Method for operating a drive train, drive train, and work machine

Abstract

The invention relates to a method for operating a drive train of a work machine. The drive train comprises at least one first electric machine (60) having a first motor shaft (62) for driving a first axle arrangement (12), and at least one first power take-off electric machine (92) having a first power take-off motor shaft (94) for driving a first power take-off shaft (96) of a first power take-off drive. The power take-off drive and the first axle arrangement (12) are decoupled in at least one state of the drive train. The method comprises a step of setting (600) a travelling speed of the work machine. The method also comprises a step of setting (602) a rotational speed of the first power take-off shaft (96) independently of the set travelling speed. The invention also relates to a drive train and to a work machine.

Description

[0001] ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0002] Method for operating a drive train, drive train and working machine

[0003] The present invention relates to a method for operating a drive train of a working machine. Furthermore, the invention relates to a drive train and a working machine.

[0004] State of the art

[0005] A machine's drivetrain can provide both driving power at an output shaft and working power, for example, at a power take-off (PTO) shaft. Electrification can often significantly reduce the complexity of the drivetrain. Furthermore, it can considerably lower the environmental impact of operating the machine. Therefore, many conventionally powered machines are being retrofitted with an electrified drivetrain. However, the energy storage system required to operate an electrified drivetrain is typically much larger than the fuel tank of a conventionally powered machine. This can make integrating an electrified drivetrain challenging.

[0006] Description of the invention

[0007] A first aspect concerns a method for operating the drivetrain of a machine. The drivetrain can, for example, be designed to provide propulsion power for driving the machine. Alternatively or additionally, the drivetrain can optionally also provide work power, for example, for moving or otherwise operating the machine's tools. The work power can, for example, be provided mechanically at one or more power take-off shafts. The work power can also be provided hydraulically. The propulsion power can, for example, be provided at one or more driven axles. The machine can be, for example, an agricultural machine or a construction machine (ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06). An example of an agricultural machine is a tractor.An example of a construction machine is a wheel loader.

[0008] The drive train comprises at least one first electric motor with a first motor shaft for driving a first axle assembly. The drive train may include the first axle assembly. An axle assembly may include a drive motor and an output shaft, thereby driving the machine.

[0009] The drive train comprises a first power take-off unit with a first power take-off motor shaft for driving a first power take-off shaft of a first power take-off unit. The drive train can include the first power take-off unit. A power take-off unit can have a drive motor and a power take-off shaft, enabling the operation of an implement. The drive motor of the power take-off unit can be the first power take-off unit. The drive train can thus provide drive power to the implement.

[0010] The drivetrain, for example its first axle assembly, includes the first electric motor with the first motor shaft. The first axle assembly can also include a first differential, a first output shaft, a second output shaft, a first output element, and a second output element. An electric motor can be, for example, a synchronous motor or an asynchronous motor. The electric motor can, for example, convert electrical energy into mechanical energy. The electric motor can, for example, have only one motor shaft, which is set in rotation during operation. The electric motor can also be designed for recuperation. A differential can be designed to translate an input signal into an output signal. For example, the differential can translate speed into speed.The differential gear can optionally be configured to provide different gear ratios. The differential gear can be configured to provide a differential function. The differential gear can have one input shaft and two output shafts. The output shafts can rotate at different speeds, for example, depending on the torque applied to the output shafts. The differential gear can transmit engine power from the first engine shaft to the two output shafts. The first and second output shafts can each, for example, form an output shaft or be rotationally fixed to it. An output element can be a component by means of which the drive train can transmit drive power to a surface on which the machine is standing.For example, the output elements can be designed as wheels or as pinions to drive a track. The first and second output elements can be arranged on opposite sides of the machine. For example, the first output element can be a left wheel and the second output element a right wheel of a driven axle of the machine.

[0011] The first power take-off (PTO) drive can include the first PTO electric motor with the first PTO motor shaft and the first power take-off (PTO) shaft. The designation "PTO electric motor" can serve for identification purposes. The PTO electric motor can be designed like other electric motors. The PTO electric motor can be designed for lower power output than the first electric motor. The designation "PTO motor shaft" can also serve for identification purposes. The PTO motor shaft can be a motor shaft of a PTO electric motor. The PTO shaft can be a shaft at which power can be supplied externally by the machine. For example, the PTO shaft can protrude from the front or rear of the machine. The PTO shaft can be designed for connecting and driving an implement. The first PTO shaft can, for example, be located adjacent to the first axle assembly, in particular its first output shaft and its second output shaft.For example, the first axle assembly, with its first and second output shafts, can form a driven rear or front axle of the machine. Similarly, the first power take-off (PTO) shaft can form a rear or front PTO shaft of the machine. The first PTO electric motor can be located, for example, in front of or behind the first axle assembly in the longitudinal direction of the vehicle. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06.

[0012] In machinery with internal combustion engines, the power take-off (PTO) shaft and axle assembly are typically driven jointly by the engine. In operation, the PTO speed is then dependent on the vehicle speed and can only be changed in discrete steps by shifting gears in a PTO gearbox. This means that the work result is not always optimal, and in many situations, the full power of the drivetrain cannot be utilized.

[0013] In this embodiment, the PTO drive and the first axle assembly are decoupled in at least one state of the drivetrain. For example, the first axle assembly and the PTO shaft are free of any mechanical connection. In another embodiment, a mechanical connection can be disconnected by a switching element, such as a multi-plate clutch or dog clutch. Furthermore, the PTO drive and a drive system each have an associated electric motor: the PTO electric motor and the first electric motor. This allows the driving speed and the PTO shaft speed to be set independently of each other. This means, for example, that full PTO power can be accessed regardless of the driving speed. Depending on the work objective, power reserves can thus be used for faster operation and, alternatively or additionally, for improved work results.For example, depending on the nature of a field, the driving speed and the rotational speed of the PTO shaft can be adjusted independently of each other during processing for particularly efficient work and a particularly good work result.

[0014] The process includes a step for setting the travel speed of the working machine. For this purpose, the rotational speed of the first electric motor and, optionally, of other electric motors driving the working machine can be set. Alternatively or additionally, a gear ratio in the drive train between the respective electric motors and axle arrangements, such as between the first electric motor and the first axle arrangement, can be set. For this purpose, a gearbox with an adjustable gear ratio can be used, for example. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0015] The procedure also includes a step for setting the rotational speed of the first power take-off (PTO) shaft, for example, within a specified range. The rotational speed of the first PTO shaft can be a specific rotational speed of the first PTO shaft. Setting the rotational speed of the first PTO shaft can be achieved by adjusting the rotational speed of the first PTO motor. Alternatively or additionally, a gear ratio in the drive train between the respective PTO motors and the PTO shafts, such as between the first PTO motor and the first PTO shaft, can be adjusted. For this purpose, a gearbox with an adjustable gear ratio can be used, for example.

[0016] The rotational speed of the first PTO shaft is set independently of the set ground speed. Likewise, the ground speed can be set independently of the rotational speed of the first PTO shaft and can optionally be varied. The adjustment range can have a lower and, alternatively, an upper limit. The limits of the adjustment range can be fixed or variable. This allows the ground speed and the PTO speed to be optimized and coordinated according to power reserves and work results, instead of having a fixed relationship that, for example, cannot be modified at all or only incrementally via a gearshift. The relationship between ground speed and the rotational speed of the first PTO shaft can thus be set with a high degree of variability.

