Adhesive packaging of rotor and stator packages

Description

[0001] The present invention relates to a device for joining sheet metal.

[0002] The present invention further relates to a system for joining sheets and a method for joining sheets.

[0003] Due to technological developments and political requirements, electromobility has become increasingly important in recent years. In vehicle production (cars, trucks, motorcycles, bicycles, etc.) as well as in other areas, the manufacturing process for electric motors, in addition to the development and production of batteries, is also a highly relevant factor.

[0004] The laminated cores contained in a rotor or stator of an electric motor comprise a multitude of thin laminations (also known as electrical laminations). These electrical laminations exhibit excellent properties in conducting and amplifying magnetic fields. The composition and stress-free state of the laminations, as well as their insulation from one another, influence the efficiency of the electric motor. In the manufacture of rotors and stators for electric motors, the term "lamination" refers to the joining of individual laminations to form a laminated core. A laminated core is, in particular, an ordered stack of a plurality of laminations that are connected to one another. Such a laminated core replaces a solid iron core and can lead to more powerful electric motors.

[0005] In the production of sheet metal stacks, the so-called punching and stacking process is primarily used. The sheets are punched out of a raw material, which is supplied on a roll, for example, in a punching process, placed in a stack, and then joined together. Various methods are used for joining. Welding processes can be used, in which weld seams are applied to connect individual sheets. Joining with adhesives or other methods is also possible.

[0006] In this context, EP 3 353 241 B1 discloses a thermally activatable, fast-curing adhesive coating. In particular, an adhesive composition for use in a process for producing a laminated core from bonded sheet metal components is described. The composition contains an aqueous dispersion containing 100 parts by weight of an epoxy resin, four to eight parts by weight of a latent curing agent, and four to ten parts by weight of a latent accelerator.

[0007] DE 10 2012 001 744 A1 discloses a method for producing a laminated core consisting of several stacked electrical steel sheets. In a device, an adhesive applied to the electrical steel sheet is activated under the influence of heat, and the electrical steel sheet is bonded to the laminated core under the influence of heat and pressure. Furthermore, the electrical steel sheet is punched from a sheet metal strip immediately before stacking or during stacking.

[0008] DE 10 2016 225 853 A1 discloses a method and a device for producing a laminated core from a plurality of individual sheets provided with a layer of adhesive at least on one side and over their entire surface. The individual sheets are stacked in alignment with one another and bonded to one another under the influence of pressure by means of the layer. The device comprises a punch, a pressure stamp, and an activation unit for the adhesive. The activation of the layer present on the individual sheet and applied over its entire surface only occurs in partial areas of this layer. A mask is arranged in the area at or within the activation unit. Alternatively, the device comprises a mask in the area of or within the activation unit. The device comprises an adhesive application unit for applying the adhesive to the sheet metal strip and / or a drying unit for expelling the solvent from the adhesive.

[0009] A disadvantage of previous approaches in this context is that bonding requires a comparatively complex process technology, which on the one hand leads to higher costs and on the other hand also reduces flexibility. For example, applying the adhesive as a dispersion by the manufacturer of the laminated core is often not possible or not efficient because, among other things, the necessary evaporation of the water significantly increases process times. This means that the sheets are usually already coated with reactive adhesives by the steel supplier and are purchased by the manufacturer of the laminated core in a pre-processed and, in particular, pre-coated form. This, in turn, often leads to limited flexibility, for example with regard to applying different coatings to the top and bottom sides.

[0010] Based on this, the present invention aims to provide an approach for joining sheet metal that enables a flexible and cost-effective process technology. In particular, it aims to enable faster processing compared to previous approaches. This should enable the efficient production of sheet metal stacks with the greatest possible independence from suppliers.

