WO2017211793A1

WO2017211793A1 - Electric powertrain, transmission, and vehicle

Info

Publication number: WO2017211793A1
Application number: PCT/EP2017/063667
Authority: WO
Inventors: Patrick Alfons Jozef DEBAL; Saphir Elias FAID; Reinout Geert Bart GROMMEN
Original assignee: Punch Powertrain NV
Current assignee: Punch Powertrain NV
Priority date: 2016-06-08
Filing date: 2017-06-06
Publication date: 2017-12-14
Anticipated expiration: 2018-12-08
Also published as: BE1024269A1; BE1024269B1; DE212017000137U1; CN212242935U

Abstract

The present disclosure relates to a powertrain (K) for driving a vehicle (C). The powertrain (K) comprises two powertrain modules (Y,Y') comprising each a rotating machine (M,M') and a transmission (T,T'). The transmissions (T,T') are arranged to align their respective output shafts (S2,S2') towards a common wheel axis (A1) for driving a pair of opposite wheels of the vehicle (C). The first rotating axis (A3), the second rotating axis (A3) and a central axis (A0) of the powertrain K are parallel and offset with respect to the each other and the first rotating axis (A3) and the second rotating axis (A3') are mirror-symmetrically offset on opposite sides of the central axis (A0). In this way a compact and versatile design is achieved.

Description

ELECTRIC POWERTRAIN, TRANSMISSION, AND VEHICLE

TECHNICAL FIELD AND BACKGROUND

The present disclosure concerns a powertrain, a transmission for use in the powertrain, and a vehicle comprising the powertrain and/or the transmission.

Vehicles, such as cars, vans or trucks are usually driven by an engine. Electric vehicles use an electric machine for driving the vehicle instead of or in addition to a combustion engine. The electric machine can typically function both as a motor and generator. Electric vehicles can offer advantages over conventional vehicles, i.e. vehicles employing only a combustion engine, e.g. with respect to emission of exhaust gasses and versatility of the driving mechanism. The electrical machine typically comprises a machine shaft comprised in a rotor. The rotor is electrically driven to rotate with respect to a stator of the machine to provide a certain torque and/or angular velocity to the machine shaft. A transmission can be used for engaging the machine shaft and transmitting the torque and/or angular velocity of the machine shaft to an output shaft, e.g. comprising or engaging a wheel bearing shaft connected to one or more wheels of the vehicle. The machine and transmission can be part of an integrated powertrain, e.g. machine block, for easy instalment in the vehicle. The term powertrain may generally refer to a group of components (electric machine, transmission, drive shafts, differentials) that generate power delivered to propel the vehicle.

For increased driving control, it can be desirable to provide separate electric machines for different wheels of the vehicle. The separate electric machines are typically equipped with respective transmissions. A disadvantage of using multiple machines and transmissions can be that these components may occupy a large space in the vehicle. This may be exacerbated by the presence of typically large batteries that power the electric machines. Furthermore, the components can be dimensionally constrained by a width and/or length of the vehicle. Furthermore, the custom production and/or maintenance of components such as transmissions and electric machines can be expensive.

Similar drawbacks may occur in vehicles and/or apparatuses driven by other rotating machines, such as hydraulic machines or

pneumatic machines. There is a need for a compact, efficient, integrated approach for a power train comprises more than one rotating machine.

Accordingly, there is a desire to provide an improved powertrain that obviates one or more of the above mentioned disadvantages.

SUMMARY

A first aspect of the present disclosure provides a powertrain for driving a vehicle, the powertrain comprising a first powertrain module comprising a first rotating machine, comprising a first machine shaft arranged to be rotationally driven by the first for providing a torque to the first machine shaft around a first rotating axis; a first transmission, comprising first torque transmitting elements arranged for transmitting the torque of the first machine shaft to a first output shaft, wherein the first output shaft has an output direction opposite to that of a second output shaft, wherein the first torque transmitting elements are housed in a first transmission housing; a second powertrain module comprising a second rotating machine, comprising a second machine shaft arranged to be rotationally driven by the second machine for providing a torque to the second machine shaft around a second rotating axis; a second transmission, comprising second torque transmitting elements arranged for transmitting the torque of the second machine shaft to the second output shaft, wherein the first output shaft has an output direction opposite to that of the second output shaft , wherein the second torque transmitting elements are housed in a second transmission housing; wherein the first and second output shafts of respectively the first and second powertrain modules are arranged on a first and second output axis to direct the first and second output shafts towards wheel axes for driving a pair of opposite wheels of the vehicle; wherein the first rotating machine is arranged in front of the second rotating machine; wherein the first rotating axis, the second rotating axis are parallel and offset with respect to the each other;

The two powertrain modules may form together the powertrain, wherein the powertrain modules may be interchangeable. The two powertrain modules are assembled in such a way that no or a limited number of additional components may be necessary to suspend the powertrain in a vehicle. Thus, by having a powertrain comprising two the same powertrain modules, the complexity, number of components, variety of components and costs may be reduced.

By arranging the first machine in front of the second machine, as seen from the side of the powertrain, i.e. seen in a direction transverse to the rotating axes direction, and by having the first rotating axis and the second rotating axis mirror- symmetrically offset with respect to each other, a more compact and versatile design is achieved. By arranging the first electric machine in front of the second electric machine, e.g. wherein an axial position of the first rotating machine along a direction of rotating axes at least partially overlaps with an axial position of the second rotating machine, a width of the machines (measured along a direction of the rotating axes of the powertrain, or along a direction of a central axis of the powertrain, i.e. along a width of the vehicle, when assembled in the vehicle) can be less than a sum of a width of the first rotating machine and a width of the second rotating machine. Accordingly, a width occupied by the powertrain in the vehicle or apparatus can be reduced, e.g. compared to a configuration wherein the machines are placed next to each other on a left side and right side in the vehicle. Furthermore, by said arrangement of the machines, one in front of the other, a dimension of the machine measured along the direction of the rotating axes can be larger, being less constrained by a width of the vehicle. Accordingly a larger rotating machine can be used.

