DE102021211748A1 - Sheet metal laminate assembly and method of manufacturing a sheet metal laminate assembly - Google Patents

Abstract

The invention relates to a sheet metal laminate unit (100), the sheet metal laminate unit (100) comprising the following: two metal sheets (102, 112, 122) which are electrically insulated from one another; a support composite layer (104, 114) arranged between the metal sheets (102, 112, 122) and a stamped edge (150) limiting the surface extent of the sheet metal laminate unit (100).

Description

The present invention relates to the field of sheet metal laminates, in particular electrical sheet laminates, which are required for the assembly of rotors and stators for electrical machines.

Electrical laminations are used for assembling rotors and stators of rotating electrical machines. By using sheet metal laminates instead of solid iron material, eddy current losses are significantly reduced. This increases the efficiency of the machines. Undesirable eddy currents also occur to a significant extent in the event of incomplete mutual insulation of the electrical steel sheets.

Process for the production of a stack of sheets are from WO 2014/089593 A1 , the WO 2012/059588 A1 , the WO 2016/033630 A1 and the WO 2021/048175 A1 known.

From the WO 2017/174215 A1 a fine stamping process for stamping metal parts is known. A multi-layer base material with a number of individual layers lying one on top of the other is arranged and clamped partly between a stamping tool and a holding-down device and partly between a punch and a counter-stamp. The punch and the counter punch are moved relative to the punch and the blank holder. Several punched parts are cut and separated from the multi-layer base material.

The spread of electric motors in drive systems of vehicles is increasing rapidly. There is a great need to provide electric motors with high efficiencies quickly and with little effort.

The object of the present invention is to provide efficient electrical machines and their preliminary products and at the same time to provide them in a form that can be produced quickly using a simple production method.

The object is achieved according to the invention by the features of claim 1.

All metal sheets come into consideration as metal sheets with which a sheet metal laminate can be produced which can be used for the construction of a rotor or a stator. The laminations are, for example, electrical laminations, in particular comprising an iron-silicon alloy. It can be favorable if the sheets are produced by cold rolling and subsequent annealing.

The sheet thickness is not limited. Preferred metal sheets are each at least 0.03 mm, in particular at least 0.06 mm, e.g. at least 0.10 mm thick. Preferred metal sheets are each at most 0.60 mm, in particular at most 0.50 mm, e.g. at most 0.35 mm thick. Particularly preferred metal sheets are 0.03 to 0.60 mm thick, in particular 0.06 to 0.50 mm thick, for example 0.10 to 0.35 mm thick.

The yield point of the sheets can be in the range from 300 to 500 MPa, for example. The specified values refer to the 0.2% yield point, measured according to EN ISO 6892-1 .

The tensile strength of the sheets can each be in the range from 440 to 590 MPa, for example. She will according to EN ISO 6892-1 certainly.

The sheets are electrically isolated from each other. The supporting composite layer arranged between the metal sheets itself can be an electrically insulating supporting composite layer. The metal sheets can therefore be electrically insulated from one another by the supporting composite layer.

"Electrically isolated from each other" does not mean a complete electrical isolation that cannot be achieved in practice, but a degree of electrical isolation that is based on what is understood in the technical field of electrical sheet laminates as electrical insulation of electrical sheets with regard to normal operating voltages becomes.

However, an insulating layer, e.g. baked lacquer layer, can also be applied to at least one of the surfaces of the sheets. Such insulating layers formed from baked lacquer are common in sheet metal laminates for rotors and stators of electric motors and are known to those skilled in the art. The metal sheets can therefore be electrically isolated from one another by the insulating layer. The insulating layer can be, for example, a C5 or C3 quality insulating varnish. The insulating layer opens up the possibility of selecting the material for the supporting composite layer independently of its electrical conductivity. In addition, the insulating layer can develop an adhesion-promoting effect. The insulating layer can protect the metal sheets from corrosion, e.g. during transport to the place where the sheet metal laminates are manufactured.

