drive system for a vehicle

Abstract

The invention relates to a drive system for a vehicle, comprising at least one first electric machine (2) that can be coupled to, or is coupled to, at least one first wheel (4) of the vehicle to drive it, at least one first hydraulic machine (12) that can be coupled to, or is coupled to, at least one second wheel (14) of the vehicle to drive it, and a supply system comprising at least one power source (10, 18), an electrical network (6), a second electric machine (8), and a second hydraulic machine (16). The electrical network (6) is electrically connected to the at least one first electric machine (2) and the at least second electric machine (8), and the second hydraulic machine (16) is hydraulically connected to the at least one first hydraulic machine (12).The second electric machine (8) is coupled to the second hydraulic machine (16), and the at least one power source (10, 18) is connected to the electrical network (6) to provide electrical power, and / or is coupled or can be coupled to the second electric machine (8) and the second hydraulic machine (16) to drive them.

Description

[0001] The present invention relates to a drive system for a vehicle. Background of the invention

[0002] Certain work or agricultural machines are used, on the one hand, in situations with simple driving conditions, such as driving on level ground over a firm surface, and on the other hand, in situations with demanding traction conditions and / or high drive power requirements. The latter can be the case, for example, on rough terrain, inclines, soft, wet, or loose soils, or similar conditions. Disclosure of the invention

[0003] According to the invention, a drive system for a vehicle with the features of claim 1 is proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

[0004] The invention makes use of the measure of providing in the drive system at least one first electric machine which can be coupled or is coupled to one of at least one first wheel of the vehicle, and at least one first hydraulic machine which can be coupled or is coupled to one of at least one second wheel of the vehicle.The drive system further includes a supply system comprising at least one power source, an electrical network, a second electric machine and a second hydraulic machine, wherein the electrical network is electrically connected to the at least one first electric machine and the at least second electric machine, wherein the second hydraulic machine is hydraulically connected to the at least one first hydraulic machine, wherein the second electric machine is coupled to the second hydraulic machine, and wherein the at least one power source is connected to the electrical network to provide electrical power and / or is coupled or can be coupled to the second electric machine and the second hydraulic machine to drive them.

[0005] The design of the drive system with at least one electrically driven wheel and at least one hydraulically driven wheel, supplied with power or energy by a common supply system, is advantageous because, typically, an electric drive for wheels is more energy-efficient than a hydraulic drive for wheels, and the components of a hydraulic drive for wheels are less expensive than those of an electric drive. For example, through suitable control, efficient operation is enabled for typical power requirements (such as driving on level ground), and additional power can be provided cost-effectively for temporarily high power requirements (such as driving on rough terrain and / or slopes). The individually driven wheels eliminate the need for a continuous axle or...The shaft between paired wheels can be omitted, allowing for high ground clearance or space between wheels.

[0006] For example, in relatively undemanding situations (e.g., low required propulsion power and / or driving on level ground and / or driving on a surface with high traction), the drive system uses only the electrically driven wheels, and in more demanding situations (e.g., higher required propulsion power and / or driving in rough terrain, such as with ramps of higher gradient, and / or driving on a surface with low traction, such as in wet conditions and / or on loose soil), the hydraulically driven wheels are engaged or also driven in the manner of an all-wheel drive.

[0007] The vehicle may be, for example, a work machine and / or an agricultural vehicle or farm machinery, in particular a vehicle where the drive of individual wheels (independent of other wheels) is desirable, e.g. to enable driving in rough terrain or to achieve high ground clearance, such as in the case of a field sprayer.

[0008] Unless otherwise specified, the terms "coupled" and "coupled" are to be understood as referring to a rotationally fixed connection or coupling of rotatable or rotating components (e.g., drive and / or output shafts) of the respective elements. "Rotationally fixed" means that rotations of one component are converted into corresponding (proportional) rotations of the other component, with a transmission ratio that may be equal to or not equal to one. The coupling can be achieved, for example, by means of shafts and / or gears and / or couplings (such as jaw couplings or friction couplings). The term "hydraulically connected" means that a hydraulic line, hydraulic channel, or similar is provided through which a flow of hydraulic fluid is possible between hydraulically connected elements. Valves or similar devices may be provided to control this flow.Each of the at least one first and one second electrical machine is connected to the electrical grid via its own inverter. The inverter of each electrical machine is controlled accordingly.

