Abstract
An electrical machine for integration into a vehicle frame structure is provided. The vehicle frame structure includes a structural wall that at least partially encloses an inner volume. The electrical machine includes a rotor with a rotor shaft. The rotor shaft is rotatable around a rotational axis, and is connectable to a propulsor for transferring torque to or from a fluid. The electrical machine includes a first bearing unit configured to hold the rotor shaft in a rotatable manner and a second bearing unit configured to hold the rotor shaft in a rotatable manner. The first bearing unit is releasably attachable to a first wall region of the structural wall, and the second bearing unit is releasably attachable to a second wall region of the structural wall. The first wall region and the second wall region are spaced apart with respect to the rotational axis.
Claims
1. An electrical machine for integration into a vehicle frame structure, wherein the vehicle frame structure comprises a structural wall that at least partially encloses an inner volume, the electrical machine comprising: a rotor with a rotor shaft, wherein the rotor shaft is rotatable around a rotational axis and connectable to a propulsor for transferring torque to or from a fluid; a first bearing unit configured to hold the rotor shaft in a rotatable manner; and a second bearing unit configured to hold the rotor shaft in a rotatable manner, wherein the first bearing unit is releasably attachable to a first wall region of the structural wall, and the second bearing unit is releasably attachable to a second wall region of the structural wall, and wherein the first wall region and the second wall region are spaced apart with respect to the rotational axis.
2. The electrical machine of claim 1, wherein the propulsor is a propeller.
3. The electrical machine of claim 1, wherein the rotor is connected in a torque transferring manner to the rotor shaft via a flexible coupling.
4. The electrical machine of claim 1, further comprising: a cooling system for guiding a cooling fluid flow, the cooling system comprising at least one fluid inlet and at least one fluid outlet, wherein the at least one fluid inlet and the at least one fluid outlet are arranged in or on the structural wall.
5. The electrical machine of claim 4, wherein the at least one fluid outlet comprises a suction outlet, the suction outlet being configured to propel the cooling fluid flow.
6. The electrical machine of claim 5, wherein the suction outlet is configured to propel the cooling fluid flow by an ambient fluid flow flowing relative to the electrical machine, the vehicle frame structure, or the electrical machine and the vehicle frame structure.
7. The electrical machine of claim 1, wherein the first bearing unit, the second bearing unit, or the first bearing unit and the second bearing unit are releasably attachable to the structural wall by an adapter plate, and the first bearing unit, the second bearing unit, or the first bearing unit and the second bearing unit are fixed to the adapter plate.
8. The electrical machine of claim 7, wherein the adapter plate is configured to cover a wall opening with an opening diameter, and wherein the opening diameter is larger than an outer machine diameter of the electrical machine.
9. The electrical machine of claim 7, wherein the adapter plate comprises a shoulder configured to fit to a wall shoulder of the structural wall.
10. The electrical machine of claim 7, further comprising: a stator module that is attachable to the structural wall or to the adapter plate.
11. The electrical machine of claim 10, further comprising a cartridge that contains the rotor, the stator module, the first bearing unit, the second bearing unit, or any combination thereof, and wherein the cartridge is attachable to the structural wall, to the adapter plate, or to the structural wall and to the adapter plate.
12. The electrical machine of claim 11, wherein the cartridge comprises a plurality of cartridge orifices, is a framework cartridge, or a combination thereof.
13. The electrical machine of claim 11, further comprising a machine fairing, wherein the machine fairing at least partially surrounds the electrical machine, the cartridge, or the electrical machine and the cartridge.
14. An electrical propulsion unit comprising: an electrical machine for integration into a vehicle frame structure, wherein the vehicle frame structure comprises a structural wall that at least partially encloses an inner volume, the electrical machine comprising: a rotor with a rotor shaft, wherein the rotor shaft is rotatable around a rotational axis and connectable to a propulsor for transferring torque to or from a fluid; a first bearing unit configured to hold the rotor shaft in a rotatable manner; and a second bearing unit configured to hold the rotor shaft in a rotatable manner, wherein the first bearing unit is releasably attachable to a first wall region of the structural wall, and the second bearing unit is releasably attachable to a second wall region of the structural wall, and wherein the first wall region and the second wall region are spaced apart with respect to the rotational axis.