The sheet metal laminate unit comprises two sheets. It can therefore be made up of two or more metal sheets. The sheet metal laminate unit is preferably made up of 2 to 20 sheets, in particular of 2 to 12 sheets, particularly preferably of 2 to 8 sheets, e.g. of 2 to 4 sheets.

If the laminated sheet metal unit is made up of more than two sheets, all of them are connected in the layer structure Nander adjacent sheets preferably electrically isolated from each other.

If the laminated sheet metal unit is made up of more than two sheets, a supporting composite layer is preferably arranged between sheets that are adjacent to one another in the layer structure.

The thickness of the support composite layer is not limited. It is preferably at least 1.0 µm, in particular at least 2.5 µm, for example at least 4 µm.

Thinner gauges can promote unwanted electrical contacts between sheets at punched edges. The minimum thicknesses specified here can therefore ultimately increase the efficiency of electrical machines that are manufactured using the sheet-metal laminate units according to the invention.

The thickness of the supporting composite layer is preferably at most 25 µm, in particular at most 16 µm, for example at most 10 µm. Greater thicknesses result in an increased proportion of support composite layer(s) in the overall thickness of the sheet metal laminate unit. Compliance with the maximum thicknesses specified here can ultimately increase the power density of electrical machines that are manufactured using the sheet metal laminate units.

The thickness of the support composite layer may be 1.0 to 25 µm, particularly 2.5 to 16 µm, for example 4 to 10 µm. With regard to the efficiency and the power density of electrical machines that are manufactured using the sheet metal laminate units, this can represent an optimum.

The thickness of the support composite layer can be 0.5 to 15% of the sheet thickness, for example 1 to 10% of the sheet thickness of the sheets between which the support composite layer is arranged, in certain sheet laminated units.

The information on the absolute and relative thicknesses of the supporting composite layer thus preferably also applies to at least one other protective layer or all other protective layers if there are a plurality of supporting composite layers in the sheet metal laminate unit.

The thickness of known insulating layers, e.g. baked lacquer layers, is significantly lower. The thickness thereof may be, for example, 0.5 to 5.0 µm, for example 1 µm to 4.5 µm. With certain insulating layers, however, it can be 0.5 to 2.0 µm, for example, preferably at most 1 µm. Its thickness can be, for example, 0.15 to 5%, for example 0.15 to 2%, of the thickness of the metal sheet to the surface of which the insulating layer is applied.

For example, a thickness of a supporting compound layer can be more than 4 μm and the thickness of an insulating layer can be at most 4 μm.

Information on the thickness of layers refers to the thickness in the sheet metal laminate in an area separated from the punching edge described in more detail below, i.e. in an area in which the layer thickness is not distorted and/or changed by the forces acting during punching.

The surface area of the laminated sheet metal unit is limited by a punched edge. The surface area of the laminated sheet metal unit is preferably limited all around by the punched edge. This means that the punched edge goes around the sheet metal laminate unit.

The surface area of the laminated sheet metal unit can be limited by a second punched edge.

The surface area of a preferred sheet metal laminate unit is limited outwards all around by a first punched edge and inwards all around by a second punched edge. Such sheet metal laminate units are obtained, for example, when a sheet metal laminate unit delimited on all sides by a first stamped edge is produced from a sheet metal laminate in a first stamping processing step and a (central) partial area is removed from it in a second stamping processing step.

This can also be done in a stamping processing step, e.g. when using a block die and a blank instead of a coil of sheet metal strip (coil). The circuit board is placed in the block cutting tool and the entire geometry is punched in one stroke.

The support composite layer may comprise a synthetic resin, preferably a phenolic resin, an epoxy resin, a melamine resin, a silicone resin, an organo-silicone resin or an acrylic resin; for example a phenolic resin, an epoxy resin, a melamine resin or an acrylic resin. Certain acrylic resins can have the disadvantage that they cannot be applied over the entire surface.

