Stator for a radial-flow double rotor machine, radial-flow double rotor machine, and method for producing a stator

Abstract

The invention relates to a stator for a radial-flow double rotor machine, in particular for a wheel hub motor, having: a stator core which has a first axial portion and a second axial portion adjoining the first axial portion; and a winding which is placed in the stator core and is designed to be self-supporting in order to support the torque of the stator and which protrudes beyond the first axial portion at at least one axial end, the second axial portion being provided as a support device which is designed to interlockingly engage with the winding at the at least one axial end in order to support the torque. The invention further relates to a radial-flow double rotor machine having such a stator and to a method for producing the stator.

Description

[0001] Stator for a radial flux twin-rotor machine, radial flux twin-rotor machine, method for manufacturing a stator. SCOPE OF INVENTION The present invention relates to a stator for a radial flux twin-rotor machine, in particular for a wheel hub motor, a radial flux twin-rotor machine, and a method for manufacturing a stator. TECHNICAL BACKGROUND Electric machines with one stator and two rotors rigidly connected to each other, so-called twin-rotor machines (also referred to as multiple rotors, dual rotors, etc.), can increase both the torque density and the efficiency of electric drives compared to conventional electric machines with only one rotor. This is because, particularly in so-called "yokeless" designs, no magnetic return path is required in the stator, and this significantly reduces remagnetization losses.Furthermore, with two rotors, there is generally more space available for the field-exciting magnets (in permanent magnet synchronous machines, PSM) or the conductor material (in induction machines, IM, or electrically excited synchronous machines, ESM). According to the orientation of the magnetic field lines in the air gap, such machines can be divided into two groups: axial flux-carrying (field lines parallel to the axis of rotation, so-called axial flux machines) on the one hand, and radial flux-carrying (field lines in a radial direction in the air gap, so-called radial flux machines) on the other. A radial flux twin-rotor machine is described, for example, in DE 102021 003 942 A1. It is characterized by a high torque and power density. For radial flux twin-rotor machines, established and mass-production-ready manufacturing processes can, in principle, be used for the winding and laminated core.However, a certain challenge lies in supporting the torque generated in the stator core. The internally and externally rotating parts necessitate that the stator lamination stack cannot be mounted in a stationary housing (e.g., pressed, screwed, or glued) as is otherwise customary. The torque is therefore directed to the axial ends of the stator lamination stack and the stator winding, respectively, and supported there by a separate support structure. SUMMARY OF THE INVENTION Against this background, the present invention aims to provide an improved stator for a radial flux twin-rotor machine, an improved radial flux twin-rotor machine, and an improved method for manufacturing a stator for a radial flux twin-rotor machine, all of which exhibit reduced manufacturing costs and increased machine efficiency.According to the invention, this problem is solved by a stator with the features of claim 1 and / or by a radial flux twin-rotor machine with the features of claim 16 and / or by a method for manufacturing a stator for a radial flux twin-rotor machine with the features of claim 18.Accordingly, the following is provided: - A stator for a radial flux twin-rotor machine, in particular for a wheel hub motor, comprising: a stator core having a first axial section and a second axial section adjoining the first axial section; a winding placed in the stator core, which is designed to be self-supporting for torque support of the stator and projects beyond the first axial section at at least one axial end, wherein the second axial section is provided as a support device, in particular integrated in the stator core, which is designed to engage with the winding at the at least one axial end, in particular in a positive-locking manner, for torque support.- A radial flux double rotor machine, in particular for a wheel hub drive, comprising: a mechanically fixed base; a stator according to the invention, wherein the second axial section engages with at least one axial end of the winding for torque support, in particular in a positive-locking manner, and the second axial section is supported at the base; a first rotor arranged radially inside the stator core; and a second rotor arranged radially outside the stator core.- A method for manufacturing a stator for a radial flux twin-rotor machine, in particular a stator according to the invention, comprising the steps of: providing a stator core having a first axial section and a second axial section, each with radially outer stator slots describing a helix and radially inner stator slots describing a helix with an opposite winding direction; inserting individual conductor bars following the helix lines through the inner and outer stator slots, and connecting the conductor bars inserted into the inner and outer stator slots at the conductor bar ends to form conductor loops, wherein the second axial section is provided as a support device, in particular integrated in the stator core, which is designed for engagement with the winding at at least one axial end, in particular positive locking, to support torque.The underlying insight of the present invention is that in radial flux twin-rotor machines, torque arises as an interfacial force between the winding, the stator core, and the air gap. This torque is transmitted to the conductor bars, which absorb it and carry it to the winding end. From the winding end, it is transmitted to the support structure. The stator core serves to guide the magnetic field. Axial torque transmission is not possible due to the layered structure of the stator core, as very little force can be transmitted between the layers. Furthermore, the winding head support in the stator is a component with high manufacturing complexity, and the winding and winding head exhibit very low inductance, resulting in high current ripple, which is associated with high losses and reduced machine efficiency.The underlying idea of ​​the present invention is to achieve a guidance of the force flow in the stator core by designing the stator with a first axial section that accommodates the windings and a subsequent second axial section that engages with the axial end of the winding and serves for torque support. The force flow is guided via the first axial section and the winding into the second axial section, which acts as a support element, and the torque support is provided within the stator core itself. In particular, the engagement with the winding is