FIELD OF THE DISCLOSURE

The present disclosure relates to a double rotor machine for selective transmission of mechanical power and/or generation of electrical power and a drive train for a vehicle comprising such a double rotor machine.

BACKGROUND OF THE DISCLOSURE

Conventional vehicles being driven by an Internal combustion engine (ICE) rarely operate at an optimal efficiency of the ICE. Depending on the drivers input and the driveway demands, the ICE's engine speed and torque are determined and transmitted via a mechanical gearbox to the wheels. However, ICEs operate only at a high efficiency in a limited engine speed and torque region. In order to operate an ICE constantly at a high efficiency, the generated engine speed and torque should be controlled to minimize co2 emissions by staying in said high efficiency region. A Four-Quadrant Transducer (4QT) system achieving this, typically comprises an ICE, a battery and the four-quadrant transducer arranged between the ICE and the wheels. Compared to a conventional vehicle, the four-quadrant transducer serves as the gearbox, however additionally working as an electric motor and generator to compensate over/undersupply of engine speed and torque by the ICE constantly operating at high efficiency. Several four-quadrant transducers known from the prior art are described hereinafter.

FR2630868A1 published in 1 989 in the name of Jean Paul Sibeud relates to a device designed to be interposed between a rotating motor shaft and a rotating drive shaft, namely on the transmission drive train of a motor vehicle. It comprises an electric machine having in combination - on the one hand two concentric rotors, coaxial with a stator inside which they are arranged, one of these rotors being integral with the motor shaft while the other is integral with the receiver shaft - on the other hand.

US2014292131 A1 published in 2014 in the name of Caterpillar Inc. relates to a dual rotor switched reluctance machine with a fixed stator and separate input and output rotors on either side of the fixed stator is used to transmit power between a power source such as a gas engine and a mechanical drive unit such as wheels or tracks.

EP3075587A1 published 201 6 in the name of Marc Vetter relates to a drive arrangement for a motor vehicle comprising an internal combustion engine with at least one output shaft providing a rotary motion, at least one wheel, in particular at least two wheels, which is/are driven by said internal combustion engine, wherein said wheel or each of said wheels comprises a drive shaft to which said rotary motion is provided in order to drive the respective wheel. The drive arrangement comprises further at least one electromechanical machine which is arranged between said output shaft and at least one of said drive shafts, such that with the electromechanical machine the respective drive shaft is engageable and disengageable to said output shaft, wherein the rotary motion provided by the output shaft is directly or indirectly inputted in said electromechanical machine and is directly or indirectly outputted by said electromechanical machine to said drive shaft when the electromechanical machine engages the output shaft and the drive shaft.

SUMMARY OF THE DISCLOSURE

The motor-generator solutions in typical and known Four-Quadrant Transducer (4QT) drivetrains are a combination of a double rotor machine, usually a radial flux permanent magnet synchronous machine (RFPMSM) and a stator. The mechanical power from the ICE is transmitted to an outer rotor of the RFPMSM coupled to a drive shaft or the mechanical power is converted to electric power by the windings of an inner rotor and stator of the RFPMSM. The engine speed and torque transmitted to the outer rotor is controlled, resulting in the drive shaft speed being independent of the ICE.

A solution to implement such a 4QT this is a switched reluctance motor (SRM) in radial flux (RF) configuration with its simple manufacturing, robustness, easy maintenance, high efficiency, operateability in extreme conditions, low cost and fast acceleration. However, the SRMs known from the prior art have several drawbacks including high noise due to magnetic force related vibrations of stator and high torque ripple, and the drive performance depends strongly on the control strategy. It is one object of the disclosure to address at least one problem of the prior art.

