead of or in addition to this, it can also be contemplated that austenitic Mn steel or austenitic Mn-N steel is used.

[0024] The corresponding steel is usually applied as a wire by the arc wire build-up welding method to form the winding end.

[0025] Since such steel shows a high tendency to hot cracking, another layer or the layer or support element to which a weld joint is applied is cooled to a temperature of less than 1,250°C, particularly preferably less than 500°C, especially less than 100°C, before a new layer or a new weld joint is applied. Therefore, it is advantageous if the production is carried out by cooling the already formed part of the winding end support.

[0026] Cooling can basically be carried out in a very diverse manner. Cooling is particularly efficient when a fluid such as a gas or a liquid, particularly air, CO 2 or water is applied to the already formed part of the winding end support and / or to the body thermally connected to the winding end support, particularly by using a nozzle, and the fluid has a lower temperature than the formed part of the winding end support.

[0027] For example, a cold fluid can be directly applied to the formed part of the winding end support, particularly to the formed weld seam, to cool this part.

[0028] Alternatively or in addition to this, for cooling purposes, it can also be contemplated that the winding end support is arranged on a platform during manufacturing, and the platform is cooled, particularly by a fluid, especially water. Thus, for example, a platform that moves, particularly rotates, to easily form an annular winding end support can conductively cool the winding end support arranged on the platform and connected to it by surface contact. For this purpose, the platform can be arranged, for example, in a water bath or can be provided with cooling pipes through which water flows to cool the platform during operation. Naturally, instead of or in addition to the conductive cooling of the winding end support, a fluid can be applied, particularly to the formed part of the winding end support, to cool the platform.

[0029] To achieve particularly advantageous mechanical properties, the formed part of the winding end support is heat-treated after the execution of the additive manufacturing method. The heat treatment can include, particularly for a part or all of the winding end support, solution annealing, quenching, and / or stress relief annealing. For example, to achieve advantageous corrosion resistance and reduce internal stress, the part of the winding end support formed by the additive manufacturing method, particularly the formed ring, can be heat-treated by solution annealing the part and quenching it with water, and then, optionally, further stress relief annealing is performed.

[0030] To achieve particularly precisely defined dimensions, it can be advantageous if the formed part of the winding end support is subjected to a cutting manufacturing method, particularly turning, milling, and / or grinding, after the execution of the additive manufacturing method. Thereby, particularly small unbalances in, for example, the ring-shaped part of the winding end support can also be achieved.

[0031] When the winding end support or a part thereof is heat-treated as described above, the heat treatment is usually carried out before the winding end support or a part thereof is subjected to the cutting manufacturing method. Thereby, within the range of the heat treatment, for example, shape changes that may occur due to thermal expansion can also be compensated within the range of the cutting process.

[0032] Another problem is solved according to the present invention by a winding end support of the type mentioned at the beginning, the winding end support being formed by an additive manufacturing method, in particular by the method according to the present invention.

[0033] Normally, the corresponding winding end support is made of an austenitic, in particular non-magnetizable material.

[0034] Preferably, it is contemplated that the winding end support is formed as a ring or has one or more rings that can be easily attached to the winding end.

[0035] With the method according to the present invention, basically, winding end supports can be formed in any size, whereby they can be used, for example, for generators in large-scale hydroelectric power plants. Usually, such winding end supports comprise rings having an inner diameter exceeding 1 m, in particular exceeding 4 m, especially exceeding 6 m.

[0036] In an electric machine comprising a stator and a rotor, wherein the rotor has at least one winding end on one side and a winding end support is provided to receive the centrifugal force generated during operation, it is advantageous if the winding end support is formed according to the present invention. Thereby, even a large electric machine can be formed with a winding end support relatively easily outside of conventional manufacturing facilities. Such an electric machine can be formed, for example, as an asynchronous generator and can be used in a hydroelectric power plant.

[0037] Such a machine preferably has an inner ring and an outer ring formed by the method according to the invention at each winding end. In that case, the outer ring is shrink-fitted onto the winding end, and it is also possible to form a combined body with the inner ring of the machine and the winding rod in the region of the winding end according to the Austrian Patent Application Publication No. 508622.