The Shore hardness of the supporting composite layer can be 10 to 100 Shore A, for example 10 to 60 Shore A. The Shore hardness is measured on a special sample. In this case, the supporting composite material is dried/vulcanized in such a layer thickness that a thickness is reached at which measurements can be carried out in accordance with standards and without the influence of the substrate.

The roller peel strength (DIN EN 1464) of the supporting composite layer is preferably at least 1.1 N/mm, in particular at least 1.7 N/mm, particularly preferably at least 2.5 N/mm, for example at least 3.0 N/mm.

The roll peel strength in the unit N/mm can correspond to at least twice, in particular at least three times, e.g. at least four times the thickness of the metal sheet closest to the supporting composite layer, measured in the unit mm. If the sheet metal is 0.2 mm thick, for example, the roller peel strength can be at least 0.4 N/mm, in particular at least 0.6 N/mm, e.g. at least 0.8 N/mm. If the sheet metal is 0.35 mm thick, for example, the roller peel strength can be at least 0.7 N/mm, in particular at least 1.05 N/mm, e.g. at least 1.4 N/mm. This is particularly true when the sheet is an electrical steel sheet comprising an iron-silicon alloy and/or when the electrical steel sheet is made by cold rolling followed by annealing.

The tensile shear strength of the supporting composite layer can be, for example, at least 3 N/mm, preferably at least 4 N/mm, particularly preferably at least 5 N/mm.

A preferred sheet metal laminate unit achieves electrical insulation of the sheets by adhering to the following equation (I) also across the punched edge in an edge area of the sheet metal laminate unit: $$\text{a}=\mathrm{\rho }1/\mathrm{\rho }2$$

In this equation, p1 is the apparent resistivity in an edge area of the sheet metal laminate unit. p2 is the apparent resistivity in an area of the sheet metal laminate unit remote from the edge area.

The quotient a is at least 0.001, preferably at least 0.005, particularly preferably at least 0.01, for example at least 0.02. It can also be at least 0.05, more preferably at least 0.15 or, for example, at least 0.30.

Measuring the apparent resistivity in a peripheral area of the sheet metal laminate assembly is one way to quantify the extent of undesired electrical contacts between sheets at the stamping edge. The less pronounced such electrical contacts between sheets are at the punched edge, the higher is the apparent specific resistance in the edge area.

To measure the apparent resistivity in an edge area of the sheet metal laminate unit, an edge piece is separated from the sheet metal laminate unit at the edge area in such a way that the area of the severed edge piece is one square centimeter and that the punched edge occupies one centimeter of the edge of the severed edge piece.

To measure the apparent resistivity in an area of the laminated sheet metal unit separated from the edge area, a reference piece, one square centimeter in size, separated from the punched edge, is separated from the laminated sheet metal unit.

The electrical resistances of the edge piece and the reference piece are measured in the thickness direction, i.e. orthogonal to the sheet planes. From the electrical resistances, the apparent resistivities are calculated in the usual way, taking into account the thickness of the pieces and the area of each one square centimeter.

The quotient a is calculated according to equation (I) from the apparent specific resistance p1 determined for the edge piece and the apparent specific resistance p2 determined for the comparison piece. If the thickness of the edge piece and the reference piece is approximately the same, the quotient a can also be calculated directly from the two measured electrical resistances.

The term "apparent" is used in connection with the specific electrical resistances, since undesired electrical contacts can exist particularly at the punched edge of the edge piece. Electrical current flows through these at certain points. The term "apparent" expresses the associated inhomogeneities.

When cutting off the edge piece and the comparative piece separated from the edge, care must of course be taken to ensure that no (additional) electrical contacts occur between the metal sheets at the (cut) edges formed in the process. The edge piece and reference piece can be separated, for example, by water jet cutting.

