Rotor, axial flux machine and drive train

Abstract

The invention relates to a rotor (6) for an electric machine (4) configured as an axial flux machine (70), wherein the disc-shaped rotor (6) has a plurality of magnet units (25) distributed in the circumferential direction over the rotor (6), wherein a magnetic flux path (72) having at least one vertex (71) extends through each of the magnet units (25) so that a first magnetic pole (73) and a second magnetic pole (74) are formed circumferentially next to one another on each magnet unit (25).

Description

[0001] Rotor, axial flux machine and drive train

[0002] The present invention relates to a rotor for an electric machine configured as an axial flux machine, wherein the disk-shaped rotor has a plurality of magnet units distributed circumferentially over the rotor. The invention further relates to an axial flux machine and a drive train of a motor vehicle.

[0003] Electric motors are increasingly being used to power motor vehicles, creating alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to provide users with the same level of driving comfort they are accustomed to.

[0004] A detailed description of an electric drive can be found in an article in the magazine ATZ, Volume 113, May 2011, pages 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled "Highly Integrative and Flexible Electric Drive Unit for E-Vehicles," which arguably represents the closest state of the art. This article describes a drive unit for a vehicle axle that includes an electric motor arranged coaxially with a bevel gear differential. Such drive units are also referred to as e-axles or electrically driven drivetrains.

[0005] Axial flux machines are also increasingly being used in such electric axles. An axial flux machine is a dynamoelectric machine in which the magnetic flux between the rotor and stator runs parallel to the rotor's axis of rotation. Both the stator and rotor are often largely disc-shaped. Axial flux machines are particularly advantageous when the axial space available is limited in a given application. This is often the case, for example, with the electric drive systems for electric vehicles described above. In addition to the shortened axial length, another advantage of the axial flux machine is its comparatively high torque density. The reason for this is the larger air gap area available in a given installation space compared to radial flux machines.Furthermore, a smaller iron volume is required compared to conventional machines, which has a positive effect on the efficiency and weight of the machine.

[0006] Due to its disc-shaped main components, an axial flux machine is particularly well-suited for applications where a very short electric motor length is essential and where a relatively large motor diameter is still acceptable. When developing such axial flux machines, it is therefore generally advisable to strive for the shortest possible design, while keeping the outer diameter of the axial flux machine no larger than absolutely necessary. Axial flux machines for automotive applications also always have to meet the requirements of low weight, high power density, and low cost.

[0007] A particular challenge in the manufacture and operation of a rotor is the design and arrangement of the magnetic elements in a rotor.

[0008] The object of the invention is therefore to realize an improved rotor and an improved axial flux machine. It is also the object of the invention to provide an optimized drive train for a motor vehicle.

[0009] This object is achieved by a rotor for an electrical machine configured as an axial flux machine, wherein the disk-shaped rotor has a plurality of magnet units arranged in a circumferential direction distributed over the rotor, wherein in each case a magnetic flux path having at least one vertex runs through one of the magnet units, so that a first magnetic pole and a second magnetic pole are formed circumferentially next to one another on the respective magnet unit.

[0010] This has the advantage that the Hallbach arrangement of the magnetic elements allows the required return path behind the magnetic elements to be reduced or even eliminated entirely. The magnetic elements then take over, at least partially, preferably completely, the deflection of the magnetic flux in the rotor. This allows the axial length of the rotor to be significantly reduced, while at the same time increasing the maximum torque that can be generated. This provides an axially particularly compact axial flux machine with a high power density, particularly for a motor vehicle drive train. The Hallbach arrangement of the magnetic elements can also have a beneficial effect on the efficiency of the axial flux machine.

[0011] A magnetic flux path in the sense of this application is a magnetic flux line of the magnetic field through the rotor, including the magnet and the material surrounding the magnet.

[0012] For the purposes of this application, the drivetrain of a motor vehicle refers to all components within the vehicle that generate the power needed to drive the vehicle and transmit it to the road via the vehicle wheels. Motor vehicles, for the purposes of this application, are defined as land vehicles that are propelled by mechanical power without being tied to railway tracks. A motor vehicle can, for example, be selected from the group of passenger cars (PCs), trucks (HGVs), mopeds, light motor vehicles, motorcycles, buses (KOMs), or tractors.

