Electric drive for vehicle and method for producing electric drive for vehicle

Abstract

An electric drive (1) for a vehicle (100), the electric drive (1) comprising:-a stator (3) comprising a stator winding (5) and a stator core (6) having a longitudinal axis (7) and opposite axial first and second face sides (8, 9), the stator winding (5) forming a first winding head (10) on the first face side (8) and a second winding head (11) on the second face side (9); -a housing (12) having an interior (13) forming a stator receiving space (14) and a radial stop (15) axially delimiting the stator receiving space (14); and-a spacer (26) attached to the first face side (8) at a radial position further outward than the first winding head (10) and abutting against the stop (15).

Description

TECHNICAL FIELD

[0001] The invention relates to an electric drive for a vehicle, comprising a stator comprising stator windings and a stator core having a longitudinal axis and opposite axial first and second face sides, the stator windings forming a first winding head at the first face side and a second winding head at the second face side, and a housing having an interior forming a stator accommodation space and a radial stop axially delimiting the stator accommodation space.

[0002] Further, the invention relates to a method for manufacturing an electric drive for a vehicle. BACKGROUND

[0003] Electric drives for propelling a vehicle are well known. Therein, it is known to arrange an electric machine of the electric drive within a housing.

[0004] Exemplarily, EP 3 972 098 A1 discloses an arrangement for an electric machine. The electric machine comprises a housing with a stop to define an axial position of a stator within the housing. The stator is arranged in the housing and comprises a stator lamination stack, stator windings arranged in the stator lamination stack and stator end discs arranged on axial end portions of the stator lamination stack.

[0005] Conventional electric drives are configured such that the stator exactly fits into the stator accommodation space, which is limited by the stop. This requires a dedicated housing to be designed for each stator used in the electric drive.

[0006] It is an object of the invention to provide a more variable design of an electric drive for a vehicle. SUMMARY

[0007] According to the invention, the object is achieved by an electric drive for a vehicle as initially described, further comprising a spacer attached to the first face side at a radial position further outward than the first winding head and abutting against the stop.

[0008] The electric drive for a vehicle according to the invention comprises a stator. The stator comprises stator windings and a stator core. The stator core has a longitudinal axis. The stator core has opposite axial first and second face sides. The stator windings form a first winding head at the first face side. The stator windings form a second winding head at the second face side. The electric drive for a vehicle according to the invention further comprises a housing having an interior. The interior forms a stator accommodation space. The interior forms a radial stop. The stop axially delimits the stator accommodation space. The electric drive for a vehicle according to the invention further comprises a spacer. The spacer is attached to the first face side at a radial position further outward than the first winding head. The spacer abuts against the stop.

[0009] The present invention is based on the consideration of using a housing of an electric drive for different sizes of stators. Therein, a spacer adapts the length of the stator to the length of the stator accommodation space. Thus, the electric drive according to the present invention is provided with a single housing design which is able to accommodate stators with different lengths without having to design a dedicated housing for the respective stator length. This reduces the costs for manufacturing electric drives of different power classes and simplifies the manufacturing process since only a single type of housing has to be provided. As an additional advantage, the use of a spacer allows for arranging stators of different lengths in the vicinity of a given center of mass of the electric drive.

[0010] In particular, the terms "axial", "radial" and "circumferential" refer to a longitudinal axis of the stator core.

[0011] Preferably, the stator winding is a hairpin winding. The stator can be made of a plurality of axially stacked metal sheets.

[0012] The housing can be made of metal. The housing can be a cast housing. The stator accommodation space can be a cylindrical space radially defined by a wall of the housing. The stator accommodation space can be open on one or both axial sides thereof. The stopper can extend circumferentially around the longitudinal axis. Alternatively, the stopper can be formed at one or more circumferentially separated locations. Typically, the stopper forms an integral part of the housing.

[0013] The housing can comprise a main part forming the stator accommodation space. The housing can further comprise an end cover configured to bound the stator accommodation space on a side thereof opposite to the stopper. The end cover can be fastened to the main part.

[0014] The spacer can be made of an electrically insulating material. Preferably, the spacer is made of a polymer. The spacer can be made by injection molding.

[0015] In another embodiment, the spacer is made of aluminum.

[0016] Preferably, the spacer is formed annularly around the longitudinal axis. In particular, the spacer is formed as a single piece.

[0017] Preferably, the housing forms a coolant inlet for supplying coolant into the interior of the housing for cooling the stator. The coolant can be water, oil, coolant or a gaseous fluid. The electric drive can comprise a pump device configured to deliver the coolant along a closed cooling circuit to the inlet.

