Structural unit for an electric machine and method and tool system for producing such a structural unit

Abstract

The invention relates to a structural unit and to a method and a tool system for producing same for an electric machine, such as a rotor or more particularly a stator, having a lamination stack (1) put together from a plurality of sheet metal laminations layered one on top of the other in the direction of a longitudinal axis, which lamination stack is, in the circumferential direction, assembled from a plurality of stack segments (10) with lamination segments which are arranged in the circumferential direction and engage in one another by means of lateral holding structures. High precision of the structural unit combined with flexible adjustment of the production process to meet different requirements is provided in that the stack segments (10) forming the lamination stack (1) are structured in a layered manner in the same way from at least two different lamination segment groups A (2) of identically contoured A-lamination segments (20) and lamination segment groups B (3) of identically contoured B-lamination segments (30), wherein the A-lamination segments (20) differ from the B-lamination segments (30) in their holding structures in terms of their holding force in at least the radial direction in the plane of the sheet metal laminations.

Description

[0001] Assembly unit for an electrical machine and method and tool system for producing such an assembly unit

[0002] The invention relates to a structural unit for an electrical machine, such as a rotor or in particular a stator, with a lamination pack composed of a plurality of sheet metal laminations stacked on top of one another in the direction of a longitudinal axis, which is assembled in the circumferential direction from a plurality of pack segments with lamination segments arranged in the circumferential direction and interlocking by means of lateral holding structures.The invention further relates to a method and a tool system for producing such a structural unit, in which a punching arrangement for cutting sheet metal laminations to be stacked on top of one another to form a lamination pack is present in a tool arrangement of a production plant, wherein the punching arrangement has a plurality of cutting stations with cutting units for cutting the sheet metal laminations into lamination segments that can be dismantled and joined together circumferentially using lateral holding structures and reassembled after dismantling, and of required further cutting sections of the sheet metal laminations, and furthermore a stacking device controlled by a control device is present for forming the lamination pack from stacked sheet metal laminations, which is composed of pack segments in the circumferential direction. The pack segments of the lamination pack can be pulled apart for further processing.

[0003] A structural unit, a method, and a tool system of this type are disclosed in CA 2 758 405 C. In this known structural unit, a lamination stack for forming a ferromagnetic core, in particular a stator or rotor of an electric motor, is composed of circumferentially joined stack segments, each formed from lamination segments stacked one on top of the other in the direction of a longitudinal axis, with lamination segments having differently contoured holding structures being arranged within the stack segments. The stack segments joined to form the lamination stack are held together by means of the holding structures formed laterally on the lamination segments in the circumferential direction during the cutting process. These holding structures consist, on the one hand, of convex projections and, on the other hand, of concave recesses complementarily adapted thereto.Some of the holding structures are designed such that they are plastically deformed by means of a punch for exerting a holding force, while other holding structures are configured to pass through the punch. Among the pack segments joined together in a circle with respect to the lamination plane to form the lamination pack, there are pack segments with differently contoured holding structures. During production of the assembly, various lamination segments with corresponding holding structures are cut in a tool system using a cutting device and stacked in a stacking device to form pack segments. The pack segments are joined together in a linear arrangement with their complementary holding structures. Some of the joined holding structures are plastically deformed by means of the punch and finally the linear arrangement of the pack segments is joined together to form the annular lamination pack.The stack segments arranged at the ends of the lamination stack have a different structure with regard to the holding structures of the stacked lamination segments than the stack segments arranged between them. EP 0 833 427 B1 also shows a structural unit, in particular a stator core for a rotating electrical machine, consisting of sheet metal laminations stacked to form a lamination stack, which are composed of lamination segments with lateral holding structures in a ring shape. Here, too, lamination segments are first cut and stacked in a tool system, and the stack segments thus formed are joined together. In one embodiment, lamination segments provided with different holding structures can also be present within the stack segments. With such a structure, it is difficult to reliably ensure a high level of precision of the structural unit.

[0004] DE 10 2017 201 178 A1 presents a structural unit for an electrical machine and a method for its production, in which individual lamination segments are joined together by means of lateral holding structures to form an annular lamination, and the laminations are stacked to form a lamination pack. The lamination pack thus formed is then separated into its individual pack segments as a still unwound stator arrangement. The holding structures arranged laterally in the circumferential direction also consist of a tongue and groove connection, and the length of the projection and, if applicable, a bracing perpendicular to the surface plane of the individual laminations are selected such that after the individual lamination segments have been punched, they can be returned to the annular shape of the laminations, so that when the lamination pack or stator arrangement is constructed by stacking, the individual lamination segments are held together.This allows the thus formed stator assembly, provided with tooth tips, to be transported to a winding tool. The unwound stator assembly can be separated into its individual stack segments, in particular by applying a radial force to wind them. Subsequently, the individual stack segments can be reassembled into the lamination stack or stator assembly using a joining tool, applying a radial force directed toward each other. The completely cut laminations contribute to the high precision of the assembly; however, the joining and separating processes can have a detrimental effect on the joining forces.

[0005] EP 2 356 734 B2 shows an electric motor with a structural unit of a stator, which also has a lamination pack assembled from several pack segments with lateral holding structures.

[0006] EP 0 871 282 A1 shows lamination packs made of sheet metal laminations which are formed from lamination segments which are integrally connected to one another.