[0038] Other features, advantages, and effects of the present invention will become apparent based on the embodiments described below. The drawings referred to are as follows.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0040] FIG. 1 shows a rotor 1 of an electric machine, which is formed here as an asynchronous machine and can be used as a motor or a generator in a hydroelectric power plant. The rotor 1 has a rotor shaft and a rotor laminated core 3 in which rotor windings are arranged. The rotor windings protrude beyond the rotor laminated core 3 at the end sides, thereby forming winding ends. In order to support the winding ends against the centrifugal force generated by the rotation of the rotor about the rotation axis 4 during operation, a ring-shaped winding end support is provided. The winding end support has an outer ring and an inner ring, and only the outer ring 2 can be seen in FIG. 1. The basic structure of the winding end support having an outer ring 2 and an inner ring is known, for example, from the specification of Austrian Patent Application Publication No. 508622.

[0041] According to the present invention, the winding end support, or the inner ring and / or the outer ring 2 of the corresponding winding end support, is no longer formed by forging, rolling, or in some cases, cold hardening as known from the prior art, but is manufactured using an additive manufacturing method.

[0042] FIG. 2 shows an apparatus 7 for carrying out the method according to the present invention, in which a ring-shaped winding end support is formed by arc wire build-up welding using a welding apparatus 8 shown schematically. The apparatus 7 has a platform 5 that can be rotated about a rotation axis 12 using a drive apparatus (not shown), and a ring-shaped winding end support that can be used, for example, as the outer ring 2 of the electric machine shown in FIG. 1 is formed by providing a plurality of weld seams along the circumferential direction on a carrier element 6. The carrier element 6 is detachably arranged on the platform. The carrier element 6 can likewise be manufactured in such a way or can consist of another material that can only be connected to the welds provided. In the latter case, it can be contemplated that the carrier element 6 is separated from the winding end support after the manufacture of the winding end support.

[0043] After rotating the platform 5 about the axis of rotation 12, it is sufficient for the welding device 8 to be moved axially and radially relative to the axis of rotation 12 only within the range necessary to form the radial and axial extensions of the winding end support. Thus, by rotating the platform 5 together with the support element 6 about the axis of rotation 12, a circumferential movement of the welding device 8 about the axis of rotation 12 is not necessary, and therefore, using such a device 7, a very large ring 14 with an inner diameter exceeding, for example, 6 m can be easily formed by slightly moving the welding device 8. Such a device 7 can be easily assembled and can therefore basically be assembled even where electromechanics are used. Thereby, the production of the winding end support is also possible on site, thereby eliminating the limitation of the maximum size of the winding end support based on the transport route.

[0044] To achieve a winding end support having an austenitic structure, it is preferable to use a steel with a chromium equivalent of 16% to 24% and a nickel equivalent of 22% to 29% as the wire for forming the winding end support, usually by the arc wire build-up method. Instead of this, another austenitic steel, particularly austenitic Mn steel, or austenitic Mn-N steel can also be used. Such steels are both high-strength and have magnetically advantageous properties for the winding ends of electromechanics. Since such materials also exhibit a high tendency to crack at high temperatures, it is preferably contemplated that the winding end support be cooled during its formation.

[0045] For this purpose, cooling can be carried out with a fluid, particularly air, CO 2 , or water or steam, which is applied to the already formed part of the winding end support or the formed ring 14 of the winding end support, and this part is cooled by convection. To enable the heat to be discharged from the ring 14 in a simple manner, as shown in FIG. 3, a housing 9 that partially covers the ring 14 can be provided.

[0046] Furthermore, it can also be contemplated that the area where the ring 14 is manufactured is always maintained at a low temperature by a heat exchanger. In this case, preferably, it is contemplated that the manufacturing of the winding end support is carried out within the closed housing 9. This is schematically shown in FIG. 4. As can be seen here, the connection parts for the heat exchanger arranged inside the ring, that is, the forward path 10 and the return path 11 for the medium, for example water, which are arranged within the housing and are sent through a heat exchanger not shown here, protrude from the housing 9.