By placing the first axis and the second rotating axis mirror- symmetrically offset on opposite sides of a central axis of the powertrain, it becomes possible to have the same powertrain modules with the same transmissions and rotating machines fit on either side of the powertrain. The powertrain modules including transmissions and rotating machine are then mirror imaged, by means of point reflection, on both sides of the powertrain. By having the first Powertrain module interchangeable with the second powertrain module, only one type of transmission, rotating machine and other components need to be manufactured that can be used on either side of the powertrain. Also, by the symmetric arrangement of the

powertrain, the first rotating machine can be interchangeable with the second rotating machine. The reduction in the number of specific

components can provide advantages in manufacturing and/or maintenance and/or stock management. For example, a single type of rotating machine and transmission can be integrated twice in the powertrain according to the invention, thereby reducing complexity and thus costs.

The torque transmitting elements can for example be a gear drive, a chain drive, a belt drive or other torque transmitting elements. Many variants are possible.

To provide an even more compact powertrain, the first rotating axis, the second rotating axis, and the central axis can be arranged in a triangular configuration, when seen from a side of the powertrain. Also, the first rotating axis, the second rotating axis and the output axes can form a triangular configuration, which may be a different triangular configuration on either side of the powertrain. When the vehicle is driving in a straight line, both wheel axes of the pair of opposite wheels coincide with each other, which is not the case when driving a curve or in an otherwise uneven way. By said triangular configuration of the three axes, an increased distance can be provided for the torque transmitting elements between the rotating axis and the wheel axis, while still having the machines close together. This can save space along a length direction of the vehicle.

A second aspect of the present disclosure provides a transmission for use in a powertrain according to the first aspect, the transmission comprising torque transmitting elements arranged for transmitting torque of a first machine shaft of a first rotating machine to a first output shaft; wherein the transmission comprises an input side for engaging the first machine shaft and an opposite output side for engaging the first output shaft; wherein the transmission supports the first rotating machine and a second rotating machine at the input side.

The transmission according to the second aspect can be advantageously used e.g. in a powertrain according to the first aspect, providing similar advantages. Supporting the machines by means of the transmission can have an advantage that a more compact design of a powertrain can be achieved. For example, the transmission can provide a support structure arranged for supporting a first and second machine in a mirror symmetrical fashion, by means of point reflection. This can enable using an interchangeable transmission on either sides of the powertrain. By housing a bearing for carrying the machine shaft inside the transmission, a bearing in the machine can be further supported or even omitted. This can provide additional savings in manufacturing and/or maintenance cost. For example, the bearing can be lubricated by a lubrication system of the transmission, providing less wear to the bearing. A third aspect of the present disclosure provide a powertrain comprising two powertrain modules which may be assembled, disassembled and/or fixed together in a mirror imaged orientation. Each powertrain module may comprise mating structures which may be received and/or engaged by the mating structures of the other powertrain module. The mating structures which may preferably be fitted together as a mirror inverted/imaged construction which enhances the modularity, simplicity and compactness of the powertrain. These mating structures may be provided on several components of the powertrain modules. Each powertrain module may preferably be identical which may result in a compact powertrain and reduce assembly-,

manufacturing- and repairing-/maintenance- costs. Preferably, two powertrain modules may, when assembled together, form a powertrain. However, it may be possible to use only one powertrain module in a vehicle as powertrain.

A fourth aspect of the present disclosure provides a vehicle comprising a powertrain according to the first aspect and/or a transmission according to the second aspect. The vehicle may have similar advantages in terms of space saving and/or production/maintenance costs as mentioned above.

BRIEF DESCRIPTION OF DRAWINGS

These and other features, aspects, and advantages of the apparatus, systems and methods of the present disclosure will become better understood from the following description, appended claims, and accompanying drawing wherein:

FIG 1 shows a schematic side view and top view of an embodiment of a powertrain;

FIG 2 shows a schematic side view and top view of an embodiment of a vehicle with the powertrain of FIG 1;

FIG 3 shows a schematic top view of parts forming an embodiment of the powertrain;

FIG 4A shows a schematic top view of an embodiment of a powertrain;

FIG 4B shows a schematic top view of another embodiment of a powertrain; FIG 5 shows a schematic top view of another embodiment of a powertrain; and

FIG 6 shows side view and top view of an embodiment of a powertrain according to the invention.

