External-rotor machine, in particular external-rotor motor or external-rotor generator, having a rotor with a shaft mounted internally in a stator tower of the stator or stator bushing, in which cooling channels are formed, in which cooling channels a fluid absorbs and dissipates waste heat from the machine, and in particular from the stator and the electromagnetic system thereof

Abstract

The invention relates to a rotating electrical machine with an external-rotor structure, in particular to an electrical external-rotor motor or generator, having a rotor with a shaft mounted within a stator tower of the stator. Between a stator tower inner wall, which serves to receive a bearing, and a stator tower outer wall, on which the electromagnetic system is mounted, one or more cooling channels are formed in the stator bushing surrounding the stator tower. These cooling channels serve to guide a flowing fluid through the inner region of the machine, said fluid absorbing and dissipating waste heat from the electromagnetic system.

Description

[0001] "External rotor machine, in particular external rotor motor or external rotor generator, with a rotor with shaft which is mounted inside in a stator tower of the stator or stator bushing, in which cooling channels are formed in which a fluid absorbs and carries away waste heat from the machine and in particular from the stator and its electromagnetic system"

[0002] The present invention relates to a rotating electric machine of external rotor design (hereinafter referred to as an external rotor machine), in particular an electric external rotor motor or generator, especially for turbomachinery such as fans or wind turbines, but also for applications in electromobility. The machine has a rotor with a shaft that is supported internally in a stator tower of the stator or stator bushing. Cooling channels are formed in the stator tower, running between an inner wall facing the rotor, which serves as the bearing housing, and an outer wall to which the electromagnetic system (in particular consisting of the stator core and stator winding) is attached. A fluid can circulate in these cooling channels, absorbing and dissipating waste heat from the electric machine.

[0003] Technical task

[0004] Due to their design, external rotor motors have significant disadvantages in heat dissipation from the stator compared to internal rotor motors. The stator, which is the primary heat generator, is located inside the rotor and surrounded by the rotor. This makes convective cooling considerably more difficult, and the heat must be dissipated to the outside via the stator bushing, which is more complex. This leads to high thermal resistance and consequently to overheating of thermally critical components such as bearings or the stator winding. These disadvantages are exacerbated with increasing size, high protection ratings, or in applications with high ambient temperatures.

[0005] Current technology typically involves heat dissipation via external housing surfaces or external cooling systems. Internal cooling concepts are rare and technically complex. Known solutions often require additional components such as heat sinks or external air ducts, which increases the overall size and complexity. Furthermore, there is the mechanical challenge of designing the supporting structure (stator bushing) to reliably accommodate the rotor bearings and assembly forces. A thermally optimized yet mechanically robust design is therefore particularly demanding.

[0006] Solution of the technical problem

[0007] The invention solves these problems with an external rotor machine in which internal cooling channels, through which a fluid flows, are provided in the stator tower. These channels run between the inner wall of the stator tower (for bearing support) and the outer wall (for housing the electromagnetic system). The fluid, preferably air or liquid, flows axially along the axis of rotation and carries heat away directly from the interior of the stator.

[0008] This significantly shortens the thermal path. Critical components such as bearings or windings are directly protected. The cooling system according to the invention can be integrated into closed, encapsulated machines, enabling a high degree of protection (e.g., IP55 or higher) without relying on open rotor designs or potting compounds.

[0009] Compared to the prior art, which uses open rotors for air passage, the solution according to the invention eliminates the need for continuous rotor openings, thus providing better sealing against dust and moisture. Furthermore, the elimination of stator potting offers advantages in terms of repairability and recycling.

[0010] Constructive design and variants

[0011] The stator bushing can essentially consist of a radially oriented stator flange and an axially oriented stator tower. The cooling channels are preferably integrated, at least partially, into the stator tower and run axially. The stator tower can be extruded, cast, or machined; hybrid designs are also conceivable (e.g., cast-in inlays or tube systems). A particularly preferred design is an extruded stator tower with continuous or segmented cooling channels running within a thermally conductive profile cross-section. Such extruded profiles enable efficient cooling through defined flow channels and simultaneously offer high dimensional accuracy for precise bearing guidance and winding assembly. Furthermore, the extruded tower, with its smooth or grooved outer contour, can directly serve to fix and positively engage the stator lamination stack.