[0011] To achieve this object, the present invention relates in a first aspect to a device for joining sheets, with a feed unit for feeding a sheet and a carrier material with a pre-applied adhesive film in a thermoplastic-solid state; a connecting unit for connecting the sheet to the carrier material by means of the adhesive film by converting the adhesive film into a thermoplastic-adhesive state and pressing the carrier material and the adhesive film onto the sheet; a detachment unit for detaching the carrier material from the sheet, wherein the adhesive film on the sheet remains in a thermoplastic-solid state; a punching unit for punching the sheet with the adhesive film into a predefined sheet shape; an activation unit for activating the adhesive film on the sheet shape; a pressing unit for connecting several sheet shapes to produce a sheet stack by pressing.

[0012] In a further aspect, the present invention relates to a system for joining metal sheets, comprising a device as described above, a metal sheet and a carrier material with a pre-applied adhesive film.

[0013] Further aspects of the invention relate to a method for joining sheets designed according to the device and to an electric motor with a stator and / or rotor which comprises a laminated core produced according to the method.

[0014] Preferred embodiments of the invention are described in the dependent claims.

[0015] According to the invention, a sheet metal and a carrier material with a pre-applied adhesive film are fed to and received respectively. In a first process step, the sheet metal is joined to the carrier material, wherein the adhesive film is converted into a thermoplastic-adhesive state to establish the connection between the sheet metal and the carrier material, and the carrier material is pressed onto the sheet metal. The carrier material is then removed so that the adhesive film remains on the sheet metal. In the process, the adhesive film returns to a thermoplastic-solid state. The sheet metal with the adhesive film can then be punched into a predefined sheet metal shape. After the punching process, the adhesive film on the punched sheet metal shape can be activated, and several sheet metal shapes can be pressed together to join the several sheet metal shapes to form a sheet stack, wherein the adhesive film preferably converts or is converted into a duromer-solid state.Such a condition results in particular in thermal and media resistance, which is essential for applications in electric motors, for example.

[0016] In contrast to previous approaches, the bond between the sheet metal and the adhesive film is created directly before further processing and punching. This involves converting an adhesive film into a thermoplastic, adhesive state (tacky or sticky state) and applying it to a sheet metal without activation. The adhesive then remains in a thermoplastic, solid state. This bond achieves sufficient strength for punching without causing undesirable brittleness. The actual activation of the adhesive—if necessary—only takes place after the punching process and directly before pressing to produce the laminated core.

[0017] One advantage of this approach is that the adhesive does not have to be applied to the sheet as a dispersion, thus increasing productivity through reduced process times (particularly because the water contained in a dispersion does not require evaporation time). The fact that no dispersion is required simplifies or even enables the application of – possibly different – adhesives to the top and bottom surfaces. Furthermore, supplier and product independence is achieved because the application of the adhesive film is significantly accelerated and simplified. For example, in the interests of a compact production line, the adhesive application can be scheduled immediately upstream of the punching and packaging system. This makes it possible to process sheets with and without additional insulation layers, or with and without preservation or corrosion protection layers.Because the adhesive only needs to be applied to the sheets or steel coils immediately before the punching process, these steel coils can be stored for longer. Refrigerated storage of a (reactive) adhesive film may not be necessary, as is the case with steel coils with activated adhesive. Another advantage is that heavy loads on the adhesive (sheet metal coil weighing several tons), which can provoke the stickiness of an otherwise "solid" adhesive film and thus complicate unwinding of the coil, are avoided. Furthermore, flexibility in the choice of adhesive chemistry and the layer thicknesses used (e.g., top and bottom layers) is achieved. Provided the adhesive meets the requirements for thermal and media resistance of the final product, a non-reactive hot melt adhesive film, for example, can also be used.Finally, it is possible to extend a sheet, for example when changing a steel strip roll, as this can be done directly before coating, so that the coating is not affected.

[0018] In contrast to the state of the art, there is no pre-coating of the sheet; instead, the adhesive is applied directly to the carrier material before further processing. The carrier material increases the stability of a thin adhesive film. The carrier material prevents contamination of corrugations caused by the adhesion of an adhesive film. The processing of multiple sheets can be simplified.

