Method and device for manufacturing sheet metal bundles from sheet metal sheets

Abstract

The invention relates to a method and device for producing laminated cores (2) from sheets (1), wherein an adhesive medium is applied as at least one adhesion point (22) to the upper surface of an insulating sheet (21) of a metal sheet strip (5), which is guided horizontally with respect to the direction of gravity, by means of an application unit (35) via an application head (32). The advantages for structure and function derive from the fact that the adhesive medium is transferred as at least one adhesion point (22) to the surface of the insulating sheet (21) of the metal sheet strip (5) or of a sheet (1) cut from this strip without any moving components in the application head (32), which moves perpendicularly with respect to the surface of the metal sheet strip (5) to transfer the adhesive medium in the form of at least one adhesion point (22).

Description

[0001] The invention relates to a method for producing sheet metal stacks from sheet metal lamellae, in which an adhesive medium is applied as at least one adhesive point to the upper surface of a sheet metal insulation layer of a sheet metal strip guided horizontally with respect to the direction of gravity by means of an application unit via an application head. The invention further relates to a device with an application unit for producing sheet metal stacks from sheet metal lamellae, comprising an application head, at least one distributor for the adhesive medium with at least one feed for the adhesive medium, and a frame for receiving the distributor(s) and the at least one application head.

[0002] A method and apparatus for producing sheet metal stacks from sheet metal lamellae of this type are specified in WO 2022 / 009878 A1. In this method, an upper stamping part contains an application head for adhesive, and the adhesive is applied during the stamping movement.

[0003] Another method and device for producing sheet metal stacks from sheet metal lamellae by applying adhesive and a device designed for this purpose are also shown in KR 2016 0145289 A.

[0004] Another method and apparatus for producing sheet metal stacks from sheet metal lamellae are specified in EP 1 833 145 B1.

[0005] The production of laminated cores for electrical machines (motors, generators) is economically achieved through a stamping process. A coil, whose magnetic properties, insulation layer, and width are already tailored to the laminated core being produced, is fed from a reel into a stamping press. A straightening unit is often located downstream of the reel. The feed system on the stamping press conveys the coil's sheet metal strip incrementally into the stamping die. The step size is also tailored to the laminated core being produced. Inside the stamping press, the stamping die incrementally creates the internal contours of the sheet metal strips. Once the internal contours are complete, the sheet metal strip is punched out of the coil's sheet metal strip using a punch and transferred to the die.To produce a sheet metal stack, the sheet metal lamellae are joined together in the punching die. With each stroke of the stamping press, the stack grows. A stack brake located below the punching die provides the necessary counterforce to join the sheet metal lamellae into the stack. With each stroke of the stamping press, the sheet metal stacks within the punching die and stack brake are moved downwards by the thickness of the sheet metal lamellae. Stack separation occurs when the stack joining mechanism is briefly suspended, preventing two adjacent sheet metal lamellae from joining. Multiple sheet metal stacks can be contained within the stack brake.After the sheet metal stacks have been transported through the stack brake, the sheet metal stack located at the lower end of the stack brake is usually transferred to a conveyor system, which conveys the completed sheet metal stacks out of the stamping press.

[0006] Various methods are used to join the sheet metal lamellae into sheet metal stacks within the stamping process, namely stamping stacking, back stacking and adhesive stacking.

[0007] Stamping and stacking creates a point-like connection between adjacent sheet metal lamellae. In this process, embossed studs are introduced into each lamella. In the die, the studs of adjacent lamellae are pressed together. The frictional force of the interlocked studs generates the holding force between the adjacent lamellae, thus gradually forming a sheet metal stack. The stack is separated by punching a recess that is dimensioned and positioned so that no studs can be introduced at this point, at least once. Therefore, at least once, two adjacent lamellae cannot be joined in the die. Stamping and stacking is a globally used method for manufacturing sheet metal stacks.However, the embossed bumps introduced in this process lead to electrical contact between adjacent sheet metal lamellae, which results in so-called iron losses and thus reduces the efficiency of electrical machines.

[0008] Backpacking is a special method for manufacturing sheet metal stacks from sheet metal lamellae. It involves the insulating layer of the coil's sheet metal strip possessing additional adhesive properties. These adhesive properties are selected to be activated only by heat and / or an activator. The adhesive properties of the insulating layer ensure a full-surface bond between the sheet metal lamellae. Such a process is described in EP 2 450 189 A1, and it can be integrated into the stamping process. The equipment required to integrate the backpacking process into the stamping process is complex and therefore costly and maintenance-intensive.