DESCRIPTION OF EMBODIMENTS

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly

understood by one of ordinary skill in the art to which this invention belongs as read in the context of the description and drawings. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods. Terminology used for describing particular embodiments is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood that the terms "comprises" and/or "comprising" specify the presence of stated features but do not preclude the presence or addition of one or more other features. It will be further understood that when a particular step of a method is referred to as subsequent to another step, it can directly follow said other step or one or more intermediate steps may be carried out before carrying out the particular step, unless specified

otherwise. Likewise it will be understood that when a connection between structures or components is described, this connection may be established directly or through intermediate structures or components unless specified otherwise. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

The machine is a primary source of rotational energy e.g. in a vehicle or an apparatus otherwise. The machine typically comprises a machine shaft that is a mechanism receiving rotational motion from the machine and transferring such motion, e.g. to a transmission also referred to as the transmission. The transmission can be of modular design, e.g. comprising a transmission housing with torque transmitting elements therein. The housing of the transmission can be any suitable shape, e.g. not limited to a "box" shape. Modular design of the transmission or other parts of the powertrain may improve manufacturing cost and/or time. Typically, the transmission comprises torque transmitting elements capable of changing a speed ratio and/or rotational direction between a the machine shaft and a wheel bearing shaft. The torque transmitting elements typically comprises a mechanism including relatively rotatable bodies having engaging surfaces whereby a rotatable body will impart to or receive rotary motion or power from another rotary body by rolling contact. The term "torque transmitting elements" may include other transmission mechanisms for transmitting rotational motion such as belts and/or chains. In a reduction transmission, the torque transmitting elements is arranged to reduce the angular velocity of the machine shaft to the wheel bearing shaft. As a result, a torque on the wheel bearing shaft can be increased compared to the machine shaft. The transmission may also comprise a clutch that can engage/disengage the torque transmitting elements and/or change a speed ratio/rotational direction between the input shaft and the output shaft or wheel bearing shaft. The output shaft refers to a mechanism that receives rotational motion from the torque transmitting elements and transfers such motion to a load. The load can be a mechanism, e.g. wheel bearing shaft, that receives rotational motion from the torque transmitting elements to do useful work, e.g. put a vehicle in motion.

The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, 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 be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and/or cross-section illustrations of possibly idealized embodiments and intermediate structures of the invention. In the

description and drawings, like numbers refer to like elements throughout. Also, in the description and figures, reference numerals accompanied by a prime symbol (') can refer to similar elements as indicated by the same reference numerals without the said prime symbol. These elements are typically counterparts of interchangeable or identical structures, e.g. the first and second transmissions, machines, and/or their constituent parts, e.g. gears, bearings, shafts, et cetera. The counterparts will not always be separately discussed and, unless otherwise indicated, may fulfil the same or similar function. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise. FIG 1 shows a schematic side view Vs and top view Vt of an embodiment of a powertrain K.

FIG 2 shows a vehicle C comprising a powertrain K as described herein. In particular, the vehicle C comprises a transmission T as described herein.

The powertrain K comprises two powertrain modules Y, Y', comprising a respective first rotating machine M and second rotating machine M' as well as a respective first transmission T and second transmission T'. Each rotating machine M, M' comprises or engages a respective machine shaft Si, Si'. The machine shafts Si, Si' are arranged to be rotationally driven by the respective rotating machine M, M' for providing a torque to the respective machine shaft Si, Si' around a respective first and second rotating axis A3, A3'. The transmissions T, T' each comprise torque transmitting elements, in this embodiment a gear transmission, which, in this case is formed by gears Gl,G2,G3,G4 or gears Gl',G2',G3',G4'. In another embodiment, only a single set of gears Gl, G2 may be sufficient to provide for the transmission ratio and/or direction. The gear transmissions are arranged for transmitting torque of the respective machine shaft Si, Si' to a respective first and second output shaft S2,S2', wherein the gear transmissions may be housed in a transmission housing Z, Z' The first output shaft S2 has an output direction opposite to the output direction of the second output shaft S2', i.e. the output shaft S2 sticks out of the powertrain K at an opposite side with respect to the output shaft S2', as shown in the top view Vt. In the top view Vt of FIG 1 the output shafts extend outwardly with respect to the powertrain K, however in other embodiments the output shafts may extend inwardly with respect to the powertrain K. The first and second transmissions T, T' are in this

embodiment arranged to align the respective output shafts S2, S2' to the wheel axes Al, Α of a pair of opposite wheels. When both of the opposite wheels are parallel, for example when the vehicle is driving in a straight line, the wheel axes Al, Al' of the opposite wheels coincide. This is the situation shown in Fig. 1. In other circumstance the wheel axes Al, Al' of the pair of opposite wheels do not coincide with each other shafts and joints, e.g. a homo-kinetic joint, well known to the person skilled in the art may be used to connect the output shafts to the respective wheels, allowing suspension movement and vehicle turning.

As shown e.g. in FIG 2, the output shafts S2, S2' are thus arranged for driving a pair of opposite wheels of the vehicle C, e.g. a pair of front wheels Wlf and Wrf or a pair of rear wheels Wlb and Wrb. Fig. 2 also shows the vehicle with the wheels parallel, and thus with coinciding wheel axes Al, Al'. In the embodiments shown here, the coinciding wheel axes Al, A'l coincide with a central axis AO of the powertrain K. However, the powertrain K may have a different position inside the vehicle, for example more to the front of the vehicle or more to the rear, or the powertrain K may even be provided to drive the pair of rear wheels. Moreover, it may even possible provide a powertrain K to drive the front wheels and to provide a second powertrain K (not shown) to drive the rear wheels. Many variants are thus possible regarding the position of the powertrain K with respect to the wheel axes Al, Al'.

More in general, the first and second output shafts S2, S2' are arranged on a first and second output axis A2, A2'. In the embodiment shown in FIG 1, showing the pair of wheels parallel, the first and second output axis A2, A2' coincide with the wheel axes Al, Al', and with the central axis AO of the powertrain, such that the first and second output shafts S2, S2' are aligned with respect to each other and extend in opposite direction with respect to each other. Each output shaft is arranged to being directed towards the wheel axis for driving the wheel to which the output shaft is, in use, being connected, using known shafts and joints.

