Electric machine with cooling

Abstract

The invention relates to a rotor (1) of an electric machine (10), in particular of a salient pole machine, the rotor comprising: a rotor body (2) which is rotatable about a rotor axis (400) and has a plurality of salient poles (3) and interposed rotor grooves (5); an excitation winding (4a) having a plurality of excitation coils (4), wherein each excitation coil (4) surrounds one of the salient poles (3); a plurality of groove closure elements (6) for supporting the excitation coils (4), wherein a groove closure element (6) is arranged in each rotor groove (5) between two coil sides (14) of two excitation coils (4), each groove closure element having two opposite support sides (15) for supporting the respective coil sides (14); and a rotor shaft (16) having a shaft cooling channel (17) for supplying cooling fluid, wherein at least one radial supply path (18) is formed in the rotor body (2) and fluidically connects the rotor grooves (5) to the shaft cooling channel (17), and wherein the at least one supply path (18) is formed in particular in an axial central region of the rotor body (2), characterized in that a flow-guiding structure (9) is formed on at least one support side (15) of at least one groove closure element (6) and is provided for guiding the flow of the cooling fluid that can be conducted into the rotor grooves (5).

Description

[0001] Description

[0002] title

[0003] Electric machine with cooling

[0004] State of the art

[0005] The present invention relates to a rotor of an electric machine. The invention also relates to an electric machine comprising a corresponding rotor. The electric machine is, for example, a salient-pole machine.

[0006] Salient-pole machines are known from the prior art. With this type of machine, securing the electrical windings of the poles is particularly important. For example, it is known to encapsulate the windings, which provides good fixation against the centrifugal forces that occur when the rotor rotates. However, encapsulation leads to reduced heat dissipation, so the removal of heat generated when the windings are energized must be ensured.

[0007] From DE 10 2019 212 391 A1 or DE 10 2020 119 679 A1, for example, a method is known for inserting a support element into the slots of the rotor to support the winding. Such a support element essentially forms the negative of two adjacent coils of the electrical winding and is inserted axially between each pair of adjacent coils. In this way, the coil is fixed in the tangential and radial directions.

[0008] Disclosure of the invention

[0009] The rotor according to the invention allows for reliable support of the excitation winding, whereby a cooling medium (such as oil or other dielectric medium) has optimal contact with the excitation winding. In particular, the surface of the excitation winding wetted by the cooling medium is maximized. Advantageously, high continuous power outputs can be achieved through the improved cooling.

[0010] The rotor is intended for use in an electric machine, particularly advantageously for a salient-pole machine. The rotor comprises a rotatable rotor body, an excitation winding, several slot closure elements, and a rotor shaft. The rotor body is rotatable about a rotor axis, which is, in particular, the central axis of the rotor shaft. The rotor body also has a plurality of salient poles and intervening rotor slots. The excitation winding comprises several excitation coils, each excitation coil enclosing one of the salient poles.

[0011] The slot closure elements serve to support the excitation coils. For this purpose, one slot closure element is arranged in each rotor slot between the two coil sides of two excitation coils. Each slot closure element has two opposing support surfaces for supporting the respective coil sides, so that these support surfaces rest against the respective excitation coils. This provides support for the excitation coils.

[0012] The rotor shaft has a shaft cooling channel for supplying cooling fluid. To convey the cooling fluid to the rotor slots of the rotor body, at least one radial supply path is formed in the rotor body, which connects the rotor slots to the shaft cooling channel. The at least one supply path is preferably formed in an axial central region of the rotor body (2).

[0013] Furthermore, it is provided that a flow guidance structure is implemented on at least one support side of at least one slot closure element. This flow guidance structure is designed to guide the flow of the cooling fluid that is directed into the rotor slots. This allows the cooling fluid to be directed straight to the excitation coils, ensuring optimal cooling of the excitation coils. The flow guidance structures of the slot closure elements ensure that the cooling fluid flows along the excitation coil in the best possible way to achieve optimal cooling.