15. The electrical propulsion unit of claim 14, further comprising: a power converter that is electrically connected to an energy supply via at least one supply cable, is mounted to the structural wall, or is electrically connected to the energy supply via the at least one supply cable and is mounted to the structural wall.
16. A vehicle frame structure for an aircraft, the vehicle frame structure comprising: a structural wall that at least partially encloses an inner volume; and an electrical machine comprising: a rotor with a rotor shaft, wherein the rotor shaft is rotatable around a rotational axis and connectable to a propulsor for transferring torque to or from a fluid; a first bearing unit configured to hold the rotor shaft in a rotatable manner; and a second bearing unit configured to hold the rotor shaft in a rotatable manner, wherein the first bearing unit is releasably attachable to a first wall region of the structural wall, and the second bearing unit is releasably attachable to a second wall region of the structural wall, and wherein the first wall region and the second wall region are spaced apart with respect to the rotational axis.
17. The vehicle frame structure of claim 16, wherein the vehicle frame structure is or comprises a rotor boom.
18. The vehicle frame structure of claim 16, wherein the structural wall comprises at least one wall opening configured to accommodate an adapter plate, a cartridge, or the adapter plate and the cartridge.
19. The vehicle frame structure of claim 16, further comprising: a fork structure configured to receive the electrical machine.
20. A vehicle comprising: a vehicle frame structure comprising: a structural wall that at least partially encloses an inner volume; and an electrical machine comprising: a rotor with a rotor shaft, wherein the rotor shaft is rotatable around a rotational axis and connectable to a propulsor for transferring torque to or from a fluid; a first bearing unit configured to hold the rotor shaft in a rotatable manner; and a second bearing unit configured to hold the rotor shaft in a rotatable manner, wherein the first bearing unit is releasably attachable to a first wall region of the structural wall, and the second bearing unit is releasably attachable to a second wall region of the structural wall, and wherein the first wall region and the second wall region are spaced apart with respect to the rotational axis.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] Further advantages, features, and details of the invention result from the following description of the embodiments, as well as from the drawings.
[0052] FIG. 1 shows a first embodiment of an electrical propulsion unit with an electrical machine according to the disclosure in a front view cross sectional illustration;
[0053] FIG. 2 is a side view cross sectional illustration of the first embodiment;
[0054] FIG. 3 is a top view illustration of the first embodiment;
[0055] FIG. 4 is a second embodiment of an electrical propulsion unit according to the disclosure in a side view cross sectional illustration;
[0056] FIG. 5 is a third embodiment of an electrical propulsion unit according to the disclosure in a side view cross sectional illustration;
[0057] FIG. 6 is a fourth embodiment of an electrical propulsion unit according to the disclosure in a side view cross sectional illustration;
[0058] FIG. 7 is a fifth embodiment of an electrical propulsion unit according to the disclosure in a front view cross sectional illustration;
[0059] FIG. 8 is a side view cross sectional illustration of the fifth embodiment;
[0060] FIG. 9 is a top view illustration of the fifth embodiment;
[0061] FIG. 10 is a first example of an adapter plate and a structural wall in a schematic, cross sectional illustration;
[0062] FIG. 11 shows a second example of an adapter plate and a structural wall in a schematic, cross sectional illustration;
[0063] FIG. 12 shows a third example of an adapter plate and a structural wall in a schematic, cross sectional illustration;
[0064] FIG. 13 shows a sixth embodiment of an electrical propulsion unit according to the disclosure in a front view cross sectional illustration;
[0065] FIG. 14 shows a seventh embodiment of an electrical propulsion unit according to the disclosure in a front view cross sectional illustration;
[0066] FIG. 15 shows an eighth embodiment of an electrical propulsion unit according to the disclosure in a front view cross sectional illustration;
[0067] FIG. 16 shows a ninth embodiment of an electrical propulsion unit according to the disclosure in a front view cross sectional illustration;
[0068] FIG. 17A shows a tenth embodiment of an electrical propulsion unit according to the disclosure in a top view illustration in a first mounting state;
[0069] FIG. 17B shows the tenth embodiment in a second mounting state;
[0070] FIG. 18 shows an eleventh embodiment of an electrical propulsion unit according to the disclosure in a top view illustration; and
[0071] FIGS. 19A and 19B show schematic illustrations of a vehicle in form of an aircraft with electrical propulsions units according to the disclosure.
