Sheet metal for an electrical machine with integrated aluminum ring and method for its production

Abstract

Disclosed is a sheet (11, 11a, 11b, 14) for a laminated core (10, 13) of an electrical machine (1), which comprises an annular first section (15a, 15b) with recesses (16) for receiving a winding (12) of the electrical machine (1), an annular second section (17a, 17b) and an annular transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b). The first section (15a, 15b) is made of soft iron, the second section (17a, 17b) is made of aluminum, and the transition section (18a, 18b) changes its properties from soft iron to aluminum, starting at a boundary (D) with the first section (15a, 15b) and ending at a boundary (E) with the second section (17a, 17b).Furthermore, a laminated core (10, 13) with such laminates (11, 11a, 11b, 14), an electrical machine (1) with such a laminated core (10, 13), a vehicle (19) with such an electrical machine (2) and a method for producing such a laminated core (10, 13) are disclosed.

Description

TECHNICAL FIELD

[0001] The invention relates to a sheet for a laminated core of an electrical machine, wherein the sheet comprises an annular first section made of soft iron with recesses for receiving a winding of the electrical machine. Furthermore, the invention relates to a laminated core comprising a plurality of laminates of the type mentioned above stacked on top of one another. Furthermore, the invention relates to an electrical machine with a stator and a rotor rotatably arranged in the stator, wherein the stator comprises a stator laminated core of the type mentioned above and / or wherein the rotor comprises a rotor laminated core of the type mentioned above. Furthermore, the invention relates to a vehicle driven by such an electrical machine, and finally, the invention relates to a method for producing a sheet of the type mentioned above and a method for producing a laminated core of the type mentioned above. STATE OF THE ART

[0002] A sheet, a laminated core, an electrical machine, a vehicle, and methods of the above-mentioned type are generally known. A sheet, which is part of a laminated core, serves to accommodate windings or magnets and to guide a magnetic flux generated by the windings or magnets. For this reason, a sheet is made of soft iron. However, when it comes to assembling the electrical machine, the laminated core is usually installed in a stator housing, which is generally made of aluminum. The connection between the laminated core and the stator housing must fulfill a number of functions, one of which is the transmission of the torque generated by the electrical machine from the laminated core to the stator housing. For this reason, an interference fit is often provided between the laminated core and the stator housing.However, differences in temperature coefficient between aluminum and steel cause problems, as the interference fit weakens at higher temperatures. Accordingly, a compromise must be made between a desired temperature range, required torque transmission, and an acceptable stator housing thickness and face. DISCLOSURE OF THE INVENTION

[0003] Accordingly, it is an object of the invention to provide an improved sheet metal, an improved laminated core, an improved electric machine, an improved vehicle, an improved method for producing a sheet metal, and an improved method for producing a laminated core. In particular, a connection between a laminated core and a housing should provide good torque transmission over a wide temperature range while maintaining a low thickness and low weight of the housing.

[0004] The object of the invention is achieved by a sheet as disclosed in the introductory section, which further comprises: - an annular second section made of aluminum and - an annular transition section between the first section and the second section, which changes its properties from soft iron to aluminium starting at a boundary with the first section and ending at a boundary with the second section.

[0005] Furthermore, the inventive problem is solved by a laminated core comprising a plurality of laminated cores of the type mentioned above stacked one above the other.

[0006] Furthermore, the inventive object is achieved by an electrical machine having a stator and a rotor rotatably arranged in the stator, wherein the stator comprises a stator laminated core of the type mentioned above and / or wherein the rotor comprises a rotor laminated core of the type mentioned above.

[0007] In addition, the object of the invention is also achieved by a vehicle which is driven by an electric machine of the type mentioned above.

[0008] In one embodiment, the sheet or parts thereof can be manufactured using a metal printing process. In particular, the first section, the second section, and the transition section can be manufactured by printing and sintering a base material. The first section can be manufactured by printing and sintering a soft iron base material, the second section can be manufactured by printing and sintering an aluminum base material, and the transition section can be manufactured by printing and sintering i) a transition base material or ii) the soft iron base material and the aluminum base material. In case i), the transition section is printed using a purpose-specific transition base material, and in case ii), the transition section is printed with a mixture of the soft iron base material and the aluminum base material.