[0007] CN 104874756 B, CN 107008962 A and CN 108262519 B show cutting methods and cutting devices for slats.

[0008] As can be seen from the aforementioned publications, numerous topologies, geometries, and manufacturing processes for electrical machines are known. Depending on the application, the requirements for torque, power, noise generation, torque fluctuations, cogging torque, and material use vary considerably. Noise generation, weight, and efficiency of the drive are considered the most important performance indicators. Influencing factors include stator roundness, current intensity, resistance, system impedance, copper fill factor, number of poles, air gap between stator and rotor, length of the active parts (stator, rotor), iron factor, and lamination thickness. Maximizing electrical conductivity through a high copper fill factor (and thus high power density) and minimizing the air gap are particularly important here (see also Fräger, C., Amrhein, W. Handbook of Small Electrical Drives).Volume 2: System Components, Design. 5th edition 2021; VDI, 2015. Rotating Electrical Machines. Part 2-1: Standard Methods for Determining Losses and Efficiency from Tests. The underlying winding technology also plays a major role, as it significantly influences the performance indicators. Plug-in windings generally offer the highest copper fill factor, but are limited in scaling, and the manufacturing equipment is comparatively expensive. Other techniques include coil winding and needle winding, which are available in various forms (straight slot, oblique slot, individual teeth (either completely separated individual teeth or as so-called pre-cut, i.e., not completely separated, but only partially cut stator teeth), and full cut).

[0009] To reduce eddy currents in the iron core, it is manufactured from individual laminations. The individual laminations are held together by so-called interlocking clips, i.e., embossed surfaces of the laminations. Techniques for connecting lamination planes are described, among others, in DE 10 2012 224 153 A1 and in Liu, L.-H. and Liu L.-C. (2017). Analysis of interlocking performances on non-oriented electrical steels. AIP Advances 8, 056605 (2018).

[0010] The full-cut method has the fundamental advantage that the lamination stack or the stator formed from it forms a (practically) perfect circle, which in turn has a positive effect on the air gap and torque ripple. However, the full cut has the major disadvantage that the stator teeth are difficult to access for the winding overhang, and therefore the important copper fill factor does not reach the level of a plug-in winding or the winding of a segmented stator. The segmented stator therefore offers a good alternative. However, one difficulty lies in reuniting the individual stack segments formed by the stacked, segmented laminations or the individual stator teeth formed by them to form as round a circle as possible after winding is complete, in order to achieve a small air gap and low torque ripple.If the entire segmentation is performed without maintaining the punching sequence of the stator teeth, it is almost impossible to create a perfectly round circle. Furthermore, an additional welding process is usually necessary to reconnect the individual stator teeth. With so-called pre-cut technology, pre-punching is performed, and later in the process, the teeth are separated while maintaining the sequence. After winding, they are reassembled in the correct order (in practice, pre-cut technology is also used without maintaining the sequence, at the expense of poorer torque ripple and possibly with a larger air gap). Complete punching through the lamination segments or stator teeth and later joining the stator teeth is also possible while maintaining the sequence.For this purpose, positive and non-positive connections are available, as also demonstrated in the aforementioned publications. However, it is difficult to reliably maintain the positive and non-positive connection, especially with different sheet stacks, especially with different heights.

[0011] The present invention is based on the object of providing a structural unit for an electrical machine as well as a method and a tool system for producing such a unit, with which the cohesion of package segments in a lamination package can be maintained as precisely and reliably as possible.

[0012] This object is achieved in a structural unit having the features of claim 1, in a method for its production having the features of claim 5 and in a tool system having the features of claim 11.

[0013] In the structural unit, the invention provides that the stack segments forming the lamination pack are constructed in a layered manner from at least two different lamination segment groups A of identically contoured A lamination segments and lamination segment groups B of identically contoured B lamination segments, wherein the A lamination segments differ from the B lamination segments in their holding structures with regard to their holding force in at least the radial direction in the plane of the laminations. In particular, it can be provided that the holding force of the B lamination segments is practically zero. With these measures, a holding force or withdrawal and joining force in the lamination pack or the stator formed therefrom can be reliably specified and controlled.

[0014] The method provides that a sheet metal web is fed to a tool arrangement, from which sheet metal web A-sheet metal laminations with circumferentially joined A-lamination segments and B-sheet metal laminations with circumferentially joined B-lamination segments are cut out, wherein lateral holding structures of the A-lamination segments differ from lateral holding structures of the B-lamination segments in their holding force, and A-sheet metal laminations and B-sheet metal laminations are automatically layered on top of one another in a sequence predetermined by a control device in the direction of a longitudinal axis to form a lamination pack, so that the radial holding force between the pack segments layered from the A-lamination segments and B-lamination segments lies in a predetermined holding force range.

[0015] In the construction of the tool system according to the invention, it is provided that two different cutting stations are provided for cutting the lamella segments, one of which is designed for cutting A-lamella segments whose lateral interlocking holding structures are designed to exert radial holding forces, and the other cutting station is designed for cutting B-lamella segments whose lateral interlocking holding structures are designed to exert lower holding forces than the holding structures of the A-lamella segments, up to practically no holding forces, and that the stacking device is designed for arranging a number of A-laminated lamellas composed of A-laminated segments and a number of B-laminated lamellas composed of B-laminated segments within a lamella pack according to the specification of the control device,The number of A-sheet laminations and the number of B-sheet laminations are determined by the control device based on a required holding force within a specified holding force range between the stack segments. The number of A-sheet laminations and, if necessary, also of B-sheet laminations is readjusted or adjusted if the holding force between the stack segments is not (or no longer) within the specified holding force range.

