METHOD FOR PRODUCING AN ELECTROMAGNETIC COMPONENT, IN PARTICULAR A LAMINATED CORE, FOR EXAMPLE A STATOR CORE OR A ROTOR CORE, FOR AN ELECTRIC MACHINE

Abstract

The invention relates to a method for producing an electromagnetic component. In particular, the electromagnetic component to be produced can be a laminated core, for example a stator core or a rotor core, and can be provided for use with an electric machine such as an electric motor.

The method has the following steps: A) providing a metal sheet as a starting material; B) punching out a number of lamellae from the metal sheet; C) heat-treating the lamellae; D) joining the heat-treated lamellae to form the component or a portion of the component.

The invention also relates to an electric machine.

Claims

1. A method for producing an electromagnetic component including at least of a laminated core, a stator core or a rotor core, for an electric machine, the method comprising: providing a metal sheet as a starting material, punching out a number of lamellae from the metal sheet, heat-treating the number of lamellae to provide heat-treated lamellae, and joining the heat-treated lamellae to form the electromagnetic component or a portion of the electromagnetic component.

2. The method according to claim 1, wherein the joining of the heat-treated lamellae comprises, sequentially for each of the heat-treated lamellae, the following steps: applying a thermally activated adhesive to a surface of the heat-treated lamella, substantially over the whole surface, to form an adhesive coating, and activating the adhesive of the adhesive coating, wherein the heat-treated lamellae having the activated adhesive are superimposed in a position-aligned and angularly aligned manner and are subjected, on their end face, to a compressive force acting in an axial direction.

3. The method according to claim 2, wherein the activating the adhesive includes illuminating the adhesive coating with infrared radiation using a means for emitting infrared radiation.

4. The method according to claim 3, wherein the illuminating the adhesive coating is carried out in an NIR wavelength range.

5. The method according to claim 3, wherein the means for emitting infrared radiation are, in terms of the processing sequence, arranged between a punching tool and an ejection punch, and includes: at least one upper lamp which is directed in a punching direction onto a first lamella surface or at least one lower lamp which is directed against a punching direction onto a second lamella surface present on the other side of the punching tool, or both at least one upper and at least one lower lamp.

6. The method according to claim 1, wherein the joining of the heat-treated lamellae comprises, sequentially for each of the heat-treated lamellae of the number of lamellae, the following steps: applying a thermally activated adhesive to a surface of the lamella, substantially over the whole surface, to form an adhesive coating, superimposing the heat-treated lamellae in a position-aligned and angularly aligned manner, applying a compressive force acting in an axial direction to the end face of the superimposed lamellae, and heating the superimposed lamellae, which are at least temporarily subjected to the compressive force, for a predetermined period of time at a predetermined temperature to activate the adhesive of the adhesive coating.

7. The method according to claim 6, wherein the predetermined period of time is between 5 minutes and 60 minutes.

8. The method according to claim 6, wherein the predetermined temperature is between 100° C. and 250° C.

9. The method according to claim 6, further comprising inspecting the adhesive coating using an optical inspection method and a respective heat-treated lamella is only used in the joining process if the optical inspection method detects a sufficiently uniform thickness distribution of the adhesive coating, and otherwise the respective heat-treated lamella is removed from the method as a reject.

10. The method according to claim 6, further comprising inspecting the adhesive coating using an optical inspection method, wherein the optical inspection method is the capture of a thermal image of the adhesive coating, which is not-yet-dry, by means of a thermal imaging camera.

11. The method according to claim 1, wherein the metal sheet is a panel made from an electrical steel strip or is an electrical steel strip or is a panel or a strip made of a soft magnetic material.

12. The method according to claim 1, wherein the metal sheet consists of a non-grain-oriented electrical steel strip.

13. The method according to claim 11, wherein the metal sheet, in addition to Fe and unavoidable impurities, consists of in wt. %: 0.1 to 3.50 Si, 0.01 to 1.60 Al, 0.07 to 0.65 Mn, and up to 0.25 P, wherein the sum of all components including unavoidable impurities is 100 wt. %.

14. The method according to claim 12, wherein the heat treatment is carried out as stress relief annealing.

15. The method according to claim 1, wherein a thermally activated adhesive is applied on both surfaces of the lamella.

16. The method according to claim 15, wherein the thermally activated adhesive contains: 60 parts by weight of an epoxy resin, 0.5 to 15 parts by weight of a latent hardener, 1 to 15 parts by weight of a latent accelerator.

