Lamination stack having clamping piece composite

Abstract

The invention relates to a laminated core (1), the laminated core (1) having a plurality of sheets (3) which are arranged in a row with respect to one another in the axial direction (2) of the laminated core (1), in which case magnet grooves (4) are formed in the laminated core (1), and the magnet grooves (4) are each formed by receiving openings (5) which are formed in the sheets (3) and which are aligned with one another in the axial direction (2) of the laminated core (1). In this case, at least one magnet (6) is engaged in each magnet groove (4) by means of a clamping web (7) protruding into the magnet groove (4), at least one clamping web composite (8) consisting of at least two clamping webs (7) being formed in at least one of the magnet grooves (4), the clamping webs (7) lying against one another at least in the engaged state of the laminated core (1).

Description

Technical Field

[0001] The invention relates to a laminated core, wherein the laminated core has a plurality of plates arranged in a row in the axial direction of the laminated core, wherein magnet slots are implemented in the laminated core and are formed by receiving openings formed in the plates and aligned with each other in the axial direction of the laminated core. At least one magnet is engaged in each magnet slot by means of a clamping piece that projects into the magnet slot. Background Art

[0002] Electric machines are usually used as electric drives for motor vehicles, for example as synchronous motors. In electric machines, rotors and / or stators are usually formed with a laminated core, wherein a plurality of laminations arranged one behind the other in the axial direction are stacked in a group. The individual laminations are in the form of thin plates which are punched or processed in another way into the desired shape, for example a disk shape.

[0003] In order to be able to arrange the permanent magnets necessary for the motor or generator operation of the electric machine in the lamination stack, a plurality of receiving spaces are provided in the lamination stack. These receiving spaces are usually formed in such a way that corresponding receiving space recesses are formed (or designed) in each sheet of the lamination stack, for example by punching these recesses out together directly during the punching process. The individual sheets are then arranged one after the other in such a way that the receiving space recesses in the individual sheets are oriented in alignment with one another and thus form receiving spaces for receiving the permanent magnets.

[0004] There are many methods for reliably fixing the permanent magnet in the receiving space. For example, it is known to use fillers or adhesives to fix the permanent magnet in the receiving space, which is correspondingly achieved by gluing or by injection compression, which is also known as transfer molding. However, this is disadvantageous in terms of process expenditure and manufacturing costs due to the need for additional process steps. For example, additional process steps lead to additional expenditure when handling the lamination stack before the fixing process, because additional measures must be taken before fixing to prevent the permanent magnet from falling off. In addition, special requirements are placed on the shape of the sheet, which in turn limits the design of the sheet.

[0005] Alternatively, patent document DE 10 2011 078 054 A1 describes a laminated core, wherein clamping pieces for clampingly fixing permanent magnets are arranged on the long sides of the receiving space. The length and elasticity of the clamping pieces extending into the recess of the receiving space are selected so that the clamping pieces can clamp the permanent magnets in the receiving space. For this purpose, a spacing space is provided between two clamping pieces arranged adjacent to each other in the axial direction, so that the clamping pieces are elastically bent into the spacing space by pressure in the axial direction. In this way, the permanent magnet can be easily pushed into the receiving space and fixed there by means of the clamping pieces.

[0006] Furthermore, patent document DE 20 2009 007 544 U1 also describes a lamination stack for a rotor of an electric motor, wherein the single plates stacked on one another form a receiving space for receiving a permanent magnet. For this purpose, each single plate has a number of notches corresponding to the number of receiving spaces, wherein inwardly directed clamping plates are again formed on the narrow sides of these notches. In the lamination stack, the single plates stacked on one another in other respects are twisted relative to one another in such a way that two clamping plates are prevented from directly abutting against one another in the receiving space.

[0007] However, the above-mentioned solution is disadvantageous in the context of the fact that, due to the current general efficiency requirements for electric motors, smaller plate thicknesses are increasingly being used for the plates or single plates, since smaller plate thicknesses lead to a reduction in eddy current losses. At the same time, however, a reduction in plate thickness also leads to a reduction in the holding effect of the clamping plate. However, since the geometry of the receiving space for the permanent magnets cannot be freely adjusted for electromagnetic reasons, the loss of holding force must be taken into account, in part, during production, especially under difficult design conditions.