[0016] By means of the tool system thus set up and the method for manufacturing the component, a manufacturing process for the component that is easily adaptable to different requirements and reliably controllable is achieved.

[0017] An advantageous embodiment of the structural unit is that the A-lamella segments are each provided on one side in the direction of rotation with at least one undercut groove-like holding recess and on the other side in the direction of rotation with a complementary holding extension adapted to it and insertable with a coordinated holding force, and that the B-lamella segments are each provided on one side in the direction of rotation with at least one undercut groove-like shaped recess and on the other side in the direction of rotation with a shaped extension adapted to it and insertable (practically) without any holding force.

[0018] Further advantages of the assembly arise from the fact that the lamella segment groups A have at least two A lamella segments and the lamella segment groups B have at least two B lamella segments, and that each stack segment comprises at least two lamella segment groups A and at least two lamella segment groups B, with the lamella segment groups A and B alternating (in the same way) within the stack segments. An advantageous embodiment in particular consists in the fact that only two different lamella segments, namely A lamella segments and B lamella segments, are present within the stack segment.

[0019] One design variant consists, for example, in that within a package segment at least two lamella segment groups A relative to one another and / or at least two lamella segment groups B relative to one another and / or at least one lamella segment group A relative to at least one lamella segment group B have a different number of A lamella segments or B lamella segments.

[0020] An advantageous embodiment of the method involves measuring the holding force between the stack segments. Measuring the holding force can advantageously be used to check whether the holding force is or remains within the required holding force range during the manufacturing process, e.g., after a separation process for applying a winding and reassembly. The number of A-laminate segments exerting a holding force can be adjusted accordingly, in particular automatically by means of a control process via the control device. For example, in extreme cases, to maintain the specified holding force range, only A-laminates can be layered to form the laminate stack.

[0021] For an automatic process sequence, it is advantageously provided that if the holding force falls below the specified holding force range, the number of A-sheet laminations is increased and if the holding force range is exceeded, the number of A-sheet laminations is reduced to such an extent that the holding force lies within the specified holding force range, wherein the increased number of A-sheet laminations is compensated by omitting B-sheet laminations and the reduced number of A-sheet laminations is compensated by adding B-sheet laminations if necessary in order to maintain a specified stack height of the lamination package.Various advantageous design options for automatic process control, in particular for regulating the process sequence, consist in that the holding force is measured during the manufacturing process after completion of a lamination pack for each lamination pack or randomly after completion of several lamination packs for a lamination pack and that the measurement results are fed to the control device manually or (preferably) automatically.

[0022] Advantageous process variants consist in that the measurement of the holding force is carried out in the radial direction (perpendicular to the longitudinal axis) of the plate pack and includes a measurement of the separating force and / or a measurement of the joining force.

[0023] For the formation of the component and precise process control, it is also advantageous to measure the holding force after compression of the sheet metal laminations of the lamination pack and to measure the stack height and stack parallelism of the lamination pack before or after the measurement of the holding force or if the measurement of the holding force is not carried out.

[0024] The tool system is advantageously designed for automatic process control in such a way that a measuring device for measuring the holding force between the stack segments is integrated into the tool system, that the measured holding force is or can be fed to the control device by means of a transmission device and that the control device is designed such that if the measured holding force deviates from the predetermined holding force range, the number of A-sheet laminations in the lamination stack is increased or decreased such that the holding force lies within the predetermined holding force range, whereas the number of B-sheet laminations in the lamination stack, conversely, is correspondingly decreased or increased in order to maintain a predetermined stack height. The measured holding force within the process control can thus be easily used to regulate the process sequence while maintaining the holding force within the predetermined holding force range.With this tool system, different requirements, e.g. for different electrical machines, can be easily met with virtually no effort.

[0025] An advantageous embodiment of the tool system further consists in that the tool arrangement has a compressor unit for compressing the sheet metal laminations stacked on top of one another to form the lamination package, which compressor unit is arranged upstream of the measuring device, if present, for measuring the holding force in the process flow.

[0026] Furthermore, the tool system is advantageously designed in that the tool arrangement has a measuring arrangement, in particular assigned to the compressor unit, for measuring the stack height and / or the parallelism of the end faces of the plate pack.

[0027] A further advantageous embodiment of the tool system is that the measuring device for measuring the holding force has a withdrawal device and / or a joining device for measuring a separating force and / or joining force.

[0028] The subject matter of the invention further comprises a stator of a rotating electrical machine having a structural unit, wherein a stator tooth is formed on each stack segment and winding spaces with insertable or inserted windings are arranged between the stator teeth of adjacent stack segments.

[0029] The invention is explained in more detail below using exemplary embodiments with reference to the drawings. In the drawings: Fig. 1 shows a section of a lamination pack with two pack segments joined together in the circumferential direction, each of which is formed in the same way from two different lamination segment groups A and B stacked on top of one another in the direction of the longitudinal axis of the lamination pack, with A lamination segments and B lamination segments being identical within the group but different from group to group, in a perspective view, exploded in the longitudinal direction between the groups.