[0014] The dependent claims describe preferred embodiments of the invention. Advantageously, a strip-shaped flow area is formed on each support side of a slot closure element. This flow area serves to create a cooling flow. It is provided that the flow area extends radially with respect to the rotor axis between an inner edge and an outer edge and has a radial height. Thus, the largest possible surface area of ​​the excitation coils can be wetted by the cooling fluid for cooling purposes.

[0015] The flow guidance structure features at least two cooling paths oriented in opposite directions relative to the rotor axis. These cooling paths lead to the two end faces of the rotor in opposite axial directions. This ensures optimal supply of cooling fluid. The opposing orientation of the cooling paths allows each path to absorb heat efficiently, thus achieving high cooling performance.

[0016] The respective slot closure element advantageously features a foot section. Between the foot section of the slot closure element and a slot base of the respective rotor slot, an axially extending slot base path is formed, which is flow-connected upstream to the supply path. The slot base path serves, in particular, to collect the cooling fluid from the supply path and to distribute the cooling fluid to the cooling paths.

[0017] In one embodiment, the flow guidance structure comprises radially oriented cooling paths. These cooling paths extend obliquely towards one of the two end faces of the rotor with respect to the rotor axis. The cooling paths are designed as groove-shaped recesses in the respective support face and are flow-connected upstream to the groove base path. The radial shape ensures a uniform distribution of the cooling fluid, resulting in consistent cooling along the flow guidance structure.

[0018] It is particularly advantageous for several of the cooling paths to be connected upstream to the main groove path via a distribution channel. For example, the distribution channel is curved. It is advantageously provided that the distribution channel is connected to the main groove path via several separate supply connections. The distribution channel thus allows for the branching of the radially oriented cooling paths, ensuring that each cooling path is optimally supplied with cooling fluid via the distribution channel. The appropriate amount of cooling fluid can be fed from the main groove path into the distribution channel by adjusting the number of supply connections.

[0019] The cooling paths are preferably connected to adjacent cooling paths in a head section of the groove closure element. For this purpose, passages are provided between the groove-shaped recesses, by means of which the connection is established. This allows, in particular, reliable drainage of the cooling fluid. Furthermore, temperature equalization of the cooling fluid at the passages is enabled to achieve a uniform cooling effect.

[0020] In an alternative embodiment, the flow guidance structure has guide ribs arranged at intervals along the axial direction with respect to the rotor axis. These guide ribs extend radially, forming cooling paths between them. Upstream, these cooling paths are connected to the groove base path. This causes the cooling fluid to accumulate at the guide ribs until it can overflow. In this way, a uniform cooling effect is achieved across the respective support side of the groove closure elements.

[0021] Preferably, the guide ribs are designed and / or arranged to form two meandering cooling paths running in opposite axial directions. Preferably, the radial height of each guide rib is shorter than the height of the flow area. The meandering shape ensures that the cooling fluid is guided uniformly along the entire height of the area.

[0022] Two sets of guide ribs are particularly advantageous. One set of first guide ribs extends radially inwards from the outer edge of the flow area, and a second set of guide ribs extends radially outwards from the inner edge. The cooling path between the ribs is preferably meandering. In particular, the first and second guide ribs are arranged alternately in the axial direction. The rib height of the first and second guide ribs is preferably progressively shorter from a central area towards the end faces of the rotor. Thus, the greatest flow resistance is present upstream of the cooling path, decreasing downstream. This enables uniform heat absorption by the cooling fluid along the cooling path.

[0023] The guide ribs are designed to allow flow, particularly in the axial direction, and create flow resistance. This forms cooling paths, some of which run radially, so that the cooling paths run around the guide ribs. As a result, the cooling fluid is guided radially, ensuring a uniform cooling effect along the entire height of the flow area.

[0024] In an alternative configuration, the guide ribs extend radially with respect to the rotor axis across the entire height of the flow area. This creates radially oriented cooling paths. These cooling paths are specifically separated from one another, thus allowing for independent cooling. Alternatively, the cooling paths are interconnected, enabling temperature equalization for uniform cooling of the excitation winding.

