Method for manufacturing a laminated core, laminated core and electric machine

Abstract

The invention relates to a method for manufacturing a laminated core, such as a stator core or a rotor core. The method comprises the following steps: A) providing a sheet material (1) having an adhesive coating; B) transporting the sheet material into an in-line facility comprising: a cutting device (4), a separating device (6) and an activation device (5, 5a, 5b); C) cutting the moldings (2) with the cutting device (4); D) activating the adhesive coating; E) separating the moldings (2); F) placing the moldings (2); G) repeating steps C) to F) wherein the adhesive coating of some moldings (2) is equipped with a treatment fluid by means of a treatment device (9) in order to allow a nominal breaking point for separating the molding stack (3, 3'). In some cases, a re-pressing with a press station (7) can be carried out. In addition, the invention relates to a laminated core and to an electric machine.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for manufacturing a laminated core. The invention further relates to a stack section of a laminated core and to an electric machine.

[0002] BACKGROUND

[0003] The functioning of electric machines and in particular electric motors in different ways has been known for a long time. Electric motors are gaining in importance not only in the context of the increasing use of electric motors in individualized private transportation, but also often with the catchword of electric cars. An important component of each electric motor is the stator and the rotor, wherein the term "stator" refers to the stationary part of the motor and the term "rotor" refers to the moving part of the motor.

[0004] A challenge in providing electric motors is to increase the efficiency of the electric motor, for example the provided unit volume power and / or the efficiency, at economically reasonable expenditure.

[0005] The idea for providing a highly efficient electric motor is to manufacture the stator and / or the rotor or parts of the stator and / or the rotor as a so-called stator core or rotor core. Other components to be manufactured are pole cores or commutator segments. Here, the components are composed of individual so-called sheets as a laminated core, also referred to as sheet pack. The term "sheet" refers to a molded piece, for example taken from an electrical steel sheet or an electrical steel strip, for example by means of punching. The sheet pack is composed of a plurality of thin sheets, which are stacked on top of one another and are electrically insulated from one another, partially or preferably completely. For such purposes, the use of, for example, so-called electrically insulating lacquers is known from practice, which are assigned to so-called insulation classes.

[0006] The manufacture of such a laminated core always comprises the steps of manufacturing the sheets and connecting the sheets to one another. Here, the connection is preferably made in such a way that after the connection the sheets are partially, preferably completely, electrically insulated from one another, i.e. preferably two adjacent sheets are not electrically connected to one another.

[0007] The production of individual laminations can be achieved, for example, by stamping. The stamped laminations can be joined to form a laminated core by various known methods, for example by screwing, by means of a setting jig, by welding or by stamping stacking. However, each of these production methods familiar to the person skilled in the art mentioned above is accompanied by an adverse effect on the prevailing electromagnetic properties of the finished laminated core after the joining, as a result of the mechanical action occurring during the joining. Mechanical stresses, which in particular adversely affect the magnetic properties and the magnetic flux path within the laminated core, and thus, for example, directly the efficiency of the electric motor produced therefrom, are inevitably at least to some extent unavoidable during the joining according to the prior art. The electrical connection between two or more laminations occurring in several joining methods, for example stamping stacking or welding, leads to additional losses.

[0008] A clever solution to reduce the adverse effects of mechanical action on the laminations and at the same time to achieve a good insulation between the laminations is the use of an adhesive as a joining means. Suitable adhesive systems often also have insulating properties similar to those of an electrical insulating varnish.

[0009] In this connection, a process known to the person skilled in the art is the use of so-called baking varnishes. The use of a baking varnish for bonding stamped electrical steel laminations is described, for example, in DE 38 29 068 C1. A process using a baking varnish is: coating the sheet material, in particular the sheet material strip; subsequently stamping individual laminations from the sheet material; positioning the individual laminations aligned relative to one another; and subsequently heat treating the resulting sheet material stack for a defined period of time and at a defined temperature. In many cases, during the heat treatment, the laminations are compressed relative to one another, for example by applying a force on the end face side in the direction of the axial direction of the laminated core pointing into the interior of the laminated core, preferably with a uniform surface pressure. Typical reaction temperatures are 150 to 250°C, typical baking varnish reaction times are 30 to 150 minutes, followed by a cooling phase, wherein the precise parameters are naturally dependent on the specific baking varnish used and the specific geometry present, since, for example, the core temperature occurring in the component influences the progress of the baking varnish process. In general, by this process, excellent electromagnetic properties of the stator core and / or rotor core can be achieved. However, it is immediately apparent that the use of a baking varnish is not suitable or at least not the most suitable for continuous mass production due to the time-consuming procedure. SUMMARY

[0010] Against the background of the situation set out, it is an object of the present application to create prerequisites for the efficient production of a laminated core, i.e. in particular a stator core or a rotor core, in a production environment.

[0011] Additionally, in the context of the desire to further improve efficiency, the present invention also aims to provide electromagnetic components and motors in which the conversion of electromagnetic energy to mechanical energy or vice versa is improved.

[0012] This objective is achieved through a method, a stacked section of laminated iron core, and an electric motor.

[0013] The method for manufacturing laminated iron cores for electric motors according to the present invention includes at least the following steps:

[0014] A) Provides a sheet material equipped with an adhesive coating that can at least partially harden. This means that the sheet material has an adhesive coating that hardens upon activation, such as by heat triggering, and thereby exerts its adhesive properties. The adhesive coating is a polymer-based adhesive coating. Preferably, the entire surface of the sheet material is coated with the adhesive coating (single-sided or particularly preferably double-sided). The sheet material may be, for example, an electrical steel strip or a slab separated from a strip.

[0015] B) Transporting the sheet material to the in-line facility. The in-line facility includes at least: cutting equipment, separating equipment, and activation equipment for activating the adhesive coating. The activation equipment is preferably arranged between the cutting equipment and the separating equipment.

[0016] The term "in-line facility" refers to a facility in which multiple processing stations are arranged in a predetermined order, i.e., at least those mentioned above, and where sheet metal, such as electrical steel strip, is processed automatically and sequentially in predetermined stations.

[0017] Cutting equipment is used to form the structure of a sheet to be manufactured. This can be achieved, for example, in multiple steps by a single cutting device or in multiple steps by different cutting devices. In both cases, it is preferable to achieve the multi-step structure formation in the sheet from the inside out, i.e., preferably by pre-setting a certain number of necessary cutting processes such that the cutting process first forms the innermost structure of the sheet and then gradually moves towards the outside of the sheet.

[0018] The cutting equipment can be designed as a die, for example. In this case, the cutting in step C) is stamping.

[0019] The cutting equipment can also be designed as a laser. In that case, the cutting in step C) is laser beam cutting.

[0020] The in-line facility may also include a series of multiple cutting devices, such as a stamping tool designed to include multiple sequentially arranged stamping stages or a sequence of stamping tools and lasers. At least one cutting device may be designed as a continuous compound tool by which a sheet of predetermined geometry is stamped into an electrical steel strip, preferably from the inside of the sheet to the outside.

[0021] In the context above, the term "sheet" refers to a molded part obtained by separating it from sheet metal, particularly a molded part obtained by punching.

[0022] The activation device for activating the adhesive coating is capable of introducing heat input into the adhesive coating, wherein, in principle, the heat input can be generated in any manner. In particular, the activation device may include a device for emitting infrared radiation, such as an NIR emitter, i.e., an irradiation device designed to emit electromagnetic radiation in the NIR wavelength spectrum, i.e., electromagnetic radiation with wavelengths between 400 nm and 10 μm, preferably between 780 nm and 3 μm.

[0023] Alternatively or additionally, the activation device may include an induction heating device, particularly an induction coil, for heating the adhesive coating.

