SHEET METAL FOR PRODUCING AN ELECTROMAGNETIC COMPONENT, IN PARTICULAR A STATOR CORE OR ROTOR CORE, AND METHOD FOR PRODUCING AN ELECTROMAGNETIC COMPONENT

Abstract

The invention relates to a sheet metal for producing an electromagnetic component, in particular a stator core or a rotor core, wherein the sheet metal is coated with an adhesive covering of a thermally activated adhesive. Said adhesive contains: 60 wt. parts of an epoxy resin in solid resin from, 0.5-15 wt. parts of a latent curing agent, 1-15 weight parts of a latent accelerator. The invention further relates to a method for producing an electromagnetic component.

Claims

1. Sheet metal for producing an electromagnetic component, in particular a stator core or a rotor core, wherein the sheet metal is covered with an adhesive covering of a thermally activated adhesive, wherein the adhesive contains: 60 wt. parts of an epoxy resin in solid resin form, 0.5-15 wt. parts of a latent curing agent, 1-15 wt. parts of a latent accelerator.

2. Sheet metal according to claim 1, wherein the adhesive contains: 1 to 10 wt. parts of a latent curing agent.

3. Sheet metal according to claim 1, wherein the epoxy resin is bisphenol A epoxy resin.

4. Sheet metal according to claim 1, wherein the latent curing agent contains a dicyandiamide, an imidazole, a BF3 amine complex or a combination thereof.

5. Sheet metal according to claim 1, wherein the adhesive contains: 1 to 10 wt. parts of a latent accelerator,

6. Sheet metal according to claim 1, wherein the adhesive furthermore has 0.2 to 8 wt. parts of absorption additives, selected from the group of lamp blacks and/or from the group of water-soluble dyes.

7. Sheet metal according to claim 1, wherein the latent accelerator contains a urea derivative.

8. Sheet metal according to claim 7, wherein the urea derivative is an N,N-dimethylurea or an N,N′-dimethylurea or a bifunctional urea derivative.

9. Sheet metal according to either claim 7, wherein an asymmetrically substituted urea is also or exclusively used as the urea derivative.

10. Sheet metal according to claim 1, wherein the urea derivative is a substance ##STR00003## where R: hydrogen or a group according to ##STR00004## where n=0 or 1, X=O or S, R1, R2 and R3: each hydrogen, a halogen, nitro group, a substituted or unsubstituted alkyl group, alkoxyl group, aryl group or aryloxyl group, R4: alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group, aralkyl group optionally substituted by a halogen, hydroxyl or cyano, R5: like R4 or alkoxyl group, R5 optionally forming a heterocyclic ring with R4, or an N,N-dimethyl-N′-(3,4-dichlorophenyl)urea or an N,N-dimethyl-N′-(3-chloro-4-methylphenyl)urea or an N,N-dimethyl-N′-(3-chloro-4-methoxyphenyl)urea or an N,N-dimethyl-N′(3-chloro-4-ethylphenyl)urea or an N, N-dimethyl-N′-(4-methyl-3-nitrophenyl)urea or an N-(N′-3,4-dichlorophenylcarbamoyl)morpholine or an N,N-dimethyl-N′(3-chloro-4-methylphenyl)thio-urea, the urea derivative is optionally 4,4′ methylene-bis-(phenyldimethylurea); or a mixture of two, three or more of the aforementioned.

11. Sheet metal according to claim 7, wherein the particles of the urea derivative have an average particle size between 1 μm and 30 μm.

12. Sheet metal according to claim 1, wherein the adhesive covering is applied to one or both sides of the sheet metal and has a thickness between 1 μm and 20 μm.

13. Sheet metal according to claim 12, wherein the adhesive covering consists of a first partial covering of the first sheet metal surface with a first thickness and a second partial covering of the second sheet metal surface with a second thickness, the first thickness preferably being at least 1.5 times, particularly preferably double the second thickness.

14. Sheet metal according to claim 1, wherein an insulating varnish layer is arranged between the sheet metal and the adhesive layer and/or only insulating varnish is arranged on the side opposite the adhesive layer.

15. Sheet metal according to claim 1, wherein the sheet metal is an electrical steel strip, in particular a non-grain-oriented electrical steel strip, or has been separated from a non-grain-oriented electrical steel strip.

16. Sheet metal according to claim 15, consisting, in addition to Fe and unavoidable impurities, of (all data in wt. %): 0.1-3.50 Si, 0.01-1.60 Al, 0.07-0.65 Mn, optionally up to 0.25 P.