positive-locking. This eliminates the need for torque support via a separate support element arranged axially offset from the stator core. The stator core, which is laminated, i.e.,Since the stator is designed as a laminated core and accommodates the winding while simultaneously serving as a torque support, it increases the leakage flux and thus the machine inductance. This results in lower current ripple, thereby increasing machine efficiency. The stator designed in this way can then be combined with various inner and outer rotors known to those skilled in the art to form an electric machine according to the invention. These include, for example, permanent magnet rotors with surface magnets and / or buried magnets, squirrel-cage rotors, or electrically excited rotors. Hybrid versions with different rotor types in the inner and outer rotors can also be provided. One possible embodiment involves the rotors being made of solid soft magnetic material and featuring surface-mounted permanent magnets.The low upper field spectrum of the winding variants described here, and the distance between the solid material and the air gap ensured by the magnets, prevents the formation of unacceptably large losses due to eddy currents in the rotors. In this design, comparatively high efficiencies can be advantageously achieved, while the rotors can still be manufactured very cost-effectively. To produce a radial flux twin-rotor machine, the support structure integrated into the stator core and provided by the second axial section of the stator core can be firmly connected to a base as part of the electrical machine using a suitable method. One possible design provides recesses, such as through-holes, for friction-fit fasteners, such as screws. However, alternatively or additionally, positive-locking fasteners and / or a material-bonded connection would also be conceivable.In particular, the present invention is especially advantageous for use in a wheel hub motor, preferably for a motor vehicle. Due to the functional integration of the design according to the invention, the mass of a radial flux twin-rotor machine can be reduced and the torque density increased, which, particularly in the case of wheel hub motors, advantageously means a reduction in unsprung mass. Furthermore, according to the invention, a comparatively short axial length can be achieved with a comparatively large diameter, which is particularly advantageous inside the wheel with regard to torque support and installation space. Advantageous embodiments and further developments will become apparent from the dependent claims and from the description with reference to the figures of the drawing.According to one embodiment, the winding is designed to be torsionally stiff such that a torque acting on the stator core during the operation of a radial flux twin-rotor machine can be supported, in particular completely, by the torsionally stiff winding in the second axial section. The winding is formed, in particular, from conductor bars connected to one another, especially in a truss-like manner, wherein the winding has a radially inner layer of helically arranged conductor bars and a radially outer layer of oppositely helically arranged conductor bars. Preferably, the radially inner layer and the radially outer layer of the winding each have the thickness of a single conductor bar, wherein the conductor bars are twisted according to the helical path such that the cross-section of a conductor bar is the same at every point along the conductor, relative to a radial axis of the cross-section.In this way, the winding forms a truss structure exhibiting high torsional stiffness. The conductor bars of the inner layer and the conductor bars of the outer layer each describe a helix whose winding directions or pitches are opposite to each other. The angle swept by the helix between the beginning and end of a conductor bar, relative to the central axis of the stator, is specifically designed such that, in a radial flux twin-rotor machine, one conductor loop is formed per pole of the rotors. The required swept angle can thus be calculated from the quotient of one complete revolution (2n or 360°) and twice the number of pole pairs, p. Because the radially inner layer and the radially outer layer of the winding each have the thickness of a single conductor bar, each phase of the winding is formed with the cross-section of a single conductor bar.Such a winding configuration according to the invention is made possible, among other things, by the special design of the radial flux double-rotor machine, which, by means of its magnetic symmetry, prevents the current displacement to the surface that otherwise occurs in conductors. In this way, comparatively thick conductor cross-sections are possible, and a relatively uniform current distribution across the cross-section is still achieved. For example, the thickness of the conductor bars can be in the range of several millimeters. In particular, these can be square-profile bars with edge lengths of several millimeters, for example in the range of 2 mm to 6 mm, and especially in the range of 3 mm to 5 mm. Other cross-sectional shapes are also possible.The conductor bars are twisted according to their helical shape, ensuring that the cross-section of each conductor bar is uniform along its radial axis. Specifically, this involves a twist of the conductor bar, particularly a non-circular one, around the central axis of the stator or machine. Depending on the helical shape, the conductor bars may also be bent. The inner and outer layers are interlocked, meaning they are twisted, rotated, and, if necessary, bent in opposite directions. This design ensures that, from a mechanical perspective, the conductor bar is ideally aligned with the stator core for power transmission, resulting in a uniform load distribution along its length.In the resulting truss structure, the conductors advantageously absorb predominantly tensile and compressive stresses when subjected to tangential force. This avoids load peaks and deformations of the conductor bars. In particular, compared to a design with axially parallel, straight conductors, the mechanical stresses can thus be significantly reduced. The conductor bars of the radially inner and outer layers belonging to the same phase of the winding are connected to each other at their ends, in particular via a radially arranged conductor bar section and / or by means of a material-bonded connection. This creates not only a conductor loop but also a torsionally rigid, truss-like structure, so that when an axially accessible winding end is fixed, a high torque can be absorbed by the winding without causing unacceptably large deformations and / or stress states.Thus, the self-supporting design of the winding is made possible solely by the winding material, for example, copper, without the need for additional support materials or elements. This results in improved power transmission and a more compact design with reduced manufacturing effort. According to one embodiment, the stator