Double-rotor radial flux motor

Abstract

The invention relates to a dual-rotor radial flux motor, in particular for use in a wheel hub drive, comprising: a stator having a stator core and a torsion-resistant rigid winding accommodated therein, the conductor rods of the torsion-resistant rigid winding extend in a spiral manner in a first rotation direction inside the stator in the radial direction and extend in a spiral manner in an opposite second rotation direction outside the stator in the radial direction. And a dual rotor having an inner rotor and an outer rotor and a common central axis, in which the inner rotor and the outer rotor have respective annular bodies, which are designed to conduct flux, to which a respective plurality of permanent magnets are fixed, the cross-section of each permanent magnet being paired with a specific corner section of the annular body, the permanent magnets are designed and disposed on the respective annular body such that the axial path of a particular corner section is offset in the circumferential direction such that the permanent magnets generate a magnetic field extending obliquely with respect to the central axis. The magnetic field of the inner rotor obliquely extends along a first direction, the first direction faces a first rotation direction, and the magnetic field of the outer rotor obliquely extends along a second direction, and the second direction faces a second rotation direction.

Description

Technical Field

[0001] The invention relates to a dual-rotor radial flux motor, in particular to a wheel hub drive device. Background Art

[0002] Compared to conventional electric machines with only one rotor, electric machines with a stator and two rotors connected together for joint rotation, so-called twin-rotor machines (in addition to twin-rotor, also called multi-rotor, two-rotor, etc.), can increase the torque density and efficiency of electric drives. This is possible due to the fact that, especially in the so-called "yokeless" design, no back iron is required in the stator, so that magnetic losses can be significantly reduced. In addition, in the case of two rotors, there is basically more space available for field magnets (in the case of permanent magnet synchronous machines PSM) or conductor material (in the case of induction machines IM, or electrically excited synchronous machines ESM). Depending on the direction of the magnetic field lines in the air gap, such machines can be divided into two categories, one is axial flux-carrying type (magnetic field lines are parallel to the axis of rotation, so-called axial flux machines), and the other is radial flux-carrying type (magnetic field lines are in the radial direction in the air gap, so-called radial flux machines).

[0003] Dual-rotor axial flux motors are described, for example, in DE 10 2015 226 105 A1 and DE 10 2013 206593 A1. They are characterized by high torque and power density, but are expensive to manufacture, since very complex geometries must be stamped or manufactured using powder metallurgy in the stator core. Therefore, such motors have not yet entered the mass production stage and are only used in niche areas with high power density requirements, such as racing cars, aviation, etc. In addition, the mechanical fastening concept of the stator winding only allows the use of single-tooth windings, which have corresponding disadvantages in terms of noise excitation.

[0004] In contrast, in the case of a dual-rotor radial flux machine, in principle established manufacturing methods for the windings and the laminated core can be used which are suitable for large-scale production. In this case, however, there are important, largely unsolved technical problems with regard to supporting the torque generated in the stator core. Due to the presence of internal and external rotating components, the laminated stator core cannot be installed (e.g. pressed in, screwed or glued) in a fixed housing as is usually the case. The torque is therefore directed to the axial ends of the laminated stator core or the stator winding and supported at this location. In this respect, a variety of methods have been proposed in the prior art, but all of them have significant disadvantages in terms of functionality and / or costs.

[0005] EP 1 879 283 B1 describes a method for designing a stator winding as a so-called yoke winding. In this case, the inner and outer diameters of the annular laminated stator core are provided with grooves, between which a tangentially effective back iron (also called a stator yoke) is positioned. In this case, the forward conductor and the return conductor of each winding strand are guided in the grooves, laid radially one after the other, and wound around the yoke. The stator yoke is axially accessible between the winding strands and can be fixed to the housing, for example, by an axial screw connection (as described in JP 2018 082 600). The axial compression of the screw ensures both the torsional stiffness of the laminated core and the torque support at the axial end. The north pole and the south pole of the rotor magnetic field are positioned opposite each other. The disadvantage of this concept is that the magnetic flux must be transmitted entirely through the return yoke located between the stator slots. On the one hand, this leads to an increase in the weight of the laminated stator core and a significant increase in iron losses. The magnetic field lines of the two rotor fluxes are closed via the back iron in the laminated stator core and iron losses occur at this location. Furthermore, all individual coils of the yoke winding must be interconnected in parallel or in series in the region of the winding head, which in turn leads to conflicts between installation space and torque support. However, windings wound around the yoke allow direct mechanical contact with the laminated stator core.

[0006] Considerable weight and loss savings can be achieved if the magnetization direction of the magnets lying radially one point after another in the same direction is the same as the current supply direction of the conductors lying one after another in the grooves. In this case, the back iron in the stator can be omitted, resulting in a so-called "yokeless" dual-rotor motor with distributed windings. The magnetic field lines are closed on the rotor. No back iron is required in the stator, as a result of which both the weight and the iron losses of this type of motor are very low. However, the distributed winding does not allow direct mechanical contact with the laminated stator core to obtain torque support. For example, WO2004 / 004098 A1 describes a yokeless embodiment with distributed windings.

[0007] With regard to axial support, various auxiliary structures for torque support are proposed in the prior art, such as described in DE 10 2010 055 030 A1 or US 7,557,486 B2. The problem here is that the electrically conductive and / or magnetically conductive metal is not allowed to protrude into the flux transmission area, or is only allowed to protrude to a very limited extent, which severely restricts the material selection and geometric design. Instead, synthetic material components, adhesives and / or cast materials can also be used in the flux transmission area. However, such materials can hardly meet the strict requirements in terms of temperature stability and mechanical strength. Summary of the invention

[0008] Against this background, an object of the present invention is to provide an improved dual-rotor radial flux electric machine.

[0009] This object is achieved according to the invention by a double-rotor radial flux machine having the features of claim 1 .

[0010] Therefore, the following is provided:

[0011] A dual-rotor radial flux electric machine, in particular for use in a wheel hub drive, comprising a stator having a stator core and a torsionally rigid winding housed in the stator core, wherein in the radially inner part of the stator, the conductor bars of the torsionally rigid winding extend helically in a first direction of rotation, and in the radially outer part of the stator, the conductor bars of the torsionally rigid winding extend helically in an opposite second direction of rotation; comprising a dual rotor having an inner rotor and an outer rotor and a common central axis, wherein the inner rotor and the outer rotor each have an annular ring designed to transmit flux A body, wherein a plurality of permanent magnets are in each case fastened to the annular body, each of the permanent magnets being assigned in cross section to a predetermined angular segment of the annular body, wherein the permanent magnets are formed and arranged on the respective annular body in such a way that the predetermined angular segments are displaced circumferentially in the axial course so that the permanent magnets generate a magnetic field which extends obliquely with respect to the center axis, wherein the magnetic field of the inner rotor extends obliquely in a first direction which is oriented toward the first rotational direction and the magnetic field of the outer rotor extends obliquely in a second direction which is oriented toward the second rotational direction.

[0012] One discovery that forms the basis of the present invention lies in the fact that, in the case of a dual rotor radial flux machine, there can be magnetic field distortion due to the variation of the magnetic field in the axial direction. The magnetic field has full amplitude only in the axial center of the machine. The axial ends of the machine experience a reduction in the amplitude of the magnetic field.

[0013] A further finding which forms the basis of the invention lies in the fact that a distortion of the magnetic field leads to a shift in the maximum value of the magnetic field, with the result that a reduction in the torque occurs.

[0014] The idea underlying the invention is to provide a combination of a specific electric synchronous machine comprising: a double rotor, wherein the stator has a stator core and a torsionally rigid winding accommodated in the stator core for torque support; and a permanent magnet arrangement located in the respective rotor, the permanent magnets being displaced circumferentially in an axial course for generating a magnetic field extending obliquely.

[0015] The individual conductor bars of the torsion-resistant winding are arranged axially along the helix of the stator slots and in a first rotational direction and a second rotational direction corresponding to the radially inner stator slots and the radially outer stator slots and are connected at the conductor ends. Preferably, for this purpose, an integral joint connection by welding or brazing is provided. However, other connection techniques are also feasible. Preferably, two conductor bars are each connected at the end of the conductor bar and all conductor bars together form such a bar structure. The winding is thus formed by conductor bars connected together, in particular in the form of a bar structure. The bar structure formed with the conductor bars is advantageously configured in an inherently torsionally rigid manner and is designed for transmitting torque around the central axis of the stator. The winding thus obtains its torsional rigidity on the one hand and is additionally connected to the stator core in a form-fitting manner on the other hand for torque support.

[0016] Furthermore, the conductor bars are designed to have a thickness sufficient for transmitting power. In the case of a wheel hub motor, the thickness of the conductor bars may be, for example, in the range of several millimeters. In particular, they may be bars with a square profile with a side length of several millimeters.

[0017] The selected lead angle (also called set angle) of the stator slots or the helix described in connection therewith ensures that a conductor ring is formed by connecting the introduced conductor bars. The angle of the conductor ring in the electrical machine, i.e. the angle swept relative to the center axis, in each case surrounds the magnetic poles of the rotor. In this way, despite the functional integration, a very simple manufacture of the stator becomes possible, which is successfully implemented with very few components and relatively simple conventional connection technology and therefore with very few manufacturing steps.

[0018] A stator designed in this way can now be completed together with an innovative inner and outer rotor to form an electric machine according to the invention. The torsionally rigid winding comprises a division of the stator into a radially inner and an outer part, wherein the conductor bars of the radially inner torsionally rigid winding are arranged helically in a first direction of rotation and the conductor bars of the radially outer part are arranged helically in an opposite second direction of rotation. The continuous (tangential) displacement of the conductor bars by the axial position within the electric machine causes the magnetic field generated by the torsionally rigid winding to vary by the axial position within the electric machine. The magnetic field thus has a maximum amplitude only in the axial center of the electric machine, where conductor bars with the same coil strands and the same current direction are positioned one above the other. Due to the basic geometrical structure, the magnetic field amplitude decreases towards the two axial ends of the electric machine. The average value over the entire length is particularly important for the resulting flux linkage and the electric machine torque.

[0019] In addition to the reduction in the magnetic field amplitude, a tangential magnetic field distortion also occurs at the axial ends of the machine due to the rotational displacement of the conductor bars relative to one another, which results in a tangential displacement of the magnetic field maximum. In the case of a conventional permanent magnet configuration, this magnetic field distortion would result in a reduction in torque, since the permanent magnets in the rotor are no longer in the optimal position for generating torque in each case.