[0030] Fig. 2 shows two package segments pulled apart in the circumferential direction with slat segment groups A and B lying on top of each other in the longitudinal direction in a perspective view,

[0031] Fig. 3 shows the package segments according to Fig. 2 in their state assembled in the direction of rotation in a perspective view,

[0032] Fig. 4 a plan view of two A-lamella segments joined together in the circumferential direction with more closely marked holding structures of a geometry A with holding extension and holding recess,

[0033] Fig. 5 a plan view of two B-lamella segments joined together in the circumferential direction with a detailed description of their holding structures of a geometry B with mold extension and mold recess,

[0034] Fig. 6 a cutting unit for sheet metal lamellas with cutting elements for forming holding structures of the lamella segments in a perspective view,

[0035] Fig. 7 shows a further cutting unit for cutting further cutting contours of the sheet metal lamellas in a perspective view, Fig. 8 shows a punching tool structure with parts of a tool frame in a top view,

[0036] Fig. 9 is a schematic view of a tool arrangement of a tool system for producing a plate pack in plan view,

[0037] Fig. 10 is a schematic view of a production plant for the manufacture of lamination packs and

[0038] Fig. 11 a measuring device for measuring the holding force between the package segments of a lamination package and

[0039] Fig. 12A and 12B a measuring device for measuring the roundness of a lamination pack, in particular a stator.

[0040] Figs. 1 to 3 show a section of a lamination pack 1 with two pack segments 10 to illustrate the structural principle of a lamination pack in various perspective views. The lamination pack 1 forms, for example, the laminated core of a stator of a rotating electrical machine, such as an electric motor. The pack segments are assigned to individual stator teeth and, in this case, each have a radially inwardly directed stator tooth with a tooth tip and winding spaces 11 located between the stator teeth for accommodating a stator winding (not shown).In the area radially outward from the tooth tip, in this case the stator yoke, the stack segments 10 are joined together via retaining structures and can be separated from one another with a certain radially directed pull-off force in a plane perpendicular to the longitudinal axis of the lamination stack 1, in order to then apply the winding to the stator teeth as easily as possible. The stack segments 10 are then rejoined to form the lamination stack 1 or stator with a radially inward joining force, with the retaining structures being designed to exert sufficient holding force to ensure reliable operation of the electrical machine.

[0041] The stack segments 10 of the lamination pack 1 are, as clearly shown in Fig. 1, constructed from two lamination segment groups stacked one on top of the other in the direction of the longitudinal axis of the lamination pack 1, namely a lamination segment group A 2 , which is provided with holding structures that exert a specific holding force in the radial direction of the lamination pack 1, and a lamination segment group B 3 , which exerts practically no holding force or, compared to the lamination group A 2 , a significantly lower holding force (e.g., at most half or at most 60% or 80% of the holding force). The lamination segment groups A 2 and B 3 are stacked alternately on top of one another.

[0042] Depending on the holding force to be generated, each lamella segment group comprises several identical lamella segments, namely the lamella segment group A 2 comprises A lamella segments 20 which exert a holding force with their holding structures, and the lamella segment group B 3 comprises B lamella segments 30 which exert no or at most a significantly lower holding force (e.g. at most half or at most 60% or 80% of the holding force of the A lamella segments) with their holding structures.

[0043] In the embodiment shown in Fig. 1, facing the upper end face, there is first arranged an A-slat segment group A 2 with two A-slat segments 20, below which a slat segment group B 3 with six B-slat segments 30, and below this, alternately a slat segment group A 2 with two A-slat segments 20 and a slat segment group B 3 with six B-slat segments 30 as well as another slat segment group A 2 with two A-slat segments 20 and a slat segment group B 3 with six B-slat segments 30 and finally, towards the lower end face, another slat segment group A 2 with two A-slat segments 20. The number of slat segment groups A 2 and the number of A-slat segments 20 arranged within the slat segment group A 2 are selected such that the holding force between the package segments 10 is within a specified holding force range.

[0044] The holding force can be predetermined by the design of the holding structures on the A-lamella segments 20 (and optionally the B-lamella segments 30) through measurement and / or simulation, but is advantageously measured within the production process using a measuring device (optionally additionally), as explained in more detail below. Depending on the holding force to be applied, the number of A-lamella segments 20 within the lamella segment group A 2 of the respective stack segments 10 and the number of lamella segment groups A 2 within the stack segments 10 can be varied in order to maintain the holding force between the stack segments 10 within the specified holding force range. The number of A-lamella segments 20 can remain the same or vary from lamella segment group A 2 to lamella segment group A 2 within a stack segment 10.

[0045] The structure of the pack segments 10 forming the lamination pack 1 with the lamination segment groups A 2 and B 3 stacked in the direction of the longitudinal axis of the lamination pack 1 is the same from pack segment 10 to pack segment 10, i.e. the pack segments 10 are constructed in the same way from lamination segment groups A 2 and B 3 with respective A lamination segments 20 and B lamination segments 30. By arranging more or fewer lamination segment groups B 3 and / or more or fewer B lamination segments 30, the stack height of the lamination pack 1 can be varied (without or without significant change in the holding force), so that a predetermined dimension of the lamination pack 1 or of a stator constructed from it can be precisely maintained. When constructing the plate pack 1, it may be advantageous if the plate pack 1 is closed on both of its end faces with plate segment groups A 2.It may also be advantageous to arrange at least one slat segment group A 2 in the central area to exert a holding force.