A double rotor machine (DRM) according to the disclosure for selective transmission of mechanical power and/or generation of electrical power in a drive train of a vehicle is mechanically interconnectable to an electrical machine of a drive train to form an advanced four-quadrant transducer. Omitting the stator of known approaches may allow to construct a system providing both high torque density and high power density. Typically, the double rotor machine comprises an input drive shaft, an input rotor and an output rotor coupled to an output drive shaft. In a preferred variation, the double rotor machine comprises the input drive shaft for mechanically coupling the double rotor machine to an engine, in particular an internal combustion engine, an electric engine, a turbine or any other kind of engine, said input drive shaft extending in an axial direction into a housing of the double rotor machine. Usually, the input rotor is mechanically interconnected to the input drive shaft and is arranged inside the housing rotatable about a common axis of rotation. The output rotor is arranged rotatable about the common axis of rotation and is mechanically interconnected to the output drive shaft passing through the housing for mechanically coupling the double rotor machine to a consumer of mechanical power. Consumers of mechanical power may comprise at least one out of the following: the driveshaft for driving the wheels, a hydraulic or pneumatic system or the like. Depending on the design, the input rotor or the output rotor comprises a discshaped first array comprising ferromagnets and I or ferromagnetic material elements and a disc-shaped second array of ferromagnets and I or ferromagnetic material elements arranged next, preferably axially next or concentric, with first array and being spaced apart therefrom a certain distance in the axial direction, wherein at least one spacer extends in the axial direction fixedly interconnecting the first and the second array of ferromagnets and I or ferromagnetic material elements. Usually the output rotor or the input rotor respectively is arranged rotatable about the common axis of rotation between the first and the second disc-shaped array of ferromagnets. The ferromagnets and I or the ferromagnetic material elements are for example at least partially made of iron or an iron alloy (steel), in particular of iron or steel laminations. The ferromagnets and I or the ferromagnetic material elements provide for example a permanent magnetic field. In other words, the ferromagnets and I or the ferromagnetic material elements are for example permanent magnets.

In order to transmit mechanical power and/or generate electrical power, the input rotor or the output rotor typically comprises a disc-shaped array of electromagnets arranged next, preferably axially next or concentric, with the first and the second array of ferromagnets and I or ferromagnetic material elements for generating electrical power when rotating at a lower angular velocity than the input rotor.

Either the input rotor comprises the disc-shaped first and second array and the output rotor comprises the disc-shaped array comprising the electromagnets or the output rotor comprises the disc-shaped first and second array and the input rotor comprises the disc-shaped array comprising the electromagnets.

Preferably the double rotor machine has an axial flux (AF) configuration. In other words, the magnetic flux between the electromagnets of the output rotor and the ferromagnets of the input rotor is generally orientated parallel to the common axis of rotation. This allows a compact construction of the double rotor machine and improves the system's flexibility. Further, an AF topology allows an increase in the number of poles compared to the prior art and hence the power density, resulting in a DRM with higher performance. However, a radial flux configuration is possible as well. An additional benefit of the DRM according to the disclosure is that no permanent magnets are required.

During operation the output rotor is preferably drivable at a higher angular velocity than the input rotor when electrical power is supplied to the output rotor. Alternatively, or in addition, output rotor can be driven at a lower angular velocity than the input rotor to generate electrical power. This allows the ICE being operated always in the high efficiency region resulting in a 1 5% to 40% reduction in fuel consumption compared to a conventional vehicle. A reduced fuel consumption at a similar performance results in a reduction of CO2 emissions.

Good results can be achieved when at least one ferromagnet of the first array and/ or the second array has an essentially U- or V-shaped cross-section. Preferably all ferromagnets of the first array and/or the second array have an essentially U- or V- shaped cross-section.

In a preferred variation the input rotor is of a multipart design. Depending on the design, the input rotor comprises a first disc-shaped base having detachably arranged thereon in the assembled state the ferromagnets of the first array and a second disc-shaped base having detachably arranged thereon in the assembled state the ferromagnets of the second array. This allows to reduce the complexity when manufacturing the input rotor, as its parts can be produced separately and in an efficient manner. Preferably the first and/or the second base are at least partially made from a lightweight material, in particular a non-magnetic material, such as metal or metal compounds like aluminium. However other materials are possible as well such as composite materials like fiber reinforced plastics.

If appropriate the ferromagnets of the first and/or the second array are position fixed by support elements at the first and/or second disc-shaped base respectively, in particular the support elements are in a cross-sectional view at least partially arranged inside the U- or V-shape of the respective ferromagnet. Preferably the first and second disc-shaped arrays have essentially the same diameter, in particular the disc-shaped first array comprises the same number of ferromagnets as the discshaped second array.

For a high magnetic flux density, the output rotor comprises several ferromagnetic cores each having in the axial direction a first end section facing the first array of ferromagnets and a second end section facing the second array of ferromagnets. Preferably the first and/or the second end section of each ferromagnetic core is at least partially encompassed by windings of a set of windings respectively. For stabilizing the array of electromagnet, preferably a spacer is arranged between two neighboring cores respectively. This allows similar to the first and second array of ferromagnets a segmented structure I multipart design of the output rotor. If appropriate, the spacers may have an essentially rectangular cross-section perpendicular to the axial direction and the cores may have a corresponding essentially isosceles trapezoid-shaped cross-section. The ferromagnetic cores are for example made of the same material as the ferromagnets or the ferromagnetic material elements.