[0013] In particular, the electric axial flux machine is dimensioned such that vehicle speeds greater than 50 km / h, preferably greater than 80 km / h, and especially greater than 100 km / h can be achieved. The electric motor particularly preferably has an output greater than 30 kW, preferably greater than 50 kW, and especially greater than 70 kW. It is further preferred that the electric machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most preferably greater than 12,500 rpm.

[0014] The power electronics for supplying current to the electric machine can preferably be housed in an inverter housing. The inverter housing can preferably be formed from a metallic material, particularly preferably from aluminum, gray cast iron, or cast steel, in particular by means of a primary forming process such as casting or die-casting. The inverter housing particularly preferably has a pot-shaped spatial shape. In this context, it is particularly preferable for the housing cover to be insertable into the pot-shaped inverter housing. Alternatively, it would also be conceivable for the housing cover to rest on the pot-shaped inverter housing and cover its opening.

[0015] The inverter housing can also be part of the motor housing, or vice versa. This means that the inverter housing is formed entirely or partially in one piece, in particular monolithically, with the motor housing.

[0016] The power electronics accommodated in the inverter housing can be provided, in particular, for an electrical machine. The power electronics are preferably a combination of various components that control or regulate a current to the electrical machine, preferably including the peripheral components required for this purpose, such as cooling elements or power supplies. In particular, the power electronics contains one or more power electronic components that are designed to control or regulate a current. These are particularly preferably one or more power switches, e.g.

[0017] Power transistors. Particularly preferably, the power electronics comprises more than two, particularly preferably three, separate phases or current paths, each with at least one separate power electronics component.

[0018] The power electronics are preferably designed to control or regulate a power with a peak power, preferably continuous power, of at least 1000 W, preferably at least 10000 W, particularly preferably at least 100000 W per phase.

[0019] The power electronics preferably also includes control electronics and / or sensor electronics for the electric machine, e.g., an ACU. The power electronics module preferably includes at least one motor power connection and / or one electrical signal connection.

[0020] The rotor and / or stator can advantageously be cooled by a cooling fluid. The cooling fluid in the rotor and / or stator serves to dissipate heat as efficiently as possible from areas of the stator and / or rotor that are heating up, preventing unwanted overheating of these areas.

[0021] In addition to this primary function, the cooling fluid can also provide lubrication and corrosion protection for moving parts and the metal surfaces of the electric machine's cooling system. Furthermore, it can also remove contaminants (e.g., from abrasion), water, and air. The cooling fluid is preferably a liquid. The cooling fluid can, in particular, be an oil. However, it is also conceivable to use aqueous cooling fluids, for example, emulsions such as water-glycol mixtures.

[0022] The cooling fluid of the stator and / or rotor can be connected to a hydraulic cooling system with a hydraulic cooling circuit. Such a hydraulic cooling system serves to dissipate the heat generated within an electrical machine due to electrical losses. Such a cooling system can have cooling channels within the rotor (rotor cooling channel) and / or stator (stator cooling channel) and, in particular, also a flow through the stator slots, through which a corresponding cooling fluid is guided to dissipate the heat.

[0023] The cooling fluid can particularly preferably be pumped through the hydraulic circuit by means of a pump. It is generally conceivable for a plurality of hydraulic circuits to be configured to cool the electric machine. In this case, it is highly preferred for the cooling channels of the stator to be connected to a hydraulic cooling circuit or to various cooling circuits of the cooling system. In particular, by connecting to multiple cooling circuits, it is possible to provide more precise cooling, since, for example, the temperature of the cooling fluid upon entering the cooling channels of the stator, the flow rate of the cooling fluid, or even the type of cooling fluid (oil, emulsion) can be adjusted.

[0024] According to the invention, the electric machine is configured as an axial flux machine. Depending on the application, it may be advantageous to design an axial flux machine in an I-arrangement or an H-arrangement. In an I-arrangement, the rotor is arranged axially next to a stator or between two stators. In an H-arrangement, two rotors are arranged on opposite axial sides of a stator.

[0025] In principle, it is also possible for a plurality of I-type and / or H-type rotor-stator configurations to be arranged axially adjacent to one another. In this context, it would also be possible to arrange several I-type rotor-stator configurations axially adjacent to one another. In particular, it is also preferable for the H-type and / or I-type rotor-stator configurations to be essentially identical in design, so that they can be combined in a modular manner to form an overall configuration. Such rotor-stator configurations can, in particular, be arranged coaxially to one another and connected to a common rotor shaft or to multiple rotor shafts.

