Rotor of an electric machine

Abstract

The invention relates to a rotor of an electric machine (2), having a rotor shaft (4), which can be rotated about a rotor axis (3), and a laminated rotor core (5), which is mounted on the rotor shaft (4) and in which a plurality of rotor cooling channels (6) are provided that extend in the axial direction with respect to the rotor axis (3) and can be supplied with cooling fluid, in particular oil, via a hollow rotor shaft (4) in order to cool the rotor (1), wherein the hollow rotor shaft (4) is fluidically connected to the rotor cooling channels (6) via at least one supply path (7) which runs in particular through the laminated rotor core (5) in the radial direction; each supply path (7) is formed in a central core portion (5m) between two outer core portions (5a) of the laminated rotor core (5); and at least one retaining wall (20) for retaining the cooling fluid in the rotor cooling channel (6) is formed in each rotor cooling channel (6) downstream of a channel inlet (26) leading into the rotor cooling channel (6), the retaining wall extending towards the two channel ends of the rotor cooling channel (6).

Description

[0001] R. 417371 -1

[0002] 1

[0003] Description

[0004] title

[0005] Rotor of an electric machine

[0006] State of the art

[0007] The invention relates to a rotor of an electric machine according to the preamble of the main claim.

[0008] A rotor of an electric machine is already known from US2019267859 A1, comprising a rotor shaft rotatable about a rotor axis, a rotor lamination stack arranged on the rotor shaft, and several rotor cooling channels extending axially with respect to the rotor axis. These cooling channels can be supplied with cooling fluid, in particular oil, via a hollow rotor shaft. The hollow rotor shaft is fluidically connected to the rotor cooling channels via at least one supply path, which extends radially through the rotor lamination stack. The respective supply path is formed in a central stack section between two outer stack sections of the rotor lamination stack.At both end faces of the rotor lamination stack, an end disk arrangement is provided, which includes at least one outlet end disk with fluid outlets for the flow of cooling fluid from the rotor cooling channels, in particular for winding head cooling of a stator winding.

[0009] Advantages of the invention

[0010] In contrast, the rotor of an electric machine according to the invention, with the characterizing features of the main claim, has the advantage that the cooling of the rotor is improved by establishing a stable cooling flow with two opposing partial flows in the respective rotor cooling channel. The volume flow entering the respective rotor cooling channel is thus reliably and stably divided during operation into two opposing partial flows, so that the two sections of the rotor lamination stack cooled by the two partial flows are cooled uniformly. In particular, it is avoided that the volume flow entering the respective rotor cooling channel flows only or predominantly in only one of the two axial directions of the respective rotor cooling channel. R. 417371-1

[0011] 2

[0012] This is achieved according to the invention by forming at least one stagnation wall in the rotor cooling channel downstream of a channel inlet to the two channel ends of the rotor cooling channel to cause the cooling fluid to accumulate in the rotor cooling channel.

[0013] The measures listed in the dependent claims enable advantageous further developments and improvements of the rotor of an electric machine specified in the main claim.

[0014] It is highly advantageous if the respective baffle wall in the respective rotor cooling channel projects radially inwards in the radial direction relative to the rotor axis compared to a radially outer, and in particular radially outermost, channel wall of the associated rotor cooling channel. In this way, a build-up of the cooling fluid in the rotor cooling channel can be achieved.

[0015] According to advantageous embodiments, the respective baffle wall in the respective rotor cooling channel can be formed, for example, at an end lamella of the rotor lamination stack, at a balancing disc or at a sublamella below an end lamella.

[0016] Furthermore, it is advantageous if an end disk arrangement is provided at each of the two end faces of the rotor lamination stack, comprising at least one outlet end disk with fluid outlets for the flow of cooling fluid from the rotor cooling channels, particularly for winding head cooling of a stator winding. At least one of the fluid outlets of the outlet end disk of the respective end disk arrangement is offset radially inward relative to the associated rotor cooling channel with respect to the rotor axis such that a baffle wall is formed at the outlet end disk at the end of the associated rotor cooling channel for the accumulation of cooling fluid in the associated rotor cooling channel. The multiple baffles of the respective outlet end disk are, in particular, formed integrally with the outlet end disk. In particular, all fluid outlets of the outlet end disk of the respective end disk arrangement are offset radially inward according to the invention.The radial offset of the fluid outlets relative to the rotor cooling channels can be formed by offsetting the centroid of the outlet cross-section of each fluid outlet radially inwards relative to the centroid of the channel cross-section of the respective rotor cooling channel. R. 417371 -1.

