DE102022204747A1 - Drive device for a work machine - Google Patents

Abstract

The invention relates to a drive device (10) for a work machine, wherein the drive device (10) has a first electric machine (EM1) with a first motor shaft (12), a second electric machine (EM2) with a second motor shaft (14), a first travel output shaft ( 16), a first PTO shaft (40) and a second PTO shaft (42). The first motor shaft (12) can be mechanically operatively connected to the first travel output shaft (16) by means of a travel gear (32). The second motor shaft (14) can be mechanically connected to the two PTO shafts (40, 42). An output shaft (36) of the drive transmission (32) is permanently connected in a rotationally fixed manner to the first drive output shaft (16). An input shaft (34) of the travel gear (32) is mechanically operatively connected to the first motor shaft (12). The input shaft (34) of the transmission (32) can be mechanically connected to the output shaft (36) via a first spur gear stage (FST1). The input shaft (34) of the travel gear (32) can be connected in a rotationally fixed manner to an intermediate shaft (38) of the travel gear (32). The intermediate shaft (38) can be mechanically operatively connected to the output shaft (36) of the travel gear (32) via a second travel spur gear stage (FST2) or a third travel spur gear stage (FST3). The invention also relates to a work machine.

Description

Technical area

The present invention relates to a drive device for a work machine, which has two electric machines.

State of the art

Drive devices for work machines must enable efficient and reliable operation of the work machine under different ground conditions and work cycles. If the machine is driven purely by an internal combustion engine, complex, expensive and large mechanical and alternatively or additionally hydraulic components are necessary.

Presentation of the invention

A first aspect of the invention relates to a drive device for a work machine. A drive device can, for example, form part of a drive train. The work machine can be used as an agricultural machine, e.g. B. be designed as a tractor, as a construction machine or as a special vehicle. Examples of a work machine are a wheel loader and a tractor, in which the respective wheels can be driven by drive power from the drive device. Attachments can usually be mounted on work machines, which can also be driven by the work machine. The work machine can provide a power tap for this purpose.

The drive device has a first electric machine with a first motor shaft. The first electric machine is designed to provide a first drive power on the first motor shaft. The drive device has a second electric machine with a second motor shaft. The second electric machine is designed to provide a second drive power on the second motor shaft. Each of the electric machines has, for example, only one motor shaft. The designation as the second motor shaft serves to assign it to the second electric machine.

The electric machines can be designed to convert electrical energy into mechanical energy. Optionally, the electric machines can each be designed for recuperation. An electric machine can be designed, for example, as an asynchronous motor or synchronous motor. For example, the drive device has a power source, such as a rechargeable battery. The energy source can be used to supply the two electric machines with electricity for their operation. The drive device can have an associated inverter for each electric machine, which controls a drive power output of the electric machine. Each electric machine of the drive device can also have an associated energy source.

The drive device has a first drive output shaft. For example, part of the drive power generated by the electric motors can be output on the first drive output shaft, for example to an assigned drive axle of the work machine. The first travel output shaft can, for example, be mechanically operatively connected to a rear axle of the work machine. A travel output shaft can, for example, be mechanically operatively connected to the associated drive axle of the work machine via an axle differential. Alternatively or additionally, for example, a mechanical active connection via respective bevel gears is also possible. A travel output shaft can form an output shaft of the drive device. The drive device can be designed to transmit drive power from the first motor shaft to the first drive output shaft.

The first motor shaft can be mechanically operatively connected to the first drive output shaft by means of a drive gear. The drive device can have the driving gear. The drive transmission can be designed to provide different ratios between the first motor shaft and the first drive output shaft. The drive transmission can also be designed to interrupt torque transmission from the first motor shaft to the first drive output shaft, for example in the event of a specific switching state. This can provide an idle.

The drive device has a first PTO shaft and a second PTO shaft. Power take-off can be provided on a PTO shaft. The first PTO shaft can be designed, for example, as a front PTO shaft. The second PTO shaft can be designed as a rear PTO shaft. For example, attachments can be supplied with mechanical power from the work machine on each PTO shaft. The drive device can, for example, be designed to drive the PTO shaft at a substantially constant speed, for example one of two predetermined PTO shaft speeds. The drive device can alternatively or additionally be designed, for example, to drive the PTO shaft at variable speeds. The drive device can be designed to selectively separate a drive power transmission to one of the two or both PTO shafts.

The second motor shaft can be mechanically operatively connected to the first PTO shaft and to the second PTO shaft. For example, in a first switching state, the second motor shaft can only be mechanically operatively connected to the first PTO shaft. For example, in a second switching state, the second motor shaft can only be mechanically operatively connected to the second PTO shaft. For example, the second motor shaft can be mechanically operatively connected to the first PTO shaft and the second PTO shaft in a third switching state. For example, in a fourth switching state, the second motor shaft can not be mechanically operatively connected to either of the two PTO shafts. In the fourth switching state, the second electric machine can drive auxiliary units such as hydraulic pumps without driving an attachment or one of the two PTO shafts. In the fourth switching state, in certain embodiments, the second electric machine can alternatively or additionally drive a travel drive shaft without driving an attachment.

The drive device can take advantage of the fact that electric machines can allow a more flexible use of the installation space of the work machine compared to a drive device only with an internal combustion engine. This means that the work machine can now have two PTO shafts, with only one or both PTO shafts being driven during operation. This makes it possible to use or at least attach two attachments at the same time. For example, the two attachments are only driven by the second electric machine. So, even if the mechanical structure is largely the same compared to a work machine with only an internal combustion engine, no additional motor needs to be provided to drive the second PTO shaft. There may be an additional power interface for the second PTO. The drive of the two PTO shafts can be integrated into a central drive.