17. Sheet metal according to claim 1, wherein the sheet metal is a soft magnetic, metallic material, for example consisting, in addition to Fe and unavoidable impurities, of (all data in wt. %): 0.1-4.0 Si, 0.01-2.60 Al, 0.07-3.0 Mn, optionally up to 0.5 P, optionally up to 0.015 B, optionally up to 0.2 Sb, optionally up to 0.01 Zn, optionally up to 5 Cr, optionally up to 5 Ni, optionally up to 0.25 V, optionally up to 0.5 Sn, optionally up to 0.01 As, optionally up to 0.3 Nb, optionally up to 0.5 W, optionally up to 0.85 Zr, optionally up to 0.2 Mo, optionally up to 1.0 Cu, optionally up to 0.5 Ti, optionally up to 0.5 C, optionally up to 0.01 Ce.

18. Sheet metal according to claim 15, having a thickness between 0.05 mm and 2.5 mm plus an adhesive covering.

19. Sheet metal according to claim 16, wherein the sheet metal is a sandwich or a sheet metal covered on one or both sides with an acoustically damping functional layer.

20. Method for producing an electromagnetic component, in particular a sheet metal core for an electrical machine, comprising the following steps: A) providing a sheet metal provided with an adhesive covering or a plurality of sheet metals provided with an adhesive covering according to claim 1, B) transporting the sheet metal into an inline system, comprising: a punching tool, means for outputting infrared radiation and an extrusion punch, C) punching a molded part designed as a stator lamella or as a rotor lamella from the sheet metal provided in step A with the punching tool, D) illuminating the adhesive covering of the molded part formed in step C with infrared radiation by means of the means for outputting infrared radiation to activate the adhesive covering of the molded part, D) extruding the molded part with the extrusion punch, E) positionally aligned and/or angularly aligned positioning of the molded part in a positioning region, F) repeating steps C) to E) until a desired number of molded parts has been reached in the positioning region.

21. Method according to claim 20, wherein the production of the component takes place in an inline process, the punching tool and the extrusion punch being part of the same press.

22. Method according to claim 20, wherein the means for outputting infrared radiation are arranged between the punching tool and the extrusion punch and have: at least one upper lamp which is directed in a punching direction onto a first molded part surface or at least one lower lamp which is directed against a punching direction onto a second molded part surface present on the other side of the punching tool or both at least one upper and at least one lower lamp.

23. Method according to claim 20, wherein after positioning the last molded part of the desired number of molded parts, the component obtained by means of a compaction step downstream of step F is compacted with an even surface pressure at the end.

24. Method according to claim 20, wherein steps C to E are carried out with a stroke rate of at least 80 /min.

25. Method for producing an electromagnetic component, in particular a sheet metal core for an electrical machine, comprising the following steps: A) providing a sheet metal provided with an adhesive covering or a plurality of sheet metals provided with an adhesive covering according to claim 1, B) punching a number of lamellae, in particular molded parts designed as stator lamellae or as rotor lamellae, from the sheet metal provided in step A with the punching tool, C) superimposing the molded parts in a positionally aligned and/or angularly aligned manner, D) pressing the superimposed molded parts, E) heating the superimposed molded parts for a predetermined period of time at a predetermined temperature, F) optionally, after positioning the last molded part of the desired number of molded parts, compacting the component obtained by means of a compaction step downstream of step E with an even surface pressure at the end in a direction perpendicular to the molded part surface.

26. Method according to claim 25, wherein the predetermined period of time is between 10 minutes and 60 minutes.

27. Method according to claim 25, wherein the predetermined temperature is between 100° C. and 200° C.

28.-32. (canceled)

Description

EXAMPLES

[0135] Examples of a sheet metal according to the subject disclosure and its advantageous behavior for the method according to the subject disclosure result from tests carried out.

[0136] The following samples were produced:

[0137] Printed circuit board made from electrical steel strip M800-50A (according to EN 10027-1) with the material code 1.0816 (according to EN 10027-2), thickness 0.5 mm, length×width: 200×150 mm.

[0138] Samples 0, 1, 2 and 3 were made. Samples 0, 1 and 2 are comparative samples, they are covered with an adhesive not according to the subject disclosure.

[0139] Sample 3 is a sample according to the present disclosure.

[0140] The samples produced are printed circuit boards of the type mentioned above, which have been covered with adhesive using an application roller according to the following parameters:

TABLE-US-00001 wt. parts of wt. epoxy resin parts of wt. Sample (present as curing parts of Selected designation solid resin) agent accelerator accelerator Sample 0 60 3.5 4.5 Conventional accelerator (DYHARD URAcc57, brand name) Sample 1 60 3.5 3.0 Conventional accelerator (DYHARD URAcc13, brand name) Sample 2 60 3.5 3.0 Conventional accelerator (DYHARD URAcc13, brand name) Sample 3 60 3.5 3.0 4,4′-methylene- bis- (phenyldimethyl urea)

[0141] Layer thicknesses

[0142] Sample 0: 1st surface: 6 μ, 2nd surface 0 μm,

[0143] Sample 1: 1st surface: 6 μm, 2nd surface 0 μm,

[0144] Sample 2: 1st surface: 4 μm, 2nd surface 2 μm,

[0145] Sample 3: 1st surface: 4 μm, 2nd surface 2 μm.