[0017] 3

[0018] According to an advantageous embodiment, the baffle wall at the end of the associated rotor cooling channel projects radially inwards in the radial direction relative to the rotor axis, relative to a radially outer, and in particular the outermost, channel wall of the associated rotor cooling channel, and extends to a radially outer edge of the respective fluid outlet of the outlet end disk. In this way, the respective outlet end disk can form the baffle walls for accumulating the cooling fluid in the rotor cooling channels. This allows a stable cooling flow with two opposing and, in particular, equally sized partial flows to be established in the respective rotor cooling channel.

[0019] It is also advantageous if the fluid outlets of the outlet end disk of the respective end disk arrangement each have an outlet cross-section that is offset radially inwards relative to the channel cross-section of the associated rotor cooling channel and, in particular, is smaller than the channel cross-section of the associated rotor cooling channel. In this way, the backwater walls in the rotor cooling channels are formed. A reduced outlet cross-section of the fluid outlets allows for backwater of the cooling fluid by means of a throttling at the end of the rotor cooling channels.

[0020] According to an advantageous first embodiment, the outlet end disk of the respective end disk arrangement is an end lamella of the rotor lamination stack, wherein the respective end disk arrangement additionally comprises, in particular, a balancing disk which has fluid passages for guiding the cooling fluid from the fluid outlets. In this way, the accumulation of the cooling fluid at one end of the respective rotor cooling channel can be created with an end lamella that is a special lamella of the rotor lamination stack and is comparatively cost-effective.

[0021] In one variant of the first embodiment, the outlet end disk of the respective end disk assembly is a balancing disk located on an end face of the rotor lamination stack. This reduces the manufacturing costs of the rotor, as the balancing disk forms the baffle walls, thus eliminating the need for the special lamellae in the rotor lamination stack of the first embodiment. R. 417371-1

[0022] 4

[0023] It is further advantageous if at least one seal is provided between the outlet end disk of the respective end disk assembly, designed as a balancing disk, and the rotor lamination stack to prevent leakage from the rotor cooling channels into an annular gap formed between the outlet end disk and the rotor lamination stack. The seal can, for example, be integrally molded onto the balancing disk, e.g., by injection molding, or be provided as a separate part. By preventing leakage, a stable fluid film can be ensured in the rotor cooling channel during rotation, which is available for cooling both axial halves of the rotor.

[0024] It is particularly advantageous if, according to a second embodiment, the respective end disk arrangement additionally comprises at least one deflecting disk arranged between the outlet end disk and the rotor lamination stack, and in particular is a special lamella of the rotor lamination stack, and / or

[0025] Radially extending deflection recesses are formed, which each deflect the cooling fluid from the respective rotor cooling channel radially inwards to the associated fluid outlet.

[0026] In this way, radially inward-leading radial channels are formed in the respective deflection disc, connecting the respective rotor cooling channel with the associated fluid outlet of the respective outlet end disc. Furthermore, this method allows for a comparatively strong accumulation of cooling fluid in the rotor cooling channels.

[0027] It is highly advantageous if the rotor cooling channels have a partially annular, arc-shaped, kidney-shaped, T-shaped, or oblong cross-section and / or are arranged, particularly in the circumferential direction, between adjacent rotor poles. This improves rotor cooling.

[0028] It is also advantageous if several, in particular all, rotor cooling channels are interconnected via at least one annular distribution channel formed in the rotor, especially in one of the end disk arrangements and / or in the rotor lamination stack. This reduces rotor imbalance during start-up.

[0029] Furthermore, it is advantageous if the rotor lamination stack comprises a stack of lamellae, which are in particular bonded together. By bonding the R. 417371 -1

[0030] 5

[0031] A seal can be achieved between the fins against the cooling fluid.

[0032] Furthermore, it is advantageous if the rotor is enclosed by a rotor sleeve. This increases the rotor's speed stability. Additionally, the rotor sleeve can create a seal within the rotor against the cooling fluid, for example, if the balancing disc extends to the outer circumference of the rotor lamination stack and the rotor sleeve also encloses the balancing disc.

[0033] The invention further relates to an electric machine comprising a stator having a stator winding with winding heads and a rotor according to the invention.

[0034] drawing

[0035] Exemplary embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.