The first rotating machine M is arranged in front of the second rotating machine M', as seen from a side of the powertrain along a direction transverse to the output axes A2, A2'. This means that the first machine M is in use arranged more near to a front side Df of the vehicle C than a rear side Dc of the vehicle as shown e.g. in FIG 2. In other words, the first rotating axis A3 is, in use, offset towards a front side Df of the vehicle C with respect to the wheel axis Al and the second rotating axis A3' is, in use, offset towards a rear side Db of the vehicle C with respect to the wheel axis Al. The first rotating axis A3, second rotating axis A3' are parallel and offset with respect to the each other. The first rotating axis A3 and the second rotating axis A3' are mirror- symmetrically offset on opposite sides of the central axis AO. E.g., a plane can be imagined through the central axis AO wherein a placement of the first rotating axis A3 is mirrored in said plane by placement of the second rotating axis A3'. This arrangement can alternatively be described as having the first rotating axis A3 and the second rotating axis A3' at equal distances from the central axis AO, but on opposite sides of the central axis AO, e.g. one offset towards a front side of the vehicle and the other offset towards a rear side of the powertrain K. By the symmetrical configuration, a compact design can be provided and it can become possible to interchange the first and second transmissions T and T'.

Accordingly, in an embodiment, the first transmission T is interchangeable with the second transmission T'. In a further or alternative embodiment, the first rotating machine M is interchangeable with the second rotating machine M'. Interchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any assembly of the same type. One such part can freely replace another, without custom fitting or modification. This interchangeability allows easy assembly of new devices, and easier repair or replacement of existing devices, while minimizing both the time and skill required of the person doing the assembly or repair. In the shown embodiment, the first rotating axis A3, the second rotating axis A3', and the output axes A2, A2' are arranged parallel and offset in a triangular fashion in a side view Vs of the powertrain K as viewed along any of the parallel axes A3, A3', or A2, A2'. This triangular

configuration may provide an even more compact design. As can be seen in Fig. 6, the triangular configuration may result in a different triangle at either side of the powertrain K. While it is usually practical to have the machine axes A3,A3' offset towards a top side Dt of the vehicle, these can also be offset towards a bottom side, if there is enough clearance between the machines and the ground beneath the vehicle. In general, the

powertrain K can be tilted and/or rotated with respect to the vehicle C e.g. around the axis Al, provided there is enough clearance and space in the vehicle. Usually, the wheel axes Al, Al' of the pair of opposite wheels may be arranged lower with respect to the rotating axes A3, A3'. However, in embodiment where the powertrain is used in other apparatuses, not per se in a vehicle, the arrangement may be different. In a vehicle, the rotating machines typically may be electric machines. In apparatuses, other than a vehicle, the rotating machines may be electric machines, or hydraulic machines or pneumatic machines, or any other type of rotating machine.

In an embodiment, an axial position of the first rotating machine

M along a direction of the rotating axes A3, A3' at least partially overlaps with an axial position of the second rotating machine M'. By the at least partial overlap, a total width of the powertrain K as measured along the wheel axis Al can be reduced. With reference to FIG 2, by the arrangement of the first rotating machine M in front of the second rotating machine M', a width B of the machines Μ,Μ' installed in the vehicle C can be less than a sum of a width of the first machine M and a width of the second machine M', the widths measured along a direction of the first or second rotating axis A3, A3'. Ideally, to provide a compact design, positions of the first and second rotating machines along the axial direction of central axis AO fully overlap, i.e. the first machine is positioned fully in front or behind the second machine as viewed in a direction transverse to the direction of the central axis AO.

In the shown embodiment of FIG 1, the gear transmission of the transmission T comprises a plurality of gears Gl,G2,G3,G4 arranged for transmitting a torque of a machine shaft Si from a first machine M to an output shaft around an output axis A2. Rotational motion is initiated by providing controlled power to the machine M driving a rotating machine shaft Si. The machine shaft Si is connected to and/or engages a first gear Gl. The first gear Gl in use thus rotates together with the machine shaft

Si. The first gear Gl engages a second gear G2, imparting rotational motion to the second gear G2. Because in the shown embodiment, a radius of the second gear G2 is larger than that of the first gear Gl, an angular velocity of the second gear G2 will be lower than that of the first gear Gl while at the same time a higher torque of driving force is provided to the second gear G2. The second gear G2 is connected via a shaft to a third gear G3, that thus in use rotates with the second gear G2. The third gear G3 engages a fourth gear G4 having a smaller radius than G3. In this way again a reduction of the angular velocity and an increase of the torque is provided to the fourth gear G4. The fourth gear G4 is connected to or engages an output shaft S2 arranged on the output axis A2. The output shaft S2 may comprise e.g. a wheel bearing shaft or engage said wheel bearing shaft. When installed in a vehicle, the output shaft may thus impart rotational motion and torque to a wheel of the said vehicle, to put the vehicle in motion. While the present embodiments show a gear transmission using a number of gears that reduce the angular velocity between the machine shaft and the output shaft, also other gear configurations are possible. Instead of or in addition to using gear wheels, also belts, chains, or other mechanisms for transferring rotational motion can be used. While the powertrain K of the embodiment of FIG 2 is placed in front of the vehicle C to drive a pair of front wheels Wrf, Wlf, alternatively or in addition a powertrain K can be installed in the rear of the vehicle to drive a pair of rear wheels Wrb, Wlb.

