Levelling device for a pressing apparatus for simultaneously compressing a plurality of stacks of laminated cores for a rotor of an electric machine, and method for simultaneously producing a plurality of stacks of laminated cores

Abstract

The invention relates to a levelling device (1) for a pressing apparatus for simultaneously compressing a plurality of stacks (2, 3) of laminated cores (4, 5) for an electric machine, wherein the stacks (2, 3) can be hydraulically mounted on hydraulically communicating cylinder-piston units (6, 7) in such a way that, by the introduction of a pressing force onto one of the stacks (2, 3), the pressing force can be hydraulically tared by a movement of the pistons (9, 10) and a difference in height between the stacks (2, 3) can be levelled and the stacks (2) can be compressed with the same pressing force. The invention further relates to a pressing apparatus having such a levelling device (1). The invention also relates to a method for simultaneously producing a plurality of stacks (2, 3) of laminated cores (4, 5) for an electric machine by means of such a pressing apparatus.

Description

[0001] LEVELING DEVICE FOR A PRESSING DEVICE FOR SIMULTANEOUSLY COMPRESSING MULTIPLE STACKS OF TIN PACKS FOR A ROTOR OF AN ELECTRIC MACHINE AND METHOD FOR SIMULTANEOUSLY PRODUCING MULTIPLE STACKS OF TIN PACKS

[0002] The invention relates to a leveling device for a press for simultaneously compressing several stacks of laminated cores for an electric machine. The invention further relates to a press with such a leveling device. The invention also relates to a method for simultaneously producing several stacks of laminated cores for an electric machine using such a press.

[0003] WO 2021 115520 A1 discloses a injection mold for manufacturing a rotor with several axially stacked modules, each with a magnet carrier and a plurality of magnets attached thereto. The injection mold has at least two injection plates prepared for feeding plastic to achieve plastic injection molding of the magnets.

[0004] The invention is therefore based on the objective of proposing a leveling device, a pressing device and a method of the aforementioned type, which enable the simultaneous production of several stacks of laminated cores for a rotor of an electric machine in a structurally simple and cost-effective manner.

[0005] The problem is solved by the features of claim 1 and alternatively by the features of claim 9 or 10. Further advantageous and claimed embodiments are described in the respective dependent claims, the description, and the drawings.

[0006] Accordingly, a leveling device for a press for the simultaneous compression of several stacks of laminated cores for the rotor of an electric machine is proposed. The stacks are hydraulically supported on hydraulically communicating cylinder-piston units, so that by applying a pressing force to one of the stacks, this force can be hydraulically balanced by moving the pistons, thus leveling any height difference between the stacks and allowing both stacks to be compressed with the same pressing force.

[0007] In a structurally simple and cost-effective manner, differences in stack height caused by component tolerances during stacking of the laminated cores can be compensated for. Consequently, a single press can simultaneously compress multiple stacks of laminated cores for an electric machine rotor, each with the same pressing force.

[0008] Furthermore, the press device ensures a reliable seal for the simultaneous injection of plastic into the stacks, specifically for attaching magnets to the sheet metal bundles. This reliably prevents over-molding and plastic leakage.

[0009] In a particularly advantageous manner, the stacks can each be stored on a piston movable in the stacking direction of the hydraulically communicating hydraulic cylinder-piston units and can be moved in the stacking direction with the respective piston to level a height difference between the stacks.

[0010] In a further particularly preferred embodiment of the invention, the cylinder-piston units have annular pistons guided in annular cylinders, which define annular pressure chambers within these cylinders. These pressure chambers can be pressurized with hydraulic fluid and communicate with each other via a hydraulic connection. The annular design allows for a uniform pressure distribution within the cylinders and on the pistons. Furthermore, it enables easy adaptation to the installation conditions; in particular, additional components can be arranged in the spaces radially enclosed by the cylinder-piston units. Consequently, a very compact arrangement is also possible.

[0011] A particularly simple embodiment of the invention is achieved if the annular cylinders preferably each have a U-shaped cross-sectional profile, wherein the U-legs and the U-base connecting them define an annular pressure chamber, and this chamber is bounded at the open side of the U by the respective engaging annular piston. It is further advantageous if the annular cylinders preferably each radially enclose a central free space. This allows for centrally located free space within the cylinder-piston units for the arrangement of further components. Consequently, a very compact arrangement can be achieved.

[0012] Preferably, at least one component of a clamping device for central alignment and centering of the sheet metal packages of the respective stacks is arranged in the free space.