DETAILED DESCRIPTION
[0072] FIG. 1 shows a first embodiment 300A of an electrical propulsion unit 300 according to the disclosure. The electrical propulsion unit 300 includes an electrical machine 100 configured as a transversal flux machine 102. Any other type of electrical machine, such as a radial flux machine or axial flux machine, may alternatively be applied within the scope of this disclosure.
[0073] In the embodiment shown, the electrical machine 100 is integrated into a vehicle frame structure 1000 in the form of an airframe 1010 of an aircraft 1002 (not shown here). The airframe 1010 includes a rotor boom 1180, the cross-section of which is visible in FIG. 1. A surface of the rotor boom 1180 may hold the electrical propulsion unit 300, including propulsor 302, in a fixed position with respect to the airframe 1010. The aircraft 1002, and the airframe 1010 respectively, comprises a plurality of (e.g., eight) propulsors 302 that are arranged on a plurality of rotor booms 1180 (not shown in FIG. 1).
[0074] The electrical machine 100 includes a stator module 180 with windings (not shown here). The electrical machine 100 includes a rotor 110 that, in the case shown in FIG. 1, is configured as an out-runner rotor, arranged on a radial outer side of the stator module 180. Any other type of arrangement of the rotor with respect to the stator, such as an in-runner rotor arrangement, may alternatively be applied within the scope of this disclosure.
[0075] The rotor 110 is fixed to a rotor shaft 120 via a flexible coupling 240. Due to a fixed connection between the rotor 110 and rotor shaft 120 (e.g., via the flexible coupling 240), the rotor 110 and the rotor shaft 120 rotate together around a rotational axis AR. The electrical machine 100 includes a first bearing unit 140 that is attached to a structural wall 1100 in a first wall region 1012 of the structural wall 1100, and a second bearing unit 160 that is attached to the structural wall 1100 in a second wall region 1014 of the structural wall 1100. The rotational axis AR lies within the drawing plane of FIG. 1.
[0076] The first wall region 1012 and the second wall region 1014 are arranged substantially parallel to each other and on opposing sides of the rotor boom 1180. The first wall region 1012 is located on a propulsor facing side 1322 of the structural wall 1100. The second wall region 1014 is located on a propulsor averted side 1324 of the structural wall 1100. As visible in FIG. 1, the rotor boom 1180 includes a closed cross section, with the structural wall 1100 enclosing an inner volume 1120.
[0077] The rotor shaft 120 is connected to a propulsor 302 (e.g., in the form of a propeller 304) configured to transfer torque to surrounding air (e.g., to generate thrust to propel and/or lift the aircraft 1002). For this purpose, the rotor shaft 120 extends out of the structural wall 1100 of the rotor boom 1180 at the first wall region 1012.
[0078] The first bearing unit 140 and the second bearing unit 160 are fixed to the structural wall 1100 via adapter plates 200. The first bearing unit 140, arranged on the first wall region 1012 facing the propulsor 302, is fixed to the structural wall 1100 via a first adapter plate 202. The second bearing unit 160, arranged on the second wall region 1014, is fixed to the structural wall 1100 via a second adapter plate 204.
[0079] The first adapter plate 202 is configured as an open adapter plate including a through hole, through which the rotor shaft 120 extends from the inner volume 1120 to the outside. The second adapter plate 204 is a closed adapter plate, at which the rotor shaft 120 terminates.
