Method for manufacturing lamellae for a lamella pack, in particular for electrical machines and generators, apparatus with at least one stamping press, and lamella and lamella pack manufactured according to the method

Abstract

Method for producing lamellae (10) for a lamella pack (14), in particular for electrical machines and generators, from a metal strip (3), in which the lamella (10) is punched out of the metal strip (3) using at least one punching tool (13), characterized in that the entire contour (9) of the lamella (10) with the exception of connection points (11) to the metal strip (3) is produced by jet cutting, wherein the metal strip (3) remains stationary during the jet cutting, that the connection points (11) are subsequently cut through by the punching tool (13) to remove the lamella (10) from the metal strip (3), and that the lamellae (10) are subsequently stacked to form the lamella pack (14).

Description

[0001] The invention relates to a method for producing lamellae for a lamella pack, in particular for electrical machines and generators, according to the preamble of claim 1, a device with at least one stamping press according to the preamble of claim 7, a lamella produced according to the method according to claim 12 and a lamella pack produced according to the method according to claim 13.

[0002] Electrical machines frequently use laminated cores made of stacked laminations, which are produced from cut electrical steel sheets. Such laminated cores are used, for example, in the rotors and / or stators of electric motors. A metal strip is unwound from a reel and fed into a stamping press. This press has at least one die that cuts the contours of the laminations in one or more stations and one or more tracks. The laminations produced in this way can be stacked inside and outside the die to form a laminated core and joined together within the core. Different lamination contours require a separate die for each. Such dies are expensive, and replacing them brings the stamping press to a standstill.

[0003] It is also known to feed the metal strip into a laser system and cut the contours of the lamella within a laser cutting machine at one or more stations. The cut lamellae are then individually removed and assembled into a package outside the laser system. This method is also complex and expensive.

[0004] A method is also known (DE 100 40 978 A1) in which a laser head can be used to cut out an essentially circular outer contour of the subsequent sheet metal, or both to cut out a rough contour and to weld.

[0005] In both cases, jet cutting is not used to create the entire contour of the lamella. After the rough contour is cut, the workpiece is fed to a slotting machine with a punch. The sheet metal is rotated by a drive unit, and the punch, using a vertical punching motion, cuts slots evenly spaced around the inner circumference of the lamella. By incrementally rotating the sheet metal, the slotting machine successively cuts all the slots on either the inner or outer circumference of the sheet metal. The sheet metal is already completely detached from the metal strip so that it can be incrementally rotated around its axis by the drive unit during the slotting process.

[0006] DE 10 2008 043 138 A1 describes a process in which end lamellae or individual lamellae can be produced by a punching process or by jet cutting. The lamellae are thus separated from the metal strip by only one cutting method.

[0007] It is also known from DE 10 2007 029 719 A1 to separate the lamellae from the metal strip in a conventional manner using only one cutting method, namely either by punching or by jet cutting.

[0008] Furthermore, a method is known (DD 2 08 927 A1) in which the lamellae are punched out of the metal strip by a punching process in several stages.

[0009] The invention is based on the objective of designing the generic method, the generic device, the lamella and the lamella pack in such a way that simple manufacturing of the lamella is possible even with different contours.

[0010] This problem is solved in the generic method according to the invention with the characterizing features of claim 1, in the generic device according to the invention with the characterizing features of claim 7, in the lamella with the features of claim 12 and in the lamella pack with the features of claim 13.

[0011] In the inventive method, the contour of the lamella is first produced, at least partially, by jet cutting in the metal strip, with the metal strip remaining stationary during the jet cutting process. The method is carried out in such a way that the lamella is still held in the metal strip by the connecting points, preventing it from falling off. The connecting points are then severed with the punching tool, thus releasing the lamella from the metal strip. Since the contour, or at least a partial contour, of the lamella is produced by jet cutting, the lamella has very clean cutting edges that do not require any further processing. Of course, the lamella can be further processed at its cutting edge after punching if this should be necessary to meet very high accuracy requirements.Since the lamella is still connected to the metal strip after jet cutting, it is transported under the punching tool and only there detached from the metal strip. This allows the lamellae to be formed very easily, cost-effectively, and quickly. A necessary packing unit for applying or inserting the connecting elements is advantageously located between the jet cutting unit and the punching press.

[0012] It is advantageous if the slats are held in place by at least two connection points in the metal strip.

[0013] The lamellae are advantageously produced in a single track of the metal strip. In this case, a narrow strip is preferably used. A narrow strip is a metal strip produced by longitudinal slitting (shearing) from a wide strip. Before processing in the stamping process, the narrow strip is in coil form. The width of the narrow strip is determined by the dimensions of the product to be manufactured from it.

[0014] It is also possible to manufacture the lamellae in at least two tracks of the metal strip. In this case, a wide strip of metal is advantageously used. A wide strip is a metal strip whose width is determined by the manufacturing process. Upon delivery, the wide strip is wound into a coil. The edges of the wide strip may already be trimmed by the manufacturer. A typical width for a wide strip used to manufacture lamellae for electrical machines or generators is approximately 1200 mm.

