Lamination stack for an electric machine with improved cooling and method of making such a lamination stack

Abstract

A lamination stack (10, 13) for an electric machine (1) is disclosed, wherein the lamina- tions (11, 14) each have a ring shaped base structure (20) with recesses (21), which open to an inner edge (D) or outer edge (E) of the base structure (20). The recesses (21) have inner lamination regions (G) and lamination edge regions (H) arranged adjacent to the inner lamination regions (G) where the recesses (21) open. Inner stack regions (B) of the lamina- tion stack (10, 13) for windings (12, 15) or magnets are formed by interconnected inner lam- ination regions (G). In addition, stack edge regions (C) of the lamination stack (10, 13) are formed by interconnected lamination edge regions (H), wherein stack pipes (16) run in said stack edge regions (C). Further on, a stator (2), a rotor (3) and an electric machine (1) with such a lamination stack (10, 13) are disclosed. Finally, a vehicle (23) with such an electric machine (1) and methods of making such a lamination stack (10, 13) are disclosed.

Description

[0001] Lamination stack for an electric machine with improved cooling and method of making such a lamination stack

[0002] TECHNICAL FIELD

[0003] The invention relates to a lamination stack for an electric machine, wherein the lamination stack comprises a plurality of laminations stacked over one another. The laminations each have a ring shaped base structure with recesses, wherein the recesses open to an inner edge or outer edge of the base structure. Moreover, the recesses have inner lamination regions and lamination edge regions, each of which is arranged adjacent to one of the inner lamination regions where the recesses open. The lamination stack comprises a plurality of inner stack regions, which are formed by interconnected ones of the inner lamination regions and which are provided for accommodating windings or magnets. Moreover, the invention relates to a stator for an electric machine, which comprises a lamination stack of the above kind with stator windings or stator magnets arranged in the inner stack regions. Further on, the invention relates to a rotor for an electric machine, which comprises a lamination stack of the above kind with rotor windings or rotor magnets arranged in the inner stack regions. In addition, the invention relates to an electric machine, which comprises a stator of the above kind and / or a rotor of the above kind and to a vehicle with an electric machine of said kind, which is provided for propelling the vehicle. Finally, the invention relates to methods of manufacturing a lamination stack for an electric machine.

[0004] BACKGROUND ART

[0005] A lamination stack, a stator, a rotor, an electric machine, a vehicle and a method of the above kinds are generally known. Generally, pin-like protrusions are formed in the laminations by neighboring recesses, which protrusions tend to vibrate or wobble during operation of the electric machine. This is particularly true if the laminations of the lamination stack are not sufficiently pressed or cannot sufficiently be pressed onto each other in this region, for example because of technical limitations and limited space for connecting elements. In any case, the recesses reduce the mechanical stability of the lamination stack compared a body without such recesses. Moreover, the magnetic flux, strictly speaking the magnetic losses, produce heat within the base structure what particularly heats up the ends of said pin-like protrusions and what can lead to problems during operation of the electric machine. DISCLOSURE OF INVENTION

[0006] Accordingly, an object of the invention is to provide an improved lamination stack, an improved stator, an improved rotor, an improved electric machine, an improved vehicle and an improved method of making a lamination stack. In particular, a solution shall be proposed, which avoids unwanted vibration of the pin-like protrusions, which increases the mechanical stability of the lamination stack as a whole and which avoids excessive temperatures at the ends of said pin-like protrusions.

[0007] The object of the invention is solved by a lamination stack as disclosed in the opening paragraph, wherein the lamination stack comprises a plurality of stack edge regions, which are formed by interconnected ones of the lamination edge regions, and a plurality of stack pipes, each of which runs in one of the stack edge regions.

[0008] Moreover, the invention is solved by a stator for an electric machine, which comprises a lamination stack of the above kind with stator windings or stator magnets arranged in the inner stack regions.

[0009] Further on, the invention is solved by a rotor for an electric machine, which comprises a lamination stack of the above kind with rotor windings or rotor magnets arranged in the inner stack regions.

