Method for producing a winding for an electrical machine

Abstract

The invention relates to a method for producing an insulated winding for an electrical machine, in particular an electric motor or generator, comprising the steps: i. Providing a winding, in particular according to the method according to claim 2, ii. Insulating winding sections from each other, and iii. insulating at least a portion of an outer surface of the winding, wherein the insulating according to iii. is carried out by a different method than the insulating under ii.

Description

[0001] The invention relates to an electrical machine, in particular an electric motor or generator, and a winding for such an electrical machine. Furthermore, the invention relates to a method and system for producing a winding for an electrical machine.

[0002] Processes for manufacturing windings for electrical machines are generally known. For example, the windings are produced by deforming a wire or by metal casting. Insulation of the winding can be achieved by coating it with varnish (so that the winding is insulated both from the outside and from individual, particularly adjacent, winding sections).

[0003] It is also known to produce windings for electrical machines using 3D printing. However, such 3D printing is still relatively expensive, especially for large quantities.

[0004] The object of the invention is to propose a method for producing a winding for an electrical machine, wherein the method results in comparatively precise components that are as efficient as possible in operation at comparatively low cost. Furthermore, the object of the invention is to propose a corresponding system, a corresponding winding, and a corresponding electrical machine.

[0005] The problem is solved in particular by the features of claim 1.

[0006] In particular, the object is achieved according to a first aspect by a method for producing an insulated winding for an electrical machine, in particular an electric motor or generator, comprising the steps: i) providing a (particularly concentrated) winding (particularly according to the method according to the third aspect explained in more detail below), ii) insulating winding sections from each other, and iii) insulating at least a portion of an outer surface of the winding, wherein the insulating according to iii) is carried out by a different method than the insulating under ii).

[0007] In the first aspect, the provision of the winding may comprise cutting, in particular laser cutting, and / or (subsequent) welding, in particular laser welding, of winding sections.

[0008] One idea according to the first aspect is that the insulation of an area between winding sections and the insulation of an outer surface of the winding are carried out using different methods. This allows insulation to be individually adapted to the actually necessary requirements. This is based in particular on the recognition that these requirements are and can be different. For insulation to the outside, comparatively pronounced insulation is necessary, especially for higher breakdown capacities. Between (adjacent) individual winding sections, on the other hand, comparatively less pronounced insulation may be acceptable, since the voltage differences are comparatively small.

[0009] If only one winding is mentioned, this means in particular the winding without insulation, unless otherwise stated, e.g. an “insulated winding”.

[0010] An outer surface of the winding is understood, in particular, to be a surface whose surface normal (at any point) either does not intersect the winding (again) or is directed toward the interior of the winding. For example, if the winding is configured as a hollow cylinder, both the outward-facing and the inward-facing surfaces of the hollow cylinder form an outer surface.

[0011] In particular, the isolation of functional sections from one another means that sections of the winding that are essentially adjacent to one another are separated by insulation. This particularly applies to sections that are not part of the outer surface or sections where a surface normal (to any point of the corresponding surface) intersects the winding once more (namely, in particular, at the adjacent winding section).

[0012] The above-mentioned object is achieved according to a second aspect (which is preferably combined with the first aspect) by a method for producing an insulated winding for an electrical machine, in particular an electric motor or generator, comprising the steps: - Providing a (particularly concentrated) winding (particularly according to the method according to the third aspect explained in more detail below), - Insulating at least one section of an outer surface of the winding, wherein an infiltrable surface material is applied and cast with a casting compound, in particular in a casting mold.

[0013] In the second aspect, step ii) and / or step iii) can be performed during the insulation process. Providing the winding can comprise cutting, in particular laser cutting, and / or (subsequent) welding, in particular laser welding, of winding sections.

[0014] One idea of ​​the second aspect is that an infiltrable (impregnable) surface material is considered and cast with an (insulating) potting compound. The infiltrable surface material (preferably in the form of a fleece) can serve as a spacer, particularly in a potting mold, so that a homogeneous distribution of the potting compound with a (at least essentially) constant layer thickness can be achieved. This allows for a clearly predefined connection of the winding material to form an insulated winding in a simple manner.