In a preferred sheet metal laminate unit, a first mass fraction of material other than sheet metal in an edge region of the sheet metal laminate unit is at least 20%, in particular at least 30%, particularly preferably at least 50%, e.g. at least 60%, of a second mass fraction of material other than sheet metal in one of the Stamping edge offset area of sheet metal laminate unit. This means that the material of the supporting composite layer and any other material present between the sheets during punching (and the associated high pressure) has not been displaced to a large extent in areas that are separated from the die edge.

The first mass fraction can be determined from the boundary piece described above. The mass of the edge piece is determined, then the metal sheets of the edge piece are separated from one another, the material portions other than sheet metal are removed and the remaining sheet metal portions are weighed again. Subtract the mass of the remaining sheet metal portions from the mass of the edge piece and calculate the first mass fraction by dividing the result of the subtraction by the mass of the edge piece.

The second mass fraction can be determined in the same way from the comparison piece described above.

The material other than sheet metal can be material of the supporting composite layer(s) and, if present, e.g. also material of the insulating layer(s).

A sheet metal spacing d1 between the sheets at the punched edge is preferably at least 10%, in particular at least 20%, more preferably at least 30%, particularly preferably at least 45%, e.g. at least 60%, of a sheet metal spacing d2 in a region of the sheet metal laminate unit that is offset from the punched edge. This also means that material of the supporting composite layer and any other material present between the metal sheets during the punching (and the associated high pressure) were not displaced to a large extent into areas that are separated from the punched edge.

The distances mentioned here can be determined, for example, in a section.

The thickness t1 of the laminated sheet metal unit at the punched edge can preferably correspond to at least 90%, in particular at least 100%, e.g. at least 105% of the sum of the thicknesses of the sheets in an area offset from the punched edge. Instead or in addition, the thickness t1 can be at most 110%, in particular at most 100%, e.g. at most 95% of the thickness t2 of the sheet metal laminate unit (100) in an area offset from the punched edge (150).

The thicknesses mentioned here can be determined, for example, in a section.

According to the invention, edge indentation and burring of the sheet metal ends at the punched edge are relatively small.

The burr of a metal sheet is preferably at most 0.08 mm, in particular at most 0.05 mm, for example at most 0.035 mm high. The height of the burr is measured orthogonally to the sheet surface and up to the sheet surface from which each burr protrudes.

The edge indentation of a metal sheet is preferably at most 0.14 mm, in particular at most 0.10 mm, e.g. at most 0.08 mm. Edge indent is measured orthogonal to the sheet surface and measured from the sheet surface from which each edge is indented.

Between the burr of one sheet and the drawn-in edge of the adjacent sheet, there is a curved course of the supporting composite layer, because the supporting composite layer inevitably carries out the deformations resulting from punching (burr formation and edge indentation) and isolates the burr of one end of the sheet from the adjacent sheet.

The invention also relates to a sheet metal laminate for producing a sheet metal laminate unit by stamping. The sheet metal laminate comprises the following: two metal sheets electrically insulated from one another and a support composite layer arranged between the sheets. The roller peel strength of the supporting composite layer is at least 1.1 N/mm, in particular at least 1.7 N/mm, particularly preferably at least 2.5 N/mm, e.g. at least 3.0 N/mm.

The tensile shear strength of the supporting composite layer can be, for example, at least 3 N/mm, preferably at least 4 N/mm, particularly preferably at least 5 N/mm.

The sheet metal laminate unit and/or the sheet metal laminate can have an insulating layer, e.g. The insulating layer, e.g. baked lacquer layer, is preferably composed differently than the supporting composite layer.

The invention also relates to a method having the features of claim 11 for manufacturing a sheet metal laminate unit.

Surprisingly, it was found that a sheet metal laminate unit according to the invention can be produced from a sheet metal laminate according to the invention by stamping without a counter punch. Unlike the teaching of WO 2017/174215 A1 suggests can be punched according to the present invention without a counter punch.

With a counterstamp, the clamping would first have to be adjusted before punching anyone the can. This is accompanied by comparatively slow punching speeds.