[0015] The device according to the invention comprises, in addition to at least one punching press, at least one upstream jet cutting unit. It has at least one jet cutting head with which the contour of the lamella can be reliably cut. With the jet cutting head, even the most complex contours can be cut flawlessly from the metal strip with high precision. Furthermore, the use of the jet cutting head offers the advantage that a wide variety of contours can be produced in immediate succession in a single metal strip, since only the program control for the jet cutting head needs to be switched. The packing unit applies the connecting elements required to form the lamella pack to or inserts them into the metal strip.

[0016] To ensure flawless processing, a straightening device is advantageously placed upstream of the beam cutting unit.

[0017] In a preferred embodiment, the stamping press is provided with at least one stacking station for stacking the slats. The slat can then be ejected from the metal strip into the stacking station within the stamping press using the die.

[0018] The lamella according to the invention is characterized in that its contour is produced by jet cutting. Therefore, the contour has no punching indentation, no cut surfaces, no break, and no burr, as is regularly the case when lamellae are produced by stamping.

[0019] The subject matter of the application is not only defined by the subject matter of the individual patent claims, but also by all information and features disclosed in the drawings and the description. These are claimed as essential to the invention, even if they are not explicitly stated in the claims, insofar as they are novel, individually or in combination, compared to the prior art.

[0020] Further features of the invention will become apparent from the further claims, the description and the drawings.

[0021] The invention is explained in more detail with reference to an embodiment shown in the drawing. The drawing shows... Fig. 1 in schematic representation a device according to the invention for carrying out the method according to the invention, Fig. 2 a top view of the device according to Fig. 1 continuous Fig. 3 Fig. 3 a top view of a lamella, Fig. 4 slat packages on average.

[0022] The device has a beam cutting unit 1 in the form of a laser cutting unit and a subsequent punching press 2. A metal strip 3, which can be wide or narrow, is transported through the device. The metal strip 3 is wound into a coil 4, which is rotatably mounted on an unwinder 5. The metal strip 3 is optionally transported through a straightening unit 6, in which it is straightened. The metal strip 3 is then fed to the beam cutting unit 1 by means of a feed unit 7. The unit has at least one beam cutting head 8, with which program-controlled contours 9 can be cut in the metal strip 3. Optionally, in the packing unit 12, the connecting elements 16 required to form a lamella pack 14 are applied to or inserted into the metal strip 3.In the subsequent stamping press 2, a stamping tool 13 is used to stamp the lamella 10, which contains the contour 9, from the metal strip 3. To prevent the lamellae 10 from falling out of the metal strip 3 before being cut out in the stamping press 2, they are held and positioned by one or more connecting points 11 in the metal strip 3.

[0023] A CO2 laser is advantageously used as the beam source, with which the respective contours 9 in the metal strip 3 can be reliably cut with high accuracy.

[0024] The metal band 3 is, as can be seen from the Fig. 1 and Fig. 2 emerges, transported in its longitudinal direction through the jet cutting unit 1 and the punching press 2.

[0025] The desired contours 9 of the lamellae 10 to be punched out are precisely produced by the jet cutting unit 1. The jet cutting head 8 allows even the most complex contours to be cut from the metal strip 3 with high accuracy. The contours in the metal strip 3 can be successively different because the jet cutting head 8 can follow each path required to generate the different contours in the jet cutting unit 1 under program control. Unlike punching tools, which require a different tool for each different contour, the jet cutting unit 1 allows each suitable contour to be cut into the metal strip 3 sequentially and extremely cost-effectively.

[0026] During contour generation in the beam cutting unit 1, the metal strip 3 advantageously remains stationary, allowing for a clean cut. While the beam cutting head 8 follows its paths according to a program control during the beam cutting process, a lamella 10 with a contour 9 previously generated in the beam cutting unit 1 is simultaneously punched out of the metal strip 3 in the stamping press 2 using a stamping tool 13.

[0027] The packaging unit 12 applies the connecting elements 16 required to form a lamella pack 14 to or inserts them into the metal strip 3. A punching tool 13 in the punching press 2 ejects the lamella 10 from the metal strip 3. Fig. 2 The punching contour 17 of the punching tool 13 is marked by a dashed contour element. The lamella 10 is pressed downwards by the punching tool 13 into a stacking station 15, where the lamellae 10 are stacked into packages. In Fig. Figure 4 shows an example of such a lamella pack 14. The superimposed, punched-out lamellae can be mechanically connected to one another, for example, by rods passing through the lamellae. The lamellae can also be provided with wart-like protrusions that engage positively in corresponding recesses of the adjacent lamella. It is also possible to provide the lamellae with recesses and projecting tongues that engage in the recesses of the respective adjacent lamella. The width of the tongues can be smaller than the circumferential width of the openings. This allows adjacent lamellae within the pack to be twisted relative to each other. In the described configurations, the superimposed

[0028] The slats are securely connected to each other in a suitable manner, for example by rods penetrating the package. The package is held on these rods in a known manner.