[0012] Unless both components are formed as a single casting, the connection between the stator tower and stator flange can be achieved by shrink-fitting, press-fitting, bonding, or potting. Shrink-fitting into a suitably machined bore of the die-cast stator flange is particularly advantageous for extruded towers. This allows for cost-effective mass production with high dimensional accuracy and mechanical stability.

[0013] Liquid cooling (e.g., with water or coolant) from a device cooling system (e.g., a heat pump or a vehicle cooling system) is also provided. The cooling system can be designed in a straight line or a meandering pattern, for example, in loops.

[0014] The design of the stator tower as an extruded component, as shown in the embodiments according to Fig. 9, is particularly advantageous. Extrusion allows for precise and resource-efficient manufacturing of the cooling channels with high dimensional accuracy and clearly defined flow cross-sections. The elimination of complex molds or subsequent machining steps enables economical production even for large quantities.

[0015] Furthermore, the extruded outer contour enables a positive-locking fixation of the stator lamination stacks, which improves both thermal connectivity and simplifies assembly. Integration into a two-part stator support concept (stator bushing concept) (e.g., by shrinking a stator tower into a cast stator flange) allows the advantages of different manufacturing techniques to be combined. Validation is achieved through simulation and prototype construction.

[0016] Simulations on a fan motor with a 200 mm air gap diameter showed a temperature reduction of 25 K at the winding and bearings through the use of the cooling channels in the stator tower at a pressure of 150 Pa for the flow of ambient air (conveying air) through the cooling channels.

[0017] A real-world prototype with a 150 mm air gap diameter achieved a temperature reduction of over 40 K at the stator winding when ambient air (conveyor air) flowed through the cooling channels at a pressure of 100 Pa. At the same temperature level, this enabled a performance increase of almost 50% through increased rotational speed with the same fan impeller.

[0018] Manufacturing aspects

[0019] Cooling channels can be formed by die casting with cores, machining, or by using inlays (e.g., copper or aluminum tubes). Extruded hollow profiles with integrated cooling channels are particularly advantageous, as they offer both high thermal performance and cost-effective mass production. The external connection between the stator tower and stator flange requires tight tolerances (e.g., IT7-IT9) to avoid the need for further machining. If necessary, the outer circumference can be machined. The winding zone should be machined anyway for quality assurance. A circular outer contour is preferred.

[0020] Positive-locking integration of the stator lamination stacks

[0021] The stator tower can also be externally ribbed or grooved, allowing for positive-locking assembly of the stator lamination stacks. This increases mechanical strength and reduces the effort required for bonding or potting. There are various ways to advantageously design and further develop the teaching of the present invention. For this purpose, reference is made, on the one hand, to the dependent claims following claims 1 and 7, and on the other hand, to the following explanation of preferred embodiments with reference to the drawings. In conjunction with the description of these preferred embodiments, generally advantageous embodiments and further developments of the invention are also explained with reference to the drawings.

[0022] The drawing shows:

[0023] Fig. 1 shows a perspective view from the rotor side of an embodiment of a rotating electric machine according to the invention in external rotor design with an internal cooling flow guide that runs through cooling channels in the stator bushing,

[0024] Fig. 1a shows in a view comparable to Fig. 1 exclusively the stator bushing or the support structure of the stator of the embodiment according to Fig. 1,

[0025] Fig. 2 shows a perspective view from the stator side of the embodiment of a rotating electric machine in external rotor design according to Fig. 1.

[0026] Fig. 2a shows, in a view comparable to Fig. 2, only the stator bushing or the support structure of the stator of the embodiment according to Fig. 1 and Fig. 2.

[0027] Fig. 3 shows a side view and a section in a plane through the axis of rotation of the embodiment of a rotating electric machine in external rotor design according to Figs. 1 and 2.