[0013] A further embodiment of the invention provides for a crossbeam spanning the diameter of each annular piston in the force flow between the stacks and the respective piston. This crossbeam is designed to receive and evenly distribute the forces introduced by each stack to the respective piston. In this way, a uniform force transmission from the stacks to the pistons via the crossbeams is achieved, regardless of the stack dimensions.

[0014] Preferably, the crossbeams with an annular bearing surface rest on the annular support surface of the respective piston. Preferably, the bearing surface completely covers the support surface of the respective piston.

[0015] It is also advantageous if the crossbeams preferably have a concave curvature on the inner surface facing the respective piston. This allows for greater stability and strength of the crossbeams when supporting the loads introduced from the stacks. Furthermore, this creates free installation space for arranging additional components, in particular a clamping device for aligning and centering the sheet metal stacks during their compression. A further optimized design with regard to stability, strength, and installation space can be achieved if the curvature preferably extends from the radially inner edge of the bearing surface of the respective crossbeam.

[0016] The problem according to the invention is also solved by a pressing device for simultaneously compressing several stacks of sheet metal packages for an electric machine, with a leveling device described above. This results in the advantages already described above.

[0017] Preferably, the pressing device includes pressure means for simultaneously compressing several stacks of sheet metal packages. Preferably, a pressure plate is provided as the pressure means. The pressure plate preferably has several injection openings for filling the stacks with plastic to fix several magnets within the sheet metal packages.

[0018] The problem according to the invention is further solved by a method for the simultaneous production of several stacks of sheet metal packages for an electric machine using a previously described pressing device. This achieves the advantages already mentioned above.

[0019] In a particularly advantageous way, the stacks are compressed simultaneously with the same pressing force in the pressing device and simultaneously filled with plastic for fastening magnets in the sheet metal stacks.

[0020] Further claimed features of the invention will become apparent from the following description and from the drawings, which further explain the present invention. The drawings show:

[0021] Figure 1 shows a perspective view of a leveling device according to the invention for a press for simultaneously compressing two stacks of sheet metal packages for an electric machine,

[0022] Figure 2 shows a cutaway view of a press device according to the invention for simultaneously compressing two stacks of sheet metal packages for an electric machine with the leveling device.

[0023] The figures show, by way of example, various views of a leveling device 1 and a pressing device according to the invention for simultaneously compressing preferably two stacks 2, 3 or sheet metal bundles 4, 5 for an electric machine. The method according to the invention is also illustrated by these figures.

[0024] The stacks 2, 3 and the laminated cores 4, 5 can be used for a rotor or a stator of the electric machine. The laminated cores 4, 5 consist of stacked and interconnected laminations, each with a central bore 45, 46.

[0025] The leveling device 1 shown in Figures 1 and 2 serves to compensate for a height difference between the stacks 2, 3 in a press device for the simultaneous compression of the stacks 2, 3 with the same pressing force, which is caused in particular by component tolerances of the stacked sheet metal packages 4, 5 or sheets.

[0026] The leveling device 1 comprises two hydraulic cylinder-piston units 6, 7, each assigned to a stack 2, 3, which communicate hydraulically with each other via a hydraulic connection 8 shown in Figures 1 and 2. In Figure 2, the hydraulic connection 8 is indicated schematically by dashed lines. The cylinder-piston units 6, 7 thus form a closed hydraulic system. They are arranged directly next to each other to save installation space. Each unit comprises annular pistons 9, 10, which are guided in annular cylinders 11, 12. Pressure chambers 13, 14 are defined by the pistons 9, 10 and the cylinders 11, 12, each as an annular space within the cylinders 11, 12.

[0027] The cylinders 11, 12 each have a U-shaped cross-sectional profile (Figures 1 and 2), with the U-legs 15, 16, 17, 18 extending radially and the connecting U-base 19, 20 defining the respective pressure chamber 13, 14 at the cylinder base. At the open end of the U-shaped cylinder 11, 12, the respective pressure chamber 13, 14 is closed off by the respective movable, engaging annular piston 9, 10.

[0028] The cylinders 11, 12 are each constructed in two parts, with a U-shaped base section 15, 16, 17, 18, 19, 20 and an annular cover 47, 48. The base section comprises the U-shaped legs 15, 16, 17, 18, which each form the radial cylinder side walls, and the connecting U-shaped base 19, 20, which each forms the respective cylinder base.

[0029] The ring-shaped covers 47, 48 each rest on the open side of the respective cylinder 11, 12 on the end face of the free end of the respective radially outer cylinder side wall 15, 17 (Figures 1 and 2) and are each attached to it by screws 49.

