Transverse flux machine

Abstract

The invention relates to a transverse flux machine having: a rotor (11) that is provided with permanent magnets (5) and has an axis of rotation (110) that defines an axial direction, a radial direction and a circumferential direction; and a stator (12) and active parts (7, 8) of the stator (12), including a coil winding (8). Provision is made for the stator (12) to be in the form of a ring structure having a multiplicity of ribs (120) that adjoin one another in the circumferential direction and each form a cooling air channel (121) therebetween, the ribs (120) being intended and designed to hold and to position the active parts (7, 8) of the stator (12).

Description

[0001] Transverse flux machine

[0002] Description

[0003] The invention relates to a transverse flux machine.

[0004] A transverse flux machine is a rotating electrical machine in which a relevant magnetic flux is established essentially transversely or perpendicularly to a rotational axis of at least one rotor of the transverse flux machine. The stator winding is designed as a circumferential winding arranged concentrically to the rotational axis of the rotor. The transverse flux machine is often designed as a permanent-magnet synchronous machine and can be configured for application of a single-phase or multi-phase alternating voltage. In principle, a transverse flux machine can also be designed as an asynchronous machine. The design of the transverse flux machine allows magnetic and electrical circuits to be constructed largely independently of one another. Furthermore, axial winding overhangs, which generally do not contribute to torque generation, can be largely avoided.

[0005] US 2021 / 0099036 A1 discloses a transverse flux machine in which the stator poles and the stator winding are fluid-cooled. This is achieved by arranging individual stator poles spaced apart from one another in the circumferential direction, so that a cooling fluid can flow between adjacent stator poles. The cited document does not address the provision of a suitable cooling flow. The present invention is based on the object of providing a transverse flux machine designed in such a way that fluid cooling with good cooling properties can be realized.

[0006] This object is achieved by a transverse flux machine having the features of claim 1. Embodiments of the invention are specified in the dependent claims.

[0007] Accordingly, the present invention contemplates a transverse flux machine comprising a rotor provided with permanent magnets and having an axis of rotation, wherein the axis of rotation defines an axial direction, a radial direction, and a circumferential direction of the transverse flux machine. The transverse flux machine further comprises a stator and active components of the stator, wherein the active components comprise a coil winding.

[0008] It is provided that the stator is designed as a ring structure with a plurality of ribs which are adjacent to one another in the circumferential direction and which each form a cooling air channel between them, wherein the ribs are provided and designed to hold and position the active components of the stator.

[0009] Accordingly, the present invention is based on the idea of ​​designing the stator with circumferentially spaced ribs that fulfill a dual function. Firstly, the ribs fulfill a holding and positioning function by holding and appropriately positioning the active components of the stator. Secondly, due to their circumferential spacing, the cooling ribs provide cooling air channels that allow the active components to be cooled with a fluid flow that flows radially through the cooling air channels.

[0010] The design according to the invention thus enables direct fluid cooling, in particular air cooling, of the active components of the stator. The fluid cooling is provided by a fluid flow, in particular an air flow, which can be forced (for example, through the use of fans) or which can result from the pressure differences that arise in different areas of the transverse flux machine during operation. Direct fluid cooling effectively allows direct convection cooling of the surfaces of the active components of the stator that are to be cooled. In general, the cooling fluid can be a liquid or a gas such as air. The active components of the stator are, in particular, stator poles (also referred to as stator yokes or iron cores) and coil windings, as will be explained below. These are cooled directly by means of convection cooling.

[0011] One embodiment of the invention provides that the rotor of the transverse flux machine is designed as an externally rotating rotor, with, for example, permanent magnets of the rotor being axially offset from the stator and structural parts of the rotor being arranged radially outside the stator. Alternatively, the transverse flux machine can be designed with an internally rotating rotor.

[0012] A further embodiment provides that the rotor comprises axially spaced outer walls, each of which has or integrates permanent magnets, as well as an end wall provided with radial openings. The radial openings are provided and designed to direct cooling fluid flowing through the cooling air ducts of the stator into the environment or to direct it from the environment toward the cooling air ducts. Such radial openings in the rotor or generally in an outer wall of the transverse flux machine are necessary so that the radial fluid flow realized in the stator according to the invention can be released into the environment or absorbed by the environment.

[0013] Furthermore, it can be provided that the active components of the stator, which are held by the stator ribs, are arranged in a volume delimited by the aforementioned outer walls and the end wall of the rotor. This is particularly useful in a configuration in which the rotor and the stator form an air gap extending in the radial direction and circumferentially (with an air gap normal vector pointing in the axial direction). Thus, in the aforementioned design, an air gap runs between the active components of the stator and the permanent magnets of the rotor, each adjacent to the inner side of the outer walls of the rotor.

[0014] In general, it should be noted that the air gap is the actual physical gap in an electric motor that separates the rotor and stator. The air gap should be sufficiently large to prevent contact between the rotor and stator, taking tolerances into account. It should also be as small as possible to maximize electromagnetic interaction between the rotor and stator. Furthermore, the air gap should be uniform. An asymmetrical air gap can, for example, lead to axial or radial imbalance forces between the rotor and stator and / or damage, for example, to the insulation.

[0015] The permanent magnets are designed, for example, as surface-mounted permanent magnets, whereby in principle any known construction can be used.

[0016] A further embodiment provides that the active components of the stator are arranged and designed such that a fluid flow flowing radially through the cooling air channels flows past the surfaces of the active components and cools them. Different embodiments provide for the fluid flow to flow from radially inside to radially outside or from radially outside to radially inside. The flow direction depends on the prevailing pressure conditions and any fans used.

[0017] It can be provided that the active components of the stator are arranged in functional units, which each extend in the radial direction and over a circumferential segment in the circumferential direction and which are each held by a plurality of the ribs, wherein the functional units each have: two axially spaced, non-magnetic and non-magnetizable holding plates, stator poles extending between the holding plates, which have a

[0018] Define a winding space extending in the circumferential direction, in which a coil winding extending in the circumferential direction is arranged, wherein a fluid flow flowing through the cooling air channels flows radially through the functional units between the two holding plates and flows past the stator poles and the coil winding.

[0019] This design thus provides several functional units, each providing stator poles and a winding space with a coil winding, and each connected to stator ribs. The functional units can be modular, prefabricated units that extend radially into the aforementioned volume between the axially spaced outer walls of the rotor, with a radial fluid flow for cooling being feasible in each functional unit.

[0020] The coil winding is segmented, with each functional unit containing a coil segment and several functional units and coil segments arranged adjacent to one another in the circumferential direction. For example, the transverse flux machine is designed for operation with a three-phase alternating voltage. For this purpose, each of the coil segments is supplied with a respective phase of the alternating voltage. The alternating voltage is thus a three-phase alternating voltage.

[0021] It should be noted that the fluid flow passing through the stator's cooling air channels does not necessarily flow entirely through the functional units. A portion may also flow past them through the air gap between the outer wall of the rotor and the adjacent support plate of the functional unit (i.e., through the electromagnetically relevant air gap between the rotor and stator). In certain embodiments, such an air flow can be used to cool the rotor's permanent magnets.