[0025] The guide ribs each advantageously feature at least one passage. This passage serves to connect adjacent cooling paths in the axial direction. Each passage is designed to run either along the axial direction relative to the rotor axis or obliquely in both the axial and radial directions. The orientation of the passage allows for the adjustment of flow characteristics. Thus, the inclusion of passages enables optimal distribution of the cooling effect across the flow path.

[0026] Each cooling path is advantageously connected to the groove base path via its own feed connection. Alternatively, a single feed connection is provided for the flow connection of all cooling paths to the groove base path. This single feed connection is preferably located either at an axial edge of the groove closure element or in an axial central region of the groove closure element. Preferably, the two support sides of each groove closure element are integrally connected via a film hinge. The film hinge forms, in particular, the base section of the groove closure element. This makes the groove closure element easy to handle and allows for quick and easy insertion into the rotor groove. Rotor assembly is therefore simplified.

[0027] Each slot closure element advantageously closes one slot of the respective rotor slot. This ensures complete support of the excitation winding. The rotor therefore exhibits high stability, and in particular, the risk of the excitation winding slipping is minimized. Furthermore, the cooling fluid is reliably guided within the rotor slot, thus optimizing cooling of the excitation winding.

[0028] The rotor body is preferably enclosed by a rotor sleeve. The rotor sleeve holds the slot locking elements within the rotor slot and thus serves to support them. This gives the rotor a high degree of stability. In particular, the excitation winding is reliably held in the desired position on the rotor by the slot locking elements and the rotor sleeve.

[0029] The invention also relates to an electric machine, in particular a salient-pole machine. The electric machine comprises a stator and a rotor driven by the stator. The rotor is designed as described above. This ensures optimal support of the excitation winding for the rotor, while also guaranteeing reliable cooling.

[0030] Brief description of the drawings

[0031] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawing shows:

[0032] Figure 1 is a schematic view of an electrical machine according to an embodiment of the invention, Figure 2 is a schematic detail view of a partial area of ​​a

[0033] Rotors of the electric machine according to the embodiment of the invention,

[0034] Figure 3a shows a schematic side view of a first alternative of a slot closure element of the rotor of the electric machine according to the embodiment of the invention.

[0035] Figure 3b shows a schematic top view of the first alternative of the slot locking element of the rotor of the electric machine according to the embodiment of the invention.

[0036] Figure 3c shows a schematic view of a first alternative flow model of the slot closure element of the rotor of the electric machine according to the embodiment of the invention.

[0037] Figure 4a shows a schematic view of a second alternative of a slot closure element of the rotor of the electric machine according to the embodiment of the invention.

[0038] Figure 4b shows a schematic view of a second alternative flow model of the slot closure element of the rotor of the electric machine according to the embodiment of the invention.

[0039] Figure 5 is a schematic view of a third alternative of a

[0040] slot locking element of the rotor of the electric machine according to the embodiment of the invention,

[0041] Figure 6 is a schematic view of a fourth alternative of a

[0042] slot locking element of the rotor of the electric machine according to the embodiment of the invention,

[0043] Figure 7 is a schematic view of a fifth alternative of a

[0044] Slot locking element of the rotor of the electric machine according to the embodiment of the invention, Figure 8 a schematic view of a sixth alternative of a

[0045] slot locking element of the rotor of the electric machine according to the embodiment of the invention, and

[0046] Figure 9 shows a schematic view of a seventh alternative of a

[0047] Slot locking element of the rotor of the electric machine according to the embodiment of the invention.

[0048] Embodiments of the invention

[0049] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0050] Figure 1 schematically shows an electric machine 10 according to an embodiment of the invention, which in this embodiment is a salient-pole machine. The electric machine 10 has a stator 11 and a rotor 1 driven by the stator 11.