[0024] Furthermore, as mentioned, the in-line facilities include a separation device. This separation device is preferably designed as a die that sequentially separates the sheet from the sheet defining its outer edge by a force effect perpendicular to the sheet surface, and preferably, in the same process step, conveys the sheet to a receiving device arranged below the sheet, where the sheet is collected. Preferably, the die punches the sheet off its outer boundary from the sheet. Particularly preferably, the cutting device and the separation device are components of the same press, which has the advantage of a high degree of synchronicity between the punching and extrusion processes.

[0025] C) Using a cutting device, molded parts, such as rotor or stator laminations, are cut (e.g., punched in one or more steps) from the sheet metal provided in step A. In an in-line facility, electrical components, particularly molded parts designed as stator or rotor laminations, are cut from the sheet metal provided in step A) using a cutting device, preferably before the outer contour is formed, but only in step E). In this case, immediately following step C), the molded part has all contours except its outer contour. Alternatively, an embodiment can be pre-defined in which the cutting of the molded part also includes the cutting of the outer contour.

[0026] D) The adhesive coating is activated, preferably across the entire surface, using an activation device for activating the adhesive coating of the molded part. Preferably, the activation of the molded part formed in step C) is achieved after the cutting in step C). The adhesive coating is activated by heat input, and the stamped molded part allows for adhesive bonding, i.e., pre-fixation. The term "pre-fixation" means that the molded part has sufficient load-bearing capacity for further processing, but not sufficient fixation for the industrial application of the finished laminated core. The adhesive bond is at least partially chemically hardened, and its final strength can be increased in a later process by repressing under pressure and / or temperature.

[0027] In one particular implementation, the activation temperature in the in-line facility can be preset to be between 30 degrees Celsius and 180 degrees Celsius, preferably between 40 degrees Celsius and 120 degrees Celsius, and particularly preferably between 50 degrees Celsius and 100 degrees Celsius.

[0028] E) Separate the molded parts using a separation device, and as step F), place (preferably guided by external geometry) the molded parts into a positioning area to form a stack of molded parts. The positioning area is used to position the molded parts onto other existing molded parts within the positioning area, aligning their positions and / or corners. Thus, one molded part after another is sequentially added to eventually obtain a stack of molded parts aligned with each other and equipped with activated adhesive. Preferably, the separation of the sheet from the sheet material using a separation device is achieved within the same process step as placing the molded parts into the positioning area, which is preferably implemented as punching, i.e., preferably, in the same process step and by guiding and, if necessary, applying pressure to the formed stack of molded parts by the separation device, the separation of step E) and the placement of step F), which preferably involves bonding the sheet to the corresponding preceding sheet, are achieved.

[0029] The positioning area can be, for example, a cylindrical tube adapted to the external geometry of the molded part; for example, for a molded part inscribed in a circle, this refers to a cylindrical tube located below the delivery plane of the molded part. Alignment of the molded part is achieved through the positioning area, which is, for example, designed as a hollow cylindrical tube with a sheath cross-section that substantially corresponds to and is aligned with the cross-section of the molded part by a predetermined positioning. The positioning area can also correspond to a molded image of a sheet and thus be in full-surface contact with the positioning area.

[0030] G) Repeat steps C) to F) in a preset order, such as C)->D)->E)->F) or C)->D)->E) together with F), wherein the molded parts are continuously stacked, i.e., the molded parts are continuously positioned in the positioning area. Preferably, this process is carried out such that the positioning area is continuously and completely filled.

[0031] The process can also be multi-row, i.e., two or more sheets are punched out in parallel and / or sequentially from electrical steel strips (diagonally staggered or rotating relative to each other, depending on the quantity, geometry and arrangement).

[0032] When a predetermined number of molded parts is reached, a processing device is used to supply processing fluid to the next molded part, at least in sections, thereby reducing the effect of the adhesive coating, i.e., the adhesive strength; that is, it has less adhesive strength or no adhesive strength at all. This makes it easier for the stacked sections below the reduced adhesive coating to separate from the stacked sections above the reduced adhesive coating at that location. Separability exists at the adhesive coating, such that the adhesive coating is provided with a rated break point at which the sheets directly adjacent to the adhesive coating can be easily separated from each other.

[0033] In other words, during the continuous repetition of steps C) to F), the selected molded part is coated with a processing fluid at least in sections by means of a processing device, thereby reducing the effect of the adhesive coating on the selected molded part, i.e., the adhesive strength, and making it easier to separate the stacked body sections located below the reduced adhesive coating from the stacked body sections located above the reduced adhesive coating. As a selected molded part, a molded part is selected such that, as the process continues, the correspondingly generated stacked body sections can be separated from the positioning device from below the receiving side of the positioning device with a desired number of molded parts and thus a desired molded part height, and thereby provided as a laminated iron core.

[0034] Therefore, a molded part stack is continuously formed, which is subdivided into stacked part segments, wherein preferably, stacked part segments are separated from the molded part stack as laminated iron cores.

[0035] For example, it can be preset that as each molded part is placed on the upper side of the positioning area onto the molded part stack, it moves outward on the lower side by a length equal to the thickness of the molded part, and once a complete stacked part is output on the lower side, it is separated and then used as a laminated core, while the upper side continues to be further filled.

[0036] In addition to using the processing fluid, heating can also be stopped (preferably temporarily when processing selected molded parts) in the area where the processing fluid is applied, i.e., the activation equipment can be stopped.

[0037] The application of processing fluid to the molded part occurs at least partially before step F), but preferably before step E). Otherwise, it preferably occurs after step C), and particularly preferably after step D), i.e., particularly preferably as an additional step between step D) and step E).

[0038] Preferably, the molding part is provided with the processing fluid on its entire surface on one side; alternatively, the molding part is provided with the processing fluid on both sides.

[0039] One variant presupposes that the molded part is equipped with the processing fluid on one side, that is, the side opposite the separation device. The advantage of doing so is that it avoids accidentally transferring the processing fluid to the next molded part through the separation device.

[0040] The predetermined quantity to be achieved should be understood as follows: multiple predetermined quantities can be predetermined, and reaching these predetermined quantities will cause a reduction in effectiveness, so that, before reaching the desired number of molded parts, the reduction in effectiveness may occur more than once according to one or more provisions. A molded part stack is then produced, having at least one rated break point, or, in the case of multiple predetermined quantities, multiple rated break points. At one or more rated break points, the molded part stack can be divided into two or more stack segments, which is preferably continuously achieved during the process. The number of rated break points the molded part stack has before separating the laminated core depends only on the height of the stack segments and the height of the positioning area.

[0041] The processing device is preferably arranged after the activation equipment, that is, arranged such that the molded part passes through the activation equipment first, and then the adhesive coating process is performed.

[0042] Alternatively, the processing device is arranged after the cutting equipment but before the activation equipment.

[0043] In other words: a stack of molded parts is formed within a positioning area up to a predetermined total height, wherein, upon reaching the total height, the stack serves as a core for laminations, i.e., it has a desired number of molded parts, including a certain number of rated break points or multiple rated break points. These rated break points are characterized in that the adhesion between two adjacent molded parts is lower than the adhesion between two adjacent molded parts outside the break point. Rated break points are formed as described above by reducing the effect of the adhesive, i.e., its potential adhesive force, after a predetermined number of molded parts. This process can be repeated multiple times during the formation of the stack of molded parts in the positioning area. For example, a stack of molded parts including a desired number N molded parts may have rated break points after every N / n molded parts, causing the effect of the adhesive coating to decrease each time at the N / nth molded part. As a result, the stack of molded parts has (n-1) rated break points and can be divided into n smaller stack segments. Here, N is an integer divisible by the integer n.

[0044] As in the example above, it can be preset that, until the desired number of molded parts is reached, all the subsequently predetermined number of molded parts have the same spacing, so that the desired number of molded parts form a laminated core with equidistantly distributed nominal break points, and then stacked body segments of the same height can be separated at the nominal break points.