[0009] According to an embodiment in which the vehicle has at least one additional hydraulic consumer and a valve arrangement, the valve arrangement is hydraulically connected to the second hydraulic machine and the at least one additional hydraulic consumer and is configured to control the flow of hydraulic fluid from the second hydraulic machine to the at least one additional hydraulic consumer. The term "at least one additional hydraulic consumer" is intended to denote a hydraulic consumer provided on the vehicle that is different from the at least one first hydraulic machine (which can also be considered a hydraulic consumer). The at least one additional hydraulic consumer is, for example, a hydraulic cylinder or a hydraulic motor used to move a component of the vehicle, such as within the framework of a working hydraulic system. The second hydraulic machine can be, for example, a hydraulic cylinder or a hydraulic motor.It is intended primarily for supplying at least one additional hydraulic consumer or the working hydraulics.

[0010] According to one embodiment, the at least one power source comprises a battery that is electrically connected to the electrical grid. A battery with a relatively low capacity can, for example, be used in addition to another power source, such as an internal combustion engine, to absorb power peaks and / or recuperate energy (e.g., during braking). A battery with a relatively high capacity can, for example, be used as the sole power source or as the primary power source, in which case an additional power source, such as an internal combustion engine, may be present that can be switched on temporarily to recharge the battery.

[0011] According to one embodiment, the at least one power source comprises an internal combustion engine, in particular a diesel engine, which is coupled or can be coupled to the second electric machine and the second hydraulic machine. This embodiment allows the internal combustion engine to drive the second electric machine to provide electrical power in the electrical network and / or to drive the second hydraulic machine to provide a volume flow of hydraulic fluid.

[0012] According to one embodiment, the internal combustion engine, the second electric machine and the second hydraulic machine are permanently coupled to each other by a transmission device or coupling device or a common shaft.

[0013] According to one embodiment, the power supply system includes a coupling device through which the second electric machine and the second hydraulic machine are coupled. This device is configured to controllably couple or decouple the internal combustion engine from the second electric machine and the second hydraulic machine. This embodiment allows for the selective coupling or decoupling of the internal combustion engine. For example, if a battery is provided in at least one power source, this makes it possible to engage or couple the internal combustion engine only when the battery's state of charge falls below a predetermined minimum level. The battery can then be recharged. When the internal combustion engine is decoupled (and can therefore be stopped), the power in the drive system is supplied by the battery.

[0014] According to one embodiment, the supply system includes a third electric machine that is electrically connected to the electrical grid, wherein the at least one power source comprises an internal combustion engine, in particular a diesel engine, which is coupled to the third electric machine. According to this embodiment, two electric machines are provided in the supply system, one of which (namely the second electric machine) drives the second hydraulic machine or is driven by it in situations where the latter acts as a hydraulic motor (e.g., during braking), and the other (namely the third electric machine) is driven by the internal combustion engine to supply electrical energy to the electrical grid. This ensures that the rotational speeds of the second hydraulic machine and the internal combustion engine are independent of each other.This is advantageous because, especially when a battery is used, the combustion engine can always be operated at the most optimal speed (at which, for example, the highest efficiency is achieved) or can be temporarily stopped (for example, when the battery has reached at least a predetermined state of charge, e.g., 80% of its maximum possible charge). Furthermore, the flow rate of the second hydraulic machine can be varied via the speed of the second electric machine, so that, in particular, a constant-displacement hydraulic machine can be used, which are typically less expensive and smaller than variable-displacement hydraulic machines.

[0015] According to one embodiment, the at least one first electric machine includes two first electric machines that can be coupled to, or are coupled to, two corresponding first wheels of the vehicle, wherein the two corresponding first wheels are assigned to a common first vehicle axle, and / or the at least one first hydraulic machine includes two first hydraulic machines that can be coupled to, or are coupled to, two corresponding second wheels of the vehicle, wherein the two corresponding second wheels are assigned to a common second vehicle axle. The two corresponding first wheels are driven independently of each other (by the respective first electric machine coupled to them), i.e., they are not connected to each other by a shaft or via a differential.The two corresponding second wheels are driven independently of each other (by their respective coupled first hydraulic machines), meaning they are not connected to each other by a shaft or differential. The two first and / or second wheels are, for example, two wheels located on opposite sides of the vehicle (left and right wheels).