[0028] Fig. 4, in perspective view obliquely from the rotor side and in section on a plane through the axis of rotation, shows the embodiment of a rotating electric machine in external rotor design according to Figs. 1 to 3, Fig. 4a an enlarged detail view according to Fig. 4 in the area of ​​the rotor-side bearing,

[0029] Fig. 5 shows a perspective view obliquely from the stator side and in section on a plane through the axis of rotation, the embodiment of a rotating electric machine in external rotor design according to Figs. 1 to 4.

[0030] Fig. 6 shows, in a view parallel to the axis of rotation from the stator side, the embodiment of a rotating electric machine in external rotor design according to Figs. 1 to 5.

[0031] Fig. 7 shows, in a view parallel to the axis of rotation from the rotor side, the embodiment of a rotating electric machine in external rotor design according to Figs. 1 to 6.

[0032] Fig. 8 shows a further embodiment of a rotating electric machine according to the invention in an external rotor design, in which the internal cooling channels in the stator tower are formed by tubes that are cast into the stator tower.

[0033] Fig. 8a shows an enlarged detail view according to Fig. 8 in the area of ​​the stator tower,

[0034] Fig. 9, in a perspective view obliquely from the stator side and in section on a plane through the axis of rotation, shows another embodiment of a rotating electric machine in external rotor design according to the invention, wherein the stator tower is essentially formed as an extruded part in which the internal cooling channels are integrated, which is, for example, shrunk or pressed into the stator flange or the stator bushing, Fig. 9a is an enlarged detail view according to Fig. 9 in the area of ​​the stator tower.

[0035] Figures 1 to 7, as well as 1a, 2a and 4a, show in various representations and views an embodiment of an electric external rotor machine, here an electric external rotor motor 1, with internal cooling channels 4 in the stator socket 20 of the stator 2. In the exemplary embodiment, axially aligned cooling channels 4 run in the stator tower 21 of the stator socket 20 approximately parallel to the axis of rotation of the rotor 3, specifically between an inner wall 36 and an outer wall 39 of the stator tower 21.

[0036] The internal cooling channels 4 of the rotating electric machine 1 can be permeated by a gaseous and / or liquid fluid, particularly during machine operation, thereby absorbing and dissipating heat generated within the electric machine 1. This significantly improves the cooling of the electric machine. Consequently, at the same ambient temperature and with the same machine performance data, such as the same rotational speed and drive torque, the temperatures at one or more components, such as the stator winding 9, the bearings 12, 13, electrical power components 22, or generally of electronic components in the electronic housing 18, are lower.

[0037] Conversely, as a result of the flow through the internal cooling channels 4, with the same machine performance data, such as the same speed and the same drive torque, at maximum permissible temperatures of corresponding components such as the stator winding 9, the bearings 12, 13, electrical power components 22 or generally of electronic components in the electronic housing 18, the electric machine 1 can be operated at higher ambient temperatures.

[0038] Furthermore, due to the flow through the internal cooling channels 4, the electric machine 1 can be operated at higher performance parameters, such as drive torque, speed, or machine power, at the same ambient temperatures and at the maximum permissible temperatures of corresponding components, such as the stator winding 9, the bearings 12, 13, electrical power components 22, or generally of electronic components in the electronics housing 18. The electric machine 1 is specifically composed of a stator 2 and a rotor 3, with the rotor 3 being mounted on the stator 2. Mounting devices 27 are provided on the stator 2 for attaching the electric machine 1 to an external mounting or structure. Mounting devices 28 are provided on the rotor 3 for attaching an external rotor, e.g., a turbomachine impeller, to the electric machine 1 or to its rotor 3.Such fastening provisions 27, 28 can be of various types, but sufficient stability and strength must be ensured in the corresponding load introduction paths.