[0026] The stator of an electric axial flux machine preferably has a stator body with a plurality of stator windings arranged in the circumferential direction. The stator body can be formed as a single piece or segmented in the circumferential direction. The stator body can be formed from a stator core with a plurality of laminated electrical sheets. Alternatively, the stator body can also be formed from a pressed soft magnetic material, such as the so-called SMC (Soft Magnetic Compound).

[0027] The stator is advantageously housed in a housing. The housing can be a single-piece or multi-piece construction. Particularly preferably, the housing is made of a plastic. The housing can be closed on all sides. It is also possible to provide openings in the housing, for example, to reduce weight or to provide access to a component.

[0028] A rotor shaft is a rotatably mounted shaft of an electrical machine to which the rotor or rotor body is non-rotatably coupled.

[0029] The electric axial flux machine may further comprise a control device. A control device, as can be used in the present invention, serves in particular for the electronic control and / or regulation of one or more technical systems of the electric axial flux machine.

[0030] According to an advantageous embodiment of the invention, the magnet units can be designed to be geometrically essentially identical. This can realize manufacturing and cost advantages, which are based on the greater degree of uniformity of the corresponding rotor.

[0031] According to a further preferred development of the invention, the magnet units can also be arranged equidistantly distributed around the circumference of the rotor. This can ensure that the rotor has good concentricity and balancing properties.

[0032] Furthermore, according to a likewise advantageous embodiment of the invention, the structure securing the magnet units in the rotor can be molded from plastic, thereby making the rotor particularly lightweight and cost-effective to manufacture. Furthermore, it is preferred in this context that the magnet units are arranged in the rotor at a distance from one another in the circumferential direction.

[0033] According to another particularly preferred embodiment of the invention, the electric machine may comprise precisely one stator and one rotor. This allows for the design of a particularly compact axial flux machine.

[0034] Furthermore, the invention can also be further developed such that the magnet units are at least partially covered axially on both sides by an annular disk-like cover plate, which can contribute to axially fixing the magnet units in the rotor. For this purpose, the magnet units rest on the inner sides of the cover plates.

[0035] In a likewise preferred embodiment of the invention, it can also be provided that the cover plates are made of a plastic or an aluminum, which is advantageous both in terms of weight and cost.

[0036] It may also be advantageous to further develop the invention in such a way that the rotor is fixed to a flange of a rotor hub in a torque-transmitting manner by means of riveted connections extending in the axial direction, which can also contribute to a hybrid module that is particularly compact in axial terms, since the axial space requirement of a riveted connection is comparatively small compared to a screw connection, for example.

[0037] According to a further preferred embodiment of the subject matter of the invention, the riveted joints can be provided to penetrate the two cover plates. This ensures that the axial forces applied by the riveted joint can be dissipated effectively and over a large area via the cover plates.

[0038] Finally, the invention can also be advantageously designed such that the rotor does not have a magnetic return element, in particular no iron yoke, whereby the rotor can be designed to be particularly lightweight and axially compact and furthermore does not have any remagnetization losses.

[0039] According to an advantageous embodiment of the invention, at least one of the magnet units, preferably a plurality of the magnet units, most preferably all of the magnet units, each comprise(s) at least one isotropic magnet. The advantage of this embodiment is that it can be manufactured particularly cost-effectively.

[0040] According to a further preferred development of the invention, it can also be provided that at least one of the magnet units, preferably a plurality of the magnet units, most preferably all of the magnet units, each comprise / comprise at least one anisotropic magnet. A significant advantage of anisotropic magnets is that they can be used to achieve particularly high magnetic field strengths and flux densities. Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that at least one of the magnet units, preferably a plurality of the magnet units, most preferably all of the magnet units, each comprise / comprise a first magnet element with a first magnetic flux path and at least one second magnet element arranged adjacent to the first magnet element in the circumferential direction and having a second magnetic flux path, wherein the first magnetic flux path is different from the second magnetic flux path.The advantageous effect of this design is that the corresponding magnetic elements can be magnetized separately, which can offer advantages in terms of manufacturing and assembly. A further advantage is that stronger magnets can be provided by using separately designed magnetic elements.