[0045] Alternatively, it can be preset until a desired number of molded parts is reached, with the predetermined number of molded parts spaced apart as required, so that the desired number of molded parts form a laminated core with rated break points through which stacked body segments of different heights are separated from each other.

[0046] Individual stack segments are removed from the molded stack, wherein separation of the stack segments is achieved, for example, manually, at the adhesive coating where the effect of acting as a rated break point is reduced, based on the remaining adhesive force between the two stack segments. The individual stack segments are then reserved as finished laminated iron cores, for example, as finished stators, as finished rotors, or as sections of finished stators or rotors.

[0047] Special implementations featuring sheet metal sheets with full-surface bonding offer the advantage of integrated, sealed cooling channels. This is particularly advantageous when different or even incompatible cooling media are used in multiple electrical components (e.g., rotors and stators). The cooling channels can be stamped into the sheet or pre-installed between the laminated core and adjacent components (e.g., shafts or housings).

[0048] It should be noted that the stator, and if necessary, the rotor, can also be composed of multiple sections.

[0049] Therefore, step G) presupposes that one or more nominal fracture points are induced in the molded part stack filling the entire positioning area, wherein one or more nominal fracture points are generated by the molded part located at the nominal fracture point undergoing additional steps during steps C) to F). The additional step is that the molded part located at the nominal fracture point is at least partially (preferably the entire surface) equipped with a processing fluid to reduce the effectiveness of the adhesive coating on the molded part.

[0050] In one variant, the molded part coated with the treatment fluid may be equipped with the treatment fluid on only one surface. This surface then abuts against the rated fracture surface of the molded part.

[0051] In an alternative variant, the molded part coated with the treatment fluid may be equipped with the treatment fluid on both surfaces. The molded part is then abutted against two nominal fracture surfaces, serving as a discarded sheet that is not part of the stacked body segment.

[0052] The term "sheet metal" generally refers to rolled products made of metallic materials, and in addition to thin or thick sheets, it can specifically refer to metal strips, metal strips or sheets made of soft magnetic materials, steel strips, or electrical steel strips. Alternatively, other sheet metal manufacturing methods may be used.

[0053] Laminated cores are preferably either stator cores or rotor cores. In addition to the binder, laminated cores are also composed of so-called sheets, and therefore can also be called sheet cores.

[0054] According to an advantageous improvement of the method described at the beginning, the activation device includes a first infrared irradiation device. The adhesive coating is activated by infrared radiation and subsequently by heat input through the first infrared irradiation device.

[0055] In other words, a temperature sufficient for activation is provided in the sheet material and, in particular, in the adhesive, for example, by irradiation over a period of 0.05 to 1 second at the emission power required to reach the activation temperature, wherein the emission power, in its respective respects, depends on the exact choice of the adhesive and the properties of the molded part, particularly the properties of its surface and materials, and which can be determined without difficulty by those skilled in the art who are familiar with the implementation of the invention.

[0056] Particularly preferably, one or more activation devices are arranged between the cutting device and the separating device and include at least one upper infrared irradiation device pointing towards the surface of the first sheet in the stamping direction. Alternatively, the activation device includes at least one lower infrared irradiation device located opposite that side of the sheet, with the cutting device positioned on that side and the lower infrared irradiation device facing away from the stamping direction. Alternatively, either at least one upper infrared irradiation device or at least one lower infrared irradiation device can be pre-installed. It is not mandatory to achieve a right angle for the orientation of one or more infrared irradiation devices on the sheet surface; they can also be oriented at another angle.

[0057] In particular, when both an upper infrared irradiation device and a lower infrared irradiation device are present, when using a board with an adhesive coating on both sides, it is possible to activate the adhesive in a particularly suitable manner, both on the first board side and the opposite second board side. The advantageous result is that excellent adhesion between the boards can be expected.

[0058] According to one improvement, the activation device includes a second infrared irradiation device. The first and second infrared irradiation devices emit infrared radiation of different wavelengths to activate the adhesive coating at different activation depths. For example, the first infrared irradiation device can be pre-configured to have infrared radiation with wavelengths between 780 nm and 1200 nm, and / or the second infrared irradiation device can have infrared radiation with wavelengths between 1200 nm and 3000 nm. With this arrangement, a more uniform and particularly consistent activation of the adhesive coating can be provided due to the different penetration depths depending on the wavelength. This results in the advantage of particularly good adhesion and / or particularly good force absorption.

[0059] This arrangement can also be called dual activation. It can be implemented on one side or both sides.

[0060] Alternatively or additionally, the activation device may include an induction heater, which has the advantage of activating the adhesive from the adhesive-coated adhesion surface of the plate during induction heating, thereby achieving good activation and subsequent adhesion of the adhesive.

[0061] In one particular improvement, the material is preheated, for example, by induction heating, before entering the cutting equipment. The advantage of this is that activation within the press can be handled with lower heat, or the total heat introduced is increased and adhesion is improved, thereby meeting, for example, higher requirements in terms of mechanical properties.

[0062] Furthermore, the advantages of preheating include reduced clamping force, which is known to be beneficial, and lower forming power, resulting in lower residual stress. This effect can be achieved particularly well when additional optional adjustments are made to the cutting tool, as are familiar to those skilled in the art.

[0063] In another improvement, steps B) to E) are performed within the enclosure of the online facility, preferably all steps, to retain the introduced heat throughout the system as much as possible, which has the advantage of higher energy efficiency of the entire method.

[0064] Furthermore, facilities within the line, such as the strip inlet and repress station, can be actively heated, either partially or completely. For this purpose, the fuel heating commonly used for press frames and tool housings is extended to heating of tools, repress stations, and / or interior spaces, preferably counter-currently, for example, by means of a fan with a cylindrical heater.

[0065] In one particular embodiment, the activation temperature in the in-line facility can be preset to be between 30°C and 180°C, preferably between 40°C and 120°C, particularly preferably between 50°C and 100°C, and repressurization is performed in the repressurization station at a temperature higher than the activation temperature. Various variations are preset in the improved embodiments, according to which the processing apparatus includes a coating unit for treating the adhesive coating, by which a processing fluid is applied to the molded parts, at least in sections, onto the adhesive coating. The processing fluid is used to reduce the effect of the adhesive in selected molded parts after a predetermined number of molded parts have been reached, such that the resulting stack of molded parts has a nominal break point at that location, separating two overlapping stack sections from each other. The coating unit can be, for example, a coating roller or a roller unit consisting of two opposing coating rollers, parallel or perpendicular to the transport direction of the molded parts in the in-line facility, traveling over the selected molded parts to coat them.

[0066] It can be preset that the selected molded part is equipped with processing fluid on one or both sides. If the molded part is coated with processing fluid on both sides, the molded part can be separated from the stack body section on both sides and then removed as waste without any further function.

[0067] Preferably, the entire surface of the molded part is coated with the processing fluid.

[0068] Preferably, the stamping oil is applied to the adhesive coating as a processing fluid, which has the advantages of easy availability and additional suitability because the stamping oil is inevitably used in the process anyway, so that no undesirable reaction will occur due to the use of another kind of substance.

[0069] Preferably, the stamping oil is a self-volatile stamping oil.

[0070] As a stamping oil, for example, a non-water-soluble cooling lubricant can be considered, especially a medium-viscosity metalworking oil for non-chip forming.

[0071] Preferably, an oil free of chlorine and heavy metals such as barium is used, which is suitable for deep drawing operations and ensures a homogeneous lubricating film through its adhesion and wetting properties. More preferably, the oil has a viscosity of 80 to 110 mm² / s, preferably 90 to 100 mm² / s, at 40°C, and a flash point of >150°C, preferably >170°C. In particular, the oil contains phenol and isopropyl-substituted phosphate esters, preferably in a 3:1 ratio, and optionally includes triphenyl phosphate in a 5% by weight proportion.