The transmission has an input shaft, an output shaft, a first travel gear stage, a second travel spur gear stage, a third travel spur gear stage, a first travel shift element, a second travel shift element, a third travel shift element, a fourth travel shift element and an intermediate shaft. The output shaft of the drive transmission is permanently connected in a rotationally fixed manner to the first drive output shaft. The input shaft of the transmission is mechanically connected to the first motor shaft. For example, the input shaft of the transmission can be permanently connected in a rotationally fixed manner to the first motor shaft or can be mechanically operatively connected via a spur gear stage. The input shaft of the driving gear can be mechanically operatively connected to the output shaft via the first driving spur gear stage by means of the first driving switching element. The input shaft of the drive transmission can be connected in a rotationally fixed manner to the intermediate shaft by means of the second drive switching element. The intermediate shaft can be mechanically operatively connected to the output shaft of the transmission via the second travel spur gear stage by means of the third travel switching element. The intermediate shaft can be mechanically operatively connected to the output shaft of the transmission via the third travel spur gear stage by means of the fourth travel switching element. The result is a compact transmission with simple and inexpensive mechanical components, which can provide three different gear ratios with a fixed gear ratio. The respective torque requirements for the respective electric machines can be very low, which means that they can be very compact radially. In addition, the transmission can provide idle speed. In addition, the third driving switching element and the fourth driving switching element can be switched without load, whereby their wear can be particularly low. In addition, drag losses can be low with this design. Overall, the space requirement is also small, so that the second electric machine can drive the two PTO shafts and further mechanical couplings can be provided. The designation drive switching element is used to assign functions. Driving switching elements can be designed like other switching elements. The intermediate shaft is, for example, arranged coaxially with the input shaft of the transmission.

The drive device can have a first power take-off gear and alternatively or additionally a second power take-off gear. A power take-off gear can be designed to provide a mechanical operative connection between a power take-off shaft and an attachment, for example with different gear ratios. Even if the two PTO shafts are driven together, the first PTO shaft can have a different speed than the second PTO shaft. In addition, it may be possible to operate the second electric machine at a particularly efficient operating point. For example, each power take-off gear can be designed to provide two different gear ratios.

The drive device can be designed to be expanded modularly. In this way, a standardized drive device can be adapted to different customer requirements. Examples of modular extensions can be found in the embodiments described below. The modular expansion of the drive device can take place before installation in the work machine. In another embodiment, the modular expansion can also take place after the drive device has been installed in the work machine.

If two elements are mechanically connected, they are directly or indirectly coupled to one another in such a way that a movement of one element causes a reaction of the other element. For example, a mechanical active connection can be provided by a positive or frictional connection. In the case of a mechanical active connection, one or more spur gear stages can be involved in the drive power transmission. For example, the mechanical active connection can correspond to a meshing of corresponding toothings of two elements. Additional elements, for example one or more spur gear stages, can be provided between the elements.

A permanently rotationally fixed connection between two elements is understood to be a connection in which the two elements are essentially rigidly coupled to one another in all intended states. This also includes a frictional connection, in which intentional or unwanted slippage can occur. Elements that are permanently connected in a rotationally fixed manner can be present as individual components that are connected to one another in a rotationally fixed manner or in one piece.

A connection between two elements via another element can mean that this additional element is involved in an indirect active connection between the two elements. For example, this element can be arranged in the flow of force between these two elements. A connection between two elements via two or more elements can mean that these additional elements are all involved in an indirect active connection between the two elements.

A switchable connection can enable torque transmission between two elements in one state, for example through a rigid coupling, and essentially interrupt this torque transmission in another state. For this purpose, a corresponding switching element can be provided between the two elements.

If a torque can be transferred from one element to another element, actuation of a switching element may be necessary for this, for example in order to establish a mechanical operative connection. However, if a torque can be transferred from one element to another element, this can also be possible in all intended states of the drive device, for example independently of the respective switching states of respective switching elements.

A spur gear stage can, for example, be designed in one or more stages. A single-stage spur gear stage can, for example, have two gears that mesh with one another. A two-stage spur gear stage can, for example, have three gears that mesh with each other in pairs.

A switching element can, for example, be designed to be frictionally or positively locking. An example of a frictional switching element is a multi-plate clutch. An example of a positive switching element is a claw clutch. A switching element can be closed, for example, by actuation. For example, a switching element can be actuated with oil pressure to enable torque transmission between two elements. A switching element can be designed to separate a mechanical operative connection between two elements in one state. A switching element can also be designed as a double switching element, which selectively connects a first element to a second or third element. Optionally, a double switching element can have a neutral position. The drive device can have a control device for controlling the switching elements and thus switching respective operating modes.

In a further embodiment of the drive device, it is provided that the drive device has an intermediate PTO shaft and a first spur gear stage. The intermediate PTO shaft can be mechanically operatively connected to the first PTO shaft by means of a first PTO switching element. For example, the intermediate PTO shaft can be connected in a rotationally fixed manner to the first PTO shaft by means of the first PTO switching element. The intermediate PTO shaft can be mechanically operatively connected to the second PTO shaft by means of a second PTO switching element. For example, the intermediate PTO shaft can be connected in a rotationally fixed manner to the second PTO shaft by means of the second PTO switching element. The second motor shaft can be mechanically operatively connected to the intermediate PTO shaft by means of the first spur gear stage. Only one output shaft and, alternatively or additionally, a power interface are necessary for the second electric machine in order to be able to drive both PTO shafts selectively. A simple and space-saving construction can result. The designation tap switching element is used to assign functions. Tap switching elements can be designed like other switching elements. For example, the two PTO switching elements are designed to be frictionally engaged in order to enable starting and, alternatively or additionally, switching on one of the two PTO shafts when the other PTO shaft is already being driven via the intermediate PTO shaft.

The drive device can have an internal combustion engine with a combustion engine shaft, which is designed to provide combustion engine drive power on the combustion engine shaft. The internal combustion engine can be designed, for example, as a diesel engine. The combustion engine shaft can be mechanically operatively connected to the intermediate PTO shaft, for example by means of a combustion switching element. For example, the combustion engine shaft can be connected in a rotationally fixed manner to the intermediate PTO shaft by means of the combustion switching element. The name combustion switching element is used to assign functions. The combustion engine switching element can be designed like other switching elements. For example, the combustion engine switching element is designed to be frictionally engaged. For example, the first PTO shaft can be mechanically operatively connected to the intermediate PTO shaft via the combustion engine shaft, the combustion engine switching element and the first PTO switching element. For example, the first PTO shaft can be connected in a rotationally fixed manner to the combustion engine shaft by means of the first PTO switching element. The internal combustion engine can drive one or both PTO shafts alone or with the second electric machine. Overall, a particularly high power output can be achieved. However, the internal combustion engine can, for example, not be driven and the first PTO shaft can still be driven by the second electric machine via the internal combustion engine shaft. The internal combustion engine can, for example, also drive the second electric machine in order to generate electricity for an energy storage device or the first electric machine. The second electric machine then acts as a generator. The combustion engine shaft can, for example, extend through the combustion engine, so that it is possible to connect further elements at both axial ends.