[0019] In a preferred embodiment, the device comprises a further feed unit and a further connecting unit for feeding and connecting a further sheet and a further carrier material with a previously applied further adhesive film. The device further comprises a sheet connecting unit for connecting the sheet coated with the adhesive film to the further sheet and the further carrier material connected thereto by means of the further adhesive film to form a multiple sheet. The device further comprises a further detachment unit for detaching the further carrier material from the multiple sheet, wherein the further adhesive film remains in a thermoplastic-solid state on the multiple sheet. The punching unit is designed to punch the multiple sheet coated with the adhesive film into the predefined sheet shape.In other words, it is possible to join several sheets together before the punching process to create a multiple sheet. The sheet joining unit is used to stack or join several sheets and the adhesive films in between. The adhesive film between the sheets is converted into a thermoplastic, adhesive state so that the sheets are joined with sufficient strength for processing. The bottom or top layer remains covered by the carrier material to prevent the adhesive film from sticking to the shafts or rollers of the joining unit and the release unit. Directly before punching, the carrier material on the bottom or top sheet of the multiple sheet is also removed. In the punching unit, the multiple layers or the multiple sheet are then punched in one punching process.By joining multiple laminations, a corresponding laminated core can be manufactured more efficiently. In this respect, the present invention also enables the in-situ production of a two- or multi-laminated core directly before the punching process.

[0020] It goes without saying that by using additional corresponding units, more than two sheets can be connected. For example, three, four, or five sheets can be connected to form a multiple sheet. The corresponding units are connected in series. This results in further improved efficiency and increased flexibility. Furthermore, improved scalability and expandability are achieved.

[0021] In a preferred embodiment, the bonding unit comprises a calender, preferably a calender with a heatable roller, and / or a heating unit for heating the adhesive film. A calender, i.e., a system of multiple rollers, enables the processing of steel strip rolls. In particular, an efficient bond between the sheet and the carrier material is enabled. For example, the adhesive film can be converted into the thermoplastic-adhesive state by pressing. Immediately after the pressure is released, the adhesive film can then return to the thermoplastic-solid state, and the carrier material can be removed. Efficient, continuous processing can be achieved.

[0022] In a preferred embodiment, the joining unit is designed to join the sheet metal to the substrate by heating the adhesive film to a temperature below the adhesive film's activation temperature. Since the adhesive film is not activated when joining the sheet metal to the substrate or when applying the adhesive film to the sheet metal, it can be converted back into a thermoplastic-solid state after application, enabling further processing. In particular, the punching process can be carried out without contaminating the machine. The adhesive film is only activated after punching and directly before the sheets are joined in the pressing unit.

[0023] In a preferred embodiment, the punching unit is designed to punch the adhesive-coated sheet or the adhesive-coated multiple sheet into the shape of a stator sheet or a rotor sheet. The pressing unit is designed to connect multiple sheet shapes to form a rotor or stator laminated core for an electric motor. In particular, punching can be performed directly into a corresponding rotor or stator shape. This enables efficient production of electric motors using the device described above or the method according to the invention.

[0024] In a preferred embodiment, the activation unit is designed to activate the adhesive film by heating, in particular by infrared radiation, induction, hot air, resistive heating, microwaves, or dielectric heating. Additionally or alternatively, the activation unit is designed to activate the adhesive film by light, in particular UV light, or laser beams. Depending on the adhesive chemistry, different activation methods can be used. Activation takes place directly before the pressing process and after punching. The different approaches for activating the adhesive film allow for appropriate adaptation depending on the adhesive chemistry used or the required properties.

[0025] In a preferred embodiment, the punching unit comprises a progressive punching tool for punching the adhesive-coated sheet or the multiple adhesive-coated sheet in multiple steps. A progressive punching tool enables punching in multiple steps, with individual parts being cut or punched out in each step to produce the required shape (sheet metal shape) in multiple steps. This results in rapid processing and thus a higher process speed.