[0047] Alternatively, or in addition to this, it can also be contemplated that the apparatus 7 for carrying out the manufacturing is cooled. For example, the platform 5 on which the ring 14 is formed can be cooled with a liquid such as water. This is exemplarily shown in FIG. 5, where the platform 5 is surrounded by a water bath 13. Also in this case, the forward path 10 and the return path 11 are provided to enable continuous supply of cold water to the water bath 13 and derivation of the heated water from the water bath 13.

[0048] Naturally, it is also possible that the platform 5, and thus here exemplarily the ring 14, is provided with cooling pipes 18 in order to cool the winding end support arranged on the platform 5. This is schematically shown in FIG. 6. Also in this case, the forward path 10 and the return path 11 are provided to ensure the flow through the cooling pipes 18.

[0049] In FIGS. 5 and 6, the inner diameter 19 of the correspondingly manufactured ring 14 of the winding end support can also be seen. In the case of the ring 14 manufactured according to the present invention, since the manufacturing method is independent of the forging apparatus or the transportable method, it is also possible without problem for the inner diameter to exceed 6 m.

[0050] FIG. 7 shows a detail of a cross-section through the ring 14 of a winding end support formed according to the invention for an asynchronous motor, arranged on the support element 6, and also shows the welding seams W1, W2, W3, W4, W5, W6, W7, W8, W9, W10, W11, W12, W13, W14 of the layer 17 of the ring 14. The winding end support formed according to the invention usually has a plurality of layers 17, and only the lowermost layer 17 arranged on the support element 6 is shown in FIG. 7. Each layer 17 has an inner boundary 15 and an outer boundary 16 between which further welding seams W7, W8, W9, W10, W11, W12, W13, W14 are arranged, and here extends in a direction normal to the axis of rotation 12 over the entire cross-section of the ring 14.

[0051] When producing the layer 17 of the ring 14 shown in FIG. 7, first, three inner welding seams W1, W2, W3 forming the inner boundary 15 of the lowermost layer 17 are formed, and then three outer welding seams W4, W5, W6 forming the outer boundary 16 of the layer 17 are formed. Of course, when manufacturing the ring 14 using the device 7 according to FIG. 1, the distance of the outer boundary 16 from the axis of rotation 12 is greater than that of the inner boundary 15. After forming the inner boundary 15 and the outer boundary 16, subsequently, the space remaining between the inner boundary 15 and the outer boundary 16 is filled with the lowermost welding seams W7, W8, W9, W10, with the lower outer welding seam W7 being applied first adjacent to the outer boundary 16, then another lower welding seam W8 being applied adjacent to the lower outer welding seam W7, then the lower inner welding seam W9 being applied adjacent to the inner boundary 16, and finally the last lower welding seam W10 being applied between the lower inner welding seam W9 and another lower welding seam W8.

[0052] Subsequently, upper welding seams W11, W12, W13, W14 are arranged on the lower welding seams W7, W8, W9, W10, starting at the inner boundary 15, with the upper inner welding seam W11 being applied first, then another upper inner welding seam W12, and then, starting from the outer boundary 16, another welding seam W13 and W14 being applied, filling the space between the outer boundary 16 and the inner boundary 15.

[0053] Subsequently, another layer 17 is formed on the lowermost layer 17 shown in FIG. 7 in the corresponding order. FIG. 8 shows a cross-section passing through the ring 14 formed in this way, and it can be seen from the ascending reference numerals of the individual weld seams W1 to W110 the order in which the individual weld seams W1 to W110 are assigned.

[0054] Of course, basically another order in which the weld seams W1 to W110 are assigned is also possible, but the corresponding order results in a particularly stable pore-free and void-free structure of the corresponding ring 14 based on the advantageous temperature during manufacturing.

[0055] To avoid an oxide layer that would be disadvantageous for the strength of the winding end support, the weld seams are usually applied under a protective gas.

[0056] By using the winding end formed according to the present invention, a generator or an electric machine with a very large rotor diameter can also be formed outside of or on-site at the conventional manufacturing facilities, independent of the existing equipment capabilities regarding available forging and / or rolling.