FIG 3 shows a schematic top view Vt of parts forming an embodiment of a powertrain K comprising two powertrain modules Υ,Υ', wherein each powertrain module Υ,Υ' comprise at least one rotating machine Μ,Μ' and at least one transmissions Τ,Τ'. The Fig. 3 shows a transmission T for use in a powertrain K as described herein. The

transmission T comprises a gear transmission Gl,G2,G3,G4 arranged for transmitting torque of a first machine shaft Si of a first rotating machine M to a first output shaft S2. The transmission T further comprises a

transmission housing Z provided to house the gear transmission and to position and align rotating machines Μ,Μ'.

Advantageously, the two powertrain modules Υ,Υ' are identical which may be assembled in mirror inverted/imaged orientation in respect to the axis AO and wherein the rotating machine M of the first powertrain module Y may be received and/or engaged by the transmission housing of the second powertrain module Y' and vice versa. Mating structures

N1,N2,N1',N2' may be provided for assembling and/or mounting and/or fixating the first and second powertrain module Υ,Υ'. The first and second mating structures N1,N2 of the first powertrain module Y may be

assembled to respectively the first and second mating structures N1',N2' of the second powertrain module Y'. One or more second mating structures N2,N2' may be arranged in, on or as part of the transmission housing Ζ,Ζ'. These mating structures may be embodied as, but not limited to, holes, pins, bolts, protrusions, cavities, rims, shoulders or flanges comprising optionally additional connection elements like screw thread or magnetic elements. Mating structures N2,N2' may preferably arranged to receive respectively the first mating structures ΝΙ,ΝΙ'. These mating structure may be arranged on, in or as part of the rotating machines Μ,Μ' of the first and second powertrain module Υ,Υ', wherein the mating structures may be embodied as and not limited to pins holes, protrusions, cavities, rims or flanges, shoulders or any other connecting elements, comprising optionally additional connection elements like crew thread or magnetic elements.

Advantageously, the first mating structures ΝΙ,ΝΙ' may be embodied as a protrusion-, rim- or flange like protruding element Nib, Nlbl' on or as part of the rotating machines Μ,Μ' which protrudes concentrically in axial direction of the machine shafts Si, Si', wherein each end of the rotating machines Μ,Μ' comprise a rim Nla, Nla' on the outer periphery. Alternatively, the mating structure Nib, Nlbl' may comprise a cavity, ring shaped cavity, protrusions, holes or pins. The first mating structures ΝΙ,ΝΙ' may be received and/or engaged by one or more second mating structures N2,N2', wherein the mating structures N2, N2' preferably comprise a concentric protruding rim or a concentrically ring shaped cavity. So, the first mating structures ΝΙ,ΝΙ' comprise in principle elements of mirrored/negative configuration in respect of the second mating structures N2,N2'. Alternatively, the mating structures N2, N2' may comprise one or more holes, protrusions or pins which may be received and/or engaged by first mating structures ΝΙ,ΝΙ' with mirrored/negative mating structure elements.

Thus, the first mating structures ΝΙ,ΝΙ' of the first rotating and second rotating machines M, M' may be received and/or engaged by the second mating structures N2, N2' of the first and second transmission housings Z, Z' of respectively the first and second powertrain module Υ,Υ' in a fashion that the powertrain modules Υ,Υ' may be assembled and/or disassembled.

In the embodiment, the transmission T comprises an input side TA for engaging the respective machine shaft Si and an opposite output side TB for engaging the respective output shaft S2. In the shown embodiment, the second transmission T" has the same configuration.

Further, the transmission is provided with an input TI in which the rotating machine shaft Si can be received, and an output TO in which the output shaft S2 can be received. Also, the connection with the machine shaft Si and the output shaft S2 may be arranged in various ways.

In a further embodiment, the respective transmission T, in use, supports the first and second electric machines Μ,Μ' at the input side TA. By supporting the machines by means of one or both of the transmissions, a sturdy construction can be achieved. It will be appreciated that the compact design of the powertrain K in combination with the supporting function of the transmissions can further contribute to the overall structural integrity of the powertrain K.

The transmissions Τ,Τ' shown in this embodiment, comprises a third mating structure N3,N3' arranged for receiving and/or engaging a fourth mating structure N4,N4' of the first and second rotating machine Μ,Μ' for carrying the machine. Third mating structures N3,N3' may be integrated in the transmission housings Ζ,Ζ'. The third and fourth mating structures Ν3,Ν3' N4,N4' may be used to provide reliable support for the machines and hold the machines in a reproducible position. The mating structures N3,N3' on the transmission T can e.g. comprise a flange arranged for engaging a protrusion as mating structures N4,N4' on the rotating machines Μ,Μ'. The third and fourth mating structures N3, N3', N4, N4' are configured to mount the rotating machine M, M' to the transmission housing Z, Z'. Various embodiments of mating structures are possible.

The first and second transmissions Τ,Τ' shown in the embodiment comprises the second mating structures N2,N2' arranged for receiving and/or engaging a first mating structures ΝΙ,ΝΙ' of the first and second rotating machines Μ,Μ'. This second mating structure N2,N2' may be integrated or a separate element in or on the transmission housing Z. The first and second transmissions Τ,Τ' of the embodiment thus comprises a support structure for receiving and/or engaging two machines Μ,Μ'. The first and second transmission Τ,Τ' preferably is arranged to support the first and the second rotating machines M, M' at its input sides TA, TA'. At the output sides TB, TB' of the transmissions Τ,Τ', the output shafts S2,S2' of the gear transmission may be arranged, extending outwardly with respect to the powertrain towards the wheel to which the output shaft in use is connected. Although in another embodiment, the output shafts S2,S2' may be arranged at the input sides ΤΑ,ΤΑ', extending inwardly with respect to the powertrain and directed towards the wheel to which it is, in use, connected.