[0036] They show:

[0037] Fig. 1 shows a first embodiment of an end disk arrangement of a rotor of an electric machine according to the invention, Fig. 2A shows a partial view of the rotor according to Fig. 1 with a fluid outlet according to the invention from a rotor cooling channel,

[0038] Fig. 2B shows a variant of the first embodiment according to Fig. 2A,

[0039] Fig. 3A shows a lamellar outlet end disk of the end disk arrangement according to the invention as shown in Fig. 1.

[0040] Fig. 3B shows one of the lamellae Lc for forming the rotor lamination stack according to Fig. 1, Fig. 4 shows a second embodiment of an end disk arrangement according to the invention for a rotor of an electric machine.

[0041] Fig. 5 shows a partial view of the rotor according to Fig. 4.

[0042] Fig. 6A shows a lamellar outlet end disk of the end disk arrangement according to the invention as shown in Fig. 4.

[0043] Fig. 6B shows a lamellar deflecting disc of the end disc arrangement according to the invention as shown in Fig. 4, R. 417371 -1

[0044] 6

[0045] Fig. 6C shows one of the lamellae Lc for forming the rotor lamination stack according to Fig. 4 and Fig. 6D shows another special lamella for forming a distribution channel in the rotor lamination stack according to Fig. 4.

[0046] Description of the exemplary implementations

[0047] Fig. 1 shows in section a first embodiment of an end disk arrangement according to the invention for a rotor of an electric machine.

[0048] The rotor 1 of an electric machine 2 comprises a rotor shaft 4 rotatable about a rotor axis 3 and a rotor lamination stack 5 arranged on the rotor shaft 4, in which several rotor cooling channels 6 extending axially with respect to the rotor axis 3 are formed and which can be supplied with cooling fluid, in particular oil, via the hollow rotor shaft 4 for cooling the rotor 1. The rotor lamination stack 5 is formed by a stack of laminations L, which are firmly connected to one another, in particular by adhesive or molding compound, or joined together by interlocks. For the purposes of the application, laminations L are understood to be sheet metal laminations made of electrical steel.

[0049] The rotor 1, for example, is a rotor of a permanent magnet excited synchronous machine, which has a magnet arrangement 30 comprising at least one permanent magnet 31 per rotor pole.

[0050] The electric machine 2 comprises, in addition to the rotor 1, a stator 40 which has a stator winding 41 with winding ends 41h. In the radial direction with respect to the rotor axis 3, an air gap 45 is formed between the stator 40 and the rotor 1.

[0051] The rotor cooling channels 6 are formed by channel openings 8 in the fins L of the rotor lamination stack 5.

[0052] The hollow rotor shaft 4 is fluidically connected to the rotor cooling channels 6 via at least one supply path 7, which runs through the rotor lamination stack 5, particularly in the radial direction with respect to the rotor axis 3. The respective supply path 7 is formed in a central stack section 5m between two outer stack sections 5a of the rotor lamination stack 5. The respective supply path 7 is located in the middle stack section 5m between two outer stack sections 5a of the rotor lamination stack 5.

[0053] 7

[0054] Supply path 7 can be formed, for example, by overlapping path recesses 7s in adjacent lamellae L of the middle package section 5m.

[0055] In each of the rotor cooling channels 6, two cooling paths 9 extending in opposite axial directions are formed, leading from a channel inlet 26 into the respective rotor cooling channel 6. The channel inlets 26 into the rotor cooling channels 6 are located in the central package section 5m.

[0056] The outer package sections 5a of the rotor lamination package 5 are formed completely or at least predominantly by stacking identical lamellae Lc of the same lamella type.

[0057] At each of the two end faces of the rotor lamination stack 5, an end plate arrangement 10 can be provided, comprising at least one outlet end plate 11 with fluid outlets 12 for the flow of cooling fluid from the rotor cooling channels 6. The fluid outlets 12 can be provided, in particular, for winding head cooling of a stator winding of a stator of the electric machine 2.

[0058] The rotor 1 can be enclosed by a rotor sleeve (not shown) to increase its speed stability.

[0059] Fig. 2A shows a partial view of the rotor according to Fig. 1 with a fluid outlet according to the invention from a rotor cooling channel.

[0060] According to the invention, it is provided that in the respective rotor cooling channel 6, downstream of a channel inlet 26 into the rotor cooling channel 6, at least one damming wall 20 is formed to dam the cooling fluid in the rotor cooling channel 6 at each of the two channel ends.

[0061] The respective baffle wall 20 in the respective rotor cooling channel 6 projects radially inwards with respect to the rotor axis 3 opposite a radially outer, in particular radially outermost, channel wall 6a of the associated rotor cooling channel 6.