[0008] In order to solve this problem, it is known from the prior art to use preformed clamping discs and to use a larger number of clamping discs per magnet slot.

[0009] Regarding preformed clamping sheets, patent document DE 10 2017 218 408 A1 describes a corresponding rotor core of an electric machine, wherein each permanent magnet inserted into the receiving space of the lamination stack is fixed in a form-fitting and friction-fitting manner, in that each individual sheet in the mutually stacked sheets of the rotor core is equipped with a corresponding clamping sheet. These clamping sheets are arranged at intervals from each other and therefore do not directly abut against each other. In addition, the clamping sheet has a holding section consisting of a bend. Thus, the holding section extends substantially parallel to the insertion direction of the permanent magnet, and the insertion direction here coincides with the longitudinal direction of the receiving space. In order to prevent possible damage to the magnet when inserting the permanent magnet, the holding section spaced apart from the edge of the concave cavity also has a protruding portion protruding in the direction of the concave cavity and therefore transverse to the longitudinal protrusion of the concave cavity, and the protruding portion is composed of an embossed contour. However, the real holding effect is based on the deformation of the unembossed flat area of ​​the holding section, which has a reduced cross-section compared to the embossed area of ​​the holding section, so as to achieve the bending of the holding section in this area. When the permanent magnet is inserted, this region deforms elastically.

[0010] However, these preformed clamping plates can only be produced with a certain minimum length of the clamping plate, but the bending of such long clamping plates results in a large plate length being bent into the plane that is important for eddy currents, i.e., in the axial direction of the laminated core, so that significant (or measurable) additional eddy current losses occur in the machine. In addition, the preform takes up a relatively large amount of space, which counteracts the guidance of the field lines by the designed connecting plates.

[0011] Increasing the number of clamping plates also leads to similar problems as with preformed plates. Due to the higher number, a greater plate length is bent into the planes that are important for eddy currents, resulting in measurable additional losses in the electric machine. Moreover, this measure is often almost ineffective, since the actual geometry of the clamping plates remains unchanged. In other words, if a loss of holding force occurs on one clamping plate, this can occur on all clamping plates, completely independent of the number of clamping plates. Summary of the invention

[0012] Against this background, the invention is based on the object of realizing a laminated core of the type mentioned in the introduction in such a way that a high holding force for magnets arranged in the laminated core is ensured even when using laminated cores with a small plate thickness.

[0013] According to the invention, this object is achieved in a laminated core of the type mentioned at the outset by forming at least one clamping core assembly consisting of at least two clamping cores in at least one of the magnet slots, wherein the clamping cores abut against one another at least in the joined state of the laminated core. Particularly expedient further developments of the invention are apparent from the description.

[0014] According to the invention, a lamination stack, in particular a lamination stack of a rotor of an electric machine, or an electric machine is provided, which in particular has a rotor with such a lamination stack. In this case, the lamination stack has a plurality of plates arranged in a row in the axial direction of the lamination stack. In addition, magnet slots (or magnet pockets) are implemented in the lamination stack (extending through the lamination stack in the axial direction), wherein these magnet slots are respectively formed by receiving openings formed in the plates and aligned with each other in the axial direction of the lamination stack. In addition, at least one magnet is connected, in particular frictionally and positively engaged (fügen, or connected) in each magnet slot by a clamping sheet extending into the magnet slot, wherein the clamping sheet is in particular formed on at least a part of the number of receiving openings. According to the invention, it is also provided that at least one clamping sheet complex consisting of at least two clamping sheets is formed in at least one magnet slot in the magnet slot, wherein these clamping sheets are in contact with each other at least in the engaged state of the lamination stack. Since the clamping pieces in the respective clamping piece composite are in contact with each other, a high holding force can be provided by the clamping piece for the magnets, in particular permanent magnets or hard magnets, arranged in the magnet grooves, despite the fact that the sheet metal and the clamping piece formed thereon are of a smaller sheet metal thickness or smaller than in the prior art. In this way, the magnets can be fixed in the magnet grooves even without further fixing them by gluing or injection compression, because the rigidity of the clamping piece composite is significantly increased, and thus the holding force that can be provided by the clamping piece composite is increased, in particular compared to the arrangement of individual clamping pieces that are not realized in the clamping piece composite.