Without a counter punch, there is no need to wait for a clamp to be set before punching. Instead of 50 strokes/min, it can now be punched at 200 strokes/min.

The width of the cutting gap is preferably less than 20%, in particular less than 12%, e.g. less than 8% of the average thickness of the sheets of the sheet metal laminate.

It is assumed that the high roll peel strength of the supporting composite layer contributes to the fact that a stamping edge is obtained without a counter punch, essentially without the formation of undesirable electrical contacts between the sheets. Typical baked enamels are quite brittle and therefore cannot follow the movement of the metal sheet. It is believed that through increased adhesion within the support composite layer, a certain amount of deformation can be tolerated before failure occurs.

The invention also relates to a sheet metal laminate unit obtainable by the method according to the invention.

The invention also relates to the use of an adhesive in a sheet metal laminate to achieve less uneven edge distortion of the individual sheets of the sheet metal laminate at a punched edge.

It has been found that a uniform edge distortion can be achieved with adhesives. This can be due to the fact that the force transmission during cutting in the punching tool is transmitted by the adhesive from one sheet directly to the next sheet without the punched edges of the individual sheets being able to slip significantly against each other. For example, an edge indentation of a previously cut piece of sheet metal seems to be transferred to the next piece of sheet metal via the resulting burr.

The adhesive is preferably an adhesive that can be cured to form a supporting composite layer whose roll peel strength is at least 1.1 N/mm, in particular at least 1.7 N/mm, particularly preferably at least 2.5 N/mm, e.g. at least 3.0 N/mm . Common baking varnishes do not achieve such high roller peel strengths.

The invention also relates to the use of an adhesive in a sheet metal laminate for at least partially preventing the formation of electrical contacts between electrically insulated sheets of the sheet metal laminate at a punched edge.

It has been found that adhesives can be used in addition to or instead of conventional baking lacquers to reduce the formation of electrical contacts between electrically insulated metal sheets of the sheet metal laminate, including at punched edges.

A further aspect of the invention relates to the use of a punching device without a counter punch for punching a sheet metal laminate unit from a sheet metal laminate.

One aspect of the invention relates to a rotor core or a stator core, wherein the rotor core or the stator core comprises at least one sheet-metal laminate unit according to the invention.

One aspect of the invention relates to a rotor for an electrical machine, the rotor comprising a sheet metal laminate unit according to the invention.

One aspect of the invention relates to a stator for an electrical machine, the stator comprising a sheet metal laminate unit according to the invention.

Features of the invention that are described in connection with an object of the invention, i.e. in particular in connection with the sheet metal laminate unit according to the invention or the sheet metal laminate according to the invention, the method according to the invention or the uses according to the invention, preferably also apply to any other object of the invention.

Further preferred features and/or advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

• 1 einen vergrößert dargestellten Ausschnitt eines Schnitts durch eine Blechlaminateinheit;
• 2 eine stärker vergrößerte Darstellung des Bereichs der Stanzkante der in 1 gezeigten Blechlaminateinheit;
• 3 eine schematische vergrößerte Darstellung des Endes eines Blechs einer Blechlaminateinheit;
• 4 eine schematische Darstellung des Schichtaufbaus eines ersten Blechlaminats bzw. einer ersten Blechlaminateinheit;
• 5 eine schematische Darstellung des Schichtaufbaus eines zweiten Blechlaminats bzw. einer zweiten Blechlaminateinheit;
• 6 eine schematische Darstellung von Verfahrensschritten zur Herstellung eines Blechlaminats;
• 7 eine schematische Darstellung einer Feinstanzvorrichtung mit Gegenstempel;
• 8 eine schematische Darstellung einer Stanzvorrichtung ohne Gegenstempel.