[0015] The above-mentioned object is achieved according to a third aspect (which is preferably combined with the first and / or second aspect) in particular by a method for producing a winding for an electrical machine, in particular an electric motor or generator, comprising: - providing winding sections by laser cutting, and - connecting the winding sections to form a (particularly concentrated) winding, in particular a single coil, by laser welding.

[0016] In the third aspect, step ii) and / or step iii) can be performed. Alternatively or additionally, in the third aspect, at least a portion of an outer surface of the winding can be insulated, wherein an infiltrable surface material is applied and encapsulated with a potting compound, in particular in a potting mold.

[0017] One idea behind the third aspect is to combine laser cutting with laser welding. This allows the geometric freedom provided by laser cutting to be utilized, while laser welding allows for a relatively precise winding.

[0018] A (respective) winding section can comprise (within the winding) at least half a turn and / or at most two turns, preferably exactly one turn. This preferably applies to at least 50%, preferably at least 90%, of the winding sections (in terms of number and / or length).

[0019] The respective process can be carried out in such a way that no free space (not covered by insulation) remains between adjacent winding sections.

[0020] The (respective) winding (coil) is preferably a single winding or single coil.

[0021] A method for insulating winding sections from one another and a method for insulating at least one section of the outer surface of the winding may differ from one another in that the insulation is applied in a different manner and / or different materials (insulating materials; for the insulation) are used and / or a different thickness (of an insulating layer) is set and / or the respective insulations are applied at different times (during the manufacturing process). For example, the respective insulation methods may differ in that fewer materials (possibly only one material) are used in the method according to ii) than in the method according to iii).

[0022] The method preferably comprises blocking the winding into a block, preferably by gluing. Alternatively or (preferably) additionally, the method comprises milling at least sections of an outer surface of the block (for the (final) definition of its shape). A combination of the laser cutting explained above, the laser welding, the blocking mentioned here, and the milling leads to an insulated winding with precise geometry and dimensional accuracy, in particular with high surface accuracy. Such surface accuracy is particularly advantageous when the (high-quality) insulation explained above or described further below is implemented.

[0023] Insulation (preferably of winding sections from one another, in particular the insulation according to ii) or step iii)) preferably comprises the introduction of an insulating film, in particular a preferably pre-impregnated insulating paper (prepreg). Such an insulating film (insulating paper, in particular for layer insulation) can first be inserted between two adjacent winding sections, wherein the winding sections or the entire winding are then pressed (for example using a disc spring), heated (for example to a temperature of at least 50 °C, preferably at least 80 °C, preferably at least 100 °C) and preferably subjected to a pressure of at least 2 Newton / mm 2 , preferably at least 4 Newton / mm 2The result of such layer insulation or pressing can be a block-like insulated winding (coil), in which, in particular, individual winding sections cannot be moved away from one another, but rather lie firmly against one another (structurally connected via a respective insulating film or a plurality of correspondingly inserted insulating films).

[0024] Insulating at least a portion of the outer surface of the winding, in particular the insulation according to ii) or in step iii) may alternatively or additionally comprise: - applying a plastic, preferably provided with a fabric and / or grid structure, in particular a polymer, preferably polyimide, and / or - applying an infiltrable surface material, in particular fleece (for example felt), in particular to the plastic and / or - applying a casting compound, in particular casting the fleece, preferably in a casting mold in which the winding with the fleece is arranged.

[0025] The plastic can be in the form of a liner, in particular a polymer liner, preferably a polyimide liner (or comprise such a liner), which is preferably provided with a grid structure (e.g., fabric). The plastic (liner, preferably a polyimide liner or PI liner) can be (previously) cut, in particular laser cut. The plastic (liner / PI liner) can be glued to / on the outer surface of the winding (coil). The plastic forms a first insulation that already has a high dielectric strength.

