Rotor arrangement for an electrical machine

Abstract

The invention relates to a rotor arrangement (2) for an electrical machine (1), comprising a first rotor segment (2A), a second rotor segment (2B) and a third rotor segment (2C), each with a plurality of laminations stacked to form a laminated core, wherein the second rotor segment (2B) is divided into a first sub-segment (2BA) and a second sub-segment (2BB), wherein each rotor segment (2A, 2B, 2C) has receiving pockets (3, 4) in its interior, which are designed such that permanent magnets (5) are received, and flux barriers (6, 7) are formed at ends of the respective permanent magnet (5) that are tangential to the rotor segment (2A, 2B, 2C), wherein the flux barriers (6, 7) are designed to receive a liquid cooling medium and to guide it in the axial direction of the rotor segment (2A, 2B, 2C), wherein axially between the two sub-segments (2BA, 2BB) an inlet disc (8) is arranged, which is designed and arranged toto receive a liquid cooling medium supplied to the rotor assembly (2) and to guide it radially outward to the flow barriers (6, 7), from where the cooling medium is divided and guided into the first sub-segment (2BA) and the second sub-segment (2BB). Furthermore, the invention relates to an electric machine (1) for driving a motor vehicle, comprising such a rotor assembly (2).

Description

[0001] The invention relates to a rotor arrangement for an electric machine and to an electric machine with such a rotor arrangement, wherein the electric machine is designed to drive a motor vehicle.

[0002] For an electric motor to operate at high power levels in a motor vehicle, effective cooling of the electric motor is necessary. The waste heat generated by the electric motor at high power levels can limit performance in certain applications, such as electrically driven axles. Critical factors include not only the temperature in the winding heads of the electric motor's stator, but also the temperature of the rotor. As soon as the electric motor exceeds a certain temperature limit, a control system typically reduces performance.

[0003] Rotors of electrical machines are usually designed as laminated cores. The laminated core has the function of conducting the magnetic flux, while also ensuring the mechanical cohesion of the rotor. In particular, it must absorb the centrifugal forces of each sub-section of the rotor. The laminated core has cutouts that serve either as pockets for permanent magnets or as a flux barrier. To prevent the laminated core from falling apart, the resulting laminated core geometry must form a continuous surface. When designing the laminated core contour, there is a conflict of objectives between the magnetic and mechanical functions in certain areas if low magnetic conductivity is required while simultaneously being subject to high mechanical stress. These areas are generally designed as thin webs.The width of these webs is designed to be as small as possible due to the requirement for low magnetic conductivity. On the other hand, the width must be chosen large enough to absorb the mechanical forces that occur. The remaining width leads to an undesirable magnetic flux through this web at this point.

[0004] For example, in permanent-magnet synchronous machines, flux barriers are used to prevent magnetic short circuits within the rotor. This ensures that the majority of the permanent magnet flux contributes to torque generation. One possible approach is to design the flux barriers as recesses in the rotor lamination, adjacent to the magnets. These recesses can be filled with air in the simplest form, or in other words, free of any filler material. It is also known to fill the recesses with plastic.

[0005] The object of the present invention is to propose a rotor assembly for an electric machine and an electric machine with improved cooling efficiency. This object is achieved by the subject matter of patent claims 1 and 10. Preferred embodiments are the subject matter of the dependent claims.

[0006] A rotor arrangement according to the invention for an electrical machine comprises a first rotor segment, a second rotor segment, and a third rotor segment, each with a plurality of laminations stacked to form a laminated core, wherein the second rotor segment is divided into a first sub-segment and a second sub-segment, wherein each rotor segment has receiving pockets in its interior which are designed to receive permanent magnets, and flux barriers are formed at ends of the respective permanent magnets which are tangential to the rotor segment, wherein the flux barriers are designed to receive a liquid cooling medium and to guide it in the axial direction of the rotor segment, wherein an inlet disk is arranged axially between the two sub-segments, which inlet disk is designed and arranged to receive a liquid cooling medium supplied to the rotor arrangement and to guide it radially outwards to the flux barriers,From there, the cooling medium is divided and directed into the first sub-segment and the second sub-segment. In other words, at least one inlet channel for supplying the liquid cooling medium is arranged radially within the flow barriers, with the inlet disc, i.e., means for distributing the cooling medium to the flow barriers, being designed.

