Lamination sheet for an electric machine with integrated aluminum ring and method of making the same

Abstract

A lamination sheet (11, 11a, 11b, 14) for a lamination stack (10, 13) of an electric machine (1) is disclosed, which comprises a ring shaped first section (15a, 15b) with recesses (16) for accommodating a winding (12) of the electric machine (1), a ring shaped second section (17a, 17b) and a ring shaped 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) starting at a border (D) to the first section (15a, 15b) and ending at a border (E) to the second section (17a, 17b) changes its characteristics from soft iron to aluminum. Further on, a lamination stack (10, 13) with such lamination sheets (11, 11a, 11b, 14), an electric machine (1) with such a lamination stack (10, 13), a vehicle (19) with such an electric machine (2) and a method of making such a lamination stack (10, 13) are disclosed.

Description

[0001] Lamination sheet for an electric machine with integrated aluminum ring and method of making the same

[0002] TECHNICAL FIELD

[0003] The invention relates to a lamination sheet for a lamination stack of an electric machine, wherein the lamination sheet comprises a ring shaped first section made of soft iron with recesses for accommodating a winding of the electric machine. Moreover, the invention relates to a lamination stack, which comprises a plurality of lamination sheets of the above kind being stacked over one another. Further on, the invention relates to an electric machine with a stator and a rotor being rotatably arranged in the stator, wherein the stator comprises a stator lamination stack of the above kind and / or wherein the rotor comprises a rotor lamination stack of the above kind. Additionally, the invention relates to a vehicle driven by such an electric machine, and finally the invention relates to a method of manufacturing a lamination sheet of the above kind and to a method of manufacturing a lamination stack of the above kind.

[0004] BACKGROUND ART

[0005] A lamination sheet, a lamination stack, an electric machine, a vehicle and methods of the above kinds are generally known. A lamination sheet, which is part of a lamination stack, is for accommodating windings or magnets and to guide a magnetic flux generated by said windings or magnets. For this reason, a lamination sheet is made of soft iron. However, when it comes to assembly of the electric machine, the lamination stack usually is mounted into a stator housing, which commonly is made of aluminum. The connection between the lamination stack and the stator housing has to fulfill a number of functions, inter alia transmission of the torque produced by the electric machine from the lamination stack to the stator housing. For this reason, often a press fit is provided between the lamination stack and the stator housing. However, different temperature coefficients between aluminum and steel lead to problems as the press fit gets weaker with higher temperatures. Accordingly, a tradeoff has to be made between a desired temperature range, a demanded torque transfer and an acceptable thickness and weight of the stator housing. DISCLOSURE OF INVENTION

[0006] Accordingly, an object of the invention is to provide an improved lamination sheet, an improved lamination stack, an improved electric machine, an improved vehicle, an improved method of making a lamination sheet and an improved method of making a lamination stack. In particular, a connection between a lamination stack and a housing shall provide good torque transfer over a high temperature range at low thickness and weight of the housing.

[0007] The object of the invention is solved by a lamination sheet as disclosed in the opening paragraph, which additionally comprises a ring shaped second section made of aluminum and a ring shaped transition section between the first section and the second section, which starting at a border to the first section and ending at a border to the second section changes its characteristics from soft iron to aluminum.

[0008] Furthermore, the invention is solved by a lamination stack, which comprises a plurality of lamination sheets of the above kind being stacked over one another.

[0009] Further on, the invention is solved by an electric machine with a stator and a rotor being rotatably arranged in the stator, wherein the stator comprises a stator lamination stack of the above kind and / or wherein the rotor comprises a rotor lamination stack of the above kind.

[0010] In addition, the object of the invention is also solved by a vehicle driven by an electric machine of the above kind.

[0011] In one embodiment, the lamination sheet or parts thereof can be made by means of a metal printing process. In particular, the first section, the second section and the transition section each can be made by printing and sintering a base material. The first section can be made by printing and sintering a soft iron base material, the second section can be made by printing and sintering an aluminum base material, and the transition section can be made by printing and sintering i) a transition base material or ii) soft iron base material and the aluminum base material. In case i), the transition section is printed by use of a dedicated 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.