In a further embodiment of the drive device, it is provided that the drive device has a second drive output shaft. The second travel output shaft can, for example, be mechanically operatively connected to a front axle of the work machine. The drive device can be designed to transmit drive power from the first motor shaft to the second drive output shaft. The drive device can provide all-wheel drive through the second drive output shaft.

The drive device can be designed for torque transmission from the first drive output shaft to the second drive output shaft. In this way, an unregulated all-wheel drive can easily be provided. In addition, the drive power can be easily transmitted to both drive output shafts via the drive gear. The second travel output shaft can be mechanically operatively connected to the first travel output shaft. However, the second travel output shaft can also be mechanically operatively connected to the first travel output shaft. The drive device can, for example, have an all-wheel spur gear stage and an all-wheel shifting element, wherein the first drive output shaft can be mechanically operatively connected to the second drive output shaft via the all-wheel spur gear stage by means of the all-wheel shift element. The designation four-wheel switching element and four-wheel spur gear stage serves to assign functions. The all-wheel switching element can be designed like other switching elements and the all-wheel spur gear stage can be designed like other spur gear stages. For example, the all-wheel shifting element is designed to be frictionally engaged and the all-wheel spur gear stage is single-stage.

In a further embodiment of the drive device, it is provided that the drive device has an all-wheel spur gear stage, an all-wheel switching element, an additional power switching element and a third electric machine with a third motor shaft, which is designed to provide a third drive power on the third motor shaft. The third motor shaft can be mechanically operatively connected to the second drive output shaft by means of the additional power switching element. The first drive output shaft can be mechanically operatively connected to the second drive output shaft via the all-wheel spur gear stage by means of the all-wheel shifting element. As a result, the third electric machine can support the first electric machine in driving when all-wheel drive is activated. Driving efficiency may be lower when driving with four-wheel drive, so greater power may be required. The third electric machine can then provide this without the first electric machine having to be designed for peak loads that only occur rarely when driving with all-wheel drive. In addition, by dividing the power between the first electric machine and the third electric machine, the available installation space can, for example, be used efficiently and alternatively or additionally very flexibly.

In a further embodiment of the drive device, it is provided that the drive device has a summation gear, a brake and a third electric machine with a third motor shaft, which is designed to provide a third drive power on the third motor shaft. A summation gear can, for example, have a plurality of input shafts and an output shaft on which drive power supplied to the input shafts is provided together. The summing gear can be designed, for example, as a planetary gear set. A brake can be a switching element by means of which a rotatable element can be fixed to a stationary component. The brake can for example, be designed as a frictional switching element. The planetary gear set can have a sun gear, a planet carrier and a ring gear. One or more planet gears can be rotatably mounted on the planet carrier. The planetary gear set is designed, for example, as a minus planetary gear set. In a minus planetary gear set, each planet gear meshes with both the ring gear and the sun gear. A torque can be transferable from the third motor shaft to a first input shaft of the summing gear. The first input shaft of the summing gear can be designed, for example, as a sun gear. The first drive output shaft can be mechanically operatively connected to a second input shaft of the summing gear. Accordingly, the second input shaft of the summation gear can be mechanically operatively connected to the first motor shaft via the drive gear and the first drive output shaft. The second input shaft of the summing gear can be designed, for example, as a ring gear. An output shaft of the summation gear can be permanently connected in a rotationally fixed manner to the second drive output shaft. The output shaft of the summing gear can be designed, for example, as a planet carrier. Using the third electric machine, a translation of the summing gear can be changed. The result is an adjustable all-wheel drive, optionally also in a power-split version. The first input shaft of the summing gear can be locked using the brake. This allows a rigid all-wheel drive to be switched, which can be particularly efficient. When using the rigid all-wheel drive, the third electric machine can be deactivated, for example.

In a further embodiment of the drive device it is provided that the drive device has a motor coupling switching element. The name motor coupling switching element is used to assign functions. Motor coupling switching elements can be designed like other switching elements. For example, respective motor coupling switching elements are designed to be frictionally engaged. The first motor shaft can be mechanically operatively connected to the second motor shaft by means of the motor coupling switching element, for example via a spur gear stage. The active connection can also take place at least partially via a spur gear stage, via which the first motor shaft can be mechanically operatively connected to the first travel output shaft. The motor coupling switching element can, for example, be arranged coaxially on the intermediate PTO shaft, wherein the first motor shaft can be mechanically operatively connected to the intermediate PTO shaft by means of the motor coupling switching element. Through the motor coupling switching element, the first electric machine can support the second electric machine in driving the PTO shafts. Through the motor coupling switching element, the second electric machine can support the first electric machine in driving the travel drive shafts. New operating modes emerge. In addition, respective electric machines can be dimensioned smaller, since usually only low speeds are driven at maximum power take-off load or the machine stands on the spot. Likewise, at maximum driving speed, no or only a small power take-off load is usually required. In addition, a ground speed PTO function can also be provided.

In a further embodiment of the drive device, it is provided that the first motor shaft can be mechanically operatively connected to the second motor shaft by means of the motor coupling switching element via the first travel spur gear stage. For example, an additional spur gear stage can be dispensed with or at least fewer additional gears are required in order to be able to couple the first motor shaft with the second motor shaft. Instead, a mechanical active connection between the first motor shaft and the second motor shaft can also use the first spur gear stage of the transmission. In this case, no actuation of the drive switching elements of the transmission is required to establish the operative connection between the first motor shaft and the second motor shaft, whereby the transmission can continue to be shifted independently. Alternatively or additionally, the drive device can be axially very compact. The motor coupling switching element can, for example, be arranged coaxially with the intermediate PTO shaft. A very compact design can result.

In a further embodiment of the drive device, it is provided that the drive device has a first motor coupling switching element and a second motor coupling switching element. The first motor shaft can be mechanically operatively connected to the second motor shaft by means of the first motor coupling switching element. The first motor shaft can be mechanically operatively connected to the third motor shaft by means of the second motor coupling switching element. The function of the first motor coupling switching element can therefore correspond to the motor coupling switching element described in the previous embodiment. The first motor shaft can also be mechanically operatively connected to the second motor shaft by means of the first motor coupling switching element via the first travel spur gear stage, as already described above in the previous embodiment. Through the two motor coupling switching elements, the first electric machine and the third electric machine can support the second electric machine in driving the PTO shafts. In addition, the third electric machine can also support the first electric machine in driving the travel output shafts. Through the two engines coupling switching elements, the second electric machine can also support the first electric machine in driving the travel drive shafts. This results in new operating modes and a ground speed PTO function.