Typically, the number of ferromagnets or ferromagnetic material elements and the number of electromagnets have a ratio of 1 . 1 to 1 .5, in particular 1 .2. Preferred number parings of electromagnets and ferromagnets are 1 2/18 or 10/1 2 or 20/24, most preferred being 1 5 / 18 (electromagnets at the output rotor) I (ferromagnets at the input rotor, each array having 18 ferromagnets). However, depending on field of application, the numbers may vary to account for the spatial dimensions of the input and output rotors.

If present, the disc-shaped array of electromagnets usually comprises at least one set of windings electrically interconnectable to a battery for receiving and/or providing electrical energy to the battery. In a preferred variation the array of elec- tromagnet comprises three or more sets of windings. A good routing of the electrical interconnections is possible when the output shaft comprises a central opening extending in the axial direction concentrically with the common axis of rotation for running electrical interconnections of the at least one set of windings.

The input drive shaft and I or the output shaft are for example made of steel, in particular high strength steel. Further, at least some of the parts of the input rotor and or of the output rotor may be made of aluminum, in particular aerospace grade aluminum.

The ferromagnets or the ferromagnetic material elements of the first array are preferably arranged essentially mirror-symmetric relative to the ferromagnets or the ferromagnetic material elements of the second array. This results in a higher efficiency compared to configurations, wherein the first array is arranged circumferentially offset relative to the ferromagnets or the ferromagnetic material elements of the second array.

For a good performance, a distance in axial direction (parallel to the common axis of rotation) between the output rotor and the input rotor is between 0.1 mm and 2 mm, preferably between 0.5 mm and 1 .5 mm, in particular about 1 mm.

Due to the high power density of the DRM according to the disclosure a cooling means can be arranged at an outside of the housing. Said cooling means being fluidly interconnected to an inside of the housing, to provide good thermal control of the components arranged therein. Preferably the cooling means is formed as an oil spray cooling comprising at least one nozzle interconnected to an oil sink, in particular one or two units of two or three nozzles each.

Another aspect of the disclosure is directed to a drive train for a vehicle, in particular of a motor vehicle, the drive train comprising a double rotor machine as described above, wherein an electrical machine is mechanically coupled to the output shaft of the double rotor machine for example for transmission of torque therebetween. The electrical machine is typically implemented as an electric motor/ generator. In said drive train, the four-quadrant transducer is formed by the double rotor machine and the thereto mechanically coupled electrical machine, wherein the double rotor machine can be used to control engine speed provided to the wheels and the electrical machine to control the torque. The electric machine may be the stator of the double rotor machine, which is for example a part of the double rotor machine.

The vehicle of the present disclosure may include motor vehicles, heavy duty equipment, mobile and I or stationary, for example configured for high way or off high way applications. Other vehicles are also conceivable

If present, the electrical machine is usually electrically interconnected to a battery, in particular to the same battery as the double rotor machine. In some variations electrical interconnections between the battery and the double rotor machine and/or the electrical machine comprise a slip ring and I or power electronics between the double rotor machine and the battery. Preferably, the slip ring for each electrical interconnection of the double rotor machine and/or electrical machine are arranged in a common slip ring housing. For a compact construction, the output drive shaft extends in the axial direction into the slip ring housing, allowing a short wiring distance from the electromagnets to the slip rings.

In a preferred variation a control unit is interconnected to the at least one set of windings of the output rotor of the double rotor machine and being configured to receive an operator input and to control the transmission of rotational speed from the input rotor to the output rotor based on the operator input. If appropriate the control unit can be interconnected to the electrical machine and being configured to determine the torque transmitted between the output drive shaft and the electrical machine by controlling the electrical machine. This allows to control both, the torque and the engine speed provided to the consumer of mechanical power, e.g. the wheels of the motor vehicle.

In a variation, the double rotor machine further comprising at least one inverter, which is electronically connected to the disc-shaped array of electromagnets and preferably to the battery, wherein the inverter is configured to convert received electrical current. The power supply of the double rotor machine is for example the battery producing DC voltage, and the double rotor machine itself is for example a three-phase AC electric machine. The inverter of the double rotor machine connects both components by converting the DC side of the battery to a three-phase AC voltage, which the double rotor machine uses. In AC, electricity flows in both directions in the circuit as the voltage changes from positive to negative. The inverter regulates the flow of electrical power, enabling the double rotor machine to work in motor mode and in generator mode. The inverter of the double rotor machine is a three-phase inverter where 1 winding/coil is connected to 2 legs forming the halfbridge. An additional 7th leg exists in the inverter for braking.