[0041] According to another particularly preferred embodiment of the invention, at least one of the magnet units, preferably a plurality of the magnet units, most preferably all of the magnet units, can each have a third magnet element with a third magnetic flux path, wherein the third magnetic flux path is different from the first magnetic flux path and the second magnetic flux path. This allows the magnetic flux guidance through the magnet units to be further optimized or controlled more precisely.

[0042] Furthermore, the invention can also be further developed such that at least two of the magnetic elements, preferably all of the magnetic elements of one of the magnetic units, abut one another circumferentially. The advantage of this configuration is that a maximum amount of magnetic material can be arranged in the rotor.

[0043] In a likewise preferred embodiment of the invention, it can also be provided that at least two circumferentially adjacent magnetic elements of one of the magnetic units are spaced apart from one another in the radial direction by a support element. This can achieve a higher speed stability of the rotor. A support element can be formed, in particular, from a plastic or from aluminum. It can also be advantageous to further develop the invention such that the magnetic flux paths of the magnetic units in the rotor do not run through any soft magnetic material. The advantage that can be realized in this way is that a weight-optimized rotor can be realized without ferrous materials. Furthermore, such a rotor also has virtually no soft magnetic losses.

[0044] The object of the invention is further achieved by an axial flux machine comprising a disk-shaped rotor according to one of claims 1-8 and precisely one stator. This allows the realization of an axially particularly compact electrical machine.

[0045] Finally, the object of the invention can also be achieved by an electric drive train of a motor vehicle comprising an axial flux machine according to claim 9.

[0046] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0047] It shows:

[0048] Figure 1 shows an axial flow machine in I and H configuration in a schematic axial section,

[0049] Figure 2 shows a first embodiment of a rotor in a partially isolated, perspective detail view,

[0050] Figure 3 shows a second embodiment of a rotor in a partially isolated, perspective detail view,

[0051] Figure 4 shows a rotor in an axial section,

[0052] Figure 5 is a schematic sectional view of the first embodiment of the rotor, Figure 6 is a schematic sectional view of the second embodiment of the rotor,

[0053] Figure 7 is a schematic sectional view of a third embodiment of the rotor,

[0054] Figure 8 is a schematic sectional view of a fourth embodiment of the rotor,

[0055] Figure 9 is a schematic sectional view of a fifth embodiment of the rotor,

[0056] Figure 10 is a schematic sectional view of a sixth embodiment of the rotor,

[0057] Figure 11 shows a motor vehicle with a hybrid drive train in a schematic block diagram,

[0058] Figure 12 shows a motor vehicle with an electric drive train in a schematic block diagram.

[0059] Figure 1 shows a rotor 6 for an electric machine 4 configured as an axial flux machine 70, wherein figure a shows an axial flux machine 70 in I configuration and figure b shows an axial flux machine 70 in H configuration. Even if not explicitly shown in Figure 1, the axial flux machine 70 can in particular comprise exactly one disc-shaped rotor 6 and exactly one stator 5, and not two stators 5 as shown in figure a of Figure 1.

[0060] As can be seen from Figures 2-3, the disc-shaped rotor 6 has a

[0061] A plurality of magnet units 25 arranged distributed in the circumferential direction over the rotor 6, wherein in each case a magnetic flux path 72 having at least one vertex 71 runs through one of the magnet units 25, so that in the circumferential direction a first magnetic pole 73 and a second magnetic pole 74 are formed on the respective magnet unit 25.

[0062] At least one of the magnet units 25, preferably a plurality of the magnet units 25, most preferably all the magnet units 25, can each comprise at least one isotropic magnet. It is also possible for at least one of the magnet units 25, preferably a plurality of the magnet units 25, most preferably all the magnet units 25, to each comprise at least one anisotropic magnet.

[0063] Figure 3 shows a disk-shaped rotor 6 for an electric machine 4 configured as an axial flux machine 70, which has a plurality of magnet units 25 arranged circumferentially distributed over the rotor 6. Such a rotor 6 is installed, for example, in the embodiment shown in Figure 1.