[0020] According to the invention, therefore, the torque reduction due to magnetic field distortion is counteracted by a novel matching arrangement of the permanent magnets. For this purpose, the permanent magnets of the respective rotors are displaced in the circumferential direction in the axial course, so that an obliquely extending magnetic field is generated. The oppositely obliquely extending magnetic fields generated by the inner and outer rotors extend in two oblique directions, which correspond to the respective and mutually opposite directions of rotation of the conductor bars of the torsionally rigid winding. In an advantageous manner, the innovative axial displacement of the permanent magnets in the circumferential direction has a positive effect on the torque generated, in particular enabling an increase in torque of up to 10% compared to a non-oblique arrangement of the permanent magnets in the inner and outer rotors.

[0021] The rotor is preferably manufactured from a soft magnetic solid material with surface mounted permanent magnets. In this case, the small upper field spectrum of the winding variant and the distance between the solid material and the air gap ensured by the magnets prevent the occurrence of unacceptably large losses due to eddy currents in the rotor. In this design, a relatively high degree of efficiency can also be achieved in an advantageous manner, and the rotor can still be manufactured in a very cost-effective manner.

[0022] The support means of the stator, which is particularly engaged with the torsionally rigid winding, is fixedly connected to a base as a fixed part of the motor by suitable means. For this purpose, a possible embodiment provides openings, for example through holes, for force-fitting fastening means such as screws. Of course, it is also possible to use form-fitting connection means and / or integral adhesive connection means in addition or alternatively.

[0023] In particular, the invention can be used in a particularly advantageous manner for wheel hub electric machines, in particular for motor vehicles. The structure according to the invention ensures that the weight of the dual-rotor radial flux electric machine can be reduced due to the functional integration, and the torque density can be increased, which advantageously means a reduction in unsprung masses, in particular in the case of wheel hub electric machines. Furthermore, according to the invention, a relatively short axial length can be achieved by a relatively large diameter, which is particularly advantageous in terms of torque support and installation space within the wheel.

[0024] On the other hand, according to the invention, despite the extremely compact design, very high torques are possible, in particular they are high enough to drive the wheels of the vehicle directly without a transmission. Thus, transmission losses are avoided in a particularly advantageous manner, the weight is further reduced, and particularly high advantages in terms of efficiency can be achieved.

[0025] Furthermore, for installation dimensions within the dimensions of a standard motor vehicle rim, such high torques are clearly already possible in the four-digit range, in particular greater than 1000 Nm, preferably greater than 1500 Nm, particularly preferably greater than 5000 Nm, and thus already extend to the duty limit range of standard road tires, even allowing the use of wheel hub motors to replace rear axle wheel brakes. Thus, in the use of wheel hub motors, specific synergies or functional integrations can be achieved.

[0026] Advantageous embodiments and developments emerge from the further dependent claims and from the description with reference to the drawings.

[0027] According to a preferred embodiment, the annular body is made of solid material. The torsionally rigid windings offer the possibility for the first time of designing the windings of a synchronous machine with a double rotor as distributed windings with a correspondingly small upper field spectrum. Only in this embodiment can the rotor be manufactured from solid material, since the windings only generate a small upper magnetic field and the resulting eddy currents in the rotor. Thus, when manufacturing the inner and outer rotors from soft magnetic solid material, costs can be saved due to simplified manufacturing and a high efficiency level can be achieved.

[0028] According to another embodiment, the permanent magnet is arranged at a predetermined helix angle relative to the axial direction of the central axis on the annular body. In this way, the magnetic field generated by the permanent magnet can be oriented in a targeted or purposeful manner relative to the central axis of the annular body, so as to produce the desired inclined magnetic field. The helix angle can be freely adjusted because it is mainly affected by the actual positioning and / or orientation of the permanent magnet. In this way, by the targeted or targeted adjustment of the predetermined helix angle, the torque reduction caused by the magnetic field distortion can be advantageously offset.

[0029] According to another embodiment, each of the permanent magnets is divided into a plurality of axial segments. Each axial segment is assigned an angular segment, which is displaced by a set angle around the central axis relative to the adjacent axial segment. The resulting total helix angle around the central axis or in the circumferential direction is determined according to the set angle, in particular according to a multiple of the set angle. Furthermore, the axial segments can be oriented in such a way that the edges are parallel to the central axis of the annular body. The number of axial segments and the set angles of the individual axial segments relative to each other are freely selectable. In this way, a dual-rotor radial flux motor is provided, which can be configured in relation to manufacturing costs and magnetic field optimization.

[0030] According to another embodiment, when each permanent magnet has a predetermined number of n axial segments, the resulting total helix angle φ is determined according to the set angle θ by means of the relationship φ=n*θ. Since there is a simple mathematical relationship between the number of axial segments of each permanent magnet and the set angle, the various parameters of the magnet arrangement of the rotor of the dual-rotor radial flux motor according to the present invention can be calculated by a simple method and are easy to implement. Therefore, the dual-rotor radial flux motor can be easily adapted or designed accordingly according to different requirements.

[0031] According to another embodiment, the permanent magnets are each divided into two axial segments. In this way, a variant of a double-rotor radial flux machine is provided according to the invention, which is simple to manufacture and is therefore particularly advantageous in terms of manufacturing costs. Since the number of axial segments is still small, the orientation and assembly of the segments remains relatively simple, but the torque achievable during operation is significantly increased.

[0032] According to another embodiment, the permanent magnets are oriented with their edges along a predetermined helix angle. Therefore, a dual-rotor radial flux motor is provided, which can also be adjusted and designed with integral permanent magnets according to requirements related to the predetermined helix angle. If the permanent magnets have a plane, the inclined configuration of the permanent magnets on the inner or outer circumference of the respective annular body causes a slight gap between the permanent magnets and the body in the cross section due to the geometric structure. In the case of an integrally bonded connection of the permanent magnets on the annular body, the gap is preferably filled with an integrally bonded medium. The above-mentioned integrally bonded connection can be constructed, for example, by a suitable adhesive.

[0033] According to another embodiment, the permanent magnet has an oblique parallelogram shape. The permanent magnets of the parallelogram shape have similar, in particular identical, total helix angles produced in the circumferential direction. In this way, due to the parallelogram shape, it is possible to avoid the permanent magnets leaving surface gaps or protrusions on the surface of the annular body. This makes optimal use of the surface of the annular body. Due to the configuration of the permanent magnets of the parallelogram shape in or on the annular body, gaps are similarly generated due to the geometric structure. However, for example, in the case where the permanent magnets on the annular body are connected by integral bonding, the gap can be filled by an integral bonding medium. The integral bonding connection can be constructed, for example, by a suitable adhesive.

[0034] According to another embodiment, the permanent magnet can also be formed into a rectangle, in particular a narrow rectangle. The corners of the permanent magnet can leave a relatively small free surface on each annular body, or protrude outside the body together with the corners. Since the size of the permanent magnet, in particular its width, is optional, it is also possible to adjust in this way whether the surface flows out or whether the surface protrudes. Therefore, a dual-rotor radial flux motor is provided, which can be designed in a simple manner according to requirements. In a further embodiment, further orientation of the permanent magnet is also feasible, which will produce the required inclined magnetic field.

[0035] According to one embodiment, the winding is designed to be torsionally rigid, so that during operation of the dual-rotor radial flux machine, the torque acting on the stator core can be supported, in particular completely supported, by the torsionally rigid winding on the support element. In this way, all other types of force support devices, in particular force support devices for the stator core, can be advantageously omitted.

[0036] According to another embodiment, the winding has a radially inner layer of helically arranged conductor bars radially inside the stator and a radially outer layer of conductor bars arranged in a counter-helically arranged manner radially outside the stator. In this way, a bar structure is formed by the winding and has a high torsional stiffness. The conductor bars radially inside and the conductor bars radially outside the stator each describe a helix, whose directions of rotation or pitches are opposite to each other. The angle of the helix between the start and the end of the conductor bars - swept relative to the stator center axis - is specially designed in such a way that in a dual-rotor radial flux machine, each magnetic pole of the rotor forms a conductor ring. Therefore, the sweep angle to be provided can be calculated from the quotient of a full revolution (2π or 360°) and twice the number of pole pairs p.

[0037] According to one embodiment, the radially inner and radially outer layers of the winding have in each case the thickness of a separate conductor bar. That is to say, in each case, a phase of the winding is formed which has a separate conductor bar cross section. Such a winding design according to the invention is made possible, in particular, due to the specific design of the double-rotor radial flux machine, which, by its magnetic symmetry, prevents displacement of the current to the surface, which would otherwise occur in the conductor. This allows relatively thick conductor cross sections and still achieves a relatively uniform current distribution over the cross section. For example, the thickness of the conductor bars can be in the range of several millimeters. In particular, they can be conductor bars with a square profile with a side length of several millimeters, for example in the range of 2 millimeters to 6 millimeters, in particular in the range of 3 millimeters to 5 millimeters. Similarly, other cross-sectional shapes are also possible.

[0038] According to one embodiment, the conductor bars are twisted per corresponding helical thread so that the cross section of the conductor bars is identical to the cross section radial axis at every point of the conductor. This relates in particular to the twisting of the conductor bars, in particular non-circular conductor bars, around the central axis of the stator or the motor. Depending on the helical shape of the thread, the conductor bars can also be additionally bent. The inner and outer layers are arranged in a staggered manner, i.e. rotated, twisted and bent in opposite directions relative to each other. In this way, from a mechanical point of view, the orientation of the conductor bars is ideally positioned for power transmission with the stator core at every point of the stator core, so that the individual conductor bars are uniformly loaded over their length. Therefore, in the resulting rod structure, the conductor bars advantageously absorb mainly tensile and compressive stresses when subjected to tangential forces. In this way, load peaks and deformations of the conductor bars are avoided. In particular, mechanical stresses can thus be significantly reduced when compared with a straight conductor design parallel to the axis.

[0039] According to one embodiment, the conductor bars of the radially inner and outer layers associated with the same phase winding are in each case connected together at the conductor bar ends, in particular by radially arranged conductor bar pieces and / or by an integral adhesive connection. In addition to the conductor rings or loops, this results in a construction similar to a torsionally rigid bar structure, so that when the axially accessible winding ends are fixed, the winding can absorb high torques without inducing unacceptably large deformations and / or stress states. Thus, a self-supporting design of the winding can be achieved solely by means of the winding material, for example copper, without the need for additional supporting devices or elements.

[0040] According to another embodiment, the stator core comprises a laminated stator core with stator slots extending helically corresponding to the winding threads, wherein inner stator slots radially inside the stator extend according to a first rotational direction and outer stator slots radially outside the stator extend inversely relative to each other according to a second rotational direction. The winding or a self-supporting rod structure formed therefrom is embedded in the laminated stator core. In a similar manner to the conductor rods of the winding, the stator slots change their tangential position depending on the axial position, forming a helical shape. The direction of the position change follows the conductor rod, i.e. the center line of the radially outer slot and the radially inner slot also describes a helical line, which turns in opposite directions and corresponds to the first or second rotational direction.