[0072] For example, oils such as those sold by Castrol under the trademark Iloform FST 16 at the filing date of this application may be used.

[0073] Alternatively or additionally, an irradiation device can be used as a treatment for the adhesive coating to make the adhesive coating photosensitive. For example, the infrared irradiation device used for activation can be used for photosensitive over-exposure by, for example, temporarily increasing the irradiation power of the infrared irradiation device in the selected molded part and / or by temporarily slowing down or temporarily stopping the transport of the molded part, thus increasing the residence time of the molded part under the infrared irradiation device.

[0074] Alternatively or additionally, a humidification unit can be used to apply a coolant, such as liquid nitrogen, to the adhesive coating as a treatment of the adhesive coating.

[0075] According to the invention, in step F), the molded part is placed. Furthermore, preferably, after each placement of the molded part, or after placing a specific, predetermined number of molded parts, or after forming a stack of molded parts, the molded part is pressed with an axial force—that is, a force perpendicular to the flat surface—for example, by means of a clamping punch. The axial force supports the force generated by the weight of the molded part itself, but is significantly lower than the force applied during possible re-pressing.

[0076] Particularly preferably, after separating the stacked sections, the stacked sections are re-pressed in a press, wherein the pressure on the end face, i.e., the pressure perpendicular to the sheet surface and preferably constant on the end face, is 10000 N / (14000 mm²). 2 ) to 200000N / (10000mm 2The temperature of the molded part stack is preferably between 50,000 N / (14,000 mm²) and 150,000 N / (10,000 mm²), and the temperature of the molded part stack is between 30°C and 180°C, preferably between 40°C and 120°C, and particularly preferably between 50°C and 100°C. Thus, compression is performed in a two-stage process, where the first stage is forming the molded part stack of step F) or a segment of the stack formed by the molded part stack of step F), and the second stage is recompression. It has been shown that the two-stage compression results in a significant improvement in adhesion, approximately doubling the force required to separate the stack segments during a head tensile test (Kopfzugprüfung). Exemplary measurements will be described below. Other proven advantages include improved heat dissipation and an increase in shear strength of more than 5% for the entire composite.

[0077] The precise matching of temperature and pressure is performed by those skilled in the art, taking into account cycle time and economic factors. This precise matching may also depend on the ratio of adhesive thickness to sheet thickness, but the configuration of the selected activation equipment is also particularly dependent on the requirements of the component to be created.

[0078] Heating of the molded part stack is achieved in the positioning device by means of an irradiation device that generates heat input, which is arranged in or beside the separation device if necessary, and / or by means of an induction device arranged on the positioning device, and the residual heat obtained from the heating in the area mentioned above is utilized during the repressing process. Preferably, the temperature of the molded part stack is between 30 degrees Celsius and 180 degrees Celsius, preferably between 40 degrees Celsius and 120 degrees Celsius, and particularly preferably between 50 degrees Celsius and 100 degrees Celsius.

[0079] The compression step is performed by pressing the laminated core in the axial direction on the end face side with uniform planar pressure, i.e., in the direction perpendicular to the surface of the laminations. This pressing process achieves particularly good fabrication of an adhesive composite between individual molded parts, thereby contributing to the durability of the laminated core. Preferably, the downstream compression step is performed in a downstream compression station, outside the press.

[0080] In one improved design, compression can be achieved through path adjustment rather than force adjustment. This is achieved, for example, through an adjustable stop. Combined with very precise temperature control, the axial length of the component can be set very precisely.

[0081] However, alternatively, the compression step can be achieved by applying pressure to a preferred portion or the entire surface of the separation device.

[0082] The exceptionally good mechanical strength of laminated iron cores achieved through bonding and repressing is particularly advantageous, thereby allowing for significantly simpler and more precise machining processes. Consequently, it is easier to meet requirements that increase with rotational or circumferential speeds. Other advantages include a high degree of structural freedom.

[0083] Because the individual sheets (or “sandwiches”) are heated more uniformly, more homogeneous heating is achieved, accompanied by advantages such as better geometry and lower internal stress.

[0084] Particularly preferably, the method is performed on a sheet material, wherein the adhesive coating is applied to the sheet material as an aqueous dispersion. The advantage of an aqueous dispersion is that the coating system is free of organic solvents (VOCs).

[0085] Furthermore, the advantage lies in the fact that the coated sheet is dried to near non-stickiness, making it possible to wind it into coils without causing individual turns to stick together. Additionally, this results in subsequent chemical cross-linking under pressure and temperature. Solvent-containing, dissolved epoxy resin systems are generally not sufficiently high in molecular weight for non-stick drying, and their disadvantage is that, if present, it is very difficult to unwind individual turns in the coil, thus hindering their use in subsequent processes.

[0086] Therefore, one embodiment presupposes, in a particularly preferred manner, that the applied adhesive coating is not present in a state dissolved in an organic solvent.

[0087] The adhesive coating preferably consists of an adhesive that, compared to commercially available baking paint systems known to those skilled in the art, exhibits significantly higher viscosity, particularly significantly higher complex viscosity, under comparable firing conditions just before the onset of chemical crosslinking, as illustrated by the test results shown below. This results in the advantage that the adhesive does not liquefy at the temperatures achieved during the process of the method or its modifications according to the invention; rather, the adhesive remains malleable, i.e., softened, allowing it to remain completely within the molded part stack.

[0088] In particular, it is preferable to use an adhesive that is not a hot melt adhesive, i.e., preferably an adhesive that is not liquid at the activation temperature of up to 180 degrees Celsius described above.

[0089] Particularly preferably, the adhesive used has a complex viscosity of 8 Pa x s or higher, preferably 10 Pa x s or higher, in the "complex viscosity (temperature)" curve just before the onset of chemical crosslinking, for example, at a local minimum in the temperature range immediately adjacent to chemical crosslinking. In the method according to the invention or its modifications, an adhesive with a complex viscosity not lower than the aforementioned level at temperatures below the onset of chemical crosslinking will not induce large-area liquefaction of the adhesive, but in any case, at the temperature used, particularly even at the activation temperature used, the adhesive remains in a paste-like state. This, in turn, results in a laminated core with excellent properties, particularly high dimensional stability in geometry. Such a laminated core is also particularly suitable for implementing methods with a re-pressing step, thereby further contributing to high dimensional stability in geometry.

[0090] The adhesive preferably comprises:

[0091] 60 parts by weight of epoxy resin in solid resin form.

[0092] 0.5 to 15 parts by weight of latent curing agent,

[0093] 1 to 15 parts by weight of a latent accelerator.

[0094] Preferably, the adhesive contains 1 to 10 parts by weight of a latent curing agent, particularly preferably 2 to 5 parts by weight of a latent curing agent.

[0095] The term "latent curing agent" refers to a substance used for curing epoxy resins, but which must be specifically activated by supplying chemical and / or thermal energy for curing. Latent curing agents are added to adhesives, for example, as solid substances existing in powder form.

[0096] The term "latent accelerator" refers to a substance that accelerates the curing of epoxy resins achieved by a latent curing agent. Regarding accelerators, the qualifier "latent" also means that the accelerator must be activated beforehand by chemical and / or thermal energy to perform its function. Latent accelerators are added to adhesives, for example, as solid substances existing in powder form.

[0097] The composition given above refers to a mixture of components existing as solids in a given amount of weight that constitute an adhesive mixture, which, in a dispersion and / or solution, becomes an adhesive capable of forming an adhesive coating by means of a suitable liquid. The adhesive comprising the given components, in a usable state, i.e., in a form suitable for coating, preferably exists as a dispersion of the composition given above in a dispersion medium, particularly as an aqueous dispersion.