[0064] Each of the magnet units 25 of Figure 3 has a first magnet element 26, a second magnet element 27, and a third magnet element 28, wherein the first magnet element 26 and the second magnet element 27 have a first contact surface 29 extending in the radial direction, and the second magnet element 27 and the third magnet element 28 have a second contact surface 30 extending in the radial direction. The embodiment of Figure 2 has only two magnet elements 26, 27.

[0065] The magnetic elements 26, 27, 28 in Figures 2-3 are now magnetized to form a Hallbach array. The resulting magnetic flux through the magnet units 25 is indicated by the dashed arrows in Figures 2 and 3.

[0066] The magnet units 25 are geometrically essentially pie-shaped and identical, and are arranged equidistantly distributed around the circumference of the rotor 6. Preferably, the magnet units 25 are enclosed in the rotor 6 by a fixing structure made of plastic. The Hallbach arrangement of the magnet elements 26, 27, 28 makes it possible for the electric machine 4 to have exactly one stator 5 and one rotor 6, thus allowing it to be designed to be particularly compact axially while simultaneously maintaining a high power density. This is also supported by the fact that the rotor 6 does not have a magnetic return element, in particular no iron yoke.

[0067] To protect the magnet units 25 from mechanical influences and to secure them axially in the rotor, they are covered at least partially on both sides by an annular disk-like cover disk 31, which can be clearly seen in Figure 4. The cover disks 31 can also be designed in a segmented manner in the circumferential direction. The cover disks 31 are made of a plastic or aluminum.

[0068] Figure 4 also clearly shows that the rotor 6 is fixed to a flange 33 of the rotor hub 34 by means of riveted joints 32 extending in the axial direction, transmitting torque. The riveted joints 32 each penetrate the two cover plates 31 of the rotor 6. The magnet units 25 are secured radially in the rotor 6 by the annular bandage element 35. Figure 4 shows an embodiment of a rotor hub 34 with a flange 33, in which the rotor 6 is also supported in the radial direction by the riveted joints 32.

[0069] As shown in Figure 5, the magnet units 25 can each have a first magnet element 26 with a first magnetic flux path 77 and at least one second magnet element 27 arranged circumferentially adjacent to the first magnet element 26 with a second magnetic flux path 78, wherein the first magnetic flux path 77 is different from the second magnetic flux path 78, so that different magnetic poles can be formed. These poles are indicated in Figure 5 with N for north pole and S for south pole. The air gap 50 is formed between the stator 5 and the rotor 6. This results in a magnetic flux path 72 having an apex 71, which runs through each of the magnet units 25, so that a first magnetic pole 73 and a second magnetic pole 74 are formed on the respective magnet unit 25 in the circumferential direction.

[0070] Figure 6 shows a further embodiment of the rotor 6, in which the magnet units 25 each have a third magnet element 28 with a third magnetic flux path 79, wherein the third magnetic flux path 79 is different from the first magnetic flux path 77 and the second magnetic flux path 78. The magnet elements 26, 27, 28 of one of the magnet units 25 abut one another in the circumferential direction. This results in a magnetic flux path 72 having a first vertex 71a and a second vertex 71b, which runs in an arc through each of the magnet units 25, so that a first magnetic pole 73 and a second magnetic pole 74 are formed on the respective magnet unit 25 in the circumferential direction.

[0071] What can be seen from Figure 7 is that at least two circumferentially adjacent magnetic elements 26, 27 of one of the magnetic units 25 are spaced apart from one another in the circumferential direction by a support element 80. The support elements 80 are designed and arranged in a spoke-like manner and bear against the circumferentially adjacent magnetic elements 26, 27, so that the comparatively brittle magnetic elements 26, 27 do not rub against one another during operation of the rotor 6.

[0072] The embodiment of Figure 8 is formed from two isotropic magnetic elements 26, 27, in which a magnetic flux path 72 with a vertex 71 is already defined.

[0073] Figure 9 shows an embodiment variant of the rotor 6, in which a magnet unit 25 consists of an isotropic magnet element 26 and four anisotropic magnet elements 28,81,82,83, wherein the isotropic magnet element 26 defines the north pole and the four anisotropic magnet elements 28,81,82,83 define the magnetic south pole.

[0074] Figure 10 shows a modification of the rotor 6 known from Figure 8, in which a total of eight anisotropic magnetic elements 26,27,28,81,82,83,84,85 are used to form the magnetic poles 73,74 instead of two isotropic magnetic elements 26,27.