[0009] Accordingly, the object of the invention is also achieved by a method for producing a sheet for a laminated core of an electrical machine, which comprises the steps: - printing an annular first section with recesses for receiving a winding of the electrical machine with a soft iron base material, - Printing a ring-shaped second section with an aluminum base material and - printing an annular transition section between the first section and the second section i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section changes its properties from soft iron to aluminum starting at a boundary with the first section and ending at a boundary with the second section, and - Heating and sintering the sheet.

[0010] Here, heating and sintering of the sheet sections occur simultaneously. This means that all sections are printed first, and then all sections are heated and sintered simultaneously. The first section, the second section, and the transition section can be printed in any desired order. In particular, the first section can be printed first, then the transition section, and then the second section.

[0011] Accordingly, the object of the invention is achieved by a method for producing a sheet for a laminated core of an electrical machine, which comprises the steps: - printing an annular first section with recesses for receiving a winding of the electrical machine with a soft iron base material, - Heating and sintering of the first section, - Printing a ring-shaped second section with an aluminum base material, - printing an annular transition section between the first section and the second section i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section changes its properties from soft iron to aluminum starting at a boundary with the first section and ending at a boundary with the second section, and - Heating and sintering of the second section and the transition section.

[0012] Here, the heating and sintering of the sheet sections takes place in two steps. This means that in a first step, the first section is printed, then heated and sintered. In a second step, the second section and the transition section are printed, then heated and sintered. Accordingly, the first section is already solid when the second section and the transition section are printed.

[0013] Finally, the object of the invention can also be achieved by a method for producing a laminated core for an electrical machine, which comprises the steps: - stacking a plurality of sheets of the above-mentioned type or stacking a plurality of sheets produced by a method of the above-mentioned type, and - mutually joining the second sections of the plurality of sheets by heating them at least locally to the melting point of aluminum.

[0014] The proposed measures generally enable a better connection between a laminated core and a housing due to the smoother material transition provided by the transition section. Accordingly, a connection between a laminated core and a housing using the proposed laminations provides good torque transmission over a wide temperature range while maintaining a low thickness and low weight of the housing. Among other things, the proposed measures can also reduce the noise emanating from the electrical machine. In conclusion, the proposed measures, both in general and in detail, provide better properties and a better fit between the housing and the laminated core: - a more stable connection between the housing and the laminated core, - improved heat transfer from the laminated core to the housing, - Enabling higher housing tolerances, which reduces costs, - Enabling higher torque transmission between housing and sheet metal.

[0015] If the second sections of the multiple laminations are joined together by at least locally heating them to the melting point of aluminum, the stability of the laminated core can also be improved. The interconnected second sections essentially form a type of integrated housing. This simplifies the installation of the laminated core into an external housing, and a separate (external) housing can be omitted entirely. In this case, the actual laminations form an aluminum housing. In particular, the second sections of the multiple laminations can be joined together by laser welding.

[0016] The laminated core can generally a) be designed as a stator laminated core, - wherein in the case of an internal rotor machine, the transition section is arranged radially outwardly from the first section and the second section is arranged radially outwardly from the transition section, or - wherein, in the case of an external rotor machine, the transition section is arranged radially inwardly of the first section and the second section is arranged radially inwardly of the transition section, or b) be designed as a rotor core, - wherein, in the case of an internal rotor machine, the transition section is arranged radially inwardly of the first section and the second section is arranged radially inwardly of the transition section, or - wherein in the case of an external rotor machine, the transition section is arranged radially outwardly from the first section and the second section is arranged radially outwardly from the transition section.

[0017] Accordingly, the stator of the electric machine may comprise a stator laminated core according to case a), and / or the rotor of the electric machine may comprise a rotor laminated core according to case b).

[0018] It should be noted that while printing the sheets or parts of the sheets is advantageous, other production methods are also possible. In particular, the first section can be cut or punched from a metal sheet, and the second section and the transition section can be printed. This is similar to the aforementioned process, where the (printed) first section is already solid when the second section and the transition section are printed.