[0015] In this case, the holding force provided by a clamping plate assembly or a plurality of clamping plate assemblies can advantageously be increased by a factor of four to ten compared to the design of individual clamping plates that do not rest against one another and have the same sheet thickness. This applies not only to designs of individual clamping plates with different geometries and / or designs of individual clamping plates with the same number as the clamping plate assembly, but also to designs in which the number of individual clamping plates is increased by a factor of one and a half compared to the design of the clamping plate assembly.

[0016] In principle, it can also be provided that a composite body section without clamping sheets is formed between the individual clamping sheets of at least one or each clamping sheet composite body, which are aligned axially with each other. This composite body section without clamping sheets can be formed in particular by plates without clamping sheets or plate segments without clamping sheets, which are arranged between plates with clamping sheets. The composite body section without clamping sheets should include one or more, preferably at most five, particularly preferably at most three plates without clamping sheets or plate segments without clamping sheets. Therefore, in the pre-engaged state of the laminated core, in which the magnets have not yet engaged in the magnet slots, the clamping sheets of the clamping sheet composite body or of each clamping sheet composite body are spaced apart from each other by the composite body section without clamping sheets and therefore do not yet abut against each other and accordingly extend in the plane of the plates with the corresponding clamping sheets and therefore perpendicularly to the engagement direction of the magnets in the magnet slots and / or perpendicularly to the axial direction of the laminated core, in which pre-engaged state the magnets have not yet engaged in the magnet slots. In the joined state of the laminated core, due to the at least partial deformation, in particular at least partial bending, of the clamping plates during the joining of the magnets in the magnet slots, the clamping plates of the or each clamping plate complex abut against each other at least transversely to the joining direction, so that a section of the complex without clamping plates is bridged at least in the abutment region of the or each clamping plate complex with the magnets. In this case, in the joined state, at least the section of the clamping plates of the clamping plate complex that is located in the abutment region with the magnets extends substantially in the joining direction of the magnets or in the axial direction of the laminated core.

[0017] In contrast, however, in a particularly advantageous further development of the invention it is preferably provided that the clamping plates of (each) clamping plate complex are formed on the plates that are directly successive in the axial direction of the laminated core. This can further increase the holding force that can be provided by the (corresponding) clamping plate complex, since the rigidity of the (corresponding) clamping plate complex is also further increased. Therefore, in this case, in the pre-engaged state of the laminated core, there are no complex sections without clamping plates between the clamping plates of the (corresponding) clamping plate complex. Therefore, the clamping plates of the clamping plate complex that are directly successive in this way already lie against each other in the pre-engaged state and extend in the plane of the plates with the corresponding clamping plates and therefore perpendicularly to the joining direction of the magnets in the magnet slots and / or perpendicularly to the axial direction of the laminated core. In the joined state of the laminated core, the clamping plates of the or each clamping plate composite lie against one another transversely to the joining direction and therefore, after at least partial deformation, in particular at least partial bending, of the clamping plates during the joining of the magnets into the magnet slots, still lie against one another transversely to the joining direction, so that in the joined state no composite sections without clamping plates are formed. In this case, in the joined state, at least the sections of the clamping plates of the clamping plate composite that are located in the region of contact with the magnets also extend substantially in the joining direction of the magnets or in the axial direction of the laminated core.

[0018] Furthermore, one embodiment of the invention is advantageous when the number of, in particular, directly successive, mutually contacting clamping plates of the (corresponding) clamping plate assembly is so large (selected) that the total sheet thickness of the clamping plate assembly including these clamping plates differs from the (nominal) gap thickness between the magnet slot, in particular the wall and the magnet by no more than the sheet thickness of the (single) clamping plate or the (single) plate. In this case, the gap thickness exists in particular in the case of one-sided contact of the magnet in the magnet slot. In this way, the required holding force and the (substantially) optimal contact of the (corresponding) clamping plate assembly with the magnet can be ensured and / or an overstretching of the clamping plates when the magnet is engaged in the magnet slot can be avoided. In this case, preferably, the total sheet thickness is less than the (nominal) gap thickness by no more than the sheet thickness of the (single) clamping plate and / or the (single) plate.