[0017] If driving power is provided by multiple electric motors, these electric motors can be controlled jointly to determine the driving speed. If working power at a power take-off (PTO) shaft is provided by multiple PTO electric motors, these PTO electric motors can be controlled jointly to determine the rotational speed. If multiple PTO shafts are provided, their respective rotational speeds can be set independently of each other and, alternatively or additionally, independently of the driving speed, for example, within a set range. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0018] Each power take-off (PTO) shaft can have an assigned adjustment range, or a single adjustment range can apply to all PTO shafts. Specifications relating to only one electric motor as a traction motor, or only to one PTO electric motor and one PTO shaft, can apply equally to several of these components, provided they are designed and applicable.

[0019] In one embodiment of the method, the method may include a step for detecting a vehicle state. This can be accomplished by a detection device, which may be part of the drivetrain or the working machine. The detection device may include appropriate sensors, such as a speed sensor, accelerometer, GPS receiver, camera, tachometer, or the like. The vehicle state may, for example, be its position on a map, its driving speed, the charge level of an energy storage device, the type of terrain, and alternatively or additionally, data on an attachment and the results of work performed by the working machine. The method may also include a step for specifying a setpoint range for the rotational speed of the first power take-off shaft, depending on the detected vehicle state.This allows the adjustable rotational speed of the first power take-off shaft to be limited, taking the vehicle's condition into account. This prevents, for example, a setting that is incompatible with the current vehicle condition, such as the current driving speed.

[0020] In one embodiment of the method, the rotational speed of the first power take-off shaft can be adjusted automatically. For example, the rotational speed can be automatically adjusted depending on the detected vehicle status, a request from an implement, a position on a map, and alternatively or additionally, a work result. This can be achieved, for example, by means of an analytical evaluation or a machine learning model, which is, for instance, a previously trained neural network. An adjustment device can be provided for this purpose. The driving speed can also be adjusted automatically (ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06). The type of automatic adjustment can be modifiable by a user. The automatic adjustment relieves the driver of manual tasks.Alternatively or additionally, the respective settings can also be made manually by the user.

[0021] In one embodiment of the method, the rotational speed of the first power take-off (PTO) shaft can be adjusted manually, for example, by a driver. The possible settings may be limited by the adjustment range. For manual adjustment, a control element such as a lever, touchscreen, or pedal may be provided. The driver can set the rotational speed as an absolute value or as a ratio to the ground speed. Adjustment can be free, at least within the adjustment range, and can also be performed continuously, either as an alternative or additional step. This allows the driver to precisely control the work result and ensure efficient utilization of the available system power of the machine. The ground speed can also be manually adjustable in this way.

[0022] In one embodiment of the method, the rotational speed of the first power take-off (PTO) shaft can be set as a ratio to the ground speed of the machine. The ground speed can be known indirectly via the rotational speed of the electric motor and a tire size, or it can be detected, for example, by a GPS receiver or speed sensor. Alternatively, the set ground speed can simply be used, although this may differ from the actual ground speed due to variations in tire circumference and slippage. No sensors are required for this. The ratio can be set manually or automatically. This ratio can provide a ground-speed PTO function.Unlike, for example, a machine with an internal combustion engine, the ratio cannot be freely selected in discrete steps or using highly complex continuously variable transmissions. Instead, the ratio can be easily set electronically. When using a terrestrial positioning system such as GPS (ZF Friedrichshafen AG File 303681, Friedrichshafen, 2024-08-06), slippage during driving can also be compensated for, unlike with a mechanically provided power take-off (PTO) function.

[0023] In one embodiment of the method, the first PTO drive and the first axle assembly can be permanently decoupled. This means, for example, that a functional connection cannot be established by closing a corresponding switching element. This avoids any undesirable interaction with the independent adjustability of the driving speed and rotational speed of the respective PTO shafts.

[0024] In one embodiment of the method, the method may include a step of adjusting the drive train to a state in which the first power take-off (PTO) drive and the first axle assembly are decoupled. This interrupts a mechanical connection. For example, a corresponding switching element is actuated for this purpose. This step can, for example, be performed before setting the rotational speed of the respective PTO shafts to avoid any effect on the driving speed.

[0025] A second aspect concerns a drive train for a machine. The drive train can be configured to operate using a method according to the first aspect. The respective advantages and further features are described in the first aspect, whereby embodiments of the first aspect also constitute embodiments of the second aspect and vice versa. The drive train can be configured to provide a motive force and a working force. The drive train can include at least one first electric motor with a first motor shaft for driving a first axle assembly and at least one first power take-off electric motor with a first power take-off motor shaft for driving a first power take-off shaft of a first power take-off drive. The power take-off drive and the first axle assembly are decoupled in at least one state of the drive train.The drive train has a first control device designed for setting the travel speed of the machine. The drive train has a second control device designed for a set speed of the machine. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06.

[0026] The system allows for independent adjustment of the rotational speed of the first power take-off shaft, for example, within a specified range. The first and second control devices can be combined into a single control device. This control device can, for example, include an inverter, a microprocessor, or a computer.

[0027] The drivetrain can include the first axle assembly and the first power take-off (PTO) drive. The first axle assembly can include the first electric motor with the first motor shaft, a first differential, a first output shaft, a second output shaft, a first output element, and a second output element. The first PTO drive can include the first PTO electric motor with the first PTO motor shaft and the first power take-off shaft.

[0028] The first motor shaft can be mechanically connected to the first and second output shafts via the differential. This allows drive power from the first motor shaft to be distributed between the two output shafts via the differential. The first motor shaft can be arranged coaxially with the first output shaft and, alternatively or additionally, with the second output shaft. The first and second output shafts can also be arranged coaxially with each other. The two output shafts can, for example, extend transversely across the vehicle. In this way, the first electric motor can form a coaxial axle drive, making the drive arrangement particularly compact and easy to integrate into the vehicle. The first output shaft can be mechanically connected to the first output element.This allows for a compact transfer of drive power to the ground and optionally provides a further gear ratio in the connection between the first output shaft and the first output element. The first output shaft and the first output element can be arranged coaxially. The second output shaft can be mechanically connected to the second output element. This allows for a compact transfer of drive power to the ground and optionally provides a further gear ratio in the connection between the second output shaft and the second output element. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06.

[0029] Output element must be available. The second output shaft and the second

[0030] Output elements can be arranged coaxially to each other.

