Electrically operated powertrain and vehicle

Abstract

Electrically operated drive train (10), comprising a first transfer case (11), a first electric motor (12) and a first axle (13, 13') as well as a second transfer case (14), a second electric motor (15, 15') and a second axle (16, 16'), wherein the first transfer case (11) has a first input (17), a first axle output (18) and a first coupling output (19), wherein the second transfer case (14) has a second input (20), a second axle output (21) and a second coupling output (22) and wherein the first coupling output (19) can be coupled to the second coupling output (22) via a coupling shaft (23), wherein the first transfer case (11) further comprises a first auxiliary output (24), characterized in thatthat the first axle output (18) and the first coupling output (19) have an identical speed reduction relative to the first input (17), and that the second axle output (21) and the second coupling output (22) have the same identical speed reduction relative to the second input (20).

Description

The present invention relates to an electrically operable drive train according to the preamble of claim 1 and to a corresponding vehicle.Various types of electrically driven commercial vehicles, such as wheel loaders, trucks, mine vehicles or vehicles used for transporting luggage at airports, are already known in the prior art. These electrically driven utility vehicles are either driven purely electrically, i.e. they have exclusively an electric battery or an electric accumulator for their energy supply, or they are driven diesel-electrically, which means that the required energy is provided by a diesel-driven generator, usually in conjunction with an electrical buffer store, such as a correspondingly dimensioned capacitor. In all cases, the mechanical power required for the traction drive or the work drive is produced by one or more electric motors.In this context, DE 10 133 815 A1 discloses a mobile aircraft loading device having a frame, a main platform which is vertically mobile relative to the frame and a front platform which is vertically mobile relative to the frame and dockable on the aircraft, and force means for independently raising and lowering the platforms. The aircraft loading device of DE 10 133 815 A1 has an electric drive.DE 20 2016 006 076 U1 discloses a trailer for an electrically operated truck, which has at least one cutout for receiving one or more battery packs in each case.DE 10 2018 206 411 A1 discloses a drive train for a work machine, which has a front axle with an electric front axle drive unit and a rear axle with an electric rear axle drive unit. Furthermore, the drive train has a switchable clutch which can drive-connect the front axle drive unit to the rear axle drive unit.DE 11 2004 002 494 B4 discloses a hybrid transmission having an input element for receiving power from an internal combustion engine, an output element for outputting power from the hybrid transmission, a first and second motor / generator, an energy storage device for exchanging electrical power with the first and second motor / generator and a first, second and third planetary gear set.DE 10 2019 214 202 A1 discloses an electric drive for tractors. The drive comprises a first drive train, wherein the first drive train has a power take-off for driving an attachment that can be coupled, or a pump power take-off for driving at least one hydraulic pump. The drive also comprises a second drive train, wherein the second drive train has a vehicle transmission, wherein the vehicle transmission has at least one transmission output for driving at least one vehicle axle. Finally, the drive also comprises a first and a second electric machine, wherein the first electric machine is drive-coupleable to the first drive train and the second electric machine is drive-coupleable to the second drive train.DE 10 2018 221 603 A1 describes a drive axle of an electrically drivable vehicle, comprising two electric machines, two drivable vehicle wheels, an axle differential and a transmission. The transmission has a first drive train between the first electric machine and the axle differential and a second drive train between the second electric machine and the axle differential. The first drive train and the second drive train have different transmission ratios between the first electric machine and the axle differential as well as between the second electric machine and the axle differential.DE 10 2005 044 179 A1 discloses a drive system for an agricultural or industrial utility vehicle. The propulsion system includes a mechanical torque-generating propulsion assembly, first, second, and third electric machines, a first mechanical output interface for propelling at least one vehicle axle, and a second mechanical output interface. A shaft driven by the drive assembly is in rotational communication with the shaft of the first electric machine. With the second output interface, a working device that can be coupled to the commercial vehicle can be operated mechanically. The shaft of the second electric machine or the shaft of the third electric machine can be connected reversibly to the first mechanical output interface.However, the known electrically operable drive trains are disadvantageous in that the different electric motors are provided exclusively for propelling the working machine or the vehicle, even if in certain situations only one of the electric motors is required for propulsion.It is an object