[0098] Because the provided sheet material includes an adhesive coating made of a heat-activated adhesive, the adhesive-coated sheet material serves as a semi-finished product for a manufacturing method that can be flexibly adjusted for electromagnetic components (particularly stator or rotor cores). Since the adhesive must first be heat-activated, the bonding function can be performed at a desired time point or in a desired process step, for example, after the sheets are removed from the sheet material by stamping. Within a short period after activation, the sheets must be assembled (optionally, preferably also in a press and / or under partial or full surface pressure in a downstream compression process) so that they bond together during the chemical hardening reaction. Only in this way can a defect-free, non-delaminated, geometrically precise, and mechanically stable core be produced.

[0099] The adhesive composition described herein provides a potentially short activation time for the surface of the sheet, for example, from 0.05 to 1 second, preferably from 0.3 to 1 second. These properties are accompanied by relatively high heat resistance and relatively high insulation and aging resistance.

[0100] The epoxy resin present in the described adhesive comprises one or more epoxy resin components, which include more than one epoxy group, wherein preferably, at least one epoxy resin has a softening point above 50 degrees Celsius.

[0101] Epoxy resins can be aliphatic, alicyclic, or aromatic epoxy resins. Aliphatic epoxy resins contain components carrying aliphatic groups and at least two epoxy resin groups.

[0102] Examples of aliphatic epoxy resins include butanediol diglycidyl ether, hexanediol diglycidyl ether, diepoxydimethylpentane, diepoxybutane, and diethylene glycol diglycidyl ether.

[0103] Alicyclic epoxy resins include, for example, 3-cyclohexenylmethyl-3-diepoxycyclohexylcarboxylate, 3,4-epoxycyclohexylalkyl-3',4'-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxyo-methylcyclohexanecarboxylate, diepoxyvinylcyclohexane, di(3,4-epoxycyclohexylmethyl)adipate, diepoxydicyclopentadiene, and 1,2-epoxy-6-(2,3-epoxypropoxy)hexahydro-4,7-bridged methylene indene.

[0104] Aromatic epoxy resins include, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol-phenolic epoxy resin, cresol-phenolic epoxy resin, biphenyl epoxy resin, bisphenol epoxy resin, 4,4'-biphenyl epoxy resin, diepoxydivinylbenzene, 2-glycidylphenylglycidyl ether, and tetraglycidylmethylenebisphenylamine.

[0105] In a preferred design, the epoxy resin is a bisphenol A epoxy resin.

[0106] As a latent curing agent, a substance or a mixture of such substances is used that preferably cures with the epoxy resin of the adhesive at a temperature in the range of 80 degrees Celsius to 200 degrees Celsius.

[0107] The curing agent may contain aziridine derivatives, triazine derivatives, imidazolines, imidazoles, o-toluidine, cyclic amidines, organohexafluoroantimonate compounds, hexafluorophosphate compounds, or BF3-amine complexes. These compounds may be used alone or in combination.

[0108] Examples include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole-onium trimellitate, 1-cyanoethyl-2-phenylimidazole-onium trimellitate, and 2,4-diamino-6-[2'-methylimidazole-(1'-methylimidazole-onium)-(2 ... )]-Ethyltriazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyltriazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-meta-2,4-diamino-6-[2”-methylimidazolyl-(1')]-ethyltriazine, 2-phenylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, (1-dodecyl-2-methyl-3-benzyl)imidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, 2 4-Diamino-6-vinyl-1,3,5-triazine, 2,4-diamino-6-vinyl-1,3,5-triazine isocyanate adduct, 2,4-diamino-6-methacryloyloxyethyl-1,3,5-triazine, 2,4-diamino-6-methacryloyloxyethyl-1,3,5-triazine isocyanate adduct, 1,3,5-triazine, 2,4-diamino-6-methyl-1,3,5-triazine, 2,4-diamino-6-nonyl-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-dimethoxy-6-methyl-1,3,5-triazine, 2,4-dimethoxy 6-Phenylacetyl-1,3,5-triazine, 2-Amino-4,6-dimethyl-1,3,5-triazine, 2-Amino-4-dimethylamino-6-methyl-1,3,5-triazine, 2-Amino-4-ethoxy-6-methyl-1,3,5-triazine, 2-Amino-4-ethyl-6-methoxy-1,3,5-triazine, 2-Amino-4-methoxy-6-methyl-1,3,5-triazine, 2-Amino-4-methyl-6-phenyl-1,3,5-triazine, 2-Chloro-4,6-dimethoxy-1,3,5-triazine, 2-Ethylamino-4-methoxy-6-methyl-1,3,5-triazine, 1-o-tolyl biguanide.

[0109] In a preferred design, the accelerator comprises a urea derivative and / or imidazole.

[0110] In addition, the adhesive composition may also contain other components, such as preservative additives.

[0111] Preferably, the curing agent comprises dicyandiamide, imidazole, BF3-amine complex, or a combination thereof.

[0112] In one design, the adhesive may contain 1 to 10 parts by weight of a latent accelerator, preferably 1 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight of a latent accelerator.

[0113] In another preferred embodiment, the adhesive is further provided with 0.2 to 8 parts by weight, preferably 0.2 to 4 parts by weight, of pigment. The optical appearance of the surface can thus be configured to be more pleasing. The pigment may be selected from the group consisting of flame black, iron black coatings, or water-soluble pigments, or mixtures thereof.

[0114] Preferably, the adhesive contains one or more insulating additives known to those skilled in the art, wherein the term "insulating additive" refers to an additive specifically provided to improve the resistance of the adhesive. The insulating additive can be included in the adhesive in an amount of 1 to 10 parts by weight, preferably 1 to 5 parts by weight.

[0115] Preferably, the adhesive contains one or more preservative additives known to those skilled in the art. The preservative additives can be included in the adhesive in an amount of 1 to 10 parts by weight, preferably 1 to 5 parts by weight.

[0116] In one variant of this method, the latent accelerator comprises a urea derivative.

[0117] The latent accelerator contained in the adhesive preferably consists of at least 50 wt.%, more preferably at least 90 wt.%, of a urea derivative, and even more preferably consists entirely of it.

[0118] As a urea derivative, N,N-dimethylurea or N,N'-dimethylurea or a bifunctional urea derivative comprising two urea groups as functional groups is preferably used. Specifically, 4,4'-methylenebis(phenyldimethylurea) or a mixture thereof is particularly preferred.

[0119] The latent accelerator contained in the adhesive preferably consists of at least 50 wt.%, more preferably at least 90 wt.%, more preferably at least 98 wt.%, of 4,4'-methylenebis(phenyl dimethylurea), and particularly preferably consists entirely of it.

[0120] In a variant of this method, urea with asymmetric substitution is used, or only used, as a urea derivative.

[0121] In an alternative improvement to this method, a urea derivative is used, wherein at least one, preferably two, particularly preferably three hydrogen atoms are independently replaced by alkyl groups and / or phenyl groups that can be substituted in each respect. Preferably, the alkyl group is methyl, ethyl, propyl, or butyl, preferably methyl; the phenyl group is phenyl or preferably one of the above-mentioned alkyl groups that is poorly substituted at position 4, also preferably one of the above-mentioned alkyl groups. In another alternative, for the purposes of this invention, the bifunctional urea derivative, as the derivative described above, comprises two functional groups. A functional group is an atomic group that decisively determines the properties of a substance and, particularly, the reactive behavior of the compound, especially the functional group undergoes a reaction. Further, the urea derivative to be used is halogen-free. In one alternative, the urea derivative to be used comprises two urea derivatives as functional groups. Advantageously, this allows the epoxy resin to be cured without the presence of dicyandiamide as a crosslinking agent.

[0122] As a urea derivative, a substance can also be pre-defined.

[0123]

[0124] Where R is hydrogen or according to

[0125] The groups, in which

[0126] n = 0 or 1, preferably 1.

[0127] X = O or S, preferably O.

[0128] R1, R2, and R3 are hydrogen, halogen, nitro, substituted or unsubstituted alkyl, alkoxy, aromatic, or aryloxy groups, respectively.