[0031] The first differential gear can include a first differential lock, a first planetary gear set with a first sun gear, a first planet carrier, and a first ring gear, and a second planetary gear set with a second sun gear, a second planet carrier, and a second ring gear. The planetary gear set can be designed compactly with few components to provide both a transmission from the first electric motor to the output of the driven machine and to perform the differential function. The first differential lock can be configured to connect the two output shafts of the differential gear in a rotationally fixed manner. This allows for the integration of the differential lock with minimal effort. The first differential lock can, for example, be designed as a switching element by means of which the first and second output elements can be connected in a rotationally fixed manner. The first ring gear is permanently and rotationally fixed to the second sun gear.The two planetary gear sets can be stacked radially. The second planetary gear set can, for example, extend in the same axial range as the first planetary gear set. For instance, all rotating elements of the second planetary gear set can be arranged radially outside the first planetary gear set. This results in a very compact axial design, allowing the differential and the first electric motor to be arranged coaxially side-by-side in the longitudinal direction of the vehicle within the driven machine. The first ring gear and the second sun gear can, for example, be formed as a single piece. An internal toothing can form the first ring gear section, and an external toothing the second sun gear section. Each planetary gear set can, for example, have only one sun gear, one planet carrier, and one ring gear. For instance, the second planetary gear set can have only a single sun gear.For example, the first motor shaft is permanently and rotationally fixed to the input shaft of the differential gear.

[0032] The numbering of rotating elements can serve to assign them to a planetary gear set. For example, the designation as the second sun gear (ZF Friedrichshafen AG file 303681, Friedrichshafen, August 6, 2024) can serve to clearly assign this sun gear to the second planetary gear set. Generally, the numbering, and alternatively or additionally the designation of components according to their assembly group, can serve this purpose.

[0033] The first PTO motor shaft can be mechanically connected to the first power take-off (PTO) shaft. For example, the first PTO motor shaft can be mechanically connected to the first PTO shaft via a spur gear stage and, alternatively or additionally, a bevel gear stage. The first PTO motor shaft can be connected to the first PTO shaft, for example, via a first PTO switching element. The first PTO switching element can be located, for example, in the longitudinal direction of the vehicle in front of or behind the first axle assembly. The first PTO switching element can be located, for example, in the longitudinal direction of the vehicle relative to the first axle assembly, and alternatively or additionally, the first motor shaft can be located on the side of the PTO motor or on the side of the PTO shaft. The first PTO switching element can be designed as a conventional switching element, for example, as a friction-fit or positive-locking coupling.The first PTO engine shaft and the first power take-off (PTO) shaft can be connected via a first PTO gearbox. The PTO gearbox can, for example, be designed to provide two gears for this connection. A connection between the first PTO engine shaft and the first PTO shaft can be referred to as the first PTO functional connection. For example, the first PTO functional connection can include shafts for torque transmission. The first PTO functional connection can be designed to transmit torque from the first PTO engine shaft to the first PTO shaft. The PTO engine shaft can, for example, extend transversely (e.g., orthogonally) or parallel to the first output shaft, the second output shaft, and alternatively or additionally to the first engine shaft.

[0034] The first power take-off (PTO) connection from the first PTO motor shaft to the first PTO shaft can extend transversely to the first output shaft and, alternatively or additionally, transversely to the second output shaft between the first electric motor and the differential gear in an axial direction of the first output shaft. This arrangement allows the differential gear and the first electric motor to be well integrated into the machine (ZF Friedrichshafen AG File 303681, Friedrichshafen, August 6, 2024) and the first PTO shaft to be located at an easily accessible point within the machine. For example, at least one connecting shaft of the first PTO connection extends orthogonally to the first output shaft and, alternatively or additionally, to the first motor shaft. This connecting shaft can, for example, extend in the longitudinal direction of the machine.The connecting shaft can, for example, extend centrally within the machine in the transverse direction of the vehicle, which may correspond to the axial direction of the first output shaft. For instance, the first differential gear can be located to the left of the connecting shaft and the first electric motor to the right. The first pivot connection, for example, intersects the first output shaft, the second output shaft, and, alternatively or additionally, a connection from the first motor shaft to the first differential gear in a top view of the machine. For example, the first pivot connection may be routed below the output shaft, passing alongside it. Due to the typically large diameters of output elements in machine tools, sufficient installation space and ground clearance can be ensured, resulting in a compact design.The axial extent of the first electric motor can be defined by its rotor and, alternatively or additionally, its stator. The first rotor and, alternatively or additionally, the first stator can be arranged transversely to the vehicle or along an axial extent of the output shaft on one side of the first power take-off connection, and the differential gear can be arranged on the opposite side of the power take-off connection, transversely to the vehicle or along an axial extent of the two output shafts. The first differential lock can, for example, be arranged on the side of the differential gear facing away from the first electric motor.

[0035] The second PTO motor shaft can be mechanically connected to a pump device. This pump device can, for example, supply pressure to the hydraulic system of the machine. The PTO motor can also drive the pump device, thus enabling the hydraulic system to be pressurized. The drive train can also include additional electric motors for driving further pump devices (ZF Friedrichshafen AG File 303681, Friedrichshafen, August 6, 2024). These additional pump devices can, for example, supply pressure to a steering system, hydraulic switching elements, and, alternatively or additionally, to transmission lubrication. The hydraulic system can also be supplied with pressure by a separate electric motor.

[0036] The first output shaft can be operatively connected to the first output element, for example, via a planetary gear set or a spur gear stage. This allows for a further gear ratio to be provided there. Similarly, the second output shaft can be operatively connected to the second output element via a planetary gear set or a spur gear stage. For example, such a planetary gear set can be arranged within the associated output element.

[0037] A rotationally fixed connection between two elements is understood to be a connection in which the two elements are essentially rigidly coupled to each other in all intended states. This also includes a friction-fit connection, in which intentional or unintentional slippage can occur. Permanently rotationally fixed elements can, for example, exist as permanently rotationally fixed individual components or as a single piece.

[0038] A connection of two elements via another element can mean that this additional element can participate in an indirect functional connection between the two elements. For example, this element can be located in the force flow between these two elements. A connection of two elements via two or more elements can mean that these additional elements are all involved in an indirect functional connection between the two elements. A switchable connection can, in one state, enable torque transmission between two elements, for example, through a rigid coupling, and, in another state, essentially interrupt this torque transmission. A corresponding switching element can be provided between the two elements for this purpose. If two elements can be connected in a rotationally fixed manner, these two elements can, for example, be connected to each other in a rotationally fixed manner via a switching element. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06.If two elements can be mechanically connected, these two elements can, for example, be connected via a switching element for torque transmission.

[0039] A planetary gear set is configured, for example, as a negative planetary gear set or a positive planetary gear set. The sun gears, planet carriers, and ring gears of a planetary gear set constitute its rotating elements. Each planetary gear set can have one or more planet gears, which are rotatably mounted on the planet carrier. For example, the planet gears of a planetary gear set mesh with a sun gear and a ring gear of the same planetary gear set. Each planetary gear set can be free of elements other than those mentioned here. A rotational axis of a planetary gear set can correspond to a rotational axis of its rotating elements.