In the drawings show:

• 1 an enlarged detail of a section through a laminated sheet metal unit;
• 2 a more enlarged representation of the area of the punching edge of the in 1 sheet metal laminate unit shown;
• 3 a schematic enlarged representation of the end of a metal sheet of a sheet metal laminate unit;
• 4 a schematic representation of the layer structure of a first sheet metal laminate or a first sheet metal laminate unit;
• 5 a schematic representation of the layer structure of a second sheet metal laminate or a second sheet metal laminate unit;
• 6 a schematic representation of process steps for the production of a sheet metal laminate;
• 7 a schematic representation of a fine blanking device with a counter punch;
• 8th a schematic representation of a punching device without a counter punch.

Identical or functionally equivalent elements are provided with the same reference symbols in all figures.

In 1 and 2 a section of a sheet metal laminate unit is shown. The sheet-metal laminate unit shown here comprises three sheets 102, 112 and 122. An electrically insulating supporting composite layer 104 is arranged between the sheets 102 and 112. A further electrically insulating supporting composite layer 114 is arranged between the metal sheets 112 and 122 . The surface area of the laminated sheet metal unit 100 is limited all around by the punched edge 150, with 1 and 2 Of course, only the part of the punched edge 150 that falls in the plane of the cut section can be seen.

The two electrically insulating support composite layers 104 and 114 each comprise a synthetic resin. The peel strength of the electrically insulating supporting composite layers 104 and 114 is at least 1.1 N/mm, particularly preferably at least 2.5 N/mm.

Especially in the enlarged representation of the 2 It is easy to see that, for example, a sheet metal spacing d1 between sheets 102 and 112 at punched edge 150, indicated by a double arrow, is essentially the same size as sheet metal spacing d2, also indicated by a double arrow, in a region of sheet metal laminate unit 100 that is offset from punched edge 150 The same applies to sheet metal distances between the sheets 112 and 122, these in 2 are not indicated for reasons of clarity.

p1 ist der apparente spezifische Widerstand in einem Randbereich der Blechlaminateinheit. p2 ist der apparente spezifische Widerstand in einem vom Randbereich abgesetzten Bereich der Blechlaminateinheit. In dem in 1 und 2 gezeigten Beispiel ist a annähernd 1. Die Isolationswirkung ist an der Stanzkante vom Stanzvorgang im Wesentlichen unbeeinflusst, da auch dort die benachbarten Bleche einen deutlichen Abstand einhalten.The clear mutual spacing of adjacent laminations, also at the stamping edge 150, avoids undesired electrical contacts between adjacent laminations, which, after further processing to form rotors and/or stators, would lead to undesired eddy currents during the operation of an electric motor. The sheet-metal laminate unit 100 shown here achieves electrical insulation of the sheets, ie also beyond the punched edge 150 . In this case, the following equation (I) is observed in an edge area of the sheet metal laminate unit (100): $$\text{a}=\mathrm{\rho }1/\mathrm{\rho }2$$

p1 is the apparent resistivity in an edge area of the sheet metal laminate unit. p2 is the apparent resistivity in an area of the sheet metal laminate unit remote from the edge area. in the in 1 and 2 a is approximately 1. The insulating effect at the punching edge is essentially unaffected by the punching process, since the adjacent metal sheets also maintain a clear distance there.

The clear mutual spacing of adjacent metal sheets at the punching edge is also likely to be due to the fact that material of the supporting composite layer 104, 114 was not displaced during punching (and the associated high pressure) into areas that are separated from the punching edge 150. The mass fraction of material other than sheet metal is therefore in a marginal area of the in 1 and 2 The sheet metal laminate unit 100 shown is essentially equal to the mass fraction of material other than sheet metal in a region of the sheet metal laminate unit which is offset from the punched edge 150 .

2 shows that the thickness t1 of the laminated sheet metal unit 100 at the punching edge 150 is approximately 108% of the sum of the thicknesses t102, t112 and t122 of the sheets 102, 112, 122 in an area separated from the punching edge (150). 2 also shows that the thickness t1 of the sheet metal laminate unit 100 at the punching edge 150 is approximately 91% of the thickness t2 of the sheet metal laminate unit (100) in a region offset from the punching edge (150).