core comprises a stator lamination stack forming the first and second axial sections, each with stator slots arranged helically according to the winding path. A single conductor bar is arranged in each stator slot of the stator lamination stack, and the stator slots in the first and second axial sections may be identical or different. The winding, or the self-supporting truss structure formed by it, is thus embedded in both axial sections of the stator lamination stack.Analogous to the conductor bars of the winding, the stator slots therefore change their tangential position depending on the axial position, resulting in a helical shape. The direction of the change in position follows the conductor bars; that is, the centerline of the radially outer slots and the radially inner slots each describe a helix, but with opposite winding directions. According to one embodiment, the stator slots in the second axial section are configured as either open or closed slots. The configuration of the slots in the second axial section, which has a load-bearing and torque-supporting function, can be selected independently of the configuration of the slots in the first axial section, which is designed to generate torque and conduct the main current. Thus, closed slots can be used in the second axial section, and the conductor bars or...Grooves completely enclosing the conductor ends are provided, while open grooves for guiding the conductors are provided in the first axial section. Alternatively, the grooves in the second axial section can have a reduced opening width compared to the grooves in the first axial section to achieve an optimal configuration of the entire lamination stack, enabling the inventive purpose of integrated torque support via the stator core. The self-supporting winding is therefore arranged without support in the first axial section of the stator core, while support is provided in the second axial section.According to one embodiment, the recesses in the stator laminations of the first axial section and those in the stator laminations of the second axial section, which are intended to form the stator slots, are identical. The helical orientation of the stator slots in the first and second axial sections is achieved by stacking the respective stator laminations in a twisted arrangement relative to each other. In this way, the stator lamination stack can be manufactured very economically, since the same die can be used for all the parallel or stacked stator laminations. Accordingly, two adjacent stator laminations are slightly twisted relative to each other by a predetermined angle about the central axis, so that the recesses are arranged in an overlap that corresponds to the helical orientation.According to one embodiment, the stator lamination stack comprises, with respect to the first and second axial sections, an inner sub-stack with radially inner stator slots and an outer sub-stack with radially outer stator slots, wherein the stator laminations of the respective inner sub-stack and the stator laminations of the respective outer sub-stack are designed with the same geometry, and wherein the stator laminations of the respective inner sub-stack and the stator laminations of the respective outer sub-stack are stacked with opposite twists relative to each other. In this way, the opposite helix angles of the stator slots can be realized with minimal manufacturing effort. Nevertheless, a very economical manufacturing method is still possible, since the same stamping die can be used for all parallel or stacked stator laminations of the inner sub-stack, and for all parallel or stacked stator laminations of the outer sub-stack, the same die can be used.The same die can be used for the stacked stator laminations of the outer sub-package. Accordingly, two adjacent stator laminations of the inner sub-package are slightly rotated relative to each other in a first direction by a predetermined angle around the central axis, and two adjacent stator laminations of the outer sub-package are slightly rotated relative to each other in a second, opposite direction by a predetermined angle around the central axis. In this way, the recesses of the stator laminations of the inner sub-package and the recesses of the stator laminations of the outer sub-package are arranged in opposite overlap to each other, which corresponds to the opposite helix direction. According to one embodiment, the stator laminations are configured differently with respect to the first and second axial sections, with recesses provided for forming the stator grooves in the first axial section and in the second axial section.The helical shape of the stator slots is achieved by varying the spacing of the recesses in the individual stator laminations and thus in their respective axial sections. In this way, a custom-fit stator lamination shape is produced for each position of a stator lamination within the stack, and the individual geometries can also be repeated within the stack. In this case, production can be carried out, for example, using a beam cutting process, particularly laser beam cutting, which offers greater flexibility in terms of shape compared to a stamping process. Flexible stamping dies with variable geometries are also conceivable, or, for very high production volumes, several individual stamping dies for each of the different stator lamination shapes.According to a further embodiment, the recesses for radially inner and radially outer stator slots in the first axial section and the second axial section are each integrated into a common stator lamination, with the opposing helical orientation of the radially inner and radially outer stator slots being achieved by a continuous displacement of the inner and outer stator slots of the first and second axial sections relative to each other from stator lamination to stator lamination. Here, too, a suitably shaped stator lamination is produced for each position of a stator lamination within the stack, and the individual geometries can also be repeated within the stack. Here, too, flexible cutting processes, such as laser beam cutting, are used for manufacturing.The single-piece manufacturing of the inner and outer recesses advantageously reduces the number of parts. According to one embodiment, the respective stator laminations of the first axial section and the second axial section have straight, in particular stamped, edges, with the width of the recesses provided for the respective stator slots being greater than the width of the conductor bars by an amount predetermined by the pitch of the helical shape and the lamination thickness. The reduced clear width or continuous width of the stator slots, resulting from the offset between the recesses of the stator laminations, thus essentially corresponds to the width of a conductor bar. In practice, the continuous clear width of the stator slot is provided to be slightly larger than the width of the conductor bar to ensure the necessary clearance for inserting the conductor bars.The edge of a stator slot thus