[0041] In the case of other embodiments, other types of manufacturing known to those skilled in the art are also feasible, which can be used to produce a stator core geometry according to the invention, whose radially inner grooves and radially outer grooves extend helically in opposite directions, in particular also additive manufacturing types such as sintering or similar methods.

[0042] According to one embodiment, only one conductor bar is arranged in each stator slot of the laminated stator core. As already explained in connection with the winding, the conductor bars of the inner and outer stator slots are interlaced spirally with each other by twisting about the central axis of the machine, so that the conductor ends of the inner and outer layers are directed toward each other. The conductor bars are electrically conductively connected together at the conductor bar ends, in particular by radially arranged conductor bar pieces and / or by an integral bonding connection, for example by welding or brazing.

[0043] According to one embodiment, the inner and outer conductively connected conductor bars together form a wavy winding strand. These winding strands can be interconnected to form a rotating magnetic field generating winding with a desired or adjustable number of strands by corresponding connection methods known to those skilled in the art. The number of strand turns for maintaining the voltage is directly determined by the quotient of the number of grooves in the numerator and the product of the number of strands in the numerator and the number of parallel branches. In an advantageous manner, the number of parallel branches is selected to be 1. In this case, the simplest possible windings are made that are interconnected.

[0044] According to one embodiment, the stator laminations of the laminated stator core are formed identically in each case, with grooves provided for forming the stator slots. The helical thread of the stator slots is formed by stacking the stator laminations in a manner rotated relative to one another. In this way, the laminated stator core can be manufactured in a very economical manner, since the same die can be used for all stator laminations arranged or stacked in parallel. Thus, two adjacent stator laminations are slightly rotated relative to one another about the central axis by a predetermined angle, so that the grooves are arranged in a manner overlapping one another, which corresponds to the thread of the helical thread.

[0045] According to another embodiment, the laminated stator core comprises an inner partial package with radially inner stator slots and an outer partial package with radially outer stator slots, wherein the stator sheets of the inner partial package are designed to have the same geometric structure in each, and the stator sheets of the outer partial package are designed to have the same geometric structure in each. In addition, the stator sheets of the inner partial package are stacked according to the first rotation direction of the conductor bar, and the stator sheets of the outer partial package are stacked according to the second rotation direction of the conductor bar, and they are twisted oppositely relative to each other around the central axis by a predetermined twist angle.

[0046] In another embodiment, the torsion angle of the stator sheet around the central axis is the same as the sweep angle of the stator slot. In this way, stator slots with opposite helical lines can be manufactured with little manufacturing cost. Nevertheless, a very economical manufacturing method is still allowed because all parallel or stacked stator sheets of the internal partial package can use the same die, and all parallel or stacked stator sheets of the external partial package can also use the same die. Therefore, two adjacent stator sheets of the internal partial package are slightly rotated relative to each other in a first rotational direction by a predetermined torsion angle around the central axis, while two adjacent stator sheets of the external partial package are slightly rotated relative to each other in a second opposite rotational direction by a predetermined torsion angle around the central axis. In this way, the grooves of the stator sheets of the internal partial package and the grooves of the stator sheets of the external partial package are arranged in a manner that overlaps relative to each other, which corresponds to the opposite helical thread trajectories.

[0047] According to one embodiment, the stator laminations of the laminated stator core are formed identically in each case, with grooves for forming the stator slots. The helical threads of the stator slots are formed by stacking the stator laminations in a manner rotated relative to one another. In this way, the laminated stator core can be manufactured very economically, since the same die can be used for all stator laminations arranged or stacked in parallel. Thus, two adjacent stator laminations are slightly rotated relative to one another about the central axis by a predetermined angle, so that the grooves are arranged in a manner overlapping one another, which corresponds to the helical threads.

[0048] According to a further embodiment, the stator sheets are formed in each case in a different manner, with grooves provided for forming the stator slots. The helical threads of the stator slots are provided by grooves at different distances in the individual stator sheets. In this case, each position of the stator sheet in the stack results in an individually adapted stator sheet shape, while individual geometries can also be repeated in the stack. In this case, production can be achieved by beam cutting processes, in particular laser beam cutting processes, which are more flexible with regard to shape than punching processes. Furthermore, it is also possible to use flexible dies with variable geometries or, in the case of very large quantities, to provide a plurality of individual punching dies or dies for each stator sheet of different shape.

[0049] According to an extended example, the grooves for the radially inner stator slots and the radially outer stator slots are each integrally formed in a common stator sheet, wherein the opposite helical threads of the radially inner stator slots and the radially outer stator slots are provided by a continuous displacement or shifting of the inner stator slots and the outer stator slots relative to each other from stator sheet to stator sheet. In this case, each position of the stator sheet in the stack also results in an individually matched stator sheet shape, wherein individual geometries can also be repeated in the stack. In this case, flexible separation processes, such as laser beam cutting, can also be used for manufacturing purposes. The thus possible one-piece production of the inner and outer grooves advantageously reduces the number of components.

[0050] According to one embodiment, the stator sheets have straight, in particular perforated edges. The width of the grooves provided for the stator slots is greater than the width of the conductor rod by an amount which is predetermined by the pitch of the helical shape of the threads of the stator slots and the sheet thickness of the stator sheets. The clear width or continuous width of the stator slots is reduced by the offset between the grooves of the stator sheets and therefore corresponds essentially to the width of the conductor rod. In practice, the continuous clear width of the stator slots is arranged to be slightly greater than the width of the conductor rod in order to provide the clearance fit required for the introduction of the conductor rod. The edges of the stator slots thus describe a staircase shape, with the thickness of the individual sheets acting as steps, on which the conductor rod is uniformly supported. In this way, it is possible to achieve uniform torque support over the entire thickness of the laminated stator core or over the entire length of the conductor rod accommodated in the laminated stator core.

[0051] According to one embodiment, the stator slots in each case sweep over an angle that is smaller than the angle swept over in each case by the conductor rods. The swept angle is in each case related to a rotation about the central axis of the stator. The difference in the swept angles is caused by the fact that the conductor rods protrude axially out of the stator core and are therefore longer than the stator slots. Since the helix also continues, a larger swept angle results. The above-mentioned difference is provided in order to ensure sufficient accessibility of the winding ends for connection, in particular welding, after the ends of the conductor rods have entered the stator slots. Furthermore, this also enables the windings to be engaged with the support device or its supporting element in an axially offset manner relative to the stator core.

[0052] From the quotient of the sweep angles, ie the ratio of the angle swept by each stator slot to the angle swept by each conductor bar, the so-called pole coverage of the laminated stator core can be defined.

[0053] According to one embodiment, the ratio of the angle swept by each stator slot to the angle swept by each conductor bar is in the range between 0.6 and 0.8, in particular between 0.6 and 0.75, preferably between 0.6 and 0.7. In this range, the ratio (pole coverage) reaches an optimum between the losses caused by current heating and the torque utilization.

[0054] According to one embodiment, at least one axial end of the winding protrudes beyond the stator core. In addition, a support device is provided, which is arranged axially offset relative to the stator core and is designed to engage with the winding in a form fit at at least one axial end for torque support.

[0055] According to an advantageous development, the support device has a support element in which the support grooves are arranged to correspond to the helical arrangement of the conductor bars and engage with the conductor bars. In this way, it can be provided that the conductor bars are positively embedded in the support element in order to support torque at the axial end. Preferably, all conductor bars are engaged in order to transmit the torque support uniformly or uniformly over the entire bar structure of the winding.

[0056] In order to transmit torque, the support element can be coupled to the mechanical fixing base of the dual rotor radial flux machine. For this purpose, a possible embodiment provides through holes for force-fit fastening means such as screws, but of course form-fit connection means or integral adhesive connection can also be used.

[0057] According to one embodiment, the support groove follows the helical thread of the twisted conductor rod at least in sections. In particular, the support groove has a similar twisted thread like the conductor rod. For example, the support element is substantially annular and has grooves on the inner and / or outer periphery, the grooves being oriented in radial direction and corresponding to the thread of the conductor rod.

[0058] According to one embodiment, the support device has a radially inner support element for engaging with a radially inner layer of conductor bars, and has a radially outer support element for engaging with a radially outer layer of conductor bars. In such an embodiment, the support elements can be annular, wherein the inner support element has grooves or teeth on its outer periphery corresponding to the threads of the inner layer of conductor bars for accommodating the radially inner conductor bars in a form-fitting manner, and the outer support element has grooves or teeth on its inner periphery corresponding to the threads of the outer layer of conductor bars for accommodating the radially outer conductor bars in a form-fitting manner. The grooves or teeth in particular follow the respective helical threads. Due to the arrangement on the inner periphery or the outer periphery, the recessed grooves are easy to machine, which simplifies the manufacture of the support element.

[0059] According to another embodiment, the total helix angle produced in the circumferential direction of the permanent magnets of the inner rotor is in the range of 20% to 40%, preferably in the range of 25% to 35%, particularly preferably in the range of 28% to 32% of the torsion angle of the inner partially encapsulated stator sheets, and / or the total helix angle produced in the circumferential direction of the permanent magnets of the outer rotor is in the range of 20% to 40%, preferably in the range of 25% to 35%, particularly preferably in the range of 28% to 32% of the torsion angle of the outer partially encapsulated stator sheets. Since the magnetic field distortion does not completely follow the thread of the stator slots of the respective stator sheets, the total helix angle produced by the permanent magnets of the inner rotor and the outer rotor is smaller than the torsion angle of the stator sheets. In this way, a particularly advantageous design is provided, which achieves an optimized torque increase through the relationship between the torsion angle of the stator sheets and the total helix angle produced by the permanent magnets.

[0060] According to another embodiment, the permanent magnets of the inner rotor and the permanent magnets of the outer rotor have a predetermined tangential width, wherein the stator core has a radial yoke thickness, the radial yoke thickness being in the range of 5% to 25% of the tangential pole width, preferably in the range of 10% to 20%, and particularly preferably in the range of 12.5% ​​to 17.5%. The tangential pole width, in particular the local tangential pole width, is preferably the common tangential width of all permanent magnets constituting the pole. In addition, the maximum tangential pole width on the cross section of the motor is arithmetically determined by the quotient of the motor radius multiplied by a full revolution (2π or 360°) divided by twice the number of pole pairs p. The radial yoke thickness of the stator core can be increased in order to carry a certain tangential flux at the end of the dual rotor radial flux motor and thus reduce the magnetic resistance. Therefore, the used radial yoke thickness of the stator can be slightly increased compared to the conventional yokeless design, but without significantly increasing the weight of the laminated stator core.