of the invention to propose an improved electrically operable drive train.This object is achieved according to the invention by the electrically operable drive train according to claim 1. Advantageous embodiments and further developments of the invention are evident from the dependent claims.The invention relates to an electrically operable drive train comprising a first transfer case, a first electric motor and a first axle as well as a second transfer case, a second electric motor and a second axle, wherein the first transfer case has a first input, a first axle output and a first coupling output, wherein the second transfer case has a second input, a second axle output and a second coupling output and wherein the first coupling output can be coupled to the second coupling output via a coupling shaft. The drive train according to the invention is characterized in that the first transfer case also has a first auxiliary output.The invention thus describes an electrically operable drive train. The drive train is designed in particular to drive a terrain-accessible working machine, a terrain-accessible special vehicle such as, for example, a crane or wheel armour or an all-wheel-driven truck, which means that it must be designed for continuous operation with very high powers in comparison with those in passenger car operation or also in truck operation. An electric drive train of a passenger car would not be suitable for this purpose, for example.The drive train according to the invention comprises a first transfer case, to which a first electric motor and a first axle are assigned. The first electric motor provides a torque and a rotational speed which can be introduced into the first transfer case via the first input and are converted by the first transfer case in order then to be able to be continued to the first axis via the first axle output for driving the first axle.The drive train according to the invention further comprises a second transfer case, to which a second electric motor and a second axle are assigned. The second electric motor also provides a torque and a rotational speed which can be introduced into the second transfer case via the second input and which are converted by the second transfer case in order to be able to be continued to the second axis in order to drive the second axis.In addition, the first transfer case and the second transfer case each have a coupling output. The first coupling output of the first transfer case can be coupled to the coupling shaft in the same way as the second coupling output of the second transfer case. Thus, a drive connection can be established between the first transfer case and the second transfer case via the coupling shaft in the coupled state. This allows, for example, the transmission of drive power from the first electric motor to the second axis or from the second electric motor to the first axis. If drive power is to be transmitted from the first electric motor to the second axle, the first axle is advantageously blocked. Conversely, the second axle is advantageously blocked if drive power is to be transmitted from the second electric motor to the first axle. Thus, a full-quality and in particular lockable all-wheel drive can be provided via the first and second coupling output and the coupling shaft. If, namely, slip occurs on one of the two axles, the drive power of the associated electric motor can nevertheless be used for propulsion by locking the corresponding axle, so that the drive power is passed on to the axle which does not experience slip. Since the drive power of the first and the second electric motor can thus be coupled, it is advantageously possible to dispense with using two correspondingly more powerful, heavier and more expensive electric motors, which could in each case also individually provide the maximum drive power.According to the invention, it is now provided that the first transfer case also has a first auxiliary output. The drive train according to the invention thus differs from drive trains of the generic type known from the prior art in that the first transfer case with the first electric motor assigned to it not only drives the first axle, but can also drive an auxiliary output drive. The first electric motor can thus drive both the first axle and the first auxiliary power take-off, which results in the advantage that-compared to the prior art-no additional electric motor has to be provided in order to drive an auxiliary power take-off. For example, the first electric motor can drive the first axle and the first auxiliary power take-off simultaneously or drive only the first auxiliary power take-off or only the first axle depending on the situation or according to a corresponding driver specification. If the first electric motor drives only the first auxiliary power take-off, the auxiliary power take-off can be operated completely independently of the rotational speed. During this, the second electric motor can drive the second axle, for example, and thus provide the required propulsion for a movement of the vehicle.When a vehicle having the drive train according to the invention is at a standstill, the auxiliary power take-off can thus be operated completely independently of the driving operation. Likewise, the auxiliary power take-off can always be operated independently of the drive drive if the second electric motor alone can provide sufficient drive power for the drive operation. However, if the first electric motor is