[0022] A further embodiment provides that the coil winding has at least two winding packs spaced apart from one another in the axial direction and / or that the coil winding is spaced apart from the retaining plates in the axial direction. This provides a cooling air flow channel that runs between the axially spaced winding packs and / or cooling air flow channels are provided that flow between the coil winding and the respective retaining plate. In such cooling air flow channels, the cooling air or cooling fluid flows in a radial direction or slightly inclined to the radial direction.

[0023] In one embodiment, the two aforementioned embodiments are combined, so that the coil winding has at least two axially spaced winding packages, which are spaced apart in the axial direction both from each other and from the holding plates. The functional unit forms at least three radially extending and axially spaced cooling air flow channels for cooling the winding packages. Thus, one cooling air flow channel comprises an area that extends between one holding plate and one winding package. Another cooling air flow channel comprises an area that extends between the winding packages. A third cooling air flow channel extends between the other winding package and the other holding plate. With more than two axially spaced winding packages, the number of cooling air flow channels increases accordingly.

[0024] By providing axially spaced winding packs, the surface area of ​​the coil winding accessible to cooling is increased compared to a single winding pack. The winding packs can be cooled simultaneously on both their top and bottom surfaces. In one embodiment, the winding packs are dimensioned with respect to the number of winding wires such that each of the winding wires can be cooled at least in a partial area of ​​its surface. In the event that the individual winding wires in the winding packs are arranged at a distance from one another, which may be the case in exemplary embodiments, the cooling fluid can also flow around and cool each individual winding wire separately.

[0025] Improved cooling of the coil winding or individual winding packages is also achieved by axially spacing the coil winding from the holding plates.

[0026] A further embodiment provides for the stator poles to be radially aligned and have radially aligned side surfaces spaced apart in the circumferential direction. This allows for effective convection cooling of the stator poles across both side surfaces.

[0027] A further embodiment provides that the stator poles are each curved and arranged in at least two mutually associated circumferential rows, wherein the at least two circumferential rows are radially spaced apart, the stator poles of the two circumferential rows are each arranged offset from one another in the circumferential direction, the stator poles of the radially inner circumferential row are concavely curved when viewed from the radial outside and the stator poles of the radially outer circumferential row are convexly curved when viewed from the radial outside, so that their mutually facing sections together define the winding space or a partial winding space, wherein they delimit the winding space transversely to the circumferential direction, and the ends of the stator poles form pole heads which adjoin the rotor and which are each arranged in one of the holding plates.

[0028] This design provides for the provision of winding spaces or partial winding spaces, each consisting of two rows of offset and curved stator poles. The individual stator poles can be designed in accordance with US 2021 / 0099036 A1. The pole heads of the stator poles, which interact electromagnetically with the permanent magnets of the rotor, are secured to the retaining plates.

[0029] One embodiment provides for the stator poles to be arranged in at least four circumferential rows, wherein two of the circumferential rows are assigned to one another and form a partial winding space, wherein the partial winding spaces extend radially spaced apart in the circumferential direction, and wherein sections of the coil winding which extend longitudinally in the circumferential direction are arranged in the partial winding spaces (which sections are bent or returned by 180° at the circumferential ends of the coil windings).

[0030] A further embodiment provides for the coil winding to be fixed in the winding space in sections by a fixing material. These sections extend only slightly in the circumferential direction so as not to impede cooling of the coil winding by the cooling fluid flow. According to one embodiment, the fixing material is arranged in alignment with the stator poles (and thus, to a certain extent, in their slipstream) in the direction of flow of the cooling fluid in order to impede the cooling fluid flow as little as possible. These sections are not wider in the circumferential direction than the stator poles.

[0031] It should be noted that the stator poles have base bodies which, in a conventional manner, can consist of laminated cores or of a soft magnetic composite (SMC) in order to reduce eddy currents as far as possible.

[0032] It is further pointed out that particle filters and / or particle separators can be integrated into the transverse flux machine at several points, which clean the fluid flow, in particular before it enters the stator, so that the coil winding is protected from particle damage and particle deposition.

[0033] A further embodiment provides that the transverse flux machine has a first end facing a load to be driven and a second end facing away from the load to be driven, and that the transverse flux machine forms openings at its first end or at its second end which, during operation, enable a fluid flow which flows in the radial direction or counter to the radial direction through the cooling air channels and the active components of the stator of the electric motor unit.

[0034] This aspect of the invention is based on the idea of ​​providing a suitable fluid flow, particularly air flow, in the transverse flux machine according to the invention when the transverse flux machine is in operation. For this purpose, openings are provided which, in conjunction with pressure differences arising during operation or active elements such as fans, create a fluid flow within the radially aligned cooling air channels of the stator. The pressure differences arising during operation arise, for example, from the air flow of a propeller driven by the transverse flux machine and from the dynamic pressure of the aircraft driven by the propeller.

[0035] One embodiment provides for the openings to be formed at the first end, which faces a load to be driven, and the second end to be tightly closed. The latter is the case so that incoming cooling fluid cannot immediately leave the machine again. The transverse flux machine is designed to direct cooling fluid flowing through the openings radially outward through the cooling air ducts and the active components of the stator.

[0036] Alternatively, the situation is reversed, with the openings located at the second end and the first end tightly closed. Again, the transverse flux machine is designed to direct cooling fluid flowing through the openings radially outward through the cooling air ducts and the active components of the stator.

[0037] In the two aforementioned variants, the cooling fluid is guided radially outwards in the stator. However, this is not necessarily the case. Alternatively, it can be provided that the cooling fluid is guided radially inwards in the stator. Thus, a further embodiment provides that the openings are formed at the first end or at the second end (with the other end closed in each case), wherein the

[0038] Transverse flux machine is designed to be driven from the outside of the

[0039] To guide the cooling fluid received from the transverse flux machine from the radial outside to the radial inside through the active components and the cooling air ducts. For this purpose, the transverse flux machine, in particular the rotor, may have guide elements on its outer side that are designed to redirect cooling fluid flowing in the axial direction through openings toward the active components of the stator and the cooling air ducts.

[0040] According to one embodiment, at least one fan (e.g. per cooling air duct or multiple cooling ducts of the stator) is provided, which conveys the cooling fluid in a desired direction. Such a fan can generate an axial or a radial air flow, depending on the arrangement. Exemplary embodiments provide for a fan to be arranged on the outside of the rotor (with radial flow generation) or on a rotor shaft (with axial flow generation). In a further aspect of the invention, an electric drive unit is provided. The electric drive unit comprises an electric motor unit with a rotor and a stator, wherein the motor unit is designed as a transverse flux machine according to claim 1. Furthermore, the electric drive unit comprises a bearing unit having an axially arranged, rotatable output shaft and a static bearing part that supports the output shaft.The output shaft has an interface for connection to a load to be driven.