[0062] The respective baffle wall 20 in the respective rotor cooling channel 6 can be attached to an end lamella Le of the rotor lamination stack 5, to a balancing disc 14 or to an R. 417371 -1

[0063] 8

[0064] A sublamella is formed below an end lamella Le. The respective baffle wall 20 in the respective rotor cooling channel 6 can therefore be arranged in the axial direction between the respective channel inlet 26 and one of the channel ends of the respective rotor cooling channel 6, for example, at a channel end or in an end section of the respective rotor cooling channel 6.

[0065] At each of the two end faces of the rotor lamination stack 5, for example, an end disk arrangement 10 is provided, which includes at least one outlet end disk 11 with fluid outlets 12 for the flow of cooling fluid from the rotor cooling channels 6, in particular for winding head cooling of a stator winding. At least one of the fluid outlets 12 of the outlet end disk 11 of the respective end disk arrangement 10 is offset radially inwards relative to the associated rotor cooling channel 6 with respect to the rotor axis 3 such that the outlet end disk 11 forms a baffle 20 at the end of the associated rotor cooling channel 6 for accumulating the cooling fluid in the associated rotor cooling channel 6.

[0066] The damming wall 20, for example, projects radially inwards at the end of the associated rotor cooling channel 6 with respect to the rotor axis 3 relative to a radially outer, in particular radially outermost, channel wall 6a of the associated rotor cooling channel 6 and extends to a radially outer edge 12a of the respective fluid outlet 12 of the outlet end disk 11. In the respective rotor cooling channel 6, the cooling fluid accumulates between the channel wall 6a and the radially outer edge 12a as a liquid column 25.

[0067] The fluid outlets 12 of the outlet end disk 11 of the respective end disk arrangement 10 each have an outlet cross-section which is offset radially inwards compared to a channel cross-section of the associated rotor cooling channel 6 and is in particular smaller than the channel cross-section of the associated rotor cooling channel 6.

[0068] According to the first embodiment, the outlet end disk 11 of the respective end disk arrangement 10 is an end lamella Le of the rotor lamination stack 5. The end lamella Le is a special lamella that differs from the lamellae Lc of one of the outer stack sections 5a of the rotor lamination stack 5 at least in the fluid outlets 12, which are offset radially inwards and provided instead of the channel openings 8. The outlet end disk 11 has, for example, the same R. 417371 -1

[0069] 9

[0070] Outer diameter and / or inner diameter like the lamellae Lc. The outlet end disk 11 of the respective end disk arrangement 10 can be firmly connected to an adjacent lamella Lc of the rotor lamination stack 5, for example by bonding.

[0071] According to the first embodiment, the respective end disk arrangement 10 can additionally include a balancing disk 14, which in particular has fluid passages 15 for guiding the cooling fluid from the fluid outlets 12 and serves to balance the rotor. The balancing disk 14 can be bonded to the adjacent outlet end disk 11 by means of adhesive or molding compound.

[0072] The balancing disc 14 extends in a radial direction with respect to the rotor axis 3 beyond the respective rotor cooling channel 6.

[0073] Axial pressure forces from the cooling fluid present in the rotor cooling channels 6 can act on the outlet end disk 11 of the respective end disk arrangement 10 during rotation of the rotor 1. These axial pressure forces can be supported, for example, by the balancing disk 14.

[0074] Fig. 2B shows a variant of the first embodiment according to Fig. 2A.

[0075] According to the variant of the first embodiment, the outlet end disk 11 of the respective end disk arrangement 10 is the balancing disk 14, which is arranged on an end face of the rotor lamination stack 5, which has fluid outlets 15 offset radially inwards according to the invention and forms the baffle walls 20 according to the invention.

[0076] According to this variant, the end lamella Le of the rotor lamination stack 5 has, instead of the fluid outlets 12, which are radially offset inwards and, in particular, reduced in size compared to the cross-section of the rotor cooling channels 6, the channel openings 8 for forming the rotor cooling channels 6. The end lamella Le of the rotor lamination stack 5 can thus, for example, be a lamella Lc.

[0077] Between the outlet end disk 11 of the respective end disk arrangement 10, designed as a balancing disk 14, and the rotor lamination stack 5, at least one seal 16 can be installed to prevent leakage from the rotor cooling channels 6 into a R. 417371 -1

[0078] 10

[0079] The annular gap formed between the outlet end disk 11 and the rotor lamination stack 5 is provided. The seal 16 can, for example, be a flat gasket.