[0026] An infiltrable surface material, such as a fleece (felt), can be applied to the plastic (liner / PI liner, possibly with a grid structure or fabric). The infiltrable surface material, particularly the fleece (felt), preferably creates a defined distance from the walls of a (casting) mold or is relatively easy to cast (impregnate).

[0027] The lattice structure or fabric can preferably comprise a glass fiber fabric (or glass mesh fabric) and / or a carbon fiber fabric (or carbon mesh fabric). The lattice structure or fabric enables or simplifies the adhesion of the potting material, in particular resin (which in turn forms a reliable bond with the nonwoven fabric). In a synergistic manner, this ensures that the comparatively brittle potting material (resin) exhibits a good bond to the comparatively smooth plastic (liner / PI liner).

[0028] Polyimide is a (highly) efficient insulation material (approx. 6 kV breakdown voltage at a thickness of 0.030 mm) and preferably forms a first insulation system.

[0029] The impregnable surface material (fleece) preferably has a dual function, namely as a spacer and to absorb an infiltrate (resin in its initial liquid state).

[0030] The resin is, in particular, a (highly) efficient insulation material, which preferably forms a further insulation system. The resin also preferably has a geometric (shaping) function and / or a further function (connecting all other components). The layer thickness of the resin can be at least 0.010, preferably at least 0.100 and / or at most 2.0, preferably at most 0.300 mm. The infiltrable surface material, in particular the nonwoven (felt), can, for example, comprise or be formed from plastic, in particular polymer. The nonwoven preferably comprises PET (polyethylene terephthalate, for example, at least 50%, at least 80%, or at least 99%). The basis weight of the infiltrable surface material, in particular the nonwoven, can be at least 10 g / m 2 , preferably at least 30 g / m 2 and / or a maximum of 100 g / m 2 , preferably not more than 50 g / m 2be.

[0031] A material used for potting (especially in the potting mold) can be epoxy-based. For example, a two-component epoxy system can be used. Potting can be performed in a vacuum.

[0032] The (solidified) potting compound (with the infiltrable or infiltrated surface material) represents a second insulation which, particularly in combination with the first insulation, provides an advantageous, precise and yet comparatively easy-to-manufacture (total) insulation for the outside of the winding.

[0033] A thickness of a (total) insulation on an outer surface of the winding is preferably at least 1.2 times, more preferably at least 2.0 times and / or at most 20 times, optionally at most 10 times or at most 5 times as large as a thickness of an insulation between (the) winding sections of the winding.

[0034] The thickness of the (total) insulation on an outer surface of the winding can be, for example, at least 0.30 mm or at least 0.60 mm and / or at most 3 mm, optionally at most 1.5 mm. The thickness mentioned in the preceding sentence can be in mm at least 0.015, preferably at least 0.050, optionally at least 0.100 and / or at most 2.5, preferably at most 0.300, optionally at most 0.200. The thickness of the insulation between the winding sections of the winding can be, for example, at least 0.01 mm or at least 0.05 mm or at least 0.01 mm and / or at most 0.5 mm. The thickness mentioned in the preceding sentence may be at least 0.005, preferably at least 0.020, possibly at least 0.030 and / or at most 0.5, preferably at most 0.100, possibly at most 0.070, in mm.

[0035] The (respective) thickness can be constant or vary. If the (respective) thickness varies, an average thickness should be used, taking into account the above information on specific (relative or absolute) values, which represents the largest proportion of the total area of ​​the respective layer in relation to the total area. Alternatively or additionally, an average thickness can be used (determined by dividing the respective layer under consideration into square cells with an edge length of 1 mm and calculating the arithmetic mean).

[0036] The (respective) winding section is preferably a section of the winding that rotates (exactly) once (and then ultimately transitions into the next winding section, whereby an interface can be connected in particular by laser welding).

[0037] The (individual or respective) winding section preferably has a constant thickness (like a sheet). The (respective) winding section can have a rectangular configuration, wherein one side of the rectangle is, for example, at least 1.5 times, at least 3 times, and / or at most 10 times as large as another side of the rectangle. A thickness of the individual (respective) winding section can, for example, be at least 0.2 mm, at least 1 mm, at least 2 mm, and / or at most 5 mm.