[0018] The electric drive device according to the application can further comprise a first oil jet ring attached to the first face side of the stator core at a radial position between the first winding head and the spacer, such that the spacer and the first oil jet ring radially delimit a first fluid chamber fluidically connected to the inlet. Therein, the first oil jet ring can be configured to jet coolant from the first fluid chamber towards the first winding head. This allows to achieve a jet cooling of the first winding head for effectively dissipating heat therefrom during operation of the electric drive device.

[0019] In particular, the first oil jet ring is provided with a plurality of nozzles allowing a flow of coolant from the first fluid chamber to the first winding head. The nozzles can be distributed circumferentially around the longitudinal axis.

[0020] The first oil jet ring can be made of an electrically insulating material. Preferably, the first oil jet ring is made of a polymer. The first oil jet ring can be made by injection molding.

[0021] In another embodiment, the first oil jet ring is made of aluminum.

[0022] According to a preferred design, the housing and the stator core radially delimit a cooling jacket fluidically connected to the inlet and configured to guide coolant along the outer circumference of the stator core. This allows to effectively dissipate heat from the stator core during operation of the electric drive device.

[0023] It is very preferred that the spacer comprises an opening fluidically connecting the first fluid chamber and the cooling jacket. Thus, the spacer adapts the axial extent of the cooling jacket to the length of the stator and allows to supply coolant from the cooling jacket into the first fluid chamber.

[0024] The spacer can comprise two annular protrusions axially spaced apart and axially delimiting the first fluid chamber. Further, the interior of the housing can form two annular protrusions corresponding to the protrusions of the first oil jet ring and arranged at an axial position outside the stop from the stator. Therein, the protrusions formed by the housing can delimit the first fluid chamber when a longer stator is arranged in the stator accommodation space. In other words, the protrusions of the spacer mimic the protrusions formed by the housing for a smaller stator in the electric drive device according to the application.

[0025] The electric drive device can further comprise a second oil jet ring attached to the second face side of the stator core at a radial position radially further out than the second winding head, such that the housing and the second oil jet ring radially delimit a second fluid chamber fluidically connected to the inlet. Therein, the second oil jet ring can be configured to jet coolant from the second fluid chamber towards the second winding head. This allows to effectively dissipate heat from the second winding head.

[0026] In particular, the axial extent of the second oil jet ring can be chosen such that the second oil jet ring adapts the length of the stator to the axial extent of the stator accommodation space.

[0027] Preferably, the cooling jacket and the second fluid chamber are connected in a fluid conducting manner.

[0028] The electric drive arrangement according to the application can further comprise an inverter arranged in an inverter accommodation space formed by the housing on a side opposite to the stator accommodation space. Such an electric drive arrangement provides an integrated solution for propelling a vehicle. The inverter accommodation space is formed by the main portion of the housing. The housing can further comprise an inverter cover fastened to the main portion for closing the inverter accommodation space.

[0029] Further, the electric drive arrangement can further comprise a rotor forming an electric machine together with the stator. The electric machine can be a permanent or electrically excited motor or an induction motor. The electric drive arrangement can further comprise a rotor shaft connected to the rotor in a torsionally rigid manner. Further, the electric drive arrangement can comprise an output shaft and a gear box mechanically coupling the rotor shaft with the output shaft. The gear box can be arranged in the housing. The housing can further comprise a gear box cover fastened to the main portion on a side opposite to the end shield.

[0030] The above object is also solved by a method for manufacturing an electric drive arrangement for a vehicle, the method comprising the steps of: providing a stator comprising stator windings and a stator core having a longitudinal axis and opposite axial first and second face sides, the stator windings forming a first winding head at the first face side and a second winding head at the second face side; providing a housing having an interior forming a stator accommodation space and a radial stop axially delimiting the stator accommodation space; evaluating whether an axial length of the stator core lies within at least one of at least two predetermined ranges; attaching a spacer to the first face side at a radial position further outward than the first winding head if the axial length lies within at least one of the at least two ranges; and arranging the stator in the stator accommodation space such that the spacer abuts against the stop if the axial length lies within at least one of the at least two ranges, and such that the first face side abuts against the stop otherwise.