[0010] In addition, the invention is solved by an electric machine, which comprises a stator of the above kind and / or a rotor of the above kind.

[0011] Additionally, the object of the invention is also solved by a vehicle with an electric machine of said kind, which is provided for propelling the vehicle.

[0012] The object of the invention is also solved by a method of manufacturing a lamination stack for an electric machine, which comprises the steps of: stacking a plurality of laminations over one another, wherein the laminations each have a ring shaped base structure with recesses, wherein the recesses open to an inner edge or outer edge of the base structure and have inner lamination regions and lamination edge regions, each of which is arranged adjacent to one of the inner lamination regions where the recesses open, thereby forming

[0013] - a plurality of inner stack regions, which are formed by interconnected ones of the inner lamination regions and which are provided for accommodating windings or magnets, and

[0014] - a plurality of stack edge regions, which are formed by interconnected ones of the lamination edge regions, and arranging a plurality of stack pipes in the lamination stack, each of which runs in one of the stack edge regions.

[0015] In this embodiment, dedicated stack pipes are arranged in the stack edge regions. For example, the stack pipes may be glued to the ring shaped base structure. If the stack pipes are made of metal, the can also be welded or soldered to the ring shaped base structure.

[0016] The object of the invention can also be solved by an alternative method of manufacturing a lamination stack for an electric machine, which comprises the steps of: forming a plurality of laminations, each having a ring shaped base structure with recesses, wherein the recesses open to an inner edge or outer edge of the base structure and have inner lamination regions and lamination edge regions, each of which is arranged adjacent to one of the inner lamination regions where the recesses open, forming annular structures, each in one of the lamination edge regions, stacking a plurality of laminations over one another, thereby forming

[0017] - a plurality of inner stack regions, which are formed by interconnected ones of the inner lamination regions and which are provided for accommodating windings or magnets,

[0018] - a plurality of stack edge regions, which are formed by interconnected ones of the lamination edge regions, and

[0019] - a plurality of stack pipes, which are formed by interconnected ones of the annular structures in the stack edge regions.

[0020] In this embodiment, there are no dedicated stack pipes but the stack pipes are formed by stacking the laminations. In more detail, each of the laminations comprises annular structures in the lamination edge regions which together form the plurality of stack pipes. In particular, there is one annular structure per lamination edge region. The laminations can be glued together, at least in the lamination edge regions so that the stack pipes, which are formed by interconnected ones of the annular structures, are liquid tight or airtight. In one embodiment, in a case a), in a first step, the laminations each are coated with a first component of a two component glue after the annular structures have been formed but before stacking the laminations over one another, in a second step, a second component of the two component glue is applied to the first component, and in a third step, the laminations are stacked over one another before the two component glue hardens.

[0021] In an alternative process, in a case b), in a first step, the laminations each are coated with a thermoplastic material after the annular structures have been formed but before stacking the laminations over one another, in a second step, the laminations are stacked over one another, and in a third step, the lamination stack is heated above a melting temperature of the thermoplastic material. In particular, the thermoplastic material may be a thermosetting varnish, which is dried before stacking the laminations over one another. The thermosetting varnish may also be applied to a sheet material for the laminations and dried even before the ring shaped base structure is formed.

[0022] The proposed measures provide improved mechanical stability of a lamination stack and improved cooling in a synergetic way. In detail, on the one hand, the pin-like protrusions of the base structure are interconnected in the region where the recesses of the base structure open. Accordingly, a tendency of the pin-like protrusions to vibrate or wobble is suppressed and the mechanical stability of the lamination stack is improved as a whole. On the other hand, the proposed measures allow to cool a lamination stack in a temperature critical region, i.e. where the recesses of the base structure open. Both functions are provided by the plurality of stack pipes.