[0026] In a preferred embodiment, the feed unit and / or the further feed unit comprises a first receptacle for a sheet metal roll with wound sheet metal. Additionally or alternatively, the feed unit and / or the further feed unit comprises a second receptacle for a carrier roll with wound carrier material with a pre-applied adhesive film. The processing of sheet metal in the form of a wound sheet metal roll (also referred to as a strip steel roll or coil) enables efficient supply of the material. In particular, it is possible to procure the material in the form of a standard material, thus enabling manufacturer independence and cost reduction. The corresponding use of a wound carrier material with a pre-applied adhesive film can lead to manufacturer-independent supply of the adhesive. Furthermore, it is possible to achieve variability in the adhesive chemistry.This results in efficient processing.

[0027] In a preferred embodiment, the feed unit and / or the further feed unit is designed to feed a paper with a silicone coating, a plastic film, in particular a textile-reinforced plastic film, or a metal foil, in particular a siliconized metal foil, as the carrier material. The use of different carrier materials offers different advantages depending on the adhesive chemistry. In particular, a robust carrier material can achieve improved detachment of the carrier material from the sheet metal or from the adhesive film in the thermoplastic-solid state.

[0028] In a preferred embodiment, the feed unit and / or the further feed unit is designed to feed a carrier material with an adhesive film made of post-crosslinking and / or latently curing adhesive, in particular an epoxy resin. The use of such an adhesive film enables efficient processing by producing a thermoplastic adhesive state and a thermosetting solid state after activation. Furthermore, there are various adhesive films or different materials that exhibit such properties.

[0029] In a preferred embodiment, the feed unit and / or the further feed unit is designed to feed an electrical steel sheet for a rotor and / or stator core of an electric motor. Depending on the material used for the electrical steel sheet, different properties of the rotor and / or stator core can be influenced. In particular, there are specific electrical steel sheets that have properties relevant for certain applications. The device or method according to the invention enables great flexibility.

[0030] A sheet is understood here in particular to mean an electrical sheet, i.e. a thin sheet with good conduction and reinforcement properties with regard to electrical and magnetic fields. The sheet can comprise one or more insulating layers. However, it is also possible to use the method according to the invention for other types of sheet. An adhesive film is understood here in particular to be a film made of an adhesive that does not have to be applied as a dispersion. The carrier material can also be referred to as a carrier or liner. An adhesive state is understood to mean a tacky or sticky state in which the adhesive is not activated but nevertheless exerts an adhesive force. The adhesive film can in particular comprise a post-crosslinking or latently curing or reactive system. A sheet shape is understood to be a separate piece of sheet or a separate piece of a multiple sheet with a predetermined shape.

[0031] The invention will be described and explained in more detail below using some selected embodiments in conjunction with the accompanying drawings. Figure 1 shows a schematic representation of a system according to the invention for joining metal sheets; Figure 2 shows a schematic representation of a device according to the invention for joining metal sheets; Figure 3 shows a schematic representation of a metal sheet with a carrier material bonded thereto by means of an adhesive film, as well as a multiple metal sheet comprising two metal sheets; Figure 4 shows a schematic representation of the detachment of the carrier material from the metal sheet; and Figure 5 shows a schematic representation of a method according to the invention for joining metal sheets.

[0032] In the Figure 1An embodiment of a system 10 for joining metal sheets according to the invention is shown schematically. The system 10 comprises a device 12 for joining metal sheets, as well as a metal sheet 14 and a carrier material 16 with a pre-applied adhesive film.