[0046] In Fig. 2, the two pack segments 10 shown in Fig. 1 are shown in a circumferentially expanded arrangement and compactly stacked on top of one another in the longitudinal direction with the lamella segment groups A 2 and B 3 . In Fig. 3, the two pack segments 10 shown in Fig. 2 are shown in a circumferentially assembled arrangement. The holding forces exerted between the pack segments 10 act both as pull-out forces (separation forces) when the pack segments 10 are pulled apart and as joining forces when the pack segments 10 are joined together to form the lamella pack 1.

[0047] Fig. 4 and 5 show exemplary holding structures of a geometry A of two joined A-lamella segments 20 (Fig. 4) and a geometry B of two joined B-lamella segments 30 (Fig. 5).

[0048] As Fig. 4 shows, the support structure of geometry A of the A-lamella segments

[0049] 20 on one side lying in the circumferential direction a holding projection 21 and on its side opposite in the circumferential direction a holding recess 22 complementary to the holding projection 21, so that two A-lamella segments 20 can be joined together in a fixing manner by means of their holding projection 21 and their holding recess 22. The holding recess 22 is designed as an undercut U-shaped groove, the groove opening of which, lying approximately in a radial plane perpendicular to the lamella plane, is narrower in or near the inlet area than its clear width towards the groove base, while the complementary holding projection

[0050] 21 has a correspondingly larger dimension towards its free end than its extension in the attachment area of ​​the A-lamella segment 20. This means that the entry area of ​​the holding recess 22 or the attachment area of ​​the holding extension 21 has a smaller extension X than the adjoining undercut groove area of ​​the holding recess 22 or the area of ​​the holding extension 21 lying towards the free end, so that when the holding extension 21 and the holding recess 22 are joined together, a clamping effect exerting the holding force results. Thus, the holding force can be precisely predetermined depending on the geometry and material, e.g., by simulation and / or (primarily) by measurement. Similar geometries resulting in a holding force are also possible (e.g., circular segment shape).

[0051] The B-lamella segments 30, on the other hand, are designed in such a way that when the mutually complementary holding elements of the holding structure are inserted, there is no holding force or at most a very low holding force, and in any case a significantly lower holding force (e.g. at most half as great) than with the A-lamella segments 20. This is achieved in that the B-lamella segments 30 have a groove-shaped shaped recess 32 pointing in the circumferential direction, e.g. also in a U-shape, no undercut, i.e. no narrowed opening area, and a shaped extension 31 complementary to this is not widened towards its free end compared to its attachment area on the B-lamella segment 30, but rather, for example, B. has mutually parallel or tapered flanks corresponding to the groove flanks of the mold recess 32. For example, the flanks of the mold recess 32 and the mold extension 31 can run parallel to each other over a width X, as shown in Fig. 5.In order to pull apart and join together as smoothly as possible and for manufacturing reasons of the stack segments 10, the holding extensions 21 and holding recesses 22 according to Fig. 4 and the shaped extensions 31 and shaped recesses 32 according to Fig. 5 are advantageously rounded in their opening area and in the transition area to the groove base. Furthermore, it is advantageous that the holding extensions 21 and shaped extensions 31 as well as the holding recesses 22 and shaped recesses 32 are similarly shaped, so that in the event of (slight) axial displacement of the laminations, as can occur during a winding process, assembling the stack segments is not made more difficult. To manufacture the lamination stacks 1, the individual laminations are manufactured in a beneficial procedure using a full cut, in which the required cutting contours for the air gap and the free spaces for the winding orThe tooth contour and, if applicable, further contours to be cut, as well as the dividing lines between the individual lamination segments of the sheet metal laminations, are completely cut in a suitably designed cutting unit, in particular in an automatic punching machine. In order to produce sheet metal laminations that correspond to the A-lamination segments 20 on the one hand and the B-lamination segments 30 on the other, two cutting units 4 provided with corresponding cutting geometries A and B are used in the respective tool arrangement 7 or production system 8 (see Figs. 9 and 10). One cutting unit 4 is shown as an example in Fig. 6. The cutting unit 4 comprises a cutting punch 40 for producing the holding structures and adjacent contour sections, as well as a cutting insert 41, a lifter 42, a transmission bolt 43, a transmission plate 44, and a compression spring 45.

[0052] The laminations with the ring-shaped joined A-lamination segments 20 as well as the laminations with the ring-shaped assembled B-lamination segments 30 result in a high level of precision of the laminations and the lamination pack 1 stacked from them due to the complete cutting of the laminations by means of the two correspondingly designed cutting units 4. In a stator constructed in this way, an extremely small gap is created when joining after the winding has been applied, which gap can be precisely maintained. This is important because external influences can cause the laminations to be axially offset from one another (e.g. due to winding tension). For example, in the case of pre-cuts that are only partially cut, i.e. not completely cut through (as is also common with conventional processes according to the state of the art), an undefined, partially protruding residual fracture structure remains which can no longer be joined without a gap, as a result of which the important roundness is no longer achieved or can be achieved.is significantly impaired. The holding extensions 21 or forming extensions 31 as extended wings are pressed flat in the relevant cutting unit 4 after the cutting process with the aid of the lifter 42. The lifter 42 is actuated via the spring force of the compression spring 45 (helical compression spring), the transfer plate 44 and the transfer bolt 43 and produces a flat sheet metal lamination or (in the case of a stator) stator lamination. Both processing steps, i.e. cutting and pressing back, take place in the same station, namely the relevant cutting unit 4, which advantageously eliminates the need for an additional leveling station for both cutting units 4 (for both geometry A and geometry B).