[0039] For example, when the electric machine 1 is used in turbomachinery, the entire weight of the turbomachine impeller, which is attached to the rotor 3 at the mounting points 28, and the electric machine 1, superimposed with further reaction forces such as inertial forces, aerodynamic forces, etc., is transferred via the mounting points 28 into the higher-level structure. This means that the force transmission path via rotor 3, its bearing on the stator 2, through the stator 2 to the mounting points 28 must be reliably ensured. Vibrations or excessive deformations during operation must be avoided.

[0040] The supporting structure of the stator 2 is the stator bushing 20, which is also shown separately in Fig. 1a and Fig. 2a. The stator bushing 20 is essentially composed of a stator flange 16 and a stator tower 21. The stator flange 16 extends, similar to a plate, primarily in a radial direction from the inside (near the axis) to the outside (far from the axis) and has an outer edge 34. The stator tower 21 extends from a more inner region of the stator flange 16 essentially parallel to the axis of rotation.

[0041] The electromagnetic system of the stator 2 is attached to the outer wall 39 of the stator tower 21. This consists essentially of the stator lamination stack 8 and the stator windings 9, which are shown schematically as blocks in the figures, and the associated insulating layer 37.

[0042] The bearing seat 30 of the rotor-side bearing 13 and the bearing seat 35 of the stator-side bearing 12 are located in the area of ​​the inner wall 36 of the stator tower 21. The rotor 3 of the electric machine 1 is supported in the stator tower 21 by means of these bearings 12 and 13 via its shaft 19. The shaft 19 is radially opposite the inner wall 36 of the stator tower 21.

[0043] The stator tower 21 thus supports the electromagnetic system of the stator 2, consisting essentially of the stator lamination stack 8 and the stator windings 9 and the associated insulating layer 37, but also the rotor 3 with other external components attached to the rotor 3. As a result, the stator tower 21 is subjected to high force and torque stresses at the stator socket 20 of the stator 2. In particular, the transition area between the stator tower 21 and the stator flange 16 of the stator socket 20 must be sufficiently robust to prevent cracking or excessive deformation.

[0044] In the external rotor machine, the rotor 3 radially surrounds at least the electromagnetic system, which essentially consists of the stator lamination stack 8, the stator windings 9, and the associated insulating layer 37. Nevertheless, the shaft 19 is provided centrally on the rotor 3 so that the rotor 3 can be supported in the stator tower 21 with the bearings 12, 13.

[0045] The shaft 19 (advantageously steel) is connected to the body of the rotor (advantageously aluminium) by means of the cast-in insert bushing 38 (e.g. Fig. 4a).

[0046] The rotor 3 surrounds the electromagnetic system of the stator, consisting of stator windings 9 and the stator lamination stack 8. In the exemplary embodiment, the electromagnetic system of the rotor 3 itself consists of permanent magnets 10 and a surrounding return ring 11, since in the exemplary embodiment it is an EC motor 1.

[0047] Versions as AC motors or generators are also conceivable.

[0048] A particular challenge with external rotor machines is cooling, i.e., the dissipation of the inevitably generated waste heat. A large portion of this waste heat originates in the electromagnetic system of the stator 2, specifically the stator windings 9 and the stator lamination stack 8. The rotor 3, which surrounds the electromagnetic system of the stator 2, significantly hinders the unimpeded dissipation of this heat to the outside. Especially in electrical machines 1 with a high degree of protection, the electromagnetic system must be well shielded from the environment to prevent, for example, the ingress of moisture.

[0049] An air gap is necessarily provided between the electromagnetic system of the stator 2, specifically the stator lamination stack 8, and the rotor 3, here the permanent magnets 10 (not visible in the figures), to prevent the stationary and rotating parts from touching. Heat dissipation through this air gap is difficult, and alternative heat dissipation paths must be created.

[0050] External ribs 29 are attached to the body of the rotor 3, which nevertheless promote heat dissipation via the rotor 3.

[0051] An important heat dissipation path runs via heat conduction through the stator bushing 20, which is advantageously made of highly thermally conductive aluminum, namely via the stator tower 21 and the stator flange 16 to a cooling system located in a radial outer area of ​​the stator flange 16, consisting in particular of the heat-emitting cooling elements or cooling fins 17. There the heat can be released to the environment (especially ambient air).