The double rotor machine structure is preferably based on a switch reluctance machine, as when power is applied to the windings of the outer rotor connected to the traction side, the outer rotor's magnetic reluctance creates a force that aligns the inner rotor poles connected to the internal combustion engine with the nearest outer rotor pole. In order to maintain rotation, an electronic control system switches on the windings of successive stator poles in sequence so that the magnetic field of the stator "leads" the rotor pole, pulling it forward. The inverter enables this switching sequence by appropriately turning the transistors on and off in its phase legs. As a result, the desired output waveforms are delivered to the double rotor machine.

An advantageous assembly is realizable when at least one of the input rotor or the output rotor comprises a segmented rotor structure, thereby being formed out of a plurality of rotor segments.

An advantageous control of the enhancement of rotation speed is for example achievable, when the double rotor machine comprises a plurality of the disc-shaped first arrays and a plurality of the disc-shaped second arrays and a plurality of the disc-shaped arrays of electromagnets arranged next to each other, preferably axially next or concentric, and rotatable about the common axis of rotation.

A preferred mechanical connection of rotating parts is achievable when at least some of the rotating parts are connected with each other via at least one prestressed conical element, which is/are configured to release stress during operation. The pre-stressed conical element is for example arranged between the ferro- magnets I ferromagnetic material elements and the support elements of the rotors.

Improved mechanical coupling is possible when at least one bearing, preferably all bearings, of the input drive shaft is I are shrink fitted onto the input drive shaft, and I or wherein at least one bearing, preferably all bearings, of the output drive shaft is shrink fitted onto the output drive shaft. The bearings are configured to bear the respective shafts within the housing of the double rotor machine.

The disc-shaped first array in combination with the disc-shaped second array may has a number of magnetic poles is in the range from 1 5 to 20, preferably 18, and I or wherein the disc-shaped array comprising the electromagnets may has a number of magnetic poles in the range from 10 to 20, preferably 1 5.

Advantageous stability is possible with the input drive shaft and I or the output shaft being made of iron alloy, preferably steel, in particular high strength steel. Further, an advantageous reduction of rotating mass is possible when the input rotor and I or of the output rotor is/are made at least partially of aluminum, in particular aerospace grade aluminum. The support elements, the first base and I or the second base are for example made of aluminum.

The nominal DC link voltage of the double rotor machine is in the range from 250V to 400V, preferably at 375V.

It is preferred that a nominal speed of the input rotor is in the range from 2400 rpm to 3200 rpm, preferably at 2700 rpm, and I or wherein the nominal speed of the output rotor is in the range from 3600 rpm to 4500 rpm, preferably at 4200 rpm.

It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

Fig. 1 an exploded view of a first variation of a double rotor machine according to the disclosure;

Fig. 2 a partially sectioned view of the first variation of the double rotor machine;

Fig. 3 a detailed view of the double rotor machine of Fig. 2, indicated by circle O;

Fig. 4 a sectioned view of the first variation of the double rotor machine of Fig.

2 indicated by section line MM; and

Fig. 5 a schematic diagram of a first variation of a drive train according to the disclosure;

Fig. 6 a schematic diagram of a second variation of a drive train according to the disclosure;

Fig. 7 a section view of a second variation of the double rotor machine.

DESCRIPTION OF THE EMBODIMENTS Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

Figure 1 shows an exploded view of a first variation of a double rotor machine 1 according to the disclosure. Figure 2 shows a partially sectioned view of the first variation of the double rotor machine 1 , wherein Figure 3 displays a detailed view of the double rotor machine 1 of Figure 2, indicated by circle O. In Figure 4 a sectioned view of the first variation of the double rotor machine 1 of Figure 2 indicated by section line MM is shown and in Figure 5 of a first variation of a drive train 2 according to the disclosure is shown in a schematic diagram. Figure 6 shows a section view of a second variation of the double rotor machine 1 .

