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

Abstract

A lamination sheet (11, 14) for a lamination stack (10, 13) of an electric machine (1) is disclosed. The lamination sheet (11, 14) comprises a ring shaped base section (15) of soft iron with recesses (16) for accommodating a winding (12) of the electric machine (1), wherein the base section (15) is made by printing and sintering a soft iron base material. Moreover, the lamination sheet (11, 14) comprises an edge section (17) of an insulating material adjacent to the base section (15) in the region of the recesses (16), which is made by printing and sintering an insulating base material. Further on, a lamination stack (10, 13) with such lamination sheets (11, 14), an electric machine (1) with such a lamination stack (10, 13), a vehicle with such an electric machine (1) and methods of manufacturing lamination sheets (11, 14) for a lamination stack (10, 13) and of manufacturing a lamination stack (10, 13) are disclosed.

Description

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

[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 base section of soft iron with recesses for accommodating a winding of the electric machine and wherein the base section is made by printing and sintering a soft iron base material. Moreover, the invention relates to a lamination stack, which comprises a plurality of lamination sheets of the above kind being stacked over one another. In addition, the invention relates to an electric machine, which comprises a stator and a rotor, which is rotatably relative to the stator, wherein the stator has a stator lamination stack of the above kind and / or wherein the rotor has a rotor lamination stack of the above kind. Further on, the invention relates to a vehicle, which is driven by an electric machine as defined above. Finally, the invention relates to methods of manufacturing a lamination sheet for a lamination stack of an electric machine and of manufacturing a lamination stack with such lamination sheet.

[0004] BACKGROUND ART

[0005] A lamination sheet, a lamination stack, an electric machine, a vehicle and methods of the above kinds are known in prior art. Generally, a slot insulation is placed in the stack slots of the lamination stack before the windings of the electric machine are made. In this way, the windings are electrically insulated from the lamination stack. Often, dedicated folded paper sheets or dedicated plastic parts are used for this purpose. Unfortunately, attaching these insulation parts complicates the manufacturing process of the electric machine and makes the same time consuming. Moreover, producing the desired insulation parts takes an extra process step before assembling the electric machine. In case that different types of electric machines shall be produced, different insulation parts have to be produced and have to be held on stock.

[0006] DISCLOSURE OF INVENTION Accordingly, an object of the invention is to provide an improved lamination sheet, an improved lamination stack, an improved electric machine, an improved vehicle and improved methods of making lamination sheets and a lamination stack. In particular, a solution shall be proposed, which eases the manufacturing process of the electric machine and makes the production faster.

[0007] The object of the invention is solved by a lamination stack as disclosed in the opening paragraph, additionally comprising an edge section of an insulating material adjacent to the base section in the region of the recesses, which is made by printing and sintering an insulating base material.

[0008] Moreover, 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] For example, the lamination stack a) can be embodied as a stator lamination stack, wherein the edge section is arranged radially inwards of the base section in case of an internal rotor machine or arranged radially outwards of the base section in case of an external rotor machine or b) is embodied as a rotor lamination stack, wherein the edge section is arranged radially outwards of the base section in case of an internal rotor machine or arranged radially inwards of the base section in case of an external rotor machine.

[0010] Further on, the invention is solved by an electric machine comprising a stator and a rotor, which is rotatably relative to the stator, wherein the stator comprises a stator lamination stack according to case a) of the aforementioned kind and / or wherein the rotor comprises a rotor lamination stack according to case b) of the aforementioned 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] Furthermore, 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 base section with recesses for accommodating a winding of the electric machine, printing with an insulating base material an edge section adjacent to the base section in the region of the recesses 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 base section and the edge section can be printed in any desired order. In particular, the base section can be printed first and then the edge section can be printed.

[0014] The invention is also solved by an alternative 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 base section with recesses for accommodating a winding of the electric machine, heating and sintering the base section, printing with an insulating base material an edge section adjacent to the base section in the region of the recesses and heating and sintering the edge section.

[0015] Here, heating and sintering the sections of the lamination sheet is done in two steps. That means, in a first step, the base section is printed and then heated and sintered, and in a second step, the edge section is printed and then heated and sintered. Accordingly, the base section is already solid when the edge section is printed.

[0016] Finally, the invention is 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 one of the methods of the above kind and interconnecting the edge sections of the plurality of lamination sheets by heating the same up to the melting point of the insulating material at least locally.