[0052] In the exemplary embodiment, the outer cooling fan wheel 15, which is attached to the rotor flange 23 and causes air movements and turbulences during operation of the electric machine 1, helps to dissipate heat from the cooling elements 17 at the stator flange 16 of the stator 2.

[0053] The stator bushing 20, consisting in particular of stator tower 21 and stator flange 16, therefore primarily has both a supporting function and a heat dissipation function from waste heat generated inside the electromagnetic system of the stator 2.

[0054] It has been shown that, particularly in large electric machines 1, for example with an air gap diameter of more than 150 mm or 200 mm, heat dissipation to the outside becomes increasingly difficult, especially since such machines sometimes operate at rather low speeds (e.g. 500-1500 rpm), particularly when large turbocharged turbomachines are used. According to the invention, internal cooling channels 4 are provided for significantly improved heat dissipation. These channels run within the stator bushing 20 and allow a fluid to flow through them, which carries away heat convectively, i.e., by means of moving flow.

[0055] Liquid and gaseous substances are suitable as fluids.

[0056] If components of a system are operated in which cooling fluids are used, it is advantageous to circulate such cooling fluids through the cooling channels 4. A cooling fluid channel can be connected to a suitable interface on the stator 2.

[0057] If turbomachines are operated in a gaseous fluid, in particular fans with air, the cooling channels 4 (or the cooling channel, if applicable) can be permeated with this fluid, as in the exemplary embodiment, in order to transfer the waste heat to this medium.

[0058] Pressure differences or flow velocities generated by the turbomachine or the fan itself can be used to passively convey the cooling medium through the cooling channels 4.

[0059] In the exemplary embodiment, the internal cooling channels 4 run approximately parallel to the axis through the stator tower 21 of the stator bushing 20 of the stator 2, specifically between the inner wall 36 of the stator tower 21 and the outer wall 39. Thus, the waste heat is absorbed and transported away directly near the stator lamination stacks 8 by the cooling medium in the cooling channels 4.

[0060] The thermally critical bearings 12,13 are thereby protected from excessive temperature exposure, since the cooling channels 4 or the cooling medium flowing in them transport the heat away in the heat conduction path in front of the bearings 12, 13.

[0061] The stator bushing 20 can advantageously be manufactured in one piece using aluminum die casting. The axial alignment of the internal cooling channels 4 allows for demolding. If necessary, the diameters of the cooling channels 4 must be selected to be sufficiently large to facilitate demolding. A draft angle is typically applied along the cooling channels 4. This allows for a larger radial installation space occupied by the stator tower 21.

[0062] In the die-casting process, the cooling channels 4 can also contribute to process cooling, as the aluminum can be cooled during the manufacturing process. This allows for the production of a more stable and resistant stator tower 21 overall, whereas previously, without cooling channels 4, the maximum wall thickness of the stator tower 21 was the limiting factor. Therefore, the design of the cooling channels 4, when used for process cooling in the casting process, can also be of considerable advantage for the strength design of the stator bushing 20.

[0063] For the realization of more delicate cooling channels 4, salt cores can also be used in the aluminium casting process, for example.

[0064] It is also quite conceivable to introduce round cooling channels into a cast stator bushing by machining, in particular by drilling.

[0065] The external rotor motor in the embodiment shown in Fig. 1-7 is particularly suitable for use with fans. A pressure difference already generated by the fans in the higher-level air handling system ensures that the internal cooling channels 4 are advantageously traversed from the side of the electronics housing 18, which has a flow passage 6 formed inside for this purpose, centrally passing the axial height of the stator flange 16 through the stator tower 21, thereby absorbing waste heat and dissipating it towards the rotor 3 and through designated openings 7.

[0066] To ensure a high degree of protection, in the exemplary embodiment the cooling flow through the cooling channels 4 is separated from the electromagnetic system by the seal 24. For this purpose, the flow separation 14 is also provided on the rotor 3 (Figs. 4, 4a).