A plurality of specimens were made of each of the sample types. To test the long-term stability, 18 sandwich structures were made of two identical samples.

[0146] Two samples of the same type were bonded using a plate press with a plate area of 200 mm×200 mm with a surface pressure of 3 N/mm.sup.2, the adhesive being activated in an oven by heating to 120° C. and holding at 120° C. for 30 minutes. Then 8 samples were placed in an oven and stored there at 40° C. A sample was taken every week and a shear value test was performed (based on DIN EN 1465). In addition, a shear value test was performed every week on specimens stored at room temperature. The results of the test are shown in FIG. 1a and 1b.

[0147] It can be seen from the results that, at room temperature, the composition used according to the subject disclosure has better shear values than the reference samples sample 0, sample 1 and sample 2. Sample 0 tested after six weeks had a significantly reduced shear value; after 8 weeks, sample 0 had a shear value of 0.

[0148] Storage at 40 degrees Celsius results in a shear value of 0 for the reference sample 0 after one week at the latest, i.e. the sample has no storage stability at 40 degrees Celsius. After 2 weeks, sample 1 and sample 2 had an almost unchanged good shear value of over 7.0 N/mm.sup.2, but began to degrade noticeably after three weeks of storage.

[0149] In all cases, the shear value of sample 2 with a surface covered on both sides is higher than the shear value of sample 1 with a surface covered on one side.

[0150] In particular, it can be seen that sample 3 has the best storage stability with an almost unchanged good shear value after 4 weeks at 40 degrees Celsius storage. The only sample that could be obtained was a printed circuit board sandwich which, even after four weeks of storage at 40 degrees Celsius, still had an unchanged good shear value. At the time of application, the tests were still ongoing.

[0151] In addition, tests were carried out on the finished sandwiches, they were heated to test temperatures, then, after briefly holding them under heat, also subjected to a shear value test.

TABLE-US-00002 Shear values [N/mm.sup.2] Sample number mean value Sample 2 Sample 3 from 3-fold test Standard Standard in each case [N/mm.sup.2] dev. [N/mm.sup.2] dev. RT 5.55 0.88 6.01 0.26  50° C. 5.08 1.32 5.85 0.11 100° C. 5.38 0.27 5.59 0.12 150° C. 4.89 0.42 5.22 0.08 200° C. 4.66 0.46 4.96 0.04

[0152] The results show that both sample 2 and sample 3 can withstand high temperatures of up to 200° C. over a certain period of time without losing their mechanical stability. In particular, it can be seen that the shear values of sample 3 are significantly higher than those of comparison sample 2.

[0153] Sample 0 was subjected to the temperature test as a reference, it was shown that a shear value of about 0.90 N/mm.sup.2 was obtained after heating to 150° C. On the basis of sample 3, it was thus found that the sheet metals according to the subject disclosure are suitable for the production of more temperature-stable sheet metal cores compared to sheet metals that are already known.

[0154] An example of a first embodiment of the method for producing a sheet metal core for an electric motor is shown in FIG. 2a. A sheet metal already covered with a plastics material is provided, in particular as a non-grain-oriented electrical steel strip 1. This is transported into an inline system. In a first station, a number of extrusion punches 4 ensures that molded parts 2, which are designed as rotor lamella or stator lamella, are extruded. In a subsequent station, the molded part is illuminated by means of a means designed as an NIR emitter for outputting infrared radiation 5, and the resulting heating activates the adhesive covering of the molded part. The molded part is then extruded with the extrusion punch 6 and collected in a positioning region to form a stack 3 in a position-oriented and/or angular manner. Finally, in a compaction station, compaction with a compaction ram 7 takes place until the adhesive has cured and the finished sheet metal core can be removed.

[0155] FIG. 2b is a manufacturing process which is similar to the known baking varnish process. The method of FIG. 2b differs from the method of FIG. 2a in particular in that the molded parts 2 are extruded and the stack 3 is formed before the adhesive covering is activated. The adhesive is only finally activated in an oven 8, for example at a temperature between 100 and 200 degrees Celsius, with the sample being compacted by means of a stamp 7 at the same time.

[0156] It will be appreciated that various implementations of the above-disclosed and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.