[0040] In one embodiment of the drivetrain, the drivetrain may include an all-wheel-drive switching element and a second axle assembly. The first motor shaft can be mechanically connected to the second axle assembly via the all-wheel-drive switching element. This allows a second axle, with, for example, two output elements, to be driven by the first electric motor. This enables the provision of all-wheel drive with minimal effort. An all-wheel-drive connection from the first motor shaft to the second output shaft can be established between the first electric motor and the differential gear in an axial direction of either the first or second output shaft.For example, a spur gear or bevel gear of the all-wheel drive connection can be arranged in the axial direction of the first output shaft between the first electric motor and the differential on the first or second output shaft. The all-wheel drive connection can, for example, include connecting shafts, spur gear stages, bevel gear stages, and, alternatively or additionally, the all-wheel drive shift element, for example, to transmit torque from the first axle assembly to the second axle assembly. The all-wheel drive connection can be provided as an alternative to or in addition to the first pinion connection. Due to the typically large diameter of output elements in agricultural machinery (ZF Friedrichshafen AG file 303681, Friedrichshafen, August 6, 2024), sufficient installation space and ground clearance can be ensured, resulting in a compact design.

[0041] In one embodiment of the drivetrain, the all-wheel drive connection may include a bevel gear stage and a spur gear stage. This allows for a simple transverse connection. A bevel gear stage can, for example, connect two shafts at an angle of 90° to each other.

[0042] A first bevel gear in the bevel gear stage can be permanently and rotationally fixed to the first motor shaft. A second bevel gear in the bevel gear stage can be permanently and rotationally fixed to a spur gear in the spur gear stage. The design of the connection can be simple. For example, the spur gear stage can pass below the first output shaft.

[0043] Alternatively, the first spur gear of the spur gear stage can be permanently and rotationally fixed to the first motor shaft. A second spur gear of the spur gear stage can be permanently and rotationally fixed to a bevel gear of the bevel gear stage. This design allows for a reduced operating speed at the bevel gear drive. It can also simplify assembly, for example, via journals on the second planet carrier. Furthermore, manufacturing the teeth of the first spur gear can be simpler, as the diameter can be smaller. The bevel gear stage, another spur gear stage, or a shaft can, for example, pass below the first output shaft.

[0044] In one embodiment of the drive train, the second axle assembly may comprise at least one of the following components, which may be designed as in the first axle assembly. For example, the second axle assembly may comprise a second electric motor with a second motor shaft, constructed and connected in the same way as the first electric motor. For example, the second axle assembly may comprise a second differential gear, constructed and connected in the same way as the first. (ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06)

[0045] The differential gear is constructed and connected. For example, the second axle assembly can include a third output shaft with an axial length equal to the first. Alternatively, the second axle assembly can include a fourth output shaft with an axial length equal to the second. The axial length of both axle assemblies can be the same and can be selected modularly by choosing the two associated output shafts. The second axle assembly can have a similar or identical design to the first. The aforementioned components can be modularly modifiable, for example, to adapt the track width and power output to different machines.For example, the second axle assembly can also include a second power take-off drive as a component. This second power take-off drive can be designed and arranged in relation to the second axle assembly in the same way as the first power take-off drive. The second power take-off drive can be located at an end of the machine opposite the first power take-off drive. The second power take-off drive can be constructed and operatively connected in the same way as the first power take-off drive. The second power take-off drive can include a second power take-off motor and a second power take-off shaft, which can be driven by the second power take-off motor.

[0046] The second axle arrangement can be similar to or identical to the first axle arrangement, but, for example, without an electric motor. The second axle arrangement can include a third output shaft, a fourth output shaft, and a second differential. These components can be designed like those of the first axle arrangement, allowing for the use of many identical parts. The first motor shaft can be mechanically connected to the third and fourth output shafts via the second differential using the all-wheel-drive shift element. The first motor shaft can also be mechanically connected or operatively coupled to an input shaft of the second differential. In a operatively coupled configuration, the all-wheel-drive shift element can be omitted, providing permanent all-wheel drive. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0047] Alternatively, the second axle assembly features a second electric motor. This second electric motor can be designed like the first electric motor. For example, the same axle assembly can be modularly installed multiple times in the machine. For instance, a second motor shaft of the second electric motor is mechanically connected to the input shaft of the second differential gear.

[0048] This allows for a cost-effective provision of high drive power. The all-wheel drive connection can then be omitted. However, the all-wheel drive connection can still be used for simultaneous braking of both axle configurations.

[0049] In one embodiment of the drivetrain, the all-wheel drive connection may pass the first output shaft and, alternatively or additionally, the second output shaft below the first output shaft. "Below" can be defined by the vehicle's vertical direction. Alternatively or additionally, the all-wheel drive connection may pass the first power take-off connection below the first power take-off connection.

[0050] In one embodiment of the drive train, the first axle assembly may have a modular design in which at least one of the following components is modularly interchangeable for adaptation to the driven machine. For each modularly interchangeable component, there may be, for example, at least two variants. The first output shaft and, alternatively or additionally, the second output shaft may be interchangeable, for example, to adapt to a different track width. The variants may therefore be of different lengths. The connection from the first output shaft to the first output element and, alternatively or additionally, the connection from the second output shaft to the second output element may be interchangeable. This allows for different gear ratios to be provided for adaptation to a different speed range of the driven machine. Furthermore, the connection may be steered or unsteered.This allows for the provision of a steered or unsteered axle. The first differential gear can be modularly interchangeable, for example, for different gear ratios. Similarly, the second axle assembly can have a modular design, with equivalent components being modularly interchangeable for adaptation to the machine (ZF Friedrichshafen AG File 303681, Friedrichshafen, 2024-08-06).

[0051] In one embodiment of the drivetrain, the first sun gear may be permanently and non-rotatably connected to the first motor shaft. The first sun gear may, for example, form the input shaft of the first differential. The first planet carrier may be permanently and non-rotatably connected to the first output shaft. The first planet carrier may, for example, form the first output shaft of the planetary gear set. The second planet carrier may be fixed to a stationary component, such as a vehicle frame or a transmission housing. The second ring gear may be permanently and non-rotatably connected to the second output shaft. The second ring gear may, for example, form the second output shaft of the planetary gear set.By selecting a suitable gear ratio, it is easy to provide the same ratio for both output shafts of the differential, provided, for example, the machine is traveling straight ahead and both output shafts have the same slip. Furthermore, this allows for the easy integration of the first differential lock.

[0052] In one embodiment of the drive train, the differential lock may be designed to connect the first planet carrier to the second ring gear in a rotationally fixed manner.

[0053] In one embodiment of the drivetrain, the drivetrain may have a first service brake designed to brake the first output element. Alternatively or additionally, the drivetrain may have a second service brake designed to brake the second output element. This allows the output elements to be braked individually, enabling additional functions. For example, the two service brakes may be designed as disc brakes or drum brakes on the wheels. Likewise, a third and a fourth service brake may be provided in the second axle arrangement (ZF Friedrichshafen AG File 303681, Friedrichshafen, August 6, 2024), designed analogously to the first and second service brakes.

[0054] In one embodiment of the drivetrain, a central service brake may be provided, which is designed to brake the all-wheel drive connection between the first axle arrangement and the second axle arrangement. This allows all axles to be braked centrally together. This frees up more installation space between the output elements for other components. When the central service brake is applied, the all-wheel drive shift element can, for example, be automatically closed. The all-wheel drive shift element can also be automatically closed when the brakes are applied to individual service brakes at the output elements.

[0055] The powertrain can include an energy storage device for supplying power to the respective electric motors. The energy storage device can be located, for example, centrally in the vehicle's longitudinal direction. It can also be located, for example, in front of the first axle assembly in the vehicle's longitudinal direction. Finally, it can be located, for example, between the first and second axle assemblies in the vehicle's longitudinal direction. The energy storage device can be, for example, a battery or a fuel cell.