[0007] The flux barriers are recesses in the sheet metal that are arranged laterally of the permanent magnets with respect to a rotational axis or the axial direction of the rotor assembly. In this case, the flux barriers are designed as cooling channels to achieve a cooling effect on the temperature-sensitive permanent magnets directly at the permanent magnets during operation. The liquid cooling medium is guided axially through the receiving pockets, in particular the flux barriers around the permanent magnets. This enables direct cooling of the permanent magnets in the receiving pockets or in the flux barrier.

[0008] In the context of this invention, "axial guidance of the cooling medium" means that the liquid cooling medium is guided or directed from one axial end of the rotor segment or sub-segment to the opposite end of the same rotor segment or sub-segment, essentially parallel to the rotational axis of the rotor assembly. Oil, for example, is a suitable liquid cooling medium.

[0009] By improving the cooling effect, heavy rare earth elements (HREEs) in particular can be reduced in the composition of permanent magnets, resulting in advantages in terms of manufacturing costs and sustainability. Alternatively, higher continuous performance of the electric machine can be achieved using the identical, already known magnet material. In particular, comparable performance of the electric machine can be achieved with a lower magnet quality.

[0010] The laminations of the laminated cores are arranged in an axial direction relative to a rotational axis of the rotor assembly to form the respective laminated core. Each laminated core forms the rotor segment or a sub-segment of the rotor segment. Thus, the laminations of the respective laminated cores are arranged axially aligned with one another. Each lamination has recesses that are designed and arranged such that, when the laminations are stacked to form the laminated core of the rotor segment or sub-segment, they form the aforementioned receiving pockets.

[0011] The receiving pockets are designed to accommodate a first permanent magnet, whereby, during operation of the electric machine, the cooling medium flows spatially between the respective sheet and the permanent magnet accommodated in the receiving pocket. The space between the respective sheet and the permanent magnet accommodated in the receiving pocket is to be understood as a flux barrier. Each permanent magnet is preferably partially surrounded by the sheet material and partially by the liquid cooling medium.

[0012] The first sub-segment is arranged axially between the first rotor segment and the second sub-segment. The second sub-segment is arranged axially between the third rotor segment and the first sub-segment.

[0013] The rotor arrangement has at least one inlet channel which extends from one axial end of the rotor arrangement via the first rotor segment and the first sub-segment or via the second rotor segment and the second sub-segment to the inlet disc. It is also conceivable for inlets to extend from both axial ends of the rotor arrangement to the inlet disc. The rotor arrangement also has at least two outlet channels, with at least one of the outlet channels extending from the inlet disc in a first axial direction and at least one further outlet channel also extending from the inlet disc in a second axial direction oriented opposite to the first axial direction.This means that at least one first discharge channel extends from the inlet disc through the first sub-segment and the first rotor segment to the first axial end of the rotor arrangement and at least one second discharge channel extends from the inlet disc through the second sub-segment and the third rotor segment to the opposite second axial end of the rotor arrangement.

[0014] The drainage channels are formed by the flux barriers in the receiving pockets and are arranged radially outward relative to the at least one inlet channel, so that the cooling medium can be conveyed outward by the centrifugal forces acting during operation. In one design variant of the rotor arrangement, each permanent magnet has a recess or flux barrier on both sides relative to its axial direction, each of which guides the cooling medium in the form of a drainage channel. Thus, two drainage channels are provided on each permanent magnet to cool the permanent magnet.

[0015] The inlet disc is preferably an annular disc arranged between the sub-segments and serving as a deflection element, whereby the cooling medium is deflected and guided from the at least one inlet channel into the flow barriers. The inlet disc is preferably arranged centrally in the second rotor segment, so that the sub-segments have essentially the same axial length. Likewise, the first and third rotor segments can be identical or mirror-inverted. The inlet disc can be made of aluminum or steel. It can be advantageous to use steel or other materials with low electrical conductivity. The inlet disc preferably has a thickness of less than 2 mm.