In an advantageous embodiment, the machines Μ,Μ' are sandwiched between two transmissions Τ,Τ' and carried by the

transmissions Τ,Τ', as can e.g. be seen in FIG 1, FIG 2 or FIG 3, wherein the transmission housing Z, Z' may be configured to house the transmission gears and to hold and align the machines M, M'. For example, in the present embodiment of FIG 3, the second transmission T" on the other side of the machines Μ,Μ' comprises similar mating structures, e.g. N2', as the first transmission T, arranged for receiving and/or engaging the machines Μ,Μ' from the other side. In one embodiment, the machines Μ,Μ' are

predominantly carried by the transmissions Τ,Τ'. This can save costs by omitting additional support structures. Also, additional specific components may be omitted, further reducing complexity and costs.

FIGs 4A and 4B show schematic top views Vt of embodiments of powertrains K. In these figures the gears Gl - G4 and Gl' - G4', are drawn more schematically. Also shown in these figures are some of the front bearings Bl, Β , and rear bearings B2, B2' that support the machine shaft SI.

In the embodiment of FIGs 4A and 4B, a front bearing Bl of the machine shaft Si on a side where the machine shaft Si engages the gears Gl,G2,G3,G4, is arranged in the transmission T housing said gears, e.g. comprised inside the transmission housing Z. By having a front bearing Bl, Bl' of the machine shaft Si, Si' inside the transmission T, T', demands on a bearing inside the machine M, M' can be lowered or the bearing inside the machine M, M' can be omitted. This can provide a more integrated design and save costs. E.g. if the front bearing Bl wears out, it can be replaced or repaired more easily without opening up the machine M. It will be

appreciated that especially the front bearing Bl on the side of the machine shaft Si engaging the gears can experience a significant load. Alternatively or in addition, as shown in the embodiment of FIG 4B, a front bearing Bl of a machine shaft Si is arranged in the first transmission T and a rear bearing B2 of said machine shaft Si is arranged in the second transmission T". This can further improve the integrated design and save costs.

In one embodiment, a front bearing Bl and/or a rear bearing B2 of the machine shaft Si is lubricated by a lubrication circuit (not shown) of a transmission T and/or T' housing said bearing. By providing lubrication wear of the bearing can be reduced. It will be appreciated that such lubrication can be more easily realized in the transmission T, e.g. having better accessibility than the machine M.

In a further advantageous embodiment, the lubrication circuit is shared by the front and/or rear bearing B1,B2 and the gear transmission Gl,G2,G3,G4 of the transmission T. Sharing the lubrication circuit, can provide a more compact design and/or save costs of separate lubrication. In an advantageous embodiment, the front bearing Bl and the gear

transmission Gl, G2, G3, G4 share the same lubrication circuit as they are housed in the transmission T. Lubrication of the front bearing Bl, in particular active lubrication as can be provided by the lubrication circuit, may be important as the front bearing Bl is subject to more heavy loading than the rear bearing B2. The rear bearing B2 may typically be provided with its own passive lubrication. In one embodiment, e.g. as shown in FIG 4A, a housing H of a machine M comprises an open end cap Ml passing the shaft Si, wherein a transmission T adjoining the machine M is arranged to close the end cap Ml with a housing plate Tl of the adjoining transmission housing Z. By closing an end cap of a machine M by means of the transmission housing Z, material costs of the machine end cap Ml can be saved while still providing a closure of the machine M from the environment. Also, the design of the powertrain can be more compact. Furthermore, the inside of the machine M can be more easily accessible when the transmission T is removed. In the embodiment of FIG 4A can be seen that the rear bearing B2 is housed inside the machine M.

In a further embodiment, e.g. as shown in FIG 4B, the machine M comprises an open end cap M2 also on the other side of the machine M passing the shaft Si, wherein the second transmission T" adjoining the machine M on that side is arranged to close the other end cap M2 with a housing plate T2 of the adjoining second transmission housing Z'. This can provide even further advantages, e.g. saving material cost. In the

embodiment of FIG 4B can be seen that the rotating shaft Slfrom the first motor M is extended to the second transmission T' such that the rear bearing B2 of the rotating shaft Si can be housed in the second

transmission T'. This can be advantageously be done when providing an open end cap at the rear side of the machine M.

FIG 5 shows a partial cut-out three-dimensional schematic top view Vt of another embodiment of a powertrain K. In this embodiment, the powertrain K is an electric powertrain comprising two electric machines M, M'. Some parts of the electric powertrain K as previously discussed are schematically drawn in the powertrain K. In particular, it is shown that the machine shaft Si is supported by a front bearing Bl and a rear bearing B2. The front bearing Bl is located in the transmission T and may be supported by the transmission housing Z. The machine shaft Si is kinematically connected via a gear transmission T to the output shaft S2 and may be supported by the transmission housing Z. Also shown in this figure are connections F that can be used for supplying a cooling fluid to the machine M. Further shown, is an electric connection E, arranged to provide electrical power and/or control signals to the respective electric machines M, M'.

Electrical power can e.g. be supplied to the machine from a battery (not shown).

In one embodiment, the transmission housing Z, Z' is manufactured from a plurality of moulded pieces. This can improve manufacturability. For example gears, bearings, and/or lubrication circuitry can be built into a first moulded piece of the housing and then closed off by a further moulded piece of the housing.