[0019] A further development of the invention which can also be considered advantageous is that the first clamping piece of the (corresponding) clamping piece complex at least in the direction of engagement of the magnet into the magnet slot has a different geometry than at least one clamping piece of the clamping piece complex (directly) following in the engagement direction. This can advantageously provide, for example, a section of the clamping piece leading in the engagement direction that covers the entire clamping piece complex and thus provides an optimal contact area of ​​the clamping piece complex with the magnet. For this purpose, the length of the first (or first) clamping piece leading in the engagement direction can, for example, be greater than the length of the other clamping pieces following in the engagement direction or transversely to the engagement direction, so that a shortening of the contact area of ​​the first clamping piece with the magnet, which shortening is caused during the deformation process by the mutual contact of the clamping pieces of the clamping piece complex.

[0020] Furthermore, an equally advantageous embodiment of the invention provides that the (individual) geometries of the (corresponding) clamping plates of the (corresponding) clamping plate complex, in particular those which follow one another in the direction of engagement of the magnets in the magnet slots, differ from one clamping plate to another. For this purpose, for example, a series of plates with clamping plates having different geometries can be stacked. The successive (sukzessive) different geometries advantageously enable adjustment of the mechanical properties, for example bending properties, such as (bending) stiffness, during and / or after the deformation of the clamping plate complex, in particular when the magnets are engaged in the magnet slots. This makes it possible, for example, to provide a clamping plate complex which is reinforced during deformation.

[0021] It is also advantageous if at least two of the (corresponding) clamping plates of the clamping plate assembly, in particular the clamping plates that are directly successive and abut one another, are preferably realized in the joined state of the laminated core and the magnet only partially overlapping. As a result, the individual plates with clamping plates can advantageously be produced by a (single) punching tool, which significantly reduces the production costs compared to designs in which the plates have clamping plates of different geometric shapes.

[0022] However, at least two, in particular directly successive, mutually abutting clamping plates of the (corresponding) clamping plate assembly can already be realized in a pre-joined state of the laminated core in which the magnets are not yet engaged in the magnet grooves, with only partial overlap.

[0023] It is also conceivable that a plurality of clamping plate combinations, which are formed successively in the axial direction of the laminated core, are arranged, preferably alternately, offset to one another, in particular on a (single) wall of the respective magnet slot.

[0024] However, in a similarly advantageous further development of the invention, it is contemplated that in at least one of the magnet slots having the clamping plate complexes at least one row of a plurality of clamping plate complexes is provided, wherein the clamping plate complexes of the respective row are arranged aligned with one another in the axial direction of the laminated core, thereby advantageously always providing a defined contact between the clamping plate complex and the magnets.

[0025] A further advantageous embodiment of the invention is that, in particular in the pre-engaged state of the lamination stack, in which the magnets have not yet engaged in the magnet grooves, an intermediate space is formed between each two clamping plate assemblies implemented in the respective row of clamping plate assemblies, in which intermediate space no clamping plates are formed on the plate surrounding the intermediate space. Thus, during the engagement of the magnets in the magnet grooves, the (corresponding) clamping plate assembly can at least partially be transferred into the intermediate space and at least partially occupy the intermediate space when the clamping plates are deformed, thereby forming a contact area with the magnets.

[0026] However, in particular in the above-described embodiment of the invention, it can also be generally considered advantageous if the intermediate space comprises such a large number of plates that the clamping plate assemblies that follow one another in the axial direction of the laminated core in the respective row do not overlap. This ensures that the highest possible clamping force is ensured and at the same time ensures that the magnets engage in the magnet slots without problems.