[0080] Optionally, as indicated in FIG. 1, the vehicle frame structure 1000 may include a wall surface layer 1140 arranged on the structural wall 1100. The wall surface layer 1140 may include a containment layer 1142, and/or a noise shield layer 1144, and/or an EMI shield layer 1146.
[0081] The adapter plates 200 establish a mechanical connection between the structural wall 1100 and the corresponding bearing unit 140, 160. An adapter plate 200 allows for better replaceability of the bearing units 140, 160 and thus for better maintenance and repair of the electrical machine 100. The adapter plates 200 further improve the distribution of forces from the bearing units 140, 160 into the structural wall 1100, and thus the vehicle frame structure 1000. Whereas the illustration of FIG. 1 shows a cross-sectional view of the electrical
[0082] propulsion unit 300A in a plane perpendicular to a boom axis AB of the rotor boom 1180, the illustration of FIG. 2 is a cross-sectional view parallel to the boom axis AB.
[0083] Optionally, the electrical propulsion unit 300 may include a cooling system 250, as shown here. In FIG. 2, a cooling system 250 is schematically illustrated, which is configured to cool the electrical propulsion unit 300 (e.g., the electrical machine 100). The cooling system 250 is configured to form and/or guide a cooling fluid flow 280 to the rotor 110 and/or the stator module 180 in order to extract heat out of these components and accordingly cool the components. Optionally, the cooling system 250 may include one or more cooling fluid conduits 252 for guiding the cooling fluid flow 280, one of which is shown as an example in FIG. 2. In other embodiments, such cooling fluid conduits 252 may not be necessary, as the inner volume 1120 of the vehicle frame structure 1000 provides sufficient guiding. In the embodiment shown, the cooling fluid flow 280 is a cooling air flow. The cooling system 250 includes a fluid inlet 260 that is arranged on the propulsor facing side 1322 of the structural wall 1100. Further, the fluid inlet 260 is arranged in a radially outer region of the propulsor 302, allowing to draw in air that has been accelerated by the propulsor 302 to a relatively high speed and/or pressure. By such arrangement, a relatively high mass flow of the cooling fluid flow 280, and thus a required cooling performance, may be achieved. Alternatively or additionally, the fluid inlet 260 may be arranged in a different part of the structural wall 1100 (e.g., on the propulsor facing side 1322, such as an optional, further fluid inlet 260 shown in FIG. 2). A fluid inlet 260 enables the cooling fluid flow 280 to enter the inner volume 1120, to contact the components of the electrical machine 100 for extracting heat.
[0084] The cooling system 250 may further include one or more fluid outlets 270, such as a first fluid outlet 270.1 and a second fluid outlet 270.2 shown here. The cooling system 250 may include conduits for guiding the cooling fluid flow 280. The conduits are not shown here for the sake of clarity.
[0085] The electrical propulsion unit 300 further includes a power converter 350 that is electrically connected to the electrical machine 100 (e.g., to the stator module 180). The power converter 350 is configured to supply AC current to the electrical machine 100 when operated in a motor mode, and/or optionally receive AC current from the electrical machine 100 when operated in a generator mode. The power converter 350 is connected to an energy supply 370 via a supply cable 360. The supply cable 360 may include a first supply conductor 360.1 and the second supply conductor 360.2, as shown here. Optionally, as indicated here, the power converter 350 and/or the supply cable 360 may be arranged such that the power converter 350 and/or the supply cable 360 is exposed to the cooling fluid flow 280 or, as shown here, to a secondary cooling fluid flow 282 branched off from the cooling fluid flow 280 (e.g., by a manifold or the like flow guiding means (not shown here)).
[0086] FIG. 3 shows the electrical propulsion unit 300A of FIG. 1 and FIG. 2 from a top view. As shown, the rotor boom 1180 extends along the boom axis AB with a substantially constant cross-section, where the cross section widens at the end of the rotor boom 1180 in order to accommodate the electrical propulsion unit 300 (e.g., the electrical machine 100).