[0009] The adhesive packaging process, as described in the aforementioned EP 1 833 145 B1, eliminates the efficiency disadvantage of stamping packaging and the high energy consumption of back-packing. In this process, adhesive dots are applied in droplet form to the insulation layer of the metal strip. Adjacent metal lamellae are pressed together in the die of the stamping tool. During this process, the adhesive dots are distributed across the surfaces of adjacent lamellae. As the strip passes through the pack brake located below the die, the time is sufficient for the adhesive to bond with the metal lamellae to such an extent that the stacks achieve at least a hand-strength upon exiting the pack brake. This type of adhesive packaging creates a continuous bond between the metal lamellae in the area of ​​the application dots, without negatively affecting the magnetic properties of the metal strip and thus the final product.In this adhesive bundling process integrated into the stamping process, adhesive dots are applied to the top and / or bottom of the strip surface using a piezo micro-dispensing system. The application unit consists of at least one non-contact application head and at least one actuator connected to a controlled valve, which is equipped with a piezoelectric crystal. These actively moving parts within the application unit enable the adhesive to be applied to the underside as well. Bundle separation occurs when the system control sends an interruption signal to the piezo micro-dispensing system to stop the adhesive dot application. Recesses are provided in the tool, dies, and guides to protect the adhesive dots applied to the metal strip.The necessary facilities for integrating the adhesive packaging process into the stamping process are therefore also complex, maintenance-intensive and thus also costly.

[0010] DE 203 18 993 U1 discloses an adhesive packaging method in which a cutting die preferably has a flat end face, which can also be interrupted and thus contain recesses. It is shown that adhesive dots are applied to the underside of the metal strip. This adhesive packaging method is based on the strip material coming into contact with the surface of the metering unit, which moves a ball and thus releases the adhesive flow.

[0011] EP 3 217 520 A1 and, similarly, KR 101566486 B1 disclose an adhesive packaging process in which an application unit for the adhesive medium is integrated into the lower part of the die-cutting tool. The adhesive medium is supplied under pressure and at a predetermined flow rate to outlet nozzles for application to the underside surface of the sheet metal strip. An activator for the adhesive medium can be applied together with strip lubrication. Any excess adhesive droplets that are not transferred can be drained away through channels in the lower part of the die.

[0012] JP 2001321850 A presents an adhesive packaging process in which adhesive droplets are applied to the metal strip within the die-cutting tool. The strip is cleaned before the adhesive droplets are applied. The curing of the adhesive can be accelerated by applying heat in the packaging brake.

[0013] In an adhesive bundling process described in DE 35 35 573 A1, where bundle separation is controlled by measuring the thickness of a fed sheet metal strip, the individual lamellae are bonded into sheet metal bundles during the stamping process using an adhesive medium applied via a metering device. The adhesive is supplied via a hose from the metering device to the die-cutting punch and, with or without the hose, through the die-cutting punch. A heating device can be provided in the channel below a stamped part discharge device and a bundle brake to aid adhesive curing. If a two-component adhesive is used, metering occurs directly through the hose channel of the pressure plate and the cutting die insert. The activator is applied to the underside of the stamped part at the predetermined bonding points using commercially available metering needles, with a phase shift.When using one-component adhesive, the adhesive is applied to the underside of the stamped part using the dispensing needle device via the dispensing needles.

[0014] All adhesive packaging processes known on the market for the production of sheet metal packages from sheet metal lamellae use elaborate distribution and metering or application systems for the adhesive medium and / or tend to become contaminated in the area of ​​the application head.

[0015] The invention is based on the objective of providing a method or device of the type mentioned above which offers the simplest possible, lowest maintenance and therefore cost-effective application method for applying adhesive dots to the surface of the sheet metal strip or sheet metal lamellae.

[0016] This problem is solved according to the invention in the production of sheet metal stacks according to the method with the features of claim 1 and in the device with the features of claim 13.

[0017] The method provides that the adhesive medium is transferred as at least one adhesive point onto the surface of the sheet metal insulation of the sheet metal strip or a sheet metal lamella cut from it without moving components in the application head, wherein the application head is moved perpendicularly relative to the surface of the sheet metal strip to transfer the adhesive medium in the form of the at least one adhesive point.