[0031] The method can comprise the further steps of: evaluating in which one of a plurality of predetermined stator ranges the length of the stator core lies; and attaching a second oil jet ring to the second face side of the stator core at a radial position further outward than the second winding head, wherein a first type of second oil jet ring having a first oil ring length is used if the axial length lies within a first sub-range, and a second type of second oil jet ring having a second oil ring length smaller than the first axial length is used if the axial length lies within a second sub-range.

[0032] Preferably, in the step of attaching the second oil spray ring, if the axial length is within the third sub-range, a third type of second oil ring having a third oil ring length smaller than the second oil ring length is used.

[0033] The method may further comprise the steps of selecting an end shield from the group of first to nth types of end shields based on the evaluation of the subranges, and closing the stator receiving space by the selected end shield, wherein n corresponds to the number of subranges.

[0034] The above object is also achieved by a vehicle comprising an electric drive device according to the invention or an electric drive device obtained by the manufacturing method according to the invention, the electric drive device being configured to propel the vehicle.

[0035] The vehicle may be a battery electric vehicle (BEV). Alternatively, the vehicle may be a hybrid vehicle and also include an internal combustion engine.

[0036] All statements regarding the electric drive according to the invention apply analogously to the method according to the invention, so that the advantages described above can also be achieved with this method. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Further details and advantages of the present invention are described in the following embodiments with reference to the accompanying drawings. The drawings schematically show:

[0038] Figure 1 is a schematic diagram of an embodiment of an electric drive device according to the present invention;

[0039] Figure 2 is a partial view of a housing according to this embodiment;

[0040] Figure 3 is a perspective view of a stator and a spacer according to this embodiment;

[0041] Figure 4 is a cross-sectional view of the electric drive device according to this embodiment;

[0042] Figure 5 is a flow chart of an embodiment of a manufacturing method according to the present invention;

[0043] Figure 6 is a schematic diagram of an electric drive device obtained by an embodiment of the method; and

[0044] Figure 7 is a schematic diagram of an embodiment of a vehicle according to the present invention. DETAILED DESCRIPTION

[0045] Figure 1 1 is a schematic diagram of an embodiment of an electric drive device 1 .

[0046] The electric drive 1 comprises an electric machine 2 with a stator 3 and a rotor 4. The electric machine 2 can be a permanent or electrically excited synchronous machine or an induction machine.

[0047] The stator 3 comprises a stator winding 5 and a stator core 6. The stator core 6 has a longitudinal axis 7 and opposite axial first and second face sides 8, 9. In Figure 1 The stator winding 5, only partly visible in the figure, forms a first winding head 10 at the first face side 8 and a second winding head 11 at the second face side 9.

[0048] In particular, the stator core 3 is made of a plurality of stacked metal sheets which are electrically insulated from each other. In more detail, the stator winding 5 is exemplarily formed as a hairpin winding, wherein the first winding head 10 comprises a soldered connection of the respective hairpin-shaped conductors forming the stator winding 5. Accordingly, the second winding head 11 is formed by the bent head portions of the hairpin conductors.

[0049] The electric drive 1 further comprises a housing 12. An interior 13 of the housing 12 forms a stator accommodation space 14 and a radial stop 15 (see Figure 2 ), which axially bounds the stator accommodation space 14.

[0050] As an exemplary design, the housing 12 comprises a main portion 16 forming the stator accommodation space 14 and an end cover 17 which is fastened to the main portion 16. The end cover 17 bounds the stator accommodation space 14 at its side opposite to the stop 15.

[0051] As a further component, the electric drive 1 comprises an inverter 18 which is arranged in an inverter accommodation space 19 formed by the main portion 16 of the housing 12 at a side opposite to the stator accommodation space 14. The inverter accommodation space 19 is closed by a cover 20 of the housing 12.

[0052] Further, Figure 1 A rotor shaft 21 extending along the longitudinal axis 7 is shown, which is coupled to the rotor 4 in a torsionally rigid manner and is supported by the end cover 17. The rotor shaft 21 is coupled to an output shaft 22 of the electric drive 1 by means of a gear box 23. The gear box 23 is arranged in the main portion 16 and faces the first face side 8 of the stator 6. The main portion 16 is closed by a gear box cover 24 of the housing 12.

[0053] Figure 2 is a partial view of the housing 12 according to the embodiment, wherein the main portion 16 is shown.

[0054] It can be seen that the stator accommodation space 14 is a cylindrical space which is radially delimited by a wall 25 of the housing 12 or its main portion 16, respectively. The stator accommodation space 14 is open at both of its axial sides. The stop 15 is formed at a plurality of circumferentially spaced-apart locations, three of which are Figure 2visible in the radial direction and form an integral part of the housing 12.