[0087] The rotor boom 1180 may, in addition to its structural wall 1100, include a support structure 1200 (e.g., to reinforce the rotor boom 1180). This may be advantageous, as high forces act on the rotor boom 1180 during operation. A beam belt 1210 may be fixed to the structural wall 1100, may be arranged in the inner volume 1120, and may extend, for example, along the boom axis. By arranging the bearing units near or on the support structure 1200 (e.g., the beam belt 1210), the mechanical properties of the electrical machine 100 may be improved. For example, the stiffness may be improved, resulting in reduced misalignment of the rotor shaft 120 and/or reduced bearing tolerances of the bearing units 140, 160.
[0088] FIG. 4 shows a further embodiment 300B of an electrical propulsion unit 300 with a further cooling system 250B. The embodiment shown differs from the previous embodiment in that the cooling system includes two fluid inlets 260 (e.g., a first fluid inlet 260.1 and a second fluid inlet 260.2) that are arranged on the side of the structural wall 1100 facing the propulsor 302 (e.g., a propulsor facing side 1322). The cooling system 250B further includes two fluid outlets 270 (e.g., a first fluid outlet 270.1 and a second fluid outlet 270.2) arranged on an opposing side 1324 of the structural wall 1100, averted from the propulsor 302.
[0089] For example, the fluid inlets 260.1, 260.2 are arranged in proximity of the first wall region 1012 of the structural wall 1100 (e.g., above the electrical machine 100), and the fluid outlets 270.1, 270.2 are arranged in proximity of the second wall region 1014 of the structural wall 1100 (e.g., below the electrical machine 100). With such arrangement, a substantially straight cooling fluid flow 280 (e.g., substantially parallel to the rotational axis AR) may be achieved. As the fluid inlets 260.1, 260.2 and/or the fluid outlets 270.1, 270.2 are arranged within the area of the electrical machine 100, a deflection of the cooling fluid flow 280 may be reduced or minimized.
[0090] FIG. 5 shows another embodiment 300C of an electrical propulsion unit 300 according to the present embodiments. The electrical propulsion unit 300 C differs from the previous electrical propulsion units 300A, 300B in that the electrical propulsion unit 300 includes another cooling system 250C. The cooling system 250C includes a suction outlet 272 configured to propel the cooling fluid flow 280. For example, the suction outlet 272 is arranged at a position with a relatively high under pressure and/or at a position subjected to an ambient airflow 284. The ambient airflow 284 may be adapted to drag the cooling airflow 280, thus accelerating the cooling airflow 280 upon exiting at the suction outlet 272. Thus, in the embodiment shown, the basic principle for propelling the cooling fluid flow 280 is mainly based on suction (e.g., a relative negative pressure) rather than compression. The cooling system 250C further includes a first fluid inlet 260.1 and a second fluid inlet 260.2, arranged on the opposing side 1324 of the structural wall 1100, averted from the propulsor 302.
[0091] FIG. 6 shows yet another embodiment 300D of an electrical propulsion unit 300. The electrical propulsion unit 300D includes yet another cooling system 250D. The cooling system 250D includes, similar to the previous cooling system 250C, a suction outlet 272. As a difference to the cooling system 250C shown in FIG. 5, however, the fluid inlets 260.1, 260.2 are arranged on a propulsor facing side 1322 of the vehicle frame structure 1000. Via such arrangement, the suction based propelling principle of the cooling fluid flow 280 may be combined with a pressure based propelling principle, as the fluid inlets 260.1, 260.2 are arranged in proximity of the propulsor 302 and thus of the airflow propelled by the propulsor 302.