[0030] The pistons 9, 10 each protrude with their free ends from the open ends of the cylinders 11, 12. At their protruding ends, they are radially recessed on the outer diameter. The covers 47, 48 each project slightly radially inward beyond the radially outer cylinder sidewall 15, 17 and engage in the recessed area of ​​the respective piston 9, 10. In this way, the covers 47, 48 also form a stop for the respective piston 9, 10 at the open end of the cylinder 11, 12.

[0031] To prevent the pistons 9, 10 from rotating, a locking element 59, in particular a pin, is provided which engages radially in a circumferential manner on radially opposite projections 60, 61 on the respective cover 47, 48 and on the respective piston 9, 10.

[0032] A radial hydraulic connection 21, 22 is provided on each of the radially outer cylinder side walls 15, 17 of the cylinders 11, 12, to which the

[0033] Hydraulic connection 8 is connected to supply hydraulic fluid to the respective pressure chambers 13, 14. Hydraulic connection 8 is screwed to the respective hydraulic ports 21, 22 of the cylinders 11, 12 (Figure 1). For filling both cylinders 11, 12 with hydraulic fluid, the

[0034] Hydraulic medium connection 8 has a filling port 50 with shut-off valve.

[0035] The pistons 9, 10 each protrude with their free ends from the respective cylinders 11, 12 and form flat, annular support surfaces 23, 24 for supporting each stack 2, 3 of sheet metal packages 4, 5 (Figures 1 and 2). A cross member 25, 26 is provided in the force transmission path between the pistons 9, 10 and the respective stack 2, 3 (Figure 1). It serves to absorb and evenly distribute the forces introduced by the respective stack 2, 3 onto the respective pistons 9, 10.

[0036] The crossbeams 25, 26 each span the diameter of the pistons (9, 10) and cover the respective central free space 52, 53 enclosed radially inside by the cylinders 11, 12. They each rest with an annular bearing surface 27, 28 on the respective annular support surface 23, 24 of the respective piston 9, 10 and completely cover it. In this way, complete surface contact is achieved. On the side facing away from the pistons 9, 10, the crossbeams 25, 26 each form a flat support surface 29, 30 for supporting the stacks 2, 3.

[0037] Accordingly, the stacks 2, 3 are each supported on the pistons 9, 10 via the crossbeams 25, 26 and are floatingly mounted via these through the cylinder-piston units 6, 7.

[0038] The crossbeams 25, 26 each have a concave curvature 51 extending from the radially inner edge 62, 63 of the respective support surface 29, 30 on the inner surface facing the respective piston 9, 10. This provides the crossbeams 25, 26 with greater stability and strength when supporting the loads introduced from the stacks 2, 3. Furthermore, the curvature 51 creates additional free space for arranging further components adjacent to the spaces 52, 53.

[0039] The leveling device 1 is arranged in a press as shown in Figure 2, which has a pressure means 31 for simultaneously compressing the two stacks 2, 3 sheet metal packages 4, 5. The pressure means 31 is a pressure plate with a flat contact surface 32 for simultaneous contact with both stack ends 33, 34 and for simultaneously pressing them together.

[0040] Figure 2 shows the press with the stacks 2, 3, which are each arranged in the force flow between the pressing means 31 and the pistons 9, 10 of the communicating hydraulic cylinder-piston units 6, 7 of the leveling device 1, which are movable in the stacking direction. The movement of the pistons 9, 10 is indicated by double arrows. The stacks 2, 3 are shown here, by way of example, supported on the respective crossbeam 25, 26 by a thermal insulation plate 35, 36 and a transport plate 37, 38, and via these onto the pistons 9, 10, and are movable with them in the stacking direction. The movement of the pistons 9, 10 and the stacks 2, 3 in the stacking direction is indicated by double arrows. The thermal insulation plates 35, 36 serve to thermally insulate the stack 2, 3, which is heated during the manufacturing process.The transport plates 37, 38 make it particularly easy to transport and arrange the stacks 2, 3 between different production stations during manufacturing.

[0041] To simultaneously compress two stacks 2, 3 of sheet metal bundles 4, 5 with different stack heights for an electric machine, the press is activated (Figure 2). This causes the pressure elements 31, with the pressure plate, to move vertically downwards towards the stacks 2, 3 in the plane of the image with a predetermined pressing force until the pressure surface 32 rests on the stack end 33, 34 of the stack 2, 3 with the greater stack height H. As explained above, the greater stack height H is due to a slight height difference, particularly as a result of component tolerances in the stacked sheets or sheet metal bundles. In Figure 2, this is exemplified by stack 2 on the left in the plane of the image; that is, stack 3 on the right in the plane of the image has a smaller stack height.