In a further embodiment of the drive device, it is provided that the drive device has a working hydraulic supply device, a system hydraulic supply device and an auxiliary electric machine with an auxiliary motor shaft. An auxiliary electric machine can be designed as a normal electric machine. The auxiliary electric machine can, for example, be significantly less powerful compared to the first electric machine and the second electric machine and optionally also other electric machines described here. The auxiliary motor shaft can be a normal motor shaft, which was only designated as such for identification purposes. The working hydraulic supply device can be designed to supply working hydraulics with pressure. For example, the work hydraulics can be used to operate the respective tools of the work machine, such as a shovel. A working hydraulic supply device can, for example, have a fixed displacement pump and a variable displacement pump, which are driven together by a shaft. However, a working hydraulic supply device can also have, for example, only one variable displacement pump. The system hydraulic supply device can be designed to supply pressure to respective control hydraulics. For example, the system hydraulic supply device can provide a transmission oil pressure and a pressure for actuating respective switching elements of the drive device. The system hydraulic supply device can, for example, have a constant pump for the transmission oil pressure and a constant pump for the switching element actuation pressure, which are driven together by a shaft. The system hydraulic supply device can also have only one fixed displacement pump. The system hydraulic supply device and the working hydraulic device may be separate devices. Respective oil circuits supplied with this can be fluidically separated at least in a pressure range. The system hydraulic supply device can be mechanically operatively connected to the second motor shaft, for example by means of a spur gear stage via the intermediate PTO shaft.

For example, the auxiliary electric machine is always operated at a predetermined minimum speed when operating the work machine in order to enable the respective switching elements to be actuated. The second electric machine can therefore stand still in certain operating states during operation of the work machine, which can be efficient. In addition, a module consisting of an auxiliary electric machine and a system hydraulic supply device can enable flexible use of installation space independently of other components of the drive device. In addition, the second electric machine can be dimensioned to be less powerful. The auxiliary electric machine and the second electric machine can thus be operated particularly efficiently, for example during normal working cycles of the work machine and less frequently in inefficient operating points. The auxiliary motor shaft can be permanently connected in a rotationally fixed manner to an input shaft of the system hydraulic supply device. A module formed in this way can be free of switching elements and spur gear stages. If, on the other hand, the system hydraulic supply device is driven by the second electric machine, the second electric machine can, for example, always be operated at a predetermined minimum speed when the work machine is being operated in order to enable the respective switching elements to be actuated.

In a further embodiment of the drive device, it is provided that the drive device has a working hydraulic supply device and a system hydraulic supply device. The second motor shaft can be mechanically operatively connected to the working hydraulic supply device and to the system hydraulic supply device. This means there is no need for an auxiliary electric machine. The drive device can, for example, be particularly compact and require few electric machines. In this embodiment, the second electric machine can, for example, always run at a minimum speed when the work machine is operating.

In a further embodiment of the drive device, it is provided that the drive device has a second spur gear stage. The working hydraulic supply device can be permanently connected in a rotationally fixed manner to a shaft of the first spur gear stage. The working hydraulic supply device can be arranged in front of the intermediate PTO shaft in the torque flow from the second drive power. The system hydraulic supply device can be mechanically operatively connected to the second motor shaft via the first spur gear stage and the second spur gear stage. Particularly efficient speed ratios can result, although the second electric machine drives both the system hydraulic supply device and the working hydraulic supply device. The first spur gear stage and the second spur gear stage can have a common gear, which is, for example, permanently connected to the intermediate PTO shaft in a rotationally fixed manner. That's how it can Drive device has particularly few gears.

In a further embodiment of the drive device it is provided that the first driving switching element is designed as a frictional switching element. This means you can easily start driving using the first drive switching element. Alternatively or additionally, the second driving switching element is designed as a frictional switching element. The third driving switching element can be designed as a positive switching element. The fourth driving switching element can be designed as a positive switching element. The second driving switching element can decouple the third and fourth switching elements from the first electric machine in order to enable load-free switching and thus problem-free use of the positive switching elements. Positive switching elements are compact and cost-effective. In addition, positive switching elements are very efficient. This means you can drive with high gear ratios with a high level of efficiency and still switch between second and third gear as needed.

In a further embodiment of the drive device, it is provided that the third drive shift element and the fourth drive shift element are designed together as a double shift element. As a result, the third driving switching element and the fourth driving switching element require little installation space and can also be easily controlled. For example, the third driving shift element and the fourth driving shift element can be designed as a double synchronization. The double switching element can have a neutral position. This allows the second spur gear stage and the third spur gear stage to be decoupled from the output shaft of the transmission at the same time, whereby drag losses can be particularly low in gears without the involvement of these spur gear stages and when idling. Alternatively, the double switching element may not have a neutral position. As a result, the double switching element formed by the third driving switching element and the fourth driving switching element can be particularly simple and compact. Nevertheless, the drive transmission can provide idling by opening the first drive shift element and the second drive shift element. The double switching element, on the other hand, can be free of a switching position which corresponds to a simultaneous closing of the third driving switching element and the fourth driving switching element.

In a further embodiment of the drive device, it is provided that the first drive switching element is arranged coaxially with the second drive output shaft. As a result, drag losses can be low, for example by decoupling the first drive gear stage from the first drive output shaft. Alternatively or additionally, the third travel switching element is arranged coaxially with the second travel output shaft and the fourth travel switching element is arranged coaxially with the second travel output shaft. So drag losses can also be low, for example by decoupling the second driving spur gear stage and the third driving spur gear stage from the first travel output shaft. The second drive switching element can, for example, be arranged coaxially with the input shaft of the drive transmission. This allows the driving gear to be particularly compact.

A second aspect concerns a work machine. The work machine has a drive device according to the first aspect. Respective advantages and further features can be found in the description of the first aspect, with embodiments of the first aspect also forming embodiments of the second aspect and vice versa.