The first variation of the double rotor machine 1 , as shown in Figures 1 to 4, typically comprises an input drive shaft 3, an input rotor 6 and an output rotor 1 1 coupled to an output drive shaft 1 2 for selective transmission of mechanical power and/or generation of electrical power in a drive train 2 of a motor vehicle (not shown). The input drive shaft 3 is mechanically interconnectable to an ICE 4, whereas the output drive shaft 1 2 is mechanically interconnectable to the wheels 29 of a respective motor vehicle. As best visible in Figure 2, the input drive shaft 3 extends in an axial direction z into a housing 5 of the double rotor machine 1 . Attached to the input drive shaft 3 the input rotor 6 is arranged rotatable about a common axis of rotation R inside the housing 5. The output rotor 1 1 is arranged rotatable about the same common axis of rotation R and is mechanically interconnected to the output drive shaft 1 2 passing through the housing 5 opposite to the input drive shaft 3.

As visible in Figure 1 , the input rotor 3 comprises a disc-shaped first array 8 of fer- romagnets 7 and a disc-shaped second array 9 of ferromagnets 7 arranged concentric with the disc-shaped first array 8 (they rotate both about the same common axis of rotation R during operation) and spaced apart therefrom at a distance D1 in the axial direction z. Several spacers 10 extend in the axial direction z fixedly interconnecting the first and the second array 8, 9 of ferromagnets 7. The first and the second array 8, 9 of ferromagnets 7 form a cage-like structure for accommodating the output rotor 1 1 therein. Said output rotor 1 1 being arranged rotatable about the common axis of rotation R between the first and the second array 8, 9 of ferromagnets 7. The output rotor 1 1 typically comprises a disc-shaped array 14 of electromagnets 13 arranged concentric with the first and the second array 8, 9 of ferromagnets 7 for generating electrical power when rotating at a lower angular velocity than the input rotor 3.

Regarding the design of the input rotor 3 and the output rotor 1 1 , as shown in Figure 1 , both comprises a segmented I multipart structure compared know rotors. The ferromagnets 7 of the first array 8 and the second array 9 have an essentially U- or V-shaped cross-section in a plane parallel to the axil direction z. These ferro- magnets 7 are detachably arranged on a first base 1 5 or a second base 1 6 respectively and fixed thereon by support elements 17. The support elements 1 7 extend along an indentation of the ferromagnets 7 formed by their U- or V-shaped crosssection. By means of screws the support elements 1 7 are attached to the respective base 1 5, 1 6. Both arrays of ferromagnets 8, 9 of the first variation each have eighteen ( 18) ferromagnets.

The output rotor 1 1 comprises fifteen ( 1 5) electromagnets 1 3. Each electromagnet comprises a first end section 21 facing the first array 8 of ferromagnets 7 and a second end section 22 facing the second array 9 of ferromagnets 7. The distance D1 between the first end section 21 and the first array 8 of ferromagnets 7 is in the shown variation around 1 mm. Similarly, the distance D1 between the second end section 22 and the second array 9 of ferromagnets 7 is in the shown variation around 1 mm.

As can be seen in Figure 1 , the end sections 21 , 22 of each core 20 is coiled with windings 18. The windings 18 around end sections 21 , 22 of each core 20 do respectively belong to a common winding 18. The shown variation comprises three individual sets of windings 18 allowing to operate the output rotor 1 1 with three phases. For electrically interconnecting the windings 18 to a battery 1 9 for receiving and/or providing electrical energy to the battery 1 9, the output drive shaft 1 2 comprises a central opening 23 extending in the axial direction z concentrically with the common axis of rotation R for running electrical interconnections of the windings 18. Alternatively or additionally, the input drive shaft 3 may comprise a respective central opening for running electrical interconnections of the windings 18.

To provide cooling, in particular to the electromagnets 13 of the output rotor 1 1 , a cooling means 24 is arranged at an outside of the housing 5. The cooling means 24 is in the shown variation formed as an oil spray cooling 24 being fluidly interconnected to an inside of the housing 5. The oils spray cooling 24 comprises several nozzles being supplied by an oil sink to spray oil onto the rotors 3, 1 1 .

In Figure 5 the first variation of the drive train 2 is shown, said drive train 2 typically comprises an ICE 4, or any other engine, mechanically interconnected to the DRM 1 via input drive shaft 3. The DRM 1 is on the other side mechanically interconnected to an electrical machine 25 via a gearing 30 mechanically coupled to the output drive shaft 1 2. The electrical machine 25 is usually electrically interconnected to a battery 1 9, in particular to the same battery 19 as the double rotor machine 1 .