[0042] The pressing force is transmitted via the stack 2, which has the greater stack height H, and the crossbeam 23 to the piston 9 of the first cylinder-piston unit 6, and the larger stack 2 moves vertically downwards in the plane of the image with the piston 9, as indicated by the arrows (Figures 1 and 2). This forces the hydraulic fluid present in the pressure chamber 13 of the cylinder 11 of the first cylinder-piston unit 6 out of the cylinder 11 via the hydraulic fluid connection 8 into the cylinder 12 of the second cylinder-piston unit 7, as indicated by the arrows (Figure 1).

[0043] Accordingly, the pressure chamber 14 of the second cylinder-piston unit 7 is pressurized with hydraulic fluid and the piston 10 and the stack 3, which has a smaller stack height and is supported by the traverse 26, are moved vertically upwards in the plane of the image, as indicated by arrows (Figures 1 and 2), until the stack end 32 rests against the contact surface 32 of the pressure plate 31 and the height difference between the stacks 2, 3 is equalized.

[0044] Conversely, if the second stack 3 in the image plane has a greater stack height H to the right than the first stack 2, the compensation of the stack height difference proceeds analogously in the opposite direction.

[0045] In this way, the leveling device 1 allows the pressing force between the stacks 2, 3 to be hydraulically tared via the hydraulically communicating cylinder-piston units 6, 7, similar to a scale, and any difference in stack height between the stacks 2, 3 can be hydraulically leveled by the movement of the pistons 9, 10. Consequently, in the pressing device, both stacks 2, 3, which are horizontally at the same height against the contact surface 32 of the pressure plate 31, can be compressed with the same pressing force.

[0046] Under high pressure, approximately 50 tons, both stacks 2, 3 are compressed simultaneously with the same pressure. This results in a high seal between the pressure means or pressure plate 31 and the respective stack ends 33, 34 of the two stacks 2, 3. This enables uniform injection of plastic through injection ports 39 on the pressure plate 29 under high pressure simultaneously into both stacks 2, 3 (Figure 2).

[0047] The plastic injection serves to fix magnets arranged in provided cavities in the sheet metal stacks 4, 5 of the stacks 2, 3.

[0048] Distribution channels (not shown) are provided for distributing the injected plastic in the stacks 2, 3. These channels are located at the stack ends 33, 34 and connect to the injection openings 39 on the pressure plate 31 during compression (Figure 2). Carrier plates 43, 44 arranged between the individual sheet stacks 4, 5 guide the plastic to the next sheet stack 4, 5.

[0049] Once the plastic injection is complete, the compression process is stopped. The pressure devices 31 then move up, and the system can level itself again. The stacks 2 and 3 can be removed from the press on the transport plates 37 and 38.

[0050] The annular cylinders 11, 12 each enclose a free space 52, 53 with their radially inner cylinder side walls 16, 18, forming a central hole in which components of a clamping device 54 for the central alignment and centering of the lamination stacks 4, 5 of the respective stacks 2, 3 are arranged (Figure 1). The respective free space 52, 53 is enlarged by the respective concave curvature 51 on the inner surface of the crossbeams 25, 26 resting on the support surfaces 23, 24 of the pistons 9, 10.

[0051] The clamping device 54 comprises a conical mandrel 55 and a collet 56, which, with two collet arms 57, 58, encompasses the mandrel 55 (Figure 2). The mandrel 55 and the collet 56 are arranged in the central bores 45, 46 of the lamination stacks 4, 5 of the stacks 2, 3. Before compression, to clamp the stacks 2, 3, the collet 56 is pulled vertically downwards in the plane of the image by the clamping device 54. This causes the collet arms 57, 58 to widen in a radially outward direction and align the lamination stacks 4, 5 with their central bores 45, 46 coaxially.