[0012] Accordingly, the object of the invention is also solved by a method of manufacturing a lamination sheet for a lamination stack of an electric machine, which comprises the steps: printing with a soft iron base material a ring shaped first section with recesses for accommodating a winding of the electric machine, printing with an aluminum base material a ring shaped second section and printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material a ring shaped transition section between the first section and the second section, wherein the transition section starting at a border to the first section and ending at a border to the second section changes its characteristics from soft iron to aluminum and heating and sintering the lamination sheet.

[0013] Here, heating and sintering the sections of the lamination sheet is done at once. That means, first, all sections are printed and then all sections are heated and sintered at once. 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 can be printed and then the second section can be printed.

[0014] In addition, the object of the invention is solved by a method of manufacturing a lamination sheet for a lamination stack of an electric machine, which comprises the steps: printing with a soft iron base material a ring shaped first section with recesses for accommodating a winding of the electric machine, heating and sintering the first section, printing with an aluminum base material a ring shaped second section, printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material a ring shaped transition section between the first section and the second section, wherein the transition section starting at a border to the first section and ending at a border to the second section changes its characteristics from soft iron to aluminum and heating and sintering the second section and the transition section. Here, heating and sintering the sections of the lamination sheet is done in two steps. That means, in a first step, the first section is printed and then heated and sintered, and in a second step, the second section and the transition section are printed and then heated and sintered. Accordingly, the first section is already solid when the second section and the transition section are printed.

[0015] Finally, the object of the invention can also be solved by a method of manufacturing a lamination stack for an electric machine, which comprises the steps: stacking a plurality of lamination sheets of the above kind or stacking a plurality of lamination sheets made by a method of the above kind and interconnecting the second sections of the plurality of lamination sheets by heating the same up to the melting point of aluminum at least locally.

[0016] The proposed measures generally allow a better connection between a lamination stack and a housing because of the smoother material changeover provided by the transition section. Accordingly, a connection between a lamination stack having the proposed lamination sheets and a housing provides good torque transfer over a high temperature range at low thickness and weight of the housing. Inter alia, also sound emanation from the electric machine can be reduced by the proposed measures. Concluding, the proposed measures provide better characteristics and better fitting behavior between the housing and lamination stack in general and in detail: a more stable connection between housing and lamination stack, an improved heat transfer from lamination stack to the housing, allows for higher tolerances of housing what reduces costs, allows higher torque transfer between housing and lamination.

[0017] In case that the second sections of the plurality of lamination sheets are interconnected by heating the same up to the melting point of aluminum at least locally, moreover, the stability of the lamination stack can be improved. In fact, the interconnected second sections form a kind of an integrated housing. On the one hand, this eases mounting the lamination stack into an external housing, on the other hand, a distinct (external) housing can be saved at all. In this case, an aluminum housing is formed by the lamination sheets themselves. In particular, the second sections of the plurality of lamination sheets can be interconnected by means of laser welding. The lamination stack generally a) can be embodied as a stator lamination stack, wherein the transition section is arranged radially outwards of the first section and wherein the second section is arranged radially outwards of the transition section in case of an internal rotor machine, or wherein the transition section is arranged radially inwards of the first section and wherein the second section arranged radially inwards of the transition section in case of an external rotor machine, or b) can be embodied as a rotor lamination stack, wherein the transition section is arranged radially inwards of the first section and wherein the second section is arranged radially inwards of the transition section in case of an internal rotor machine, or wherein the transition section is arranged radially outwards of the first section and wherein the second section is arranged radially outwards of the transition section in case of an external rotor machine.

[0018] Accordingly, the stator of the electric machine can comprise a stator lamination stack according to case a) and / or the rotor of the electric machine can comprise a rotor lamination stack according to case b).

[0019] It should be noted that although printing of the lamination sheet or parts thereof is advantageous, other production methods are possible as well. In particular, the first section can be cut out or punched out of a metal sheet and the second section and the transition section can be printed. This is similar to the aformentioned method, where the (printed) first section is already solid when the second section and the transition section are printed.

[0020] Further advantageous embodiments are disclosed in the claims and in the description as well as in the figures.