[0061] According to one embodiment, the stator core is still primarily designed to transmit radial magnetic flux. Therefore, this is still a stator core of a so-called "yokeless" design, which has no significant magnetic flux transmission in the peripheral or tangential direction, especially in the axial center of the motor.

[0062] According to one embodiment of the dual-rotor radial flux machine, the support element is fixed to the base and thus directs the torque to the fixed part of the machine. For this purpose, the support element can be fastened separately to the base of the machine, such as the housing. Alternatively or additionally, the inner support element and the outer support element can be fastened together.

[0063] According to an embodiment of the stator, the support means comprises a thermally conductive material, in particular a metal, preferably an aluminum alloy. In particular, both support elements can comprise such a material. This allows not only a high mechanical strength, but also allows heat to be dissipated from the windings through the support means.

[0064] According to an embodiment of a corresponding dual-rotor radial flux electric machine with a support device comprising a heat-conducting material, the base additionally has a heat sink, which is designed to absorb the heat dissipated from the stator, in particular from the windings, through the support device. As a result, the support device has a high mechanical strength while also ensuring a good thermal connection between the windings and the heat sink. For example, the housing of the electric machine can act as a heat sink. Alternatively or additionally, the support device, preferably the inner support element and the outer support element, can be in thermal contact with an actively cooled heat sink of the electric machine. In this way, the heat losses of the current generated in the windings or in the conductor bars can be effectively dissipated.

[0065] According to one embodiment of the dual rotor radial flux machine, a predetermined number of pole pairs are provided on both the first rotor and the second rotor. The angle swept by each conductor bar is designed to form a conductor loop or circuit for each magnetic pole of the rotor. Thus, the sweep angle to be provided can be calculated from the quotient of a full revolution (2π or 360°) divided by twice the number of pole pairs p.

[0066] Another aspect of the present disclosure relates to a method for manufacturing a stator, comprising the steps of: providing a stator core having radially outer stator slots and radially inner stator slots, the radially outer stator slots in each case describing a helix and having a first direction of rotation, the radially inner stator slots in each case describing a helix with an opposite direction of rotation; introducing individual conductor rods following the helix through the inner and outer stator slots; and connecting the conductor rods introduced into the inner and outer stator slots at the conductor rod ends to form conductor rings.

[0067] According to one embodiment of the manufacturing method, providing a stator core comprises manufacturing a laminated stator core, wherein individual stator sheets having grooves for forming stator slots are stacked in a twisted manner relative to each other. In this way, the laminated stator core can be manufactured in a very economical manner, since the same die or punching die can be used for all stator sheets arranged or stacked in parallel. Thus, two adjacent stator sheets are slightly rotated relative to each other about a central axis by a predetermined angle, so that the grooves are arranged in an overlapping manner relative to each other, which corresponds to the threads of the helix. Individual stator sheets having such a geometric structure can be manufactured in an advantageous manner by punching or laser beam cutting individual laminations formed of electrical steel.

[0068] According to an extended example of the method, the laminated stator core comprises an inner partial encapsulation and an outer partial encapsulation, wherein all stator sheets of the inner partial encapsulation are designed to have the same geometry in each case, and all stator sheets of the outer partial encapsulation are designed to have the same geometry in each case, wherein the stator sheets of the inner partial encapsulation for forming the inner stator slots and the stator sheets of the outer partial encapsulation for forming the outer stator slots are stacked in a reverse twisted manner relative to each other. In this case, all sheets of the corresponding inner and outer encapsulations can be designed to have the same geometry, thus making the manufacturing process very economical. Therefore, all stator sheets of the inner partial encapsulation arranged or stacked in parallel can use the same punching die, and all stator sheets of the outer partial encapsulation arranged or stacked in parallel can use the same punching die. Two adjacent stator sheets of the inner partial encapsulation are slightly rotated relative to each other in a first direction around the central axis by a predetermined angle, and two adjacent stator sheets of the outer partial encapsulation are slightly rotated relative to each other in a second direction around the central axis by a predetermined angle. In this way, the grooves of the stator sheets of the inner partial encapsulation and the grooves of the stator sheets of the outer partial encapsulation are arranged in a reverse overlapping manner relative to each other, which corresponds to opposite helical threads. In this way, an opposite helix of the stator slots can be produced with little manufacturing outlay.

[0069] According to a further embodiment of the method, the laminated stator core has a plurality of stator laminations formed in different ways, wherein the grooves for the inner stator slots and the outer stator slots are in each case integrated in a common stator lamination, wherein the pitch of the helix is ​​achieved by a continuous displacement of the inner stator slots and the outer stator slots relative to one another from stator lamination to stator lamination, in particular by means of a flexible punching process or a laser beam separation process. The inner stator slots and the outer stator slots are integrated into a single stator lamination (laminate), the helix of the stator slots being achieved in each individual lamination by a continuous displacement of the grooves relative to one another during the separation process, for example by means of a flexible punching process or a laser beam separation process. This has the advantage that fewer components also means that fewer manufacturing steps are required and that the stator laminations or the entire stator core thus produced have a greater mechanical strength.

[0070] In another embodiment, the method further comprises: a step of providing a support device, the support device being designed to engage with the conductor rod end in a form-fitting manner at at least one axial end for torque support; and a step of engaging the support device with the conductor rod end in a form-fitting manner at at least one axial end at a position axially offset relative to the stator core.

[0071] Furthermore, according to one aspect, a stator manufactured in this way can be used to perform a method for manufacturing a dual-rotor radial flux machine, the method also comprising the further steps of: providing a mechanically fixable base and a support device, the support device being designed to engage with the winding in a form-fitting manner at at least one axial end for torque support; fastening the support device to the base; and providing a dual rotor, the dual rotor having an inner rotor and an outer rotor and a common center axis, wherein the inner rotor and the outer rotor each have an annular body designed for transmitting flux, wherein a plurality of permanent magnets are in each case fastened to the annular body, each permanent magnet being assigned in cross section to a predetermined angular segment of the annular body, wherein the permanent magnets are formed and arranged on the respective annular body such that the angular segments are displaced circumferentially in the axial course so that the permanent magnets generate a magnetic field extending obliquely with respect to the center axis, wherein the magnetic field of the inner rotor extends obliquely in a first direction, the first direction being oriented toward the first direction of rotation, and the magnetic field of the outer rotor extends obliquely in a second direction, the second direction being oriented toward the second direction of rotation.

[0072] The above embodiments and extensions can be combined with each other in any way if the above combination is useful. In particular, all features of the stator can be transferred to the manufacturing method of the stator, and all features of the manufacturing method of the stator can be transferred to the stator. In addition, all features of the stator can be transferred to the corresponding dual-rotor radial flux machine, and an axle having such a dual-rotor radial flux machine and / or a vehicle having such an axle.

[0073] Other possible embodiments, extensions and implementations of the present invention also include non-explicitly mentioned combinations of features of the present invention that have been described or will be described below with reference to the exemplary embodiments. In particular, in this regard, those skilled in the art will also add individual aspects as improvements or supplements to the corresponding basic forms of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The invention will be explained in more detail below with the aid of exemplary embodiments shown in the schematic drawings in the accompanying drawings.

[0075] Figure 1 An exploded view of a dual-rotor radial flux machine having a stator and dual rotors is shown;

[0076] Figure 2 An exploded view of a dual rotor is shown;

[0077] Figure 3 A plan view showing two axial sections of a permanent magnet;

[0078] Figure 4 A schematic cross-sectional view showing a portion of an inner rotor and an outer rotor with permanent magnets;

[0079] Figure 5A plan view showing a parallelogram permanent magnet;

[0080] Figure 6 A schematic cross-sectional view showing a portion of an inner rotor and an outer rotor having parallelogram-shaped permanent magnets;

[0081] Figure 7 A perspective view showing the winding;

[0082] Figure 8 A perspective view showing a stator core;

[0083] Fig. 9 A cross-sectional view showing a dual rotor radial flux machine;

[0084] Fig.10 A cross-sectional view showing a dual-rotor radial flux machine according to another embodiment;

[0085] Fig.11A -C shows a cross-sectional view of a dual-rotor radial flux machine at different axial positions with marked magnetic field distortion;

[0086] Fig.12 shows a schematic longitudinal cross-sectional view of a stator;

[0087] Fig.13 A schematic longitudinal cross-sectional view showing a dual-rotor radial flux machine;

[0088] Fig.14 An exploded view of a dual-rotor radial flux machine according to one embodiment is shown;

[0089] Fig.15 shows an exploded view of a stator according to one embodiment;

[0090] Fig.16 An exploded view of a dual-rotor radial flux motor according to another embodiment is shown;

[0091] Fig.17 Shows Fig.16 A three-dimensional view of a dual-rotor radial flux motor in an installed state is shown;

[0092] Fig.18 A perspective longitudinal cross-sectional view showing a dual-rotor radial flux motor according to yet another embodiment;

[0093] Fig.19 An exploded view of a laminated stator core showing the stator core;

[0094] Fig. 20 A schematic longitudinal cross-sectional view showing a stator slot;

[0095] Fig.21 A plan view showing the windings;

[0096] Fig. 22 A perspective view showing a finite element simulation of a winding under load;

[0097] Fig.23 A perspective view showing a finite element simulation of a comparative winding with conductor bars having a straight design under load; and

[0098] Fig.24 A flow chart showing a method for producing a stator is shown.

[0099] The accompanying figures in the drawings are intended to provide a better understanding of the embodiments of the present invention. They illustrate the embodiments and, together with the description, are used to explain the principles and concepts of the present invention. Other embodiments and many of the advantages described will become clear with reference to the drawings. The elements in the drawings are not necessarily illustrated in a proportional manner relative to each other.

[0100] In the various figures of the drawings, similar and functionally identical elements, features and components and elements, features and components that function in the same manner are provided with the same reference numerals unless otherwise indicated. DETAILED DESCRIPTION

[0101] Figure 1 An exploded view of a dual-rotor radial flux machine 10 having a stator 1 and a dual rotor 100 is shown.

[0102] The stator 1 of the dual-rotor radial flux motor 10 and the dual rotor 100 have a common central axis M. The stator 1 is concentrically accommodated between the inner rotor 12 and the outer rotor 13 of the dual rotor 100 .

[0103] The stator 1 has a stator core 2 and a torsionally rigid winding 3 accommodated therein. Radially inside the stator 1, the conductor bars 6 of the torsionally rigid winding 3 extend helically in a first direction of rotation. Radially outside the stator 1, the conductor bars 6 of the torsionally rigid winding 3 extend helically in an opposite second direction of rotation.