[0129] R4 is an alkyl, alkenyl, cycloalkyl, cycloalkenyl, or optionally substituted with a halogen, hydroxyl, or cyano group, preferably methyl, ethyl, propyl, or butyl, with methyl being particularly preferred; R5 is such as R4 or an alkoxy group, and R5 may optionally form a heterocycle with R4.

[0130] Or N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, or N,N-dimethyl-N'-(3-chloro-4-methyl-phenyl)urea, or N,N-dimethyl-N'-(3-chloro-4-methoxyphenyl)urea, or N,N-dimethyl-N'(3-chloro-4-ethylphenyl)urea, or N,N-dimethyl-N'-(4-methyl-3-nitrophenyl)urea, or N-(N'-3,4-dichlorophenylcarbamoyl)morpholine, or N,N-dimethyl-N'(3-chloro-4-methylphenyl)thiourea;

[0131] Preferably, the urea derivative is 4,4'-methylenebis(phenyldimethylurea);

[0132] Or a mixture of two, three or more of the aforementioned. Such a mixture preferably contains at least 10%, 25%, more preferably 50%, 60%, 70%, 80% or 90% of 4,4'-methylenebis(phenyldimethylurea).

[0133] The advantages of the aforementioned urea derivatives are derived from GB 1293142 A. The inventors have discovered that these derivatives can be used excellently in the manufacture of electromagnetic components.

[0134] The average particle size (arithmetic mean) of the urea derivative is preferably between 1 micrometer and 30 micrometers.

[0135] It can be preset that the adhesive coating is applied to the board on one side or both sides. If the adhesive coating is applied to both sides, the coating thickness can be the same, but different thicknesses can also be preset.

[0136] The preferred adhesive coating thickness, i.e., the coating thickness on one side when applying a single-sided adhesive, or the total thickness of the adhesive coatings on both sides when applying a double-sided adhesive, is between 1 micrometer and 20 micrometers, preferably between 2 micrometers and 10 micrometers. Particularly preferably, the total thickness is between 4 and 8 micrometers.

[0137] Single-sided adhesive coating of sheet metal is accompanied by simpler manufacturing of the instrument, while double-sided adhesive coating of sheet metal has the advantage that the adhesive surface is positioned on the adhesive surface during the mutual positioning of individual sheets made from the sheet metal, thereby achieving improved adhesion and thus higher mechanical stability of electromagnetic components, as has been demonstrated in experiments.

[0138] Particularly preferably, the first sub-coating on the surface of the first substrate and the second sub-coating on the surface of the second substrate of a second thickness are adapted to each other such that the first thickness is at least 1.5 times, preferably twice, the second thickness. In this configuration, the first thickness ensures excellent insulation, virtually eliminating the risk of adhesive gaps, while the thinner coating, i.e., the second sub-coating applied at the second thickness, is primarily used to produce excellent adhesion.

[0139] Double-sided coating with a total thickness of 4 to 6 micrometers is particularly preferred. This low coating thickness is possible due to the high reactivity of the method performed according to the invention or its modifications, as demonstrated by the resulting examples. Known baking varnish adhesives typically require coating thicknesses greater than 6 micrometers (e.g., 5 μm per side for double-sided baking varnish). This results in the advantage that, based on experiments conducted according to the invention, stators or rotors with a significantly higher iron-filling coefficient than components manufactured by baking varnish can be specifically manufactured from one of the types of sheet metal described. The advantage is higher efficiency in motors incorporating this component. However, a total adhesive coating thickness between 1 and 20 micrometers, preferably between 2 and 8 micrometers, can be pre-set.

[0140] In another alternative, a pretreatment, adhesion enhancer, phosphating treatment, and / or an insulator designed as an insulating varnish layer are arranged between the board and the adhesive layer, and / or only an insulating varnish is arranged on the side of the board opposite to the adhesive layer, or an uncoated surface.

[0141] Particularly preferred, the sheet is designed as a non-grain-oriented electrical steel strip, also known as so-called NO-electrical steel strip, or separated from such electrical steel strip, wherein, in addition to Fe and unavoidable impurities, the non-grain-oriented electrical steel strip also contains the following elements (all data are in wt.%):

[0142] Si from 0.1 to 3.50

[0143] Al from 0.01 to 1.60,

[0144] Mn from 0.07 to 0.65

[0145] Optionally, P up to 0.25.

[0146] It should be understood that the sum of all alloy components and impurities is complementary to 100 wt.%.

[0147] Particularly preferably, the conditions described below are met (all data are in wt.%):

[0148] Si from 2.3 to 3.40

[0149] Al from 0.3 to 1.1

[0150] Mn from 0.07 to 0.250

[0151] Optionally, up to 0.030 P, with the remainder being Fe and unavoidable impurities.

[0152] It should be understood that the sum of all alloy components and impurities is complementary to 100 wt.%.

[0153] Preferably, the non-grain-oriented electrical steel strip or non-grain-oriented sheet has, according to DIN EN ISO 6892-1, a yield strength of 190 to 610 MPa, a maximum tensile strength of 310 to 740 MPa, a minimum elongation at break of 6 to 48% (A80), and a hardness of 100 to 250 (Hv5) in the longitudinal direction under standard conditions.

[0154] In a particularly preferred embodiment, the raw material, measured according to DIN EN ISO 6892-1, has a yield strength of 310 to 600 MPa in the longitudinal direction, a maximum tensile strength of 400 to 640 MPa, an A80 elongation at break of 7 to 32%, and an Hv5 hardness of 130 to 250 at room temperature.

[0155] Preferably, the material has anisotropy in the range of 5% to 17% at P1.0 / 400Hz.

[0156] Suitable and preferred, sheet metal with a thickness between 0.05 and 2.5 mm is used, particularly electrical steel strip, with a thickness preferably between 0.1 and 1.0 mm. Particularly preferred is a thickness between 0.15 and 0.4 mm.

[0157] Alternatively, the sheet material can be a multilayer composite (sandwich structure) consisting of sheet layers (e.g., one of the electrical steel strips described above) and one or more additional layers, such as an acoustic damping functional layer (e.g., bondal E). Furthermore, the sheet material can also be coated with an acoustic damping functional layer (e.g., Halb-bondal E) on one or both sides, allowing the described adhesive system to be directly bonded to the acoustic damping functional layer (e.g., a chemically based acrylate). According to the art, epoxy resin systems are known to have good compatibility.

[0158] Alternatively, the sheet material may have an acoustic damping layer on one side and an adhesive layer to be used on the opposite side of the sheet material.

[0159] In an advantageous improvement, steps C) to F) of the method according to the invention are performed with a stroke count of at least 80 strokes per minute, preferably between 120 and 300 strokes per minute. Significantly higher stroke counts than 300 strokes per minute can also be achieved when the requirements for adhesive bonding are lower or the electrical components are smaller.

[0160] The present invention relates to a laminated iron core or a stacked section of a laminated iron core for an electric motor, which is manufactured by a method of the type described at the beginning or a modification thereof. In particular, the laminated iron core or the stacked section is designed as a stator or a rotor.

[0161] Furthermore, the present invention includes an electric motor, particularly an electric motor, comprising a stator and / or rotor manufactured by a method or an improvement thereof according to the invention.

[0162] In one improved embodiment, the motor includes a stator and a rotor, wherein the stator is partially or entirely a laminated iron core manufactured according to the method or an improvement thereof, and the rotor is partially or entirely a structural element manufactured by means of specialized stamping and lamination. This provides a stator with excellent electromagnetic characteristics, meeting particularly high-quality requirements in terms of electromagnetic performance, but a rotor with lower quality requirements in terms of electromagnetic characteristics in a variety of applications, manufactured through very cost-effective conventional stamping and lamination. Therefore, a motor is provided that offers a particularly good trade-off between providing good electromagnetic characteristics and cost-effective manufacturing. Attached Figure Description

[0163] Further details, features, and advantages of the subject matter of this invention will be apparent from the following description with reference to the accompanying drawings, in which embodiments of the invention are illustrated by way of example.