[0023] Generally, if the recesses of a stator lamination stack open to an inner edge of the base structure, a stator for an internal rotor machine is formed. If the recesses open to an outer edge of the base structure, a stator for an external rotor machine is formed. If the recesses of a rotor lamination stack open to an outer edge of the base structure, a rotor for an internal rotor machine is formed. If the recesses open to an inner edge of the base structure, a rotor for an external rotor machine is formed.

[0024] Further advantageous embodiments are disclosed in the claims and in the description as well as in the figures. Preferably, the stack pipes or the annular structures respectively can be made of a material having a magnetic conductivity of p.R < 10. In this way, the stack pipes or the annular structures do not influence the magnetic flux within the base structure much. In contrast, the base structures of the stator laminations are for guiding the magnetic flux and preferably have a magnetic conductivity of gR > 20. In particular, the stack pipes or the annular structures respectively can be made of aluminum, stainless steel or plastic. If the annular structures are printed, accordingly, a base material can be aluminum, stainless steel or plastic. In contrast, the base structure preferably is made of soft iron.

[0025] Advantageously, the annular structures can be made by use of a metal printing process. In particular, a metal screen printing process and / or a metal jet printing process can be used for this reason.

[0026] Generally, the ring shaped base structure may be punched or cut out of a metal sheet. Cutting, for example can be done by means of a laser. However the ring shaped base structure can be formed by use of a metal printing process, too. In this case, the annular structures can be printed before the ring shaped base structure is printed or after the ring shaped base structure has been printed.

[0027] In an advantageous embodiment, the lamination stack can comprise pipe extensions, each of which is hydraulically connected to one of the stack pipes and runs out of the lamination stack, wherein spray nozzles or bores are arranged in the pipe extensions. In case of a rotor, the stack pipes or pipe extensions can hydraulically be connected to a central shaft bore, through which a coolant or lubricant is pumped. The stack pipes of the electric machine can hydraulically be connected to a cooling circuit of the vehicle, and the spray nozzles or bores can be directed to the stator windings or the rotor windings. By the proposed measures, the stator windings and / or the rotor windings can be cooled.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] The invention now is described in more detail hereinafter with reference to particular embodiments, which the invention however is not limited to.

[0030] Fig. 1 shows a half sectional view of an exemplary electric machine; Fig. 2 shows a front view of an exemplary lamination;

[0031] Fig. 3 shows a detailed view of the lamination of Fig. 1 ;

[0032] Fig. 4 like Fig. 3 but with windings and annular sections in the recesses of the lamination and

[0033] Fig. 5 shows a schematic view of an electric vehicle.

[0034] DETAILED DESCRIPTION

[0035] 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.

[0036] Fig. 1 shows a schematic cross sectional view of an exemplary electric machine 1. The electric machine 1 comprises a stator 2 and a rotor 3 mounted on a rotor shaft 4, which is rotatably supported in (roller)bearings 5a, 5b around a rotor axis A. Moreover, the electric machine 1 comprises a first bearing shield 6, in which the first bearing 5a is arranged, a second bearing shield 7, in which the second bearing 5b is arranged, and a stator housing 8, in which the stator 2 is mounted. The bearing shields 6, 7 and the stator housing 8 together form the machine housing 9 of the electric machine 1 or are at least parts of the same.

[0037] The stator 2 comprises a stator lamination stack 10 with a plurality of stator laminations 11 stacked over one another along the stator axis or the rotor axis A respectively. Further on, the stator 2 comprises stator windings 12 arranged in the stator lamination stack 10 in inner stack regions B of the stator lamination stack 10. Alternatively, stator magnets (not shown) may be arranged in inner stack regions B of the stator lamination stack 10.