[0016] The inlet disk preferably has a plurality of substantially radially extending channels which are designed to receive the liquid cooling medium from at least one inlet channel and to guide it radially outwards, where the cooling medium is fed from the outlet channels formed by the flux barriers. The number, shape and orientation of the channels of the inlet disk depends on the number of receiving pockets or the number of permanent magnets to be cooled. For example, one channel can lead from the inlet channel to each flux barrier. Alternatively or additionally, a channel can be designed in a type of tree structure, with one channel or channel section being divided into at least two subsequent first-generation channels and, for example, each subsequent first-generation channel being divided into at least two subsequent second-generation channels, and so on.

[0017] The laminations of the rotor segments are preferably designed essentially identically, wherein the laminations of the second rotor segment are arranged tangentially offset relative to the laminations of the first and / or third rotor segment. The recesses of the laminations of a lamination stack are aligned with one another, so that the receiving pockets of the respective rotor or sub-segment are formed. Due to the tangential offset of adjacent rotor segments, the receiving pockets of the second rotor segment are not aligned with the receiving pockets of the first rotor segment and / or the receiving pockets of the third rotor segment. In one exemplary embodiment, one receiving pocket of each first rotor segment is arranged in alignment with a receiving pocket of the third rotor segment. The second rotor segment with its receiving pockets is arranged rotationally offset from the first and third rotor segments. This has advantages for the vibration properties of the electric machine during operation.It is understood that the receiving pockets of the sub-segments separated from each other by the inlet disc can be arranged in alignment with each other.

[0018] In this sense, a first deflection disk is arranged between the first sub-segment and the first rotor segment. This first deflection disk is configured and arranged to receive the liquid cooling medium guided in the flow barriers of the first sub-segment and to redirect it such that associated flow barriers of the first rotor segment receive the cooling medium and forward it axially. The first deflection disk is preferably an annular disk arranged between the first sub-segment and the first annular segment and serves as a deflection element. The first deflection disk preferably has a thickness of less than 2 mm.

[0019] Preferably, a second deflection disk is arranged between the second sub-segment and the third rotor segment. This second deflection disk is configured and arranged to receive the liquid cooling medium guided in the flow barriers of the second sub-segment and to redirect it such that associated flow barriers of the third rotor segment receive the cooling medium and forward it axially. The second deflection disk is preferably an annular disk arranged between the second sub-segment and the third annular segment and serves as a deflection element. The second deflection disk preferably has a thickness of less than 2 mm.

[0020] The deflection pulleys can be made of aluminum or steel. It may be advantageous to use steel or other materials with low electrical conductivity. The first and second deflection pulleys can be identical or mirror-inverted.

[0021] The respective deflection disk between the first and second, or the second and third, rotor segments can have elongated holes that serve as deflection channels and facilitate the flow of cooling medium between the two adjacent, tangentially offset rotor segments. The elongated holes can be aligned in a tangential direction, depending on the tangential offset between the immediately adjacent rotor segments.

[0022] In this sense, the respective deflection disk has a plurality of channels, each having a radial section and / or a tangential section, for redirecting cooling medium from a flow barrier of the respective subsection to a flow barrier of the associated first or third rotor segment. Regarding the channels of the deflection disks, reference is made to the explanations regarding the channels of the inlet disk, which are analogously applicable. The explanations regarding the deflection disks also apply analogously to the inlet disk.

[0023] By appropriately adapting and optimizing the cooling medium flow path, pressure losses and drag losses of the rotor arrangement can be further minimized.