[0051] The rotor 1 has a rotor axis 400, with a radial direction 200 extending perpendicular to the rotor axis 400. The rotor 1 also has a rotor body 2 rotatable about the rotor axis 400, with a plurality of salient poles 3 and intervening rotor slots 5. Furthermore, an excitation winding 4a is provided, which has several excitation coils 4. Each excitation coil 4 surrounds one of the salient poles 3. Figure 2 schematically shows detail X as marked in Figure 1, wherein detail X shows a rotor slot 5 with partial sections of two excitation coils 4 arranged therein.

[0052] The rotor 1 also has several slot closure elements 6 for supporting the excitation coils 4. The slot closure elements 6 are made of, for example, plastic. In each rotor slot 5, a slot closure element 6 is arranged between two coil sides 14 of two excitation coils 4. Each slot closure element 6 closes one slot of the respective rotor slot 5. Each slot closure element 6 has two opposing support sides 15 for supporting the respective coil sides 14. In this way, the excitation coils 4 are supported in the rotor slots 5. The excitation coils 4 are thus reliably held at designated locations on the rotor body 2. This allows for optimal magnetic flux between the rotor and stator 11. To improve the stability of the rotor 1, the rotor body 2 is enclosed by a rotor sleeve 21.

[0053] The rotor 1 further comprises a rotor shaft 16. The rotor shaft 16 is provided with a shaft cooling channel 17, which is designed for supplying cooling fluid. At least one radial supply path 18 is formed in the rotor body 2, which connects the rotor slots 5 to the shaft cooling channel 17. The at least one supply path 18 is formed in an axial central region of the rotor body 2.

[0054] The supply path 18 allows cooling of the excitation winding 4a by supplying cooling fluid to the excitation coils 4. The slot closure elements 6 serve to guide the cooling fluid, optimizing the cooling effect. For this purpose, a flow guidance structure 19 is provided on at least one support side 15, ideally on both support sides 15, of the slot closure elements 6. This structure is designed to guide the flow of the cooling fluid that can be directed into the rotor slots 5. Thus, the cooling fluid entering the respective rotor slot 5 is optimally distributed along the respective coil side 14 by the flow guidance structure 19. This results in uniform cooling of the excitation coils 4.

[0055] The design of the flow guidance structure 19 always allows for an optimal distribution of the cooling fluid, and the flow guidance structure 19 can be configured in different ways. Figures 3a and 3b show a first principle, in which radial cooling paths 12 are formed by the flow guidance structure 19. Figures 4a and 4b show a second principle, in which meandering cooling paths 12 are formed by the flow guidance structure 19.

[0056] Figure 3a schematically shows a side view and Figure 3b shows a top view of the slot closure element 6, with the flow guidance structure 19 visible on the support side 15 of the slot closure element 6. Figure 3c shows an exemplary flow model. In the examples of a first alternative shown in Figures 3a to 3c, radial cooling paths 12 are formed. On each support side 15 of a slot closure element 6, a strip-shaped flow region 19 is formed to create a cooling flow. The flow region 19 extends in the radial direction 200 with respect to the rotor axis 400 between a radial inner edge 19a and a radial outer edge 19b and has a region height h in the radial direction 200.

[0057] The flow-guiding structure 19 has two cooling paths 12 oriented in the axial direction 100 with respect to the rotor axis 400, opposite each other. The cooling paths 12 are radially oriented and extend in opposite axial directions 100 to the two end faces of the rotor 1, with each cooling path 12 leading obliquely to one of the two end faces of the rotor 1 with respect to the rotor axis 400. The cooling paths 12 are formed as groove-shaped recesses 9 in the respective support surface 15. The groove-shaped recesses 9 have a depth in the tangential direction 300, oriented perpendicular to the radial direction 200 and the axial direction 100, of between 0.1 mm and 1.0 mm.

[0058] Each slot closure element 6 has a foot section 13a. Between the foot section 13a of the slot closure element 6 and a slot base 5a (see Figure 2) of the respective rotor slot 5, a slot base path 20 extending in the axial direction 100 is formed, which is flow-connected upstream to the supply path 18. The radially extending cooling paths 12 are flow-connected upstream to the slot base path 20. Thus, cooling fluid can flow from the supply path via the slot base path 20 to the cooling paths 12.

