Method for producing a material layer package for an electric machine

Abstract

The invention relates to a method for producing a material layer package (2) for an electric machine (22). To improve the method, the following steps are proposed: producing (A) material layers (8) from a green body by means of a sintering method, in particular a pressureless sintering method, wherein the material layers (8) each have a first thickness (d1) in the range from 0.5 µm to 500 µm, in particular 10 µm to 300 µm; applying (B) an adhesive coating to the sintered material layers (8); bonding (C) a plurality of material layers (8) to form a material layer stack (12); stacking (E) a plurality of material layer stacks (12); and connecting (F) the material layer stacks (12) to form a material layer package (2).

Description

[0001] Description

[0002] Method for producing a material layer package for an electrical machine

[0003] The invention relates to a method for producing a material layer package for an electrical machine.

[0004] Furthermore, the invention relates to a material layer package for an electrical machine.

[0005] Furthermore, the invention relates to an electrical machine with at least one such material layer package.

[0006] In rotating electrical machines, such as motors and generators, laminated cores made of stacked electrical sheets are typically used to suppress the propagation of eddy currents. Transformers and switching devices are examples of other electrical machines that may have such laminated cores.

[0007] The electrical sheets of the laminated cores, which contain, for example, a soft magnetic material, particularly iron, are usually cut or punched from rolled large sheets. The sheets are then packaged into a laminated core. Using such a conventional manufacturing process, it is currently not possible to produce sheets with a layer thickness of less than 100 μm on an industrial scale. Furthermore, waste is generated when the sheets are cut or punched from the large sheets.

[0008] The patent document DE 10 2007 024 822 B3 describes a method for assembling a stator for an electrical machine.

[0009] The sheets can be joined to form a laminated core in various ways. The published patent application EP 3 353 241 A1 describes a thermally activatable adhesive composition for use in a method for producing a laminated core from bonded sheet metal components.

[0010] The published patent application EP 0 121 173 A2 describes a method for producing a package of layered laminations for electrical machines and devices, in which the laminations, after punching out and arranged at a mutual distance from one another, are exposed to a reducing gas atmosphere in an annealing treatment and then joined together to form the final lamination package shape, wherein, in order to mutually connect the laminations to be joined together to form a lamination package, corresponding elevations and depressions known in the punching and packaging process are punched or embossed into them and the laminations of a lamination package are joined together by means of the interlocking elevations and depressions by axial pre-pressing before annealing to form a structure with guaranteed minimum axial mutual distance and after the annealing treatment by axial final pressing to form the final lamination package shape.

[0011] Material layers with very low layer thicknesses lead to a significant reduction in eddy current losses.

[0012] The published patent application EP 3 595 148 A1 describes a method for producing a material layer with a layer thickness of between 0.5 and 500 pm, comprising the steps of: applying a suspension comprising at least one binder and solid particles through a stencil onto a base surface to obtain a green body, expelling the binder from the green body, in particular by debinding, creating a permanent cohesion of the solid particles by heating and / or by compaction, in particular by sintering.

[0013] Such thin material layers tend to bulge, which causes problems, especially when shrink-fitting or pressing a material layer package into a housing. Furthermore, at least some of the thin material layers require individual rework, which leads to high costs.

[0014] The invention is therefore based on the object of improving the production of material layer packages for electrical machines.

[0015] This object is achieved according to the invention by a method for producing a material layer package for an electrical machine, comprising the following steps: producing material layers from a green body by means of a sintering process, in particular a pressure-free sintering process, the material layers each having a first thickness in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm, applying an adhesive coating to the sintered material layers, bonding a plurality of material layers to form a material layer stack, stacking a plurality of material layer stacks, connecting the material layer stacks to form a material layer package.

[0016] Furthermore, the object is achieved according to the invention by a material layer package for an electrical machine, which comprises a plurality of material layer stacks connected to one another, wherein the material layer stacks each have a plurality of material layers which are glued to one another by means of an adhesive coating, wherein the material layers are produced from a green body by means of a, in particular pressureless, sintering process, and each have a first thickness in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm.