[0092] FIG. 7, FIG. 8, and FIG. 9 show yet another embodiment 300E of an electrical propulsion unit 300. As a difference to the previously shown embodiments, the electrical propulsion unit 300 includes a cartridge 320. The cartridge 320 is configured to accommodate main components of the electrical machine 100E (e.g., the rotor 110, the stator module 180, as well as the first bearing unit 140 and the second bearing unit 160. Using a cartridge 320, the repair and/or replacement of an electrical machine 100E may be facilitated, as the relevant components of the electrical machine 100E are contained within the cartridge 320. In other words, the cartridge 320 may be considered a replaceable module of an electrical machine 100. The cartridge 320 includes and/or is attachable to adapter plates 200, such as, for example, a first adapter plate 102 and a second adapter plate 204. The adapter plates 200, 202, 204 constitute the mechanical interfaces of the electrical machine 100 to the vehicle frame structure 1000 (e.g., the structural wall 1100). According to the present embodiments, the electrical propulsion unit 300E gains structural support from the attachment to the structural wall 1100 via the adapter plates 200.
[0093] Turning to FIG. 8, the electrical propulsion unit 300 comprises an opening adapter plate 208 that is configured to fit into a wall opening 1020 of the structural wall 1100. Using such an opening adapter plate 208, the cartridge 320 may be inserted into, and ejected from, the vehicle frame structure 1000 (e.g., as a whole). The opening adapter plate 208 has a circular shape with a plate diameter RP that corresponds to an opening diameter RO of the wall opening 1020. For example, the opening diameter RO is equal to or larger than an outer cartridge diameter RC of the cartridge 320 to allow the cartridge 322 pass the wall opening 1020.
[0094] The plate diameter RP may differ from the opening diameter RO (e.g., may be larger) in order to form a shoulder 210 of the adapter plate 200 (e.g., of the opening adapter plate 208).
[0095] FIG. 10, FIG. 11, and FIG. 12 show embodiments with different ways of fixing a bearing unit 140, 160 to a structural wall 1100, within the scope of this disclosure. The embodiments and, for example, adapter plates 200 shown in FIGS. 10-12, or variations or combinations thereof, may be applied to any embodiment of electrical machines 100 shown in this disclosure.
[0096] FIG. 10 shows a first adapter plate 200A configured as a flange adapter plate 212. The flange adapter plate 112 includes a main portion 222 and a flange portion 224 extending radially, so as to form a shoulder 210. The bearing unit 140 is arranged in a bearing seat 144 and is axially fixed via a retaining ring 146.
[0097] The wall opening 1020 is configured such that a wall shoulder 1116 is formed. The wall shoulder 1116 protrudes radially inward and forms a surface to mate with the shoulder 210 of the adapter plate 200. The adapter plate 200 may be fixed with a plurality of bolts 214, two of which are shown here as an example. Via a flange-like connection of the adapter plate 200 and the structural wall 1100, a stable, yet compact mechanical connection may be achieved. For example, the adapter plate is fixed flush within the structural wall 1100, allowing for improved outer fluid dynamic properties of the vehicle frame structure 1000. In the embodiment shown, a rotor shaft 120 of an electrical machine reaches from an inner volume 1120 of the vehicle frame structure 1000 through the structural wall 1100 to the outside of the vehicle frame structure 1000 and connects to a propulsor (not shown here). Such arrangement is particularly suitable when the adapter plate 200 and/or the bearing unit 140 is arranged on a propulsor facing side 1322 of the vehicle frame structure 1000.
[0098] FIG. 11 shows another adapter plate 200B. As a difference to the previously shown embodiment of FIG. 10, the adapter plate 200B does not feature a through hole for accommodating the rotor shaft 120. In contrast, the rotor shaft 120 terminates at the bearing unit 160. As a further difference, the adapter plate 200 is mounted on top of the structural wall 1100 (e.g., not mounted flush within the structural wall 1100) using bolts 214. Such mounting allows for a relatively simple design (e.g., since no tolerances or shoulders have to be fitted together). Such mounting as shown in FIG. 11 is particularly suitable for an arrangement in the inner volume 1120 of the vehicle frame structure 1000, where aerodynamic considerations are of reduced relevance or negligible. Such arrangement is particularly suitable when the adapter plate 200 and/or the bearing unit 160 is arranged on a propulsor averted side 1324 of the vehicle frame structure 1000.