[0018] In the embodiment of the method according to the invention, for an exact transfer of the adhesive medium to the sheet insulation or the sheet lamella, it is provided that the transfer of the adhesive medium as an adhesive point onto the sheet insulation of the sheet strip or the sheet lamella is supported by the kinetic energy of a distributor of the application unit and the application head, and the gravity of the adhesive medium with or without use of the adhesive force of the adhesive point on the sheet strip.

[0019] The device is designed so that the distributor is manufactured using an additive manufacturing process, in particular a 3D printing process.

[0020] These measures advantageously integrate the adhesive bonding process into the manufacturing process of the sheet metal stacks, either during or after the stamping process. Detailed investigations by the inventors have shown that these measures allow the adhesive supply for applying the adhesive dots to be precisely controlled or regulated according to specifications, without requiring a complex feed unit design or moving components in the application head. Contamination of the metering system, particularly the application head, is thus largely avoided.By feeding the adhesive medium onto the top surface of the sheet insulation while the application head moves perpendicular to the direction of gravity—that is, without any moving parts or their actuation as in prior art—the adhesive medium is detached in a precisely predefinable quantity under the influence of gravity and the adjustable kinetic energy. The influence of a cohesive force can also be taken into account, if necessary. This combination of physical forces, along with the simple design of the application unit, results in a precise, reliable, and economical application system for the adhesive medium in the packaging of sheet metal lamellae. It should be noted that the term "-point" here is not to be understood in a strictly mathematical sense, but rather, appropriate to the practical situation, has a geometric dimension due to its volume.

[0021] The device for manufacturing the sheet metal stacks can be easily and optimally adapted to the application of the adhesive medium with the aforementioned parameters by means of the design of the distributor (in which no moving parts are arranged) using the additive process, in particular the 3D printing process, with high accuracy, any channel routing with any channel cross-sections and connection geometries for the application head(s).

[0022] Advantageous embodiments of the invention are specified in the dependent claims.

[0023] When integrating the adhesive application into the die-cutting process, it is advantageous to ensure that the application head is moved synchronously with the working stroke of the die-cutting press.

[0024] Particularly when the application of the adhesive medium is downstream of the die-cutting process, an advantageous design consists in the fact that the application head is not moved synchronously with the working stroke of the die-cutting press.

[0025] Advantageously, the required volume of the adhesive medium at the application head is provided by the pressure height and pulse duration depending on the viscosity of the adhesive medium and the kinetic energy of the application head (also in coordination with the design of the application head).

[0026] Further measures contribute to the precise function and integration of the process into the manufacturing process of the sheet metal package by ensuring that the application head does not touch the surface of the sheet metal insulation of the sheet metal strip or sheet metal lamella when dispensing the adhesive medium, wherein the distance between the application head and the sheet metal strip or sheet metal lamella is at most 5 mm, preferably at most 1 mm.

[0027] For a precisely controlled application of the adhesive medium to form the best possible adhesive surface or bond between the sheet metal lamellae, it is further advantageous that the surface of the sheet metal insulation of the sheet metal lamella is only partially wetted during the application of the adhesive dots.

[0028] Further advantageous measures for forming the adhesive surfaces consist of the application of the adhesive dots to the sheet insulation of the sheet metal strip or the sheet metal lamella being monitored by sensors for the presence and size of partial wetting.

[0029] Furthermore, adjusting the volume of each adhesive point contributes to a precise alignment of the adhesive surface on the sheet metal lamellae.

[0030] High quality of the bonding surfaces during the manufacturing process and the adhesive bond is also ensured by the fact that the volume of each adhesive point is automatically regulated by a control loop.

[0031] A uniform application of the adhesive medium to optimize the bonding surfaces is further supported by applying multiple adhesive dots to the surface of the sheet metal strip or sheet metal lamella via at least one distributor with at least one feed for the adhesive medium and via the at least one application head connected to the distributor. One or more application heads can be attached to a distributor, with each application head, for example, being able to apply only one adhesive dot per movement. In an alternative configuration, multiple adhesive dots can also be applied with one application head.

[0032] Integrating the adhesive application into the die-cutting process is achieved by placing the application unit for the adhesive dot within the die-cutting process.