[0017] Furthermore, the object is achieved according to the invention by an electrical machine with at least one such material layer package.

[0018] The advantages and preferred embodiments listed below with regard to the method can be transferred analogously to the material layer package and the electrical machine.

[0019] The invention is based on the idea of ​​improving a method for producing material layer packages for electrical machines, which is constructed from thin material layers sintered from a green body, in particular without pressure, by improving the rigidity of the material layers to be packaged while maintaining the same eddy current suppression. This is achieved by combining a plurality of material layers, each having a first thickness in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm, to form a material layer stack. The individual material layers of the material layer stack are connected to one another via an adhesive coating. For example, the adhesive coating can be electrically insulating, with such an adhesive coating providing electrical insulation between the material layers in addition to corrosion protection.In particular, the material layer stack can have a thickness in the range of 200 μm to 1 mm, which is in the range of an electrical sheet produced by rolling. The increased rigidity significantly simplifies handling for joining the material layer stacks into a material layer package. In addition to increasing throughput, this results in a significant reduction in costs, which is attributable, among other things, to the reduced number of individual parts in the process flow.

[0020] A further embodiment provides that, prior to joining, the contour of the material layer stack is adjusted to a desired contour. The contour comprises, for example, a, particularly outer, surface of the material layer stack. Adjusting the contour of the material layer stack to a desired contour is also called a calibration process. By increasing the rigidity by bonding the material layers to form a material layer stack, the calibration process is simplified, and known manufacturing processes for electrical steel sheets produced by rolling can be applied.

[0021] Another embodiment provides for the alignment to be performed by punching, eroding, and / or cutting, particularly laser cutting. Such processes are cost-effective and easy to apply.

[0022] A further embodiment provides that the green body for producing the material layers is produced from a suspension which comprises at least solid alloy particles and at least one binder. The solid alloy particles can contain iron, in particular pure iron, and / or cobalt. The binder, which acts as a liquid adhesive, can be, for example, an organic binder which is removed before sintering or during the sintering process. In particular, the suspension is in the form of a paste. The green body for obtaining the thin material layers can be produced using an additive process, among other things. Additive processes for producing the green body can include screen printing, stencil printing, and roller printing. Thin material layers can be produced easily and inexpensively using suspensions of this type.

[0023] Another embodiment provides for the material layer stacks to be joined by force-fitting. The increased rigidity of the laminates compared to thin individual sheets eliminates the need for complete bonding of all individual sheets, which saves costs and time and simplifies subsequent processes.

[0024] Another embodiment provides for the force-locking connection to be achieved by means of punching and stacking. For example, a stack of material layers is pressed plastically at one or more points into an opening in a material layer stack located below it using a tool, creating a force-locking connection between the individual material layer stacks. In particular, the joining process of star and yoke stacks is simplified because known manufacturing processes, such as the star-yoke stack technology, can be used.

[0025] A further embodiment provides for an adhesive varnish, in particular a self-bonding varnish, to be applied during the application of the adhesive coating. For example, material layers are bonded together to form stacks of material layers by pressing them together under pressure and heat. In particular, the use of self-bonding varnish achieves high electrical insulation between the material layers. Furthermore, corrosion is prevented by the bonding of the material layers, and improved mechanical strength and rigidity are achieved.

[0026] A further embodiment provides for the material layer stacks to be bonded together, particularly additionally, adhesively. This is advantageous because it results in improved mechanical strength and rigidity.

[0027] It shows :

[0028] FIG 1 is a schematic representation of a method for producing a material layer package,

[0029] FIG 2 a schematic representation of a material layer package,

[0030] FIG 3 a three-dimensional representation of a material layer package for an electrical machine and

[0031] FIG 4 is a schematic longitudinal section of an electrical rotating machine.

[0032] The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual features of the invention that are to be considered independently of one another. These features also further develop the invention independently of one another and are thus to be considered as part of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0033] The same reference symbols have the same meaning in the different figures.