[0024] The rotor assembly further comprises a first balancing disk and a second balancing disk, with the rotor segments being arranged axially between the two balancing disks. The balancing disks are designed to eliminate imbalances in a rotatable component, for example a rotor assembly of the electric machine. The rotor assembly is balanced using the balancing disks. Balancing can be achieved, for example, by specifically removing material along the circumference of the respective balancing disk, which is referred to as negative balancing. In this case, it is advantageous to form the balancing disks from metal, for example aluminum or steel, with balancing being achieved by mechanically removing material. Positive balancing refers to the application of additional weight to the balancing disk at a corresponding point along the circumference.Negative balancing, for example by drilling, grinding, milling or the like, is advantageous for the rotor arrangement proposed here.

[0025] Preferably, the first or second balancing disc has at least one inlet channel configured to provide liquid cooling medium to supply the at least one inlet channel of the rotor assembly. The liquid cooling medium is conveyed into the rotor assembly via the respective inlet channel. The at least one inlet channel is fluidly connected upstream to the first or second balancing disc, depending on where the inlet channel is provided, and downstream to the inlet disc. The inlet channel can be fluidly connected to a conveying device, for example a pump, which provides the liquid cooling medium and conveys it into the rotor assembly.

[0026] Preferably, both the first and second balancing discs have at least one outlet channel, each of which is configured to receive and discharge the liquid cooling medium from at least one outlet channel of the rotor assembly. The at least one outlet channel is fluidly connected upstream to the inlet disc and downstream to the first or second balancing disc or the at least one outlet channel of the respective balancing disc.

[0027] The cooling medium exiting through the outlet channels can be collected in a sump, reservoir, storage device, or the like located outside the rotor assembly. The cooling medium can, for example, be filtered and recirculated to the circuit or conveying device.

[0028] The invention further relates to an electric machine for driving a motor vehicle, comprising a stator and a rotor assembly rotatably mounted within the stator, as described above, wherein an air gap is arranged between the stator and the rotor assembly. The electric machine is used either alone or in combination with another electric machine or an internal combustion engine to drive the motor vehicle. For example, the electric machine is configured to drive one or more axles of the motor vehicle. The electric machine is, in particular, a permanent-magnet synchronous machine.

[0029] The electric machine comprises the rotating rotor assembly, hereinafter also referred to as the rotor, and a housing-fixed stator and can be operated as a motor or as a generator. In addition to the rotor and sub-segments and the optional balancing disks, the rotor assembly can also have a rotor shaft that is non-rotatably connected to the rotor or sub-segments. When the electric machine is operated as a motor, a voltage, in particular a time-variable voltage, can be applied to the stator and the windings therein in order to generate a spatially and temporally variable magnetic field that acts in the rotor to generate a torque and thus produce a rotary motion.When the electric machine is operated as a generator, electrical energy can be generated, for example, by inducing a varying magnetic field, for example by rotation of the rotor, into a looped or wound conductor of the stator to induce a voltage in the conductor.

[0030] In the following, a preferred embodiment of the invention is explained in more detail with reference to the drawings, in which like elements are provided with the same reference numerals. Fig. 1 is a schematic longitudinal section of an only partially shown electrical machine according to the invention, Fig. 2 a schematic perspective view of the rotor arrangement according to the invention according to Fig. 1, Fig. 3 a schematic partial cross-sectional view of a first partial segment of a second rotor segment of the rotor arrangement according to the invention according to Fig. 1 and Fig. 2 with an indicated inlet disc, Fig. 4 a schematic perspective view of the Fig. 3 indicated inlet disc, Fig. 5 a schematic partial cross-sectional view of a first rotor segment of the rotor arrangement according to the invention according to Fig. 1 to Fig. 3 with an indicated first deflection pulley, Fig. 6 a schematic perspective view of the Fig. 5 indicated first deflection pulley, and Fig. 7 a detailed perspective view of the rotor arrangement according to the invention according to Fig. 2 to illustrate the design of a first balancing disc.

[0031] According to Fig. 1 in conjunction with Fig. 2, an only partially illustrated electrical machine 1 according to the invention comprises a housing-fixed stator 22 and a rotatable rotor arrangement 2, wherein an air gap 23 is arranged radially between the stator 22 and the rotor arrangement 2.