[0021] In general, the transition section can be made with a transition material, which in the transition section changes said characteristics continuously or in a stepped way. In particular, the change can be based on a variation of a mixture of the transition material, what provides the possibility of changing the material characteristics in the transition section continuously. For example, the mixture of the transition material can continuously be varied during a metal printing process. In another variant, a plurality of thinner rings can be made in the transition section, each having different material characteristics. In this way, a stepped change of the material characteristics in the transition section can be provided. For example, the mixture of the transition material can be varied during a metal printing process in a stepped way for this reason. It should also be noted that the plurality of thinner rings can flow into one another during heating and sintering thus smoothening the change of the material characteristics within the transition section.

[0022] In another embodiment, the first section and the second section both reach into the transition section, wherein said change of characteristics is based on a share of the first section and the second section on the transition section. For example, a pattern can be printed with the soft iron base material and the aluminum base material in the transition section, wherein the pattern on a macroscopic scale provides the changing characteristics in the transition section. The pattern can comprise circles, ovals, triangles, rectangles, trapezoids, and so on. Moreover, the pattern can flow into one another during heating and sintering to provide a pseudo continuous change of the material characteristics within the transition section.

[0023] Advantageously, the first section, the second section and / or the transition section can be printed by means of a screen printing method. In this way, the lamination sheets can be produced very fast. However, printing may also be done by a jet printer. In addition, both methods can be mixed. For example, the first section and the second section can be made by means of a metal screen printing process, whereas the transition section can be printed by means of a jet printing process. In this way, the characteristics in the transition section can be varied very precisely.

[0024] In another advantageous embodiment, heating and sintering the first section and the transition section is done by means of induction heating and heating and sintering the second section is done by means of heat transfer from the first section and the transition section to the second section. Here, the magnetic conduction of the soft iron is used to concentrate the heat to the first section and partly to the transition section so as to distinctively melt the soft iron particles in the first section and the transition section. In contrast, the aluminum of the second section is not actively heated but melt by heat transfer from the first section and the transition section to the second section. In this way, on the one hand, the soft iron with the comparably high melting point and, on the other hand, the aluminum with the comparably low melding point, can be sintered in a very good way and without overheating the aluminum and without underheating the soft iron.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] The invention now is described in more detail hereinafter with reference to particular embodiments, which the invention however is not limited to.

[0027] Fig. 1 shows a half sectional view of an exemplary electric machine;

[0028] Fig. 2 shows a front view of an exemplary stator lamination sheet;

[0029] Fig. 3 shows a detailed view of the stator lamination sheet of Fig. 2;

[0030] Fig. 4 shows an embodiment where the first section and the second section both reach into the transition section and

[0031] Fig. 5 shows a schematic view of an electric vehicle.

[0032] DETAILED DESCRIPTION

[0033] Generally, same parts or similar parts are denoted with the same / similar names and reference signs. The features disclosed in the description apply to parts with the same / similar names respectively reference signs. Indicating the orientation and relative position is related to the associated figure.

[0034] Fig. 1 shows a half sectional view of an electric machine 1 , which comprises a rotor shaft 2 and a rotor 3 mounted thereon, wherein the rotor shaft 2 is rotatably supported by (roller)bearings 4a, 4b around a rotor axis RA. Moreover, the electric machine 1 comprises a stator 5, a first bearing shield 6, a second bearing shield 7 and a stator housing 8, in which the stator 5 is arranged. In the first bearing shield 6, the first bearing 4a is arranged, and in the second bearing shield 7, the second bearing 4b is arranged. The first bearing shield 6, the second bearing shield 7 and the stator housing 8 together form a machine housing 9 or are at least parts thereof. The stator 5 comprises a stator lamination stack 10, which comprises a plurality of stator lamination sheets 1 1 stacked over one another along the stator axis or rotor axis RA respectively. Moreover, the stator 5 comprises stator windings 12 or stator magnets alternatively, which are arranged in the stator lamination stack 10. Similarly, the rotor 3 comprises a rotor lamination stack 13, which comprises a plurality of rotor lamination sheets 14 stacked over one another along the rotor axis RA. Moreover, the rotor 3 comprises rotor windings or rotor magnets arranged in the rotor lamination stack 13 (not shown).