[0080] Fig. 3A shows a lamellar outlet end disk of the end disk arrangement according to Fig. 1 according to the invention.

[0081] The fluid outlets 12 of the outlet end disk 11 are, for example, designed in the shape of oblong holes.

[0082] Fig. 3B shows one of the lamellae Lc for forming the rotor lamination stack according to Fig. 1.

[0083] The channel openings 8 of the lamella Lc are, for example, elongated or slot-shaped and each has two outer opening sections 8a and a central opening section 8m arranged between the two outer opening sections 8a. The central opening section 8m has a radial opening height hm, which is greater than the radial opening height ha of the outer opening sections 8a.

[0084] The fluid outlet 12 of the outlet end disk 11, which is assigned to the rotor cooling channel 6, leads into the opening center section 8m of the channel opening 8 of the adjacent lamella Lc.

[0085] Fig. 4 shows a second embodiment of an end disk arrangement of a rotor of an electric machine according to the invention.

[0086] The second embodiment differs from the first embodiment only in that the respective end disk arrangement additionally includes at least one deflecting disk 13.

[0087] The deflecting disc 13 is arranged between the outlet end disc 11 and the rotor lamination stack 5 and is, for example, a special lamella of the rotor lamination stack 5. Radially extending deflecting recesses 17 are formed on the deflecting disc 13, each of which deflects the cooling fluid from the respective rotor cooling channel 6 radially inwards to the associated fluid outlet 12, which is offset radially inwards. R. 417371 -1

[0088] 11

[0089] The deflecting disc 13 of the respective end disc arrangement 10 can be firmly connected, for example by bonding, to the adjacent outlet end disc 11 and / or an adjacent lamella L of the rotor lamination stack 5.

[0090] Furthermore, the balancing disc 14 can be bonded to the adjacent outlet end disc 11 using adhesive or molding compound.

[0091] Fig. 5 shows a partial view of the rotor according to Fig. 4.

[0092] Fig. 6A shows a lamellar outlet end disk of the end disk arrangement according to Fig. 4 according to the invention.

[0093] The lamellar outlet end disk 11 has one fluid outlet 12 per rotor cooling channel 6.

[0094] Fig. 6B shows a lamellar deflecting disc of the end disc arrangement according to Fig. 4 according to the invention.

[0095] The lamellar deflecting disc 13 has a channel opening 8 for each rotor cooling channel 6 and a deflecting recess 17 extending radially inwards from the respective channel opening 8.

[0096] Fig. 6C shows one of the lamellae Lc for forming the rotor lamination stack according to Fig. 4.

[0097] The lamella Lc has a channel opening 8 per rotor cooling channel 6, which is designed, for example, as a slot or elongated hole and forms part of the rotor cooling channel 6.

[0098] Fig. 6D shows another special lamella for forming a distribution channel in the rotor lamination stack according to Fig. 4.

[0099] In rotor 1, several, in particular all, rotor cooling channels 6 can be flow-connected via at least one annular distributor channel formed in rotor 1, in particular in one of the end disk arrangements 10 and / or in the rotor lamination stack 5. R. 417371 -1

[0100] - 12 -

[0101] To form the distribution channel, the respective end disk arrangement 10 can, for example, additionally comprise at least one further special lamella Ls according to Fig. 6D. The further special lamella Ls according to Fig. 6D has several connecting openings 18 arranged along the circumferential direction for overlapping with the channel openings 8 of the deflecting disk 13 and thus for forming the distribution channel. The further special lamella Ls according to Fig. 6D can also have deflecting recesses 17 corresponding to the deflecting disk 13.

[0102] Alternatively, the distribution channel in the balancing disc 14 can be formed as a circumferential groove.

Claims

R. 417371 -1 13 Claims 1. Rotor of an electric machine (2) with a rotor shaft (4) rotatable about a rotor axis (3), with a rotor lamination stack (5) arranged on the rotor shaft (4), in which several rotor cooling channels (6) extending axially with respect to the rotor axis (3) are provided, which can be supplied with cooling fluid, in particular oil, via a hollow rotor shaft (4) for cooling the rotor (1), wherein the hollow rotor shaft (4) is fluidically connected to the rotor cooling channels (6) via at least one supply path (7) extending, in particular in a radial direction, through the rotor lamination stack (5), wherein the respective supply path (7) is formed in a central stack section (5m) between two outer stack sections (5a) of the rotor lamination stack (5), characterized in that In the respective rotor cooling channel (6) downstream of a channel inlet (26) into the rotor cooling channel (6) towards the two channel ends of the rotor cooling channel (6) at least one stagnation wall (20) is formed to stagnate the cooling fluid in the rotor cooling channel (6).