[0033] A further advantageous application of the adhesive medium consists in the fact that the application unit for the application of the adhesive medium is located outside the die-cutting process, in particular downstream of it.

[0034] An advantageous further embodiment of the method consists in the fact that the distributor and the application head for applying the adhesive medium are located within the punch of the die-cutting tool.

[0035] The device is advantageously designed in that the at least one distributor for the adhesive medium is made of a metallic material or that the at least one distributor for the adhesive medium is made of a non-metallic material, in particular a plastic, preferably a thermosetting plastic.

[0036] A particularly advantageous design for the device, both in terms of construction and function, is that the application head contains no moving components, especially no driven components. This design, in conjunction with the additive manufacturing process for the distributor, results in an application system that is well-adapted to the required function and operates largely without malfunctions.

[0037] Precise operation and reliable monitoring of consistently high adhesive application quality are further enhanced by the presence of a sensor, particularly an optical sensor, that monitors the presence and extent of partial wetting of a metal strip or sheet metal lamellae by the adhesive points. This monitoring by the sensor occurs either during or after the adhesive application. The term "sensor" is to be understood in a broad sense, meaning that the optical sensor could also be, for example, a camera system for image processing to perform a target-actual comparison.

[0038] A further embodiment that is advantageous for the function and structure of the device consists in the fact that the volume of the adhesive points is adjustable, in particular independently by a control loop with a sensor for monitoring the partial wetting of the sheet metal strip or the sheet metal lamellae with the adhesive points.

[0039] High-quality application and distribution of the adhesive medium are further supported by ensuring that the distance between the application heads is no more than 5 mm, preferably no more than 3 mm. Larger distances may be considered depending on the product.

[0040] The invention is explained in more detail below with reference to exemplary embodiments and the drawings. The drawings show: Fig. 1 a schematic representation of a device for producing a lamination stack from a sheet metal strip unwound from a coil in a stamping process with a stamping press and a device for stacking sheet metal lamellae to form the lamination stack, Fig. 2 a lamination stack formed from a number of sheet metal lamellae in a perspective view, Fig. 3 a section of a sheet metal strip consisting of a magnetic core material and insulating layers applied to both sides, onto which an adhesive dot is applied, in a sectional view, Fig. 4 a simplified representation of an embodiment of a stamping tool arranged in the stamping process, in which a sheet metal strip is processed step by step into sheet metal lamellae and a lamination stack, consisting of areas for producing the inner contours of the sheet metal lamellae, a punch, a die, and a stack brake in a side view, Fig.Fig. 5 A schematic representation of an application unit integrated into the stamping process according to the invention, comprising a frame, a distributor with a feed for the adhesive medium, several application heads, and a sensor for monitoring the application of the adhesive dots to the sheet metal strip; Fig. 6 An application unit downstream of the stamping process according to the invention, comprising a frame, a distributor with a feed for the adhesive medium, and several application heads for applying the adhesive dots to the sheet metal strip; Fig. 7 A distributor integrated according to the invention with a feed for the adhesive medium and several application heads for applying the adhesive dots to the sheet metal strip in a punch of the stamping tool; and Fig. 8 An embodiment of a distributor in a perspective glass view, manufactured using a 3D printing process.

[0041] Fig. 1 Figure 1 schematically shows a device for producing sheet metal stacks 2 from sheet metal lamellae 1 in large quantities within a stamping process 3. A sheet metal stack 2 made from a multitude of sheet metal lamellae 1 is shown by way of example in Figure 2. Fig. 2 depicted.

[0042] To produce the sheet metal stacks 2, a sheet metal strip 5 is unwound from a coil 4 using a reel 6, optionally fed to a straightening unit 7, and gradually fed into a working chamber of a stamping press 9 and a stamping die 10 by means of a feed system 8. How Fig. 3 As shown in part, the sheet metal strip 5 consists of a (magnetic) core material 20 with insulating layers 21 applied to both sides of it.

[0043] Within the punching tool 10, positioning holes are first punched into the sheet metal strip 5 to ensure a precise step size for the stepwise advancement of the sheet metal strip 5 within the punching tool 10. Subsequently, in the punching tool 10, the inner contours of the sheet metal lamella 1 are stepwise punched into the sheet metal strip 5 in the areas 40 for producing the inner contours. When all the inner contours of the sheet metal lamella 1 to be pre-punched into the sheet metal strip 5 have been punched into the sheet metal strip 5, the sheet metal lamella 1 is punched out of the sheet metal strip 5 with a punch 43 and transferred to a die 41 with an underlying pack brake 42 (see Figure 41). Fig. 4 ).