[0041] A clutch unit is further provided which provides a torque transmission from the rotor to the output shaft, wherein the rotor is arranged radially spaced from the output shaft and the clutch unit comprises clutch means which extend in the radial direction between the rotor and the output shaft.

[0042] This aspect of the invention is based on the idea of ​​dispensing with a rigid and direct coupling between the rotor of the motor unit and the output shaft and instead providing an additional coupling unit that provides torque transmission between the radially outer rotor and the axially arranged output shaft. The use of radially extending coupling means for such a coupling opens up the possibility of providing these coupling means with a defined, desired rigidity that meets the respective requirements.

[0043] In particular, the coupling unit can be provided with a soft coupling between the rotor and the output shaft, meaning that it has low rigidity with respect to lateral forces, axial forces, and / or bending forces introduced into the coupling via the output shaft by the load. Such forces are therefore mitigated and not transmitted to the rotor, or only transmitted to a reduced extent, thus decoupling it from externally introduced forces. Since such forces can lead to an asymmetry in the air gap between the rotor and stator, the use of a coupling unit with a defined, low rigidity prevents irregularities in the air gap.

[0044] Embodiments provide that the coupling unit realizes a soft or flexible coupling between the rotor and the output shaft in the sense that forces and imbalances introduced into the coupling by the load do not significantly influence the gap between the rotor and stator of the motor unit, wherein a non-significant influence in the sense of the present invention exists if the air gap deviation does not exceed a value of ± 20% of the average air gap, in particular of ± 10% of the average air gap.

[0045] A further advantage is that by avoiding, or largely avoiding, an asymmetry of the air gap, it is possible to create it more precisely and thus with a shorter length. This can result in weight savings and increase the efficiency of the electric motor.

[0046] A further advantage is that this solution enables the provision of a drive unit with a modular design, with the motor unit, bearing unit, and clutch unit being modular prefabricated units connected to each other via defined mechanical interfaces. The individual units represent different structural and functional components of the electric motor. They can be developed, tested, or even replaced independently of one another—for example, after a design update. Defined mechanical interfaces are important for this, ensuring the connection and detachment of the respective units.

[0047] One embodiment provides that the clutch has a clutch disc as coupling means, which is coupled radially outward to the rotor and radially inward to the shaft. A clutch disc inherently has high torsional rigidity and low flexural rigidity or transverse rigidity, whereby the exact value can be determined by the material and design of the clutch disc. Bending rigidity or transverse rigidity refers to the stiffness with respect to axially introduced forces. Axial forces introduced into the drive unit by a load such as a propeller lead to a local axial deformation of the clutch disc without the deformation being transferred to the radially outer region of the clutch disc and thus to the rotor. The rotor is thus largely decoupled from axial forces introduced from the load side.The same applies to lateral forces that are introduced on the load side and act on the clutch disc.

[0048] It should be noted that a clutch disc is any structure whose axial dimension is small compared to its radial dimension (where the ratio of axial dimension to radial dimension is, for example, less than 1 / 10). This does not preclude the clutch disc from having recesses and / or deviating from a strictly radial dimension. It should also be noted that, for example, a diaphragm clutch can be used as the coupling means instead of a clutch disc.

[0049] In general, it is pointed out that the coupling means, in addition to a radial extension between the rotor and the output shaft, can also have an axial extension in the sense that the radially inner region of the coupling means is axially offset from the radially outer region of the coupling means.

[0050] One design variant provides for the coupling means to be connected radially inward to a shaft journal that extends into the output shaft and drives it, for example, through positive engagement. However, this is not necessarily the case. Alternatively, the coupling means can be connected radially inward directly to the output shaft. Radially outward, the coupling means are connected directly to the rotor, for example, via bolts or other fastening means.

[0051] As already mentioned, the clutch unit can be designed as a torsionally rigid clutch or one with high torsional rigidity. This allows torque transmission between the rotor and the output shaft with essentially no backlash. For example, the angle of rotation between the rotor and the output shaft, which is created by the torque applied by the rotor, can be provided to be no greater than 0.1°.

[0052] A further embodiment provides for the bearing unit to have an axially front bearing and an axially rear bearing for supporting the output shaft. The bearings can be designed to allow axial play of the output shaft. For this purpose, they are designed, for example, as floating support bearings, with a slight play being provided in the axial direction. Such a bearing arrangement ensures that axial forces introduced on the load side do not load the bearings, but are absorbed by the coupling means, for example, the clutch disc.

[0053] A further embodiment of the invention provides that the output shaft has the greatest axial extent compared to the motor unit and the coupling unit and widens conically in the direction of a load to be driven. This makes it possible to provide a large-area and secure interface for connecting to a load, for example a propeller. The interface is provided, for example, by a flange connection. A further embodiment provides that the static bearing part of the bearing unit has a mechanical interface for connecting the bearing unit to the airframe of an aircraft. The static connection to the airframe is thus achieved via the static bearing part. Such a connection can be achieved via an elastic coupling, as provided, for example, by so-called "shock mounts".

[0054] As already mentioned, one embodiment provides that the motor unit, the bearing unit, and the coupling unit represent modular, prefabricated units that are connected to one another via defined mechanical interfaces. According to one exemplary embodiment, the interfaces are defined by the type of connecting structures, their position or spatial coordinates on the respective unit, and the associated connecting elements. The exact type and position of the connecting structures on the respective unit (e.g., flanges at a defined position) as well as the type of connecting means or connecting elements (e.g., screw connection, bolt connection, adhesive connection) are thus predefined.

[0055] One embodiment provides for the stator of the motor unit and the static bearing part to form a mechanical interface for interconnecting them. Such a mechanical interface can integrate an elastic coupling, such as that provided by shock mounts. Another embodiment provides for the rotor of the motor unit and a radially outer region of the clutch unit to form a mechanical interface for interconnecting them. Furthermore, it can be provided that a radially inner region of the clutch unit and the output shaft form a mechanical interface for interconnecting them.

[0056] One embodiment provides for the stator to be designed as a ring structure with a plurality of ribs that are adjacent to one another in the circumferential direction and each form a cooling air channel between them. The ribs hold and position the active components of the stator (in particular the stator windings). The provision of ribs that each form a cooling air channel between them enables effective cooling, particularly of the coils or windings of the electric motor.

[0057] According to one embodiment, the rotor of the electric motor unit is mounted relative to the stator via a separate bearing, whereby this separate bearing is different from the bearing for the output shaft of the bearing unit. When using a coupling unit that implements a soft coupling, the separate rotor bearing only needs to absorb low loads. Thus, lateral forces, axial forces, and / or bending forces are mitigated by the coupling unit and transmitted to the rotor to a reduced extent.

[0058] For example, the electric motor unit is a permanent magnet synchronous motor. In a permanent magnet synchronous motor, the stator is equipped with coils, while surface magnets are attached to the rotor. The alternating voltage is applied to the stator coils.