[0038] The rotor 3 comprises a rotor lamination stack 13 with a plurality of rotor laminations 14 stacked over one another along the rotor axis A. In addition, the rotor 3 comprises rotor windings 15 arranged in the rotor lamination stack 13. Alternatively, rotor magnets (not shown) may be arranged in the rotor lamination stack 13. Further on, the stator lamination stack 10 comprises stack pipes 16 in the stack edge regions C of the stator lamination stack 10 and pipe extensions 17a, 17b on both sides of the stack pipes 16. The pipe extensions 17a, 17b are hydraulically connected to the stack pipes 16 and run out of the lamination stack 10. Moreover, the pipe extensions 17a, 17b comprise optional spray nozzles or bores 18, which are directed to the stator windings 12 and to the rotor windings 15 in this example. Finally, the pipe extensions 17a, 17b lead out of the machine housing 9 of the electric machine 1 , where the pipe extensions 17a, 17b and thus the stack pipes 16 can hydraulically be connected to an external cooling circuit.

[0039] The stator laminations 11 are interconnected by means of glue layers 18 in this embodiment. However, other connection methods are possible as well. For example, the stator laminations 1 1 can be held together by screws.

[0040] Fig. 2 now shows a front view of one of the stator laminations 1 1 . The stator laminations 1 1 each have a ring shaped base structure 20 with recesses 21 , wherein the recesses 21 open to an inner edge D or outer edge E of the base structure 20 where they form recess openings F.

[0041] Figs. 3 shows a detailed view of the stator lamination 11 of Fig. 2. As can be seen, the recesses 21 comprise inner lamination regions G and lamination edge regions H, each of which is arranged adjacent to one of the inner lamination regions G where the recesses 21 open (i.e. in the region of the recess opening F).

[0042] The inner stack regions B, which are provided for accommodating the stator windings 12 or the stator magnets and which are depicted in Fig. 1 , are formed by interconnected ones of the inner lamination regions G. The stack edge regions C, in which the stack pipes 16 run and which are depicted in Fig. 1 , too, are formed by interconnected ones of the lamination edge regions H.

[0043] A method of manufacturing a stator lamination stack 10 can comprise the following steps: stacking a plurality of stator laminations 11 over one another, wherein the stator laminations 1 1 each have a ring shaped base structure 20 with recesses 21 , wherein the recesses 21 open to an inner edge D or outer edge E of the base structure 20 and have inner lamination regions G and lamination edge regions H, each of which is arranged adjacent to one of the inner lamination regions G where the recesses 21 open, thereby forming a plurality of inner stack regions B, which are formed by interconnected ones of the inner lamination regions G and which are provided for accommodating stator windings 12 or stator magnets, and a plurality of stack edge regions C, which are formed by interconnected ones of the lamination edge regions H, and arranging a plurality of stack pipes 16 in the stator lamination stack 10, each of which runs in one of the stack edge regions C.

[0044] In this embodiment, dedicated continuous stack pipes 16 are arranged in the stack edge regions C. For example, the stack pipes 16 may be glued to the ring shaped base structure 20. If the stack pipes 16 are made of metal, they can also be welded or soldered to the ring shaped base structure 20.

[0045] An alternative method of manufacturing a stator lamination stack 10 can comprise the following steps: forming a plurality of stator laminations 1 1 , each having a ring shaped base structure 20 with recesses 21 , wherein the recesses 21 open to an inner edge D or outer edge E of the base structure 20 and have inner lamination regions G and lamination edge regions H, each of which is arranged adjacent to one of the inner lamination regions G where the recesses 21 open, forming annular structures 22, each in one of the lamination edge regions H, stacking a plurality of stator laminations 1 1 over one another, thereby forming

[0046] - a plurality of inner stack regions B, which are formed by interconnected ones of the inner lamination regions G and which are provided for accommodating stator windings 12 or stator magnets,

[0047] - a plurality of stack edge regions C, which are formed by interconnected ones of the lamination edge regions H, and

[0048] - a plurality of stack pipes 16, which are formed by interconnected ones of the annular structures 22 in the stack edge regions C.

[0049] In this case, there are no dedicated stack pipes 16 but the stack pipes 16 are formed by stacking the stator laminations 11. In this context, Fig. 4 shows the stator lamination of Fig. 3 with the stator windings 12 arranged in the inner stack regions B or in the inner lamination regions G respectively as well as with the annular structures 22 in the stack edge regions C or in the lamination edge regions H respectively. For example, the annular structures 22 can be made by use of a metal printing process. In particular, a metal screen printing process and / or a metal jet printing process can be used for this reason. In particular there is one annular structure 22 per lamination edge region H.