[0044] Fig. 5 Figure 1 shows an embodiment of the invention in which an application unit 35 for an adhesive medium for bonding the stacked sheet metal strips 1 is located in the working area of ​​the stamping press 9 between the feed system 8 and the stamping die 10. The sheet metal strip 5, whose width and thickness are matched to the outer dimensions of the sheet metal strips 1, is fed stepwise to the stamping die 10 by the feed system 8, the step size being adapted to the outer diameter of the sheet metal strip 1. The sheet metal strip 5 also passes stepwise through the application unit 35. The application unit 35 is positioned in the working area of ​​the stamping press 9 such that adhesive dots 22 can be applied to the insulating layer 21 of the sheet metal strip 5 in the correct orientation (see Figure 1). Fig. 3 ).

[0045] The application unit 35 consists of a frame 30 in which a distributor 31 is attached. Application heads 32 are attached to the distributor 31, and their number and position are selected and arranged such that adhesive dots 22 can be applied to the sheet metal strip with precise positioning, as long as the sheet metal strip is not moved by the feed system.

[0046] For the application of the adhesive dots 22 to the sheet metal strip 5, an adhesive medium is supplied in pulses from a separate adhesive container (not shown here, usually located in a pneumatic and fluidics section of a control cabinet) spaced apart from the application unit 35. This container is typically located in a pneumatic and fluidics section of a control cabinet. A metering pump or a compressed air valve (which generates pressure in the adhesive container) feeds the adhesive medium through a feed 34 to the distributor 31 and the application heads 32 attached to it. The pulse frequency for supplying the adhesive medium is synchronized with the operating frequency of the stamping press 9. The pulse duration and pressure are set so that the adhesive dots 22 on the sheet metal strip 5 reach a defined size. The distributor 31 has a channel system that distributes the adhesive medium evenly to the application heads 32. A plate of the frame 30, to which the distributor 31 with the application heads 32 is attached, can be tilted (with respect to the direction of gravity).move (geodesically) vertically down and upwards. The vertical movement can be synchronous or asynchronous with the working stroke of the stamping press 9.

[0047] When the adhesive medium is available at the lower end of the application heads 32, the distributor 31 and the application heads 32 are moved vertically in the frame 30 towards the sheet metal strip 5 until the application heads 32 do not touch the sheet metal strip 5. The distance between the application heads 32 and the sheet metal strip 5 is at most 5 mm, preferably at most 1 mm. Assisted by the kinetic energy of the distributor 31 and the application heads 32, the force of gravity on the adhesive medium at the lower end of the application heads 32, and optionally also an adhesive force acting on the sheet metal strip 5, the adhesive medium is transferred to the top surface of the sheet metal strip 5 in the form of adhesive dots 22. Once the adhesive dots 22 have been transferred to the sheet metal strip 5, the distributor 31 with the application heads 32 is moved vertically upwards again in the frame 30, and after completion of the punching operation in the punching tool 10, the sheet metal strip 5 is advanced one step further by the feed system 8.

[0048] The adhesive dot application is repeated until the required number of sheet metal strips 1 with adhesive dots 22 for the production of the sheet metal stack 2 is reached. Then, to separate the stack, the application of the adhesive dots 22 onto the sheet metal strip 5 is interrupted once by temporarily suspending the pulse for supplying the adhesive medium 34 to the distributor 31 and the application heads 32. Stack separation can be facilitated by simultaneously suspending the vertical movement of the distributor 31 and the application heads 32 at the same time as the pulse for supplying the adhesive medium is suspended.

[0049] Monitoring of the successful application of the adhesive dots 22, in particular the presence and size or volume of the adhesive dots 22 on the sheet metal strip 5, is carried out with one or more sensors 33 downstream of the application unit 35. In a special embodiment, the size of the adhesive dots 22 is controlled by the pulse duration and the pressure for supplying the adhesive medium via the sensors 33 for monitoring the size of the adhesive dots 22.