[0059] The invention is explained in more detail below with reference to the figures of the drawing using several exemplary embodiments. They show:

[0060] Figure 1 shows a partially sectioned view of a first embodiment of an electric drive unit comprising a motor unit, a bearing unit and a clutch unit, wherein the motor unit is designed as a transverse flux machine with an externally rotating rotor;

[0061] Figure 2 shows the motor unit and the clutch unit of the electric drive unit of Figure 1 in a partially sectioned, perspective view;

[0062] Figure 3 shows the electric drive unit of Figure 1 in a partially sectioned, perspective view;

[0063] Figure 4 is a perspective view of the top of the electric drive unit of Figure 1;

[0064] Figure 5 is a perspective view of the underside of the electric drive unit of Figure 1;

[0065] Figure 6 shows a partially sectioned view of a second embodiment of an electric drive unit comprising a motor unit, a bearing unit and a clutch unit, wherein the motor unit is designed as a radial flux machine with an internally rotating rotor;

[0066] Figure ? the rotor of the motor unit and the coupling unit of the electric drive unit of Figure 6 in a partially sectioned, perspective view; Figure 8 schematically shows an embodiment of an electric drive unit which comprises a transverse flux machine with an externally rotating rotor and a bearing unit according to Figures 1 to 5, wherein the transverse flux machine has two rotor-stator assemblies which are arranged one behind the other in the axial direction and are firmly connected to one another, and wherein a cooling air flow is realized which flows radially outwards through the active components of the stator from a side facing a load to be driven;

[0067] Figure 9 shows an electric drive unit according to Figure 8, wherein a cooling air flow is realized which flows radially outwards through the active components of the stator from a side facing away from a load to be driven;

[0068] Figure 10 shows an electric drive unit according to Figure 8, wherein a cooling air flow is realized which flows radially inwards through the active components of the stator;

[0069] Figure 11 is a perspective, partially sectioned view of an embodiment of a functional unit of the stator, which is attached to ribs of the stator, the functional unit comprising axially spaced support plates, stator poles extending between the support plates and a coil winding extending in the circumferential direction;

[0070] Figure 12 shows the functional unit of Figure 11 in a complete perspective view; and

[0071] Figure 13 is a sectional view of the functional unit of Figures 11 and 12.

[0072] Figures 1 to 5 show various views of a first exemplary embodiment of an electric drive unit. The electric drive unit comprises an electric motor unit 1, a bearing unit 2 with an output shaft 21 and a static bearing part 22, and a clutch unit 3. The three units 1, 2, 3 represent modular units that can be manufactured separately and connected to one another via defined mechanical interfaces, as will be explained below. The description of the first exemplary embodiment refers to all of Figures 1 to 5, unless specific reference is made to certain of the figures. The electric motor unit 1 comprises a rotor 11 and a stator 12. In the exemplary embodiment shown, the motor unit 1 is designed as a transverse flux machine, in which the rotor 11 is designed as an externally rotating rotor 11. Such motor units 1 are also referred to as transverse flux motors.

[0073] The rotor 11 has two axially spaced outer walls 111, 112, each of which has or integrates permanent magnets (not shown separately) aligned in the radial direction. The two outer walls 111, 112 are connected to one another by a radially outer, end wall 113. The stator 12 is formed by a ring structure with a plurality of ribs 120, which adjoin one another in the circumferential direction and each form a cooling air channel 121 between them. The individual ribs 121 hold the active components of the stator 12, which are arranged in the volume 122 defined by the outer walls 111, 112 and the end wall 113 of the rotor 11. The active components (not shown separately) are in particular electromagnets, i.e. coil windings and possibly associated metal cores.In the stator 12, several circumferential windings are realized, which are arranged at the same distance from the central axis of symmetry of the drive unit in the circumferential direction.

[0074] In such a transverse flux motor configuration, an air gap 131 extends between the rotor 11 and the stator 12 (namely, the air gap 131 between the permanent magnets of the rotor 11 and the active components of the stator 12) such that the air gap 131 extends radially and thereby encircles the electric motor 1 in the circumferential direction. In the described design, two air gaps are provided, each adjacent to the outer walls 111, 112 on the inside.

[0075] The rotor 11 and the stator 12 are connected to each other via an axially front bearing 141 and an axially rear bearing 142 so that the rotor 11 can rotate around the stator 12.

[0076] In alternative embodiments, the motor unit 1 can have several rotor-stator assemblies of the type described, which are arranged one behind the other in the axial direction and are firmly connected to one another.

[0077] The bearing unit 2 comprises the output shaft 21 and the static bearing part 22. The output shaft 21 has a rotational and longitudinal axis (not shown separately) that is identical to the axis of symmetry of the overall arrangement, with the rotational and longitudinal axis defining the axial direction of the drive unit. The static bearing part 22 serves to support the output shaft 21. For this purpose, the bearing unit 2 comprises an axially front bearing 24 and an axially rear bearing 25. The bearings 24, 25 can be designed such that a certain axial play of the output shaft 21 is permitted.

[0078] The static bearing part 22 has a plurality of ribs or stiffeners 27 arranged in the circumferential direction. Furthermore, the static bearing part 22 comprises a base structure extending in the radial direction, for example, a base plate 260, which can form a mechanical interface 26 on its radially outer region for connecting the bearing unit 2 and thus the entire drive unit to a static structure, for example, the airframe of an aircraft. Instead of a base plate 260, the base structure can be formed, for example, by a plurality of interconnected, radially extending arms.

[0079] The rotationally symmetrical output shaft 21 comprises an axially front end 211, which is coupled to a shaft journal 32 of the coupling unit 3 and is driven by the electric motor unit 1, as will be explained below. The shaft journal 32 can be formed integrally with the coupling unit 3. Furthermore, the output shaft 21 comprises an axially rear end 212, which forms an interface 23 for connection to a load to be driven. For example, a propeller as a load can be connected to the output shaft 21 via the interface 23. The interface 23 comprises, for example, openings 231 for implementing screw connections or bolt connections. The output shaft 21 widens conically between the axially front end 211 and the axially rear end 212.The axial length of the output shaft 21 is greater than the axial height of the motor unit 1 and the clutch unit 3, so that the output shaft 21 protrudes axially relative to the latter.

[0080] However, this is only an example. Depending on the bearing selection and application, the output shaft 21 can also have a shape other than conical. Alternatively, the axial length of the output shaft 21 can also be provided not to exceed the axial height of the motor unit 1.

[0081] The output shaft 21 is pre-assembled in the static bearing part 22, so that the output shaft 21 and bearing part 22 together form the modular bearing unit 2.

[0082] The coupling unit 3 serves to transmit the torque of the rotor 11 of the motor unit 1 to the output shaft 21. The rotor 11 is radially spaced from the output shaft 21. Accordingly, the coupling unit 3 has coupling means that extend radially between the rotor 11 and the output shaft 21.

[0083] In the illustrated embodiment, these coupling means are provided by a clutch disc 31, although this is not necessarily the case. For example, the coupling means may alternatively be formed by a plurality of radially extending and circumferentially spaced struts or spokes, similar to a bicycle hub, or by a diaphragm coupling.