[0104] The double rotor 100 has an inner rotor 12 and an outer rotor 13. The inner rotor 12 and the outer rotor 13 each have an annular body 102, 103. The annular bodies 102, 103 are designed for transmitting flux and have a common center axis M. In each case, a plurality of permanent magnets 29 are fastened to the annular bodies 102, 103. Each permanent magnet 29 is assigned a predetermined angular segment 32, 33 of the annular body 102, 103 in cross section. The predetermined angular segments 32, 33 extend in an arcuate manner along the circumference of the annular bodies 102, 103.

[0105] The permanent magnets 29 are designed and arranged on the respective annular bodies 102, 103 so that the predetermined angular sections 32, 33 are displaced in the circumferential direction in the axial course, so that the permanent magnets 29 generate magnetic fields 34, 35 extending obliquely with respect to the center axis M. The magnetic field 34 of the inner rotor 12 extends obliquely in a first direction, which is oriented toward the first rotation direction of the torsionally rigid winding 3. The magnetic field 35 of the outer rotor 13 extends obliquely in a second direction, which is oriented toward the second rotation direction of the torsionally rigid winding 3.

[0106] Figure 1 Magnetic fields 34 and 35 of permanent magnets 29 are illustrated by oblique dashed arrows, which in each case extend oppositely in an oblique manner. As shown, the magnetic field propagation lines of magnetic fields 34, 35 extend oppositely in an oblique manner on permanent magnets 29 of inner rotor 12 and outer rotor 13.

[0107] The construction and arrangement of the permanent magnets 29 for the displacement of the corner segments 32 , 33 along the axial course are not restricted to the design illustrated in the present case but can be modified in a variety of ways.

[0108] Figure 2 An exploded view of the twin rotors is shown.

[0109] The double rotor 100 has an inner rotor 12 and an outer rotor 13. The inner rotor 12 is concentrically accommodated in the outer rotor 13. A plurality of permanent magnets 29 are arranged on the inner surface of the annular body 103 of the outer rotor 13.

[0110] The permanent magnets 29 are assigned to predetermined angular sections 32 of the annular body 103 in cross section. Figure 2 As shown, the angular segments 32 are displaced or moved along the axial course in the circumferential direction, and the adjacent axial segments 30 of the permanent magnets are correspondingly arranged in an axially displaced manner in the circumferential direction.

[0111] In this case, the permanent magnet 29 is, for example, divided into a plurality of axial segments 30. However, in further embodiments, it is also possible to have other configurations and arrangements of the permanent magnet 29 so that the angular segments 32, 33 are displaced along the axial course.

[0112] This geometrical relationship is also similarly provided on the outer surface of the annular body 102 of the inner rotor 12. In other embodiments, instead of or in addition to the illustrated arrangement of permanent magnets on the surface of the inner and outer rotors 12, 13, the permanent magnets 29 can also be countersunk in the annular bodies 102, 103. In addition, the annular bodies 102, 103 are made of solid material.

[0113] Figure 3 A plan view of the permanent magnet 29 is shown.

[0114] The permanent magnets 29 are disposed at an exemplary predetermined helix angle ε with respect to the axial direction of the central axis M on the annular bodies 102 , 103 (not shown).

[0115] The illustrated permanent magnet 29 is for example divided into a plurality of axial segments 30. The axial segments 30 are in each case assigned to an angular segment 32, 33 (not illustrated) of the respective body which is displaced about the center axis M by a set angle θ relative to the adjacent axial segment 30.

[0116] The resulting total helix angle φ of the permanent magnets is determined from a geometrical perspective based on a set angle θ, in particular multiples of the set angle θ. In the case where each permanent magnet 29 has a predetermined number of n axial segments 30, the resulting total helix angle φ is determined based on the set angle θ by means of the relationship φ=n*θ. In addition, the predetermined helix angle ε shown by way of example in this case is configured as a function of the length of the dual-rotor radial flux motor 10. In other embodiments, the predetermined helix angle may also be defined in a manner different from that shown in the figure. In this regard, in Figure 3 ε is shown as a projection angle on the peripheral surface of the permanent magnet 29 purely by way of example.

[0117] like Figure 3 As shown, the axial segment 30 in the illustrated embodiment is provided with a long side parallel to the central axis M. In this embodiment, this makes optimal use of the surface of the annular body 102, 103. According to another embodiment, the edge of the axial segment 30 can be arranged on the annular body 102, 103 at a specific angle relative to the central axis, for example, the edge of the axial segment 30 can be oriented along a predetermined helix angle ε. In addition, in other embodiments, other orientations of the axial segment 30 can also be on the surface of the annular body 102, 103, and other orientations produce the desired overall helix angle of the arrangement.

[0118] Figure 4 A schematic sectional view of a portion of the inner and outer rotors 12 , 13 with permanent magnets 29 is shown.

[0119] like Figure 3 As shown, the permanent magnets 29 are each axially arranged one behind the other on the annular bodies 102, 103. The resulting total helix angle φ and the set angle θ about the central axis M (not shown) of the dual rotor radial flux machine 10 are also shown.

[0120] The displacement or displacement of the two axial segments 30 in the circumferential direction relative to each other is described by the setting angle θ. Due to the concentric arrangement of the annular bodies 102, 103 and the only radially offset arrangement of the axial segments 30 on the respective annular bodies 102, 103, the setting angle θ of the permanent magnets 29 has the same values ​​on the inner and outer rotors 12, 13 in opposite directions. This arrangement of the axial segments 30 also plays a decisive role in the function of the double rotor 100.

[0121] As already mentioned, the total helix angle φ generated in the circumferential direction is determined according to the set angle θ of the axial segment 30 and the number of axial segments 30. In addition, in the case of a rectangular design of the axial segment 30 of the permanent magnet 29 provided with a flat surface, there is a gap between the inner or outer circumferential surface of the annular body 102, 103 and the corresponding axial segment 30. For example, in the case of an integral adhesive connection of the axial segment 30 of the permanent magnet 29 with the annular body 102, 103, such a gap can be filled with an integral adhesive medium. The integral adhesive connection can be established, for example, with the aid of a suitable adhesive. However, it should be noted that other mechanisms and methods for fastening are possible, in particular those that do not generate a gap between the annular body 102, 103 and the corresponding axial segment 30. Alternatively or additionally, for example, local grooves of the rotor can also be used for the purpose of compensating the gap. In addition, the inner permanent magnet and the outer permanent magnet in other embodiments can have the same size, or, as shown here, can have different sizes, preferably in order to cover the same angular segment in radial orientation.

[0122] Figure 5 A plan view of a parallelogram-shaped permanent magnet 29 is shown.

[0123] The shape of the axial section 30 or the permanent magnet 29 may be different from Figure 3 Rectangular shape, such as Figure 5 As shown. The illustrated permanent magnet 29 has a parallelogram shape, wherein the hypotenuse 31 of the permanent magnet 29 is inclined at a predetermined helix angle ε relative to the axial direction of the center axis M. In this regard, the same total helix angle φ is generated in the circumferential direction around the center axis M of the permanent magnet 29. When the parallelogram permanent magnet 29 is used, the surface of the annular body 102, 103 (not shown) can be optimally utilized, the permanent magnet 29 does not protrude, and the surface is not left vacant.

[0124] Figure 6 A schematic cross-sectional view of a portion of the inner and outer rotors 12 , 13 with parallelogram-shaped permanent magnets 29 is shown.

[0125] With respect to Figure 4In a similar manner to what has been explained, the total helix angle φ produced in the circumferential direction around the central axis M can be observed as indicated. The total helix angle φ produced describes the sweep angle in the circumferential direction which is produced by the bevel 31 (not shown) of the corresponding permanent magnet 29. Figure 4 The described problem of creating gaps at the inner rotor 12 and the outer rotor 13 can be solved in a similar manner in the illustrated parallelogram permanent magnets 29. The placement of the permanent magnets 29 relative to each other on the annular bodies 102, 103 is set according to the resulting total helix angle φ. For the illustrated permanent magnets 29 on the inner and outer rotors 12, 13, the total helix angle φ relative to the circumferential direction is oppositely equal in value due to the opposite directions of rotation.

[0126] In the case of the illustrated embodiment, the inner and outer permanent magnets 29 can be of different sizes so as to cover the same angular section in the radial direction.

[0127] However, in other embodiments, the inner permanent magnet and the outer permanent magnet may also be of the same size, for example in order to reduce costs within the scope of an integration strategy.

[0128] Figure 7 A perspective view of the winding 3 is shown.

[0129] The winding 3 is composed of said conductor bars 6 which extend helically along the central axis M. For this purpose, the conductor bars 6 are not only arranged in a correspondingly staggered manner, but are also twisted with respect to one another according to the thread of the helix.

[0130] The sweep angle β of the conductor bar 6 determines the angle between the start and end of the conductor bar 6 relative to the center axis M. Since the pitch of the helix of the conductor bar 6 is equal to the pitch of the helix of the stator slots 19, 20, but the conductor bar 6 is longer than the stator slots, a ratio of the respective sweep angles α and β can be formed to characterize the geometric relationship, which ratio is also called pole coverage. In order to provide the best state between magnetic loss and torque utilization of the dual-rotor radial flux machine, this ratio (pole coverage) is preferably in the range of 0.6 to 0.75.

[0131] In this case, too, opposite rotations and twists of the radially inner and outer layers 14, 15 of the conductor bars 6 can be observed. The twist is configured so that the cross section associated with a radial line through the center of the conductor bar is always the same at every point on the conductor bar, which is also defined as a 2.5D geometry. As a result, the conductor bar ends of the inner and outer layers 14, 15 are arranged in the same orientation one after the other. As a result, the conductor bars 6 of the radially inner and outer layers 14, 15 can be connected electrically conductively in a simple manner, in this case, for example, by welding to the radially extending conductor bar pieces 17 of the conductor bars 6.

[0132] It should be noted that the windings described here are not manufactured separately, but are always manufactured in combination with the stator core 2. Fig.23 Discuss in more detail.

[0133] The winding 3 has a radially inner layer 15 of helically arranged conductor bars 6 radially inside the stator 1 (not shown) and a radially outer layer 14 of conductor bars 6 arranged in an opposite helically arranged radially outside the stator 1 .

[0134] Figure 8 A perspective view of the stator core 2 is shown.

[0135] The stator core 2 comprises a laminated stator core 18 having winding threads corresponding to helically extending stator slots 19, 20. The radially inner inner stator slots 20 of the stator 1 (not shown) extend according to a first rotational direction, and the radially outer outer stator slots 19 of the stator 1 extend in opposite directions relative to each other according to a second rotational direction.