[0050] After the adhesive dots 22 are applied to the sheet metal strip 5, the sheet metal strip 5 is gradually fed through the punching tool 10 and the inner contours of the sheet metal lamellae 1 are formed according to Fig. 4 In the areas 40, the inner contours are punched into the sheet metal strip 5. The punching unit of the punching tool 10 contains the punching die 43, which punches out a sheet metal lamella 1 from the sheet metal strip 5 with each stroke of the punching press 9 and transfers it to the punching die 41. When the punched-out sheet metal lamella 1 touches the sheet metal lamella 1 below it, the adhesive points 22 between the two adjacent sheet metal lamellae 1 are pressed together and thereby distributed evenly across the surfaces of the two adjacent sheet metal lamellae 1.

[0051] With each stroke of the stamping press 9, another sheet metal lamella 1 is pressed through the punch 43 into the die 41, and the stack of sheet metal lamellae 1 below is moved downwards by the thickness of the sheet. To allow time for the adhesive dots 22 distributed across the surface between the sheet metal lamellae 1 to cure and form the sheet metal stacks 2, the stack brake 42 is located below the die 41. This brake generates an axial holding force in the form of friction for the sheet metal stacks 2 within the die 41 and the stack brake 42 by means of a radial preload force. When a completed sheet metal stack 2 reaches the lower end of the stack brake 42, it is transferred there by gravity or by means of a lift system to a conveyor system 11, which conveys the completed sheet metal stacks 2 out of the stamping press 9.

[0052] At a Fig. 6 In the further embodiment of the invention shown, an application unit 35 is arranged downstream of the stamping process 3. This design allows further processing steps on the sheet metal lamellae 1, such as thermal treatment, to be carried out between the stamping process 3 and the application of the adhesive dots 22 to the insulating layer 21 of the sheet metal lamellae. These processing steps can weaken or destroy a previously created adhesive bond between the sheet metal lamellae 1 and the sheet metal stack 2.

[0053] The application unit 35 in turn has a frame 30 in which a distributor 31 is attached. The application heads 32 are attached to the distributor 31, which has a feed for the adhesive medium 34. The number and position of the application heads are selected and arranged so that adhesive dots 22 can be applied to the sheet metal lamella 1 with precise positioning.

[0054] First, a sheet metal strip 1 is inserted into the application unit 35, either manually or automatically, with precise positioning. To apply the adhesive dots 22 to the sheet metal strip 1, an adhesive medium is supplied via the adhesive medium feed 34 in the distributor 31 and the application heads 32 attached to it with a pulse. The pulse duration and pressure are set so that the adhesive dots 22 on the sheet metal strip 1 reach a defined, predetermined size or volume. The distributor 31 has a channel system that distributes the adhesive medium evenly to the application heads 32. A plate of the frame 30, to which the distributor 31 with the application heads 32 is attached, can be moved vertically up and down. This vertical movement can be driven manually or automatically.If the adhesive medium is available at the lower end of the application heads 32, the distributor 31 and the application heads 32 are moved vertically in the frame 30, either manually or automatically, towards the sheet metal lamella 1 until the application heads 32 do not touch the sheet metal lamella 1. The distance between the application heads 32 and the sheet metal lamella 1 is at most 5 mm, preferably at most 1 mm. Assisted by the kinetic energy of the distributor 31 and the application heads 32, the force of gravity on the adhesive medium at the lower end of the application heads 32, and any adhesive force of the adhesive medium on the sheet metal lamella 1, the adhesive medium is transferred to the upper surface of the sheet metal lamella 1 in the form of adhesive dots 22. Once the adhesive dots 22 have been transferred to the sheet metal lamella, the distributor 31 with the application heads 32 is moved vertically upwards in the frame to its initial position.

[0055] The sheet metal lamella 1 is then manually or automatically removed from the application unit 35 and fed into a stacking unit, where the sheet metal lamellae 1 are stacked and pressed together with precise positioning. Pressing adjacent sheet metal lamellae 1 together distributes the adhesive points 22 evenly between the lamellae. Under pressure and time, the adhesive points or bonding surfaces harden, and adjacent sheet metal lamellae 1 are joined to form sheet metal stacks 2. Completed sheet metal stacks 2 are removed from the stacking unit manually or automatically.

[0056] At a Fig. 7 In the third embodiment of the invention shown, the distributor 31 and the application heads 32 are integrated into the punch 43 within the die 10. This embodiment advantageously results in particularly short distribution paths for the adhesive medium.