[0050] Generally, the ring shaped base structure 20 may be punched or cut out of a metal sheet. Cutting, for example can be done by means of a laser. However the ring shaped base structure 20 can be formed by use of a metal printing process, too. In this case, the annular structures 22 can be printed before the ring shaped base structure 20 is printed or after the ring shaped base structure 20 has been printed.

[0051] After the printed metal has been heated and sintered (and thus is solid then), the stator laminations 1 1 can be glued together for example by the glue layers 18. Gluing preferably at least is done in the lamination edge regions H so that the stack pipes 16, which are formed by interconnected ones of the annular structures 22, are liquid tight or airtight.

[0052] For example, in a case a), in a first step, the stator laminations 1 1 each are coated with a first component of a two component glue after the annular structures 22 have been formed but before stacking the stator laminations 11 over one another, in a second step, a second component of the two component glue is applied to the first component, and in a third step, the stator laminations 11 are stacked over one another before the two component glue hardens.

[0053] In an alternative process, in a case b), in a first step, the stator laminations 11 each are coated with a thermoplastic material after the annular structures 22 have been formed but before stacking the stator laminations 11 over one another, in a second step, the stator laminations 1 1 are stacked over one another, and in a third step, the stator lamination stack 10 is heated above a melting temperature of the thermoplastic material. In particular, the thermoplastic material may be a thermosetting varnish, which is dried before stacking the stator laminations 11 over one another. The thermosetting varnish may also be applied to a sheet material for the stator laminations 1 1 and dried even before the ring shaped base structure 20 is formed.

[0054] Generally, the stack pipes 16 or the annular structures 22 respectively can be made of a material having a magnetic conductivity of gR < 10. In this way, the stack pipes 16 or the annular structures 22 do not influence the magnetic flux within the base structure 20 much. In contrast, the base structures 20 of the stator laminations 10 for guiding the magnetic flux preferably have a magnetic conductivity of gR > 20. In particular, the stack pipes 16 or the annular structures 22 respectively can be made of aluminum, stainless steel or plastic. If the annular structures 22 are printed, accordingly, a base material can be aluminum, stainless steel or plastic. In contrast, the base structure 20 preferably is made of soft iron.

[0055] As already said, the stator 2 comprises a stator lamination stack 10 of the disclosed kind with stator windings 12 or stator magnets arranged in the inner stack regions B. If the recesses 21 open to an inner edge D of the base structure 20, a stator 2 for an internal rotor machine is formed (like this is the case in Fig. 1 ). If the recesses 21 open to an outer edge E of the base structure 20, a stator 2 for an external rotor machine is formed.

[0056] The examples presented so far relate to a stator lamination 11 and a stator lamination stack 10. However, the presented measures equally apply to a rotor lamination 14 and a rotor lamination stack 13. Hence, in the above disclosure, a rotor lamination 14 can replace a stator lamination 11 , and a rotor lamination stack 13 can replace the stator lamination stack 10. In a more general language, the term “stator lamination” may be replaced by “lamination”, and the term “stator lamination stack” may be replaced by “lamination stack”.

[0057] Hence, a rotor 3 for an electric machine 1 can comprise a (rotor) lamination stack 13 with rotor windings 15 or rotor magnets arranged in the inner stack regions B. If the recesses 21 open to an outer edge E of the base structure 20, a rotor 3 for an internal rotor machine is formed (like this is the case in Fig. 1 ). If the recesses 21 open to an inner edge D of the base structure 20, a rotor 3 for an external rotor machine is formed. The stack pipes 16 or pipe extensions 17a, 17b can hydraulically be connected to a central shaft bore in the rotor shaft 4, through which a coolant or lubricant is pumped to the stack pipes 16 or pipe extensions 17a, 17b.