[0017] By the proposed measures, an insulation for the lamination stack is produced in line with the production of the lamination sheets and no extra parts need to be produced and held on stock. Accordingly, the manufacturing process of the electric machine is eased and made faster. In an advantageous embodiment, the base section and / or the edge section is / are printed by means of a screen printing method. In this way, the base section and / or the edge section can be printed very fast. For example, the base section is printed in a first step and the edge section is printed in a second step. However, it is also possible to print the base section and / or the edge section by means of a jet printing method. Also mixed embodiments are possible. For example, the base section can be printed by use of a screen printing method (in particular in a first step) and the edge section can be printed by use of a jet printing method (in particular in a second step).

[0018] Preferably, the insulating material can contain or consist of plastic, ceramic, glass or paper. Accordingly, the insulating base material can contain or consist of plastic, ceramic, glass or paper, too. All these materials may be printed and provide good to very good electric insulation. Some of them may be melted, for example ceramic, glass and thermoplastic. If heating and sintering the sections of the lamination sheet is done at once, it is of advantage if the melting points of the soft iron and the insulation material are similar. Accordingly, it is of advantage to use an insulation material containing or consisting of ceramic and / or glass then.

[0019] In case that the edge sections of the plurality of lamination sheets are interconnected by heating the same up to the melting point of the insulating material at least locally, moreover, the stability of the lamination stack and the insulation capability of the edge sections can be improved. In fact, the interconnected edge sections form a kind of an insulation shell. In particular, the edge sections of the plurality of lamination sheets can be interconnected by means of laser welding.

[0020] Further on, it is very advantageous if heating and sintering the base section is done by means of induction heating and heating and sintering the edge section is done by means of heat transfer from the base section to the edge section. In this way, the magnetic conduction of the soft iron is used to concentrate the heat to the base section so as to distinctively melt the soft iron particles in the base section. In contrast, the insulation material of the edge section is not actively heated but melt by heat transfer from the base section to the edge section. In some embodiments, the melting point of the soft iron may be considerably higher than the melting point of the insulation material. However, by the proposed measures, both the soft iron and the insulation material can be sintered in a very good way and without overheating the insulation material and without underheating the soft iron.

[0021] BRIEF DESCRIPTION OF DRAWINGS

[0022] The invention now is described in more detail hereinafter with reference to particular embodiments, which the invention however is not limited to.

[0023] Fig. 1 shows a half sectional view of an exemplary electric machine;

[0024] Fig. 2 shows a front view of an exemplary lamination;

[0025] Fig. 3 shows a detailed view of the lamination of Fig. 1 and

[0026] Fig. 4 shows a schematic view of an electric vehicle.

[0027] DETAILED DESCRIPTION

[0028] 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.

[0029] Fig. 1 shows a schematic cross sectional view of an exemplary electric machine 1 . The electric machine 1 comprises a rotor shaft 2 with a rotor 3 mounted thereon, wherein the rotor shaft 2 is rotatably supported in (roller)bearings 4a, 4b around a rotor axis RA and relative to a stator 5 of the electric machine 1 . Moreover, the electric machine 1 comprises a first bearing shield 6, in which the first bearing 4a is arranged, a second bearing shield 7, in which the second bearing 4b is arranged, and a stator housing 8, in which the stator 5 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.

[0030] The stator 5 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 RA respectively. Further on, the stator 5 comprises stator windings 12 arranged in the stator lamination stack 10. The rotor 3 comprises a rotor lamination stack 13 with a plurality of rotor laminations 14 stacked over one another along the rotor axis RA. In addition, the rotor 3 comprises rotor windings or rotor magnets (both not shown) arranged in the rotor lamination stack 13.

[0031] 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 15 of soft iron with recesses 16 for accommodating the stator windings 12, wherein the recesses 16 open to an inner edge B or outer edge C of the base structure 15. The base section 15 is made by printing and sintering a soft iron base material.

[0032] Figs. 3 shows a detailed view of the stator lamination 11 of Fig. 2. As can be seen, the stator lamination 11 comprises an edge section 17 of an insulating material adjacent to the base section 15 in the region of the recesses 16. The edge section 17 is made by printing and sintering an insulating base material.

[0033] A method of manufacturing a stator lamination sheet 1 1 can comprise the following steps: printing with a soft iron base material the ring shaped base section 15 with recesses 16 for accommodating a stator winding 12 of the electric machine 1 , printing with an insulating base material the edge section 17 adjacent to the base section 15 in the region of the recesses 16 and heating and sintering the lamination sheet 11 .