[0059] To achieve optimal distribution of the cooling fluid to the cooling paths 12, several of the cooling paths 12 are connected upstream to the groove base path 20 via an arc-shaped distribution channel 8. Figures 3a and 3b show different variations of this connection. The distribution channel 8 itself is connected to the groove base path 20 via several separate supply connections 20a. Alternatively or additionally, at least some of the cooling paths 12 are directly connected to the groove base path 20 via separate auxiliary supply connections 20b.

[0060] Furthermore, the cooling paths 12 in a head section 13b of the groove closure element 6 are flow-connected to adjacent cooling paths 12. This is achieved by means of passages 12a between the groove-shaped recesses 9, which form the cooling paths 12. These passages 12a allow for equalization of the flows through the cooling paths and for the cooling fluid to be guided outwards in the axial direction 100.

[0061] The radial design of the cooling paths 12 ensures a uniform distribution of the cooling fluid along the respective coil side 14 of the excitation coil 4. The excitation coil 4 is thus reliably and uniformly cooled within the rotor slot 5. In addition, the slot closure elements 6 provide a secure hold for the individual excitation coils 4, resulting in high stability of the rotor 1.

[0062] Each slot closure element 6 has two support sides 15 which bear against opposite reel sides 14 of two excitation reels 4 within the same rotor slot 5. The two support sides 15 of the respective slot closure element 6 are integrally connected to each other via a film hinge 21. The film hinge 21 forms the foot section 13a of the slot closure element 6.

[0063] Figure 4a schematically shows a side view of the groove closure element 6, with the flow guidance structure 19 visible on the support side 15 of the groove closure element 6. Figure 4b shows an exemplary flow model. In the example shown in these figures, meandering cooling paths 12 are formed. The basic structure of the groove closure elements 6 is the same as in the first alternative described above. Only the shape of the cooling channels 12 differs.

[0064] In the second alternative, the flow guidance structure 9 has guide ribs 7a, 7b spaced apart from each other in the axial direction 100 with respect to the rotor axis 400. The guide ribs 7a, 7b extend in the radial direction 200, and cooling paths 12 are formed between them. A groove base path 20 is formed as described above, and the cooling paths 12 are flow-connected upstream to the groove base path 20. For example, the tangential dimension of the guide ribs 7a, 7b 300 is between 0.1 mm and 1.0 mm.

[0065] The guide ribs 7a, 7b comprise a set of first guide ribs 7a and a set of second guide ribs 7b. The first guide ribs 7a extend inwards in a radial direction 200 from the outer edge 19b of the flow region. The second guide ribs 7b extend outwards in a radial direction 200 from the inner edge 19a. In this way, the guide ribs 7a, 7b form two meandering cooling paths 12 extending in opposite axial directions 100. The respective rib height k of the guide ribs 7a, 7b in the radial direction 200 is shorter than the region height h of the flow region. The rib height k of the first guide ribs 7a and the second guide ribs 7b is designed to be progressively shorter from a central region towards the end faces of the rotor 1.

[0066] The guide ribs 7a, 7b are designed to allow flow in the axial direction 100 and create flow resistance against flow in the axial direction 100. In this way, the guide ribs 7a, 7b deflect the cooling fluid in the radial direction 200, ensuring optimal cooling by the cooling fluid across the entire height h of the area. The guide ribs 7a, 7b also serve to adjust and vary the flow cross-section and thus the flow resistance in the axial direction 100. Therefore, the guide ribs 7a, 7b allow for uniform cooling along the entire respective support surface 15.

[0067] Figure 5 schematically shows a third alternative of a slot closure element for the rotor 1 of the electric machine 10 according to the embodiment of the invention. In this alternative, guide ribs 7 are provided analogously to the second alternative, but the arrangement of the guide ribs 7 differs. The guide ribs 7 extend in the radial direction 200 over the entire height h of the area.