[0052] List of reference signs

[0053] 1 leveling device

[0054] 2 stacks

[0055] 3 stacks

[0056] 4 sheet metal package

[0057] 5 sheet metal package

[0058] 6-cylinder piston unit

[0059] 7-cylinder piston unit

[0060] 8 Hydraulic connection

[0061] 9 pistons

[0062] 10 pistons

[0063] 11 cylinders

[0064] 12 cylinders

[0065] 13 Printing room

[0066] 14 Printing room

[0067] 15 U-shaped legs, radially outer cylinder side wall

[0068] 16 U-shaped legs, radial inner cylinder side wall

[0069] 17 U-shaped legs, radially outer cylinder side wall

[0070] 18 U-shaped legs, radial inner cylinder side wall

[0071] 19 U-base, cylinder base

[0072] 20 U-base, cylinder base

[0073] 21 Hydraulic medium connection cylinder

[0074] 22 Hydraulic medium connection cylinder

[0075] 23 Support surface, piston

[0076] 24 Support surface, piston

[0077] 25 T reverse

[0078] 26 T reverse

[0079] 27 contact surfaces

[0080] 28 contact surfaces

[0081] 29 Support surface T reverse

[0082] 30 Support surface T reverse

[0083] 31 Contact material, contact plate

[0084] 32 Contact surface 33 Stack end

[0085] 34 Stack end

[0086] 35 Thermal insulation board

[0087] 36 Thermal insulation board

[0088] 37 Transport plate

[0089] 38 Transport plate

[0090] 39 injection ports

[0091] 40

[0092] 41

[0093] 42

[0094] 43 Carrier plate

[0095] 44 T carrier plate

[0096] 45 central bore

[0097] 46 central bore

[0098] 47 lids

[0099] 48 lids

[0100] 49 screw

[0101] 50 filling connection

[0102] 51 Curvature

[0103] 52 free space

[0104] 53 Free space

[0105] 54 Clamping device

[0106] 55 Spanndom

[0107] 56 Collet

[0108] 57 Pliers arm

[0109] 58 Pliers arm

[0110] 59 locking element

[0111] 60 bulge

[0112] 61 Bulge

[0113] 62 Rand

[0114] 63 Rand

Claims

Patent claims 1. Leveling device (1 ) for a press for simultaneously compressing several stacks (2, 3) of sheet metal packages (4, 5) for an electric machine, wherein the stacks (2, 3) are hydraulically supported on hydraulically communicating cylinder-piston units (6, 7) such that by applying a pressing force to one of the stacks (2, 3) they can be hydraulically balanced by a movement of the pistons (9, 10) and a height difference between the stacks (2, 3) can be leveled and the stacks (2, 3) can be compressed with the same pressing force.

2. Leveling device (1) according to claim 1, characterized in that the stacks (2, 3) can each be mounted on a piston (9, 10) movable in the stacking direction of the hydraulically communicating cylinder-piston units (6, 7) and can be moved with the respective piston (9, 10) in the stacking direction to level a height difference between the stacks (2, 3).

3. Leveling device (1 ) according to one of claims 1 or 2, characterized in that the cylinder-piston units (6, 7) have annular pistons (9, 10) which are guided in annular cylinders (11 , 12) and define annular pressure chambers (13, 14) in these, the latter being capable of being pressurized with hydraulic fluid and communicating with each other via a hydraulic fluid connection (8).

4. Leveling device (1 ) according to claim 3, characterized in that the annular cylinders (11 , 12) each have a U-shaped cross-sectional profile, wherein the respective U-legs (15, 16, 17, 18) and the U-base (19, 20) connecting them each define the respective pressure chamber (13, 14) and this is limited at the respective open U-side by the respective engaging annular piston (9, 10).

5. Leveling device (1 ) according to one of claims 3 or 4, characterized in that the annular cylinders (11 , 12) each radially enclose a central free space (52, 53).

6. Leveling device (1 ) according to claim 5, characterized in that at least one component of a clamping device (54) for central alignment and centering of the sheet metal packages (4, 5) of the respective stacks (2, 3) is arranged in the free space (52, 53).

7. Leveling device (1 ) according to one of claims 3 to 5, characterized in that in the force flow between the stacks (2, 3) and the respective annular piston (9, 10) a traverse (25, 26) spanning the diameter of the piston is arranged, which is provided for receiving and uniformly distributing the forces introduced by the respective stacks (2, 3) onto the respective piston (9, 10).

8. Leveling device (1 ) according to claim 7, characterized in that the crossbeams (25, 26) each have a concave curvature (51 ) on the inner surface facing the respective piston (9, 10).

9. Pressing device for simultaneously compressing several stacks (2, 3) of sheet metal packages (4, 5) for an electric machine, with a leveling device (1 ) according to one of the preceding claims.

10. Method for the simultaneous production of several stacks (2, 3) of sheet metal packages (4, 5) for an electric machine, with a press device according to claim 9.

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