[0084] The clutch disc 31 is coupled radially outwardly to the rotor 11 and radially inwardly to the output shaft 21. The coupling of the clutch disc 31 to the rotor 11 is achieved via a predefined mechanical interface 42 comprising bolts 421 that non-rotatably connect the radially outer edge 312 (see Figure 2) of the clutch disc 31 to the axially front wall 112 of the rotor 11.

[0085] The coupling of the clutch disc 31 to the output shaft 21 takes place via the aforementioned shaft journal 32. The radially inner edge 311 (see Figure 2) of the clutch disc 31, which has a central recess, is connected in a rotationally fixed manner to the shaft journal 32 via a mechanical interface 43 comprising bolts 431. The shaft journal 32 comprises an axially projecting region 321 which projects into the axially front end 211 of the output shaft 21 and, due to a positive connection between the shaft journal 32 and the axially front end 211 of the output shaft 21, transmits a torque to the output shaft 21. In addition, a mechanical connection 44 with bolts 441 can be provided for the rotationally fixed connection between the shaft journal 32 and the axially front end 211 of the output shaft 21. The shaft journal 32 can alternatively be integrated into the clutch disc 31.

[0086] Alternatively, the clutch disc 31 is connected directly to the output shaft 21, without the interposition of a shaft journal 32.

[0087] To connect the motor unit 1 and the bearing unit 2, a mechanical interface 41 is provided, which connects the motor unit 1 to the base plate 260 of the bearing unit 1 by means of bolts 411 or the like (see Figure 2). For this purpose, the stator has a retaining plate 15, which forms, on the one hand, a flange 151 for connection to the stator 12 and, on the other hand, a flange 152 for connection to the base plate 260, as can be seen particularly in Figure 2. In embodiments, the retaining plate 15 can be designed to be flexible in order to improve the dynamic behavior of the drive unit.

[0088] By using a coupling unit 3 with a coupling disc 31, a torque transmission from the rotor 11 to the output shaft 21 can be realized, which on the one hand has a high torsional rigidity and on the other hand has a low rigidity with regard to lateral forces, axial forces and / or bending forces which are introduced into the electric drive unit by a load connected to the output shaft 21, so that introduced forces such as imbalances can be absorbed by the coupling unit 3, so that a decoupling of the rotor 11 from such forces takes place and the precision and symmetry of the air gap 131 between the rotor 11 and the stator 12 is not influenced or only slightly influenced by such forces.

[0089] Figures 4 and 5 show a perspective view of the complete drive unit comprising motor unit 1, bearing unit 2 and coupling unit 3. Reinforcing ribs 27 of the bearing unit 2, which are spaced apart in the circumferential direction and perpendicular to the base plate 260, can be clearly seen in Figure 4. In the oblique view from below in Figure 5, the clutch disc 31 can be seen, which is connected at its radially outer edge 312 to the rotor 11 or at its radially inner edge 311 to the shaft journal 32.

[0090] Figures 6 and 7 show an alternative embodiment of an electric drive unit comprising an electric motor unit 1, a bearing unit 2, and a clutch unit 3. The basic structure is the same as that of the drive unit of Figures 1 to 5, but the motor unit 1 is designed as a radial flux machine with an internal rotor. In particular, it can be provided that the same bearing unit 2 as in Figures 1-5 is used. This is possible due to the modular design of the motor unit 1.

[0091] The motor unit 1 comprises a rotor 11, which is arranged radially inward of a stator 12. The stator 12 comprises a plurality of coils 125. The rotor 11 is arranged inside the stator 12 and rotates about a longitudinal axis which is identical to the rotational and longitudinal axis of the output shaft 21. The rotor 11 comprises a plurality of permanent magnets 16, which are arranged as surface magnets on the outside of the rotor 11. An air gap 132 is formed between the rotor 11 and the stator 12, namely between the permanent magnets 16 of the rotor 11 and the coils 125 of the stator 12. The rotor 11 and the stator 12 are connected to one another via an axially front bearing 141 and an axially rear bearing 142, such that the rotor 11 can rotate within the stator 12.

[0092] The bearing unit 2 comprises the output shaft 21 and the static bearing part 22. The output shaft 21 has a rotational and longitudinal axis (not shown separately) that is identical to the axis of symmetry of the overall arrangement, with the rotational and longitudinal axis defining the axial direction of the drive unit. The static bearing part 22 serves to support the output shaft 21. For this purpose, the bearing unit 2 comprises an axially front bearing 24 and an axially rear bearing 25. The bearings 24, 25 can be designed such that a certain axial play of the output shaft 21 is permitted.

[0093] The static bearing part 22 has a plurality of ribs or stiffeners 27 arranged in the circumferential direction. Furthermore, the static bearing part 22 comprises a base plate 260 extending in the radial direction and a further plate-shaped structure 261, which forms a mechanical interface 26 on its radially outer region for connecting the bearing unit 2 and thus the entire drive unit to a static structure, for example, the airframe of an aircraft.

[0094] The output shaft 21 comprises an axially front end 211, which is coupled to a shaft journal 32 of the coupling unit 3 and is driven via the electric motor unit 1. The output shaft 21 further comprises an axially rear end 212, which forms an interface 23 for connection to a load to be driven. For example, a propeller as a load can be connected to the output shaft 21 via the interface 23. The interface 23 comprises, for example, openings 231 for the implementation of screw connections or bolt connections. The output shaft 21 widens conically between the axially front end 211 and the axially rear end 212. The axial length of the output shaft 21 is greater than the axial height of the motor unit 1 and the coupling unit 3, so that the output shaft 21 protrudes axially relative to the latter.

[0095] The output shaft 21 is pre-assembled in the static bearing part 22, so that the output shaft 21 and bearing part 22 together form the modular bearing unit 2.

[0096] The coupling unit 3 serves to transmit the torque of the rotor 11 of the motor unit 1 to the output shaft 21. The rotor 11 is radially spaced from the output shaft 21. Accordingly, the clutch unit 3 has clutch means extending radially between the rotor 11 and the output shaft 21. In the illustrated embodiment, these clutch means are provided by a clutch disc 31. Alternatively, the clutch means can be formed, for example, by a plurality of radially extending and circumferentially spaced struts or spokes, similar to a bicycle hub.

[0097] The clutch disc 31 is coupled radially outwardly to the rotor 11 and radially inwardly to the output shaft 21. The coupling of the clutch disc 31 to the rotor 11 is achieved via a predefined mechanical interface 42 comprising bolts 421 that non-rotatably connect the radially outer edge 312 (see Figure 7) of the clutch disc 31 to a flange 17 of the rotor 11.

[0098] In this exemplary embodiment, the coupling of the clutch disc 31 to the output shaft 21 also takes place via a shaft journal 32. The radially inner edge 311 (see Figure 7) of the clutch disc 31, which has a central recess, is connected in a rotationally fixed manner to the shaft journal 32 via a mechanical interface 43, which is implemented by bolts 431. The shaft journal 32 comprises an axially projecting region 321, which projects into the axially front end 211 of the output shaft 21 and, due to a positive connection between the shaft journal 32 and the axially front end 211 of the output shaft 21, transmits a torque to the output shaft 21.