[0019] Further advantageous embodiments are disclosed in the claims and in the description as well as in the figures.

[0020] The transition section can generally be manufactured using a transition material that changes these properties continuously or stepwise within the transition section. In particular, the change can be based on varying the mixture of the transition material, which offers the possibility of continuously changing the material properties within the transition section. The mixture of the transition material can, for example, be continuously changed during a metal printing process. In another variant, several thinner rings, each having different material properties, can be manufactured within the transition section. In this way, a stepwise change in the material properties within the transition section can be provided. For this reason, the mixture of the transition material can, for example, be gradually changed during a metal printing process.It should be noted that the multiple thinner rings can flow into each other during heating and sintering, resulting in a gradual change in the material properties within the transition section.

[0021] In another embodiment, both the first section and the second section extend into the transition section, wherein the change in properties is based on a proportion of the first section and the second section in the transition section. For example, a pattern can be printed in the transition section using the soft iron base material and the aluminum base material, wherein the pattern provides the changes in the transition section on a macroscopic scale. The pattern can include circles, ovals, triangles, rectangles, trapezoids, and so on. The pattern can also flow into one another upon heating and sintering to provide a quasi-continuous change in material properties in the transition section.

[0022] The first section, the second section, and / or the transition section can advantageously be printed using a screen printing process. This allows the sheets to be produced very quickly. However, printing can also be done using a jet printer. Furthermore, both processes can be combined. For example, the first section and the second section can be printed using a metal screen printing process, while the transition section can be printed using a jet printing process. This allows the properties in the transition section to be varied very precisely.

[0023] In another advantageous embodiment, the heating and sintering of the first section and the transition section takes place by means of induction heating, and the heating and sintering of the second section takes place by heat transfer from the first section and transition section to the second section. Here, the magnetic conductivity of the soft iron is used to concentrate the heat on the first section and partially on the transition section, thus melting the soft iron particles in the first section and transition section separately. In contrast, the aluminum of the second section is not actively heated but melted by heat transfer from the first section and transition section to the second section.In this way, on the one hand, the soft iron with the comparatively high melting point and, on the other hand, the aluminum with the comparatively low melting point can be sintered very well without overheating the aluminum and without underheating the soft iron. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Now, the invention will be described in more detail below with reference to certain embodiments, but the invention is not limited to these. Fig. 1 shows a half-sectional view of an exemplary electric machine; Fig. 2 shows a front view of an exemplary stator lamination; Fig. 3 shows a detailed view of the stator lamination of Fig. 2; Fig. 4 shows an embodiment in which both the first section and the second section extend into the transition section; and Fig. Figure 5 shows a schematic view of an electric vehicle. DETAILED DESCRIPTION

[0025] In general, the same or similar parts are identified by the same / similar designations and reference symbols. The features disclosed in the description apply to parts with the same / similar designations or reference symbols. Information regarding orientation and relative position refers to the corresponding figure.

[0026] Fig. 1 shows a half-sectional view of an electrical machine 1 comprising a rotor shaft 2 and a rotor 3 mounted thereon, wherein the rotor shaft 2 is rotatably mounted about a rotor axis RA by (roller) bearings 4a, 4b. The electrical machine 1 further comprises a stator 5, a first bearing plate 6, a second bearing plate 7, and a stator housing 8 in which the stator 5 is arranged. The first bearing 4a is arranged in the first bearing plate 6, and the second bearing 4b is arranged in the second bearing plate 7. The first bearing plate 6, the second bearing plate 7, and the stator housing 8 together form a machine housing 9 or at least parts thereof.

[0027] The stator 5 comprises a stator lamination stack 10, which comprises a plurality of stator laminations 11 stacked one above the other along the stator axis or rotor axis RA. The stator 5 further comprises stator windings 12 or, alternatively, stator magnets arranged in the stator lamination stack 10. The rotor 3 likewise comprises a rotor lamination stack 13, which comprises a plurality of rotor laminations 14 stacked one above the other along the rotor axis RA. The rotor 3 further comprises rotor windings or rotor magnets arranged in the rotor lamination stack 13 (not shown).