[0038] The winding may comprise at least three winding sections, possibly at least eight winding sections and / or a maximum of 100 winding sections, possibly a maximum of 50 winding sections.

[0039] A material for the (conductive) part of the winding is preferably copper or a copper alloy, or aluminum or an aluminum alloy.

[0040] The above-mentioned object is further achieved in particular by a system, in particular for carrying out the above method, for producing an insulated winding for an electrical machine, in particular an electric motor or generator, comprising: - a provision device for providing a winding, in particular according to the above method, - a first insulation device for isolating winding sections from one another, and - a second insulation device for insulating at least a portion of an outer surface of the winding.

[0041] The above-mentioned object is further achieved in particular by a system, in particular according to the immediately preceding paragraph and / or for carrying out the above method, for producing an insulated winding for an electrical machine, in particular an electric motor or generator, comprising: - a provision device for providing a winding, - an insulation device for insulating at least a portion of an outer surface of the winding in such a way that an infiltrable surface material is applied and cast with a casting compound, in particular in a casting mold.

[0042] The above-mentioned object is further achieved in particular by a system, in particular according to one of the two immediately preceding paragraphs and / or for carrying out the above method, for producing a winding for an electrical machine, in particular an electric motor or generator, comprising: - a laser cutting device for providing winding sections by laser cutting, and - a laser welding device for connecting the winding sections to form a winding, in particular a single coil, by laser welding.

[0043] The system (according to one or both of the previous paragraphs) shall preferably further comprise: - a blocking device for blocking the winding into a block by gluing, and / or - a milling device for milling at least sections of an outer surface of the block (for the (final) definition of its shape).

[0044] The above-mentioned object is further achieved in particular by a winding for an electrical machine, in particular an electric motor or generator, produced according to the above method and / or the above system.

[0045] The above-mentioned object is further achieved in particular by an electrical machine, in particular an electric motor or generator, comprising the above winding.

[0046] Preferably, the insulation according to iii) is carried out after the insulation according to ii).

[0047] Further embodiments emerge from the subclaims.

[0048] The invention is described below using exemplary embodiments, which are explained in more detail with reference to the figures. Herein: Fig. 1 is an oblique view of a winding according to the invention; Fig. 2 shows a schematic cross-section of a winding according to the invention; Fig. 3 a schematic cross-section of a comparative example; Fig. 4 a schematic winding in a view from above; Fig. 5 the winding according to Fig. 4 after an isolation process step; Fig. 6 the winding according to Fig. 4 after a further process step for isolation; Fig. 7 a casting mould for the insulation of the winding according to Fig. 4; and Fig. 8 the winding according to Fig. 6 in the casting mould according to Fig. 7.

[0049] In the following description, the same reference numbers are used for identical and equivalent parts.

[0050] Fig. Figure 1 shows a winding 10 according to the invention in a schematic oblique view. This winding comprises a plurality of winding sections 11, each of which has a rectangular configuration, so that the winding also has an (at least substantially) rectangular configuration in a plan view in the axial direction. The individual winding sections 11 can be cut from a sheet by laser cutting and joined to one another by laser welding to form the Fig. 1. Laser welded connections are schematically symbolized by lines 20.

[0051] Alternatively or additionally, the winding 10 can also be produced by casting (investment casting) or 3D printing (in particular laser sintering and / or laser melting).

[0052] In Fig. Figure 2 shows a highly schematic cross-section through the winding.

[0053] The winding is provided with an outer insulation 12 and intermediate insulations 13. The intermediate insulations 13 are (considerably) thinner than the outer insulation 12. In comparison, in Fig. 3 (also highly schematic) shows a corresponding cross-section of a coil manufactured using a conventional process. Here, the (winding) conductor is completely covered with insulation, so that in the area between the winding sections 11, a comparatively thick (and unnecessarily complex) insulation is present (which can basically be twice as thick as the insulation on outer sections; corresponding to the outer insulation 12 in Fig. 2).