[0055] Figure 3 is a perspective view of the stator 6 and the spacer 26 according to the embodiment. Figure 4 is a partial sectional view of the electric drive 1.

[0056] The spacer 26 forms part of the electric drive 1 and is attached to the first face side 8 of the stator core 6 (hidden in Figure 3 ) at a radial position further out than the first winding head 10 (hidden in Figure 3 ) and abuts against the stop 15, which is best shown in Figure 4 . Thus, the spacer 26 adapts the length of the stator 3 to the length of the stator accommodation space 14, allowing for a variable length of the stator to be arranged within the housing 12.

[0057] As best shown in Figure 3 , the spacer 26 is formed annularly around the longitudinal axis 7. In detail, the spacer 26 is formed as a single piece made of electrically insulating polymer. In particular, the spacer 26 is made by injection molding. But in another embodiment, the spacer 26 can be formed as a single piece made of aluminum.

[0058] The electric drive 1 according to the present embodiment is additionally provided with a stator cooling arrangement. Further, the housing 12 forms a coolant inlet (not shown) for supplying coolant into the interior 13 of the housing 12 for cooling the stator 3. The inlet is formed as an opening in the wall 25 of the housing 12 and allows for supplying fluid, e.g. oil, water, coolant or gaseous coolant, to the stator 3.

[0059] As part of the stator cooling arrangement, a cooling jacket 27 is provided, which is radially delimited by the housing 12 or its main portion 16, respectively, and the stator core 6. The cooling jacket 27 is fluidically connected to the inlet and is configured to guide coolant along the outer circumference of the stator core 6. That is, the coolant flows circumferentially around the outer circumference of the stator core 6 for dissipating heat generated inside the stator 3.

[0060] As another part of the stator cooling, the electric drive 1 comprises a first oil jet ring 28, which is attached to the first face side 8 of the stator core 6 at a radial position between the first winding head 10 and the spacer 26, such that the spacer 26 and the oil jet ring 28 radially delimit a first fluid chamber 29. The first oil jet ring 28 is configured to jet coolant from the first fluid chamber 29 towards the first winding head 10. To this end, the first oil jet ring 28 is provided with a plurality of nozzles 30, one of which is visible in Figure 4 . The nozzles 30 are distributed circumferentially in the first oil jet ring 28.

[0061] As best shown in Figure 3Best shown, the spacer 26 comprises a plurality of openings 31, two of which are hidden in Figure 3 Each opening 31 fluidically connects the first fluid chamber 29 and the cooling jacket 27, such that coolant can be supplied from the inlet into the first fluid chamber 29.

[0062] As Figure 4 Best shown, the spacer 26 comprises two annular protrusions 32, 33, which are axially spaced apart and axially delimit the first fluid chamber 29. The interior 13 of the housing 12 forms two annular protrusions 34, 35, which correspond to the protrusions 32, 33 of the first oil jet ring 28. From the stator 3, the protrusions 34, 35 are arranged in an axial position outside the stop 15. When a stator is provided to the housing 12, which is longer than the stator 3 of the present embodiment, the stator can directly abut against the stop 15. In this case, the protrusions 34, 35 in the housing 12 serve as axial limits for the respective first fluid chamber.

[0063] Again referring to Figure 1 , the electric drive 1 comprises a second oil jet ring 36, which is attached to the second face side 9 of the stator core 6 at a radial position radially further out than the second winding head 11, such that the housing 12 and the second oil jet ring 36 radially delimit a second fluid chamber 37, which is fluidically connected to the inlet. The second oil jet ring 36 is configured to jet coolant from the second fluid chamber 37 towards the second winding head 11 and can be provided with similar nozzles as the first oil jet ring 28. Correspondingly, the cooling jacket 27 and the second fluid chamber 37 are fluidically connected.

[0064] To supply coolant into the inlet, the electric drive 1 is provided with a pump device 38, which is schematically shown in Figure 1 The inlet, the cooling jacket 27 and the fluid chambers 29, 37 can form part of a closed cooling circuit, in which the pump device 38 transports coolant.

[0065] In the following, embodiments of a method for manufacturing an electric drive are described in detail. The electric drive 1 according to the above-described embodiments can be obtained by the manufacturing method. For the sake of simplicity, the same or equivalent components used in the manufacturing method have the same reference signs as in the above-described embodiments of the electric drive 1.