defines a stepped shape with the respective lamination thickness as steps, against which the conductor bar is uniformly supported. In this way, torque support is achieved uniformly across the entire thickness of the stator lamination stack or across the entire length of the conductor bars accommodated within the stator lamination stack. This also allows for the simple implementation of different slot configurations in the first and second axial sections. According to one embodiment, the second axial section has a radial extension compared to the first axial section, whereby the radial extension is formed by the stator core or can be designed as a support element that engages with the stator core. In both cases, torque support takes place in the stator core, i.e., in the winding head or...The second axial section, however, is not supported by a support element arranged axially offset from the stator core, which is designed for positive engagement with the winding at at least one axial end of the winding. The torque support is therefore shifted axially inwards, i.e., into the stator core. This laminated design of the support element increases leakage flux and thus the machine inductance. This, in turn, reduces current ripple on the stator core and therefore increases machine efficiency. The support element is inserted into the stator core, i.e., the second axial section, and is not arranged axially offset outwards, i.e., outside the stator core, and supports the torque support via the second axial section.According to one embodiment, the support element is formed from sheet metal or from a solid material, in particular a thermally conductive solid material, especially a metal, preferably an aluminum alloy, and advantageously supports the previously described positive effects regarding stray flux. According to one embodiment, the support element can be positively connected to the second axial section, in particular by an interference fit or by a material bond, in particular by adhesive bonding, and is preferably arranged axially flush with the second axial section. This allows for a compact design with simultaneously improved torque support in a simple manner. According to one embodiment, the support element is formed by a first radially inner sub-element that can be inserted into the second axial section and a second radially outer sub-element that can be slid onto the first axial section.In one embodiment, the first radially inner sub-element, which can be inserted into the second axial section, and the second radially outer sub-element, which can be slid onto the first axial section, can additionally have support grooves on their respective circumferences that engage positively with the conductor bars. In each case, a more compact design is achieved while simultaneously offering advantages with regard to torque support. According to a further embodiment of the radial flux double-rotor machine according to the invention, the second axial section is connected to a support element that radially extends the second axial section and is either laminated or made of a thermally conductive material, in particular a metal, preferably an aluminum alloy. The support element is supported at the base. Here, the support element serves for a positive connection with the base, while the torque support is provided via the stator core, i.e.,the second axial section is reached. This allows for a more compact and simpler design of the radial flux twin-rotor machine in terms of manufacturing. According to a further embodiment of the method for manufacturing a stator, the step of providing the stator core comprises the production of a stator lamination stack, wherein individual stator laminations of the first axial section and the second axial section, which have recesses for forming stator grooves, are stacked twisted relative to each other. In this way, the stator lamination stack can be manufactured very economically, since the same die can be used for all parallel or stacked stator laminations.Accordingly, two adjacent stator laminations are slightly rotated relative to each other by a predetermined angle around the central axis, so that the recesses are arranged in an overlap that corresponds to the helical path. The individual stator laminations for the first and second axial sections with such a geometry are advantageously manufactured by stamping or laser cutting of individual laminations from electrical steel.According to a further embodiment of the stator manufacturing method, the stator lamination stack comprises an inner sub-stack and an outer sub-stack with respect to the first and second axial sections, wherein in the first and second axial sections, all stator laminations of the inner sub-stack and all stator laminations of the outer sub-stack are formed with the same geometry, and wherein the stator laminations of the inner sub-stack are stacked in opposite directions to form the inner stator slots, and the stator laminations of the outer sub-stack are stacked in opposite directions to form the outer stator slots. In this case, all laminations of the inner and outer stacks in the first and second axial sections can be formed with the same geometry, making the manufacturing process very economical.Regarding the first and second axial sections, the same die can be used for all parallel or stacked stator laminations of the inner sub-package and for all parallel or stacked stator laminations of the outer sub-package. Two adjacent stator laminations of the inner sub-package are slightly rotated relative to each other by a predetermined angle around the central axis in a first direction, and two adjacent stator laminations of the outer sub-package are slightly rotated relative to each other by a predetermined angle around the central axis in a second direction. In this way, the recesses of the stator laminations of the inner sub-package and the recesses of the stator laminations of the outer sub-package are arranged in opposite overlap to each other, which corresponds to the opposite helical path. In this way, the opposite helical paths of the stator slots can be realized with minimal manufacturing effort.According to one embodiment of the stator manufacturing method, the stator lamination stack has a plurality of differently shaped stator laminations in the first axial section and in the second axial section, wherein the recesses for the inner and outer stator slots are each integrated in a common stator lamination, and wherein the pitch of the helix is ​​achieved by a continuous displacement of the inner and outer stator slots relative to each other from stator lamination to stator lamination, in particular with a flexible punching or laser beam cutting process. In this process, inner and outer stator slots are integrated into a single stator lamination (lamella), and the helical orientation of the stator slots is achieved in each individual lamination by a continuous displacement of the recesses relative to each other during the cutting process, for example, by means of a