[0028] Fig. 2 and Fig. 3 shows an exemplary stator lamination 11a. Fig. 2 shows a front view and Fig. 3 shows a detailed view of the stator lamination 11a. The stator lamination 11a comprises an inner edge B and an outer edge C and comprises an annular first section 15a made of soft iron with recesses 16 for receiving a stator winding 12. Furthermore, the stator lamination 11a comprises an annular second section 17a made of aluminum and an annular transition section 18a between the first section 15a and the second section 17a. The transition section 18a, beginning at a boundary D with the first section 15a and ending at a boundary E with the second section 17a, changes its properties from soft iron to aluminum.

[0029] In general, the first portion 15a, the second portion 17a, and the transition portion 18a can each be formed by printing and sintering a base material. For example, the first portion 15a can be formed by printing and sintering a soft iron base material, the second portion 17a can be formed by printing and sintering an aluminum base material, and the transition portion 18a can be formed by printing and sintering i) a transition base material or ii) the soft iron base material and the aluminum base material. In case i), the transition portion 18a is printed using a purpose-built transition base material, and in case ii), the transition portion 18a is printed using a mixture of the soft iron base material and the aluminum base material.

[0030] Printing can be performed, for example, using a screen printing process. This allows the stator laminations 11, 11a for a stator lamination stack 10 to be produced very quickly. However, printing can also be performed using a jet printer. Furthermore, both processes can be combined. For example, the first section 15a and the second section 17a can be printed using a metal screen printing process, while the transition section 18a can be printed using a jet printing process. In this way, the properties in the transition section 18a can be varied very precisely.

[0031] A method for producing a sheet 11, 11a may comprise the following steps: - printing the annular first section 15a with recesses 16 for receiving a winding 12 of the electrical machine 1 with a soft iron base material, - printing the annular second section 17a with an aluminum base material and - printing the annular transition section 18a between the first section 15a and the second section 17a i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section 18a changes its properties from soft iron to aluminum starting at a boundary D with the first section 15a and ending at a boundary E with the second section 17a, 17b, and - Heating and sintering the sheet 11, 11a.

[0032] Here, the heating and sintering of sections 15a, 17a, and 18a of the stator lamination 11, 11a occur simultaneously. This means that all sections 15a, 17a, and 18a are printed first, and then all sections 15a, 17a, and 18a are heated and sintered simultaneously. The first section 15a, the second section 17a, and the transition section 18a can be printed in any desired order. In particular, the first section 15a can be printed first, then the transition section 18a can be printed, and then the second section 17a can be printed.

[0033] An alternative method for producing a sheet 11, 11a may comprise the following steps: - printing the annular first section 15a with recesses 16 for receiving a winding 12 of the electrical machine 1 with a soft iron base material, - heating and sintering the first section 15a, - printing the annular second section 17a with an aluminum base material, - printing the annular transition section 18a between the first section 15a and the second section 17a i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section 18a changes its properties from soft iron to aluminum starting at a boundary D with the first section 15a and ending at a boundary E with the second section 17ab, and - Heating and sintering the second section 17a and the transition section 18a.

[0034] Here, the heating and sintering of sections 15a, 17a, and 18a of the stator lamination 11, 11a takes place in two steps. This means that in a first step, the first section 15a is printed and then heated and sintered, and in a second step, the second section 17a and the transition section 18a are printed and then heated and sintered. Accordingly, the first section 15a is already solid when the second section 17a and the transition section 18a are printed.

[0035] The transition section 18a can generally be manufactured with a transition material that continuously or gradually changes these properties in the transition section 18a. The change can in particular be based on varying a mixture of the transition material, i.e., based on varying soft iron particles and aluminum particles. The mixture of the transition material can, for example, be continuously changed during the metal printing process. In another variant, a plurality of thinner rings, each having different material properties, can be manufactured in the transition section 18a. In this way, a step-by-step change in the material properties in the transition section 18a can be provided. The mixture of the transition material can, for example, be gradually changed during the metal printing process for this reason.It should be noted that the multiple thinner rings may flow into each other during heating and sintering, thus causing a gradual change in the material properties within the transition section 18a.