[0016] According to one embodiment, the second hydraulic machine has an adjustable displacement. This embodiment is particularly advantageous if the second hydraulic machine is driven by an internal combustion engine, which is also coupled to the second electric machine, for example, and / or if additional hydraulic consumers are provided. The term "displacement" refers to the volume of hydraulic fluid delivered by the hydraulic machine per revolution.

[0017] According to one embodiment, the at least one first hydraulic machine has an adjustable displacement, wherein the displacement is particularly adjustable to zero. This secondary-side adjustment capability allows the rotational speed and / or torque of the at least one first wheel coupled to the at least one first hydraulic machine to be controlled or regulated. In the case of multiple first wheels (e.g., the left and right wheels of a vehicle axle, where the two wheels are not connected by a shaft or differential), the rotational speed and / or torque for different first wheels can be controlled or regulated independently of one another. The term "adjustable to zero" means that, for a given direction of rotation, depending on the sign of the displacement (which is given, for example, as a swivel angle or as a percentage of a maximum displacement), hydraulic fluid can be applied in both directions (e.g.,(between a tank connection and a pressure connection of the hydraulic machine) can be conveyed by the hydraulic machine. Accordingly, at least one second wheel can be driven in both directions of rotation.

[0018] According to one embodiment, the drive system further comprises an electronic control system designed to control the supply system and / or the at least one first electrical machine and / or the at least one first hydraulic machine.

[0019] According to one embodiment, the electronic control system is configured to perform speed control and / or torque control of the at least one first electric machine and / or the at least one first hydraulic machine, wherein, in particular, the at least one first electric machine or its inverter and the at least one first hydraulic machine are controlled in such a way as to achieve a target speed and / or acceleration for the vehicle. The target speed and / or acceleration for the vehicle can, for example, be determined from an operator input, which is detected, for example, by a pedal or a joystick.

[0020] According to one embodiment, the electronic control system is configured to implement a first drive mode and a second drive mode. In the first drive mode, the at least one first electric machine is activated so that the at least one first wheel is driven, or so that torque is exerted on the at least one first wheel by the at least one first electric machine, and the at least one first hydraulic machine and / or the second hydraulic machine are activated so that the at least one second wheel is not driven, or so that no torque is exerted on the at least one second wheel by the at least one first hydraulic machine. In the second drive mode, the at least one first electric machine is activated so that the at least one first wheel is driven, or so that torque is not exerted on the at least one second wheel by the at least one first hydraulic machine.so that torque is exerted on the at least one first wheel by the at least one first electric machine, and the at least one first hydraulic machine and / or the second hydraulic machine are controlled so that the at least one second wheel is driven, or so that torque is exerted on the at least one second wheel by the at least one first hydraulic machine. The first drive mode is an energy-efficient drive mode that can be used in situations where relatively little drive power is required. The second drive mode is an all-wheel or multi-wheel drive mode that can be used in situations where relatively high drive power is required.

[0021] According to one embodiment, the electronic control system is configured to perform transitions between the first and second drive modes in response to operator input and / or automatically. Operator input can be captured, for example, via a suitable user interface.

[0022] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0023] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0024] The invention is schematically illustrated in the drawing using exemplary embodiments and is described in detail below with reference to the drawing. Character description Fig. Figure 1 shows a drive system for a vehicle in which energy is provided by an internal combustion engine, according to an embodiment of the invention. Fig. Figure 2 shows a drive system for a vehicle in which energy is provided by a battery, according to a further embodiment of the invention. Detailed description of the drawing

[0025] Fig. Figure 1 shows a drive system for a vehicle in which energy is provided by an internal combustion engine, according to one embodiment of the invention. The vehicle (not shown in detail) can be, for example, a construction machine or an agricultural machine, such as a field sprayer.