[0027] The embodiment of the invention is also advantageous if at least one clamping piece of the (corresponding) clamping piece assembly has a reinforcement profile, for example an embossing of the clamping piece. The holding force provided by the clamping pieces of the (corresponding) clamping piece assembly that are in contact with one another can thus be advantageously increased by the further increased rigidity achieved by the reinforcement profile. It is provided that the section of the clamping piece that has the reinforcement profile is the section of the clamping piece that is subjected to bending stresses, in particular due to the engagement of the magnet in the magnet slot. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention allows a large number of embodiments. In order to further illustrate their basic principles, one embodiment is shown in the accompanying drawings and described below. In the drawings:

[0029] Figure 1a , Figure 1b The lamination stack 1 is shown in a pre-engaged state;

[0030] Figure 2a The lamination stack 1 is shown in its joined state;

[0031] Figure 2b A detailed view of the clamping plate complex is shown. DETAILED DESCRIPTION

[0032] Figure 1a and Figure 1b The lamination stack 1 is shown in a pre-engaged state, in which the lamination stack 1 is not yet Figure 2a The magnet 6 shown is arranged in the magnet slot 4. Specifically, Figure 1b Show cutaway Figure 1aA sectional view of a laminated core 1 is shown, wherein the clamping plates 7 formed on the plates 3 and projecting into the magnet grooves 4 are not yet deformed in the shown pre-joined state and extend in the plane of the plates 3 with the respective clamping plates 7 and thus extend perpendicularly to the joining direction 10 of the magnets 6 in the magnet grooves 4 and / or perpendicularly to the axial direction 2 of the laminated core 1. In this case, two clamping plates 7 each form a clamping plate assembly 8, wherein the clamping plates 7 in the embodiment of the laminated core 1 still in the pre-joined state rest against one another and are in particular formed on the plates 3 that follow one another directly in the axial direction 2 of the laminated core 1.

[0033] Figure 2a The laminated core 1 is shown in its joined state, wherein the laminated core 1 and Figure 1a and Figure 1bAccording to the present invention, a plurality of plates 3 are arranged in a row in the axial direction 2 of the laminated core 1, and magnet slots 4 are realized in the laminated core 1. In this case, the magnet slots 4 themselves are formed in particular by receiving openings 5 ​​which are formed in the plates 3 and aligned with each other in the axial direction 2 of the laminated core 1, wherein the respective clamping plates 7 extend into the magnet slots 4 starting from the beginning of the receiving openings 5. Two magnets 6 are engaged in each magnet slot 4 by means of the clamping plates 7 which extend into the magnet slots 4, wherein the clamping plates 7 are deformed, in particular bent, by the engagement in the engagement direction 10. In this case, each two clamping plates 7 form a clamping plate complex 8, wherein the clamping plates 7 of the respective clamping plate complex 8 are formed on the plates 3 which are directly successive in the axial direction 2 of the laminated core 1 and also bear against each other. Due to the deformation, at least the section of the clamping plates 7 of the clamping plate assembly 8 which is located in the contact area 14 with the magnet 6 extends in the shown joined state essentially in the joining direction 10 of the magnet 6 or in the axial direction 2 of the laminated core 1. Here, the number of two clamping plates 7 of the respective clamping plate assembly 8 which are in contact with each other is so great that the total sheet metal thickness of the clamping plate assembly 8 including the respective two clamping plates 7 does not differ from the gap thickness 9 between the wall 13 of the magnet slot 4 and the magnet 6 by more than the sheet metal thickness of one of the clamping plates 7, wherein the sheet metal thickness of one clamping plate 7 is in particular smaller than the gap thickness 9. Furthermore, the clamping plate assembly 8 implemented in the shown magnet slot 4 is implemented in a row 11 of a plurality of clamping plate assembly 8, so that the clamping plate assembly 8 is arranged aligned with each other in the axial direction 2 of the laminated core 1. Here, between each two clamping disc composites 8 that are implemented and follow one another in the row 11, an intermediate space 12 is formed, in which no clamping discs 7 are formed on the metal sheets 3 that surround the intermediate space 12. Thus, during the engagement of the magnets 6 in the magnet slots 4, the respective clamping disc composite 8 can be at least partially transferred into the intermediate space 12 when the clamping discs 7 are deformed and at least partially occupy the intermediate space, thereby forming a contact area 14 with the magnets 6. The intermediate space 12 here includes such a large number of metal sheets 3 that the clamping disc composites 8 that follow one another in the axial direction 2 of the laminated core 1 in the respective row 11 do not overlap.