[0136] The laminated stator core 18 includes an inner partial package 23 having radially inner stator slots 20 and an outer partial package 24 having radially outer stator slots 19. The stator sheets 22 of the inner partial package 23 are each manufactured to have the same geometric structure, and the stator sheets 21 of the outer partial package 24 are each manufactured to have the same geometric structure. The stator sheets 22 of the inner partial package 23 are stacked according to a first rotation direction of the conductor rod 6 (not shown), and the stator sheets 21 of the outer partial package 24 are stacked according to a second rotation direction of the conductor rod 6, so as to be reversely twisted relative to each other around the center axis M by a predetermined twist angle γ. The marked twist angle γ describes the angle between the axial ends of the laminated stator core 18 in the circumferential direction relative to the center axis M, which angle is caused by the rotation of the individual stator sheets 21, 22 relative to each other.

[0137] In a particular embodiment, the sweep angle α of the stator slots is the same as the twist angle γ.

[0138] Since the magnetic field distortion does not completely follow the thread of the stator slot, the total helix angle φ generated in the circumferential direction must be smaller than the torsion angle γ. Therefore, the total helix angle φ (not shown) generated in the circumferential direction of the permanent magnets 29 of the inner rotor 12 is within the range of 20% to 40% of the torsion angle γ of the stator sheets 22 of the inner partial package 23, and / or the total helix angle φ generated in the circumferential direction of the permanent magnets 29 of the outer rotor 13 is within the range of 20% to 40% of the torsion angle γ of the stator sheets 21 of the outer partial package 24. The total helix angle φ generated in the circumferential direction is adapted to the torsion angle γ as described above to maximize the increase in torque.

[0139] Fig. 9 A cross-sectional view of a dual-rotor radial flux machine 10 is shown.

[0140] The arcuate portion of the illustrated dual rotor radial flux machine 10 shows the conductor rods 6, permanent magnets 29, the stator 1, the inner rotor 12, the outer rotor 13 and the annular bodies 102, 103. In addition, the magnetic flux (amount) is also marked in the tangential direction of the inner and outer rotors 12, 13 and in the radial direction of the stator 1. In the illustrated embodiment, the stator 1 is "yokeless". Therefore, although the stator yoke 38 extends between the conductor rods 6, its function is only to mechanically hold the laminated stator core 18 (not shown) of the stator 1 together. As shown in FIG. Fig. 9 As shown, the stator yoke 38 is located in the functionally relevant magnetic flux. However, in the case of the illustrated embodiment of the dual-rotor radial flux machine 10, the tangential magnetic flux transmission at the axial ends of the dual-rotor radial flux machine 10 is reduced. This has a negative impact on the efficiency of the dual-rotor radial flux machine 10 and therefore an undesirable torque reduction occurs.

[0141] Fig.10 A cross-sectional view of a dual-rotor radial flux machine 10 according to another embodiment is shown.

[0142] and Fig. 9 Compared with the embodiment, Fig.10 The illustrated embodiment of the dual rotor radial flux machine 10 has a relatively thicker stator yoke 38 (not drawn to scale). The stator yoke 38 is described by the radial yoke thickness 36 shown.

[0143] The permanent magnets 29 of the inner rotor 12 and the permanent magnets 29 of the outer rotor 13 each have a predetermined tangential width 37. In the case of a particularly advantageous embodiment, the stator core 2 has a radial yoke thickness 36 that is in the range of 10% to 20% of the tangential width 37 of the permanent magnets 29. Thus, tangential flux transmission can be supported at the axial ends of the dual-rotor radial flux machine 10.

[0144] In an embodiment with permanent magnets 29 having a parallelogram shape, the cross section of the permanent magnets 29 is decisive for the relationship between the tangential width 37 of the permanent magnets 29 and the radial yoke thickness 36 .

[0145] Fig.11A -C shows a cross-sectional view of a dual rotor radial flux machine 10 with marked magnetic field distortion.

[0146] Three cross-sectional views (left Fig.11A , the middle Fig. 11B , on the right Fig. 11C ) each describes an axial position within the dual-rotor radial flux motor 10. The left sectional view shows the front end of the dual-rotor radial flux motor 10, the middle sectional view shows the axial center of the dual-rotor radial flux motor 10, and the right sectional view shows the rear end of the dual-rotor radial flux motor 10.

[0147] The dual-rotor radial flux motor 10 illustrated in this case includes an integral permanent magnet 29 arranged in the axial direction. As can be seen from FIG. 11 , only the dual-rotor radial flux motor 10 in the middle cross-sectional view includes a uniform magnetic field, wherein the magnetic field lines in the stator 1 extend only in the radial direction. In the left and right cross-sectional views of the dual-rotor radial flux motor 10, as shown in the figure, magnetic field distortion occurs. In the left and right cross-sectional views, the respective magnetic field lines are tilted accordingly, especially in the respective stators.

[0148] Furthermore, the displacement of the conductor rods 6 through the axial positions (front end, axial center, rear end) of the dual-rotor radial flux machine 10 can be clearly seen from the three sectional views. Only in the middle view are the conductor rods 6 with the same number of strands (U, V, W) and the same current direction (+, -) located one above the other. Therefore, the magnetic field has its maximum amplitude only in the axial center of the dual-rotor radial flux machine 10. Due to the basic geometrical relationship between the conductor rods 6 and the permanent magnets 29, the amplitude of the magnetic field decreases towards the two axial ends of the dual-rotor radial flux machine 10 (left and right sectional views). The resulting distortion of the magnetic field leads to a reduction in torque, since the permanent magnets in the rotor are no longer located in the optimal position for torque generation in each case. This situation can be seen by the reference numerals located on the corresponding annular bodies 102, 103. Figures 1 to 6 The configuration and construction of the permanent magnets 29 in the circumferential direction along the axial course are offset so that the permanent magnets 29 generate magnetic fields 34, 35 extending obliquely relative to the central axis M, and the above magnetic fields are optimally arranged within the magnetic field distortion range.

[0149] Fig.12 A schematic longitudinal section through a stator 1 is shown.

[0150] This is for a dual rotor radial flux machine 10 (see in this regard Fig.13 ), in particular, a schematic diagram of a stator 1 for a wheel hub motor. The stator has a stator core (or stator core) 2, a winding 3 and a support device 5. The stator core 2, the winding 3 and the support device 5 are designed to be rotationally symmetrical around the central axis M shown.

[0151] The winding 3 is self-supporting for torque support of the stator 1 and protrudes beyond the stator core 2 at at least one axial end 4. The support device 5 is arranged axially offset relative to the stator core 2 and is connected to the winding 3 in a form-fitting manner at at least one axial end 4 for torque support. In this way, during operation of the dual-rotor radial flux machine 10, the torque present on the stator core 2 can be supported by means of the self-supporting winding 3 on the support device 4.

[0152] The windings comprise a conductor material with low electrical resistance, preferably copper. The stator core 2 is preferably constructed of a soft magnetic material for magnetic flux transmission. The support means preferably comprise a thermally conductive material, such as an aluminum alloy. Of course, the windings 3 are electrically isolated.

[0153] Fig.13 A schematic longitudinal cross-sectional view of a dual-rotor radial flux machine 10 is shown.

[0154] This is also a purely illustrative diagram. Therefore, in addition to Fig.12 In addition to the stator 1 shown, the dual-rotor radial flux motor 10 also has a mechanically fixed base 11, a first rotor 12 and a second rotor 13. The stator core 2, the winding 3, the support device 5, the base 11, the first rotor 12 and the second rotor 13 are similarly designed to be rotationally symmetric around the central axis M shown.

[0155] The winding 3 is self-supporting for torque support of the stator 1 and protrudes beyond the stator core 2 at least at one axial end 4 and is supported on a base 11 by a support device 5. The support device 5 is arranged axially offset relative to the stator core 2 and is connected to the winding 3 in a form-fitting manner at at least one axial end 4. Again, the support device 5 is fastened to the base so that torque can be supported on the base 11 by the support device 5.

[0156] The first rotor 12 is arranged radially inside the stator core 2, and the second rotor 13 is arranged radially outside the stator core 2. The base 11 can be designed, for example, as a housing of an electric machine, in which case it comprises an L-shaped structure in a purely illustrative manner, which is shown as having two limbs 7, 8. The illustration is not to be understood as exhaustive, on the contrary, the base can also have other components and / or structural parts. The first limb 7 extends approximately radially, and the second limb 7 extends approximately axially and has the largest distance relative to the central axis M.

[0157] Purely schematically, the support device 5 is shown in one part extending in a radial manner, but it can also be arranged in multiple parts and / or have another geometry, which is configured for a positive connection to the winding 3. The illustrated overlap of the winding 3 with the base 11 is purely due to an exemplary schematic illustration and does not represent a direct connection. The winding 3 is preferably connected to the base 11 via the support element 5 for torque support.

[0158] Fig.14 An exploded view of a dual-rotor radial flux machine 10 is shown according to one embodiment.

[0159] In addition to the components of the stator 1, the dual-rotor radial flux motor 10 also has a first rotor 12, a second rotor 13 and a base 11. The first rotor 12 is arranged radially inside the stator core 2, and the second rotor 13 is arranged radially outside the stator core 2. The rotors 12 and 13 are preferably made of a soft magnetic solid material and are equipped with permanent magnets, so-called surface magnets, as magnetic poles on the respective surfaces facing the stator core. The permanent magnets 29 are as shown in FIG. Figure 1 and Figure 2 Set up as shown.

[0160] In this case, for greater clarity, the base 11 is only schematically illustrated. Fig.13 As described in , the base 11 is fastened to the support device 5 in the mounted state. The base 11 is mechanically fixed relative to a reference system of a support, such as a vehicle axle.

[0161] Fig.15 An exploded view of a stator 1 according to one embodiment is shown.

[0162] The stator 1 has a winding 3 , a stator core 2 and a support device 5 , wherein in this case an advantageous exemplary design of these components is illustrated more precisely in a perspective view.

[0163] The winding 3 is composed of an inner layer and an outer layer having a plurality of conductor bars 6 connected together in a bar structure. The conductor bars 6 in the inner layer and the outer layer are arranged relative to each other in a spiral manner and are coupled to a radial conductor piece 17 connecting the inner layer and the outer layer in an integrally bonded manner at the ends of the conductor bars.

[0164] The thickness of the inner and outer layers corresponds in each case to the thickness of the conductor bar 6. That is, the winding 3 is formed in the manner of the respective conductor bar 6 by means of individual conductor layers which form conductor loops and have a relatively large cross section.

[0165] Due to the rod structure formed with conductor rods, the winding is torsionally rigid and thus self-supporting for torque support.