FIG 6 shows a further embodiment of the powertrain K according to the invention. The embodiment mainly corresponds with the embodiment shown in FIG 1 apart from the position of the output shafts S2, S2'. The output shafts S2, S2' are arranged on the output axis A2, A2' respectively. In this embodiment, the output axes A2, A2' are parallel to and offset with respect to the central axis AO. The output shafts S2, S2' are directed towards the wheel axes Al, Α of the pair of opposite wheels and are arranged to couple to the wheel to which they are, in use, connected, by means of known shafts and/or joints e.g. a homo-kinetic joint. Typically, the output shaft S2, S2' is therefore provided with at least one homo-kinetic joint. Also, in the embodiment according to FIG 6, the output shafts S2, S2' extend inwardly with respect to the powertrain K, typically extending underneath, or at a lower end of, the powertrain K towards the wheel to which they are, in use, connected.

The present disclosure relates to a powertrain (K) for driving a vehicle (C). The powertrain (K) comprises two rotating machines (Μ,Μ') and two transmissions (Τ,Τ'). The transmissions (Τ,Τ') are arranged to align their respective output shafts (S2,S2') towards a wheel axes (Al, Al') for driving a pair of opposite wheels of the vehicle (C), wherein the transmission may comprise transmission housings (Ζ,Ζ') to align and hold the machines Μ,Μ' and to form a barrier to e.g. dirt from the environment. The first rotating axis (A3), the second rotating axis (A3) and a central axis (AO) of the powertrain K are parallel and offset with respect to the each other and the first rotating axis (A3) and the second rotating axis (A3') are mirror- symmetrically offset on opposite sides of the central axis (AO). In this way a compact and versatile design is achieved.

The above described example embodiments show a gear transmission comprising gears as torque transmitting elements. Of course, the torque transmitting elements may be a chain drive or a belt drive or other torque transmitting elements or a combination thereof.

While example embodiments were shown for a rotating powertrain, also alternative ways may be envisaged by those skilled in the art having the benefit of the present disclosure for achieving a similar function and result. E.g. shafts or gears may be combined or split up into one or more alternative components. The various elements of the

embodiments as discussed and shown offer certain advantages, such as providing a compact and modular design. Of course, it is to be appreciated that any one of the above embodiments or processes may be combined with one or more other embodiments or processes to provide even further improvements in finding and matching designs and advantages. E.g.

technical features and advantages of the transmission described in connection with the powertrain can also be considered separate from the described powertrain, e.g. in combination with a powertrain of different design. It is appreciated that this disclosure offers particular advantages to powertrains having two or more rotating machines but may also benefit a powertrain with one machine that is carried by one or two transmissions and/or is partly closed off by an adjoining housing of the transmission and/or comprises a machine shaft bearing inside an adjoining transmission. While the present systems and methods have been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the scope of the present disclosure. The above- discussion is intended to be merely illustrative of the present systems and/or methods and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims. In interpreting the appended claims, it should be understood that the word "comprising" does not exclude the presence of other elements or acts than those listed in a given claim; the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; any reference signs in the claims do not limit their scope; several "means" may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. In particular, all working combinations of the claims are considered inherently disclosed.

Claims

1. Powertrain (K) for driving a vehicle (C), the powertrain (K) comprising

- a first powertrain module (Y)comprising

o a first rotating machine (M), comprising a first machine shaft (Si) arranged to be rotationally driven by the first rotating machine (M) for providing a torque to the first machine shaft (Si) around a first rotating axis (A3);

o a first transmission (T), comprising first torque transmitting

elements (Gl,G2,G3,G4) arranged for transmitting the torque of the first machine shaft (Si) to a first output shaft (S2), wherein the first output shaft (S2) has an output direction opposite to that of a second output shaft (S2') , wherein the first torque transmitting elements (Gl,G2,G3,G4) are housed in a first transmission housing (Z);

- a second powertrain module (Υ') comprising

o a second rotating machine (Μ'), comprising a second machine shaft (Si') arranged to be rotationally driven by the second machine (Μ') for providing a torque to the second machine shaft (Si') around a second rotating axis (A3');

o a second transmission (Τ'), comprising second torque transmitting elements (Gl',G2',G3',G4') arranged for transmitting the torque of the second machine shaft (Si') to the second output shaft (S2'), wherein the first output shaft (S2) has an output direction opposite to that of the second output shaft (S2'), wherein the second torque transmitting elements (Gl',G2',G3',G4') are housed in a second transmission housing Z';

• wherein the first and second output shafts (S2,S2') of respectively the first and second powertrain modules (M, M') are arranged on a first and second output axis (A2, A2') to direct the first and second output shafts (S2, S2') towards wheel axes (Al, Α ) for driving a pair of opposite wheels (Wlb,Wrb; Wlf,Wrf) of the vehicle (C);

• wherein the first rotating machine (M) is arranged in front of the second rotating machine (M');

· wherein the first rotating axis (A3) and the second rotating axis

(A3') are parallel and offset with respect to the each other;

2. Powertrain (K) according to claim 1, wherein an axial position of the first rotating machine (M) along a direction of the rotating axis (A3) at least partially overlaps with an axial position of the second rotating machine (Μ') for reducing a total width of the powertrain as measured in a direction of the rotating axes (A3, A3').

3. Powertrain (K) according to claim 1 or 2, wherein the first and second output axis (A2, A2') coincide with each other, such that the first and second output shafts (S2, S2') are aligned with each other.

4. Powertrain (K) according to any of the preceding claims, wherein the first and second output axis (A2, A2') are parallel to and offset with respect to each other such that the first and second output shafts (S2, S2') are offset with respect to each other.