The solid lines in Figure 5 indicate an interconnection for transmission of energy, either mechanical or electrical energy. The dashed lines indicate signal paths. In the shown variation, a control unit 26 is interconnected to the at least one set of windings 18 of the output rotor 1 1 of the double rotor machine 1 . The control unit 26 being configured to receive an operator input and to control the transmission of rotational speed from the input rotor 3 to the output rotor 1 1 based on the operator input. In addition, the control unit 26 is typically interconnected to the electrical machine 25 and being configured to determine the torque transmitted between the output drive shaft 1 2 and the electrical machine 25 by controlling the electrical machine 25. The output drive shaft 1 2 is further directly or indirectly mechanically interconnectable to the wheels 29 of the respective motor vehicle by known means.

In the shown variations, the electrical interconnections between the battery 1 9 and the double rotor machine 1 and/or the electrical machine 25 each comprise a slip ring 27. As best visible in Figures 2 and 4, the slip ring 27 for each electrical interconnection of the double rotor machine 1 and/or electrical machine 25 are arranged in a common slip ring housing 28. Preferably, the output drive shaft 1 2 extends in the axial direction z into the slip ring housing 28, allowing a short wiring distance from the electromagnets 13 to the slip rings 27. The double rotor machine 1 may further comprise at least one inverter configured to convert received electrical current, either from the electrical windings 18 or from the battery 1 9 depending on the use case.

In Figure 6 a second variation of the drive train 2 is shown, said drive train 2 typically comprises an ICE 4, or any other engine, mechanically interconnected to the DRM 1 via input drive shaft 3. The DRM 1 is on the other side mechanically interconnected to an electrical machine 25 via a gearing 30 mechanically coupled to the output drive shaft 1 2. The electrical machine 25 is usually electrically interconnected to a battery 1 9, in particular to the same battery 19 as the double rotor machine 1 . Figure 6 further shows schematically the control unit 26, which is configured to control the different parts of the drive train 2. Figure 6 further shows two inverters, wherein the first is arranged between the battery 19 and the electrical machine 25 and the second is arranged between the battery 19 and the double rotor machine 1 . The inverters are configured to convert received direct current from the battery 19 into alternating current for the double rotor machine 1 or the electrical machine 25 or vice versa. Figure 6 further shows that the electrical machine 25 is mechanically coupled via the gearing 30 with the double rotor machine 1 (thereby forming for example part of the double rotor machine 1 ). Further, the double rotor machine 1 and the electrical machine 25 are coupled via the gearing 30 with the wheels 29.

Figure 7 shows a second variation of the double rotor machine 1 in a longitudinal section view. This variation differs mainly from the variation shown in Figure 4 in the bearing concept. The input drive shaft 3 is supported by two bearings arranged between the input drive shaft 3 and the housing 5. The bearings are for example shrinked onto the input drive shaft 3. The bearing arranged close to the input end of the input drive shaft 3 is for example a double roller bearing in O-arrangement and the bearing arranged close to the output drive shaft 1 2 is for example a double roller bearing in X-arrangement. Having such a bearing arrangement advantageously increases the rotational stability of the input drive shaft 3 and the input rotor 3. The output drive shaft 1 2 is according to the variations as shown in Figure 4 and as shown in Figure 6 supported by two bearings. The bearing arranged close to the input drive shaft 3 is arrange between the housing 5 of the DRM 1 and the output drive shaft 1 2. This bearing is for example a double roller bearing in X arrangement. The bearing arranged further away from the interior of the DRM 1 is arranged between the slip ring housing 27 and the output drive shaft 1 2. This bearing is for example a single roller bearing. Both bearings are for example shrinked onto the output drive shaft 1 2. Figure 7 further differs from Figure 4 in a different embodiment of the output rotor 1 2, which is composed out of a plurality of rotational symmetric parts, connected via screws, compared to the single output rotor 1 2 of Figure 4

Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the scope of the disclosure.

LIST OF DESIGNATIONS

1 Double rotor machine (DRM) 16 Second base (input rotor)

2 Drive train 17 Support element (input rotor)

3 Input drive shaft 18 Windings

4 Internal combustion engine 19 Battery (ICE) 20 Core (ferromagnetic, output ro¬

5 Housing (double rotor machine) tor)

6 Input rotor 21 First end section

7 Ferromagnet 22 Second end section

8 First array of ferromagnets 23 Central opening (output drive

9 Second array of ferromagnets shaft)

10 Spacer 24 Cooling means

1 1 Output rotor 25 Electrical machine

1 2 Output drive shaft 26 Control unit

1 3 Electromagnet 27 Slip ring

14 Array of electromagnets (output 28 Slip ring housing rotor) 29 Wheels

1 5 First base (input rotor) 30 Gearing

R Common axis of rotation D1 Distance (between first and second array of ferromagnets)

D2 Distance (between input and output rotor)