[0057] For the application of the adhesive dots 22 to the sheet metal strip 5, an adhesive medium is also supplied in a pulsating manner to the distributor 31 and the application heads 32 attached thereto via a feed for the adhesive medium 34, according to this embodiment as well.

[0058] The pulse frequency is synchronized with the operating frequency of the stamping press 9. The pulse duration and pressure are set so that the adhesive dots 22 on the sheet metal strip 5 reach a defined size. The distributor 31 has a channel system that distributes the adhesive medium evenly to the application heads 32. The supply of the adhesive medium to the lower ends of the application heads 32 begins at the earliest when the punch 43 is moved upwards during the upward movement of the press ram and has reached a distance of at least 1 mm to the surface of the previously stamped sheet metal strip 1. The supply of the adhesive medium to the lower end of the application heads 32 is completed at the latest when, during the downward movement of the punch 43 by the press ram, the distance between the punch 43 and the sheet metal strip 5 is still at least 1 mm.When the punch 43 touches the metal strip 5 during its downward movement and the punching process of the metal strip 1 from the metal strip 5 begins, the adhesive medium is transferred from the applicator heads 32 to the metal strip in the form of adhesive dots 22. The applicator heads 32 do not touch the metal strip 5 during the application of the adhesive medium, with the distance between the applicator heads 32 and the metal strip 5 being at most 5 mm, preferably at most 1 mm. Assisted by the kinetic energy of the distributor 31 and the applicator heads 32 in the punch 43, the force of gravity on the adhesive medium at the lower end of the applicator heads 32, and any adhesive force of the adhesive medium on the metal strip 5, the adhesive medium is transferred to the upper surface of the metal strip 5 in the form of adhesive dots 22.When the adhesive points 22 are transferred to the sheet metal strip 5, the punching process of the sheet metal lamella 1 from the sheet metal strip is completed and the punching die 43 has safely left the sheet metal strip 5 during its upward movement, the sheet metal strip 5 is moved one step further by the feed system 8.

[0059] The application of adhesive dots is repeated until the required number of sheet metal lamellae 1 with adhesive dots 22 for the production of the sheet metal package 2 is reached.

[0060] Then, to separate the packages, the application of the adhesive dots 22 onto the metal strip 5 is interrupted once by temporarily suspending the impulse for supplying the adhesive medium 34 to the distributor 31 and the application heads 32. Package separation can be further supported by simultaneously lifting the distributor 31 and the application heads 32 within the punch 43 by at least 0.5 mm under automatic drive at the same time as the impulse for supplying the adhesive medium is suspended.

[0061] With each stroke of the stamping press 9, a sheet metal lamella is punched out of the sheet metal strip 5 and transferred to the die. When the punched-out sheet metal lamella 1 touches the sheet metal lamella 1 below it, the adhesive points 22 between the two adjacent sheet metal lamellae 1 are pressed together and thereby distributed evenly across the surfaces of the two adjacent sheet metal lamellae 1.

[0062] With each stroke of the stamping press 9, another sheet metal lamella 1 is pressed through the punch 43 into the die 41, and the stack of sheet metal lamellae 1 below is moved downwards by the sheet thickness. To allow time for the adhesive bonds between the sheet metal lamellae 1 to cure and form the sheet metal stacks 2, the stack brake 42 is located below the die 41. This brake generates an axial holding force in the form of friction for the sheet metal stacks 2 within the die 41 and the stack brake 42 by means of a radial preload force. When a completed sheet metal stack 2 reaches the lower end of the stack brake 42, it is transferred there by gravity or a lift system to a conveyor system 11, which conveys the completed sheet metal stacks 2 out of the stamping press 9.

[0063] Figur 8Figure 1 shows an example of a distributor 31, manufactured using a 3D printing process, with an internal distribution channel 50 that introduces the adhesive medium from the adhesive medium feed 34 into the distributor 31 via the interface 51 or connection point. Within the distributor 31, the adhesive medium is guided via the channel system 50 to the three additional interfaces 52 and transferred there to the application heads 32. Alternatively, more or fewer than three additional interfaces may be present. The special shape of the distribution channel 50 is advantageously manufactured using a 3D printing process with a thermosetting plastic.