[0164] Figure 1 An example of a first embodiment of a method suitable for manufacturing laminated iron cores for electric motors is shown.

[0165] Figure 2a and Figure 2b The test results are shown.

[0166] Figure 3 The complex viscosity of a sample including an adhesive such as sample 3 is shown, as well as the complex viscosity of a sample including a conventional paint. Detailed Implementation

[0167] It should be understood that the features mentioned above and described below can be used not only in the combinations given separately, but also in other combinations or individually. Examples

[0168] An example of a first embodiment of a method suitable for manufacturing laminated iron cores for electric motors is shown. Figure 1The process involves providing a sheet material already coated with adhesive, more specifically, in the form of an amorphous oriented electrical steel strip 1 coated with an adhesive of a type predetermined according to the invention. This steel strip is transported into the in-line facility. At a first station, a number of cutting devices 4, designed as dies, are responsible for cutting molded parts 2 designed as rotor or stator laminations. At the next station, the molded parts are irradiated by means of a device 5 designed as an NIR emitter for emitting infrared radiation, thereby activating the adhesive coating of the molded parts through the resulting heating. The activation device 5 includes a first infrared irradiation device 5a and a second infrared irradiation device 5b. The first irradiation device 5a emits radiation with wavelengths from 780 nm to 1200 nm, while the second irradiation device emits radiation with wavelengths from 1200 nm to 3000 nm. By irradiating with different wavelengths, more uniform activation of the adhesive coating is achieved in a direction perpendicular to the sheet surface, and furthermore, due to higher efficiency, an increased number of passes is allowed because a shorter duration is required to activate the adhesive coating.

[0169] A specific sheet is coated using a processing device 9 designed as a coating roller to serve as a nominal break point between individual lamination cores in a subsequent molded part stack. The coating roller 9 always travels to the sheet material (in the figure shown, entering the paper plane) after a predetermined number of molded parts have been reached, and coats the subsequent molded parts immediately after reaching the predetermined number, to reduce or completely eliminate the effect of the adhesive coating. The coated molded parts then have a nominal break point at which the molded part stack can preferably be separated into stack segments during the continuous process, and each of these stack segments presents a finished lamination core. During the manufacture of the molded part stack, the sheet 8 corresponds to the predetermined number of molded parts reached. For this reason, it is coated with stamping oil using the coating roller 9, which is configured as a processing device, and thus has reduced adhesive strength.

[0170] Subsequently, the molded parts are extruded using a separation device 6 designed as a die, and in the positioning area, they are collected into a stack 3 with positional alignment and / or corner alignment and pre-fixed, i.e., the sheets equipped with activated adhesive coatings have adhered to each other due to their own weight.

[0171] In the removed state, the laminated core is a segment of the molded stack removed at the nominal break point 8, which has a less effective adhesive coating at the sheet 8. The stacked core segment can be removed by its own weight, or separated from the molded stack by instrument support or manual support. In the current example, there are two separate stacked core segments, which are recompressed in the compressor station 7 as stacked core segment 3' in a subsequent step.

[0172] Finally, in the compression station, compression is achieved using the compressor punch 7 until the adhesive hardens and the finished laminated iron core can be removed.

[0173] The embodiments for the advantageously usable sheet metal and their advantageous performance in the method according to the invention are derived from the tests conducted.

[0174] The following samples were manufactured:

[0175] The slab is from electrical steel strip M800-50A (according to EN 10027-1), with a material designation (Werkstoffkennzahl) of 1.0816 (according to EN 10027-2), a thickness of 0.5 mm, and a length × width of 200 × 150 mm.

[0176] Samples 0, 1, 2, and 3 were manufactured. Samples 0, 1, and 2 were control samples, coated with an adhesive that was not advantageous.

[0177] Sample 3 is a favorable sample.

[0178] The manufactured sample is a slab of the type described above, which is coated with adhesive by a coating roller according to the following parameters:

[0179]

[0180] Layer thickness

[0181] Sample 0: First surface: 6 μm, Second surface: 0 μm

[0182] Sample 1: First surface: 6 μm, Second surface: 0 μm

[0183] Sample 2: First surface: 4 μm, Second surface: 2 μm

[0184] Sample 3: First surface: 4μm, Second surface: 2μm.

[0185] Multiple samples were fabricated for each sample type. To test long-term stability, 18 sandwich structures were fabricated in pairs for the same sample.

[0186] Each time a plate is passed through the plate press, a 200mm x 200mm plate is pressed at a rate of 3N / mm. 2 Two samples of the same type were bonded using surface pressure bonding, with the adhesive activated in an oven by heating to 120°C and maintaining that temperature for 30 minutes. Subsequently, eight samples were placed in the oven and stored at 40°C. One sample was removed each week and subjected to a shear value test (according to DIN EN 1465). In addition, a shear value test was performed weekly on samples stored at room temperature. The test results were displayed...Figure 2a and Figure 2b middle.

[0187] The results show that, at room temperature, the advantageously used composition exhibits superior shear values ​​compared to the reference samples, namely Sample 0, Sample 1, and Sample 2. Sample 0, tested after six weeks, showed a significantly reduced shear value, and after eight weeks, its shear value was 0.

[0188] In reference sample 0, storage at 40°C resulted in a shear value of 0 after at least one week, indicating that this sample exhibits no storage stability at 40°C. After two weeks, samples 1 and 2 showed almost no change in shear strength above 7.0 N / mm². 2 It has good shear values, but begins to degrade significantly after three weeks of storage.

[0189] In all cases, the shear value of sample 2, including the double-coated surface, was higher than that of sample 1, including the single-coated surface. This is evidence of the particularly advantageous effect of the double-coated panels.

[0190] In particular, it can be seen that Sample 3 exhibits the best storage stability, with its good shear value remaining almost unchanged after 4 weeks of storage at 40 degrees Celsius. As the sole sample, a slab sandwich structure was obtained, which also showed a good shear value that remained unchanged after four weeks of storage at 40 degrees Celsius. These experiments are still ongoing as of the application date.

[0191] In addition, tests were conducted on the completed sandwich structures, which were heated to the test temperature and then held for a short time before being subjected to shear tests under heat.

[0192]

[0193] The results show that both Sample 2 and Sample 3 can withstand temperatures up to 200 degrees Celsius for a certain period without losing their mechanical stability. However, it is particularly evident that the shear value of Sample 3 is significantly higher than that of the corresponding value of the control Sample 2, while its dispersion is significantly lower.

[0194] For reference, sample 0 underwent temperature testing, which showed that after heating to 150 degrees Celsius, approximately 0.90 N / mm² was obtained. 2 The shear value. Thus, based on sample 3, it is shown that, compared to known plates, the advantageous plate is suitable for manufacturing laminated cores with higher temperature stability.

[0195] exist Figure 3As demonstrated by the experiments conducted, even at temperatures around 100 degrees Celsius, advantageous adhesives, including those used in Sample 3, exhibit significantly higher complex viscosities than commercially available paints. Specifically, prior to the commencement of chemical cross-linking, the complex viscosity, at 10.74 Pa x s, is significantly higher than that achieved by conventional paints. This enables the advantageous use of sheets coated with this adhesive in the method according to the invention, and particularly in its modified repressurization scheme, as liquefaction of the adhesive does not occur, and a transition to a paste-like property is achieved in all cases. Consequently, no notable flow of adhesive from the laminated core is observed, with the corresponding advantage being particularly good adhesion, which can be demonstrated, for example, by tensile testing.