[0034] FIG. 1 shows a schematic representation of a method for producing a material layer stack 2 comprising a centrally arranged recess 4 through which an axis 6 is arranged. In particular, the material layer stack 2 is designed to be substantially rotationally symmetrical to the axis 6. The material layer stack 2 can be configured for a stator or a rotor of an electrical rotating machine.

[0035] The manufacturing method comprises producing A material layers 8 from a green body by means of a sintering process, in particular a pressure-free sintering process, wherein the material layers 8 are essentially flat and arranged in an xy plane. The material layers 8 each have a first thickness dl in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm. In particular, the material layers 8 have an essentially identical first thickness dl. Such a green body for obtaining the material layers 8 is produced from a suspension which comprises solid alloy particles and at least one binder, by means of an additive process. Additive processes for producing the green body can include screen printing, stencil printing and roller printing. The binder, which acts as a liquid adhesive, can be, for example, an organic binder which is removed before sintering or during the sintering process.In particular, the suspension is in the form of a paste. Solid alloy particles containing iron, in particular pure iron, and / or cobalt are used for the green body of the first material layers 8. In addition, the suspension can contain, among other things, sintering aids, in particular powdered ones. For example, the sintering aids in the sintered first material layers 8 have a weight fraction in the range from 0.4% to 1%. For example, when producing an iron-cobalt alloy, the sintering aids contain phosphorus compounds, e.g. iron phosphides, and / or boron compounds, e.g. iron borides. The sintering aids form eutectics with the alloys to be sintered, whereby blowholes and pores are largely avoided, so that a high density is achieved in the pressureless sintering process.

[0036] The method further comprises applying B an adhesive coating 10 to the sintered material layers 8. The adhesive coating 10 may contain, among other things, an adhesive varnish, in particular a baking varnish, which is applied to one or both sides of the sintered material layers 8. The adhesive varnish is dried and activated, in particular thermally, in a subsequent process for bonding several material layers 8.

[0037] The method further comprises bonding C, for example, five coated material layers 8 to form a material layer stack 12 each. The adhesive coating 10 creates corrosion protection and electrical insulation between the material layers 8. A material layer stack 12 has, for example, a second thickness d2 in the range from 200 μm to 1 mm. Furthermore, an adjustment D of a contour 14 of the material layer stack 12 to a target contour takes place, which is also called a calibration process. The calibration process for producing the target contour takes place, for example, by means of punching. Additionally or alternatively, the calibration process includes erosion and / or cutting, in particular laser cutting. In a further step, a stacking E of a plurality of bonded and calibrated material layer stacks 12 takes place. In particular, the material layer stacks 12 of the material layer package 2 have a substantially identical first thickness d2.In addition, a connection F of the material layer stacks 12 to form a material layer package 2 takes place, wherein the connection F of the material layer stacks 12 takes place in a force-locking manner. The force-locking connection takes place by means of punching and stacking. In this case, for example, a material layer stack 12 is pressed with a tool 16 by means of a force Fz in the z-direction at one or more points into an opening in an underlying material layer stack 12, whereby a force-locking connection is created between the individual material layer stacks 12. The openings are not shown in FIG 1 for reasons of clarity. The connection F can additionally or alternatively include riveting, welding, in particular resistance or laser welding, thread pressing or cutting and / or adhesive connection of the material layer stacks 12.

[0038] FIG 2 shows a schematic representation of a material layer package 2 which is produced according to the method described in FIG 1. The material layer package 2 comprises a plurality of material layer stacks 12, wherein the material layer stacks 12 each have a plurality of material layers 8 which are glued to one another by means of an adhesive coating 10, wherein the adhesive coating 10 comprises an adhesive varnish, in particular a baking varnish. The material layer stacks 12 are non-positively connected to one another by means of punching and stacking. The further embodiment of the material layer package 2 in FIG 2 corresponds to that in FIG 1.

[0039] FIG 3 shows a three-dimensional representation of a material layer package 2 for an electrical rotating machine, which is designed as a star package and is manufactured according to the method described in FIG 1. The star package has a plurality of teeth 18, in each of which, for example, a punched package connection 20 is arranged for the non-positive connection of the material layer stacks 12. The star package, together with a yoke package, which is not shown in FIG 3 for reasons of clarity, can form a stator package for an electrical rotating machine. The yoke package can also be manufactured according to the method described in FIG 1. The further design of the material layer package 2 in FIG 2 corresponds to that in FIG 1.