[0067] In this embodiment, control electronics are integrated into the external rotor motor 1. This also generates waste heat, particularly at the power components 22, such as an input stage or an output stage. The electronics housing 18 serves as a receiving area for the control electronics. It also has external heat-dissipating cooling fins 26.

[0068] The electronic pot 18 can be integrated as a single unit into the stator socket 20 or be a separate component.

[0069] In the exemplary embodiment, the electronic housing 18 also has external cooling channels 25, advantageously particularly in the area of ​​high-heat-generating power components 22. The advantageous heat dissipation by the cooling medium in the internal cooling channels 4 towards the rotor 3 through the openings 7 into the environment significantly reduces the additional heat load on the electronic housing 18, which inevitably occurs via heat conduction in the stator flange 16. Thus, the internal cooling channels 4 provide substantial thermal relief to the components in the electronic housing 18.

[0070] A simulation demonstrated a significant thermal reduction in a 12 kW motor with an air gap diameter of 200 mm and a speed of 1000 rpm. The external pressure differential for operating the cooling channels 4 was 150 Pa. The power components 22 were relieved of over 30 K, and the stator winding 9 and rotor-side bearing 13 by over 25 K. Depending on the design, even higher reductions can be achieved; this was a preliminary design.

[0071] If no or insufficient external pressure difference is expected and cooling with the ambient medium is still desired, an additional internal cooling fan wheel can be attached to the shaft in the flow passage area 6, for example, which actively pumps cooling medium through the cooling channels 4.

[0072] It is also conceivable to connect an external cooling air supply to the electric machine 1, which conveys external cooling medium through the internal cooling system with the internal cooling channels 4. For this purpose, appropriate interfaces may be provided on an electric external rotor machine.

[0073] Fig. 8 and, in a detailed view of the area near the axis, Fig. 8a, show, in perspective view from the stator side and in a section in a plane through the axis, a modified embodiment of a rotating external rotor electric machine 1 with internal cooling channels 4. In contrast to the embodiment according to Figs. 1-7, the stator tower 21 is thickened overall, i.e., the thickness between the inner wall 36 and the outer wall 39 of the stator tower 21 is greater. This gives the stator tower 21, and in particular the transition to the stator flange 16, additional stability.

[0074] In particular, the cooling channels 4 can also have larger diameters, which simplifies their manufacture. In the exemplary embodiment, inserted tubes 42, advantageously aluminum or copper tubes, here by way of example with a diameter of 8 mm and a wall thickness of 1 mm, are cast in. These inserted tubes 42 are easy to hold and guide during the casting process.

[0075] In order to improve the flow of cooling medium and thus the cooling effect of the internal cooling system with the internal cooling channels 4 at a given external pressure difference, an inflow optimizer 41 is provided, which gives each cooling channel 4 an assigned, flow-optimized inflow area 31, analogous to an inflow nozzle from air technology, in particular to reduce inflow losses.

[0076] In the exemplary embodiment, the inflow optimizer 41 is designed as a plastic component, which can advantageously also be used to cover the stator-side bearing 12.

[0077] The stator-side bearing 12 and the rotor-side bearing 13 can be sealed from the environment, if required, by suitable sealing elements, such as shaft seals. This prevents the ingress of dust, moisture, or other contaminants into the bearing area, which is particularly advantageous in applications requiring a higher degree of protection.

[0078] In embodiments with a thicker stator tower 21, this naturally occupies more radial space. The electromagnetic system of the stator 2 may need to be adapted because its inner diameter must be slightly increased.

[0079] Fig. 9 and, in a detailed view of the area near the axis, Fig. 9a, show, in perspective view from the stator side and in a section in a plane through the axis, a modified and particularly advantageous embodiment of a rotating electric machine 1 in external rotor design with internal cooling channels 4. In contrast to the embodiments according to Figs. 1-7 and Fig. 8, the stator tower 21 is no longer manufactured by aluminum die casting, but as a separate component by extrusion, as an extruded part 43. The remaining part of the stator bushing 20, in particular with stator flange 16, external cooling elements 17, external screw-on devices 27 and also a connection area 33 for connecting the stator flange 16 to the stator tower 21, is advantageously manufactured by aluminum die casting.