[0053] A key feature of the design of the lamination pack 1 formed from the A-lamination segments 20 and the B-lamination segments 30 is that the ratio of the number of A-lamination segments 20 to the number of B-lamination segments 30 is freely adjustable depending on the required holding force, in particular the radial pull-off force. The relevant control or regulation of the arrangement of the A-lamination segments 20 and B-lamination segments 30 during the design of the lamination pack 1 can be specified by the relevant design of a control device of the production plant.

[0054] A cutting device in which not the entire laminations are cut, but rather only the A-lamination segments 20 in one cutting station and the B-lamination segments 30 in a corresponding further cutting station, and the similarly stacked A-lamination segments 20 and B-lamination segments 30 are joined together as initially separate stack segments 10, e.g., after the winding has been applied, would also be possible in principle, but is considered less advantageous in this case due to disadvantages in terms of precision. It is particularly advantageous for use in the construction of a stator if the outer diameter of the lamination pack 1 remains constant throughout. This leads overall to a higher load-bearing capacity and better force distribution in a stator sleeve than with a discontinuous stator outer diameter. Cutouts for the aforementioned design of the lamination pack are therefore advantageously not located directly on the outer diameter of the lamination pack 1.In addition to the load-bearing capacity of a stator constructed in this way at the separation points, the continuous outer diameter is also advantageous for applying markings to the outer surface. If the cutouts for the separation points of the lamination segments are not located directly on the outer diameter, longer cutouts are possible to enable the holding extensions 21 or forming extensions 31 to be bent out in a way that is gentle on the material. In this case, the undercut is only located on the inner side of the relevant lamination segment. This means that an axial offset of the laminations does not result in radial thrusts that could have a negative impact on the outer diameter of the lamination pack 1 or the stator. Fig. 7 schematically shows a cutting punch 50 for the winding spaces 11 and a pre-cutting punch 51 for cutouts on the outer diameter. The cutouts are required to carry out the shearing process.

[0055] The cutting units 4 and further cutting units 5 are advantageously designed as punching tools in a structure with individual modules. Fig. 8 schematically shows a punching tool structure 6 with a tool frame having frame columns 60 and a base plate 61. Sheet metal to be cut or punched is fed via a belt inlet 62 to a module 63 designed for processing. The individual cutting modules serve primarily for handling. The modular design has not been common with regard to punch stacking to date. The immersion depth of the entire punching tool can be secured using spacer elements 64. A clamp 65 and sliding inserts 66, 67 represent a precise sliding mechanism for the modules. The tool arrangement shown in Fig. 9 has a cutting device with a catcher hole 70 and an index punch 71, as known per se. An air gap cutting station 72 is used for high-precision cutting of an air gap.The winding spaces and a pre-cut are then cut in a winding space and pre-cut cutting station 73. Catchers and lifters 74 are provided for further processing. Cutting stations 75 and 76, respectively, with the respective cutting units, are provided for cutting the A-lamella segments 20 and the B-lamella segments 30; these, in this case, constitute the essential main cutting processes of the invention.

[0056] Fig. 10 schematically shows a production plant 8 in which the production concept according to the invention is implemented. The production plant 8 is designed, for example, to build parts of an electrical machine with a rotor and stator and comprises an automatic punching machine 80, a rotor conveyor belt 81, a stator conveyor belt 82, a first robot unit 83 on the rotor conveyor belt 81 and a second robot unit 84 on the stator conveyor belt 82, a measuring and re-compaction unit 85 on the rotor conveyor belt 81, a further measuring and re-compaction unit 86 on the stator conveyor belt 82, a third robot unit 87 in the rotor line, labeling units 88 for the outer and end surfaces, a fourth robot unit 89 in the stator line and conveyor units 890, 891 for blisters in the rotor and stator lines, respectively. The degree of automation of the process line can be adapted depending on the number of pieces. Laser marking is optional.

[0057] The rotor conveyor belt 19 carries the rotor out from under the tool, and the stator conveyor belt 20 carries the stator out from under the tool. The robot units 21, 22 are preferably designed as SCARA robots, which place the parts from the respective conveyor belt onto the linear conveyor unit in an oriented manner. The measuring and recompaction units 85 and 86, respectively, compress the respective lamella packs of the rotor and stator, respectively, and measure their height and parallelism. The robot units 87, 89, also designed as SCARA robots, place the compressed lamella packs of the rotor and stator, respectively, into designated blisters or KLT containers, which are positioned via the respective conveyor units 890, 891.

[0058] In the punching machine 80, which is particularly designed as a high-performance punching machine, the individual sheet metal laminations are completely punched through. The holding forces between the stack segments 10 of the lamination stack 1 are measured at defined intervals during production in an assigned measuring station, which can be fed to this station automatically. The measurement results are fed directly into a control device of the production system 8. In this way, the radial holding forces or withdrawal and / or joining forces are controlled during production or can be controlled automatically. A stacking device with an integrated rotating unit within the tool arrangement 7 stacks the annular sheet metal laminations in a controlled or regulated arrangement to form the lamination stack 1. The lamination stacks 1 or the stators formed therefrom are transferred to the compressor unit 86 or (in the case of a rotor) 85 by means of the conveyor system.Using this measuring unit, the height of the lamination stack can be measured, allowing the number of laminations to be controlled during the manufacturing process. This allows individual laminations to be added or removed as needed. Additionally, the parallelism of the lamination stack 1 can be measured to ensure precise operation.