[0058] Concluding, an electric machine 1 can comprise a stator 2 of the disclosed kind and / or a rotor 3 of the disclosed kind. It should also be note that spray nozzles or bores 18 of the rotor lamination stack 13 can be directed to the stator windings 12 and / or the rotor windings 15. Fig. 5 finally shows an electric vehicle 23 with an electric machine 1 as defined hereinbefore, which is provided to propel the electric vehicle 23. In detail, the electric machine 1 is coupled to an optional gearbox 24, side shafts 25 and finally to the wheels 26. The electric machine 1 may be provided for powering the electric vehicle 23 permanently in a pure electric car or intermittently, e.g. in combination with a combustion engine in a hybrid car. The stack pipes 16 of the electric machine 1 can hydraulically be connected to a cooling circuit of the vehicle 23, in particular via the pipe extensions 17a, 17b.

[0059] 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 23 may have more or less parts than shown in the figures. It is also noted that the electric machine 1 and the electric vehicle 23 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 24 is not mandatory, and the electric vehicle 23 may be propelled by the electric machine 1 solely.

[0060] 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.

[0061] List of References

[0062] 1 electric machine

[0063] 2 stator

[0064] 3 rotor

[0065] 4 rotor shaft

[0066] 5a, 5b bearing

[0067] 6 first bearing shield

[0068] 7 second bearing shield

[0069] 8 stator housing

[0070] 9 machine housing

[0071] 10 lamination stack (stator lamination stack)

[0072] 11 lamination (stator lamination)

[0073] 12 winding (stator winding)

[0074] 13 lamination stack (rotor lamination stack)

[0075] 14 lamination (rotor lamination)

[0076] 15 winding (rotor winding)

[0077] 16 stack pipe

[0078] 17a, 17b pipe extension

[0079] 18 spray nozzle or bore

[0080] 19 glue layer

[0081] 20 base structure

[0082] 21 recess

[0083] 22 annular structure

[0084] 23 vehicle

[0085] 24 gearbox

[0086] 25 side shaft

[0087] 26 wheel A axis (rotor axis / stator axis)

[0088] B inner stack region

[0089] C stack edge region

[0090] D (inner) edge of base structure E (outer) edge of base structure

[0091] F recess opening

[0092] G inner lamination region

[0093] H lamination edge region

Claims

Claims1. Lamination stack (10, 13) for an electric machine (1 ), wherein the lamination stack (10, 13) comprises a plurality of laminations (11 , 14) stacked over one another, wherein the laminations (1 1 , 14) each have a ring shaped base structure (20) with recesses (21 ), wherein the recesses (21 ) open to an inner edge (D) or outer edge (E) of the base structure (20) and have inner lamination regions (G) and lamination edge regions (H), each of which is arranged adjacent to one of the inner lamination regions (G) where the recesses (21 ) open, wherein the lamination stack (10, 13) comprises a plurality of inner stack regions (B), which are formed by interconnected ones of the inner lamination regions (G) and which are provided for accommodating windings (12, 15) or magnets characterized in that the lamination stack (10, 13) comprises a plurality of stack edge regions (C), which are formed by interconnected ones of the lamination edge regions (H), and a plurality of stack pipes (16), each of which runs in one of the stack edge regions (C).

2. Lamination stack (10, 13) according to claim 1 , characterized in that the stack pipes (16) are made of a material having a magnetic conductivity of p.R < 10.

3. Lamination stack (10, 13) according to claim 1 or 2, characterized in that the stack pipes (16) are made of aluminum, stainless steel or plastic.

4. Lamination stack (10, 13) according to any one of claims 1 to 3, characterized in that each of the laminations (1 1 , 14) comprises annular structures (22) in the lamination edge regions (H) which together form the plurality of stack pipes (16).

5. Lamination stack (10, 13) according to claim 4, characterized in that the annular structures (22) are made by use of a metal printing process.