[0056] A third aspect concerns a machine. The machine has the drive train as described in the second aspect. The respective advantages and further features can be found in the description of the second aspect, whereby embodiments of the first and second aspects also constitute embodiments of the third aspect and vice versa. The machine's drive power can be provided electrically via the drive train. The machine's power take-off (PTO) output can be provided electrically via the drive train. The PTO output can correspond to the work output. The PTO output can be provided at one or more power take-off shafts. The PTO output and the drive power can be provided independently of each other and can also be adjusted. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0057] Brief description of the characters

[0058] Fig. 1 schematically illustrates in a side view a first embodiment of a working machine with an electrified drive train.

[0059] Fig. 2 schematically illustrates in a top view a second embodiment of a working machine with an electrified drive train.

[0060] Fig. 3 schematically illustrates a differential gear.

[0061] Fig. 4 schematically illustrates a first embodiment of a drive train.

[0062] Fig. 5 schematically illustrates a second embodiment of a drive train.

[0063] Fig. 6 schematically illustrates an arrangement of components of a drive train in a top view.

[0064] Fig. 7 schematically illustrates an arrangement of components of a drive train in a side view.

[0065] Fig. 8 schematically illustrates a front axle of a drive train.

[0066] Fig. 9 schematically illustrates a modular structure of a drive train.

[0067] Fig. 10 schematically illustrates a modular structure of a drive train.

[0068] Fig. 11 schematically illustrates a third embodiment of a drive train.

[0069] Fig. 12 schematically illustrates a fourth embodiment of a drive train. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0070] Fig. 13 schematically illustrates a fifth embodiment of a drive train.

[0071] Fig. 14 schematically illustrates a sixth embodiment of a drive train.

[0072] Fig. 15 schematically illustrates a method for operating the drive train of the working machine.

[0073] Detailed description of embodiments

[0074] Fig. 1 illustrates a first embodiment of a tractor-type work machine in a schematic side view. This work machine has two axles, each with wheels 10 attached to one end, which form the output elements of a drive train. In the embodiment of Fig. 1, a first axle arrangement 12 is shown at the rear. A second axle arrangement 14 is shown at the front. Since a drive motor is arranged coaxially with the associated wheels 10 in the first axle arrangement 12 and optionally in the second axle arrangement 14, there is ample installation space 16 between the two axle arrangements 12, 14 in the longitudinal direction of the vehicle and above the second axle arrangement 14 for an energy storage device for the drive train.

[0075] Figure 2 shows a second embodiment of the tractor-type work machine in a top view. This differs from the first embodiment by the additional all-wheel drive connection 18 between the first axle assembly 12 and the second axle assembly 14. This enables all-wheel drive. The first axle assembly 12 can also drive the second axle assembly 14, allowing a single drive motor to provide all-wheel drive. Furthermore, this enables centralized braking of all wheels 10. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0076] Figure 3 schematically illustrates a differential gear 20, which is used in the two axle arrangements 12 and 14 and enables a space-saving coaxial arrangement. The differential gear has an input shaft 22, a first output shaft 24, and a second output shaft 26, which are arranged coaxially to each other. The two output shafts 24 and 26 are operatively connected to opposing gears 10 on the driven machine. The input shaft 22 is driven by a drive motor, which, in the embodiments shown here, is permanently and rotationally fixed to the input shaft 22. The differential gear has a first planetary gear set 30 with a first sun gear 32, a first planet carrier 34, and a first ring gear 36, as well as a second planetary gear set 40 with a second sun gear 42, a second planet carrier 44, and a second ring gear 46.The first planet carrier 34 has two planet gears 38 rotatably mounted on it, which mesh with the first sun gear 32 and the first ring gear 36. The second planet carrier 44 has two planet gears 48 rotatably mounted on it, which mesh with the second sun gear 42 and the second ring gear 46. The first ring gear 36 is permanently and rotationally fixed to the second sun gear 42, with these being formed integrally by a hollow gear having internal and external teeth. The two planet gear sets 30, 40 are radially stacked, with the second planet gear set 40 arranged radially outside the first planet gear set 30. The second planet carrier 44 is fixed to a stationary component. The first planet carrier 34 forms the first output shaft 24 or is permanently and rotationally fixed to it. The second ring gear 46 forms the second output shaft 26 or is permanently and rotationally fixed to it.The first sun gear 32 forms the input shaft 22 or is permanently and rotationally fixed to it.

[0077] The differential gear 20 has a differential lock 50, which is designed as a friction-fit switching element. The differential lock 50 allows the first planet carrier 34 and the second ring gear 46, and thus also the two output shafts 24, 26, to be connected to each other in a rotationally fixed manner. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0078] Fig. 4 schematically illustrates a first embodiment of a drive train for the previously described embodiments of a working machine. The drive train comprises the first axle assembly 12. The first axle assembly 12 includes a first electric motor 60 with a first motor shaft 62, a first differential gear 20, which is designed like the differential gear 20 shown in Fig. 3, a first output shaft 64, a second output shaft 66, a first output element 68, and a second output element 70. In this embodiment, the first electric motor 60 forms the sole traction motor of the drive train. The first output element 68 forms the right rear wheel 10, and the second output element 70 forms the left rear wheel 10.The first motor shaft 62 is mechanically connected via the differential 20 to the first output shaft 64 and the second output shaft 66, with the first motor shaft 62 being permanently and rotationally fixed to the first sun gear 32. The first sun gear 32 is permanently and rotationally fixed to the first output shaft 64, and the second ring gear 46 is permanently and rotationally fixed to the second output shaft 66. The first motor shaft 62, the first output shaft 64, and the second output shaft 66 are arranged coaxially with each other.

[0079] The first output shaft 64 is mechanically connected to the first output element 68, in the illustrated embodiment via a further planetary gear 72 without a pivot. The second output shaft 66 is mechanically connected to the second output element 70, in the illustrated embodiment via a further planetary gear 72 without a pivot. The first output element 68 can be braked via a first service brake 74, which is connected to the associated planetary gear 72 and is designed as a disc brake. The second output element 70 can be braked via a second service brake 76, which is connected to the associated planetary gear 72 and is designed as a disc brake.

[0080] The drive train of Fig. 4 optionally includes an all-wheel drive switching element 80 and also optionally an all-wheel drive coupling 18. This allows the first motor shaft 62 to be mechanically coupled to the second axle assembly 14. The all-wheel drive switching element 80 is designed as a multi-plate clutch. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0081] The all-wheel drive connection 18 comprises a spur gear stage 84 and a bevel gear stage 82. A first bevel gear 86 of the bevel gear stage 82 is permanently and rotationally fixed to the first motor shaft 62. A second bevel gear 88 of the bevel gear stage 82 is permanently and rotationally fixed to a spur gear of the spur gear stage 84. The spur gear stage 84 comprises a gear 90 which meshes with a spur gear at one axial end and with another spur gear at the opposite axial end. This allows the all-wheel drive connection 18 to be easily guided along the first motor shaft 62 in the longitudinal direction of the vehicle to the second axle assembly 14. The all-wheel drive connection 18 is arranged in the axial direction of the first axle assembly 12 and thus in the transverse direction of the vehicle between the first electric motor 60 and the differential gear 20. The axial direction of the first axis arrangement 12 corresponds to an axial direction of the first output shaft 64.