[0035] Figs. 2 and 3 show an exemplary stator lamination sheet 11 a. Fig. 2 shows a front view and Fig. 3 shows a detailed view of the stator lamination sheet 1 1 a.

[0036] The stator lamination sheet 1 1 a comprises an inner edge B and an outer edge C and comprises a ring shaped first section 15a made of soft iron with recesses 16 for accommodating a stator winding 12. Further on, the stator lamination sheet 11 a comprises a ring shaped second section 17a made of aluminum and a ring shaped transition section 18a between the first section 15a and the second section 17a. The transition section 18a starting at a border D to the first section 15a and ending at a border E to the second section 17a changes its characteristics from soft iron to aluminum.

[0037] Generally, the first section 15a, the second section 17a and the transition section 18a each can be made by printing and sintering a base material. For example, the first section 15a can be made by printing and sintering a soft iron base material, the second section 17a can be made by printing and sintering an aluminum base material, and the transition section 18a can be made by printing and sintering i) a transition base material or ii) soft iron base material and the aluminum base material. In case i), the transition section 18a is printed by use of a dedicated transition base material, and in case ii), the transition section 18a is printed with a mixture of the soft iron base material and the aluminum base material.

[0038] For example, printing can be done by means of a screen printing method. In this way, the stator lamination sheets 1 1 , 1 1 a for a stator lamination stack 10 can be produced very fast. However, printing may also be done by a jet printer. In addition, both methods can be mixed. For example, the first section 15a and the second section 17a can be made by means of a metal screen printing process, whereas the transition section 18a can be printed by means of a jet printing process. In this way, the characteristics in the transition section 18a can be varied very precisely.

[0039] A method of manufacturing a lamination sheet 11 , 1 1 a can comprise the following steps: printing with a soft iron base material the ring shaped first section 15a with recesses 16 for accommodating the winding 12 of the electric machine 1 , printing with an aluminum base material the ring shaped second section 17a and printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material the ring shaped transition section 18a between the first section 15a and the second section 17a, wherein the transition section 18a starting at a border D to the first section 15a and ending at a border E to the second section 17a, 17b changes its characteristics from soft iron to aluminum and heating and sintering the lamination sheet 11 , 11 a.

[0040] Here, heating and sintering the sections 15a, 17a, 18a of the stator lamination sheet 11 , 1 1 a is done at once. That means, first, all sections 15a, 17a, 18a are printed and then all sections 15a, 17a, 18a are heated and sintered at once. 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.

[0041] An alternative method of manufacturing a lamination sheet 1 1 , 11 a can comprise the following steps: printing with a soft iron base material the ring shaped first section 15a with recesses 16 for accommodating the winding 12 of the electric machine 1 , heating and sintering the first section 15a, printing with an aluminum base material the ring shaped second section 17a, printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material the ring shaped transition section 18a between the first section 15a and the second section 17a, wherein the transition section 18a starting at a border D to the first section 15a and ending at a border E to the second section 17ab changes its characteristics from soft iron to aluminum and heating and sintering the second section 17a and the transition section 18a. Here, heating and sintering the sections 15a, 17a, 18a of the stator lamination sheet 11 , 11 a is done in two steps. That means, 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.

[0042] Generally, the transition section 18a can be made with a transition material, which in the transition section 18a changes said characteristics continuously or in a stepped way. In particular, the change can be based on a variation of a mixture of the transition material, i.e. based on a variation of soft iron particles and aluminum particles. For example, the mixture of the transition material can continuously be varied during the metal printing process. In another variant, a plurality of thinner rings can be made in the transition section 18a, each having different material characteristics. In this way, a stepped change of the material characteristics in the transition section 18a can be provided. For example, the mixture of the transition material can be varied during the metal printing process in a stepped way for this reason. It should also be noted that the plurality of thinner rings can flow into one another during heating and sintering and thus smoothening the change of the material characteristics within the transition section 18a.