[0080] Advantageously, the extruded stator tower 21 is shrunk into a corresponding receptacle on the cast stator flange 16 in the connection area 33, which has been advantageously turned or honed to a precise diameter.

[0081] It can also be glued, welded, soldered, or similar methods.

[0082] By extruding the stator tower 21 as an extruded part 43, comparatively delicate cooling channels 4 can be formed. The stator tower 21 can be manufactured cost-effectively, with material efficiency, and with high dimensional accuracy.

[0083] For different lengths of the electric machine 1, the stator tower 21 can simply be cut to length from meter-long material to match the extruded part 43 used.

[0084] In the exemplary embodiment, the bearing seats 35, 30 in the extruded stator tower 21 are re-machined in the area of ​​its inner wall 36.

[0085] In the exemplary embodiment, the stator tower 21 also extends axially through the area of ​​the electronics housing 18. This allows for a large axial bearing distance.

[0086] The connection area between the cast stator flange 16 and the extruded stator tower 21 runs within the electronics housing 18, axially opposite the electromagnetic system. This provides radial installation space for the electromagnetic system, allowing it, and in particular its stator lamination stack 8, to be mounted directly onto the extruded stator tower 21. It is conceivable that longitudinal grooves or similar features are provided in the extruded stator tower 21 to ensure that the stator stack 8 can be mounted in a rotationally secure manner.

[0087] Reference symbol list

Claims

Claims 1. Rotating electric machine in external rotor design, in particular an electric external rotor motor or generator, especially for turbomachinery, in particular for fans or wind turbines, but also for electromobility, with a rotor with a shaft which is supported inside a stator tower of the stator or the stator bushing, characterized in that in the stator bushing, in particular in the stator tower, between an inner wall of the stator tower, which can be associated with the bearing housing and which is opposite the rotor shaft, and an outer wall of the stator tower, to which the electromagnetic system, consisting in particular of the stator core and stator windings, is attached, one or more cooling channels are formed in which a fluid flowing relative to the stator bushing absorbs and carries away waste heat from the machine and in particular from the electromagnetic system.

2. Rotating electric machine according to claim 1, characterized in that several cooling channels are distributed approximately symmetrically around the circumference in the stator tower and run approximately parallel to the axis, passing in the vicinity of the laminated cores.

3. Rotating electric machine according to claim 1 or 2, characterized in that the cooling channels are permeated by an ambient medium, in particular air, which flows into the internal cooling system, consisting in particular of the internal cooling channels and associated inlet and outlet areas, at a provided inlet and outlet and flows back into the environment at a provided outlet.

4. Rotating electric machine according to claim 1 or 2, characterized in that the cooling channels are supplied with a cooling fluid.

5. Rotating electric machine according to one of claims 1 to 4, characterized in that the stator bushing, in particular with stator flange and stator tower, is manufactured in one piece in die casting, advantageously in aluminium.

6. Rotating electric machine according to claim 5, characterized in that the cooling channels are machined after the casting process.

7. Rotating electric machine according to claim 5, characterized in that the cooling channels are formed by inlays, for example tubes, cast in during the casting process.

8. Rotating electric machine according to claim 5, characterized in that the cooling channels in the casting process are formed by salt cores or similar materials.

9. Rotating electric machine according to one of claims 1 to 4, characterized in that the stator tower is manufactured entirely or at least substantially entirely in one piece by extrusion and is joined with a cast component comprising substantially the stator flange.

10. Rotating electric machine according to claim 9, characterized in that the extruded stator tower is shrunk, pressed, glued, welded or soldered into an advantageously turned or honed recess in the stator flange.

11. Rotating electric machine according to one of claims 1 to 10 for operating a turbo-turbine machine with an impeller, wherein, as a result of the rotation of the impeller, a pressure difference or flow velocity is created which causes or promotes a flow through the internal cooling system with the internal cooling channels.

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