[0026] The drive system comprises two first electric machines 2, each coupled to a respective first wheel 4 of the vehicle to drive it. During braking, for example, it is also possible for a wheel 4 to drive the electric machine 2 coupled to it. The coupling between each first electric machine and its associated wheel is rotationally fixed, e.g., via a shaft and / or a gearbox. A (first) inverter 3 (or power converter) is provided for each first electric machine 2, supplying it with alternating current. The inverters 3 are electrically connected to an electrical network 6 carrying a direct current voltage, i.e., connected to the network's electrical lines.

[0027] Two first electric machines 2 and two first wheels 4 are shown as examples. In general, at least one first electric machine (and at least one inverter) is provided, which can be coupled to, or is coupled to, one of at least one first wheel of the vehicle in order to drive it. With multiple first wheels, the first wheels are driven independently of each other by their respective first electric machines. With multiple first machines and first wheels, the first wheels 4 can be assigned in pairs to a vehicle axle (e.g., the front or rear axle of the vehicle), wherein the two wheels of a pair are not coupled to each other, e.g., by a shaft and / or a transmission (such as a differential gear), and are driven independently of each other by their respective first electric machines.

[0028] Furthermore, a second electric machine 8 is provided, which is electrically connected to the electrical network 6 via a (second) inverter 9. The second electric machine 8 provides electrical energy to the electrical network 6 (and thus to at least one first electric machine 2). For this purpose, the second electric machine 8 is driven by an internal combustion engine 10, in particular a diesel engine, to which the second electric machine 8 is coupled via a coupling device 24.

[0029] In addition to the electrically driven first wheels 4, the drive system has two second wheels 14, each of which is coupled (non-rotatably) to a first hydraulic machine 12 in order to be driven by it. Here, too, two first hydraulic machines and two second wheels are shown as examples, whereby in general at least one first hydraulic machine 12 is provided which can be coupled to, or is coupled to, one of at least one second wheel 14 of the vehicle in order to drive it, whereby it may occur that in certain situations, such as during braking, the wheel drives the hydraulic machine coupled to it.

[0030] The at least one first hydraulic machine 12 has, in particular, an adjustable displacement. The term displacement (or volumetric volume or delivery volume) refers to the volume of hydraulic fluid (hydraulic fluid, in particular hydraulic oil) delivered per revolution by the hydraulic machine. The adjustability enables (secondary-side) control or regulation of the speed and / or torque. Furthermore, the displacement of the at least one hydraulic machine 12 can be set to zero, so that (with the same direction of hydraulic fluid flow through the hydraulic machine) different directions of rotation can be achieved. The at least one hydraulic machine 12 is, for example, an axial piston machine in a swashplate or swashplate design, where the displacement corresponds to a swivel angle.

[0031] The hydraulic fluid supply is provided by a (primary-side) second hydraulic machine 16, which is also coupled to the internal combustion engine 10 (and the second electric machine 8) via the coupling device 24 in order to be driven by the internal combustion engine 10. The second hydraulic machine 16 can have an adjustable displacement and can also be zeroed. A pressure port of the second hydraulic machine 16 is connected via hydraulic connections (hydraulic lines, channels, etc.) to pressure ports of the first hydraulic machines 12. Tank ports of the first hydraulic machines 12 and the second hydraulic machine 16 are connected to a tank for hydraulic fluid. This forms a hydrostatic drive for the second wheels 14.

[0032] Analogous to the first wheels, if there are multiple second wheels, the second wheels are driven independently of each other by their respective first hydraulic machine. With multiple second machines and second wheels, the second wheels can be assigned in pairs to a vehicle axle (e.g., the front or rear axle of the vehicle), whereby the two wheels of a pair are not coupled to each other, e.g., by a shaft and / or a transmission (such as a differential gear), and are driven independently of each other by their respective first hydraulic machine.

[0033] The coupling device 24, by which the internal combustion engine 10, the second electric machine 8, and the second hydraulic machine 16 are coupled to one another, comprises, for example, several gears that are connected to the respective output and input shafts of the internal combustion engine 10, the second electric machine 8, and the second hydraulic machine 16. Thus, a rotationally fixed coupling exists, with potentially different gear ratios between these three elements. Of course, other coupling configurations are also possible. For example, two or all three of the elements can be coupled via a common shaft (which can be a single piece or consist of several longitudinally coupled partial shafts).