[0068] Each guide rib 7 has two passages 12a extending in the axial direction 100. The passages 12a allow the cooling fluid to flow in the axial direction 100 between the cooling paths 12 extending in the radial direction 200. A single supply connection 20a connects an axially outer cooling path 12 to the groove base path 20, so that cooling fluid flows from the supply connection 20a along the entire dimension of the flow area 19 in the axial direction 100 through the passages 12a. Figure 6 schematically shows a view of a fourth alternative of a groove closure element 6 of the rotor 1 of the electric machine 10 according to the embodiment of the invention. The only difference to the third alternative is that each guide rib has 7 obliquely oriented passages 12a extending both in the radial direction 200 and in the axial direction 100.Furthermore, this example shows three passages 12a per guide rib 7 instead of two.

[0069] Figure 7 is a schematic view of a fifth alternative slot closure element 6 of the rotor 1 of the electric machine 10 according to the embodiment of the invention. The difference from the fourth alternative is the arrangement of the supply connection 20a. In this alternative, the supply connection 20a is arranged in the axial direction 100 in the center of the flow area 19. This results in two main flow directions opposite in the axial direction 100. The passages 12a are oriented obliquely radially outwards with respect to the supply connection 20a.

[0070] Figure 8 schematically shows a sixth alternative of a groove closure element.

[0071] 6 of the rotor 1 of the electric machine 10 according to the embodiment of the invention. The difference to the fifth alternative is that instead of a single feed opening 20a, several feed openings 20a are provided, so that each cooling path 12, which runs in radial direction 200 between two guide ribs 7, has its own flow connection with the groove base path 20.

[0072] Figure 9 is a schematic view of a seventh alternative of a slot closure element 6 of the rotor 1 of the electric machine 10 according to the embodiment of the invention. In this alternative, the guide ribs

[0073] 7 are continuous and have no openings 12a. Thus, several independent cooling paths 12 are present, each with its own supply opening 20a for connection to the groove base path 20. Mixing of the cooling fluid in the cooling paths 12 is not intended.

[0074] The guide ribs 7 allow for the simple and optimal distribution of a cooling fluid along the coil sides 14 of the excitation coils 4. The guide ribs 7 can be easily designed differently to adapt the fluid flow of the cooling fluid to the specific conditions of the excitation winding. Thus, the slot closure element 6 can be optimally adapted to a specific application.

Claims

Claims 1. Rotor (1) of an electric machine (10), in particular a salient-pole machine, comprising - a rotor body (2) rotatable about a rotor axis (400) with a plurality of salient poles (3) and intervening rotor slots (5), - an excitation winding (4a) with several excitation coils (4), wherein each excitation coil (4) surrounds one of the salient poles (3), - several slot closure elements (6) for supporting the excitation coils (4), wherein in each rotor slot (5) between two coil sides (14) of two excitation coils (4) a slot closure element (6) is arranged, each having two opposing support sides (15) for supporting the respective coil sides (14), and - a rotor shaft (16) with a shaft cooling channel (17) for supplying cooling fluid, wherein at least one radial supply path (18) is formed in the rotor body (2) which connects the rotor slots (5) to the shaft cooling channel (17) in a flow direction, wherein the at least one supply path (18) is formed in particular in an axial central region of the rotor body (2), characterized in that a flow guidance structure (9) is provided on at least one support side (15) of at least one slot closure element (6), which is provided for guiding the flow of the cooling fluid that can be directed into the rotor slots (5).

2. Rotor (1) according to claim 1 , characterized in that on each support side (15) of a slot closure element (6) a strip-shaped flow area (19) is formed to create a cooling flow, wherein the flow area (19) extends in a radial direction (200) with respect to the rotor axis (400) between an inner edge (19a) and an outer edge (19b) and has an area height (h) in a radial direction (200).

3. Rotor (1) according to one of the preceding claims, characterized in that the flow guidance structure (9) comprises at least two cooling paths (12) opposite in the axial direction (100) with respect to the rotor axis (400), which lead in opposite axial direction (100) to the two end faces of the rotor (1).