required for the driving operation in addition to the second electric motor, the auxiliary power take-off can only be operated at an engine speed of the first electric motor which is predetermined by the driving operation.The first and the second transfer case are therefore at least functionally identical, but in particular even completely identical in construction, i.e. the first and the second transfer case are identically constructed gears.The first and the second transfer case are preferably each designed as a shiftable and at least two-stage transmission, so that a suitable transmission ratio of the torque provided by the first or second electric motor and introduced into the transmission as well as the rotational speed provided by the first or second electric motor and introduced into the transmission can be set as required.Preferably, the first and the second transfer gear are each designed as spur gear transmissions.Likewise, the first and the second electric motor can also be electric motors of identical construction.The first and the second electric motor can each be designed as a synchronous machine or as an asynchronous machine, in particular as a three-phase synchronous machine or as a three-phase asynchronous machine.The first and the second electric motor are each advantageously assigned an inverter which converts electrical direct current, which is preferably provided by an electric battery, into alternating current suitable for controlling or operating the first or second electric motor.The first axle can be advantageously designed, for example, as a steerable driven axle and the second axle can be designed, for example, as a non-steerable driven axle. Likewise, conversely, the second axle can also be configured as a steerable driven axle and the first axle as a non-steerable driven axle.According to a preferred embodiment of the invention, it is provided that the first axle output can be coupled to the first electric motor via a first axle output coupling element, that the first auxiliary output can be coupled to the first electric motor via a first auxiliary output coupling element, that the first coupling output can be coupled to the first electric motor via a first coupling output coupling element, that the second axle output can be coupled to the second electric motor via a second axle output coupling element, and that the second coupling output can be coupled to the second electric motor via a second coupling output coupling element. Thus, the mentioned elements can be drivingly connected to the first or second electric motor, respectively, if necessary, and can be decoupled again. Advantageously, each of the mentioned elements is also assigned a brake in order to fix the respective element and to avoid an unwanted, possibly creeping, rotation. In particular, the coupling shaft can also be stopped completely by decoupling it from both the first electric motor and the second electric motor, so that it does not generate any drag torque during driving operation.According to a further preferred embodiment of the invention, it is provided that the second transfer case also has a second auxiliary power take-off, wherein the second auxiliary power take-off can be coupled to the second electric motor via a second auxiliary power take-off coupling element. Thus, with the second auxiliary power take-off, a further auxiliary power take-off is available, which can be used additionally or alternatively to the first auxiliary power take-off and in a manner analogous to the first auxiliary power take-off.According to a particularly preferred embodiment of the invention, it is provided that the first coupling output coupling element is arranged in the first transfer case and the second coupling output coupling element is arranged in the second transfer case. An arrangement in the first or second transfer case is understood to mean that the first coupling output coupling element is housed by a housing of the first transfer case and that the second coupling output coupling element is housed by a housing of the second transfer case. This results in the advantage that no further coupling elements each having its own housing have to be provided. Installation space can thus be saved.According to the invention, it is provided that the first axle output and the first coupling output have an identical speed reduction compared to the first input and that the second axle output and the second coupling output have the same identical speed reduction compared to the second input. This simplifies the construction of the transfer gears and the transmission of drive power between the first transfer gear and the second transfer gear equally.According to a further preferred embodiment of the invention, it is provided that a plurality of first axles are assigned to the first transfer case. For this purpose, the first axles advantageously have a through-drive, so that the drive power can be distributed over all first axles. The drives of the individual axles can advantageously also be assigned locks in order to lock one or more drives. All first axles are supplied with drive power by the first electric motor via the first transfer gear.According to a further preferred embodiment of the invention, it is provided that a plurality of second axles are assigned to the second transfer case. The second axles also advantageously have a through drive, so that the drive power of the second electric motor can be distributed accordingly to all the second