flexible punching process or a laser beam cutting process.This has the advantage that fewer parts mean fewer manufacturing steps are necessary, and the resulting stator lamination or the entire stator core exhibits higher mechanical strength. According to one embodiment of the method, the process further comprises the step of axially flush arranging a support element that radially extends the second axial section within the second axial section. The axially flush arranging of the support element preferably comprises the axially flush arranging of a radially inner sub-element and a radially outer sub-element. According to another embodiment of the method, the step of axially flush arranging the support element comprises a positive-locking connection, in particular by forming an interference fit or a force-locking connection, especially by bonding the support element or the sub-elements to the second axial section and thus to the stator core.According to one aspect, a stator manufactured in this way can also be used to carry out a method for manufacturing a radial flux twin-rotor machine, with the further steps of: providing a mechanically fixed base and attaching the second axial section of the stator core, which provides a support structure, to the base. The above embodiments and further developments can be combined with each other as appropriate. In particular, all features of the stator can be transferred to the method for manufacturing a stator, and vice versa. Furthermore, all features of the stator can be transferred to a corresponding radial flux twin-rotor machine, as well as to a vehicle axle with such a radial flux twin-rotor machine and / or a vehicle with such a vehicle axle. The above embodiments and further developments can be combined with each other as appropriate.Further possible embodiments, developments, and implementations of the invention also include combinations of features of the invention described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention. DESCRIPTION OF THE DRAWING The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing. These show: Fig. 1 an exploded view of a stator according to one embodiment; Fig. 2 an exploded view of a partially assembled stator of a radial flux twin-rotor machine according to another embodiment; Fig. 3 a perspective view of the stator of a radial flux twin-rotor machine according to Fig. 2 in the assembled state; Fig.Figure 4 shows an exploded view of a stator according to a further embodiment; Figure 5 shows a perspective view of a winding; Figure 6 shows a top view of a winding; and Figure 7 shows a flowchart of a method for manufacturing a stator. The accompanying figures are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain the principles and concepts of the invention. Other embodiments and many of the advantages mentioned will become apparent with reference to the drawings. The elements of the drawings are not necessarily shown to scale. In the figures of the drawing, identical, functionally equivalent, and similarly acting elements, features, and components are each provided with the same reference numerals, unless otherwise stated. DESCRIPTION OF EXAMPLES OF EMBODIMENTS Fig.Figure 1 shows an exploded view of a stator 1 according to one embodiment. The stator 1 has a winding 3, a stator core 2 with a first axial section 5 and a second axial section 7 adjoining it axially, and a support element 11 comprising a first radially inner sub-element 12 and a second radially outer sub-element 13, where an advantageous exemplary embodiment of these components is shown in more detail in perspective. The winding 3 is constructed from an inner and outer layer 14, 15 with several conductor bars 6 connected to each other in a truss-like manner. The conductor bars 6 in the inner and outer layers 14, 15 are arranged in opposite directions in a helical pattern and are bent towards each other at the conductor bar ends 16, 17. To connect the inner and outer layers 14, 15, the conductor rod ends 16, 17 are each welded together and thus radially coupled by a material bond.The thickness of the inner and outer layers 14, 15 each corresponds to the thickness of a conductor bar 6. This means that the winding 3 is formed by a single conductor layer with a comparatively large cross-section, forming the conductor loop, in the form of a conductor bar 6. Due to the truss structure formed by the conductor bars 6, the winding 3 is torsionally rigid and thus self-supporting for torque resistance. The conductor bars 6 accordingly form wave-shaped winding strands and can be connected to a rotating field-generating winding 3 of any number of strands by appropriate connections known to those skilled in the art and therefore not described further, such as delta connection, star connection, or the like. In the illustrated embodiment, the stator core 2 is formed from an inner sub-package 23 and an outer sub-package 24.The stator core 2 comprises a first axial section 5, which is designed in the respective sub-assemblies 23, 24 according to the arrangement and configuration of the stator laminations 21, 22 and is designed to generate torque and conduct the main flux, and a second axial section 7, which is designed to support torque and in which the axial ends 4 of the winding 3 are received for torque support. The second axial section 7 has a radial extension with stator slots 19, 20 that are larger than those of the first axial section and in which the axial conductor bar ends 16, 17 are received. This achieves torque support through the second axial section 7 of the stator core 2. Through this functional integration, the stator core 2 is designed to generate torque and conduct the main flux in the first axial section 5 and to support torque in the second axial section 7.Associated with the stator core 2 is a support element 11 that radially extends the second axial section 7 and supports the stator lamination stack 18. The support element 11 is, by way of example, composed of two components: a radially inner and a radially outer sub-element 12, 13. For the assembly of the stator 1, the winding 3 and the stator core 2 are arranged nested within each other, and then the support element 11, or the two sub-elements 12, 13, are inserted flush with the axial end 4 of the stator core 2. The support element 11 can be inserted, for example, by an interference fit or by adhesive bonding. After assembly, the components are aligned coaxially with each other along the common central axis. The two-part support element 11 shown here is arranged axially flush with the other components and closes off the stator core 2.The two-part stator core 2 shown here as an example is formed with two stator lamination stacks 18 twisted helically relative to each other. In other embodiments, the stator core 2 can also be made in one piece or with more than two parts. Fig. 2 shows an exploded view of a stator 1 for a radial flux twin-rotor machine according to another embodiment. The stator 1 here has essentially the same components as described with reference