The work machine has a drive axle and, in a further embodiment, an additional drive axle. A torque can be transferable from the first drive output shaft to the first drive axle. A torque can be transferable from the second drive output shaft, if present, to the further drive axle. The drive axle is designed, for example, as the rear axle of the work machine. The further drive axle is designed, for example, as the front axle of the work machine. For example, wheels are arranged at opposite ends on each drive axle. Each drive axle can have an axle differential and, alternatively or additionally, have a wheel drive per wheel. The work machine can have a driving brake, which is arranged, for example, on the rear axle. The work machine can also have a driving brake for each drive axle.

Short description of the characters

• 1 schematically illustrates a first embodiment of a drive device for a work machine with two electric machines.
• 2 schematically illustrates a second embodiment of a drive device for a work machine, which additionally has an internal combustion engine.
• 3 schematically illustrates a third embodiment of a drive device for a work machine, in which the electric machines are connected differently compared to the first embodiment.
• 4 schematically illustrates a fourth embodiment of a drive device for a work machine, in which a work hydraulic supply device and a system hydraulic supply device are connected differently compared to the first embodiment.
• 5 schematically illustrates a fifth embodiment of a drive device for a work machine, in which a first motor shaft and a second motor shaft can be mechanically operatively connected to one another.
• 6 schematically illustrates a sixth embodiment of a drive device for a work machine, which has an auxiliary electric machine by means of which the system hydraulic supply device can be driven.
• 7 schematically illustrates a seventh embodiment of a drive device for a work machine, which has a third electric machine, by means of which a second drive output shaft can also be driven.
• 8th schematically illustrates an eighth embodiment of a drive device for a work machine, in which the motor shafts can be operatively connected differently compared to the seventh embodiment.
• 9 schematically illustrates a ninth embodiment of a drive device for a work machine, which has a third electric machine and a summation gear in order to provide a controllable all-wheel drive in a power-split design.
• 10 schematically illustrates a tenth embodiment of a drive device for a work machine, in which, in comparison to the ninth embodiment, the third motor shaft can be mechanically operatively connected to the first motor shaft.

Detailed Description of Embodiments

1 schematically illustrates a drive device 10 of a work machine. The drive device 10 has a first electric machine EM1 with a first motor shaft 12, which is designed to provide a first drive power to the first motor shaft 12. The drive device 10 has a second electric machine EM2 with a second motor shaft 14, which is designed to provide a second drive power to the second motor shaft 14. In the exemplary embodiment of the first embodiment shown, the two electric machines EM1, EM2 are designed for the same speed and have essentially the same power. The drive device has a first drive output shaft 16 and a second drive output shaft 18. The first drive output shaft 16 is mechanically operatively connected to a rear axle 20. The rear axle 20 has an axle differential 22, a driving brake 24 on both sides, a wheel gear 26 on both sides and a wheel 28 on both sides. The rear axle 20 can be driven via the first drive output shaft 16 for driving the work machine. The second drive output shaft 18 is mechanically operatively connected to a front axle, not shown. The second drive output shaft 18 can be mechanically operatively connected to the first drive output shaft 16 via an all-wheel spur gear stage 30 by means of an all-wheel shifting element AS. A rigid all-wheel drive can be switched on in order to drive the work machine for driving with the rear axle 20 and the front axle together.

The first motor shaft 12 can be mechanically operatively connected to the first drive output shaft 16 by means of a travel gear 32. The transmission 32 has an input shaft 34, an output shaft 36, a first travel gear stage FST1, a second travel spur gear stage FST2, a third travel gear stage FST3, a first travel shift element FS1, a second travel shift element FS2, a third travel shift element FS3, a fourth travel shift element FS4 and an intermediate shaft 38 on. The first driving shift element FS1 and the second driving shift element FS2 are designed to be frictionally engaged. The first drive switching element FS1 is arranged coaxially with the first drive output shaft 16. The second drive switching element FS2 is arranged coaxially with the input shaft 34 of the drive transmission 32. The third driving switching element FS3 and the fourth driving switching element FS4 are designed as a common double switching element in the form of a double synchronization. The double synchronization is arranged coaxially with the output shaft 36 of the transmission 32. The output shaft 36 of the drive transmission 32 is permanently connected in a rotationally fixed manner to the first drive output shaft 16. The input shaft 34 of the drive gear 32 is mechanically operatively connected to the first motor shaft 12, in the case of the first embodiment by a permanently rotationally fixed connection. The input shaft 34 of the drive transmission 32 can be mechanically operatively connected to the output shaft 36 via the first drive gear stage FST1 by means of the first drive switching element FS1. The input shaft 34 of the drive transmission 32 can be connected in a rotationally fixed manner to the intermediate shaft 38 by means of the second drive switching element FS2. The intermediate shaft 38 can be mechanically operatively connected to the output shaft 36 of the travel transmission 32 via the second travel spur gear stage FST2 by means of the third travel switching element FS3. Instead, the intermediate shaft 38 can also be mechanically operatively connected to the output shaft 36 of the travel transmission 32 via the third travel spur gear stage FST3 by means of the fourth travel switching element FS4. So can three translations stages are provided by the transmission 32 with high efficiency. A second and a third gear ratio can be changed load-free on the double switching element by opening the second driving switching element. It is not possible to close the third travel switching element FS3 and the fourth travel switching element FS4 at the same time.

So three gear ratios can be provided by the transmission 32. In the first embodiment of the drive device 10, these three translation stages can be designed very freely.

The drive device has a first PTO shaft 40 and a second PTO shaft 42. The first PTO shaft 40 is designed as a front PTO shaft. The second PTO shaft 42 is designed as a rear PTO shaft. A two-stage power take-off gear 60 is connected to the second PTO shaft 42. A further power take-off gear, not shown, is connected to the first PTO shaft 40. With the two PTO shafts 40, 42, two attachments can be supplied with PTO power. For this purpose, the second motor shaft 14 can be mechanically operatively connected to the first PTO shaft 40 and to the second PTO shaft 42. The second motor shaft 14 is mechanically operatively connected to an intermediate PTO shaft 46 by means of a first spur gear stage 44. The intermediate PTO shaft 46 can be connected in a rotationally fixed manner at the front to the first PTO shaft 40 by means of a first PTO switching element ZF1. The intermediate PTO shaft 46 can be connected in a rotationally fixed manner at the rear to the second PTO shaft 42 by means of a second PTO switching element ZF2.

The drive device 10 has a working hydraulic supply device 48 and a system hydraulic supply device 50. The working hydraulic supply device 48 has a fixed displacement pump 52 and a variable displacement pump 54.