Claims

1. A method for manufacturing a winding end support for supporting a rotor of a rotating electrical machine, wherein the winding end support includes one or more rings having an inner diameter exceeding 4 m and is formed using an additive manufacturing method, and the winding end support is formed by cladding a plurality of layers of metal, the winding end support is formed by arranging a plurality of layers so as to overlap each other in a direction intersecting the inner diameter, and the plurality of layers are connected by welding, in one of the plurality of layers, a plurality of weld seams are arranged in the direction of the inner diameter and are connected by welding, A layer is formed by first forming an inner boundary and an outer boundary of the layer, and then filling a material into a space between the inner boundary and the outer boundary. Method.

2. The method according to claim 1, wherein the additive manufacturing method is an arc wire cladding method.

3. The method according to claim 1 or 2, wherein the winding end support has a ring.

4. The method according to any one of claims 1 to 3, wherein an austenite structure is formed by the additive manufacturing method.

5. The method according to any one of claims 1 to 4, wherein the winding end support is formed by applying a material to a movable supporting element.

6. The method according to claim 5, wherein the supporting element rotates about a rotation axis about which the rotor rotates.

7. The method according to any one of claims 1 to 6, wherein the formation of the winding end support is performed using a protective gas in order to avoid an oxide layer in the winding end support.

8. The method according to any one of claims 1 to 7, wherein the winding end support is formed of steel having a chromium equivalent of 6% to 32%.

9. A method for manufacturing a winding end support for supporting a rotor of a rotating electrical machine, wherein the winding end support includes one or more rings having an inner diameter exceeding 4 m and is formed using an additive manufacturing method, and the winding end support is formed by cladding a plurality of layers of metal, the winding end support is formed of steel having a chromium equivalent of 6% to 32%, Method.

10. The method according to claim 8 or 9, wherein the winding end support is formed of steel having a chromium equivalent of 10% to 28%.

11. The method according to claim 10, wherein the winding end support is formed of steel having a chromium equivalent of 18% to 24%.

12. The method according to any one of claims 1 to 11, wherein the winding end support is formed of steel having a nickel equivalent of 10% to 40%.

13. A method for manufacturing a winding end support for supporting a rotor of a rotating electrical machine, wherein the winding end support includes one or more rings having an inner diameter exceeding 4 m, and is formed using an additive manufacturing method, and the winding end support is formed by cladding a plurality of layers of metal. The winding end support is formed of steel having a nickel equivalent of 10% to 40%. Method.

14. The method according to claim 12 or 13, wherein the winding end support is formed of steel having a nickel equivalent of 16% to 32%.

15. The method according to claim 14, wherein the winding end support is formed of steel having a nickel equivalent of 24% to 29%.

16. The method according to any one of claims 1 to 15, wherein the manufacturing is performed by cooling a previously formed portion of the winding end support.

17. The cooling is performed by applying a first fluid to a previously formed portion of the winding end support and / or a body thermally connected to the winding end support, and the first fluid has a temperature lower than that of the formed portion of the winding end support. The method according to claim 16.

18. The first fluid is air, CO ２ or water, the method according to claim 17.

19. The method according to any one of claims 16 to 18, wherein the winding end support is disposed on a platform during the manufacturing, and the platform is cooled by a second fluid.

20. The method according to claim 19, wherein the second fluid is water.

21. After the additive manufacturing method is executed, the formed portion of the winding end support is heat-treated, and the heat treatment includes solution annealing, quenching and / or stress relief annealing. The method according to any one of claims 1 to 20.

22. After the additive manufacturing method is executed, the formed portion of the winding end support is subjected to a machining manufacturing method. The method according to any one of claims 1 to 21.

23. A winding end support for a rotor of an electrical machine, wherein the winding end support is formed by the additive manufacturing method according to any one of claims 1 to 22, and includes one or more rings having an inner diameter exceeding 4 m. Winding end support.

24. The winding end support according to claim 23, wherein at least one of the rings has an inner diameter exceeding 6 m.

25. An electric machine comprising a stator and a rotor, wherein the rotor has at least one winding end portion on one end side, and a winding end portion support is provided for receiving centrifugal force generated during operation, and the winding end portion support according to claim 23 or 24 is embodied.

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