[0034] In addition, from Figure 2a and a detailed view showing the clamping plate complex 8 Figure 2b It can be seen in FIG. 8 that the two clamping plates 7 of the clamping plate assembly 8 which are formed on the plate 3 and lie against each other are realized only partially overlapping.

[0035] Reference numerals list

[0036] 1 lamination group

[0037] 2 Axial direction

[0038] 3 Plates

[0039] 4 magnet slots

[0040] 5Accommodate opening

[0041] 6 Magnets

[0042] 7 Clamping piece

[0043] 8 Clamping plate complex

[0044] 9 Gap Thickness

[0045] 10Joining direction

[0046] Row 11

[0047] 12 The Space Between

[0048] 13 Wall

[0049] 14 Attachment Area

Claims

1. A lamination stack (1), wherein: The laminated core (1) comprises a plurality of plates (3) arranged in a row along the axial direction (2) of the laminated core (1), wherein magnet grooves (4) are realized in the laminated core (1), and these magnet grooves (4) are respectively formed by receiving openings (5) molded in the plates (3) and aligned with each other along the axial direction (2) of the laminated core (1), wherein at least one magnet (6) is engaged in each magnet groove (4) by a clamping plate (7) extending into the magnet groove (4), characterized in that at least one clamping plate complex (8) consisting of at least two clamping plates (7) is formed in at least one magnet groove in the magnet groove (4), wherein these clamping plates (7) are in contact with each other at least in the engaged state of the laminated core (1).

2. The lamination stack (1) according to claim 1, characterized in that The clamping plates (7) of the clamping plate assembly (8) are formed on the plates (3) which directly follow one another in the axial direction (2) of the laminated core (1).

3. The lamination stack (1) according to claim 1 or 2, characterized in that: The number of clamping plates (7) abutting against each other of the clamping plate complex (8) is so great that the total sheet thickness of the clamping plate complex (8) including these clamping plates (7) differs from the gap thickness (9) between the magnet slot (4) and the magnet (6) by no more than the sheet thickness of one clamping plate (7).

4. The laminated core (1) according to at least one of the preceding claims, characterized in that The clamping piece (7) leading at least in the joining direction (10) of the magnet (6) into the magnet groove (4) of the clamping piece complex (8) has a different geometry than at least one clamping piece (7) following in the joining direction (10) of the clamping piece complex (8).

5. The laminated core (1) according to at least one of the preceding claims, characterized in that The geometry of successive clamping plates (7) of the clamping plate assembly (8) differs from one clamping plate (7) to another.

6. The laminated core (1) according to at least one of the preceding claims, characterized in that At least two of the clamping plates (7) of the clamping plate assembly (8) that abut against one another are realized in such a way that they only partially overlap.

7. The laminated core (1) according to at least one of the preceding claims, characterized in that At least one row (11) of a plurality of clamping plate complexes (8) is realized in at least one of the magnet slots (4) having clamping plate complexes (8), wherein the clamping plate complexes (8) of the respective row (11) are arranged aligned with one another in the axial direction (2) of the laminated core (1).

8. The laminated core (1) according to at least one of the preceding claims, characterized in that Between each two successive clamping plate assemblies (8) realized in a corresponding row (11) of clamping plate assemblies (8) an intermediate space (12) is formed, in which intermediate space no clamping plates (7) are formed on the plate (3) surrounding the intermediate space (12).

9. The laminated core (1) according to at least one of the preceding claims, characterized in that The intermediate space (12) comprises such a number of plates (3) that the clamping plate assemblies (8) which follow one another in the axial direction (2) of the laminated core (1) in the respective row (11) do not overlap.

10. The laminated core (1) according to at least one of the preceding claims, characterized in that At least one clamping plate (7) of the clamping plate assembly (8) has a reinforcing profile.

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