The working hydraulic supply device 48 is designed to supply working hydraulics with pressure in order to be able to hydraulically operate a tool. The system hydraulic supply device 50 has two fixed displacement pumps 56. The system hydraulic supply device 50 is designed to provide a system pressure for actuating the switching elements of the drive device 10 and for actuating a steering system, as well as to provide a transmission oil pressure. The system hydraulic supply device 50 and the working hydraulic supply device 48 are mechanically operatively connected together to the second motor shaft 14 by means of a spur gear stage 58 via the intermediate PTO shaft 46 and the first spur gear stage 44. The second electric machine EM2 always runs at a minimum speed during operation of the work machine in the first embodiment in order to provide a minimum system pressure.

2 shows a second embodiment of the drive device 10, which is similar to the first embodiment. Accordingly, only differences are described.

In the second embodiment of the drive device 10, an internal combustion engine 200 with an internal combustion engine shaft 202, which extends axially through the internal combustion engine 200, is additionally provided. The internal combustion engine shaft 202 can be connected in a rotationally fixed manner to the intermediate PTO shaft 46 by means of a combustion engine switching element VS. The second electric machine EM2 can be driven by the internal combustion engine 200 as a generator. The first PTO shaft 40 can be connected in a rotationally fixed manner to the internal combustion engine shaft 202 by means of the first PTO switching element ZF1. The first PTO shaft 40 can thus be driven by the internal combustion engine 200 or, when the combustion switching element VS is closed, by the second electric machine EM2. The internal combustion engine 200 can be in further embodiments, which are shown in the 3 until 10 are shown, can also be provided.

3 shows a third embodiment of the drive device 10, which is similar to the first embodiment. Accordingly, only differences are described.

In the third embodiment, the first motor shaft 12 is not permanently rotationally fixed to the input shaft 34, but is mechanically operatively connected via a single-stage spur gear stage 500. The first spur gear stage 44, which mechanically connects the second motor shaft 14 to the intermediate PTO shaft 46, is designed in two stages in the third embodiment instead of in one stage, as in the first embodiment.

Due to this additional translation, the two electric machines EM1, EM2 can be designed for a higher speed level in the third embodiment compared to the first embodiment. As a result, the two electric machines EM1, EM2 are radially more compact in the fifth embodiment. In contrast, the two electric machines EM1, EM2 are axially shorter in the first embodiment.

4 shows a fourth embodiment of the drive device 10, which is similar to the third embodiment. Accordingly, only differences are described.

In the fourth embodiment, the working hydraulic supply device 48 is provided with a Shaft 600 of the two-stage first spur gear stage 44 is permanently connected in a rotationally fixed manner. The system hydraulic supply device 50 is mechanically operatively connected to the second motor shaft 14 via the first spur gear stage 44 and a second spur gear stage 602. The first spur gear stage 44 and the second spur gear stage 602 have a common gear 604, which is permanently connected to the intermediate PTO shaft 46 in a rotationally fixed manner. In addition, the spur gear stage 500, which connects the first motor shaft 12 to the input shaft 34 of the drive transmission 32, is designed in multiple stages in the fourth embodiment of the drive device 10.

This results in a stronger radial nesting, so that the fourth embodiment of the drive device 10 is axially very short. This uses a radial installation space that is required by a fuel tank in conventional work machines with internal combustion engines. In addition, better speed levels result on the working hydraulic supply device 48 and the system hydraulic supply device 50. Accordingly, two different gear ratios in the power take-off gear 60 can be dispensed with. In the fourth embodiment, the power take-off gear 60 is therefore designed as a simple spur gear stage without a switching element. In the fourth embodiment, the second electric machine EM2 is designed for higher speeds than the first electric machine EM1.

5 shows a fifth embodiment of the drive device 10, which is similar to the fourth embodiment. Accordingly, only differences are described.

In the fifth embodiment of the drive device 10, a first motor coupling switching element MS1 is additionally provided. The first motor shaft 12 can be mechanically operatively connected to the second motor shaft 14 by means of the first motor coupling switching element MS1. In the embodiment shown, the first driving spur gear stage FST1 can be mechanically operatively connected to the intermediate PTO shaft 46 via the first motor coupling switching element MS1. For this purpose, a gear 702 is mounted on the intermediate PTO shaft 46, which meshes with a gear of the first driving spur gear stage FST1. This makes it possible to dispense with an additional complete and separate spur gear stage for the effective connection of the first motor shaft 12 to the second motor shaft 14. The first motor coupling switching element MS1 is arranged on the intermediate PTO shaft 46 and is designed to connect the gear 702 to the intermediate PTO shaft 46 in a switchable, rotationally fixed manner.

Accordingly, the first electric machine 12 and the second electric machine 14 can support each other in driving the two PTO shafts 40, 42 and the two travel output shafts 16, 18. The overall system performance can be lower because the working machine usually does not have to provide maximum power take-off and maximum driving performance at the same time. In the example shown, the second electric machine EM2 is therefore designed for a lower maximum power than the first electric machine EM1. Accordingly, the second electric machine EM2 is particularly small in the fifth embodiment. In addition, a ground speed PTO function is provided.

6 shows a sixth embodiment of the drive device 10, which is similar to the fifth embodiment. Accordingly, only differences are described.

In the sixth embodiment of the drive device 10, the system hydraulic supply device 50 is not driven by the second electric machine EM2. Accordingly, the second spur gear stage 602 is also omitted. Instead, the sixth embodiment of the drive device 10 has an auxiliary electric machine HM with an auxiliary motor shaft 900. The auxiliary motor shaft 900 is mechanically operatively connected to the system hydraulic supply device 50, in the example shown by the auxiliary motor shaft 900 being permanently non-rotatably connected to the drive shaft of the system hydraulic supply device 50. This allows the system hydraulic supply device 50 to be arranged and driven independently. This improves flexibility in the use of installation space. In addition, the second electric machine EM2 can be switched off when no power take-off or support of the traction drive is required from the second electric machine EM2. The auxiliary electric machine HM is operated at a minimum speed instead of the second electric machine EM2 when the work machine is operating. This means that the second electric machine EM2 can be operated more frequently at an efficient operating point. A maximum power of the auxiliary electric machine HM is significantly lower than that of the two electric machines EM1, EM2.