axles. Locks can also be advantageously assigned to the drives of the second axles in order to lock one or more drives. All second axles are supplied with drive power by the second electric motor via the second transfer gear.According to a further preferred embodiment of the invention, it is provided that the first auxiliary power take-off is drive-connected to an additional first electric motor. In this case, the first auxiliary power take-off is thus used as an additional drive, via which the additional first electric motor can introduce additional drive power into the first transfer case. Thus, the drive power that can be provided via the first transfer case can be increased in a simple manner.According to a further preferred embodiment of the invention, it is provided that the second auxiliary power take-off is drive-connected to an additional second electric motor. Just like the first auxiliary power take-off, additionally or alternatively the second auxiliary power take-off can also be drive-connected to an additional second electric motor. Accordingly, the drive power which can be provided via the second transfer gear can thereby be increased.The invention further relates to a vehicle comprising a drive train according to the invention. This also results in the advantages already described for the vehicle according to the invention.The vehicle is preferably a off-road working machine, a crane, an all-wheel drive truck, a wheel armour or an off-road special vehicle.In particular, it is provided that the working machine is designed as a wheel loader, dumper, excavator, telescopic loader or tractor.The invention is explained below by way of example with reference to embodiments shown in the figures.The following are shown: FIG. 1 shows, by way of example and schematically, a possible embodiment of an electrically operable drive train according to the invention, FIG. 2 shows, by way of example and schematically, a further possible embodiment of an electrically operable drive train according to the invention, and FIG. 3 shows, by way of example and schematically, yet another possible embodiment of an electrically operable drive train according to the invention.Identical items, functional units and comparable components are denoted by the same reference numerals across the figures. These objects, functional units and comparable components are identical in terms of their technical features, unless the description explicitly or implicitly reveals otherwise.FIG. 1 shows, by way of example and schematically, a possible embodiment of an electrically operable drive train 10 according to the invention. The drive train 10 comprises a first transfer case 11, a first electric motor 12 and a first axle 13 and also a second transfer case 14, a second electric motor 15 and a second axle 16.The first transfer case has a first input 17, a first axle output 18 and a first coupling output 19. Correspondingly, the second transfer case 14 has a second input 20, a second axle output 21 and a second coupling output 22. The first coupling output 19 and the second coupling output 22 are coupled via a coupling shaft 23.As can also be seen, the first transfer case 11 has a first auxiliary drive 24, by means of which, according to the example, a mechanical auxiliary consumer 25 is driven.The first transfer case 11 enables the first axle output 18 to be coupled or decoupled to the first electric motor 12 via a first axle output coupling element (not shown in FIG. 1 ). Likewise, the first transfer case 11 enables the first auxiliary output 24 to be coupled or decoupled with the first electric motor 12 via a first auxiliary output coupling element (not shown in FIG. 1 ) and the first coupling output 19 to be coupled or decoupled with the first electric motor 12 via a first coupling output coupling element (not shown in FIG. 1 ). The first coupling output coupling element is arranged here, according to the example, in the housing of the first transfer case 11.The first axle output 18 and the first coupling output 19 have an identical speed reduction compared to the first input 17 according to the example.In an analogous manner, the second transfer case 14 makes it possible for the second axle output 21 to be coupled or uncoupled to the second electric motor 15 via a second axle output coupling element (not shown in FIG. 1 ) and for the second coupling output 22 to be coupled or uncoupled to the second electric motor 15 via a second coupling output coupling element (not shown in FIG. 1 ). The second coupling output coupling element is arranged here, according to the example, in the housing of the second transfer case 14.The second axle output 21 and the second coupling output 22 have an identical speed reduction compared to the second input 20 according to the example. According to the example, this speed reduction is also identical to the speed reduction of the first coupling output 19 or of the first axle output 18 with respect to the first input 17.By virtue of the fact that the first coupling output 19 and the second coupling output 22 can be decoupled from the first electric motor 12 and from the second electric motor 15, respectively, the coupling shaft 23 can be switched in a drive-free manner. Thus, during operation of the first transfer case 11 and the second transfer case 14, the coupling shaft 23 does not generate drag torque when the first and second coupling output coupling elements are released.However, if the first and the second coupling