[0082] Figure 4 does not show a second axle arrangement 14, which may be provided in some embodiments. One possible design of this second axle arrangement 14 is shown in Figure 8, which will be described later.

[0083] The drive train includes a first power take-off (PTO) drive. The PTO drive comprises a first PTO electric motor 92 with a first PTO motor shaft 94 and a first PTO shaft 96. The first PTO electric motor 92 is arranged longitudinally in front of the first axle assembly 12, and the first PTO shaft 96 is located behind the first axle assembly 12. This allows for efficient use of the available installation space. The first PTO shaft 96 protrudes from the rear of the machine for the connection of an implement. The first PTO motor shaft 94 is mechanically connected to the first PTO shaft 96 by a PTO coupling 98. The PTO coupling 98 has several spur gear stages, a planetary gear set 104, a PTO switching element 100, and connecting shafts. The PTO switching element 100 allows the first PTO electric motor 92 to be disconnected from the first PTO shaft 96.The first PTO electric motor 92 drives a main hydraulic pump 102 via spur gear stages, whereby the main hydraulic pump 102 can continue to operate even when the first PTO shaft 96 is to be stationary, thanks to the PTO switching element 100. The first PTO connection 98 extends from the first PTO motor shaft 94 to the first PTO shaft 96 orthogonally to the first axle assembly 12 and thus to the axial direction of the first output shaft 64 between the first electric motor 60 and the differential gear 20. This allows the first PTO connection 98 to pass through the axle assembly 12 in a space-saving manner.

[0084] The first dispensing drive has no mechanical connection with the first axle assembly 12 and the second axle assembly 14, if present. In another embodiment, the first dispensing drive can be decoupled from the first axle assembly 12. If the second axle assembly 14 is present in such an embodiment, the first dispensing drive can then also be decoupled from the second axle assembly 14 or is permanently decoupled.

[0085] Furthermore, the drive train includes a control device 500. The control device 500 has an inverter and connects the respective electric motors 60 of the drive train to an energy storage device 502. The control device 500 can thus control the energy output and therefore the rotational speed of the connected electric motors 60. The control device 500 thus forms a first control device, which is designed to set a travel speed of the working machine by controlling the rotational speed of the first electric motor 60. In addition, the control device 500 thus forms a second control device, which is designed for a speed set by the

[0086] The control device 500 is designed to independently adjust the rotational speed of the first power take-off shaft 96, independent of the driving speed. For this purpose, the control device 500 controls the rotational speed of the first power take-off electric motor 92 and sets the gear ratio of a power take-off gearbox, if present.

[0087] The control device 500 enables the operation of the drive train as illustrated in Fig. 15. In step 600, the travel speed of the machine is set by specifying a rotational speed for the first electric motor 92. In step 602, the rotational speed of the first power take-off shaft 96 is set independently of the set travel speed and thus of step 600 by specifying a rotational speed for the first power take-off electric motor 92. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0088] In one embodiment, a vehicle state is detected in a further step 604. In a step 606, a setting range for the rotational speed of the first power take-off shaft 96 is specified depending on the detected vehicle state. This prevents the setting of a rotational speed of the first power take-off shaft 96 that is impermissible for the vehicle state.

[0089] In one embodiment, the driver can manually adjust the rotational speed of the first power take-off shaft 96 and also the driving speed. In another embodiment, this adjustment is performed alternatively or additionally automatically by an autonomous control system of the drive train.

[0090] In one embodiment, the rotational speed of the first power take-off shaft 96 is set as an absolute value in step 602. In another embodiment, the rotational speed of the first power take-off shaft 96 is always or optionally set as a ratio to the driving speed of the machine. This allows for a variable-speed PTO function.

[0091] The drive arrangement includes three additional electric motors 110, each of which drives an associated pump 112. This allows the control hydraulics, lubrication, and respective switching elements to be supplied with pressure independently of the drive power and work output.

[0092] Fig. 5 schematically illustrates a second embodiment of the drive train, which differs from the first embodiment only in the design of the all-wheel drive connection 18. Therefore, only these differences will be explained.

[0093] Specifically, the all-wheel drive connection 18 also has a spur gear stage 84 and a bevel gear stage 82, which, however, are connected differently. Instead of the bevel gear stage 82, the spur gear stage 84 is now directly connected to the first motor shaft 62. A first spur gear 120 of the spur gear stage 84 is permanently and rotationally fixed to the first motor shaft 62. A second spur gear 122 of the spur gear stage 84 is connected to a ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0094] The bevel gear 124 is permanently and rotationally fixed to the bevel gear stage 82. This results in a lower rotational speed at the bevel gear stage 82 during operation.

[0095] Figure 6 illustrates a possible spatial arrangement of the components of the drive assembly in a top view. Figure 7 illustrates a possible spatial arrangement of the components of the drive assembly in a side view. This spatial arrangement can be used for all embodiments of the drive train and the working machine. Arrow 154 in Figures 6 and 7 illustrates a forward direction of travel with the working machine. In Figure 6, part of a connection to the power take-off shaft 96 is represented symbolically by an arrow. In Figure 7, part of the connection from the power take-off shaft 96 to the power take-off generator 92 is represented symbolically by an arrow. The power take-off generator 92 is not shown in Figure 7. Likewise, the main hydraulic pump 102 is not shown in Figure 7. Furthermore, the control device 500 and the energy storage device 502 are not shown in Figures 6 and 7.

[0096] As can be seen, the all-wheel drive connection 18 and the PTO connection 98 are arranged in an axial direction of the first axle assembly 12 between the differential gear 20 and the first electric motor 60. The differential lock 50 is arranged on the side of the differential gear 20 facing away from the first electric motor 60, although a reverse arrangement is also possible. A connection 150 between the first output shaft 64 and the first output element 68, as well as a connection 150 between the second output shaft 66 and the second output element 70, can be modified modularly, as will be explained below. For example, the connection can be designed as a pivoted link instead of the rigid link shown so far.

[0097] Figure 7 shows that both the all-wheel drive connection 18 and the PTO connection 98 pass under an axis 160 of the first axle arrangement 12, which is a rotation axis of the first output shaft 64, the second output shaft 66, and the first engine shaft 62, in the vehicle's vertical direction. (For simplification, see ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06)

[0098] In Fig. 7, not all shafts of the first axle arrangement 12 are shown.

[0099] Fig. 8 schematically illustrates an embodiment of the second axle assembly 14. As can be seen, the second axle assembly 14 is almost identical to the first axle assembly 12 according to Fig. 4. Identical components are therefore provided with the same reference numeral, even if they are designated differently for identification purposes. In this embodiment, no power take-off (PTO) drive is provided at the front, although a second PTO drive for a front PTO shaft can also be provided. The second axle assembly 14 also has a differential gear 20, which is referred to here as the second differential gear 20. In addition, the second axle assembly 14 has a second electric motor 60 with a second motor shaft 62. The two output elements 68, 70 are each mechanically connected to the second differential gear 20 via a planetary gear 72.The all-wheel drive connection 18 of the second axle arrangement 14 also extends orthogonally between the second electric motor 60 and the differential gear 20 in the transverse direction of the vehicle.