to Fig. 1. Therefore, identical elements are not described again. The support element 11 shown on the right is made in two parts and has a sub-element 12 for the radially inner arrangement in the stator core 2 and a sub-element 13 for the radially outer arrangement on the stator core 2.The inner sub-element 12 and the outer sub-element 13 are each provided with several bores 9 around their circumference for attachment to a base, for example, the housing of a radial flux twin-rotor machine. The bores 9 are shown here as an example, evenly distributed around the circumference along a circle of holes. The individual bores 9 are located slightly outside the main body of the sub-elements 12, 13 and therefore form a star shape on the circumference opposite the winding 3. Of course, other distributions of the bores 9 as well as other types of fastening means for connecting to the base are conceivable. Fig. 3 shows a perspective view of a stator 1 of a radial flux twin-rotor machine in its assembled state.The support element 11 is attached via the bores 9, for example, in a machine housing (not shown) as a base, and thus transmits the torque from the torque-supporting second axial section 7 of the stator core 2 to the mechanically fixed part of the radial flux twin-rotor machine. In this way, the torque generated by the radial flux twin-rotor machine can be effectively supported. The support element 11 is fastened using appropriate fasteners (not shown), such as screws. The conductor bars 6 of the winding 3 extend axially on both sides into the second axial section 7 of the stator core 2. The screw-like conductor bars 6 of the radially inner and outer layers are each connected to each other in the second axial section 7 of the stator core 2. The sub-elements 12, 13 of the support element 11 are shown here in engagement with the stator core 2.It is evident that a conductor bar 6 is placed in each stator slot 19, 20 of the stator lamination stack 18, so that all conductor bars 6 are positively coupled to the second axial section 7. Thus, a torque supported via the winding 3 can be supported via the second axial section 7 and therefore via the stator core 2 at the base attached to the bores 9. Fig. 4 shows an exploded view of a stator 1 for a radial flux twin-rotor machine according to a further embodiment. The stator 1 here has essentially the same components as described with reference to Fig. 1. Therefore, identical elements are not described again, but reference is made to Fig. 1. The support element 11 shown on the right is also designed in two parts and has a sub-element 12 for the radially inner arrangement in the stator core 2 and a sub-element 13 for the radially outer arrangement on the stator core 2.The inner sub-element 12 and the outer sub-element 13 are each provided with several circumferential bores 9 for attachment to a base, for example, the housing of a radial flux twin-rotor machine. The stator 1 in Fig. 4 differs in the design of the respective annular inner sub-element 12 and outer sub-element 13. Here, the sub-elements 12 and 13 are equipped with support grooves 8. These grooves are located on the inner circumference of the outer sub-element 13 and on the outer circumference of the inner sub-element 12, for engagement with corresponding extensions of the laminated core and / or the conductor bars 6 of the winding 3. The support grooves 8 are axially angled according to the helical shape of the conductor bars 6 and their pitch, so that they can engage with the conductor bars 6 of the winding 3.The sub-elements 12, 13 in all embodiments are preferably made of a conductive metal, particularly preferably of an aluminum alloy. The two-part design of the support element 11 allows the support grooves 8 to be easily accessible for mechanical or machining during manufacturing. Fig. 5 shows a perspective view of a winding 3. The winding 3 is constructed from the aforementioned conductor bars 6, which run helically along the central axis. For this purpose, the conductor bars 6 are not only arranged in a correspondingly interlocked manner, but are also twisted along the helix. The conductor bars 16, 17 of the inner and outer layers 14, 15 are arranged one above the other in the same orientation.The conductor bars 6 of the radial inner and outer layers 14, 15 can thus be easily conductively connected, for example, by means of converging, bent, and welded conductor bar ends 16, 17. A radially extending conductor bar segment welded to the conductor bars 6 would also be conceivable. It should be noted that the winding 3 shown here is not manufactured individually, but always in conjunction with the stator core 2. Fig. 6 shows a top view of a winding 3. This view clearly shows the precise radial alignment of the conductor bars 6 at every point of their helical path within the stator core 2, which, in the perspective shown, is aligned in the region of the central axis. The conductor bar ends 16, 17 each form the connection point between the inner and outer radial layers 14, 15.In the illustrated embodiment, the winding 3 has, by way of example, a total of six connection contacts 31. With a three-phase connection, three-phase operation is preferably provided. However, the winding 3 can be adapted to other connection configurations to a rotating field-generating winding 3 of any number of phases in a manner known in the art. Fig. 7 shows a flowchart of a method for manufacturing a stator 1. The method comprises a first step S1 of providing a stator core 2 having a first axial section 5 and a second axial section 7, each with radially outer stator slots 19 describing a helix and radially inner stator slots 20 describing a helix with the opposite winding direction. A further step S2 involves inserting individual conductor bars 6 through the inner and outer stator slots 19, 20.The conductor bars 6 are inserted, in particular, in an axial direction. Furthermore, a step S3 is provided for connecting the conductor bars 6 inserted into the inner and outer stator slots 19, 20 at the conductor bar ends 16, 17 to form conductor loops in order to form a self-supporting winding 3 comprising the conductor loops for torque support of the stator 1. An axial end 4 of the conductor loops is then... 1, which is provided for torque support, is defined. In a further step S4, a support element 11, radially extending the second axial section 7, is arranged axially flush within the second axial section 7. The axially flush arrangement of the support element 11 in step S4 comprises the axially flush arrangement of a radially inner sub-element 12 and a radially outer sub-element 13, followed by a further step S5 of positive locking, in particular by forming an interference fit or by force-fit connection, in particular by bonding the sub-elements 12, 13 to the second axial section 7 in a position axially offset in the stator core 2. Although the present invention has been fully described above with reference to preferred embodiments, it is not limited thereto, but can be modified in a variety of ways.