[0099] The interface 43 to the shaft journal 32 functionally forms an interface to the output shaft 21, since the output shaft 21 is driven via the shaft journal 32.

[0100] Alternatively, the turbine disk 31 is connected directly to the output shaft 21 without the interposition of a shaft journal 32.

[0101] To connect the motor unit 1 and the bearing unit 2, a mechanical interface 41 is provided, which connects the motor unit 1 to the base plate 260 of the bearing unit 1 by means of bolts 411 or the like. For this purpose, the stator 12 and the base plate 260 each form a flange 153, 262, forming a flange connection.

[0102] By using a clutch unit 3 with a clutch disc 31, a torque transmission from the rotor 11 to the output shaft 21 can be realized, which on the one hand has a high torsional rigidity and on the other hand has a low rigidity with regard to lateral forces, axial forces and / or bending forces introduced into the electric drive unit by a load connected to the output shaft 21, so that introduced forces such as imbalances can be absorbed by the coupling unit 3 and do not influence the precision and symmetry of the air gap 132 between the rotor 11 and the stator 12 or influence it only to a slight extent.

[0103] In both the embodiment of Figures 1 to 5 and the embodiment of Figures 6 and 7, the air gap 131, 132 can have a width of less than 2 mm, in particular less than 1 mm, in particular 0.5 mm. A variation in the width of the air gap 131, 132 can be limited to a maximum of ± 20% of the average air gap width by using a flexible coupling.

[0104] Figures 8 to 13 show embodiments of the invention which are based in principle on the embodiment of Figures 1 to 5 and which further elaborate on the provision of a cooling air channel in the stator for cooling the active components of the stator.

[0105] Figure 8 shows an electric drive unit with a motor unit 1 designed as a transverse flux machine with a rotor 11 and stator 12 and with a bearing unit 2 which comprises an axially arranged, rotatable output shaft 21 and a static bearing part 22 which supports the output shaft 21. The clutch unit 3 explained in Figures 1 to 5 is not shown in Figure 8, but is included accordingly. The reference numerals contained in Figure 8 generally designate the same parts as explained with reference to Figures 1 to 5, unless differences arise from the following description. This applies in particular to the design of the stator 12 as a ring structure with a plurality of ribs 120 which adjoin one another in the circumferential direction and which each form a cooling air channel 121 between them.

[0106] Figure 8 also illustrates the rotational axis 110 of the rotor 11, which is identical to the rotational axis of the output shaft 21 and represents the axis of symmetry of the structure. The rotational axis 110 defines an axial direction x, a radial direction r, and a circumferential direction.

[0107] A difference from Figures 1 to 5 arises from the fact that the motor unit 1 in Figure 8 comprises two rotor-stator assemblies 1110, 1120, which are arranged one behind the other in the axial direction and are firmly connected to one another. Accordingly, the rotor 11 comprises three axially spaced outer walls 111, 112, 114, each of which has or integrates permanent magnets 5, as well as two end-face, radially outer walls 113, 115. The outer walls 111, 112, 114 and the end-face walls 113, 115 form two axially spaced volumes 122 of the two rotor-stator assemblies 1110, 1120, which each contain the active components of the stator 12 of the respective assembly, corresponding to the description of the volume 122 in Figure 1.

[0108] It should be noted that the active components of the stator 12 are held and positioned by the ribs 120. For this purpose, the ribs 120 have retaining projections 123, to which a functional assembly, explained with reference to Figures 11 to 13, is attached, which protrudes into the volume 122 (separately for each rotor-stator assembly 1110, 1120).

[0109] For clarity, the permanent magnets 5 of the rotor are shown only on the right side of Figure 8. They are arranged on the inside of the outer walls 111, 112, 114. The air gap 131 shown in Figure 1 runs between them and the associated stator poles of the aforementioned functional assembly.

[0110] A further difference between Figure 8 and Figures 1 to 5 arises from the fact that Figure 8 shows structures in greater detail that enable the provision of a cooling air flow through the cooling air ducts 121 and the active components of the stator 12 arranged in the volume 122. In general, the transverse flux machine has a first end 1010 facing a load to be driven and a second end 1020 facing away from the load to be driven. In Figure 8, it forms openings 101 at its first end 1010, which allow an air flow 60 to enter the motor unit in an initially primarily axial orientation. This can be supported by a fan 91, which is optional, however. For example, the air flow originates from a propeller driven by the output shaft 21.

[0111] The second end 1020, facing away from the load to be driven, is hermetically sealed to prevent incoming air from immediately leaving the motor unit in the axial direction. A cover plate 102, shown schematically, is provided for this purpose. The cover plate 102 is connected to the stator 12 in Figure 8, but could alternatively be connected to the rotor 11 (or, depending on the design, even be formed by a clutch disc 31 as shown in Figures 1 to 5).

[0112] This ensures that the incoming air flow 60 flows radially outward as air flow 61 through the cooling air ducts 121 and the active components of the stator arranged in the volume 122. The radial air flow 61 can also be optionally supported by fans 92. It should be noted that the end walls 113, 115 of the rotor 11 are provided with radial openings 116, which allow the cooling air flow 61 to be directed into the environment.

[0113] Figure 9 shows a modification of Figure 8, which differs only in the configuration of the cooling air flow. In this respect, reference is made to the explanations for Figure 8. It should also be noted that, to simplify the illustration, the permanent magnets 5 of the rotor 12 are not shown separately in Figure 9, but are of course present in the same way. This also applies to Figure 10.

[0114] In Figure 9, openings 104 are provided in the motor unit at the second end 1020 facing away from the load to be driven, while the first end 1010 facing the load to be driven is hermetically sealed in this case. For this purpose, the openings 101 are closed by structures 103. The openings 104 at the second end are indicated schematically and can, in principle, be realized with a wide variety of openings.

[0115] An incoming airflow 62 from the second end 1020 initially has a primarily axial orientation. This can in turn be supported by an optional axial fan (not separately shown). For example, the airflow 62 originates from a propeller driven by the output shaft 21, whereby the propeller air is deflected behind the rotor 11—as indicated by the arrow 620—and thereby provides an increased dynamic pressure at the end 1020, which causes the airflow 62.

[0116] The air flow 62 then flows radially outward through the cooling air ducts 121 and the active components of the stator arranged in the volume 122 as air flow 63. The radial air flow 61 can also be optionally supported by fans (corresponding to the fans 92 in Figure 8).

[0117] Figure 10 shows a further modification of Figure 8, which differs from Figure 8 only with regard to the formation of the cooling air flow. In this respect, reference is made to the explanations regarding Figure 8.

[0118] In Figure 10, a cooling flow 65 is provided, which extends radially inward through the stator 12. For this purpose, an air flow 64 on the outer circumference of the rotor, which in turn originates, for example, from a propeller, is deflected via guide vanes 117 and guided through the openings 116 in the walls 113, 115 of the rotor 11 into the stator 12 and flows as air flow 65 from radially outside to radially inside through the active components of the stator arranged in the volume 122 and the cooling air channels 121.