[0032] The rotor assembly 2 comprises a rotor shaft 24 and three rotor segments 2A, 2B, 2C arranged thereon in a rotationally fixed manner, each comprising a plurality of laminations stacked to form a laminated core. The second rotor segment 2B, arranged between the first and second rotor segments 2A, 2C, is in turn divided into two sub-segments 2BA, 2BB, which have approximately the same spatial dimensions, in particular the same axial length. The rotor assembly 2 further comprises a first balancing disk 15 and a second balancing disk 16, wherein the rotor segments 2A, 2B, 2C are arranged axially between the two balancing disks 15, 16.

[0033] An inlet disk 8 is arranged axially between the two sub-segments 2BA, 2BB. A first deflection disk 11 is arranged axially between the first rotor segment 2A and the first sub-segment 2BA. A second deflection disk 12 is also arranged axially between the third rotor segment 2C and the second sub-segment 2BB. The inlet disk 8 and the deflection disks 11, 12 are designed to deflect or redirect a liquid cooling medium, referred to below as oil, conveyed into the rotor assembly 2. This is described in more detail below.

[0034] According to Fig. 2, the rotor arrangement 2 is formed in the axial direction by the first balancing disc 15, the first rotor segment 2A, the first deflection disc 11, the first sub-segment 2BA of the second rotor segment 2B, the inlet disc 8, the second sub-segment 2BB of the second rotor segment 2B, the second deflection disc 12, the third rotor segment 3C and the second balancing disc 16.

[0035] Fig. 3 shows a single sheet 25 or a sheet lamination of the first sub-segment 2BA in partial cross-section. In Fig. 3 also shows the inlet disk 8 or the channels 9 of the inlet disk 8, which in this illustration is located behind the sheet 25. The sheet 25 has a plurality of rotor poles, each rotor pole having a pole center axis 26 and an arrangement of permanent magnets 5 arranged in receiving pockets 3, 4, namely two radially inner larger permanent magnets 5 in each first receiving pocket 3 and two radially outer smaller permanent magnets 5 in each second receiving pocket 3.

[0036] With respect to an axial direction, which in the illustration Fig. 3 is directed into the plane, the larger first receiving pockets 3 have first flux barriers 6 to the left and right of the permanent magnets 5 received therein, and the smaller second receiving pockets 4 have second flux barriers 7 to the left and right of the permanent magnets 5 received therein. The flux barriers 6, 7 are designed as recesses in the sheet metal 25 at ends of the respective permanent magnet 5 that are tangential to the essentially circular sheet metal 25. The oil can be guided in the axial direction of the rotor arrangement 2 in the flux barriers 6, 7 or the recesses to the side of the permanent magnets 5.

[0037] It is understood that several such rotor poles are arranged over the circumference of the sheet 25 or the rotor segment 2A, 2B, 2C, which are essentially identical in design, cf. Fig. 4. The illustrations chosen here serve only to provide a simple description of the structure of the rotor assembly 2, so that the illustration of the entire rotor assembly 2 ( Fig. 1, Fig. 2 and Fig. 7) or the entire sheet 25 ( Fig. 3 and Fig. 5) is waived.

[0038] The laminations of all rotor segments 2A, 2B, 2C are essentially identical, with the laminations of the second rotor segment 2B being arranged tangentially offset relative to the laminations of the first and third rotor segments 2A, 2C. Thus, the laminated core of the second rotor segment 2B or of the sub-segments 2BA, 2BB formed from the laminations is arranged rotated relative to the laminations of the first and third rotor segments 2A, 2C about the rotation axis of the rotor assembly 2.

[0039] In Fig. 3 also shows an inlet channel 10 of the rotor assembly 2 by way of example, through which the oil is supplied to the system and is guided to the inlet disk 8 in the center of the rotor assembly 2. This is simplified by the first arrow P1 in Fig. 1. The inlet channel 10 can be supplied with oil upstream by a pump (not shown here). Whenever reference is made to an inlet channel 10, this applies to all other inlet channels 10 of the rotor assembly 2, which, for example, Fig. 4. Accordingly, one inlet channel 10 is provided for each associated rotor pole, with the inlet channels 10 being evenly distributed over the circumference.