[0043] In a preferred embodiment, heating and sintering the first section 15a and the transition section 18a can be done by means of induction heating, and heating and sintering the second section 17a can be done by means of heat transfer from the first section 15a and the transition section 18a to the second section 17a. In this way, the magnetic conduction of the soft iron particles is used to concentrate the heat to the first section 15a and the transition section 18a so as to distinctively melt the soft iron particles in the first section 15a and the transition section 18a. In contrast, the aluminum of the second section 17a is not actively heated but melt by heat transfer from the first section 15a and the transition section 18a to the second section 17a. In this way, on the one hand, the soft iron with the comparably high melting point and, on the other hand, the aluminum with the comparably low melding point, can be sintered in a very good way and without overheating the aluminum and without underheating the soft iron. It should be noted that although printing of the lamination sheet 11 , 1 1 a or parts thereof is advantageous, other production methods are possible as well. In particular, the first section 15a can be cut out or punched out of a metal sheet and the second section 17a and the transition section 18a can be printed.

[0044] In yet another advantageous embodiment, a method of manufacturing a stator lamination stack 10 can comprise the following steps: stacking a plurality of stator lamination sheets 11 , 1 1 a and interconnecting the second sections 17a of the plurality of lamination sheets 11 , 11 a by heating the same up to the melting point of aluminum at least locally. In this way, the stability of the stator lamination stack 10 can be improved. In fact, the interconnected second sections 17a form a kind of an integrated housing. On the one hand, this eases mounting the stator lamination stack 10 into the stator housing 8, on the other hand, a distinct stator housing 8 can be saved at all. In this case, an aluminum housing is formed by the stator lamination sheets 11 , 1 1 a themselves. In particular, the second sections 17a of the plurality of stator lamination sheets 11 , 1 1 a can be interconnected by means of laser welding.

[0045] In a case a), the lamination stack 11 , 1 1 a can embodied as a stator lamination stack 1 1 , 11 a as is depicted in Fig. 1 . The transition section 18a can be arranged radially outwards of the first section 15a, and the second section 17a can be arranged radially outwards of the transition section 18a in case of an internal rotor machine like this is the case in Figs. 2 and 3. In this case, the recesses 16 open to the inner edge B of the stator lamination sheet 1 1 a and the second section 17a is arranged at the outer edge C of the stator lamination sheet 1 1 a. However, the transition section 18a can also be arranged radially inwards of the first section 15a, and the second section 17a can be arranged radially inwards of the transition section 18a in case of an external rotor machine. In this case, the recesses 16 open to the outer edge C of the stator lamination sheet 11 a and the second section 17a is arranged at the inner edge B of the stator lamination sheet 1 1 a.

[0046] In a case b), the lamination stack 11 , 1 1 a can be embodied as a rotor lamination stack 13. The transition section 18a can be arranged radially inwards of the first section 15a, and the second section is 17a can be arranged radially inwards of the transition section 18a in case of an internal rotor machine. In this case, the recesses 16 open to the outer edge C of the rotor lamination sheet 14 and the second section 17a is arranged at the inner edge B of the rotor lamination sheet 14. In case of an external rotor machine, the transition section 18a can be arranged radially outwards of the first section 15a and the second section 17a can be arranged radially outwards of the transition section 18a. In this case, the recesses 16 open to the inner edge B of the rotor lamination sheet 14 and the second section 17a is arranged at the outer edge C of the rotor lamination sheet 14.

[0047] So, the stator 5 of the electric machine 1 can comprise a stator lamination stack 10 according to case a) and / or the rotor 3 of the electric machine 1 can comprise a rotor lamination stack 13 according to case b).

[0048] In the examples presented hereinbefore, the transition section 18a was made with a (distinct) transition material. However, the transition section 18b may also be formed by the first section 15b and the second section 17b like this is depicted in Fig. 4. Here, the first section 15b and the second section 17b both reach into the transition section 18b, wherein said change of characteristics is based on a share of the first section 15b and the second section 17b on the transition section 18b. For example, a pattern can be printed with the soft iron base material and the aluminum base material in the transition section 18b, wherein the pattern on a macroscopic scale provides the changing characteristics in the transition section 18b. Moreover, the pattern can flow into one another during heating and sintering to provide a pseudo continuous change of the material characteristics within the transition section 18b. In the example of Fig. 4, teeth of the first section 15b and the second section 17b reach into the transition section 18b and form the same. However, other shapes are possible as well. 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 the density of said holes, the characteristics of transition section 18b can be defined.