[0119] It is provided that, as in Figure 9, the openings 101 at the first end 1010 facing the load are closed, so that the air flow 65, after flowing through the stator 12, is redirected as air flow 66 toward the end 1020. Alternatively, as in Figure 8, the openings at the end 1020 facing away from the load can be closed, in which case the air flow 65 would be redirected toward the end 1010. Fans can again support the desired air flow. It can also be provided that the guide vanes 117 in Figure 10 are replaced by a fan that draws ambient air radially inward.

[0120] Figures 11 to 13 show in greater detail, based on an exemplary embodiment, the active components of the stator, which are arranged in the volume 122 of Figures 8-10. For this purpose, the stator according to Figure 11 comprises a functional unit 9, which can be a modular, prefabricated component. The functional unit 9 extends in the radial direction r and in the circumferential direction (p). It comprises two axially spaced, non-magnetic and non-magnetizable holding plates 93, 94. These have radially inner fastening regions 930, 940, at which the holding plates 93, 94 are connected to a plurality of the ribs 120 of the stator 12. This is achieved, for example, via the holding projections 123 of the ribs 120, see Figures 8 to 10.

[0121] Stator poles 71 extend between the holding plates 93, 94, the entirety of which provides an iron core structure 7 of the stator. The stator poles 71 define a winding space 80 extending in the circumferential direction, in which a coil winding 8 extending in the circumferential direction is arranged. It is provided that an air flow flowing through the cooling air ducts 121 (see Figures 8 to 10) flows radially through the functional units 9 in the region between the two holding plates 91, 92, thereby flowing past the stator poles 71 and the coil winding 8.

[0122] The stator poles 71 are each radially aligned. They each have two radially aligned, circumferentially spaced side surfaces 710, 720, both of which are cooled by a cooling air flow. The coil winding 8 comprises two axially spaced winding packs 81, 82 in a partial winding space 80-1 and two axially spaced winding packs 83, 84 in a partial winding space 80-2, wherein the winding packs 81-84 each represent sections of the coil winding 8 that extend longitudinally in the circumferential direction. As can be seen in Figure 12, the winding packs 81-84 form a coil winding 8, wherein Figure 12 additionally shows a deflected section 85 of the coil winding 8 that connects the winding packs 81-84.

[0123] Two of the winding packages 81, 82 and 83, 84 are spaced apart in the axial direction both from each other and from the holding plates 93, 94, so that cooling air can flow around them on their top and bottom sides. This is illustrated in Figure 13. The functional unit 9 then forms three radially extending and axially spaced cooling air flow channels 67, 68, 69 for cooling the winding packages 81, 82 and 83, 84, with a cooling air flow channel 67 running adjacent to the upper holding plate 93, a cooling air flow channel 68 running in the area between the winding packages 81, 83 and 82, 84, and a cooling air flow channel 69 running adjacent to the lower holding plate 94. Dividing the winding into axially spaced winding packs 81-84 increases the cooling surface of the winding. Other design variants may also include more than two axially spaced winding packs.

[0124] Two winding packages 81, 82 and 83, 84 can each be fixed in the winding space 80-1, 80-2 by a fixing material 86, whereby the fixing material, however, extends only slightly in the circumferential direction (and is thus plate-shaped) in order not to impair cooling by the cooling air flow.

[0125] Referring again to Figure 11, a special arrangement of the stator poles 71 is provided to realize the partial winding spaces 80-1, 80-2. Thus, the stator poles 71 are arranged in four circumferential rows 71-1, 71-2, 71-3, 71-4, with two of the circumferential rows 71-1, 71-2 and 71-3, 71-4 being assigned to one another and forming a partial winding space 80-1, 80-2. Furthermore, it is provided that the stator poles 71 of each of two mutually assigned circumferential rows 71-1, 71-2 and 71-3, 71-4 are arranged offset from one another in the circumferential direction.

[0126] Furthermore, the stator poles 71 are curved. They are bent, for example, in a C-shape. The stator poles 71 of the respective radially inner circumferential rows 71-1, 71-3 are concavely curved when viewed from the radial outside, and the stator poles 71 of the respective radially outer circumferential rows 71-2, 71-4 are convexly curved when viewed from the radial outside, so that their mutually facing sections jointly define the partial winding spaces 80-1, 80-2. The stator poles 71 of the two rows delimit the partial winding spaces transversely to the circumferential direction. For this purpose, the stator poles 71 are arranged in the mutually assigned circumferential rows 71-1, 71-2 and 71-3, 71-4 in the reverse orientation.

[0127] Furthermore, it is provided that the ends of the stator poles 71 form pole heads 72, 73 (upper pole heads 72 and lower pole heads 73). The pole heads 72, 73 border the permanent magnets 5 of Figure 8 and are separated from them only by an air gap (corresponding to the air gap 131 of Figure 1). For this purpose, it is provided that the pole heads 72, 73 are each arranged in one of the holding plates 93, 94 and are flush with their outer sides 931, 941. Accordingly, in Figures 11 to 13, the upper pole heads 72 can be seen in the plane of the outer side 931 of the upper holding plate 93.

[0128] In each rotor-stator assembly 1110, 1120 of Figures 8 to 10, several functional units 9 are provided, which are connected to one another in the circumferential direction. For example, three functional units 9 are provided per rotor-stator assembly 1110, 1120, with the coil winding of each functional unit being supplied with one phase of a three-phase alternating voltage.

[0129] Please note that cooling of the active components of the stator has been described using air as the cooling medium. However, this is only an example. Gases other than air can be used as the cooling medium. A liquid can also be used as the cooling medium. The cooling fluid can therefore be either a liquid or a gas, such as air.

[0130] It should also be noted that a radial air flow in the stator of a transverse flux machine has been explained using a transverse flux machine integrated into an electric drive unit according to Figures 1 to 5. However, this is only to be understood as an example. The principles of the present invention apply regardless of the particular drive unit into which the transverse flux machine is integrated.

[0131] It should also be noted that in the described embodiments, the air gap between the stator and rotor extends in a radial direction (with an axial normal vector of the air gap surfaces). Alternatively, the cooling concept can be designed such that the air gap extends axially (with a radial normal vector of the air gap surfaces). The principles of the present invention also apply to such a cooling concept.

[0132] It is understood that the invention is not limited to the embodiments described above, and various modifications and improvements may be made without departing from the concepts described herein. It is further understood that any of the described features may be used separately or in combination with any other features, provided they are not mutually exclusive. The disclosure extends to and encompasses all combinations and subcombinations of one or more features described herein. Where ranges are defined, these include all values ​​within these ranges, as well as all subranges that fall within a range.

Claims

Patent claims 1. Transverse flux machine comprising: a rotor (11) equipped with permanent magnets (5) and having an axis of rotation (110) defining an axial direction, a radial direction and a circumferential direction, a stator (12), active components (7, 8) of the stator (12) comprising a coil winding (8), - wherein the stator (12) is designed as a ring structure with a plurality of ribs (120) which adjoin each other in the circumferential direction and which each form a cooling air channel (121) between them, wherein the ribs (120) are provided and designed to hold and position the active components (7, 8) of the stator (12).