[0034] The internal combustion engine 10, the second electric machine 8, the second hydraulic machine 16, the coupling device 24 and the electrical network 6 together form a supply system with which the at least one first electric machine 2 and the at least one first hydraulic machine 12 are supplied with electrical or hydraulic energy or power.

[0035] In addition to the at least one first hydraulic machine 12 (which can be considered the vehicle hydraulics), representing a hydraulic consumer, at least one further hydraulic consumer 22 can be connected to the second hydraulic machine 16 (more precisely, to its pressure connection) via a valve arrangement 20. The at least one further hydraulic consumer 22, here exemplified as a hydraulic cylinder, can more generally be, for example, at least one hydraulic cylinder and / or at least one hydraulic motor. The at least one further hydraulic consumer 22 is coupled to a respective movable component (not shown) of the vehicle (e.g., a boom or similar) and serves to effect its movement. The at least one further hydraulic consumer 22 can therefore be considered working hydraulics.The flow of hydraulic fluid to and optionally from at least one further hydraulic consumer 22 is controlled by the valve arrangement 20. Accordingly, the supply system serves to supply hydraulic fluid not only to the at least one first hydraulic machine 12 but also to the at least one further hydraulic consumer 22.

[0036] The drive system can further include an electronic control unit 30 (control device) configured to control the power supply system (i.e., some or all of its elements), the at least one first electric machine 2 or its inverter 3, and the at least one first hydraulic machine 12. The electronic control unit 30 can control the power supply system, the at least one first electric machine 2 or its inverter 3, and the at least one first hydraulic machine 12 such that a speed and / or acceleration target is achieved. The speed and / or acceleration target can be determined by the electronic control unit 30 and / or a higher-level control system, for example, from operator input acquired via a user interface (e.g., a pedal or a joystick), and / or by an automatic driving function (e.g.,The speed control function (or cruise control) can be determined. If at least one further hydraulic consumer 22 or the valve arrangement 20 is provided, the electronic control 30 can be further configured to control the valve arrangement 20.

[0037] The electronic control unit 30 is specifically designed to implement a first drive mode and a second drive mode. In the first drive mode, only the at least one first wheel 4 is driven; that is, the at least one first electric machine 2 or its inverter 3 is controlled such that the entire propulsive force or the torque required to achieve the specified speed and / or acceleration is provided by the at least one first electric machine 2. The at least one first hydraulic machine 12 is controlled such that its displacement is reduced to zero (or to a value slightly different from zero, determined to compensate for any braking frictional torque of the at least one first hydraulic machine) or so that it does not generate any torque.

[0038] In the second drive mode (“all-wheel drive”), both the at least one first wheel 4 and the at least one second wheel 14 are driven; that is, the driving force or the torque required at the wheels to achieve the specified speed and / or acceleration is generated partly by the at least one first electric machine 2 and partly by the at least one first hydraulic machine 12. The distribution of the total driving force or torque between the at least one first wheel 4 and the at least one second wheel 14 can be fixed or varied within certain limits depending on the requirements.

[0039] The transition between the first and second drive modes can occur in response to operator input (e.g., via a switch, a button on a touchscreen, or similar) and / or automatically. For the latter, the electronic control unit 30 can be configured to compare the necessary propulsive force or torque at the wheels to achieve the set speed and / or acceleration, or the torque to be applied by the at least one first electric machine, with a predetermined threshold value, which corresponds to a predetermined portion (e.g., in the range between 75% and 100%) of the maximum torque that can be applied by the at least one first electric machine, and, if the threshold value is exceeded, to switch to the second drive mode.If, for example, the threshold value – optionally minus a (positive) hysteresis (given as a relative or absolute value) – is undershot again, the system reverts to the first drive mode. Alternatively or additionally, it can be determined (e.g., using sensor signals, such as from speed sensors, or based on inverter control data) whether slippage occurs at a first wheel, i.e., whether the wheel's rotational speed, given a specific wheel diameter, does not correspond to the vehicle speed and is, in particular, too high. If this is the case, the system can switch from the first to the second drive mode. An automatic transition from the first to the second drive mode can be indicated by a display device (such as a light or a touchscreen), whereby the transition from the second to the first drive mode can then occur, in particular, in response to operator input.This is useful if, on the one hand, the transition from the first to the second drive mode occurs automatically or the condition for it can be automatically detected, and if, on the other hand, the transition from the second to the first drive mode does not occur automatically or the condition for it cannot be automatically detected.