Claims

1. Method for producing laminated cores (2) from laminations (1), in which an adhesive medium is applied as at least one adhesive point (22) to the upper side of the surface of a sheet metal insulation (21) of a sheet metal strip (5) guided horizontally with respect to the direction of gravity by means of an application unit (35) via an application head (32), wherein the adhesive medium is transferred as at least one adhesive point (22) to the surface of the sheet metal insulation (21) of the sheet metal strip (5) or a lamination (1) cut from the strip without movable components in the application head (32), and wherein the application head (32) is moved perpendicularly relative to the surface of the sheet metal strip (5) in order to transfer the adhesive medium in the form of the at least one adhesive point (22), wherein the transfer of the adhesive medium as an adhesive point (22) to the sheet metal insulation (21) of the sheet metal strip (5) or of the lamination (1) is supported by the kinetic energy of a distributor (31) of the application unit (35) and the application head (32), and the gravitational force of the adhesive medium with or without using the adhesive force of the adhesive point (22) on the sheet metal strip (5).

2. Method according to claim 1, characterized in that the application head (32) is moved synchronously with the working stroke of the punching press (9).

3. Method according to claim 1, characterized in that the application head (32) is not moved synchronously with the working stroke of the punching press (9).

4. Method according to any of the preceding claims, characterized in that the application head (32) does not touch the surface of the sheet metal insulation (21) of the sheet metal strip (5) or the lamination (1) when dispensing the adhesive medium, the distance between the application head (32) and the sheet metal strip (5) or the lamination (1) being at most 5 mm, preferably at most 1 mm.

5. Method according to any of the preceding claims, characterized in that the surface of the sheet metal insulation (21) of the lamination (1) is only partially wetted during the application of the adhesive points (22).

6. Method according to any of the preceding claims, characterized in that the application of the adhesive points (22) to the sheet metal insulation (21) of the sheet metal strip (5) or the lamination (1) is monitored by sensors (33) for the presence and size of partial wetting.

7. Method according to any of the preceding claims, characterized in that the volume of the relevant adhesive point (22) is adjusted.

8. Method according to any of the preceding claims, characterized in that the volume of the relevant adhesive point (22) is regulated independently by a control circuit.

9. Method according to any of the preceding claims, characterized in that the application of several adhesive points (22) to the surface of the sheet metal strip (5) or the lamination (1) takes place via the distributor (31) with at least one feed for the adhesive medium (34) and via the application head (32) connected to the distributor (31).

10. Method according to any of the preceding claims, characterized in that the application unit (35) for applying the adhesive point (22) is located within the punching process (3).

11. Method according to any of claims 1 to 10, characterized in that the application unit (35) for applying the adhesive medium (22) is located outside the punching process (3), in particular downstream thereof.

12. Method according to any of claims 1 to 10, characterized in that the adhesive medium is applied by means of an embodiment in which the distributor (31) and the application head (32) are located inside the punching stamp (43) of the punching tool (10).

13. Device for carrying out the method according to claim 1, comprising an application unit (35) for producing laminated cores (2) from laminations (1), which has an application head (32), at least one distributor (31) for the adhesive medium with at least one feed for the adhesive medium (34) and a frame (30) for receiving the distributor(s) (31) and the at least one application head (32), characterized in that the distributor (31) is produced using an additive method, in particular a 3D printing method.

14. Device according to claim 13, characterized in that the at least one distributor (31) for the adhesive medium is made of a metal material.

15. Device according to claim 14, characterized in that the at least one distributor (31) for the adhesive medium is made of a non-metal material, in particular a plastics material, preferably a thermosetting plastics material.

16. Device according to claim 13 to 15, characterized in that the application head (32) does not contain any movable components, in particular no driven components.

17. Device according to any of claims 14 to 16, characterized in that a sensor (33), in particular an optical sensor (33), is present which monitors the presence and the size of the partial wetting of a sheet metal strip (5) or the lamination (1) with the adhesive points (22), the monitoring by the sensor (33) taking place during the application of the adhesive medium or taking place downstream of the application of the adhesive medium.

18. Device according to any of claims 13 to 17, characterized in that the volume of the adhesive points (22) is adjustable, in particular independently by a control circuit with a sensor (33) for monitoring the partial wetting of the sheet metal strip (5) or the lamination (1) with the adhesive points (22).

19. Device according to any of claims 13 to 18 comprising several application heads, characterized in that the distance between the application heads (32) is at most 5 mm, preferably at most 3 mm.

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