[0040] Fig. 4 in conjunction with Fig. 3 shows the inlet disc 8 with channels 9 extending from the six inlet channels 10, essentially radially outwardly directed, wherein the oil from the inlet channels 10 is guided radially outwardly via the channels 9 by the centrifugal forces acting during operation and is fed to the flow barriers 6, 7. This is simplified by the second arrow P2 in Fig. 1. In addition, the channels 9 are initially led to the radially inner first flow barriers 6 and from there to the radially outer second flow barriers 7.

[0041] When the oil reaches the flow barriers 6, 7, the oil is simplified according to the third and fourth arrows P3, P4 to Fig. 1 is conveyed over the aligned flow barriers 6, 7 of the first and second sub-segments 2BA, 2BB to the left and right, respectively, i.e. in opposite axial directions, until the oil reaches the first and second deflection pulleys 11, 12, respectively.

[0042] The flux barriers 6, 7 within the first sub-segment 2BA are to be understood as first drainage channels 18, while the flux barriers 6, 7 within the second sub-segment 2BB are to be understood as second drainage channels 19. The oil in the inlet channel 10 is thus deflected by the inlet disc 8 and discharged via the drainage channels 18, 19 in opposite axial directions, whereby the oil flowing in the drainage channels 18, 19 cools the permanent magnets 5.

[0043] Via the flow barriers 6, 7 of the first sub-segment 2BA, oil is guided along the first discharge channels 18 to the first deflection disk 11 between the first sub-segment 2BA and the first rotor segment 2A (third arrow P3 in Fig. 1). At the same time, oil is guided via the flow barriers 6, 7 of the second sub-segment 2BB along the second discharge channels 19 to the second deflection disk 12 between the second sub-segment 2BB and the third rotor segment 2C (fourth arrow P3 in Fig. 1).

[0044] The first deflection disk 11 is designed and arranged to receive the oil guided in the flow barriers 6, 7 of the first sub-segment 2BA and to redirect it in such a way that the flow barriers 6, 7 of the first rotor segment 2A, which is tangentially offset to the first sub-segment 2BA, receive the oil and, according to a fifth arrow P5, it is passed on in the direction of the first balancing disk 15.

[0045] The second deflection disk 12 is designed and arranged to receive the oil guided in the flow barriers 6, 7 of the second sub-segment 2BB and to redirect it in such a way that the flow barriers 6, 7 of the third rotor segment 2C, which is tangentially offset to the second sub-segment 2BB, receive the oil and are passed on in the direction of the second balancing disk 16 according to a sixth arrow P6.

[0046] Fig. 5 also shows a sheet 25 or a sheet lamination of the first sub-segment 2BA in partial cross-section, but in comparison to Fig. 3 opposite viewing direction, namely onto the first deflection disk 11, in particular channels 13, 14 of the first deflection disk 11. It should be clarified that the channels 13, 14 on the first deflection disk 11 are shaped and aligned in such a way that the oil can be deflected from the flow barriers 6, 7 of the first sub-segment 2BA into the flow barriers 6, 7 of the first rotor segment 2A without loss. The channels which guide the oil from the flow barriers 6 of the radially inner receiving pockets 3 in the first sub-segment 2BA into the flow barriers 6 of the inner receiving pockets 3 in the first ring segment 2A are provided with the reference numeral 13. The channels which guide the oil from the flow barriers 7 of the radially outer receiving pockets 4 in the first sub-segment 2BA into the flow barriers 6 of the outer receiving pockets 4 in the first ring segment 2A are provided with the reference numeral 14.

[0047] Fig. Figure 6 shows the first deflection disk 11 as an example. The channels 13, 14 can be formed in the form of elongated holes in a substantially tangential and / or radial direction. Thus, the channels 13, 14 can each have a radial section and / or a tangential section. Furthermore, it is shown that openings are formed radially inside the annular disk as part of the inlet channels 10. The channels 13, 14 are shaped depending on the configuration of the aforementioned rotor poles.