[0054] In the inventive solution according to Fig. 2 takes advantage of the fact that there is a comparatively low voltage between the layers (or the winding sections 11), so that there is a correspondingly lower insulation requirement.

[0055] This allows a fill factor (copper fill factor) to be increased (e.g. by 3% for 24 turns).

[0056] In contrast to the conventionally manufactured winding according to Fig. 3, a comparatively thin and simple insulation layer is present between the winding sections (instead of a double-sided coating). In particular, by inserting individual intermediate insulation layers 13 (e.g., as prepreg), no curvatures (radii) are necessary in the respective edge areas, which further reduces shaping restrictions. Bending radii that may be required during production (if bending is required to apply the insulation) are also eliminated when using the procedure according to Fig. 2 is unproblematic, as this procedure does not require bending.

[0057] The result is a different insulation with respect to the intermediate insulation 13 and the outer insulation 12, which allows a simple yet effective space-saving winding production.

[0058] The Fig. 2 recognizable intermediate insulations 13 can be produced by first placing them between the winding sections 11, then at a temperature of at least 100 °C and a pressure of at least 2 Newton / mm 2 be pressed (for example using a disc spring).

[0059] Preferably after the intermediate insulation 13 and before the outer insulation according to Fig. 2, the winding can be milled to adjust or define its (final) shape. This improved, simple adjustment with high precision can synergistically facilitate the provision of the outer insulation 12 explained below, since a comparatively flat surface is particularly advantageous for this purpose.

[0060] As an alternative to milling, increased accuracy could also be achieved by using a particularly precise pressing device.

[0061] Fig. 4 shows again the winding 10 according to Fig. 1 in a highly schematic plan view (still without insulation).

[0062] In Fig. 5 the winding is according to Fig. 4, where the increased line thickness indicates a polyimide liner that is covered with a fabric. The PI liner can be laser cut and bonded to the winding.

[0063] In the following step, a felt can be applied to the polyimide and the fabric, which Fig. 6 is represented by the further increased line thickness and schematically indicated fibers 18.

[0064] To complete the insulation, you can now proceed according to Fig. 7 a casting mold 14 (for example with a first mold part 15 and a second mold part 16 and a core 19) is provided, wherein the casting mold is optionally openable and closable and in the closed state defines a cavity 17, which here, for example, approximately corresponds (at least schematically viewed) to a Q. The winding (or coil) can now be inserted into the casting mold 14 according to Fig. 6 (including PI liner, with fabric and felt or fleece) are inserted (see Fig. 8), whereby the fleece easily creates a (precise) distance from the mold. Furthermore, the fleece (felt) is comparatively easy to cast or impregnate. As a result, a process is proposed in which precise insulation can be achieved in a simple manner.

[0065] The fleece can be based on PET or made from it.

[0066] The actual casting can be carried out as vacuum casting.

[0067] A 2-component epoxy system can be used as a casting compound.

[0068] After curing the winding according to Fig. 8 this is insulated, so that an insulated winding is present.

[0069] At this point, it should be noted that all parts described above, viewed individually and in any combination, particularly the details shown in the drawings, are claimed as essential to the invention. Modifications to these are familiar to those skilled in the art.

[0070] It should also be noted that the aim is to achieve the broadest possible scope of protection. In this respect, the disclosure contained in the claims can also be made more precise by features that are described with further features (even without these further features necessarily being included). It is explicitly pointed out that parentheses and the term "in particular" are intended to emphasize the optionality of features in the respective context (which does not mean, conversely, that without such identification a feature is to be regarded as mandatory in the corresponding context). The term "element / elements" should preferably characterize a coherent structure, which in turn can be connected to at least one other structure (to form a possibly one-piece and / or inherently immobile overall structure) or can be delimited from all other structures. Reference symbol 10 windings 11 Winding section 12 External insulation 13 Intermediate insulation 14 Casting mold 15 first molded part 16 second molded part 17 Cavity 18 fibers 19 core 20 laser welding connections