[0034] Here, heating and sintering the sections 15, 17 of the stator lamination sheet 11 is done at once. That means, first, all sections 15, 17 are printed and then all sections 15, 17 are heated and sintered at once. The base section 15 and the edge section 17 can be printed in any desired order. In particular, the base section 15 can be printed first and then the edge section 17 can be printed.

[0035] An alternative method of manufacturing a stator lamination sheet 11 can comprise the following steps: printing with a soft iron base material the ring shaped base section 15 with recesses 16 for accommodating a stator winding 12 of the electric machine 1 , heating and sintering the base section 15, printing with an insulating base material the edge section 17 adjacent to the base section 15 in the region of the recesses 16 and heating and sintering the edge section 17.

[0036] Here, heating and sintering the sections 15, 17 of the stator lamination sheet 11 is done in two steps. That means, in a first step, the base section 15 is printed and then heated and sintered, and in a second step, the edge section 17 is printed and then heated and sintered. Accordingly, the base section 15 is already solid when the edge section 17 is printed.

[0037] Generally, any applicable printing method can be used for printing the base section 15 and the edge section 17. In an advantageous embodiment, the base section 15 and / or the edge section 17 is / are printed by means of a screen printing method. In this way, the base section 15 and / or the edge section 17 can be printed very fast. For example, the base section 15 is printed in a first step and the edge section 17 is printed in a second step. However, it is also possible to print the base section 15 and / or the edge section 17 by means of a jet printing method. Also mixed embodiments are possible. For example, the base section 15 can be printed by use of a screen printing method (in particular in a first step) and the edge section 17 can be printed by use of a jet printing method (in particular in a second step).

[0038] Preferably, the insulating material can contain or consist of plastic, ceramic, glass or paper. Accordingly, the insulating base material can contain or consist of plastic, ceramic, glass or paper, too. All these materials may be printed and provide good to very good electric insulation. Some of them may be melted, for example ceramic, glass and thermoplastic.

[0039] It is very advantageous if heating and sintering the base section 15 is done by means of induction heating and heating and sintering the edge section 17 is done by means of heat transfer from the base section 15 to the edge section 17. In this way, the magnetic conduction of the soft iron is used to concentrate the heat to the base section 15 so as to distinctively melt the soft iron particles in the base section 15. In contrast, the insulation material of the edge section 17 is not actively heated but melt by heat transfer from the base section 15 to the edge section 17. In some embodiments, the melting point of the soft iron may be considerably higher than the melting point of the insulation material. However, by the proposed measures, both the soft iron and the insulation material can be sintered in a very good way and without overheating the insulation material and without underheating the soft iron. Generally, a stator lamination stack 10 can be made by simply by stacking a plurality of lamination sheets 1 1 over one another. However, it is advantageous if the edge sections 17 of the plurality of stator lamination sheets 1 1 are interconnected by heating the same up to the melting point of the insulating material at least locally. In this way, the stability of the stator lamination stack 10 and the insulation capability of the edge sections 17 can be improved. In fact, the interconnected edge sections 17 form a kind of an insulation shell. In particular, the edge sections 17 of the plurality of stator lamination sheets 1 1 can be interconnected by means of laser welding.

[0040] 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. Hence, the rotor 3 of the electric machine 1 can comprise such a (rotor) lamination stack 13. 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”.

[0041] Generally, in case of a stator lamination stack 10, the edge section 17 can be arranged radially inwards of the base section 15 for an internal rotor machine or arranged radially outwards of the base section 15 for an external rotor machine. In case of rotor lamination stack 13, the edge section 17 can be arranged radially outwards of the base section 15 for an internal rotor machine or arranged radially inwards of the base section 15 for an external rotor machine.

[0042] By the proposed measures, an insulation for the lamination stack 10, 13 can be produced in line with the production of the lamination sheets 11 , 14 and no extra parts need to be produced and held on stock. Accordingly, the manufacturing process of the electric machine 1 is eased and made faster.

[0043] Fig. 4 finally shows an electric vehicle 18 with an electric machine 1 as defined hereinbefore, which is provided to propel the electric vehicle 18. In detail, the electric machine 1 is coupled to an optional gearbox 19, side shafts 20 and finally to the wheels 21 . The electric machine 1 may be provided for powering the electric vehicle 18 permanently in a pure electric car or intermittently, e.g. in combination with a combustion engine in a hybrid car.