How 2 also shows that the punched edge 150 is designed in such a way that a curved course of the supporting composite layers 104 and 114 towards the punched edge 150 results.

Out of 2 and especially the schematic one 3 shows that sheets 102, 112 and 122 also have an edge indentation KE-102, KE-112 or KE-122 and a burr G-102, G-112 or G-122 at the punched edge 150. However, the sheet metal laminates 200 appear to be able to be stamped with comparatively little edge infeed and little burr formation.

4 shows a schematic representation of the layer structure of a first sheet-metal laminate 200 or a first sheet-metal laminate unit 100. The embodiment shown here comprises two sheets 102 and 112, and an electrically insulating support composite layer 104 arranged between the sheets. Insulating layers 106 and 108 are on the surfaces of the sheet 102 and insulating layers 116 and 118 are attached to the surfaces of the sheet 112. FIG.

The insulating layers are each baked lacquer layers. These have a different composition than the composite support layer 104.

5 shows a schematic representation of the layer structure of a second sheet metal laminate 200 or a second sheet metal laminate unit 100. In comparison to the layer structure according to FIG 4 includes the in 5 embodiment shown includes a third sheet 122 attached over a second electrically insulating support composite layer 114 . Insulating layers 126 and 128 are also attached to the surfaces of sheet metal 122 . The insulating layers 126 and 128 are also baked lacquer layers, which have a different composition than the supporting composite layers 104 and 114.

According to 6 For example, a (non-hardened) precursor material of the supporting composite layers 104 and 114 can first be applied to the two surfaces of a sheet metal 112 on both sides in order to produce a sheet metal laminate. Sheets 102 and 122 can then be attached to these two surfaces, thus forming the sheet metal laminate. Precursor material of a third supporting composite layer 124 can be applied to one of the surfaces of the formed sheet metal laminate and a layer composite can be formed over this to form a further sheet metal or sheet metal laminate, not shown here. On one or both surfaces of the metal sheets 102, 112 and 124 used for production, for example baked lacquer layers or insulating lacquer layers of quality C5 can be applied as insulating layers.

7 shows a punching device 160 in the form of a fine punching device with stamp 170 and counter-stamp 180. It is, for example, from FIG WO 2017/174215 A1 known to process a multi-layer base material in such a fine blanking device. The base material is placed and clamped partially between a punch and a blank holder and partially between a punch 170 and a counter-punch 180 . The punch 170 and counter punch 180 are moved relative to the punch and blank holder. Several stamped parts are cut and separated from the multi-layer base material.

8th 12 shows a punching device 160. The method for producing the sheet metal laminate unit 100 can thus be carried out particularly efficiently. The laminated sheet metal unit 100 is produced by stamping from a laminated sheet metal 200 comprising three sheets and electrically insulating supporting composite layers (not shown here) between the sheets. Punching takes place without a counter punch 180. It is not shown here that the width of the cutting gap is preferably less than 20%, for example less than 8%, of the average thickness of the sheets of the sheet metal laminate. The peel strength of the electrically insulating supporting composite layers is at least 1.1 N/mm, particularly preferably at least 2.5 N/mm.

Reference List

100

sheet metal laminate unit

102

sheet

104

support composite layer

106

insulating layer

108

insulating layer

112

sheet

114

support composite layer

116

insulating layer

118

insulating layer

122

sheet

124

support composite layer

126

insulating layer

128

insulating layer

150

punching edge

160

punching device

170

Rubber stamp

180

countermark

200

sheet metal laminate

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2014/089593 A1 [0003]
• WO 2012/059588 A1 [0003]
• WO 2016/033630 A1 [0003]
• WO 2021/048175 A1 [0003]
• WO 2017/174215 A1 [0004, 0062, 0093]

Non-patent Literature Cited

• DIN EN ISO 6892-1 [0010, 0011]

Claims (14)