[0029] The individual slats of package 14 can also be welded or glued together.

[0030] The joining of the individual lamellae within the package 14 can be carried out within the stamping press 2, but also outside of it in a separate processing station.

[0031] The device is characterized by the fact that the beam cutting unit 1 produces the geometry of the lamellae, or at least parts of the lamella geometry. The punching press 2 then serves only to separate the lamellae 10 from the metal strip 3 and to stack the punched-out lamellae 10 within the stacking station 15 to form the lamella pack 14.

[0032] Advantageously, a narrow strip is used as the metal strip 3. This allows the jet cutting unit 1 to be smaller, resulting in a compact device. The desired contours of the lamellae can be cut from the metal strip 3 with high precision using the jet cutting head 8. Even more complex shapes can be produced very accurately using the jet cutting head 8. The resulting edges of the lamellae 10 are characterized by clean cut surfaces. Compared to stamped lamellae, there is no risk of punch marks, breaks, or burrs on the cut surfaces.

[0033] Since the jet cutting head 8 is program-controlled, a wide variety of contours can be cut from the metal strip 3 within a very short time, if necessary. The appropriate program is simply loaded so that the jet cutting head 8 performs its desired movements over the metal strip 3.

[0034] When using a narrow strip for the metal strip 3, the lamellae 10 are cut one after the other in a single track from the metal strip 3, as shown in the diagram. Fig. As can be seen in Figure 2. Of course, a wide belt can also be used for the metal strip 3. Then the lamellae 10 can be cut from the metal strip 3 in two or more parallel tracks. The same or different lamellae can be cut in the different tracks. Only one jet cutting head 8 is required for the differently shaped lamellae. Naturally, the jet cutting unit 1 can also have two or more jet cutting heads 8. Such a configuration is advantageous, for example, if two or more metal strips 3 are fed side by side through the jet cutting unit 1 and the punch press 2, or if the lamellae 10 are produced in two or more tracks in the metal strip 3.

[0035] It is also possible, for example, for two jet cutting heads 8 to cut out the lamellae side by side on a correspondingly wide metal strip 3. This allows a very high output of the device to be achieved.

[0036] The described device and method are used to manufacture lamination stacks 14 for rotors and / or stators of electrical machines or generators. Lamination stacks for other applications can also be manufactured using the device and method. In this case, beam cutting processes other than laser cutting are also possible.

Claims

[1] Method for producing lamellae (10) for a lamella pack (14), in particular for electrical machines and generators, from a metal strip (3), wherein the lamella (10) is punched out of the metal strip (3) using at least one punching tool (13), characterized by , that the entire contour (9) of the lamella (10) except for connection points (11) to the metal strip (3) is produced by jet cutting, wherein the metal strip (3) remains stationary during the jet cutting, that subsequently the connection points (11) are cut by the punching tool (13) to remove the lamella (10) from the metal strip (3), and that the lamellae (10) are subsequently stacked to form the lamella pack (14). [2] Method according to claim 1, characterized by that the lamella (10) is held in the metal strip (3) by at least two connection points (11). [3] Method according to claim 1 or 2, characterized by, that the lamellae (10) are manufactured in a track of the metal strip (3). [4] Method according to claim 1 or 2, characterized by , that the lamellae are manufactured in at least two tracks of the metal strip (3). [5] Method according to any one of claims 1 to 4, characterized by , that a narrow band is used as the metal band (3). [6] Method according to any one of claims 1 to 4, characterized by , that a wideband is used as the metal band (3). [7] Device with at least one stamping press (2) having at least one stamping tool (13), in particular for carrying out the method according to one of claims 1 to 6, characterized by, that the device has at least one jet cutting unit (1) upstream of the punching press (2) with at least one jet cutting head (8), and that a packing unit (12) is upstream of the punching press (2) with which connecting elements (16) required to form the lamella pack (14) are applied to or inserted into the metal strip (3). [8] Device according to claim 7, characterized by , that a straightening device (6) is connected upstream of the beam cutting unit (1). [9] Device according to claim 7 or 8, characterized by , that a feed device (7) is connected upstream of the beam cutting unit (1). [10] Device according to any one of claims 7 to 9, characterized by , that a decoiler (5) is connected upstream of the beam cutting unit (1). [11] Device according to any one of claims 7 to 10, characterized by that the stamping press (2) has at least one stacking station (15) for stacking the lamellae (10). [12] Lamella (10) produced according to the method according to any one of claims 1 to 6, characterized by , that the contour (9) of the lamella (10) is produced by jet cutting. [13] Lamella pack (14) produced according to the method according to any one of claims 1 to 6, characterized by , that the contour (9) of the lamella (10) is produced by jet cutting.

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