[0166] The conductor bars 6 thus form wavy winding strands and can be connected to one another by means of corresponding interconnections, which are known to the person skilled in the art and are therefore not described further, such as, for example, a delta connection, a star connection or the like, to form a rotating field generating winding with an arbitrary number of strands.

[0167] By way of example, in the illustrated embodiment, the stator core 2 and the support device 5 are each composed of two parts. To assemble the stator 1, the winding 3, the stator core 2 and the support device 5 are arranged one inside the other. After assembly, these parts are coaxially oriented relative to each other on a common center axis M. The support device 5 - here taken as an example in two parts - is arranged axially offset relative to the other parts and constitutes the innermost and outermost parts of the stator 1. This is an inner ring and an outer ring, each of which is designed to have a groove for positive engagement with a conductor rod.

[0168] The stator core 2, which is divided into two parts here as an example, is formed by two laminated stator cores 18, which are rotated relative to each other in a spiral manner, which will be referred to in detail. Fig.19 Further detailed discussion.

[0169] In other embodiments, the stator core 2 and the supporting device 5 may each be formed of one component or more than two components.

[0170] Fig.16 An exploded view of a dual-rotor radial flux machine 10 according to another embodiment is shown.

[0171] In this case, the dual-rotor radial flux motor 10 has the same Fig.15 and Figure 4 The stator core 2, the winding 3, the first rotor 12 and the second rotor 13 are shown in an assembled state on the left hand side of the figure.

[0172] The support device 5 shown on the right is similarly formed from two parts, but differs in the configuration of the respectively annular inner support element 27 and the outer support element 28. In this case, the support elements 27 and 28 are provided with support grooves 26. They are provided on the inner circumference of the outer support element 28 and on the outer circumference of the inner support element 27 for engagement with the conductor bars 6 of the winding 3.

[0173] For this purpose, the support grooves 26 are designed to be axially inclined corresponding to the helical thread or the pitch of the conductor bars, so that they can engage with the conductor bars 6 of the winding 3 .

[0174] The support elements 27 and 28 are preferably made of an electrically conductive metal, particularly preferably of an aluminum alloy. The two-part design of the support elements 27, 28 makes it possible to easily access the support groove 26 for mechanical or machining during the manufacturing process.

[0175] The inner support element 27 and the outer support element 28 are each provided with a plurality of holes 9 along the circumference for fastening to the base 11. In this case, the holes 9 are arranged, for example, along a circle of holes evenly distributed over the circumference. The individual holes 9 are located slightly outside the body of the support element, so that the support elements 27 and 28 form a star shape in each case on the circumference away from the winding. Of course, other distributions of the holes 9 are also possible, as are other types of fastening means for connection to the base 11.

[0176] Fig.17 Show Fig.16 The illustrated perspective view is of the dual-rotor radial flux machine 10 in the installed state.

[0177] The support device 5 is fastened, for example, into a motor housing (not shown) through the hole 9, as a base 11, thereby transmitting the torque to the mechanically fixed part of the dual-rotor radial flux motor 10. In this way, the torque generated by the dual-rotor radial flux motor 10 is effectively supported. The fastening of the support device 5 is achieved by corresponding fastening means (not shown), such as screws.

[0178] The conductor bars 6 of the winding 3 extend axially on both sides to the outside of the stator core 2 and the first and second rotors 12, 13. The radially inner and radially outer layers of helically arranged conductor bars 6 are connected together to the outside of the stator core 2 in each case.

[0179] In this case, the support elements 27, 28 are shown as being engaged with the conductor bars 6 of the winding 3. It can be observed that a conductor bar 6 is placed in each support slot 26, so that all conductor bars are coupled to the support means in a form-fitting manner. Thus, the torque supported by the winding 3 can be supported by the support means 5 on the base 11, which is fastened to the hole 9.

[0180] Fig.18 A perspective longitudinal cross-sectional view of a dual-rotor radial flux machine 10 according to yet another embodiment is shown.

[0181] This embodiment and Fig.14 The assembly of the illustrated dual rotor radial flux machine 10 generally corresponds, and its components will be discussed in further detail below.

[0182] The stator core 2 has an inner partial encapsulation 23 and an outer partial encapsulation 24. The partial encapsulations 23, 24 extend annularly between the first and second rotors 12, 13. The cross-sectional view also makes it possible to see the inner and outer layers 14, 15 of the conductor bars 6 extending within the partial encapsulations 23, 24.

[0183] The illustrated dual-rotor radial flux motor 10 is a so-called "yokeless" design, in which the yoke is not located between two teeth of functionally related magnetic flux. Therefore, although the stator yoke 38 extends between the conductor rods 6, its function is only to mechanically hold the laminated stator core 18 together. The thickness of the radial yoke can be configured to be relatively thin, in the illustrated embodiment, for example, up to about 10% of the total radial stator thickness. In addition, due to the relatively small yoke thickness, undesirable leakage flux in the yoke is reduced. In other embodiments, for this purpose, the radial yoke thickness can be less than 30% of the total radial stator thickness, preferably less than 20%, and particularly preferably less than 10%.

[0184] The support device 5 also has an inner support element 27 and an outer support element 28. In this case, it can be clearly observed that the support elements 27, 28 are arranged axially offset relative to the stator 5 and the rotors 12, 13. Furthermore, at least parts of the support elements 27, 28 in form-fitting engagement with the conductor bars 6 of the inner and outer layers 14, 15 can be seen.

[0185] In this case, it can also be clearly seen that the conductor bars 6 of the inner and outer layers 14, 15 are connected at the conductor bar ends 16 by radially arranged conductor bar pieces 17. This connection is preferably an integral adhesive connection, for example by means of laser beam welding.

[0186] Furthermore, the surface magnets of the rotors 12 and 13 can be seen in cross section. The first rotor 12 has a plurality of permanent magnets on its outer peripheral surface. The second rotor 13 has a plurality of permanent magnets on its inner peripheral surface.

[0187] A particularly advantageous embodiment is provided if the rotor consists of a soft magnetic solid material and is manufactured with surface mounted permanent magnets. In this design, the rotor can be manufactured very cost effectively and a high degree of efficiency can be achieved.

[0188] Fig.19 An exploded view of a laminated stator core 18 of the stator core 2 is shown.

[0189] As already mentioned, the laminated stator core 18 of the stator core 2 has an inner partial encapsulation 23 and an outer partial encapsulation 24. This serves to simplify the manufacture of the stator slots 19, which are rotated in opposite directions relative to each other, with identical inner stator sheets 21 and outer stator sheets 22, which are stacked in a manner rotated relative to each other and are provided with grooves at the same positions.

[0190] In other embodiments, the stator sheets can also be integrally formed, so that a plurality of differently formed stator sheets can be provided, which have grooves arranged differently and are stacked in the order necessary to form the stator slots. In still other embodiments, a completely integrally formed stator core 2 can also be provided, which can be manufactured, for example, by additive manufacturing.

[0191] In the two-part design shown, the inner diameter of the outer partial encapsulation 24 is almost equal to the outer diameter of the inner partial encapsulation 23. This makes it possible to arrange the inner partial encapsulation 23 coaxially within the outer partial encapsulation 24.

[0192] The partial packages 23, 24 are constructed from individual annular stator sheets 21, 22 which are stacked one after the other. The stator sheets 21 of the outer partial package 24 are manufactured with grooves which are positioned distributed on the outer circumference to form the outer stator slots 19. The stator sheets 22 of the inner partial package 23 are manufactured with grooves which are positioned distributed on the inner circumference to form the inner stator slots 20. For example, such stator sheets are manufactured by punching, which is advantageous due to the edge quality and very low manufacturing costs.

[0193] The inner stator slots 19 and the outer stator slots 20 describe helices that extend in opposite directions with respect to each other at the same pitch, characterized by the indicated sweep angle α of the stator slots. The sweep angle α of the stator slots can be defined based on the angle between the position of the same stator slot on one axial side of the stator core 2 and the position on the other axial side of the stator core 2 relative to the center axis M.

[0194] In this case, the stator slots 19, 20 are designed, for example, as T-slots with rectangular recesses with a tapered opening. They are particularly designed to receive conductor bars with a rectangular cross section in a form-fitting manner. Of course, the geometry of the recesses or stator slots can be adapted to the geometry of the conductors. Other cross-sectional shapes are also possible for this purpose.

[0195] Fig. 20 A schematic longitudinal section through the stator slots 19 , 20 is shown.

[0196] The available or continuous clear width a of the stator slots 19 , 20 located inside the laminated stator core 18 is substantially equal to the width of the conductor rods 6 accommodated inside the stator core 2 .

[0197] The stator sheets 21, 22 have straight, in particular perforated, sides. Due to the offset of the sheets relative to one another, the groove width b provided for the stator slots 19, 20 is greater than the width d of the conductor bar 6 by an amount predetermined by the pitch δ of the helical shape of the thread and the thickness t of the sheets.

[0198] exist Fig. 20, the conductor bars 6 in the stator slots 19, 20 are schematically marked with dotted lines, wherein, in order to provide a clearance fit, the continuous clear width a of the stator slots 19, 20 is slightly larger than the width d of the conductor bars 6, and then the width a of the grooves in the stator sheets 21, 22 is much larger than the clear width b.

[0199] The thickness t of the sheet and the setting angle δ of the pitch of the threads of the grooves represent significant influencing factors for the difference between the width b of the groove and the clear width a of the available passage in the groove in the case of, for example, a punched flat sheet edge. This difference arises because, on the one hand, the pitch angle has to be compensated and, on the other hand, the stair-like step configuration of the laminated core has to be compensated.

[0200] In this case, the minimum dimension of the groove width a in the limiting case of an infinitely thin sheet or plate - that is, considering only the pitch angle δ of the conductor bars - will be

[0201] b = 1 / cos(δ)*d.

[0202] In order to compensate for the actual sheet metal thickness on the one hand and to provide a clearance fit which allows the conductor rod to be inserted on the other hand, the width b of the groove is in fact set even larger.

[0203] Fig. 20 The width b of the grooves shown in is dimensioned in such a way that the clear width a of the stator slots 19, 20, which is reduced by the offset between the grooves of the stator laminations, forms a predetermined clearance fit with the width d of the conductor bar 6 to be introduced into the stator slots, but the contact is nevertheless sufficiently close for uniformly distributed power transmission or torque support between the laminated stator core and the winding. Such dimensioning is possible, inter alia, due to the fact that, on the one hand, each stator lamination is formed identically with high edge quality and rotated with the same offset, and, on the other hand, only a single conductor bar 6 is placed in each stator slot 19, 20, the dimensions of which are constant.