Claims

[1] Method for producing an insulated winding (10) for an electrical machine, in particular an electric motor or generator, comprising the steps: i. Providing a winding (10), in particular according to the method according to claim 3, ii. Insulating winding sections (11) from each other, and iii. insulating at least a portion of an outer surface of the winding (10), wherein the insulating according to iii. is carried out by a different method than the insulating under ii. [2] Method, in particular according to claim 1, for producing an insulated winding (10) for an electrical machine, in particular an electric motor or generator, comprising the steps: - Providing a winding (10), in particular according to the method according to claim 3, - Insulating at least one section of an outer surface of the winding (10), wherein an infiltrable surface material is applied and cast with a casting compound, in particular in a casting mold. [3] Method, in particular according to claim 1 or 2, for producing a winding (10) for an electrical machine, in particular an electric motor or generator, comprising: - providing winding sections (11) by laser cutting, and - connecting the winding sections (11) to form a winding (10), in particular a single coil, by laser welding. [4] Method according to one of the preceding claims, wherein a / the method for insulating winding sections (11) from one another and a / the method for insulating at least one section of an outer surface of the winding (10) differ from one another in that the insulation is applied in a different way and / or different materials are used and / or a different thickness is set and / or the respective insulations are applied at different times. [5] Method according to one of the preceding claims, comprising: - blocking the winding (10) into a block by gluing, and / or - milling of at least sections of an outer surface of the block. [6] Method according to one of the preceding claims, wherein an insulation, preferably of winding sections (11) from one another, in particular the insulation in step ii), comprises: introducing an insulating film, in particular a preferably pre-impregnated insulating paper. [7] Method according to one of the preceding claims, wherein insulating, preferably insulating at least a portion of an outer surface of the winding (10), in particular insulating in step iii), comprises: Applying a plastic, preferably provided with a fabric and / or grid structure, in particular a polymer, preferably polyimide, and / or Applying an infiltrable surface material, in particular a fleece, in particular to the plastic and / or Applying a casting compound, in particular casting the infiltrable surface material, preferably in a casting mold (14) in which the winding (10) with the infiltrable surface material is arranged. [8] Method according to one of the preceding claims, wherein a thickness of an insulation on / the outer surface of the winding (10) is at least 1.2 times, preferably at least 2.0 times and / or at most 20 times as large as a thickness of an insulation between (the) winding sections (11) of the winding (10). [9] System, in particular for carrying out the method according to one of the preceding claims, for producing an insulated winding (10) for an electrical machine, in particular an electric motor or generator, comprising: - a provision device for providing a winding (10), in particular according to the method according to claim 3, - a first insulation device for insulating winding sections (11) from one another, and - a second insulation device for insulating at least a portion of an outer surface of the winding (10). [10] System, in particular according to the immediately preceding claim and / or for carrying out the method according to one of the preceding claims, for producing an insulated winding (10) for an electrical machine, in particular an electric motor or generator, comprising: - a provision device for providing a winding (10), in particular according to the method according to claim 3, - an insulation device for insulating at least a portion of an outer surface of the winding (10) in such a way that an infiltrable surface material is applied and cast with a casting compound, in particular in a casting mold. [11] System, in particular according to one of the two immediately preceding claims and / or for carrying out the method according to one of the claims preceding the immediately preceding claim, for producing a winding (10) for an electrical machine, in particular an electric motor or generator, comprising: - a laser cutting device for providing winding sections (11) by laser cutting, and - a laser welding device for connecting the winding sections (11) to a winding (10), in particular a single coil, by laser welding, and preferably further comprising: - a blocking device for blocking the winding (10) into a block by gluing, and / or - a milling device for milling at least sections of an outer surface of the block (for the (final) definition of its shape). [12] Winding (10) for an electrical machine, in particular an electric motor or generator, manufactured according to the method or the system according to one of the preceding claims, or electrical machine, in particular an electric motor or generator, comprising such a winding (10).

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