6. Lamination stack (10, 13) according to any one of claims 1 to 5, characterized in that it comprises pipe extensions (17a, 17b), each of which is hydraulically connected to one of the stack pipes (16) and runs out of the lamination stack (10, 13), wherein spray nozzles or bores (18) are arranged in the pipe extensions (17a, 17b).

7. Stator (2) for an electric machine (1 ), comprising a lamination stack (10) according to any one of the claims 1 to 6 with stator windings (12) or stator magnets arranged in the inner stack regions (B).

8. Rotor (3) for an electric machine (1 ), comprising a lamination stack (13) according to any one of the claims 1 to 6 with rotor windings (15) or rotor magnets arranged in the inner stack regions (B).

9. Electric machine (1 ), comprising a stator (2) and a rotor (3), characterized in that the stator (2) is embodied according to claim 7 and / or the rotor (3) is embodied according to claim 8.

10. Electric machine (1 ) according to claim 9, characterized in that the spray nozzles or bores (18) of the lamination stack (10, 13) according to claim 6 are directed to the stator windings (12) or the rotor windings (15).11 . Vehicle (23), comprising an electric machine (1 ) according to claim 9 or 10 which is provided for propelling the vehicle (23).

12. Vehicle (23) according to claim 11 , characterized in that the stack pipes (16) of the electric machine (1 ) are hydraulically connected to a cooling circuit of the vehicle (23).

13. Method of manufacturing a lamination stack (10, 13) for an electric machine (1 ), comprising the steps of stacking a plurality of laminations (11 , 14) over one another, wherein the laminations (11 , 14) each have a ring shaped base structure (20) with recesses (21 ), wherein the recesses (21 ) open to an inner edge (D) or outer edge (E) of the base structure (20) and have inner lamination regions (G) and lamination edge regions (H), each of which is arranged adjacent to one of the inner lamination regions (G) where the recesses (21 ) open, thereby forming- a plurality of inner stack regions (B), which are formed by interconnected ones of the inner lamination regions (G) and which are provided for accommodating windings (12, 15) or magnets, and- a plurality of stack edge regions (C), which are formed by interconnected ones of the lamination edge regions (H), andarranging a plurality of stack pipes (16) in the lamination stack (10, 13), each of which runs in one of the stack edge regions (C).

14. Method of manufacturing a lamination stack (10, 13) for an electric machine (1 ), comprising the steps of forming a plurality of laminations (11 , 14), each having a ring shaped base structure (20) with recesses (21 ), wherein the recesses (21 ) open to an inner edge (D) or outer edge (E) of the base structure (20) and have inner lamination regions (G) and lamination edge regions (H), each of which is arranged adjacent to one of the inner lamination regions (G) where the recesses (21 ) open, forming annular structures (22), each in one of the lamination edge regions (H), stacking a plurality of laminations (11 , 14) over one another, thereby forming- a plurality of inner stack regions (B), which are formed by interconnected ones of the inner lamination regions (G) and which are provided for accommodating windings (12, 15) or magnets,- a plurality of stack edge regions (C), which are formed by interconnected ones of the lamination edge regions (H), and- a plurality of stack pipes (16), which are formed by interconnected ones of the annular structures (22) in the stack edge regions (C).

15. Method according to claim 14, characterized in that the laminations (11 , 14) are glued together at least in the lamination edge regions (H), wherein a) in a first step, the laminations (11 , 14) each are coated with a first component of a two component glue after the annular structures (22) have been formed but before stacking the laminations (11 , 14) over one another, in a second step, a second component of the two component glue is applied to the first component, and in a third step, the laminations (11 , 14) are stacked over one another before the two component glue hardens or b) in a first step, the laminations (1 1 , 14) each are coated with a thermoplastic material after the annular structures (22) have been formed but before stacking the laminations (11 , 14) over one another, in a second step, the laminations (1 1 , 14) are stacked over one another, and in a third step, the lamination stack (10, 13) is heated above a melting temperature of the thermoplastic material.

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