[0204] In particular, in the illustrated embodiment, the conductor rod 6 is a rectangular rod with a side length or width of several millimeters, for example in the range of 2 mm to 6 mm, in particular in the range of 3 mm to 5 mm. Preferably, this may be a rectangular profile of 5 mm x 3 mm.

[0205] Fig.21 A plan view of the winding 3 is shown.

[0206] In this view, the precise radial orientation of the conductor bars at each point of their helical threading is clearly seen, the conductor bars being aligned in the illustrated perspective in the region of the central axis M. The conductor bar ends 16 form the connection points between the radially inner and outer layers 14 , 15 in each case.

[0207] In the illustrated embodiment, the winding has, for example, a total of twelve connection contacts 31. In the case of a three-strand interconnection, three-phase operation is preferably provided. However, the winding can be adapted to other interconnections in a manner known to those skilled in the art to form a rotating magnetic field generating winding with any number of strands.

[0208] Fig. 22 A perspective view of a finite element simulation of a winding 3 under load is shown.

[0209] In a slightly simplified case for simulation purposes, this is essentially Figure 7 Winding geometry shown. The scale shown relates to the stress in the winding, wherein, by way of example, in the case of a rectangular profile with a conductor bar 6 of 5 mm x 3 mm, this may be a scale of 0 MPa to 30 MPa.

[0210] In this example, the ends of the conductor bars are defined by a sweep angle β>0 of the conductor bars, i.e. a helical arrangement and formation or formation in a corresponding twisted manner. At the axial ends where the support means engage, the maximum torque of a correspondingly dimensioned double-rotor radial flux machine 10 is plotted, as indicated by the thick arrow, wherein, by way of example, in the case of a rectangular profile of the conductor bars 6 with 5 mm x 3 mm, this can be approximately 5000 Nm.

[0211] It is clear that due to the geometry of the helix, the stresses in the winding are very evenly distributed. Despite the obvious exaggeration of the setting, the deformations are barely noticeable. Therefore, due to this design, the stress peaks and therefore also the deformations are drastically reduced.

[0212] Due to this rod-like construction, the winding 3 can absorb high torques in a self-supporting manner without unacceptably large deformations and / or stress states when the axially accessible winding ends are fixed. This can be attributed in particular to the fact that in a rod structure, the conductor rod 6 mainly absorbs tensile and compressive stresses when subjected to tangential forces.

[0213] Thus, mechanical stresses may be significantly reduced when compared to designs with axis-parallel straight conductors.

[0214] Fig.23 A perspective view of a comparative model with a straight design and axial progression of the conductor rod 6 under load is shown.

[0215] and Fig. 22 In contrast, due to the straight design and axial progression of the conductor rod, it can be seen that Fig. 22 The stress concentrated on one side of the thread shown on the left, and due to the Fig.23 The strong deformation of the conductor rod caused by the local high stress and large deflection on one side shown on the right. Fig. 22 The same stress scale and the same deformation magnification in show the effect of different structural configurations on torsional stiffness.

[0216] Fig.24 A flow chart of a method for producing a stator 1 is shown.

[0217] The method comprises a first step S1 of providing a stator core 2 having radially outer stator slots 19 and radially inner stator slots 20, the radially outer stator slots 19 each describing a helix, the radially inner stator slots 20 each describing a helix with opposite turns. A further step S2 involves introducing a single conductor rod 6 following the helix through the inner stator slots 19 and the outer stator slots 20. In particular, the conductor rod is introduced in the axial direction. Furthermore, a step S3 is provided of connecting the conductor rods 6 introduced into the inner stator slots and the outer stator slots at the conductor rod ends 16 to form a conductor ring.

[0218] Although the present invention has been fully described above by means of preferred exemplary embodiments, the invention is not restricted thereto but can be modified in many ways.

[0219] Reference numerals list

[0220] 1 Stator

[0221] 2 stator core

[0222] 3 Winding

[0223] 4 Axial end

[0224] 5 Support device

[0225] 6 Conductor rod

[0226] 7 First limb

[0227] 8 Second limb

[0228] 9 holes

[0229] 10 Dual-rotor radial flux motor

[0230] 11. Base

[0231] 12First rotor / inner rotor

[0232] 13 Second rotor / outer rotor

[0233] 14 Radial outer layer

[0234] 15 Radial inner layer

[0235] 16 Conductor rod end

[0236] 17 Conductor rod

[0237] 18 Laminated stator core

[0238] 19, 20 stator slots

[0239] 21, 22 stator segments

[0240] 23 Internal local encapsulation

[0241] 24 External local encapsulation

[0242] 25 Support element

[0243] 26 Support groove

[0244] 27 Internal support elements

[0245] 28 External support elements

[0246] 29 permanent magnet

[0247] 30 Axial section

[0248] 31 oblique edge 32, 33 predetermined angle section 34, 35 magnetic field

[0249] 36 Yoke thickness

[0250] 37 Tangential Width

[0251] 38 stator yoke

[0252] 100 Dual rotor 102, 103 Annular body α Sweep angle of stator slot β Sweep angle of conductor bar γ Torsion angle δ Pitch ε Predetermined helix angle θ Total helix angle generated by setting angle φ a Net width b Width of slot d Width of conductor bar

[0253] M Center axis

[0254] Thickness of t sheet

Claims

1. A dual-rotor radial flux motor (10), particularly for use in a wheel hub drive device, The invention comprises a stator (1), wherein the stator (1) has a stator core (2) and a torsionally rigid winding (3) accommodated in the stator core (2), wherein: The conductor bars (6) of the torsionally rigid winding (3) extend helically in a first rotational direction in the radially inner part of the stator (1), and the conductor bars (6) of the torsionally rigid winding (3) extend helically in an opposite second rotational direction in the radially outer part of the stator (1); A double rotor (100) having an inner rotor (12) and an outer rotor (13) and a common central axis (M), wherein the inner rotor (12) and the outer rotor (13) each have an annular body (102, 103) designed to transmit flux, wherein a plurality of permanent magnets (29) are in each case fastened to the annular body (102, 103), each of the permanent magnets (29) being assigned in cross section to a predetermined angular section (32, 33) of the annular body (102, 103), The permanent magnets (29) are formed and arranged on the corresponding annular bodies (102, 103) so that the predetermined angular segments (32, 33) are displaced circumferentially in an axial process so that the permanent magnets (29) generate magnetic fields (34, 35) extending obliquely relative to the center axis (M), wherein the magnetic field (34) of the inner rotor (12) extends obliquely in a first direction, the first direction being toward the first rotation direction, and the magnetic field (35) of the outer rotor (13) extends obliquely in a second direction, the second direction being toward the second rotation direction.

2. The dual-rotor radial flux motor (10) according to claim 1, characterized in that: The annular body (102, 103) is made of solid material.

3. A dual-rotor radial flux machine (10) according to any one of the preceding claims, characterized in that The permanent magnet (29) is arranged at a predetermined helix angle (ε) relative to the axial direction of the central axis (M) on the annular body (102, 103).

4. A dual-rotor radial flux machine (10) according to any one of the preceding claims, characterized in that Each of the permanent magnets (29) is divided into a plurality of axial segments (30), wherein each of the axial segments (30) is assigned an angular segment (32, 33), and the angular segment is shifted by a set angle (θ) around the central axis (M) relative to the adjacent axial segment (30), wherein the resulting total helix angle (φ) in the circumferential direction is determined according to the set angle (θ).

5. The dual-rotor radial flux motor (10) according to claim 4, characterized in that: When each permanent magnet (29) has n predetermined number of axial segments (30), the resulting total helix angle (φ) in the circumferential direction is determined according to the set angle (θ) by means of the relationship φ=n*θ.

6. The dual-rotor radial flux motor (10) according to claim 4 or 5, characterized in that: Each of the permanent magnets (29) is divided into two axial sections (30).

7. The dual-rotor radial flux motor (10) according to claim 3, characterized in that: The permanent magnet (29) is oriented with its edge along the predetermined helix angle (ε).

8. The dual-rotor radial flux motor (10) according to claim 7, characterized in that: The permanent magnet (29) has an oblique parallelogram shape.

9. A dual-rotor radial flux machine (10) according to any one of the preceding claims, characterised in that The winding (3) has a radially inner layer (15) of the conductor bars (6) arranged in a spiral manner radially inside the stator (1), and has a radially outer layer (14) of the conductor bars (6) arranged in a reverse spiral manner radially outside the stator (1).

10. A dual-rotor radial flux machine (10) according to any one of the preceding claims, characterised in that The stator core (2) comprises a laminated stator core (18) with stator slots (19, 20) extending helically corresponding to winding threads, wherein inner stator slots (20) radially inside the stator (1) extend according to the first rotation direction, and outer stator slots (19) radially outside the stator (1) extend in opposite directions relative to each other according to the second rotation direction.

11. The dual-rotor radial flux motor (10) according to claim 10, characterized in that: The laminated stator core (18) comprises an inner partial encapsulation (23) with radially inner stator slots (20) and an outer partial encapsulation (24) with radially outer stator slots (19), wherein the stator sheets (22) of the inner partial encapsulation (23) are designed to have the same geometry in each case and the stator sheets (21) of the outer partial encapsulation (24) are designed to have the same geometry in each case, wherein the stator sheets (22) of the inner partial encapsulation (23) according to a first rotational direction of the conductor bar (6) and the stator sheets (21) of the outer partial encapsulation (24) according to a second rotational direction of the conductor bar (6) are stacked in such a way that they are relatively twisted relative to each other about the center axis (M) by a predetermined twist angle (γ).

12. The dual-rotor radial flux motor (10) according to claim 11, characterized in that: The total helix angle (φ) generated in the circumferential direction of the permanent magnets (29) of the inner rotor (12) is in the range of 20% to 40% of the torsion angle (γ) of the stator sheets (22) of the inner partial encapsulation (23), preferably in the range of 25% to 35%, particularly preferably in the range of 28% to 32%, and / or the total helix angle (φ) generated in the circumferential direction of the permanent magnets (29) of the outer rotor (13) is in the range of 20% to 40% of the torsion angle (γ) of the stator sheets (21) of the outer partial encapsulation (24), preferably in the range of 25% to 35%, particularly preferably in the range of 28% to 32%.

13. A dual-rotor radial flux machine (10) according to any one of the preceding claims, characterised in that The permanent magnets (29) of the inner rotor (12) and the permanent magnets (29) of the outer rotor (13) have a predetermined tangential width (37), wherein the stator core (2) has a radial yoke thickness (36), and the radial yoke thickness (36) is in the range of 5% to 25% of the tangential pole width, preferably in the range of 10% to 20%, and particularly preferably in the range of 12.5% ​​to 17.5%.

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