[0059] The integrated control of the number of A-plate segments 20 enables precise adjustment of the radial holding force. The measured holding force is compared with a specified holding force, and the number of A-plate segments 20 is automatically selected so that the holding force lies within the specified holding force range. The holding force is measured based, in particular, on the pull-out force (separation force) between the stack segments 10. The holding force between the stack segments 10 of the plate pack 1 can thus be adjusted within a fixed range, independent of tool wear, material strength, and / or the height of the plate pack 1. This contributes significantly to consistently high quality of the plate pack 1 and thus also of a stator or electrical machine constructed from it.

[0060] Fig. 11 shows the structure of a measuring device 9 for measuring the holding forces between the stack segments 10 of a lamination stack 1. The holding forces, in particular the separation forces, between two diametrically opposed pairs of stack segments 10 are measured simultaneously, and half the value of this separation force is assumed to be the holding force between two stack segments 10. This measurement result is fed to the control device for regulating the number of A-lamination segments 20. The number of B-lamination segments is adjusted accordingly to maintain a predetermined stack height of the lamination stack 1.

[0061] After measuring the separation force or holding force using the measuring device 9, the two halves of the lamination pack 1 are pressed together again and the entire lamination pack 1 is rotated by one pitch of the pack segments 10. The test is then repeated until all separation lines have been tested. The measured holding force can be determined based on statistical calculations (e.g., averaging, exclusion of excessive deviations from a mean value, or the like). Furthermore, the joining forces for joining the pack segments 10 can also be measured using the measuring device 9 when pressing the respective halves of the lamination pack 1 together. The integrated measurement of both the radial pull-off and / or joining forces as well as the stack height and parallelism of the lamination pack 1 enables precise compliance with the required holding forces, namely the pull-off and / or joining forces.

[0062] Fig. 11 schematically illustrates the structure of the measuring device 9 with a separating device. A first guide unit 90 has a guide rail 900 (e.g., in the form of a dovetail guide), and a second guide unit 93 has a further guide rail 930 (e.g., also a dovetail guide). A lower pair of clamping jaws 92 and an upper pair of clamping jaws 91 are guided on the guide rails 900 and 930, respectively. The second guide unit 93, the upper one in Fig. 11, is suspended in a floating manner via a suspension means 94. Between the upper pair of clamping jaws 91 and the lower pair of clamping jaws 92, one half of the plate pack 1 with the corresponding pack segments 10 is clamped, so that the two halves of the plate pack 1 are separated by exerting a tensile force on the upper pair of clamping jaws 91 via the second guide unit 93 with the suspension means 94 while measuring the pull-off force (separation force) between the two halves of the plate pack 1 orthe separation points between the respective pack segments 10 can be measured by means of the measuring device 9. Accordingly, the joining force for joining the two halves of the lamination pack 1 or the respective pack segments 10 can also be measured in the opposite direction to the pull-out direction.

[0063] Furthermore, the measurement of the outer diameter and roundness of the disk pack 1, as shown in Figs. 12A and 12B, can be made possible, for example, via a conical clamping ring 96 located in an inner mold of a separate measuring device 95, each with externally conical segments for centrally and roundly clamping a disk pack 1 or stator. For opening the segments, an eyelet, for example, is located in the ring or on the segments.

[0064] The presented inventive structure of the assembly for an electrical machine with the thus formed lamination pack, the presented method for producing the assembly and the production plant with the tool system for producing the assembly contribute significantly to increasing the precision of the assembly and the electrical machines equipped therewith and enable a flexible adaptation of the production process.

Claims

Claims 1. A structural unit for an electrical machine, such as a rotor or in particular a stator, comprising a lamination pack (1) composed of a plurality of laminated laminations stacked on top of one another in the direction of a longitudinal axis, which lamination pack is assembled in the circumferential direction from a plurality of pack segments (10) with lamination segments arranged in the circumferential direction and interlocking with one another by means of lateral holding structures, characterized in that the pack segments (10) forming the lamination pack (1) are constructed in the same way from at least two different lamination segment groups A (2) of identically contoured A-lamination segments (20) and lamination segment groups B (3) of identically contoured B-lamination segments (30), wherein the A-lamination segments (20) differ from the B-lamination segments (30) in their holding structures with regard to their holding force in at least the radial direction in the plane of the laminations.