[0099] FIG. 12 shows yet another adapter plate 200C that may particularly be arranged on a propulsor averted side 3024 of the structural wall 1100. Similarly to the adapter plate shown in FIG. 10, the adapter plate 200C includes a flange portion 224, and the adapter plate 200 sits flush in the structural wall 1100. As a difference to FIG. 10, the rotor shaft 120 terminates at the adapter plate 200C, and thus, the adapter plate 200C provides an axial stop for the rotor shaft 120. The shown arrangement is particularly suitable for mounting a second bearing unit 160 on a propulsor averted side 1024 that is easily accessible and replaceable.
[0100] Also, combinations of the features of different shown adapter plates, as well as variations (e.g., regarding flange type, through hole, and/or flush arrangement) may be realized in the scope of this disclosure.
[0101] FIG. 13 shows another embodiment of an electrical propulsion unit 300F. As a difference to the previously shown embodiments, the electrical propulsion unit 300F includes an electrical machine 100F that is configured as a radial flux machine with an in-runner rotor 110F. It should be obvious to the person skilled in the art, that an electrical machine 100 and/or an electrical propulsion unit 300 according to the present disclosure may be of any other type (e.g., including electrical machines with axial flux, radial flux, and/or transfers the flux as well as radial and/or axial air gaps).
[0102] FIG. 14 shows another embodiment of an electrical propulsion unit 300G. As a difference to the electrical propulsion unit 300E shown in FIGS. 7-9, the cartridge 320 of the electrical machine 100G is a framework cartridge 322. The framework cartridge 322 includes a plurality of longitudinal body elements that are joined together, forming a plurality of cartridge orifices 328 formed therebetween, two of which are indicated exemplarily in FIG. 14. In the present embodiment, the framework cartridge 322 includes a tubular structure 324. The tubular structure 324 includes a plurality of tubes 326, two of which are exemplarily indicated in FIG. 14. Using a framework cartridge 322, weight may be saved while achieving a required degree of stiffness (e.g., in an axial direction). Further, the cooling of the electrical machine 100 may be facilitated by a framework cartridge 322, as a cooling fluid flow may pass from elsewhere in the inner volume 1120 to the electrical machine 100.
[0103] FIG. 15 illustrates possible bearing units 140, 160 applicable in an electrical machine 100H of a further electrical propulsion unit 300H according to the present disclosure. A first bearing unit 140 includes a floating bearing 172 (e.g., in the form of a roller bearing 174 with a plurality of cylindrical roller elements). Such floating bearing 172 allows for an axial tolerance (e.g., of an axial extension of the rotor shaft 120, such as due to thermal expansion during operation). The floating bearing 172 includes an outer bearing shell fixed to the first adapter plate 202.
[0104] The electrical machine 100H includes a second bearing unit 160 that again includes a fixed bearing 176 in the form of a ball bearing 178. The ball bearing 178 includes a plurality of spherical roller elements that are configured to be rotatably engaged with an inner bearing shell and an outer bearing shell, thus enabling a rotational movement around the rotational axis AR, while providing an axial fixation of the rotor shaft 120. The outer bearing shell of the fixed bearing 176 is fixed to the second adapter plate 204.
[0105] The electrical machine 100H may optionally include a cartridge 320 that is fixed to the first adapter plate 202 and the second adapter plate 204. With such a cartridge 320, a further alignment (e.g., axial alignment) of the first bearing unit 140 and the second bearing unit 160 may be achieved. For that purpose, the cartridge 320 may have an axial stiffness (e.g., a stiffness in a direction of the rotational axis AR) that is significantly higher than the stiffness of the vehicle frame 1000 in a direction of the rotational axis AR.