A sheet metal laminate assembly (100), the sheet metal laminate assembly (100) comprising: two metal sheets (102, 112, 122) electrically insulated from one another; a support composite layer (104, 114) disposed between the sheets (102, 112, 122), and a punched edge (150) limiting the surface area of the sheet metal laminate unit (100). sheet metal laminate unit (100) after claim 1 , characterized in that the support composite layer (104, 114) comprises a synthetic resin. sheet metal laminate unit (100) after claim 1 or 2 , characterized in that the roller peel strength of the support composite layer (104) is at least 1.1 N/mm, particularly preferably at least 2.5 N/mm. Sheet metal laminate unit (100) according to one of the preceding claims, characterized in that the sheet metal laminate unit (100) achieves electrical insulation of the sheets by complying with the following equation (I) also across the punched edge (150) in an edge region of the sheet metal laminate unit (100): $$\text{a}=\mathrm{\rho }1/\mathrm{\rho }2$$

where p1 is the apparent resistivity in an edge area of the sheet laminated unit, p2 is the apparent resistivity in an area of the sheet laminated unit remote from the edge area, and a is at least 0.001, eg at least 0.02. Sheet metal laminate unit (100) according to one of the preceding claims, characterized in that a first mass fraction of material other than sheet metal in an edge region of the sheet metal laminate unit (100) is at least 20%, e.g. at least 60%, of a second mass fraction of material other than sheet metal in one of the area of the laminated sheet metal unit (100) that is offset from the punched edge (150). Sheet metal laminate unit (100) according to one of the preceding claims, characterized in that a sheet metal spacing d1 between the sheets (102, 112, 122) at the punched edge (150) is at least 10%, e.g. at least 60%, of a sheet metal spacing d2 in one of the punched edge (150) remote area of the laminated sheet metal unit (100). Sheet metal laminate unit (100) according to one of the preceding claims, wherein the punching edge (150) is such that the thickness t1 of the sheet metal laminate unit (100) at the punching edge (150) is at least 90% of the sum of the thicknesses (t102, t112, t122) of the metal sheets (102, 112, 122) in an area separated from the punching edge (150) and is at most 110% of the thickness t2 of the sheet metal laminate unit (100) in an area separated from the punching edge (150). Sheet metal laminate (200) for producing a sheet metal laminate unit (100) by stamping, the sheet metal laminate (200) comprising the following: two sheets (102, 112, 122) electrically insulated from one another and a supporting composite layer (104, 114) arranged between the sheets, wherein the Roll peel strength of the supporting composite layer (104) is at least 1.1 N/mm, particularly preferably at least 2.5 N/mm. Sheet metal laminate unit (100) or sheet metal laminate (200) according to one of the preceding claims, characterized by an insulating layer (106, 108, 116, 118, 126, 128), e.g. baked lacquer layer, on at least one of the surfaces of the sheets (102, 112, 122) , wherein the insulating layer (106, 108, 116, 118, 126, 128), eg baked lacquer layer, has a different composition than the supporting composite layer (104, 114). A method of manufacturing a sheet metal laminate assembly (100) made from a sheet metal laminate (200) comprising: two metal sheets (102, 112, 122) and a supporting composite layer (104, 114) arranged between the metal sheets, a sheet metal laminate unit (100) is produced by stamping without a counter punch (180). procedure after claim 10 , wherein the width of the cutting gap is less than 20% of an average thickness of the sheets (102, 112, 122) of the sheet metal laminate. procedure after claim 10 or 11 , wherein the roll peel strength of the support composite layer (104, 114) is at least 1.1 N/mm, particularly preferably at least 2.5 N/mm. Use of an adhesive in a sheet metal laminate (200) to achieve less uneven edge distortion of the individual sheets (102, 112, 122) of the sheet metal laminate (200) at a punched edge (150). Use of an adhesive in a sheet metal laminate (200) to at least partially prevent the formation of electrical contacts between electrically insulated sheets (102, 112, 122) of the sheet metal laminate at a punched edge (150).

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