[0040] FIG 4 shows a schematic longitudinal sectional view of an electrical rotating machine 22, which is designed as a synchronous machine, for example. The synchronous machine has a rotor 24 rotatable about an axis 8 and a stator 26 surrounding the rotor 24. Between the rotor 24 and the stator 26 there is a gap 28, which is designed in particular as an air gap. The rotor 24 comprises a shaft 30, which is mounted via bearings 32. The rotor 24 and the stator 26 are accommodated, for example, in a housing 34.

[0041] The rotor 24 and the stator 26 each have at least one material layer package 2, which is manufactured according to the method described in FIG. 1. In particular, the stator 26 has a star package 36 and a yoke package 38, as described in FIG. 4.

[0042] In summary, the invention relates to a method for producing a material layer package 2 for an electrical machine 22. In order to improve the method, the following steps are proposed: producing A material layers 8 from a green body by means of a sintering process, in particular a pressure-free sintering process, wherein the material layers 8 each have a first thickness d1 in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm, applying B an adhesive coating to the sintered material layers 8, bonding C a plurality of material layers 8 to form a material layer stack 12, stacking E a plurality of material layer stacks 12 and connecting F the material layer stacks 12 to form a material layer package 2.

Claims

Patent claims 1. A method for producing a material layer package (2) for an electrical machine (22) comprising the following steps: Producing (A) material layers (8) from a green body by means of a sintering process, in particular a pressureless sintering process, wherein the material layers (8) each have a first thickness (dl) in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm, applying (B) an adhesive coating to the sintered material layers (8), Gluing (C) a plurality of material layers (8) to form a material layer stack (12), stacking (E) a plurality of material layer stacks (12), connecting (F) the material layer stacks (12) to form a material layer package (2).

2. Method according to claim 1, wherein before the joining (F) an adjustment (D) of a contour (14) of the material layer stack (12) to a desired contour takes place.

3. Method according to claim 2, wherein the adjustment (D) is carried out by means of punching, eroding and / or cutting, in particular laser cutting.

4. Method according to one of the preceding claims, wherein the green body for producing the material layers (8) is produced from a suspension which comprises at least solid alloy particles and at least one binder.

5. Method according to one of the preceding claims, wherein the connection (F) of the material layer stacks (12) is effected by force-locking.

6. The method according to claim 5, wherein the force-fitting connection (F) is carried out by means of punching and packaging.

7. Method according to one of the preceding claims, wherein an adhesive varnish, in particular a baking varnish, is applied during the application (B) of the adhesive coating (10).

8. Method according to one of the preceding claims, wherein the application (B) is carried out on one or both sides.

9. Method according to one of the preceding claims, wherein the material layer stacks (12) are, in particular additionally, adhesively bonded to one another.

10. Material layer package (2) for an electrical machine (22), which comprises a plurality of interconnected material layer stacks (12), wherein the material layer stacks (12) each have a plurality of material layers (8) which are glued to one another by means of an adhesive coating (10), wherein the material layers (8) are produced from a green body by means of a sintering process, in particular a pressureless sintering process, and each have a first thickness (dl) in the range from 0.5 pm to 500 pm, in particular 10 pm to 300 pm.

11. Material layer package (2) according to claim 10, wherein the material layer stacks (12) are connected to one another in a force-fitting manner.

12. Material layer package (2) according to claim 11, The force-fitting connection is made by means of punching and packaging.

13. Material layer package (2) according to one of claims 10 to 12, wherein the adhesive coating comprises an adhesive varnish, in particular a baking varnish.

14. Material layer package (2) according to one of claims 10 to 13, wherein a material layer stack 12 has a second thickness d2 in the range from 200 pm to 1 mm.

15. Electrical machine (22) comprising at least one material layer package (2) according to one of claims 10 to 14.

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