[0044] 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 18 may have more or less parts than shown in the figures. It is also noted that the electric machine 1 and the electric vehicle 18 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 19 is not mandatory, and the electric vehicle 18 may be propelled by the electric machine 1 solely.

[0045] 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 as- sociation 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.

[0046] List of References

[0047] 1 electric machine

[0048] 2 rotor shaft

[0049] 3 rotor

[0050] 4a, 4b bearing

[0051] 5 stator

[0052] 6 first bearing shield

[0053] 7 second bearing shield

[0054] 8 stator housing

[0055] 9 machine housing

[0056] 10 lamination stack (stator lamination stack)

[0057] 11 lamination sheet (stator lamination sheet)

[0058] 12 stator winding

[0059] 13 lamination stack (rotor lamination stack)

[0060] 14 lamination sheet (rotor lamination sheet)

[0061] 15 base section

[0062] 16 recess

[0063] 17 edge section

[0064] 18 vehicle

[0065] 19 gearbox

[0066] 20 side shaft

[0067] 21 wheel

[0068] RA axis (rotor axis / stator axis)

[0069] B inner edge of ring structure

[0070] C outer edge of ring structure

Claims

Claims1. Lamination sheet (11 , 14) for a lamination stack (10, 13) of an electric machine (1), comprising a ring shaped base section (15) of soft iron with recesses (16) for accommodating a winding (12) of the electric machine (1 ), wherein the base section (15) is made by printing and sintering a soft iron base material, characterized in an edge section (17) of an insulating material adjacent to the base section (15) in the region of the recesses (16), which is made by printing and sintering an insulating base material.

2. Lamination sheet (11 , 14) according to claim 1 , characterized in that the insulating material contains or consists of plastic, ceramic, glass or paper.

3. Lamination stack (10, 13), comprising a plurality of lamination sheets (11 , 14) according to any one of the claims 1 to 2 being stacked over one another.

4. Lamination stack (10, 13) according to claim 3, characterized in that the lamination stack (10, 13) a) is embodied as a stator lamination stack (10), wherein the edge section (17) is arranged radially inwards of the base section (15) in case of an internal rotor machine or arranged radially outwards of the base section (15) in case of an external rotor machine or b) is embodied as a rotor lamination stack (13), wherein the edge section (17) is arranged radially outwards of the base section (15) in case of an internal rotor machine or arranged radially inwards of the base section (15) in case of an external rotor machine.

5. Electric machine (1 ) comprising a stator (5) and a rotor (3), which is rotatably relative to the stator (5), characterized in that the stator (5) comprises a stator lamination stack (10) according to case a) of claim 4 and / or the rotor (3) comprises a rotor lamination stack (13) according to case b) of claim 4.

6. Vehicle (18), driven by an electric machine (1) as claimed in claim 5.

7. Method of manufacturing a lamination sheet (11 , 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 base section (15) with recesses (16) for accommodating a winding (12) of the electric machine (1 ), printing with an insulating base material an edge section (17) adjacent to the base section (15) in the region of the recesses (16) and heating and sintering the lamination sheet (11 , 14).

8. Method of manufacturing a lamination sheet (11 , 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 base section (15) with recesses (16) for accommodating a winding (12) of the electric machine (1 ), heating and sintering the base section (15), printing with an insulating base material an edge section (17) adjacent to the base section (15) in the region of the recesses (16) and heating and sintering the edge section (17).

9. Method as claimed in claim 7 or 8, characterized in that the base section (15) and / or the edge section (17) is / are printed by means of a screen printing method.

10. Method as claimed in any one of claims 7 to 9, characterized in that heating and sintering the base section (15) is done by means of induction heating and heating and sintering the edge section (17) is done by means of heat transfer from the base section (15) to the edge section (17).11 . Method of manufacturing a lamination stack (10, 13) for an electric machine (1 ), comprising the steps stacking a plurality of lamination sheets (11 , 14) according to any one of claims 1 or 2 or stacking a plurality of lamination sheets (11 , 14) made by a method according to any one of claims 7 to 10 and interconnecting the edge sections (17) of the plurality of lamination sheets (11 , 14) by heating the same up to the melting point of the insulating material at least locally.

12. Method according to claim 1 1 , characterized in that the edge sections (17) of the plurality of lamination sheets (11 , 14) are interconnected by means of laser welding.

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