[0033] In the illustrated embodiment, the sheet 14 and the carrier material 16 are fed in the form of coils. The carrier material 16 includes a pre-applied adhesive film. In a first process step, after the sheet 14 and the carrier material 16 have been fed into the feed unit 18, the sheet 14 is joined to the carrier material 16 (and the adhesive film) in the joining unit 20. For this purpose, the joining unit 20 in the illustrated embodiment comprises a calender 22. After passing through the calender 22, the carrier material 16 is detached from the sheet 14 by means of the detachment unit 24, after which the adhesive film on the sheet 14 remains in a thermoplastic-solid state.

[0034] Subsequently, in the illustrated embodiment, the sheet 14 is joined to another sheet 14' or another carrier material 16'. The additional sheet 14' and the additional carrier material 16' are joined by means of an additional feed unit 18' and a further joining unit 20'. Subsequently, the additional sheet 14', together with the additional carrier material 16' connected thereto, is joined to the adhesive-coated sheet 14 in a sheet joining unit 21 to form a multiple sheet. In the illustrated embodiment, the sheet joining unit 21 also comprises a calender 23 with corresponding shafts and rollers.

[0035] After detaching the additional carrier material 16' by means of the additional detachment unit 24', the multiple sheet is punched into a predefined sheet shape in a punching unit 26. In the illustrated embodiment, the punching unit 26 comprises a punching sequence tool 28. The adhesive film on the sheet shape is then activated by means of an activation unit 30. In a press unit 32, several of the punched sheet shapes are then connected to form a sheet stack 33 by pressing and preferably converting the adhesive film into a duromer-solid state.

[0036] The present invention is based in particular on the fact that no coating of a sheet is required, for example, by applying an adhesive as an aqueous dispersion. Instead, the adhesive is applied to a carrier material (also called a liner, such as release paper) and then applied to the sheet as a hot-melt adhesive. The liner initially remains on the adhesive film.

[0037] The adhesive film comprises, in particular, a hot-melt adhesive, which may contain additional additives. It may contain particles that can absorb radiation (e.g., in the infrared range) for rapid melting. Furthermore, the hot-melt adhesive can also be formulated reactively (e.g., thermally or by UV radiation) and additionally contain accelerators for rapid post-crosslinking. Activation is particularly necessary to achieve thermosetting properties of the solidified adhesive film. In this context, vitrimer-like properties can also be achieved, i.e., a covalent network can be formed or its topology can be altered through thermally activated bond exchange reactions.

[0038] To coat the sheet metal, the adhesive film (or adhesive foil) applied to the liner is guided over an activation unit (e.g., a laser diode array or a heated calender shaft) and then bonded to the sheet metal using a roller. Thanks to the carrier material, the shafts are not contaminated by the adhesive film during adhesive application. Furthermore, the carrier material increases the stability of the very thin adhesive film. With reactive adhesive films, the activation of the crosslinking reaction can also take place in this step or only after the electrical sheet has been coated.

[0039] If a two- or multi-sheet composite (sandwich) is to be created, two sheets are first bonded together with an adhesive film (compare Figure 1). The carrier material of the top or bottom composite is removed, and both sheets are bonded together by pressing. The carrier material of the bottom or top sheet remains until the sandwich composite enters the punching tool. The carrier material is only removed immediately before the subsequent punching tool or before joining with another sheet.

[0040] In Figure 1 In this context, the square brackets indicate that several additional sheets 14' or several additional carrier materials 16' can be connected. For example, a multiple sheet can be produced from three to five sheets. However, it is also possible for the inventive approach to be used with a single sheet.

[0041] In this way, it is possible to create multiple sheet metal joints that can then be fed into the punching tool or punching press as a composite. Since the adhesive is only applied shortly before punching, the coil and adhesive can be used separately and flexibly. This makes it possible to use different sheet materials (e.g. coated sheets with established insulation and corrosion-resistant layers). In particular, manufacturer independence is achieved. Furthermore, there is no need to store or transport coils coated with adhesive in a latently reactive state. This is important because coils are considerably heavier than the adhesive, and because of separate storage and transport, the cooling of the adhesive film that may be necessary can be eliminated, thereby increasing energy efficiency.