[0036] In a preferred embodiment, the heating and sintering of the first section 15a and the transition section 18a can be achieved by induction heating, and the heating and sintering of the second section 17a can be achieved by heat transfer from the first section 15a and transition section 18a to the second section 17a. In this way, the magnetic conductivity of the soft iron particles is used to concentrate the heat on the first section 15a and the transition section 18a, thereby separately melting the soft iron particles in the first section 15a and transition section 18a. In contrast, the aluminum of the second section 17a is not actively heated, but rather melted by heat transfer from the first section 15a and transition section 18a to the second section 17a.In this way, on the one hand, the soft iron with the comparatively high melting point and, on the other hand, the aluminum with the comparatively low melting point can be sintered very well without overheating the aluminum and without underheating the soft iron.

[0037] It should be noted that while printing the sheets 11, 11a or parts thereof is advantageous, other production methods are also possible. In particular, the first section 15a can be cut or punched from a metal sheet, and the second section 17a and the transition section 18a can be printed.

[0038] In a further advantageous embodiment, a method for producing a stator laminated core 10 may comprise the following steps: - Stacking a plurality of stator laminations 11, 11a and - mutually joining the second sections 17a of the plurality of sheets 11, 11a by heating them at least locally to the melting point of aluminum.

[0039] In this way, the stability of the stator lamination stack 10 can be improved. The interconnected second sections 17a essentially form a type of integrated housing. This simplifies the installation of the stator lamination stack 10 into the stator housing 8, and a separate stator housing 8 can be omitted entirely. In this case, the actual stator laminations 11, 11a form an aluminum housing. In particular, the second sections 17a of the plurality of stator laminations 11, 11a can be interconnected by laser welding.

[0040] In case a) the laminated core 11, 11a can be designed as a stator laminated core 11, 11a, as in Fig. 1. In the case of an internal rotor machine, the transition section 18a may be arranged radially outward from the first section 15a and the second section 17a may be arranged radially outward from the transition section 18a, as shown in Fig. 2 and Fig. 3 is the case. In this case, the recesses 16 open towards the inner edge B of the stator lamination 11a, and the second section 17a is arranged at the outer edge C of the stator lamination 11a. In the case of an external rotor machine, the transition section 18a can also be arranged radially inward from the first section 15a and the second section 17a can be arranged radially inward from the transition section 18a. In this case, the recesses 16 open towards the outer edge C of the stator lamination 11a, and the second section 17a is arranged at the inner edge B of the stator lamination 11a.

[0041] In case b), the laminated core 11, 11a can be designed as a rotor laminated core 13. In the case of an internal rotor machine, the transition section 18a can be arranged radially inward from the first section 15a and the second section 17a can be arranged radially inward from the transition section 18a. In this case, the recesses 16 open towards the outer edge C of the rotor lamination 14, and the second section 17a is arranged at the inner edge B of the rotor lamination 14. In the case of an external rotor machine, the transition section 18a can be arranged radially outward from the first section 15a and the second section 17a can be arranged radially outward from the transition section 18a. In this case, the recesses 16 open towards the inner edge B of the rotor lamination 14, and the second section 17a is arranged at the outer edge C of the rotor lamination 14.

[0042] Thus, the stator 5 of the electrical machine 1 can comprise a stator laminated core 10 according to case a), and / or the rotor 3 of the electrical machine 1 can comprise a rotor laminated core 13 according to case b).

[0043] In the examples shown above, the transition section 18a was made with a (separate) transition material. However, the transition section 18b can also be formed by the first section 15b and the second section 17b, as shown in Fig. 4. Here, both the first section 15b and the second section 17b extend into the transition section 18b, with the change in properties being based on a proportion of the first section 15b and the second section 17b in the transition section 18b. For example, a pattern can be printed in the transition section 18b using the soft iron base material and the aluminum base material, with the pattern providing the changes in the transition section 18b on a macroscopic scale. The pattern can also flow into one another during heating and sintering to provide a quasi-continuous change in the material properties in the transition section 18b. In the example of Fig. 4, teeth of the first section 15b and the second section 17b extend into the transition section 18b and form it. However, other shapes are also possible. For example, the first section 15b can have holes in which aluminum of the second section 17b is arranged, and vice versa. By changing the size and / or density of the holes, the properties of the transition section 18b can be defined.