[0049] The proposed measures generally allow a better connection between a lamination stack 10, 13 and a housing 9 because of the smoother material changeover provided by the transition section 18a, 18b. Accordingly, a connection between a lamination stack 10, 13 having the proposed lamination sheets 11 , 11 a, 11 b, 14 and a housing 9 provides: a stable connection between the lamination stack 10, 13 and the housing 9 and thus good torque transfer over a high temperature range, low thickness and weight of the housing 9, comparably large tolerances for the lamination stack 10, 13 and the housing 9, improved heat transfer from the lamination stack 10, 13 to the housing 9 and reduced sound emanation from the electric machine 1 .

[0050] Fig. 5 finally shows an electric vehicle 19 with an electric machine 1 as defined hereinbefore, which is provided to propel the electric vehicle 19. In detail, the electric machine 1 is coupled to a gearbox 20, side shafts 21 and finally to the wheels 22. The electric machine 1 may be provided for powering the electric vehicle 19 permanently in a pure electric car or intermittently, e.g. in combination with a combustion engine in a hybrid car.

[0051] It is noted that the invention is not limited to the embodiments disclosed hereinbefore, but combinations of the different variants are possible. In reality, the electric machine 1 and the electric vehicle 19 may have more or less 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 Figs. Moreover, the description may comprise subject matter of further independent inventions. It should also be noted that the use of a gearbox 20 is not mandatory, and the electric vehicle 19 may be propelled by the electric machine 1 solely.

[0052] It should also be noted that the term "comprising" does not exclude other elements and the use of articles "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

[0053] List of References

[0054] 1 electric machine

[0055] 2 rotor shaft

[0056] 3 rotor

[0057] 4a, 4b bearing

[0058] 5 stator

[0059] 6 first bearing shield

[0060] 7 second bearing shield

[0061] 8 stator housing

[0062] 9 machine housing

[0063] 10 lamination stack (stator lamination stack)

[0064] 11 , 11a, 11b lamination sheet (stator lamination sheet)

[0065] 12 stator winding

[0066] 13 lamination stack (rotor lamination stack)

[0067] 14 lamination sheet (rotor lamination sheet)

[0068] 15a, 15b first section

[0069] 16 recess

[0070] 17a, 17b second section

[0071] 18a, 18b transition section

[0072] 19 vehicle

[0073] 20 gearbox

[0074] 21 side shaft

[0075] 22 wheel

[0076] RA axis (rotor axis / stator axis)

[0077] B inner edge of ring structure

[0078] C outer edge of ring structure

[0079] D border first section / transition section

[0080] E border second section / transition section

Claims

Claims1. Lamination sheet (1 1 , 11 a, 11 b, 14) for a lamination stack (10, 13) of an electric machine (1 ), comprising a ring shaped first section (15a, 15b) made of soft iron with recesses (16) for accommodating a winding (12) of the electric machine (1 ), characterized in a ring shaped second section (17a, 17b) made of aluminum and a ring shaped transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b), which starting at a border (D) to the first section (15a, 15b) and ending at a border (E) to the second section (17a, 17b) changes its characteristics from soft iron to aluminum.

2. Lamination sheet (1 1 , 11 a, 11 b, 14) according to claim 1 , characterized in that the first section (15a, 15b), the second section (17a, 17b) and the transition section (18a, 18b) each are made by printing and sintering a base material.

3. Lamination sheet (1 1 , 11 a, 11 b, 14) according to claim 1 or 2, characterized in that the transition section (18a, 18b) is made with a transition material, which in the transition section (18a, 18b) changes said characteristics continuously or in a stepped way.

4. Lamination sheet (1 1 , 11 a, 11 b, 14) according to any one of claims 1 to 3, characterized in that the change is based on a variation of a mixture of the transition material.

5. Lamination sheet (1 1 , 11 a, 11 b, 14) according to any one of claims 1 to 3, characterized in that the first section (15a, 15b) and the second section (17a, 17b) both reach into the transition section (18a, 18b), wherein said change of characteristics is based on a share of the first section (15a, 15b) and the second section (17a, 17b) on the transition section (18a, 18b).