output coupling elements are closed, driving power can be conducted as required from the first electric motor 12 to the second transfer case 14 and vice versa from the second electric motor 15 to the first transfer case 11. Thus, for example, if excessive slipping of the first axle is detected, the first axle 13 may be locked via the first axle output coupling element. The drive power of the first electric motor 12 is then provided via the coupling shaft 23 and the second transfer case 14 for driving the second axle 16.FIG. 2 shows, by way of example and schematically, a further possible embodiment of an electrically operable drive train 10 according to the invention. The drive train 10 of FIG. 2 differs from the drive train 10 of FIG. 1 in that two second axles 16, 16' are assigned to the second transfer case 14, both of which axles are driven via the second axle output 21.FIG. 3 shows, by way of example and schematically, yet another possible embodiment of an electrically operable drive train 10 according to the invention. The drive train 10 of FIG. 3 differs from the drive train 10 of FIG. 2 in that two first axles 13, 13' are also assigned to the first transfer case 11, both of which axles are driven accordingly via the first axle output 18.In addition, the drive train 10 of FIG. 3 has a second auxiliary output 26 on the second transfer case, wherein the second auxiliary output 26 can be coupled to the second electric motor 15 via a second auxiliary output coupling element (not shown in FIG. 3 ). According to the example, however, no auxiliary consumer 25 is drive-connected to the second auxiliary output drive 26, but rather an additional second electric motor 15' which can drive additional drive power into the second transfer case 14 via the second auxiliary output drive 26. The second auxiliary power take-off 26 is therefore used according to the example an additional drive into the second transfer case 14.Reference numerals denote reference numerals10 Drive train 11 First transfer case 12 First electric motor 13, 13' First axle 14 Second transfer case 15, 15' Second electric motor 16, 16' Second axle 17 First drive 17' Track lever, steering linkage 17" Steering lever, steering linkage 18 First axle output 19 First coupling output 20 Second drive 21 Second axle output 22 Second coupling output 23 Coupling shaft 24 First auxiliary output 25 Auxiliary consumer 26 Second auxiliary output

Claims

Electrically operable drive train (10) comprising a first transfer case (11), a first electric motor (12) and a first axle (13, 13') as well as a second transfer case (14), a second electric motor (15, 15') and a second axle (16, 16'), wherein the first transfer case (11) has a first input (17), a first axle output (18) and a first coupling output (19), wherein the second transfer case (14) has a second input (20), a second axle output (21) and a second coupling output (22) and wherein the first coupling output (19) can be coupled to the second coupling output (22) via a coupling shaft (23), wherein the first transfer case (11) furthermore has a first auxiliary output (24), characterized in that, the first axle output (18) and the first coupling output (19) have an identical speed reduction compared to the first input (17), and the second axle output (21) and the second coupling output (22) have the same identical speed reduction compared to the second input (20).Drive train (10) according to Claim 1, characterized in that the first axle output (18) can be coupled to the first electric motor (12) via a first axle output coupling element, in that the first auxiliary output (17) can be coupled to the first electric motor (12) via a first auxiliary output coupling element, in that the first coupling output (19) can be coupled to the first electric motor (12) via a first coupling output coupling element, in that the second axle output (21) can be coupled to the second electric motor (15, 15') via a second axle output coupling element, and in that the second coupling output (22) can be coupled to the second electric motor (15, 15') via a second coupling output coupling element.Drive train (10) according to at least one of Claims 1 and 2, characterized in that the second transfer case (14) furthermore has a second auxiliary output (26), wherein the second auxiliary output (26) can be coupled to the second electric motor (15, 15') via a second auxiliary output coupling element.Drive train (10) according to Claim 3, characterized in that the first coupling output coupling element is arranged in the first transfer case (11) and the second coupling output coupling element is arranged in the second transfer case (14).Drive train (10) according to at least one of Claims 1 to 4, characterized in that a plurality of first axles (13, 13') are assigned to the first transfer case (11).Drive train (10) according to at least one of Claims 1 to 5, characterized in that a plurality of second axles (16, 16') are assigned to the second transfer case (14).Drive train (10) according to at least one of Claims 1 to 6, characterized in that the first auxiliary power take-off (24) is drive-connected to an additional first electric motor.Drive train (10) according to at least one of Claims 1 to 7, characterized in that the second auxiliary power take-off (26) is drive-connected to an additional second electric motor (15').Vehicle comprising a drive train (10) according to at least one of claims 1 to 8.

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