5. Powertrain (K) according to any one of the previous claims, wherein the first and second output shafts (S2, S2') comprise a homo-kinetic joint for direction towards the wheel axes (Al, Α ) allowing suspension movement and vehicle turning.

6. Powertrain (K) according to any of the previous claims, wherein a transmission (T, T") of said first and second transmissions (Τ,Τ') comprises an input side (TA, TA^*) for engaging the respective first or second machine shaft (Si, Si') and an opposite output side (TB, TB') for engaging the respective first or second output shaft (S2, S2').

7. Powertrain (K) according to claim 6, wherein the transmission (T, T") supports the first and second rotating machines (Μ,Μ') at its input side (TA, TA') respectively.

8. Powertrain (K) according to any of the previous claims, wherein the transmission (T, T") comprises a third mating structure (N3, N3') arranged for receiving and/or engaging a fourth second mating structure (N4, N4') of the rotating machine (M, M') for carrying the rotating machine (M, M').

9. Powertrain (K) according to any of the previous claims, wherein third mating structure (N3, N3') are provided in the transmission housing (Z, Z').

10. Powertrain (K) according to any of the previous claims, wherein the first transmission housing (Z) is interchangeable with the second transmission housing (Ζ')

11. Powertrain (K) according to any of the previous claims, wherein the first transmission (T) is interchangeable with the second transmission ( ').

12. Powertrain (K) according to any of the previous claims, wherein the first rotating machine (M) is interchangeable with the second rotating machine (Μ')

13. Powertrain (K) according to any of the previous claims, wherein the first rotating axis (A3), the second rotating axis (A3'), and the output axes (A2, A2') are arranged parallel and offset in a triangular fashion in a side view (V s) of the powertrain (K) as viewed along the rotating axes (Α3,Α3').

14. Powertrain (K) according to any of the previous claims, wherein the machines (Μ,Μ') are sandwiched between the transmissions (Τ,Τ') and carried by the transmissions (Τ,Τ').

15. Powertrain (K) according to any of the previous claims, wherein a first and second front bearing (Bl, Bl') of the first and second machine shaft (Si, Si') respectively on a side where the first and second machine shaft (Si, Si') engages the first and second torque transmitting elements

(G1,G2,G3,G4; Gl', G2', G3', G4') respectively is arranged inside the first and second transmission housing (Z, Z') respectively housing the first and second torque transmitting elements (Gl,G2,G3,G4; Gl', G2', G3', G4') respectively.

16. Powertrain (K) according to any of the previous claims, wherein a first and second rear bearing (B2, B2') of the first and second machine shaft

(Si, Si') respectively on a side, opposite the side where the first and second machine shaft (Si, Si') engages the first and second torque transmitting elements (Gl, G2, G3, G4, Gl', G2', G3', G4') respectively, is arranged inside the second and first transmission housing (Z", Z) respectively housing the second and first torque transmitting elements (Gl', G2', G3', G4', Gl, G2, G3, G4) respectively.

17. Powertrain (K) according to claim 15 or 16, wherein the front bearing (Bl, Bl') of the machine shaft (Si, Si') is lubricated by a lubrication circuit of a transmission (T, T") housing said front bearing (Bl, Bl').

18. Powertrain (K) according to claim 17, wherein the lubrication circuit is shared by the front bearing (Bl, Bl') and the torque transmitting elements (Gl,G2,G3,G4, Gl', G2', G3', G4') of the transmission (T, T').

19. Powertrain (K) according to any of the previous claims, wherein a housing (H) of the first and/or second machine (M, M comprises an open end cap (M1,M2, Ml', M2') passing the machine shaft (Si, Si'), wherein a transmission (Τ,Τ') adjoining the machine (M, M') is arranged to close the end cap (M1,M2, Ml', M2') with a housing plate (T1,T2, Ί , T2') of the adjoining transmission (Τ,Τ').

20. Powertrain (K) according to any of the previous claims, wherein the transmission housing (Z, Z') is manufactured from one or a plurality of moulded pieces.

21. Powertrain (K) according to any of the previous claims, wherein the torque transmitting elements between the machine shaft (Si, Si') and the output shaft (S2, S2') comprises one set of gears (Gl, G2, Gl', G2').

22. Powertrain (K) according to any one of the previous claims, wherein the rotating machine is one of an electric machine or a hydraulic machine, or a pneumatic machine.

23. Powertrain (K) according to any of the previous claims, wherein the first powertrain module (Υ') comprises a first mating structure (Nl) and a second mating structure (N2) for engagement with the first and second mating structures (NT, N2') of the second powertrain module (Υ').

24. Transmission (T, T") for use in a powertrain (K) according to any of the previous claims, the transmission (T, T") comprising

o torque transmitting elements (Gl,G2,G3,G4, Gl', G2', G3', G4')

arranged for transmitting torque of a first machine shaft (Si, Si') of a first rotating machine to a first output shaft (S2, S2'), wherein the torque transmitting elements (Gl,Gl',G2,G2',G3,G3',G4,G4') are housed in a transmission housing (Ζ,Ζ');

- wherein the transmission (T, T") comprises an input side (TA, TA') for engaging the first machine shaft (Si, Si') and an opposite output side (TB, TB') for engaging the first output shaft (S2, S2'); wherein the transmission (T, T") supports the first rotating machine (M, M') and a second rotating machine (Μ', M) at the input side (TA, TA').

25. Vehicle (C) comprising a powertrain (K) according to any of the claims 1 - 23, and/or a transmission (T) according to claim 24.

26. Apparatus comprising a powertrain (K) according to any of the claims 1 - 23 and/or a transmission (T) according to claim 24.