[0002] Reference Symbol List 1 Stator 2 Stator Core 3 Winding 4 Axial End 5 First Axial Section 6 Conductor Bar 7 Second Axial Section 8 Support Slot 9 Bore 11 Support Element 12 Radial Inner Sub-Element 13 Radial Outer Sub-Element 14 Radial Outer Layer 15 Radial Inner Layer 16 Conductor Bar End 17 Conductor Bar End 18 Stator Laminate Pack 19, 20 Stator Slots 21, 22 Stator Laminates 23 Inner Sub-Pack 24 Outer Sub-Pack S1 Step S2 Step S3 Step S4 Step S5 Step

Claims

PATENT CLAIMS 1. Stator (1) for a radial flux twin-rotor machine, in particular for a wheel hub motor, comprising: a stator core (2) having a first axial section (5) and a second axial section (7) adjoining the first axial section (5); a winding (3) placed in the stator core (2), which is designed to be self-supporting for torque support of the stator (1) and projects beyond the first axial section (5) at at least one axial end (4), wherein the second axial section (7) is provided as a support structure designed to engage with the winding (3) at the at least one axial end (4) for torque support. 2.Stator (1) according to claim 1, characterized in that the winding (3) is designed to be torsionally stiff such that a torque acting on the stator core (2) during the operation of a radial flux twin-rotor machine can be supported via the torsionally stiff winding (3) in the second axial section (7), in particular completely.

3. Stator (1) according to claim 1 or 2, characterized in that the stator core (2) comprises a stator lamination stack (18) forming the first axial section (5) and the second axial section (7), each with stator slots (19, 20) extending helically according to the winding path. wherein a single conductor bar (6) is arranged in each stator slot (19, 20) of the stator lamination stack (18) and wherein the stator slots (19, 20) in the first axial section (5) and in the second axial section (7) are configured identically or differently.

4. Stator (1) according to claim 3, characterized in that the stator slots (19, 20) in the second axial section (7) are configured as open or closed slots. 5.Stator (1) according to claim 3 or 4, characterized in that the recesses in the stator laminations (21, 22) of the first axial section (5) provided for forming the stator slots (19, 20) and the recesses in the stator laminations (21, 22) of the second axial section (7) provided for forming the stator slots (19, 20) are each identical, wherein the helical orientation of the stator slots (19, 20) in the first and second axial sections (5, 7) is provided by means of a stacking of the respective stator laminations (21, 22) twisted relative to each other. 6.Stator (1) according to one of claims 3 to 5, characterized in that the stator lamination stack (18) comprises an inner sub-stack (23) with radially inner stator slots (20) and an outer sub-stack (24) with radially outer stator slots (19), wherein the stator laminations (22) of the respective inner sub-stack (23) are designed with the same geometry and the stator laminations (21) of the respective outer sub-stack (24) are designed with the same geometry, and wherein the stator laminations (22) of the respective inner sub-stack (23). and the stator laminations (21) of the respective outer sub-package (24) are stacked in opposite directions, twisted relative to each other.

7. Stator (1) according to one of claims 3 to 6, characterized in that the stator laminations (21, 22) are configured differently with recesses for forming the stator slots (19, 20) in the first axial section (5) and in the second axial section (7), wherein the helical orientation of the stator slots (19, 20) is provided by means of different spacings of the recesses in the individual stator laminations (21, 22). 8.Stator (1) according to one of claims 3 to 6, characterized in that the recesses for radially inner and radially outer stator slots (19, 20) in the first axial section (5) and in the second axial section (7) are each integrated into a common stator lamination (21, 22), wherein the oppositely helical orientation of the radially inner and radially outer stator slots (19, 20) is provided by a continuous displacement of the inner and outer stator slots (19, 20) of the first axial section (5) and the second axial section (7) relative to each other from stator lamination (21, 22) to stator lamination (21, 22). 9.Stator (1) according to one of claims 3 to 8, characterized in that the respective stator laminations (21, 22) of the first axial section (5) and of the second axial section (7) have straight, in particular stamped, edges, wherein a width of the recesses provided for the respective stator slots (19, 20) is determined by the pitch of the screw shape. The predetermined amount of the profile and the sheet thickness is greater than the width of the conductor bars (6), such that the clear width of the respective stator slots (19, 20), reduced by the offset between the recesses of the respective stator laminations (21, 22), essentially corresponds to the width of a conductor bar (6).