7 shows a seventh embodiment of the drive device 10, which is similar to the fifth embodiment. Accordingly, only differences are described.

The seventh embodiment of the drive device 10 additionally has a third electric machine EM3 with a third motor shaft 1000. The third electric machine EM3 is designed to provide a third drive power on the third motor shaft. The third motor shaft 1000 has a multi-stage spur gear stage 1002 can be mechanically operatively connected to the second drive output shaft 18 by means of an additional power switching element ZL. The third electric machine EM3 is designed for a lower power than the first electric machine EM1.

In the seventh embodiment of the drive device 10, a controllable all-wheel drive function can be provided in addition to a rigid all-wheel drive function. When the all-wheel drive switching element AS is activated, the two drive axles are driven at a fixed speed ratio. By actuating the additional power switching element ZL and with the all-wheel switching element AS closed, the third electric machine EM3 can support the first electric machine EM1 in driving both the two PTO shafts 40, 42 and the two drive output shafts 16, 18. Accordingly, the first electric machine in this embodiment can be designed for a lower power, whereby installation space and costs can be saved. When the all-wheel drive switching element AS is not actuated but the additional power switching element ZL is activated, the third electric machine EM3 can drive the second drive output shaft 18 independently of the first drive output shaft 16. A speed ratio from the second drive output shaft 18 to the first drive output shaft 16 can be varied for an adjustable all-wheel drive.

8th shows an eighth embodiment of the drive device 10, which is similar to the seventh embodiment. Accordingly, only differences are described.

In the eighth embodiment, the third motor shaft 1000 can be mechanically operatively connected to the second motor shaft 14 by means of a second motor coupling switching element MS2. For this purpose, a spur gear stage 1100 is provided, which uses a gear of the spur gear stage 1002 that is permanently connected to the third motor shaft 1000 in a rotationally fixed manner. In the eighth embodiment, the first motor shaft 12 can also continue to be mechanically operatively connected to the second motor shaft 14. If the first motor coupling switching element MS1 and the second motor coupling switching element MS2 are actuated, the drive power can be transmitted from the first electric machine EM1 and the second electric machine EM3 to the intermediate PTO shaft 46.

In the eighth embodiment, the first electric machine EM1 and the third electric machine EM3 are designed so that a maximum required driving power can only be provided together. As a result, the drive device 10 of the eighth embodiment is compact and inexpensive.

9 shows a ninth embodiment of the drive device 10, which is similar to the seventh embodiment. Accordingly, only differences are described.

In the ninth embodiment, the first electric machine EM1 and the third electric machine EM3 are connected in such a way that the drive device 10 is electrically power-split and can provide a variable all-wheel drive. The additional power switching element ZL is no longer required. In addition, a summation gear 1200 is provided, which is designed as a minus planetary gear set with a sun gear 1202 as the first input shaft, a ring gear 1204 as the second input shaft and a planet carrier 1206 as the output shaft. Several planet gears 1208 are rotatably mounted on the planet carrier, each of which meshes with the sun gear 1202 and the ring gear 1204.

The third motor shaft 1000 is mechanically operatively connected to the sun gear 1202 via the spur gear stage 1002. The first drive output shaft 16 is mechanically operatively connected to the ring gear 1204 via the all-wheel spur gear stage 30, so that a torque can be transmitted from the first motor shaft 12 to the second input shaft of the summing gear 1200 via the drive gear 32. The planet carrier 1206 is permanently connected to the second drive output shaft 18 in a rotationally fixed manner. With the third electric machine EM3, a transmission ratio on the summing gear 1204 can be varied. The third electric machine EM3 is designed for low loads, as it essentially only varies the gear ratio.

The sun gear 1202 of the summing gear 1200 can be fixed using an additional brake 1210. This allows a rigid all-wheel drive to be provided, which allows efficient driving without support from the third electric machine EM3.

10 shows a tenth embodiment of the drive device 10, which is essentially a combination of the eighth embodiment with the ninth embodiment. Accordingly, only differences are described.

In the tenth embodiment, the first motor coupling switching element MS1 and the second motor coupling switching element MS2 are also provided, as in the eighth embodiment. The third motor shaft 1000 can thus be mechanically operatively connected to the first motor shaft 12 by means of the second motor coupling switching element MS2. The first motor shaft 12 can thus be mechanically operatively connected to the second motor shaft 14 by means of the first motor coupling switching element MS1.

In addition, in the tenth embodiment, the summing gear 1200 is provided, as in the ninth embodiment. The third motor shaft 1000 is mechanically operatively connected to the sun gear 1202 via the spur gear stage 1002. As in the ninth embodiment, the first drive output shaft 16 is mechanically operatively connected to the ring gear 1204 via the all-wheel spur gear stage 30, so that a torque can be transmitted from the first motor shaft 12 to the second input shaft of the summing gear 1200 via the drive gear 32. The planet carrier 1206 is permanently connected to the second drive output shaft 18 in a rotationally fixed manner.

Reference symbols

10

Drive device

12, 14, 1000

Motor shafts

16, 18

Travel output shafts

20

rear axle

22

Axle differential

24

Driving brake

26

Wheel gear

28

wheel

30

All-wheel spur gear stage

32

Travel gear

34

input shaft

36

output shaft

38

Intermediate shaft

40, 42

PTO shafts

44, 58, 500, 602, 1002, 1100

Spur gear stage

46

PTO intermediate shaft

48

Working hydraulic supply device

50

System hydraulic supply device

52, 56

Constant pump

54

Variable displacement pump

60

PTO gearbox

200

Internal combustion engine

202

Combustion engine shaft

600

Wave

604

gear

702

gear

900

Auxiliary motor shaft

1200

summing gear

1202

sun gear

1204

ring gear

1206

Planet carrier

1208

Planetary gears

1210

brake

EM1-EM3

Electric machines

HM

Auxiliary electric machine

AS

All-wheel drive shift element

FST1-FST3

Driving spur gear stages

FS1-FS4

Driving switching elements

ZF1, ZF2

Tap switching elements

VS

Combustion switching element

MS1, MS2

Motor coupling switching elements

ZL

Additional power switching element

Claims (15)