[0042] A further disadvantage of other technologies that use pre-coated coils is that the high pressure acting on the latently reactive adhesive coating can lead to premature curing of the adhesive or increased stickiness, which can complicate unwinding. This leads to significant process disruptions. Furthermore, the approach described can enable the application of different adhesives or different adhesive chemistries. With multiple sheets, it is also possible to use different adhesives or adhesive chemistries in the individual layers.

[0043] In the Figure 2A device 12 according to the invention for joining sheet metal is shown schematically. The device comprises a feed unit 18, a joining unit 20, a detachment unit 24, a punching unit 26, an activation unit 30, and a pressing unit 32. Furthermore, the device 12 optionally comprises a further feed unit 18' and a further joining unit 20', as well as a sheet metal joining unit 21 and a further detachment unit 24'. The various units can be designed individually or in combination. In particular, a combined unit can combine or fulfill the functions of two or more of the described units.

[0044] The device 12 according to the invention or the system 10 according to the invention can be used in particular in the production of laminated cores for stators or rotors of an electric motor. This results in potential savings and increased flexibility.

[0045] The feed unit 18 or the further feed unit 18' can in this respect be particularly suitable for feeding an electrical sheet for a rotor and / or starter laminated core of an electric motor. Such an electrical sheet can be received in particular via a sheet metal roll with wound sheet. In particular, the feed unit 18 can comprise a corresponding receptacle and be designed to receive a roll. It is further advantageous for the feed unit to comprise a second receptacle for a carrier roll with wound carrier material with pre-applied adhesive. In this respect, the carrier material can also be received in wound form or in roll form.

[0046] The carrier material, or liner, acts as a separating layer. The adhesive must not adhere (permanently) to the carrier material, but remains on the sheet after joining in the joining unit. Papers with a silicone coating, for example, can be used as the carrier material. If these are not sufficiently strong and tear during the process, it is also possible to use low-energy and possibly reinforced plastic films (e.g., with a textile carrier) or appropriately coated multi-metal foils.

[0047] The adhesives can be applied to the substrate by rolling, doctor blades, or spraying. The liquefaction for this initial processing can be achieved by melting, dispersing, or dissolving. After solidification or evaporation, the adhesive forms a thermoplastic, dry, and non-adherent coating. The adhesive can be applied to the substrate in various ways.

[0048] The adhesive is transferred from the carrier material to the electrical steel sheet during the process. In order for it to adhere to the sheet, the adhesive must be designed in such a way that it can be transformed from a solid form (thermoplastic-solid state) into a sticky or adhesive state (thermoplastic-adhesive state). At this stage, the adhesive film is still meltable, as is generally the case with thermoplastics, and can therefore still be classified as a thermoplastic. However, the high temperature and media resistance required for electric motors can usually only be achieved with thermoset plastics. Therefore, an adhesive system is used that can be activated in such a way that it becomes tacky again, but also undergoes chemical crosslinking or curing to form a thermoset (thermoplastic-solid state).After complete curing, the adhesive then exhibits the required properties with regard to high final strength. In particular, a post-curing, latently curing, or reactive system can be used as the adhesive. Epoxy resins, for example, can be used. Alternatively, phenols, polyesters, acrylates (possibly even systems produced using the no-mix process with separate coating of the top and bottom surfaces), urethanes / ureas, and bismaleimides can be used. Post-curing can be thermal (e.g., by MIR irradiation) or photo-initiated by irradiation in the visible or UV range. Post-curing is understood, in particular, to mean that the resulting thermoset material is a thermoset. However, it is also conceivable – for example, with acrylates – that they only then begin to cure (and are / remain thermoplastic).