2. Transverse flux machine according to claim 1, characterized in that the rotor (11) is designed as an externally running rotor.

3. Transverse flux machine according to claim 1 or 2, characterized in that the rotor (11) has axially spaced outer walls (111 , 112, 114) which each have or integrate permanent magnets (5), and an end wall (113, 115) which is provided with radial openings (116) which are designed and configured to direct cooling fluid flowing through the cooling air channels (121) of the stator (12) into the environment or from the environment towards the cooling air channels (121).

4. Transverse flux machine according to claim 3, characterized in that the active components (7, 8) of the stator (12), which are held by the ribs (120) of the stator (12), are arranged in a volume (122) bounded by the outer walls (111 , 112, 114) and the end wall (113, 115) of the rotor (11).

5. Transverse flux machine according to one of the preceding claims, characterized in that the rotor (11) and the stator (12) form an air gap (131) extending in a radial direction and rotating circumferentially. A transverse flux machine according to claim 5, insofar as it relates back to claim 4, characterized in that an air gap (131) between the active components (7) of the stator (12) and the permanent magnets (5) of the rotor (11) extends on the inside adjacent to the outer walls (111, 112). A transverse flux machine according to any one of the preceding claims, characterized in that the active components (7, 8) of the stator (12) are arranged and configured such that a fluid flow (61, 63, 65) flowing radially through the cooling air channels (121) flows past the surfaces of the active components (7, 8) and cools them.Transverse flux machine according to one of the preceding claims, characterized in that the active components (7, 8) of the stator (12) are arranged in functional units (9) which each extend in a radial direction and over a circumferential segment in the circumferential direction and which each are held by a plurality of the ribs (120), wherein the functional units (9) each comprise:. - two axially spaced, non-magnetic and non-magnetizable retaining plates (93, 94), - stator poles (71) extending between the retaining plates (93, 94), defining a circumferentially extending winding space (80) in which a circumferentially extending coil winding (8) is arranged, - wherein a fluid flow passing through the cooling air channels (121) flows radially through the functional units (9) between the two mounting plates (91, 92) and flows past the stator poles (71) and the coil winding (8). Transverse flux machine according to claim 8, characterized in that the coil winding (8) has at least two axially spaced winding packages (81, 82; 83, 84). Transverse flux machine according to claim 8 or 9, characterized in that the coil winding (8) is axially spaced from the mounting plates (93, 94). Transverse flux machine according to claims 9 and 10, characterized in that the coil winding (8) has at least two axially spaced winding packages (81, 82; 83, 84) which are spaced axially from each other and from the retaining plates (93, 94), wherein the functional unit (9) has at least three forms radially extending and axially spaced cooling air flow channels (67, 68, 69) for cooling the winding packages (81 , 82; 83, 84).

12. Transverse flux machine according to one of claims 8 to 11, characterized in that the stator poles (71) are each radially oriented and have radially oriented, circumferentially spaced side surfaces (710, 720).

13. Transverse flux machine according to one of claims 8 to 12, characterized in that the stator poles (71) are each curved and arranged in at least two mutually associated circumferential rows (71-1, 72-2), wherein the at least two circumferential rows (71-1, 71-2) are radially spaced apart, the stator poles (71) of the two circumferential rows (71-1, 71-2) are each arranged offset from one another in the circumferential direction, the stator poles (71) of the radially inner circumferential row (71-1) are concavely curved when viewed from the radial outside, and the stator poles (71) of the radially outer circumferential row (71-1) are convexly curved when viewed from the radial outside, such that their mutually facing sections jointly define the winding space (80) or a partial winding space (80-1, 80-2), wherein they define the winding space (80) transversely to the circumferential direction limit, and the ends of the stator poles (71) form pole heads (72, 73) adjacent to the rotor (11), each of which is mounted in one of the retaining plates (93,94) are ordered., 14. Transverse flux machine according to claim 13, characterized in that the stator poles (71) are arranged in at least four circumferential rows (71-1, 71-2, 71-3, 71-4), wherein two of the circumferential rows (71-1, 71-2; 71-3, 71-4) are assigned to each other and form a partial winding space (80-1, 80-2), wherein the partial winding spaces (80-1, 80-2) extend radially apart in the circumferential direction, and wherein sections (81, 82; 83, 84) of the coil winding (8) extending in the circumferential direction are arranged in the partial winding spaces (80-1, 80-2).

15. Transverse flux machine according to one of claims 8 to 14, characterized in that the coil winding (8) is fixed in sections by a fixing material (86) in the winding space (80).

16. Transverse flux machine according to one of the preceding claims, characterized in that the transverse flux machine is a load to be driven a first end (1010) facing the load to be driven and a second end (1020) facing away from the load to be driven, and that the transverse flux machine forms openings (101 , 104) at its first end (1010) or at its second end (1020) which in operation allow a fluid flow (60-66) which flows in the radial direction or against the radial direction through the cooling air channels (121) and the active components (7, 8) of the stator (12).

17. Transverse flux machine according to claim 16, characterized in that the openings (101) are formed at the first end (1010) and the second end (1020) is tightly closed, wherein the transverse flux machine is configured to direct cooling fluid flowing in through the openings (101) radially outwards through the cooling air channels (121) and the active components (7, 8) of the stator (12).

18. Transverse flux machine according to claim 16, characterized in that the openings (104) are formed at the second end (1020) and the first end (1010) is tightly closed, wherein the transverse flux machine is configured to direct cooling fluid flowing in through the openings (104) radially outwards through the cooling air channels (121) and the active components (7, 8) of the stator (12).

19. Transverse flux machine according to claim 16, characterized in that the openings (101 , 104) are formed at the first end (1010) or at the second end (1020), wherein the transverse flux machine is configured to guide cooling fluid obtained from the outside of the transverse flux machine from radially outside to radially inside through the active components (7, 8) and the cooling air channels (121).

20. Transverse flux machine according to claim 19, characterized in that the transverse flux machine has guiding elements (117) on its outer side, which are designed to deflect axially flowing cooling fluid (64) through openings (116) in the direction of the active components (7, 8) of the stator (12) and the cooling air channels (121).

21. Transverse flow machine according to one of claims 16 to 20, characterized by at least one fan (91 , 92) which directs the fluid flow (60-66) in a desired direction.

22. Electric drive unit comprising: an electric motor unit (1) configured as a transverse flux machine according to claim 1, a bearing unit (2) with o an axially arranged, rotatable output shaft (21), and o a static bearing part (22) that supports the output shaft (21), o wherein the output shaft (21) has an interface (23) for connection with a driven load, and - a coupling unit (3) that provides a torque transmission from the rotor (11) to the output shaft (21), wherein the rotor (11) is arranged radially spaced from the output shaft (21) and the coupling unit (3) comprises coupling means (31) that extend in a radial direction between the rotor (11) and the output shaft (21).

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