17. An electric machine, having a first electromagnetic component and a second electromagnetic component, wherein the first electromagnetic component is produced using the method according to claim 1 and wherein the second electromagnetic component is joined as a laminated core consisting of lamellae, wherein the lamellae of the second electromagnetic component are not subjected to any heat treatment after being punched out of another metal sheet provided as a starting material, the first electromagnetic component being a stator and the second electromagnetic component being a rotor of the electric machine.

18. An electrical component or laminated core, produced using the method according to claim 1.

19. An electric machine having electrical components according to claim 18.

20. An electric machine according to claim 19, configured as an electric motor for a passenger car, a truck, a motorized two-wheeler, a small electric vehicle, an aircraft or a drone.

Description

[0147] It goes without saying that the features mentioned above and below can be used not only in the combination indicated but also in other combinations or in isolation.

[0148] In the drawings:

[0149] FIG. 1 schematically shows a first development of the invention as an embodiment,

[0150] FIG. 2 schematically shows an alternative development of the invention as an embodiment.

[0151] FIG. 1 schematically shows that a metal sheet 1 designed as a non-grain-oriented electrical steel strip is provided as a starting material. A number of lamellae 2 are punched out of the metal sheet with a punching tool 4 and are collected in a stack 3 in the embodiment shown. After punching, the lamellae are heat-treated in a furnace 5. The exact method of heat treatment is at the discretion of a person skilled in the art and depends in particular on the starting material; if grain growth is no longer desired, the heat treatment can in particular be stress relief annealing known to a person skilled in the art, i.e. slow heating in a temperature range below Ac1, holding in this temperature range for a long time, for example for 60 minutes, and slowly cooling down from room temperature. By carrying out a heat treatment, lamellae are obtained in which residual stresses that are still present due to the punching out, in particular in the edge regions, are removed or at least largely removed. With the lamellae obtained in this way, the joining of the heat-treated lamellae to form the laminated core or a portion of the laminated core can begin. For the joining of the lamellae, each of the lamellae of the number of lamellae is sequentially conveyed to different processing stations by a conveyor belt. In a first work station 6, an adhesive in the form of an aqueous dispersion is applied over the entire surface by means of a spray device 6′. The lamellae then have a thermally activated adhesive coating. Immediately after coating, a test station 7 uses a thermal imaging camera 7′ and a connected evaluation device to check that the applied coating is sufficiently free of defects and, if necessary, rejects are discarded. A drying station can optionally also be provided in order to dry the adhesive coating.

[0152] The lamellae provided with a sufficiently defect-free coating are then irradiated at an activation station under an NIR illumination device 8′ with NIR radiation, preferably with an emission power between 5 kW and 20 kW, to activate the adhesive of the adhesive coating.

After the adhesive has been activated, the lamellae having the activated adhesive are superimposed 3′ in a position-aligned and/or angularly aligned manner. A pressure ram 9 then applies a compressive force to the end face of the lamella stack 3′, which force axially compresses the laminated core. Preferably, a uniform surface pressure is exerted so that the force exerted in the axial direction is the same at every point on the end face.

[0153] Another embodiment is shown in FIG. 2. This differs from the embodiment shown in FIG. 1 in that no activation station 8 is provided. Instead, the number of lamellae coated at station 6 and inspected at station 7 are superimposed in a position-aligned and/or angularly aligned manner and the lamellae are heated and maintained at a temperature between 100° C. and 250° C. in a furnace 9 for a sufficiently long period of time, for example at least 30 minutes, to activate the adhesive. The compression of the laminated core by applying pressure with a ram 9 takes place at the same time.

[0154] Embodiments in which the entire method is carried out in an inline or continuous process are equivalent to the methods shown in FIG. 1 and in FIG. 2; in particular, there is no gathering of the lamellae in the stack 3, but rather the lamellae remain attached to one or more webs, in particular three webs on the metal sheet in order to be transported through the process by transporting the metal sheet. Furthermore, a continuous furnace can be used instead of the furnace 5, for example, and the lamellae can be removed from the metal sheet after step 8 (FIG. 1) or after step 7 (FIG. 2) by separating the webs using a so-called ejection punch known to a person skilled in the art. The processes are functionally equivalent as long as the boundary conditions required according to the invention or required for the developments are implemented by a person skilled in the art.