[0196] Other tests, not shown, concluded in a long-term test lasting 70 days that: Sample 3 was of comparable quality to each of Samples 0 to 2 in terms of oil resistance, i.e., in the shear value test, after being stored in oil at 150 degrees Celsius for 70 days, no decrease in the adhesion between the sheets was found.

Claims

1. A method for manufacturing laminated iron cores for electric motors, characterized in that, The method includes the following steps: Step A) Provide one or more sheets equipped with a polymer-based adhesive coating that can at least partially cure; Step B) Transport the sheet material to an in-line facility, the in-line facility comprising: at least one cutting device, a separating device, and an activation device for activating the adhesive coating; Step C) Using at least one of the cutting devices, cut the molded part from the sheet metal provided in step A); Step D) Activate the adhesive coating of the molded part by means of the activation device for activating the adhesive coating of the molded part; Step E) Using the separation device, separate the molded part from the sheet metal; Step F) Place the molded part into the positioning area to form a stack of molded parts; Step G) Repeat steps C) to F) to continuously fill the positioning area with molded parts, wherein after a predetermined number of molded parts are reached, for subsequent molded parts, before performing step F), by means of a processing device, at least a partial area of ​​the subsequent molded parts are supplied with processing fluid to reduce the effect of the adhesive coating on the subsequent molded parts, such that due to the reduced effect of the adhesive coating, in the positioning area, the adhesive coating of the subsequent molded parts causes the stacked body segments located below the reduced adhesive coating to better separate from the stacked body segments located above the reduced adhesive coating. After the stacked sections are separated, they are repressed in a press, with the pressure on the end face, i.e. the pressure perpendicular to the sheet surface, ranging from 10,000 N / (14,000 mm²) to 200,000 N / (10,000 mm²).

2. The method according to claim 1, wherein the laminated iron core for the motor is a stator core or a rotor core.

3. The method of claim 1, wherein the activation device is arranged between at least one of the cutting devices and the separating device.

4. The method of claim 1, wherein the molded part is designed as a stator sheet or as a rotor sheet.

5. The method according to claim 1, wherein in step D), the adhesive coating of the molded part formed in step C) is activated by means of the activation device for activating the adhesive coating of the molded part.

6. The method according to any one of claims 1 to 5, wherein the activation device comprises a first infrared irradiation device, and the adhesive coating is irradiated with infrared radiation and thereby activated.

7. The method of claim 6, wherein the activation device includes a second infrared irradiation device, wherein the first infrared irradiation device and the second infrared irradiation device emit infrared radiation of different wavelengths to activate the adhesive coating at different activation depths.

8. The method of claim 7, wherein the first infrared irradiation device emits wavelengths between 780 nm and 1200 nm, and the second infrared irradiation device emits wavelengths between 1200 nm and 3000 nm.

9. The method according to any one of claims 1 to 5, wherein the activation device comprises an induction heater.

10. The method according to any one of claims 1 to 5, wherein - The processing fluid is a separated liquid and the processing device is a coating unit, through which the separated liquid is applied to the adhesive coating as a treatment of the adhesive coating; or - The processing fluid is a cooling fluid and the processing device is a humidification unit. As a treatment of the adhesive coating, the cooling fluid is applied to the adhesive coating through the humidification unit.

11. The method of claim 10, wherein the cooling fluid is designed as a coolant.

12. The method of claim 10, wherein the processing fluid is a separation liquid designed as stamping oil.

13. The method of claim 1, wherein the pressure on the end face side is between 50,000 N / (14,000 mm²) and 150,000 N / (10,000 mm²).

14. The method of claim 1, wherein the temperature is between 30 degrees Celsius and 180 degrees Celsius.

15. The method of claim 14, wherein the temperature is between 40 degrees Celsius and 120 degrees Celsius.

16. The method of claim 15, wherein the temperature is between 50 degrees Celsius and 100 degrees Celsius.

17. The method of claim 1, wherein the pressure on the end face side is uniformly distributed on the end face.

18. The method of claim 1, wherein the adhesive coating is applied to the plate as an aqueous dispersion; and / or The adhesive coating has a complex viscosity, which is at least 8 Pa·s before chemical crosslinking begins.

19. The method of claim 18, wherein the viscosity is 10 Pa·s just before chemical crosslinking begins.

20. The method of claim 1, wherein the adhesive coating comprises: 60 parts by weight of epoxy resin in solid resin form. 0.5 to 15 parts by weight of latent curing agent, 1 to 15 parts by weight of a latent accelerator.

21. The method according to any one of claims 1 to 5 and 18 to 20, wherein the sheet material provided in step A) is provided with the adhesive coating on both sides.

22. The method of claim 20, wherein the latent accelerator comprises a urea derivative, or the latent accelerator comprises a mixture of multiple urea derivatives.

23. The method of claim 22, wherein the latent accelerator further comprises or only comprises an asymmetrically substituted urea.

24. The method of claim 22, wherein the latent accelerator comprises N,N-dimethylurea or N,N'-dimethylurea.

25. The method of claim 22, wherein the latent accelerator comprises a bifunctional urea derivative comprising two urea groups as functional groups.

26. The method of claim 22, wherein the latent accelerator comprises 4,4'-methylenebis(phenyldimethylurea).

27. The method of claim 22, wherein the urea derivative is a substance comprising: Where R is hydrogen or according to The groups, in which n = 0 or 1, X = O or S, R1, R2, and R3 are hydrogen, halogen, nitro, substituted or unsubstituted alkyl, alkoxy, aromatic, or aryloxy groups, respectively. R4 can be alkyl, alkenyl, cycloalkyl, cycloalkenyl, or aralkyl. R5 is like R4, or an alkoxy group. Alternatively, N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, or N,N-dimethyl-N'-(3-chloro-4-methylphenyl)urea, or N,N-dimethyl-N'-(3-chloro-4-methoxyphenyl)urea, or N,N-dimethyl-N'(3-chloro-4-ethylphenyl)urea, or N,N-dimethyl-N'-(4-methyl-3-nitrophenyl)urea, or N-(N'-3,4-dichlorophenylcarbamoyl)morpholine, or N,N-dimethyl-N'(3-chloro-4-methylphenyl)thiourea. Or it could be a mixture of two, three, or more of the aforementioned types.

28. The method of claim 27, wherein n is 1 and / or X is 0.

29. The method of claim 27, wherein the aralkyl group is an aralkyl group substituted with a halogen, a hydroxyl group, or a cyano group.

30. The method of claim 29, wherein R4 is methyl, ethyl, propyl or butyl.

31. The method of claim 30, wherein R4 is a methyl group.

32. The method of claim 27, wherein R5 and R4 form a heterocyclic ring.

33. The method of claim 27, wherein the urea derivative is 4,4'-methylenebis(phenyldimethylurea).

34. The method according to any one of claims 1 to 5, wherein steps C) to F) are performed with a stroke rate of at least 80 strokes per minute.

35. The method of claim 34, wherein steps C) through F) are performed using a number of strokes between 120 / min and 300 / min.

36. The method according to any one of claims 1 to 5, wherein from the molded stack formed by filling the positioning area with molded parts, the stacked sections that are separated from each other by the adhesive coating with reduced effect or equipped with a rated break point are individually removed.

37. A laminated iron core for an electric motor, characterized in that, The motor is manufactured into a stacked body section using the method according to any one of claims 1 to 36.

38. The laminated iron core for an electric motor according to claim 37, wherein the laminated iron core for an electric motor is designed as a stator or as a rotor.

39. An electric motor, characterized in that, Including the laminated iron core for motors as described in claim 38, which serves as the stator and / or rotor.

40. The motor of claim 39, comprising a stator and a rotor, wherein the stator is partially or entirely a laminated iron core for motors according to claim 37 or 38, and the rotor is partially or entirely a structural element manufactured by means of specialized stamping and stacking.

41. The motor according to claim 39 or 40, wherein the motor is an electric motor.

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