[0048] The second deflection pulley 12 is designed as a mirror image of the first deflection pulley 11, so that the explanations for the first deflection pulley 11 apply analogously to the second deflection pulley 12. Therefore, with regard to the second deflection pulley 12, reference is made to the previous explanations for the first deflection pulley 11, and a separate representation in the figures is omitted.

[0049] Fig. 7 shows an axial end of the rotor assembly 2, namely the end of the rotor assembly 2 at which the first balancing disc 15 is arranged. Fig. 7 illustrates that the rotor assembly 2 is hollow inside to guide the rotor shaft 24 Fig. 1. In the area of ​​the inner circumference or radially inside, the first balancing disk 15 has six inlet channels 17, which are designed and arranged in alignment with the previously described inlet channels 10. Further outwards, there are also six through holes 27, which are each intended to receive a tie rod (not shown here), with which the rotor assembly 2 can be clamped in order to realize a uniform force distribution within the rotor. The through holes 27 extend axially through the entire rotor assembly 2. Accordingly, through holes 27 are also provided in Fig. 2 and correspondingly in the inlet disc 8 according to Fig. 4, in the partial sections after Fig. 3 and Fig. 5 and in the first deflection pulley 11 after Fig. 6 shown.

[0050] Radially outward, in the area of ​​the outer circumference of the rotor assembly 2, the first balancing disk 15 has a plurality of outlet channels 20, 21, whereby the number of outlet channels 20, 21 corresponds to the number of drain channels 18, 19 within the first rotor segment 2A. Thus, each outlet channel 20, 21 is aligned with a corresponding drain channel 18, 19. The outlet channels 20, 21 receive the oil from the drain channels 18, 19 and drain it away. The outlet channels 20, 21 can be fluidically connected to a sump or storage device (not shown here).

[0051] The outlet channels, which receive the oil from the flow barriers 6 of the radially inner receiving pockets 3 in the first ring segment 2A, are provided with the reference numeral 20. The outlet channels, which receive the oil from the flow barriers 7 of the radially outer receiving pockets 4 in the first ring segment 2A, are provided with the reference numeral 21.

[0052] The second balancing disc 16 is essentially a mirror image of the first balancing disc 15, so that the statements regarding the first balancing disc 15 apply analogously to the second balancing disc 16, with the exception that the second balancing disc 16 does not have any inlet channels 17, because the rotor assembly 2 is supplied with oil from only one axial side to improve the line design and arrangement. The number of outlet channels 20, 21 on the second balancing disc 16 is equal to the number of outlet channels 18, 19 within the third rotor segment 2C. Furthermore, with regard to the second balancing disc 16, reference is made to the previous statements regarding the first balancing disc 15.

[0053] It is conceivable to provide the aforementioned inlet channels 17 only on the second balancing disk 16. Furthermore, it is conceivable for both the first and second balancing disks 15, 16 to have at least one inlet channel 17, each of which is configured to provide liquid cooling medium for supplying the at least one inlet channel 10, in particular an access channel 10 associated with the inlet channel 17. It is of course also possible to design one or both balancing disks 15, 16 such that an inlet channel 17 is associated with multiple inlet channels 10 and / or that an outlet channel 20, 21 is associated with multiple outlet channels 18, 19, or vice versa. Reference symbol 1 Electric machine 2 Rotor arrangement 2A First rotor segment 2B Second rotor segment 2BA First sub-segment of the second rotor segment 2BB Second sub-segment of the second rotor segment 2C Third rotor segment 3 Recording pocket 4 Recording pocket 5 Permanent magnet 6 River barrier 7 River barrier 8 Inlet disc 9 Channel of the inlet disc 10 Inlet channel of the rotor assembly 11 First deflection pulley 12 Second deflection pulley 13 Channel of the first deflection pulley 14 Channel of the second deflection pulley 15 First balancing disc 16 Second balancing disc 17 input channel 18 First drainage channel 19 Second drainage channel 20 First output channel 21 Second output channel 22 Stator 23 Air gap 24 Rotor shaft 25 sheets 27 Through hole P1 First Arrow P2 Second Arrow P3 Third Arrow P4 Fourth Arrow P5 Fifth Arrow P6 Sixth Arrow