[0106] FIG. 16 illustrates yet another embodiment of an electrical machine 100J. As a difference to the previously shown electrical machine 100H, the electrical machine 100J includes a first bearing unit 140 with a further fixed bearing 176, here in the form of a further ball bearing 178. Hence, the first bearing unit 140 includes a first part 140.1 with a floating bearing 172 in the form of a roller bearing 174, and a second part 140.2 with a further fixed bearing 176 the form of the further ball bearing 178. Optionally, the adapter plate 200 holding the further fixed bearing 176 may include an elastic element 216, such as an annular plastic insert, and/or a plurality of circumferentially arranged orifices. Using such an elastic element 216, a flexibility of the adapter plate 200 in the axial direction may be increased, and axial loads (e.g., due to thermal growth during operation of the electrical machine) may be reduced.
[0107] FIG. 17A and FIG. 17B illustrate another embodiment of an electrical machine 100K, and a vehicle frame structure 1000K in the form of a rotor boom 1180. The vehicle frame structure 1000K includes a fork structure 1240 that is configured to receive the electrical machine 100K and fix the electrical machine 100K thereto in a releasable manner. Electrical machine 100K includes a machine fairing 1410. The rotor boom 1180 includes a boom fairing 1110, surrounding at least partially the rotor boom 1180 and/or the fork structure 1240. The boom fairing 1110 and the machine fairing 1410 are shaped according to each other (e.g., such that when the electrical machine 100K is mounted to the fork structure 1240, a smooth (e.g., continuous) surface will result in an interface region 1420. In other embodiments, the rotor boom 1180 and/or the fork structure 1240 may be shaped such that no additional fairing is required, and where, for example, the structural wall is the outermost part or surface of the rotor boom 1180. The fork structure 1240 may be considered the continuation of the structural wall 1100 of the rotor boom 1180, where the boom fairing 1110 covers the fork structure 1240, improving the fluid dynamic properties of the rotor boom 1180 in the area of the fork structure 1240.
[0108] As shown in FIG. 17A, a mounting of the electrical machine 100K includes an insertion movement BI that is substantially parallel to a boom axis AB. Subsequently, as shown in FIG. 17B, the electrical machine 100K may be fixed to the fork structure 1240 (e.g., by bolts 214). The first group 214.1 of bolts 214 fixes the adapter plates 202, 204 to the fork structure 1240. Optionally, as shown here, a second group 214.2 of bolts 214 attach the machine fairing 1410 to the fork structure 1240 and/or the boom fairing 1110.
[0109] FIG. 18 shows yet another embodiment of an electrical machine 100L of an electrical propulsion unit 300L. A vehicle frame structure 1000L in the form of a rotor boom 1180 includes a lateral wall opening 1022 that is a wall opening 1020 that extends at least partially over a lateral wall region 1016. Accordingly, the electrical machine 100L includes a lateral adapter plate 218 that extends from the region of the bearing units 140, 160 to a radial outer region of the electrical machine 100L, to cover the lateral wall opening 1022. For example, as shown here, the lateral adapter plate 218 extends from the first bearing unit 140 via the lateral wall region 1016 to the second bearing unit 160, forming one integral piece. The lateral adapter plate 218 may be attachable to the structural wall 1100 and/or to a corresponding fork structure, allowing for an insertion movement BI that is, for example, substantially perpendicular to a boom axis BA.
[0110] FIG. 19A and FIG. 19B show, in a simplified illustration, a vehicle frame structure 1000 in the form of an airframe 1010 for an aircraft 1002. The aircraft includes a plurality of eight electrical propulsion units 300, two of which are referenced here. Each electrical propulsion unit 300 is mounted on a rotor boom 1180 and is configured to provide propulsion (e.g., lift) to the aircraft 1002. The aircraft 1002 is an electrical vertical takeoff and landing aircraft (eVTOL). However, the teachings of the present disclosure may be applied to other types of aircraft, such as electrical conventional takeoff and landing aircrafts (eCTOL), or other kind of vehicles, such as land and sea vehicles.
[0111] The elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent. Such new combinations are to be understood as forming a part of the present specification.
[0112] While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.