[0049] The bonding unit 20 or the further bonding unit 20' can, in particular, comprise a calender press. The adhesive film can be converted from an original thermoplastic-solid state to a thermoplastic-tacky or adhesive state by applying pressure or by directly applying heat. For this purpose, a calender with a heatable roller or shaft can be used, for example. A separate heating unit, such as a heating wire or the like, can also be provided to enable the necessary heating.

[0050] The sheet metal joining unit 21 serves to join the sheet metal coated with the adhesive film to the other sheet metal. For this purpose, the sheet metal joining unit 21 can, in particular, also comprise a calender with corresponding shafts and rollers.

[0051] The detachment unit 24 and the additional detachment unit 24' serve to detach the carrier material from the sheet metal. In particular, it is preferably only necessary to peel the carrier material from the sheet metal, since the adhesive chemistry of the adhesive film is selected accordingly so that the adhesive remains on the sheet metal, particularly if appropriate pressure was previously applied. The detachment unit 24 and the additional detachment unit 24' can be understood in particular as a mechanical component by which the carrier material is guided away or removed from the sheet metal and the adhesive film remaining thereon after passing through the connecting unit 20.

[0052] The punching unit 26 serves to punch the adhesive-coated sheet or the multiple sheet. As described above, the punching unit can, for example, comprise a punching sequence tool that enables punching into a corresponding shape of a stator sheet or a rotor sheet in several steps.

[0053] Subsequently, the adhesive film on the punched sheet metal form is activated in the activation unit 30. For this purpose, the activation unit 30 can, for example, comprise a unit for heating the adhesive film. In particular, an infrared radiator or a hot air unit can be provided as the activation unit 30 directly in front of the pressing unit 32. It is also possible for the adhesive film to be activated by light, in particular UV light.

[0054] Finally, in the press unit 32, several sheet metal shapes are connected by a pressing process, wherein the press unit 32 can in particular comprise a hydraulic press.

[0055] In the Figure 3 A sheet 14 is schematically shown above, which is connected to a carrier material 16 by means of an adhesive film 38 (top). Furthermore, in Figure 3 Below, a multiple sheet is shown, which in the illustrated embodiment comprises a sheet 14, an adhesive film 38, a further sheet 14', a further adhesive film 38' and a further carrier material 16'.

[0056] In Figure 4 It is schematically shown that the carrier material 16 is removed from the sheet 14 and the adhesive film 38 remaining thereon by a shaft 40, which can in particular correspond to the detachment unit.

[0057] In the Figure 5A method according to the invention for joining metal sheets is shown schematically. The method comprises steps of feeding S10 a metal sheet and a carrier material, joining S12 the metal sheet to the carrier material, detaching S14 the carrier material from the metal sheet, punching S16 the metal sheet coated with the adhesive film, activating S18 the adhesive film on the metal sheet form, and joining S20 several metal sheet forms. The method can be used in particular as an operating method for a production plant for rotor and stator laminated cores.

Claims

1. Apparatus (12) for connecting metal sheets (14), comprising: a feed unit (18) for feeding a metal sheet and a carrier material (16) with a pre-applied adhesive film (38) in a thermoplastic-solid state; a connection unit (20) for connecting the metal sheet to the carrier material by means of the adhesive film by transforming the adhesive film into a thermoplastic-adhesive state and pressing the carrier material and the adhesive film onto the metal sheet; a detachment unit (24) for detaching the carrier material from the metal sheet, wherein the adhesive film on the metal sheet remains in a thermoplastic-solid state; a punching unit (26) for punching the adhesive film-coated metal sheet into a predefined metal sheet shape; an activation unit (30) for activating the adhesive film on the metal sheet shape; and a pressing unit (32) for connecting multiple metal sheet shapes to produce a metal sheet package (33) by pressing.

2. Apparatus (12) according to claim 1, wherein the pressing unit (32) is designed to produce the metal sheet package (33) by pressing and transforming the adhesive film (38) into a thermoset-solid state.