[0044] The proposed measures generally enable a better connection between a laminated core 10, 13 and a housing 9 due to the smoother material transition provided by the transition section 18a, 18b. A connection between a laminated core 10, 13 comprising the proposed laminations 11, 11a, 11b, 14 and a housing 9 provides the following: - a stable connection between the laminated core 10, 13 and the housing 9 and thus a good torque transmission over a high temperature range, - low thickness and low weight of the housing 9, - comparatively large tolerances for the laminated core 10, 13 and the housing 9, - improved heat transfer from the laminated core 10, 13 to the housing 9 and - reduced noise emission from the electrical machine 1.

[0045] Fig.Finally, Figure 5 shows an electric vehicle 19 with an electric machine 1 according to the preceding definition, which is intended to drive the electric vehicle 19. Specifically, the electric machine 1 is coupled to a transmission 20, side shafts 21, and finally to the wheels 22. The electric machine 1 can be intended to drive the electric vehicle 19 permanently in a fully electric vehicle or temporarily, e.g., in combination with an internal combustion engine, in a hybrid vehicle.

[0046] It should be noted that the invention is not limited to the embodiments disclosed hereinabove, but combinations of the various variants are possible. In practice, the electric machine 1 and the electric vehicle 19 may have more or fewer parts than shown in the figures. It is also noted that the electric machine 1 and the electric vehicle 19 or parts thereof are not necessarily drawn to scale in the figures. Furthermore, the description may include the subject matter of further independent inventions. It should also be noted that the use of a transmission 20 is not mandatory and that the electric vehicle 19 can be driven solely by the electric machine 1.

[0047] It should also be noted that the term "comprise" does not exclude other elements, and the use of the article "a" does not exclude the plural form. Furthermore, elements described in connection with different embodiments may be combined. It is also noted that reference signs in the claims should not be construed as limiting the scope of the claims. List of reference symbols 1 Electric machine 2 rotor shaft 3 Rotor 4a, 4b camp 5 Stator 6 first bearing plate 7 second bearing plate 8 Stator housing 9 Machine housing 10 laminated core (stator laminated core) 11, 11a, 11b sheet metal (stator sheet) 12 Stator winding 13 Laminated core (rotor laminated core) 14 Sheet (rotor sheet) 15a, 15b first section 16 recess 17a, 17b second section 18a, 18b transition section 19 vehicles 20 gearboxes 21 Side shaft 22 wheels RA axis (rotor axis / stator axis) B Inner edge of the ring structure C Outer edge of the ring structure D Border first section / transition section E Border second section / transition section