[0100] The two output shafts 24, 26 of the differential 20 are permanently and rotationally fixedly connected to the two output shafts 64, 66 in the second axle arrangement 14. However, the two output shafts 64, 66 are not rigidly connected to the two output elements 68, 70, but rather articulated. For this purpose, a joint 160 is arranged in the rotationally fixed connection between the two output shafts 64, 66 and an input shaft 22 of the associated planetary gear 72. This joint 160 allows the output elements 68, 70, or the left front wheel and the right front wheel 10, to pivot about an axis of the joint 160 extending in the vertical direction of the vehicle. This enables steering at the front axle. Adjacent to the second axle arrangement 14, no all-wheel drive switching element 80 is provided, as one all-wheel drive switching element 80 is sufficient to connect the two axle arrangements 12 and 14. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0101] In the embodiment shown in Fig. 8, the second electric motor 60 is also controlled by the control device 500. Thus, the travel speed of the working machine can be adjusted by controlling the first and second electric motors 60.

[0102] Figures 9 and 10 illustrate a modular design. Figure 9 illustrates three variants of the first axle arrangement 12 and the second axle arrangement 14. In the first variant 200 shown in Figure 9 (top), the two output shafts 64, 66 and, alternatively or additionally, the connection 150 to the output elements 68, 70 are axially shorter. This allows for a drive train with a narrow track gauge, while a central part 210 remains identical. A second variant 202 is shown in the middle of Figure 9, in which the two output shafts 64, 66 and, alternatively or additionally, the connection 150 to the output elements 68, 70 have a normal axial length. This allows for a drive train with a normal track gauge, while a central part 210 remains identical. The track gauge of the first variant 200 is therefore narrower than that of the second variant 202. The axial extent of the central part 210 remains the same. This is shown in the figure below.Figure 9 shows a third variant 204, which has the same track width as the second variant 202. However, the connection 150 to the output elements 68, 70 of the two output shafts 64, 66 each has a joint 160, as in the second axle arrangement 14 in Figure 8. This allows for modular selection of which axles of the machine are steered. For example, rear axle steering can be provided as an alternative or in addition to front axle steering. To provide sufficient installation space for the joints 160, shorter output shafts 64, 66 from the first variant 200 can be used, for example. This further reduces the number of component variants.

[0103] Figure 10 illustrates how the modular design can be used in a machine. A first axle assembly 12 with power take-off (PTO) drive and thus power take-off shaft 96 is shown. This first axle assembly 12 can optionally have the joints 160 for rear-wheel steering, which are therefore shown with dashed lines. The second axle assembly 14 can be coupled to the first axle assembly 12 via the optional all-wheel drive connection 18 and also has the joints 160. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0104] Figure 11 schematically depicts a narrow-gauge variant, or the first variant 200, of the first axle arrangement 12 in detail as the third embodiment of the drive train. The third embodiment of the drive train differs from the first embodiment only in the design of the brake system and the length of the two output shafts 64, 66. Therefore, only these differences are explained, and otherwise the same reference numerals are used. Furthermore, the optional electric motors 110 and pumps 112 are not shown in Figure 11.

[0105] In the third embodiment, the two service brakes 74, 76 are omitted. Instead, the drivetrain has a central service brake 300, which is designed to brake the all-wheel drive connection 18 between the first axle arrangement 12 and the second axle arrangement 14. The all-wheel drive connection 18 is permanently connected to at least one of the two axle arrangements 12, 14, with the central service brake 300 acting on a corresponding shaft. Furthermore, when the central service brake 300 is activated, the all-wheel drive switching element 80 is automatically closed. As a result, the central service brake 300 acts on both the rear axle and the front axle and on all output elements 68, 70. The central service brake 300 requires less axial installation space for the two axle arrangements 12, 14, which allows the central part 210 to have the same design as the wider track despite the narrower track width.

[0106] Figure 12 schematically illustrates a fourth embodiment of the drive train. This fourth embodiment differs from the first only in that the all-wheel drive connection 18 is omitted. Furthermore, both the first axle arrangement 12 and the second axle arrangement 14 are shown, along with their arrangement on a frame 400 of the machine (shown with dashed lines). In one embodiment, this frame 400 also forms a housing for the central part 210.

[0107] Figure 13 schematically depicts a fifth embodiment of the drivetrain. This fifth embodiment differs from the first embodiment (ZF Friedrichshafen AG File 303681, Friedrichshafen, August 6, 2024) in the design of the first power take-off (PTO) connection 98. The PTO switching element 100 is now located on the side of the PTO electric motor 92 relative to the first axle assembly 12, rather than on the side of the PTO shaft 96. Furthermore, the number of spur gears connecting the PTO motor shaft 94 and the main hydraulic pump 102 has been reduced. A central gear of the connecting spur gear stage is permanently and rotationally fixed to an axle extending under the first axle assembly 12. This axle is no longer connected to the PTO shaft 96 via the planetary gear set 104, but rather via a simple spur gear stage.The axial position of the PTO switching element 100 at the rear of the vehicle's longitudinal axis allows for the placement of an oil tank in a front area. Component complexity can be reduced, as a hollow shaft design for the all-wheel drive connection 18 is no longer necessary. Furthermore, increased efficiency is possible due to the reduced number of gear engagements. Additionally, a lower gear ratio may allow for overspeeding of the PTO shaft 96.

[0108] Furthermore, in the fifth embodiment, the design of the planetary gear sets 72 differs, each of which mechanically connects the two output elements 68, 70 to the second differential gear set 20. Instead of a planetary gear set with planet gears of simple teeth, stepped planetary gear sets are now provided. The stepped planetary gear sets have a first tooth that meshes only with the sun gear. The stepped planetary gear sets have a second tooth that meshes only with the ring gear and which has a smaller effective diameter than the first tooth. With the same radial diameter, this design of the planetary gear set 72 can have a higher gear ratio. In addition, in the fifth embodiment, the all-wheel drive connection is designed as in the second embodiment or as shown in Fig. 5.

[0109] Figure 14 schematically illustrates a sixth embodiment of the drive train. This sixth embodiment differs from the fifth embodiment in the design of the operative connection between the PTO motor shaft 94 and the main hydraulic pump 102. In the sixth embodiment (ZF Friedrichshafen AG File 303681, Friedrichshafen, August 6, 2024), this operative connection is not provided by three spur gears, with a central spur gear meshing with both a motor-side and a pump-side spur gear, as in the fifth embodiment. Instead, this operative connection is provided by four spur gears, with two spur gears meshing with each other and two of these spur gears, located centrally in the power flow, being permanently and rotationally fixed together. In the fifth embodiment, the number of spur gears is small, resulting in high efficiency in driving the main hydraulic pump 102.In the sixth embodiment, the radial installation space required for the functional connection to the main hydraulic pump 102 is small, and an axial offset can be easily provided. Furthermore, a high gear ratio for driving the main hydraulic pump 102 can be provided in this way, even with a small installation space requirement.