6. Lamination stack (10, 13), comprising a plurality of lamination sheets (11 , 1 1 a, 1 1 b, 14) according to any one of the claims 1 to 5 being stacked over one another.

7. Lamination stack (1 1 , 11 a, 11 b, 14) according to claim 6, characterized in that the lamination stack (1 1 , 11 a, 11 b, 14)a) is embodied as a stator lamination stack (10), wherein the transition section (18a, 18b) is arranged radially outwards of the first section (15a, 15b) and wherein the second section (17a, 17b) is arranged radially outwards of the transition section (18a, 18b) in case of an internal rotor machine, or wherein the transition section (18a, 18b) is arranged radially inwards of the first section (15a, 15b) and wherein the second section (17a, 17b) arranged radially inwards of the transition section (18a, 18b) in case of an external rotor machine, or b) is embodied as a rotor lamination stack (13), wherein the transition section (18a, 18b) is arranged radially inwards of the first section (15a, 15b) and wherein the second section is (17a, 17b) arranged radially inwards of the transition section (18a, 18b) in case of an internal rotor machine, or wherein the transition section (18a, 18b) is arranged radially outwards of the first section (15a, 15b) and wherein the second section is (17a, 17b) arranged radially outwards of the transition section (18a, 18b) in case of an external rotor machine.

8. Electric 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 lamination stack (10) according to case a) of claim 7 and / or the rotor (3) comprises a rotor lamination stack (13) according to case b) of claim 7.

9. Vehicle (19), driven by an electric machine (1) as claimed in claim 1.

10. Method of manufacturing a lamination sheet (11 , 11 a, 11b, 14) for a lamination stack (10, 13) of an electric machine (1), comprising the steps printing with a soft iron base material a ring shaped first section (15a, 15b) with recesses (16) for accommodating a winding (12) of the electric machine (1), printing with an aluminum base material a ring shaped second section (17a, 17b) and printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material a ring shaped transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b), wherein the transition sec-tion (18a, 18b) starting at a border (D) to the first section (15a, 15b) and ending at a border (E) to the second section (17a, 17b) changes its characteristics from soft iron to aluminum and heating and sintering the lamination sheet (11 , 1 1 a, 1 1 b, 14).11 . Method of manufacturing a lamination sheet (11 , 11 a, 1 1 b, 14) for a lamination stack (10, 13) of an electric machine (1 ), comprising the steps printing with a soft iron base material a ring shaped first section (15a, 15b) with recesses (16) for accommodating a winding (12) of the electric machine (1 ), heating and sintering the first section (15a, 15b), printing with an aluminum base material a ring shaped second section (17a, 17b), printing i) with a transition base material or ii) with the soft iron base material and the aluminum base material a ring shaped transition section (18a, 18b) between the first section (15a, 15b) and the second section (17a, 17b), wherein the transition section (18a, 18b) starting at a border (D) to the first section (15a, 15b) and ending at a border (E) to the second section (17a, 17b) changes its characteristics from soft iron to aluminum and heating and sintering the second section (17a, 17b) and the transition section (18a, 18b).

12. Method as claimed in claim 10 or 1 1 , 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 method.

13. Method as claimed in any one of claims 10 to 12, characterized in that heating and sintering the first section (15a, 15b) and the transition section (18a, 18b) is done by means of induction heating and heating and sintering the second section (17a, 17b) is done by means of heat transfer from the first section (15a, 15b) and the transition section (18a, 18b) to the second section (17a, 17b).

14. Method of manufacturing a lamination stack (10, 13) for an electric machine (1 ), comprising the steps stacking a plurality of lamination sheets (11 , 1 1 a, 1 1 b, 14) according to any one of claims 1 to 5 or stacking a plurality of lamination sheets (11 , 1 1 a, 1 1 b, 14) made by a method according to any one of claims 10 to 13 andinterconnecting the second sections (17a, 17b) of the plurality of lamination sheets (11 , 1 1 a, 1 1 b, 14) by heating the same up to the melting point of aluminum at least locally.

15. Method according to claim 14, characterized in that the second sections (17a, 17b) of the plurality of lamination sheets (11 , 11 a, 11 b, 14) are interconnected by means of laser welding.

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