[0075] The magnetic flux paths 72 of the magnet units 25 in the rotor 6, as shown in the exemplary embodiments, do not run through any soft magnetic material.

[0076] The axial flux machine 70 can, for example, be installed in a hybrid module 1 of a motor vehicle 3, as shown in Figure 11. Here, the hybrid module 1 is positioned between the internal combustion engine 11 and a transmission 24 in the drive train 2. It is also possible to integrate the axial flux machine 70 into a purely electric drive train 2 of a motor vehicle 3, as outlined in Figure 12.

[0077] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood in such a way that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority.

[0078] List of reference symbols

[0079] 1 hybrid module

[0080] 2 Drivetrain

[0081] 3 Motor vehicle

[0082] 4 electric machine

[0083] 5 Stator

[0084] 6 Rotor

[0085] 11 Internal combustion engine

[0086] 24 gearboxes

[0087] 25 magnet units

[0088] 26 Magnetic element

[0089] 27 Magnetic element

[0090] 28 Magnetic element

[0091] 29 Contact surface

[0092] 30 contact area

[0093] 31 Cover plate

[0094] 32 riveted joint

[0095] 33 flange

[0096] 34 Rotor hub

[0097] 35 Bandage element

[0098] 50 air gap

[0099] 70 axial flux machine

[0100] 71 Vertex

[0101] 72 Magnetic flux path

[0102] 73 poles

[0103] 74 poles

[0104] 77 Magnetic flux path

[0105] 78 Magnetic flux path 79 Magnetic flux path

[0106] 80 supporting element

[0107] 81 Magnetic element

[0108] 82 Magnetic element 83 Magnetic element

[0109] 84 Magnetic element

[0110] 85 Magnetic element

Claims

Claims 1. Rotor (6) for an electrical machine (4) configured as an axial flux machine (70), wherein the disc-shaped rotor (6) has a plurality of magnet units (25) arranged distributed in the circumferential direction over the rotor (6), characterized in that in each case a magnetic flux path (72) having at least one vertex (71) runs through each of the magnet units (25), so that a first magnetic pole (73) and a second magnetic pole (74) are formed circumferentially next to one another on the respective magnet unit (25).

2. Rotor (6) according to claim 1, characterized in that at least one of the magnet units (25), preferably a plurality of the magnet units (25), most preferably all of the magnet units (25), each comprise / comprise at least one isotropic magnet.

3. Rotor (6) according to one of the preceding claims, characterized in that at least one of the magnet units (25), preferably a plurality of the magnet units (25), most preferably all of the magnet units (25), each comprise / comprise at least one anisotropic magnet.

4. Rotor (6) according to one of the preceding claims, characterized in that at least one of the magnet units (25), preferably a plurality of the magnet units (25), most preferably all the magnet units (25), each have a first magnet element (26) with a first magnetic flux path (77) and at least one adjacent magnet element (26) in the circumferential direction arranged second magnetic element (27) with a second magnetic flux path (78), wherein the first magnetic flux path (77) is different from the second magnetic flux path (78).

5. Rotor (6) according to one of the preceding claims, characterized in that at least one of the magnet units (25), preferably a plurality of the magnet units (25), most preferably all of the magnet units (25), each has / have a third magnet element (28) with a third magnetic flux path (79), wherein the third magnetic flux path (79) is different from the first magnetic flux path (77) and the second magnetic flux path (78).

6. Rotor (6) according to one of the preceding claims, characterized in that at least two of the magnetic elements (26, 27, 28), preferably all magnetic elements (26, 27, 28) of one of the magnetic units (25) abut one another in the circumferential direction.

7. Rotor (6) according to one of the preceding claims, characterized in that at least two circumferentially adjacent magnetic elements (26, 27, 28) of one of the magnetic units (25) are spaced from one another in the circumferential direction by a support element (80).

8. Rotor (6) according to one of the preceding claims, characterized in that the magnetic flux paths (72) of the magnet units (25) in the rotor (6) do not run through any soft magnetic material.

9. Axial flux machine (70) comprising a disk-shaped rotor (6) according to one of the preceding claims and exactly one stator (5).

10. Electric drive train (2) of a motor vehicle (3) comprising a Axial flow machine (70) according to claim 9.

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