2. Construction unit according to claim 1, characterized in that the A-lamella segments (20) are provided in the circumferential direction on one side with at least one undercut groove-like holding recess (22) and on the other side with at least one complementary holding extension (21) adapted thereto and insertable with a coordinated holding force, and that the B-lamella segments (30) are each provided on one side in the circumferential direction with at least one groove-like shaped recess (32) and on the other side with a shaped extension (31) adapted thereto and insertable without holding force. Assembly according to claim 1 or 2, characterized in that the lamella segment groups A (2) have at least two A-lamella segments (20) and the lamella segment groups B (3) have at least two B-lamella segments (30), and that each stack segment (10) comprises at least two lamella segment groups A (2) and at least two lamella segment groups B (3), wherein the lamella segment groups A (2) and lamella segment groups B (3) alternate in the same way within the stack segments (10).A structural unit according to one of the preceding claims, characterized in that within a package segment (10), at least two lamella segment groups A (2) relative to one another and / or at least two lamella segment groups B (3) relative to one another and / or at least one lamella segment group A (2) relative to at least one lamella segment group B (3) have a different number of A lamella segments (20) or B lamella segments (30). A method for producing a structural unit according to one of claims 1 to 4, wherein: - a sheet metal web is fed to a tool arrangement (7), - A-sheet metal lamellas with circumferentially joined A-lamella segments (20) and B-sheet metal lamellas with circumferentially joined B-lamella segments (30) are cut out of the sheet metal web, whereby lateral before holding structures of the A-lamella segments (20) differ from lateral holding structures of the B-lamella segments (30) in their holding force,- and A-laminates and B-laminates are automatically stacked one on top of the other in a sequence predetermined by a control device in the direction of a longitudinal axis to form a lamination stack (1), or B-laminates are completely omitted, so that the holding force between the stack segments (10) layered from the A-laminate segments (20) and B-laminate segments (30) or without B-laminate segments (30) lies within a predetermined holding force range. Method according to claim 5, characterized in that the holding force between the stack segments (10) is measured.Method according to claim 5 or 6, characterized in that if the predetermined holding force range is undershot, the number of A-sheet metal laminations is increased and if the holding force range is exceeded, the number of A-sheet metal laminations is reduced to such an extent that the holding force lies within the predetermined holding force range, wherein the increased number of A-sheet metal laminations is compensated by omitting B-sheet metal laminations and the reduced number of A-sheet metal laminations is compensated by adding B-sheet metal laminations in order to maintain a predetermined stack height of the lamination pack (1). Method according to claim 6 or 7, characterized in that the holding force is measured during the manufacturing process after completion of a lamination pack (1) for each lamination pack (1) or randomly after completion of several lamination packs (1) for a lamination pack (1). that the measurement results are fed to the control device manually or automatically.

9. Method according to one of claims 6 to 8, characterized in that the measurement of the holding force is carried out in the radial direction of the plate pack (1) and comprises a measurement of the separating force and / or a measurement of the joining force.

10. Method according to claim 8 or 9, characterized in that the measurement of the holding force takes place after a compression of the sheet metal laminations of the lamination pack (1) and that before or after the measurement of the holding force or if no measurement of the holding force is carried out, a measurement of the stack height and stack parallelism of the lamination pack (1) is carried out.

11. Tool system for producing a structural unit for an electrical machine, such as a stator or rotor, in particular according to claim 1, in which a punching arrangement for cutting sheet metal laminations to be stacked on top of one another to form a lamination stack (1) is provided in a tool arrangement (7) of a production plant (8), wherein the punching arrangement has a plurality of cutting stations (72, 73, 75, 76) with cutting units (4, 5) for cutting the sheet metal laminations into lamination segments that can be dismantled and joined together circumferentially with lateral holding structures and reassembled after dismantling, and of required further cutting sections of the sheet metal laminations, and furthermore a stacking device controlled by a control device is provided for forming the lamination stack (1) from stacked sheet metal laminations, which is composed of stack segments (10) in the circumferential direction, characterized in that for cutting the slat segments, two different cutting stations (75, 76) are provided, one of which (e.g. 75) is designed to cut A-slat segments (20) whose lateral interlocking holding structures are designed to exert radial holding forces, and the other cutting station (e.g.76) is designed for cutting B-laminate segments (30), the lateral interlocking holding structures of which are designed to exert lower holding forces than the holding structures of the A-laminate segments, down to practically no holding forces, and in that the stacking device is designed to arrange a number of A-laminate segments composed of A-laminate segments (20) and a number of B-laminate segments composed of B-laminate segments (30) within a laminate stack (1) as specified by the control device, wherein the number of A-laminate segments and the number of B-laminate segments is determined by the control device on the basis of a holding force to be maintained within a predetermined holding force range between the stack segments (10).Tool system according to claim 11, characterized in that a measuring device (9) for measuring the holding force between the package segments is integrated in the tool system, that the measured holding force is fed to the control device by means of a transmission device and that the control device is designed such that if the measured holding force deviates from the predetermined holding force range, the number of A-sheet metal laminations in the lamination package (10) is increased or decreased such that the holding force lies in the predetermined holding force range, whereas the number of B-sheet metal laminations in the lamination package (10) is, conversely, correspondingly decreased or increased.

13. Tool system according to claim 11 or 12, characterized in that the tool arrangement (7) has a compressor unit (85) for compressing the sheet metal laminations stacked on top of one another to form the lamination pack (10), which compressor unit is arranged upstream of the measuring device, if present, for measuring the holding force in the process sequence.

14. Tool system according to one of claims 11 to 13, characterized in that the tool arrangement (7) has a measuring arrangement, in particular assigned to the compressor unit (85), for measuring the stack height and / or the parallelism of the end faces of the lamination pack (10).

15. Tool system according to one of claims 12 to 14, characterized in that the measuring device (9) for measuring the holding force has a withdrawal device and / or a joining device for measuring a separating force and / or joining force.

16. Stator of a rotating electrical machine with a structural unit according to claim 1, wherein a stator tooth is formed on each stack segment (10) and winding spaces with insertable or inserted windings are arranged between the stator teeth of adjacent stack segments (10).

Images