[0066] Figure 5 is a flow chart of an embodiment of the manufacturing method. Figure 6 Five principle sketches of the electric drive 1 obtained by the embodiment of the method are shown. Therein, Figure 6 The five stators 3 with different lengths L1 to L5 are schematically shown, which L1 < L2 < L3 < L4 < L5 of their respective stator cores 6.

[0067] The method comprises a step S1 of providing a stator 3. The stator 3 comprises a stator winding 5 and a stator core 6 having a longitudinal axis 7 and opposite axial first and second face sides 8, 9. The stator winding 5 forms a first winding head 10 on the first face side 8 and a second winding head 11 on the second face side 9.

[0068] The method comprises a further step S2 of providing a housing 12 having an interior 13 forming a stator accommodation space 14 and a radial stop 15 axially delimiting the stator accommodation space 14.

[0069] The method comprises a further step S3 of assessing whether the axial length of the stator core 6 lies within one of two predetermined ranges. The range R1 covers the lengths LI and L2. The other range R2 covers the lengths L3, L4 and L5. Further, each range R1, R2 is subdivided into three sub-ranges SR1, SR2, SR3. In the range R1, the sub-range SR1 covers the length LI, the sub-range SR2 covers the length L2. In the range R2, the sub-range SR1 covers the length L3, the sub-range SR2 covers the length L4, and the sub-range SR3 covers the length L5. Note that in this particular embodiment, no length is assigned to the sub-range SR3 in the R1 range.

[0070] In a subsequent step S4, if the axial length is within the range R1, a spacer 26 is attached to the first face side 8. The spacer 26 is attached to the first face side 8 at a radial position further outwards than the first winding head 10.

[0071] After step S4, or in case the assessment of step S3 leads to a length lying within the range R2, the method comprises a further step S5 of assessing in which one of the predetermined sub-ranges SR1, SR2, SR3 the axial length of the stator core 6 lies.

[0072] Depending on the result of the assessment in step S5, in a subsequent step S6, a second oil ring 36, 36', 36" is attached to the second face side 9 of the stator core 6 at a radial position radially further outwards than the second winding head 11. If the axial length lies within the sub-range SR1, a first type of second oil ring 36 having a first oil ring length is used. If the axial length lies within the sub-range SR2, a second type of second oil ring 36' having a second oil ring length smaller than the first oil ring length is used. If the axial length lies within the sub-range SR3, a third type of second oil ring 36" having a third oil ring length smaller than the second oil ring length is used.

[0073] In a subsequent step S7, the stator 3 is arranged into the stator accommodation space 14. Therein, the stator 3 is arranged in the stator accommodation space 14 such that, if - depending on the evaluation in step S3 - the axial length L1, L2 lies in the range R1, the spacer 26 abuts against the stop 15. If the axial length L3, L4, L5 lies in the range R2, the stator 3 is arranged in the stator accommodation space 14 such that the first face side 8 abuts against the stop 15.

[0074] In a subsequent step S8, the end shield 17 is selected from the group of first, second and third type end shields 17 and arranged at the main portion 16 for closing the stator accommodation space 14, depending on the evaluation of the sub-ranges SR1, SR2, SR3 (see step S5). That is, depending on the type of the second oil jet ring 36, 36’, 36”, a suitable type of end shield 17 is selected for forming the second fluid chamber 37.

[0075] Figure 7 is a schematic representation of an embodiment of a vehicle 100 comprising the electric drive arrangement 1 according to or obtained by the above described embodiments or manufacturing methods.

[0076] The electric drive arrangement 1 is configured to propel the vehicle 100. The electric vehicle 100 comprises a wheel 101 coupled with the electric drive arrangement 1 in order to rotate the wheel 101. According to this embodiment, the electric vehicle 100 is a battery electric vehicle (BEV). Alternatively, the electric vehicle 100 can additionally comprise an internal combustion engine, wherein a hybrid electric vehicle is formed. Further, the electric vehicle 100 can comprise a fuel cell to supply the stator windings 5 of the stator 3 with electric power.

Claims

1. An electric drive arrangement (1) for a vehicle (100), the electric drive arrangement (1) comprising: - a stator (3) comprising stator windings (5) and a stator core (6) having a longitudinal axis (7) and opposite axial first and second face sides (8, 9), the stator windings (5) forming a first winding head (10) at the first face side (8) and a second winding head (11) at the second face side (9); and - a housing (12) having an interior (13) forming a stator accommodation space (14) and a radial stop (15) axially bounding the stator accommodation space (14); characterized in that - a spacer (26) is attached to the first face side (8) at a radial position further out than the first winding head (10) and abuts against the stop (15).