Claims

[1] Sheet (11, 11a, 11b, 14) for a laminated core (10, 13) of an electrical machine (1), comprising an annular first section (15a, 15b) made of soft iron with recesses (16) for receiving a winding (12) of the electrical machine (1), characterized by - an annular second section (17a, 17b) made of aluminum and - an annular transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b), which changes its properties from soft iron to aluminum starting at a boundary (D) with the first section (15a, 15b) and ending at a boundary (E) with the second section (17a, 17b). [2] Sheet metal (11, 11a, 11b, 14) according to claim 1, characterized in that the first section (15a, 15b), the second section (17a, 17b) and the transition section (18a, 18b) are each produced by printing and sintering a base material. [3] Sheet metal (11, 11a, 11b, 14) according to claim 1 or 2, characterized in that the transition section (18a, 18b) is made with a transition material which changes its properties continuously or stepwise in the transition section (18a, 18b). [4] Sheet (11, 11a, 11b, 14) according to one of claims 1 to 3, characterized in that the change is based on a variation of a mixture of the transition material. [5] Sheet metal (11, 11a, 11b, 14) according to one of claims 1 to 3, characterized in that the first section (15a, 15b) and the second section (17a, 17b) each extend into the transition section (18a, 18b), wherein the change in the properties is based on a proportion of the first section (15a, 15b) and the second section (17a, 17b) in the transition section (18a, 18b). [6] Laminated core (10, 13) comprising a plurality of laminated cores (11, 11a, 11b, 14) stacked one above the other according to one of claims 1 to 5. [7] Laminated core (11, 11a, 11b, 14) according to claim 6, characterized in that the laminated core (11, 11a, 11b, 14) a) is designed as a stator laminated core (10), - wherein, in the case of an internal rotor machine, the transition section (18a, 18b) is arranged radially outwardly from the first section (15a, 15b) and wherein the second section (17a, 17b) is arranged radially outwardly from the transition section (18a, 18b), or - wherein in the case of an external rotor machine, the transition section (18a, 18b) is arranged radially inwardly from the first section (15a, 15b) and wherein the second section (17a, 17b) is arranged radially inwardly from the transition section (18a, 18b), or b) is designed as a rotor core (13), - wherein, in the case of an internal rotor machine, the transition section (18a, 18b) is arranged radially inwardly of the first section (15a, 15b) and wherein the second section (17a, 17b) is arranged radially inwardly of the transition section (18a, 18b), or - wherein in the case of an external rotor machine, the transition section (18a, 18b) is arranged radially outwardly from the first section (15a, 15b) and wherein the second section (17a, 17b) is arranged radially outwardly from the transition section (18a, 18b). [8] Electrical machine (1) comprising a stator (5) and a rotor (3) which is rotatably arranged in the stator (5), characterized in that - the stator (5) comprises a stator core (10) according to case a) of claim 7 and / or - the rotor (3) comprises a rotor core (13) according to case b) of claim 7. [9] Vehicle (19) driven by an electric machine (1) according to claim 1. [10] Method for producing a sheet (11, 11a, 11b, 14) for a laminated core (10, 13) of an electrical machine (1), comprising the steps: - printing an annular first section (15a, 15b) with recesses (16) for receiving a winding (12) of the electrical machine (1) with a soft iron base material, - printing an annular second section (17a, 17b) with an aluminum base material and - printing an annular transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b) i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section (18a, 18b) changes its properties from soft iron to aluminum starting at a boundary (D) to the first section (15a, 15b) and ending at a boundary (E) to the second section (17a, 17b), and - Heating and sintering the sheet (11, 11a, 11b, 14). [11] Method for producing a sheet (11, 11a, 11b, 14) for a laminated core (10, 13) of an electrical machine (1), comprising the steps: - printing an annular first section (15a, 15b) with recesses (16) for receiving a winding (12) of the electrical machine (1) with a soft iron base material, - heating and sintering the first section (15a, 15b), - printing an annular second section (17a, 17b) with an aluminum base material, - printing an annular transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b) i) with a transition base material or ii) with the soft iron base material and the aluminum base material, wherein the transition section (18a, 18b) changes its properties from soft iron to aluminum starting at a boundary (D) to the first section (15a, 15b) and ending at a boundary (E) to the second section (17a, 17b), and - heating and sintering the second section (17a, 17b) and the transition section (18a, 18b). [12] Method according to claim 10 or 11, characterized in that the first section (15a, 15b), the second section (17a, 17b) and / or the transition section (18a, 18b) are printed by means of a screen printing process. [13] Method according to one of claims 10 to 12, characterized in that the heating and sintering of the first section (15a, 15b) and the transition section (18a, 18b) takes place by means of induction heating and the heating and sintering of the second section (17a, 17b) takes place by means of heat transfer from the first section (15a, 15b) and transition section (18a, 18b) to the second section (17a, 17b). [14] Method for producing a laminated core (10, 13) for an electrical machine (1), comprising the steps: - stacking a plurality of sheets (11, 11a, 11b, 14) according to one of claims 1 to 5 or stacking a plurality of sheets (11, 11a, 11b, 14) produced by a method according to one of claims 10 to 13, and - mutually joining the second sections (17a, 17b) of the plurality of sheets (11, 11a, 11b, 14) by heating them at least locally to the melting point of aluminum. [15] Method according to claim 14, characterized in that the second sections (17a, 17b) of the plurality of sheets (11, 11a, 11b, 14) are joined together by laser welding.

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