4. Rotor (1) according to claim 3, characterized in that the respective slot closure element (6) has a foot section (13a), wherein between the foot section (13a) of the slot closure element (6) and a slot base (5a) of the respective rotor slot (5) a slot base path (20) extending in the axial direction (100) is formed, which is flow-connected upstream with the feed path (18).

5. Rotor (1) according to claim 4, characterized in that the flow guidance structure (19) comprises radially extending cooling paths (12), - which each run obliquely towards one of the two end faces of the rotor (1) with respect to the rotor axis (400), - which are formed as groove-shaped recesses (9) in the respective support side (15), and - which are flow-connected upstream with the groove bottom path (20).

6. Rotor (1) according to claim 5, characterized in that several of the cooling paths (12) are flow-connected upstream via a, in particular arc-shaped, distributor channel (8) to the groove bottom path (20), wherein the distributor channel (8) is flow-connected to the groove bottom path (20), in particular via several separate feed connections (20a).

7. Rotor (1) according to claim 5 or 6, characterized in that the cooling paths (12) in a head section (13b) of the slot closure element (6) are flow-connected with adjacent cooling paths (12), in particular by means of passages (12a) between the slot-shaped recesses.

8. Rotor (1) according to claim 4, characterized in that the flow guidance structure (19) is axially (100) with respect to the The rotor axis (400) has guide ribs (7, 7a, 7b) arranged at a distance from each other, which run in a radial direction (200) and between which cooling paths (12) are formed, which are flow-connected upstream with the groove bottom path (20).

9. Rotor (1) according to claim 8, characterized in that the guide ribs (7a, 7b) are designed and / or arranged to form two meandering cooling paths (12) extending in opposite axial directions (100), wherein a respective rib height (k) of the guide ribs (7a, 7b) in the radial direction (200) is in particular shorter than the area height (h) of the flow area.

10. Rotor (1) according to claim 8 or 9, characterized in that two sets of guide ribs (7a, 7b) are formed, wherein a set of first guide ribs (7a) extends inwards in a radial direction (200) from the outer edge (19b) of the flow area, and wherein a set of second guide ribs (7b) extends outwards in a radial direction (200) from the inner edge (19a).

11. Rotor (1) according to claim 10, characterized in that the rib height (k) of the first and second guide ribs (7a, 7b) are progressively shorter from a central area towards the end faces of the rotor (1).

12. Rotor (1 ) according to claims 4 to 11 , characterized in that the guide ribs (7a, 7b) are flowable in the axial direction (100) and form a flow resistance against a flow in the axial direction (100).

13. Rotor (1) according to claim 8, characterized in that the guide ribs (7) extend along a radial direction (200) with respect to the rotor axis (400) over the entire area height (h) in order to form cooling paths (12) extending in a radial direction (200).

14. Rotor (1) according to claim 13, characterized in that the guide ribs (7) each have at least one passage (12a) to allow cooling paths (12) adjacent in the axial direction (100) to connect the flow, wherein each passage (12a) runs along the axial direction (100) with respect to the rotor axis (400) or obliquely in both the axial direction (100) and the radial direction (200).

15. Rotor (1) according to claim 13 or 14, characterized in that each cooling path (12) is flow-connected to the groove base path (20) via its own feed connection (20a) or that a single feed connection (20a) is provided for flow-connecting all cooling paths (12) to the groove base path (20), which is formed on an axial edge of the groove closure element (6) or in an axial center of the groove closure element (6).

16. Rotor (1) according to one of the preceding claims, characterized in that the two support sides (15) of the respective groove closure element (6) are integrally connected to each other via a film hinge (21), which in particular forms the foot section (13a) of the groove closure element (6).

17. Rotor (1) according to one of the preceding claims, characterized in that the respective slot closure element (6) closes one slot of the respective rotor slot (5).

18. Rotor (1) according to one of the preceding claims, characterized in that the rotor body (2) is enclosed by a rotor sleeve (21).

19. Electric machine (10), in particular salient pole machine, comprising a stator (11) and a rotor (1) driven by the stator (11) according to one of the preceding claims.

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