[0110] ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0111] Reference sign

[0112] 10 front and rear wheels

[0113] 12 first axle arrangement

[0114] 14 second axle arrangement

[0115] 16 construction space

[0116] 18 All-wheel drive connection

[0117] 20 Differential gears

[0118] 22 Input wave

[0119] 24 first output wave

[0120] 26 second output wave

[0121] 30, 40, 104 planetary gear set

[0122] 32 first sun wheel

[0123] 34 first planetary carrier

[0124] 36 first ring gear

[0125] 38 first planetary gears

[0126] 42 second sun wheel

[0127] 44 second planetary carrier

[0128] 46 second ring gear

[0129] 48 second planetary gears

[0130] 50 Differential lock

[0131] 60, 110 electric machine(s)

[0132] 62 Motor shaft

[0133] 64 first output shaft

[0134] 66 second output shaft

[0135] 68 first output element

[0136] 70 second output element

[0137] 72 planetary gears

[0138] 74, 76, 300 Service brake

[0139] 80 All-wheel drive switching element

[0140] 82 bevel gear stage

[0141] 84 Spur gear stage

[0142] 86, 88, 124 bevel gear

[0143] 90 Gear ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06

[0144] 92 dispensing electromechanical

[0145] 94 PTO shaft

[0146] 96 PTO

[0147] 98 Tap connection

[0148] 100 dispensing switch elements

[0149] 102 Main hydraulic pump

[0150] 112 pump(s)

[0151] 120 first spur gear

[0152] 122 second spur gear

[0153] 150, 152 connection

[0154] 154 Arrow

[0155] 160 axles / joints

[0156] 200, 202, 204 variant

[0157] 210 Central part

[0158] 400 frames

[0159] 500 control device

[0160] 502 Energy storage

[0161] 600 steps of adjusting the driving speed

[0162] Step 602 of setting the rotation speed of the first

[0163] PTO

[0164] Step 604 of recording the vehicle condition

[0165] Step 606 of specifying the setting range

Claims

ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06 Patent claims 1. Method for operating a drive train of a working machine, wherein the drive train comprises at least a first electric machine (60) with a first motor shaft (62) for driving a first axle assembly (12) and at least a first power take-off electric machine (92) with a first power take-off motor shaft (94) for driving a first power take-off shaft (96) of a first power take-off drive, wherein the power take-off drive and the first axle assembly (12) are decoupled in at least one state of the drive train, wherein the method comprises at least the following steps: - Setting (600) a travel speed of the working machine; and - Setting (602) a rotational speed of the first power take-off shaft (96) independently of the set driving speed.

2. The method according to claim 1, characterized in that the method further comprises the following steps: - A vehicle condition assessment (604); and - A specification (606) of an adjustment range for the rotational speed of the first power take-off shaft (96) depending on the detected vehicle condition.

3. Method according to claim 1 or 2, characterized in that the adjustment (602) of the rotational speed of the first power take-off shaft (96) is carried out automatically.

4. Method according to claim 1 or 2, characterized in that the adjustment (602) of the rotational speed of the first power take-off shaft (96) is carried out manually.

5. Method according to one of the preceding claims, characterized in that the rotational speed of the first power take-off shaft (96) is set as a ratio to the driving speed of the working machine. ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06 6. Method according to one of the preceding claims, characterized in that the first dispensing drive and the first axle arrangement (12) are permanently decoupled.

7. Method according to one of claims 1 to 5, characterized in that the method comprises a step of adjusting the drive train to the state in which the first PTO drive and the first axle arrangement (12) are decoupled.

8. Drive train of a working machine, wherein the drive train comprises at least a first electric machine (60) with a first motor shaft (62) for driving a first axle assembly (12) and at least a first power take-off electric machine (92) with a first power take-off motor shaft (94) for driving a first power take-off shaft (96) of a first power take-off drive, wherein the power take-off drive and the first axle assembly (12) are decoupled in at least one state of the drive train, wherein the drive train comprises a first control device (500) configured for setting (600) a travel speed of the working machine, and wherein the drive train comprises a second control device configured for setting (602) a rotational speed of the first power take-off shaft (96) independently of the set travel speed.

9. Drive train according to claim 8, wherein the drive train comprises the first axle assembly (12) and the first power take-off (PTO) drive, wherein the first axle assembly (12) comprises the first electric motor (60) with the first motor shaft (62), a first differential gear (20), a first output shaft (64), a second output shaft (66), a first output element (68) and a second output element (70), wherein the first PTO drive comprises the first PTO electric motor (92) with the first PTO motor shaft (94) and the first PTO shaft (96), wherein the first motor shaft (62) is mechanically connected to the first output shaft (64) and the second output shaft (66) via the differential gear (20), wherein the first motor shaft (62) is arranged coaxially to the first output shaft (64), and wherein the first output shaft (64) is mechanically connected to the first output element (68). is, whereby the second output shaft ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06 (66) is mechanically operatively connected to the second output element (70), wherein the first differential gear (20) comprises a first differential lock (50), a first planet gear set (30) with a first sun gear (32), a first planet carrier (34) and a first ring gear (36) and a second planet gear set (40) with a second sun gear (42), a second planet carrier (44) and a second ring gear (46), wherein the first ring gear (36) is permanently rotationally fixed to the second sun gear (42) and the two planet gear sets (30, 40) are radially stacked, wherein the first power take-off motor shaft (94) is mechanically operatively connected to the first power take-off shaft (96), wherein a first power take-off operative connection (98) from the first power take-off motor shaft (94) to the first power take-off shaft (96) extends transversely to the first output shaft (64) between the first electric machine (60) and the differential gear (20) extends in an axial direction of the first output shaft (64).

10. Drive train according to claim 9, characterized in that the drive train has an all-wheel drive switching element (80) and a second axle arrangement (14), wherein the first motor shaft (62) can be mechanically connected to the second axle arrangement (14) by means of the all-wheel drive switching element (80), wherein an all-wheel drive connection (18) from the first motor shaft (62) to the second axle arrangement (14) is connected between the first electric motor (60) and the differential gear (20) in an axial direction of the first output shaft (64) to the first output shaft (64).

11. Drive train according to claim 10, characterized in that the second axle arrangement (14) comprises at least one of the following components: - A second electric machine (60) with a second motor shaft (62), which is constructed and connected in the same way as the first electric machine (60); - A second differential gear (20); - A third output shaft; and - A fourth output shaft.

12. Drive train according to claim 10 or 11, characterized in that the first sun gear (32) is permanently rotationally fixed to the first motor shaft (62), and the first planet carrier (34) is permanently fixed to the first output shaft (64). ZF Friedrichshafen AG File 303681 Friedrichshafen 2024-08-06 is connected in a rotationally fixed manner, the second planet carrier (44) is fixed to a stationary component, and the second ring gear (46) is permanently connected to the second output shaft (66) in a rotationally fixed manner.

13. Working machine with a drive train according to one of claims 8 to 12, characterized in that a driving force of the working machine can be provided electrically by means of the drive train and a power take-off of the working machine can be provided electrically by means of the drive train.

Images