3. Apparatus (12) according to one of the preceding claims, comprising: a further feed unit (18') and a further connection unit (20') for feeding and connecting a further metal sheet and a further carrier material (16') with a pre-applied further adhesive film (38'); a metal sheet connection unit (21) for connecting the adhesive film-coated metal sheet (14) to the further metal sheet and the further carrier material connected thereto by means of the further adhesive film to form a multi-metal sheet; and a further detachment unit (24') for detaching the further carrier material from the multi-metal sheet, the further adhesive film remaining in a thermoplastic-solid state on the multi-metal sheet, wherein the punching unit (26) is designed to punch the adhesive film-coated multi-metal sheet into the predefined metal sheet shape.

4. Apparatus (12) according to one of the preceding claims, wherein the connection unit (20) comprises a calender (22), preferably a calender with a heatable roller, and / or a heating unit for heating the adhesive film (38).

5. Apparatus (12) according to one of the preceding claims, wherein the connection unit (20) is designed to connect the metal sheet (14) to the carrier material (16) by heating the adhesive film (38) to a temperature which is below an activation temperature of the adhesive film.

6. Apparatus (12) according to one of the preceding claims, wherein the punching unit (26) is designed to punch the adhesive film-coated metal sheet (14) or the adhesive film-coated multi-metal sheet into a shape of a stator metal sheet or a rotor metal sheet; and the pressing unit (32) is designed to connect multiple metal sheet shapes to a rotor- and / or stator-metal sheet package for an electric motor.

7. Apparatus (12) according to one of the preceding claims, wherein the activation unit (30) is designed to activate the adhesive film (38) by heating, in particular by infrared radiation, induction, hot air, resistive heating, microwaves or dielectric heating; and / or to activate the adhesive film by light, in particular UV light or infrared light, or laser radiation.

8. Apparatus (12) according to one of the preceding claims, wherein the punching unit (26) comprises a punching follow-on tool (28) for punching the adhesive film-coated metal sheet (14) or the adhesive film-coated multi-metal sheet- in several steps.

9. Apparatus (12) according to one of the preceding claims, wherein the feed unit (18) and / or the further feed unit (18') comprises a first receptacle for a steel roll with a wound metal sheet (14); and / or a second receptacle for a carrier roll with wound carrier material (16) with a pre-applied adhesive film (38).

10. Apparatus (12) according to one of the preceding claims, wherein the feed unit (18) and / or the further feed unit (18') is designed to feed a paper with silicone coating, a plastic film, in particular a textile-reinforced plastic film, or a metal foil, in particular a siliconized metal foil, as carrier material (16).

11. Apparatus (12) according to one of the preceding claims, wherein the feed unit (18) and / or the further feed uniting (18') is designed to feed a carrier material (16) with an adhesive film (38) of post-crosslinking and / or latent-curing adhesive, in particular an epoxy resin.

12. Apparatus (12) according to one of the preceding claims, wherein the feed unit (18) and / or the further feed unit (18') is designed to feed an electrical metal sheet for a rotor- and / or stator-metal sheet package of an electric motor.

13. System (10) for connecting metal sheets (14), comprising an apparatus (12) according to one of the preceding claims, a metal sheet and a carrier material (16) with a pre-applied adhesive film (38).

14. Method for connecting metal sheets (14), comprising the steps of: feeding (S10) a metal sheet and a carrier material (16) with a pre-applied adhesive film (38) in a thermoplastic-solid state; connecting (S12) the metal sheet to the carrier material by means of the adhesive film by transforming the adhesive film to a thermoplastic-adhesive state and pressing the carrier material and the adhesive film onto the metal sheet; detaching (S14) the carrier material from the metal sheet, whereby the adhesive film remains on the metal sheet in a thermoplastic-solid state; punching (S16) the adhesive film-coated metal sheet into a predefined metal sheet shape; activating (S18) the adhesive film on the metal sheet shape; and connecting (S20) multiple metal sheet shapes to produce a metal sheet package (33) by pressing.