2. Rotor according to claim 1, characterized in that the respective baffle wall (20) in the respective rotor cooling channel (6) projects radially inwards in the radial direction with respect to the rotor axis (3) compared to a radially outer, in particular radially outermost, channel wall (6a) of the associated rotor cooling channel (6).

3. Rotor according to one of the preceding claims, characterized in that the respective baffle wall (20) in the respective rotor cooling channel (6) is formed on an end lamella (Le) of the rotor lamination stack (5), on a balancing disk (14) or on a sublamella below an end lamella (Le).

4. Rotor according to one of the preceding claims, characterized in that an end disk arrangement (10) is provided at each of the two end faces of the rotor lamination stack (5), comprising at least one outlet end disk (11) with fluid outlets (12) for the outflow of the cooling fluid from the rotor cooling channels (6), in particular for winding head cooling of a stator winding, wherein the respective fluid outlet (12) of the outlet end disk (11) of the respective end disk arrangement (10) is offset radially inwards relative to the associated rotor cooling channel (6) with respect to the rotor axis (3). R. 417371 -1 14 is that the baffle wall (20) for accumulating the cooling fluid in the associated rotor cooling channel (6) is formed at the outlet end disk (11) at the end of the associated rotor cooling channel (6).

5. Rotor according to claim 4, characterized in that the respective baffle wall (20) in the respective rotor cooling channel (6) extends in a radial direction with respect to the rotor axis (3) to a radially outer edge (12a) of the respective fluid outlet (12) of the outlet end disk (11).

6. Rotor according to one of claims 4 or 5, characterized in that the fluid outlets (12) of the outlet end disk (11) of the respective end disk arrangement (10) each have an outlet cross-section which is offset radially inwards relative to a channel cross-section of the associated rotor cooling channel (6) and is in particular smaller than the channel cross-section of the associated rotor cooling channel (6).

7. Rotor according to one of claims 4 to 6, characterized in that the outlet end disk (11) of the respective end disk arrangement (10) is an end lamella (Le) of the rotor lamination stack (5), wherein the respective end disk arrangement (10) in particular additionally comprises a balancing disk (14) which in particular has fluid passages (15) for conveying the cooling fluid from the fluid outlets (12).

8. Rotor according to one of claims 4 to 6, characterized in that the outlet end disk (11) of the respective end disk arrangement (10) is a balancing disk (14) which is arranged on an end face of the rotor lamination stack (5).

9. Rotor according to claim 8, characterized in that at least one seal (16) is provided between the outlet end disk (11) of the respective end disk arrangement (10), designed as a balancing disk (14), and the rotor lamination stack (5) to prevent leakage from the rotor cooling channels (6) into an annular gap formed between the outlet end disk (11) and the rotor lamination stack (5).

10. Rotor according to claim 7, characterized in that the respective end disk arrangement (10) additionally comprises at least one deflecting disk (13), R. 417371 -1 15 a. which is arranged between the outlet end disk (11) and the rotor lamination stack (5) and is in particular a special lamella of the rotor lamination stack (5), and / or b. on the radially extending deflection recesses (17) are formed, which each deflect the cooling fluid from the respective rotor cooling channel (6) radially inwards to the associated fluid outlet (12).

11. Rotor according to one of the preceding claims, characterized in that the rotor cooling channels (6) are formed in a semi-annular, arcuate, kidney-shaped, T-shaped or elongated shape in cross-section and / or are arranged in the circumferential direction between adjacent rotor poles.

12. Rotor according to one of the preceding claims, characterized in that several, in particular all, rotor cooling channels (6) are flow-connected via at least one annular distributor channel formed in the rotor (1), in particular in one of the end disk arrangements (10) and / or in the rotor lamination stack (5).

13. Rotor according to one of the preceding claims, characterized in that the rotor lamination stack (5) comprises a stack of lamellae (L) which are in particular bonded together.

14. Rotor according to one of the preceding claims, characterized in that the rotor (1) is enclosed by a rotor sleeve.

15. Electric machine (2) with a stator (40) having a stator winding (41) with winding heads (41h) and with a rotor (1) according to one of the preceding claims.

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