Claims

[1] Rotor arrangement (2) for an electrical machine (1), comprising a first rotor segment (2A), a second rotor segment (2B) and a third rotor segment (2C), each with a plurality of laminations stacked to form a laminated core, wherein the second rotor segment (2B) is divided into a first sub-segment (2BA) and a second sub-segment (2BB), wherein each rotor segment (2A, 2B, 2C) has receiving pockets (3, 4) in the interior, which are designed such that permanent magnets (5) are received, and flux barriers (6, 7) are formed at ends of the respective permanent magnet (5) that are tangential to the rotor segment (2A, 2B, 2C), wherein the flux barriers (6, 7) are designed to receive a liquid cooling medium and to guide it in the axial direction of the rotor segment (2A, 2B, 2C), wherein axially between the two sub-segments (2BA, 2BB) a Inlet disc (8) is arranged, which is designed and arranged toto receive a liquid cooling medium supplied to the rotor arrangement (2) and to guide it radially outwards to the flow barriers (6, 7), from where the cooling medium is divided and guided into the first sub-segment (2BA) and the second sub-segment (2BB). [2] Rotor arrangement (2) according to claim 1, wherein the inlet disc (8) has a plurality of substantially radially extending channels (9) which are adapted to receive the liquid cooling medium from at least one inlet channel (10) and to guide it radially outwards, where the cooling medium is supplied from the flow barriers (6, 7) formed outlet channels (18, 19). [3] Rotor arrangement (2) according to claim 1 or 2, wherein the laminations of the rotor segments (2A, 2B, 2C) are substantially identical, wherein the laminations of the second rotor segment (2B) are arranged tangentially offset relative to the laminations of the first and / or third rotor segment (2A, 2C). [4] Rotor arrangement (2) according to claim 3, wherein a first deflection disk (11) is arranged between the first sub-segment (2BA) and the first rotor segment (2A), which first deflection disk is designed and arranged to receive the cooling medium guided in the flux barriers (6, 7) of the first sub-segment (2BA) and to redirect it in such a way that flux barriers (6, 7) of the first rotor segment (2A) receive the cooling medium and forward it axially. [5] Rotor arrangement (2) according to claim 3 or 4, wherein a second deflection disk (12) is arranged between the second sub-segment (2BB) and the third rotor segment (2C), which second deflection disk is designed and arranged to receive the cooling medium guided in the flux barriers (6, 7) of the second sub-segment (2BB) and to redirect it in such a way that flux barriers (6, 7) of the third rotor segment (2C) receive the cooling medium and forward it axially. [6] Rotor arrangement (2) according to claim 5, wherein the respective deflection disk (11, 12) has a plurality of channels (13, 14), each having a radial section and / or a tangential section, in order to divert cooling medium from a flow barrier (6, 7) of the respective sub-section (2BA, 2BB) to a flow barrier (6, 7) of the associated first or third rotor segment (2A, 2C). [7] Rotor arrangement (2) according to one of the preceding claims, further comprising a first balancing disc (15) and a second balancing disc (16), wherein the rotor segments (2A, 2B, 2C) are arranged axially between the two balancing discs (15, 16). [8] Rotor arrangement (2) according to claim 7, wherein the first or second balancing disc (15, 16) has at least one inlet channel (17) which is designed to provide liquid cooling medium for supplying the at least one inlet channel (10) of the rotor arrangement (2). [9] Rotor arrangement (2) according to claim 7 or 8, wherein both the first and the second balancing disc (15, 16) have at least one outlet channel (20, 21) which is each adapted to receive and discharge liquid cooling medium from at least one outlet channel (18, 19) of the rotor arrangement (2). [10] Electric machine (1) for driving a motor vehicle, comprising a stator (22) and a rotor arrangement (2) rotatably mounted within the stator (22) according to one of the preceding claims, wherein an air gap (23) is arranged between the stator (22) and the rotor arrangement (2).

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