10. Stator (1) according to one of the preceding claims, characterized in that the second axial section (7) has a radial extension relative to the first axial section (5), wherein the radial extension is formed by the stator core (2) or the stator laminations (21, 22) or can be designed as a support element (11) that can engage with the stator core (2).

11. Stator (1) according to claim 10, characterized in that the support element (11) is laminated. 12.Stator (1) according to one of claims 10, characterized in that the support element (11) is formed from a solid material, in particular a thermally conductive solid material, especially a metal, preferably an aluminum alloy.

13. Stator (1) according to one of claims 10 to 12, characterized in that the support element (11) can be positively connected to the second axial section (7), in particular by an interference fit or by a material bond, in particular by adhesive bonding.

14. Stator (1) according to one of claims 10 to 13, characterized in that the support element (11) is arranged to be axially flush with the second axial section (7). 15.Stator (1) according to any one of the preceding claims 10 to 14, characterized in that the support element (11) is formed by a first radially inner sub-element (12) that can be inserted into the second axial section (7) and a second radially outer sub-element (13) that can be slid onto the second axial section (7).

16. Radial flux double-rotor machine (10), in particular for a wheel hub drive, comprising: - a mechanically fixed base; - a stator (1) according to any one of the preceding claims, wherein the second axial section (7) engages with at least one axial end (4) of the winding (3) for torque support and the second axial section (7) is supported at the base; - a first rotor arranged radially inside the stator core (2); and - a second rotor arranged radially outside the stator core (2). 17.Radial flux twin rotor machine (10) Claim 16, characterized in that the second axial section (7) is provided with a support element radially extending the second axial section (7) and a support element made of a laminated or thermally conductive material, in particular a metal, preferably an aluminum alloy. (11) is connected, wherein the support element (11) is supported at the base.

18. Method for manufacturing a stator (1) for a radial flux twin-rotor machine (10), in particular a stator (1) according to any one of the preceding claims 1 to 15, comprising the steps of: - providing a stator core (2) having a first axial section (5) and a second axial section (7), each with radially outer stator slots (19) describing a helix and radially inner stator slots (20) describing a helix with the opposite winding direction; - inserting individual conductor bars (6) following the helix lines through the inner and outer stator slots (19, 20);and - connecting the conductor bars (6) inserted into the inner and outer stator slots (19, 20) at the conductor bar ends (16) to form conductor loops, wherein the second axial section (7) is provided as a support device which is designed to engage with the winding (3) at the at least one axial end (4) for torque support.

19. Method according to claim 18, characterized in that the provision of the stator core (2) comprises the production of a stator lamination stack (18), wherein individual stator laminations (21, 22) of the first axial section (5) and the second axial section (7), which have recesses for forming stator slots (19, 20), are each stacked twisted relative to one another.

20. The method according to claim 19, characterized in that the stator lamination stack (18) comprises an inner sub-stack (23) and an outer sub-stack (24), wherein in the first axial section (5) and in the second axial section (7) all stator laminations (22) of the inner sub-stack (23) are formed with the same geometry and all stator laminations (21) of the outer sub-stack (24) are formed with the same geometry, and wherein the stator laminations (22) of the inner sub-stack (23) are stacked in opposite directions to form the inner stator slots (19) and the stator laminations (21) of the outer sub-stack (24) are stacked in opposite directions to form the outer stator slots (20). 21.A method according to claim 19, characterized in that the stator lamination stack (18) has a plurality of differently shaped stator laminations (21, 22) in the first axial section (5) and in the second axial section (7), wherein the recesses for the inner and outer stator slots (19, 20) are each integrated in a common stator lamination (21, 22), and wherein the pitch of the helix is ​​realized by a continuous displacement of the inner and outer stator slots (19, 20) relative to each other from stator lamination to stator lamination, in particular with a flexible punching or laser beam cutting process.

22. A method according to any one of claims 19 to 21, further comprising the step of: arranging, in particular axially flush arranging, a support element (11) radially extending the second axial section (7) in the second axial section (7). 23.A method according to claim 22, characterized in that the axially flush arrangement of the support element (11) comprises the axially flush arrangement of a radially inner sub-element (12) and a radially outer sub-element (13). A method according to claim 22 or 23, characterized in that the step of axially flush arrangement of the support element (11) comprises a force-fit connection, in particular by forming an interference fit and / or a material-fit connection, in particular by bonding, and / or a form-fit connection, in particular by a shaft-hub connection, of the support element (11) or the sub-elements (12, 13) with the second axial section (7).

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