2. The electric drive arrangement according to claim 1, wherein - the spacer (26) is formed annularly around the longitudinal axis (7).

3. The electric drive arrangement according to claim 1 or 2, wherein - the housing (12) forms a coolant inlet for supplying coolant into the interior (13) of the housing (12) for cooling the stator (3).

4. The electric drive arrangement according to claim 3, further comprising - a first oil jet ring (28) attached to the first face side (8) of the stator core (6) at a radial position between the first winding head (10) and the spacer (26), such that the spacer (26) and the first oil jet ring (28) radially bound a first fluid chamber (29) fluidically connected to the inlet, the first oil jet ring (28) being configured to jet coolant from the first fluid chamber (29) towards the first winding head (10).

5. The electric drive arrangement according to claim 3 or 4, wherein - the housing (12) and the stator core (6) radially bound a cooling jacket (27) fluidically connected to the inlet and configured to guide coolant along an outer circumference of the stator core (6).

6. The electric drive arrangement according to claims 4 and 5, wherein - the spacer (26) comprises an opening (31) fluidically connecting the first fluid chamber (29) and the cooling jacket (27).

7. The electric drive arrangement according to any one of claims 4 to 6, wherein - the spacer (26) comprises two annular protrusions (32, 33) axially spaced apart and axially bounding the first fluid chamber (29).

8. The electric drive arrangement according to claim 7, wherein - the interior (13) of the housing (12) forms two annular protrusions (34, 35) corresponding to the protrusions (32, 33) of the first oil jet ring (28) and arranged at axial positions outside the stop (15) from the stator (3).

9. The electric drive arrangement according to any one of claims 3 to 8, further comprising - a second oil injection ring (36, 36') attached to the second face side (9) of the stator core (6) at a radially more outward position than the second winding head (11), such that the housing (12) and the second oil injection ring (36, 36') radially delimit a second fluid chamber (37) fluidically connected to the inlet, the second oil injection ring (36) being configured to inject coolant from the second fluid chamber (37) towards the second winding head (11).

10. The electric drive arrangement according to claim 9 when dependent on claim 5, wherein the cooling jacket (27) and the second fluid chamber (37) are fluidically connected.

11. The electric drive arrangement according to any one of the preceding claims, further comprising - an inverter (18) arranged in an inverter accommodation space (19) formed by the housing (12) on a side opposite to the stator accommodation space (14).

12. A method for manufacturing an electric drive arrangement (1) of a vehicle (100), the method comprising the steps of - providing a stator (3) comprising a stator winding (5) and a stator core (6) having a longitudinal axis (7) and opposite axial first (8) and second (9) face sides, the stator winding (5) forming a first winding head (10) at the first face side (8) and a second winding head (11) at the second face side (9); - providing a housing (12) having an interior (13) forming a stator accommodation space (14) and a radial stop (15) axially delimiting the stator accommodation space (14); - evaluating whether an axial length (LI, L2, L3, L4, L5) of the stator core (6) lies within at least one of at least two predetermined ranges (Rl, R2); - attaching a spacer (26) to the first face side (8) at a radially more outward position than the first winding head (10) if the axial length lies within at least one of the at least two ranges (Rl, R2); and - arranging the stator (3) into the stator accommodation space (14) such that the spacer (26) abuts against the stop (15) if the axial length (LI, L2) lies within at least one (Rl) of the at least two ranges, otherwise such that the first face side (8) abuts against the stop (15).

13. The method according to claim 12, further comprising the step of - evaluating in which one of a plurality of predefined sub-ranges (SRl, SR2, SR3) of a respective one of the ranges (Rl, R2) the length (LI, L2, L3, L4, L5) of the stator core (6) lies. ​ - attaching a second oil injection ring (36, 36', 36") to the second face side (9) of the stator core (6) at a radial position further outwards than the second winding head (11), wherein, if the axial length (LI, L3) lies within a first sub-range (SR1), a first type of second oil ring (36) having a first oil ring length is used, and if the axial length lies within a second sub-range (SR2), a second type of second oil ring (36') having a second oil ring length smaller than the first oil ring length is used.

14. The method of claim 13, wherein in the step of attaching the second oil injection ring (36, 36', 36"), if the axial length (LI) lies within a third sub-range (SR3), a third type of second oil injection ring (36") having a third oil ring length smaller than the second oil ring length is used.

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