Drive device (10) for a work machine, wherein the drive device (10) has a first electric machine (EM1) with a first motor shaft (12), which is designed to provide a first drive power to the first motor shaft (12), a second electric machine (EM2 ) with a second motor shaft (14), which is designed to provide a second drive power to the second motor shaft (14), a first drive output shaft (16), a first PTO shaft (40) and a second PTO shaft (42), the first motor shaft (12) can be mechanically operatively connected to the first drive output shaft (16) by means of a travel gear (32), and wherein the second motor shaft (14) can be mechanically operatively connected to the first PTO shaft (40) and to the second PTO shaft (42), wherein the travel gear (32) has an input shaft (34), an output shaft (36), a first travel spur gear stage (FST1), a second travel spur gear stage (FST2), a third travel spur gear stage (FST3), a first travel shift element (FS1), a second travel shift element (FS2 ), a third driving switching element (FS3), a fourth driving switching element (FS4) and an intermediate shaft (38), the output shaft (36) of the driving gear (32) being permanently connected in a rotationally fixed manner to the first driving output shaft (16), the input shaft ( 34) of the travel gear (32) is mechanically operatively connected to the first motor shaft (12), the input shaft (34) of the travel gear (32) being mechanically connected to the output shaft (36) via the first drive gear stage (FST1) by means of the first drive switching element (FS1). can be operatively connected, the input shaft (34) of the drive gear (32) being activated by means of the second travel switching element (FS2) can be connected in a rotationally fixed manner to the intermediate shaft (38), the intermediate shaft (38) being mechanically operatively connected to the output shaft (36) of the travel transmission (32) via the second travel gear stage (FST2) by means of the third travel switching element (FS3) and wherein the intermediate shaft (38) can be mechanically operatively connected to the output shaft (36) of the travel transmission (32) via the third travel spur gear stage (FST3) by means of the fourth travel switching element (FS4). Drive device (10). Claim 1 , characterized in that the drive device (10) has an intermediate power take-off shaft (46) and a first spur gear stage (44), the second motor shaft (14) being mechanically operatively connected to the intermediate power take-off shaft (46) by means of the first spur gear stage (44), the The intermediate PTO shaft (46) can be mechanically operatively connected to the first PTO shaft (40) by means of a first PTO switching element (ZF1) and the intermediate PTO shaft (46) can be mechanically operatively connected to the second PTO shaft (42) by means of a second PTO switching element (ZF2). Drive device (10). Claim 1 or 2 , characterized in that the drive device (10) has a second travel output shaft (18), a torque being transferable from the first travel output shaft (16) to the second travel output shaft (18). Drive device (10). Claim 3 , characterized in that the drive device (10) has an all-wheel spur gear stage (30), an all-wheel switching element (AS), an additional power switching element (ZL) and a third electric machine (EM3) with a third motor shaft (1000), which is designed to provide a third drive power on the third motor shaft (1000), wherein the third motor shaft (1000) can be mechanically operatively connected to the second travel output shaft (18) by means of the additional power switching element (ZL) and wherein the first travel output shaft (16) is connected to the second travel output shaft (18). the all-wheel spur gear stage (30) can be mechanically operatively connected by means of the all-wheel switching element (AS). Drive device (10). Claim 3 , characterized in that the drive device (10) has a summing gear (1200), a brake (1210) and a third electric machine (EM3) with a third motor shaft (1000), which is designed to provide a third drive power to the third motor shaft (1000 ). is, wherein an output shaft (1206) of the summation gear (1200) is permanently connected in a rotationally fixed manner to the second travel output shaft (18) and wherein the first input shaft (1202) of the summation gear (1200) can be fixed by means of the brake (1210). Drive device (10) according to one of the preceding claims, characterized in that the drive device (10) has a motor coupling switching element (MS1), wherein the first motor shaft (12) can be mechanically operatively connected to the second motor shaft (14) by means of the motor coupling switching element (MS1). Drive device (10). Claim 6 , characterized in that the first motor shaft (12) can be mechanically operatively connected to the second motor shaft (14) by means of the motor coupling switching element (MS1) via the first travel spur gear stage (FST1). Drive device (10). Claim 4 or 5 , characterized in that the drive device (10) has a first motor coupling switching element (MS1) and a second motor coupling switching element (MS2), wherein the first motor shaft (12) can be mechanically operatively connected to the second motor shaft (14) by means of the first motor coupling switching element (MS1) and wherein the first motor shaft (12) can be mechanically operatively connected to the third motor shaft (1000) by means of the second motor coupling switching element (MS2). Drive device (10) according to one of the preceding claims, characterized in that the drive device (10) has a working hydraulic supply device (48), a system hydraulic supply device (50) and an auxiliary electric machine (HM) with an auxiliary motor shaft (900), the second motor shaft (14 ) is mechanically operatively connected to the working hydraulic supply device (48) and wherein the auxiliary motor shaft (900) is mechanically operatively connected to the system hydraulic supply device (50). Drive device (10) according to one of the preceding Claims 1 until 8th , characterized in that the drive device (10) has a working hydraulic supply device (48) and a system hydraulic supply device (50), the second motor shaft (14) being mechanically operatively connected to the working hydraulic supply device (48) and to the system hydraulic supply device (50). Drive device (10). Claim 10 , characterized in that the drive device (10) has a second spur gear stage (602), the working hydraulic supply being provided Direction (48) is permanently connected in a rotationally fixed manner to a shaft (600) of the first spur gear stage (44) and the system hydraulic supply device (50) is mechanically operatively connected to the second motor shaft (14) via the first spur gear stage (44) and the second spur gear stage (602). is, wherein the first spur gear stage (44) and the second spur gear stage (602) have a common gear (604). Drive device (10) according to one of the preceding claims, characterized in that the first driving switching element (FS1) is designed as a friction-locking switching element, the second driving switching element (FS2) is designed as a friction-locking switching element, the third driving switching element (FS3) is designed as a positive switching element and the fourth driving switching element (FS4) is designed as a positive switching element. Drive device (10) according to one of the preceding claims, characterized in that the third driving switching element (FS3) and the fourth driving switching element (FS4) are designed together as a double switching element. Drive device (10). Claim 12 , characterized in that the first travel switching element (FS1) is arranged coaxially with the second travel output shaft (18), the third travel switching element (FS3) is arranged coaxially with the second travel output shaft (18) and the fourth travel switching element (FS4) is coaxial with the second travel output shaft (18) is arranged. Work machine with a drive axle and a drive device (10) according to one of the preceding claims, wherein a torque can be transmitted from the first drive output shaft (16) to the drive axle.

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