[0040] Fig. Figure 2 shows a drive system for a vehicle in which energy is provided by a battery, according to a further embodiment of the invention. The drive system of the Fig. 2 largely corresponds to that of the Fig. 1, so that only differences will be discussed below, and otherwise the description of the Fig. 1 is referred to.

[0041] Unlike the Fig. 1. The energy supply in the drive system of the Fig. 2. by an electric battery instead of an internal combustion engine. Accordingly, the power supply system of the drive system features Fig. 2. An electric battery 18 is connected to the electrical grid. The second electric machine 8 is coupled to the second hydraulic machine 16 (here, for example, via a shaft, although a gearbox could also be provided) to drive it. The at least one electric machine 2 and the second electric machine 8, or rather their inverters 3, 9, are supplied with electrical energy from the battery 18 via the electrical grid 6. During braking, the at least one electric machine 2 can act as a generator and feed electrical energy into the electrical grid 6 via the inverter 3. This energy is used to recharge the battery, for example, when the second electric machine 8 requires little or no electrical energy.Situations may also occur (braking process, no further consumer or no flow rate requirement of at least one further consumer) in which the second hydraulic machine 16 acts as a hydraulic motor and drives the electric machine 8, so that this feeds electrical energy into the electrical network 6 and the battery 18.

[0042] It is also possible to customize the design of the Fig. 1 and Fig. 2 to combine, i.e. in addition to the embodiment of the drive system of Fig. 1 an electric battery 18, as in Fig.2. The electric battery 18 can then be used to store electrical energy recuperated during braking and / or to absorb peak loads. The electric battery 18 can be charged by the combustion engine 10 via the second electric machine, for example, when there are low drive power requirements, such as when the battery's state of charge (e.g., expressed as a percentage of a maximum state of charge) falls below a minimum state of charge.

[0043] Furthermore, if an internal combustion engine and an electric battery are provided, the coupling device 24 can be designed or constructed such that the internal combustion engine 10 can be selectively or controllably decoupled from the second electric machine 8 and the second hydraulic machine 16, e.g., controlled by the electronic control unit 30, whereby (when the internal combustion engine is decoupled) the second electric machine 8 and the second hydraulic machine 16 remain coupled. This allows the supply system to operate, for example, such that when the internal combustion engine 10 is decoupled, and in particular when switched off or stopped, the energy is supplied by the battery 18. If the battery's state of charge (e.g.,If the battery charge level (expressed as a percentage) falls below a minimum level, the combustion engine is re-engaged and, in particular, restarted. This allows the second electric machine 8 and its inverter 9 to supply electrical energy to the electrical grid, thereby charging the battery 18, for example, until a predetermined state of charge (e.g., above 80% or 90% of the maximum state of charge) is reached. The combustion engine can then be disengaged and, in particular, stopped. This configuration, as well as the one described above, makes it possible to operate the combustion engine within a power range (speed / torque) in which it exhibits high efficiency.

[0044] The battery and the combustion engine of the aforementioned embodiments constitute power sources and energy sources, respectively, for the drive system. In general terms, the supply system thus has at least one power source that is connected to the electrical grid to provide electrical power and / or that is coupled or can be coupled to the second electric machine and the second hydraulic machine to drive them.

Claims

[1] Propulsion system for a vehicle comprising at least one first electric machine (2) which can be coupled to or is coupled to at least one first wheel (4) of the vehicle in order to drive it; at least one first hydraulic machine (12) which can be coupled to or is coupled to at least one second wheel (14) of the vehicle in order to drive it; A supply system comprising at least one power source (10, 18), an electrical network (6), a second electrical machine (8), and a second hydraulic machine (16); wherein the electrical network (6) is electrically connected to the at least one first electrical machine (2) and the at least second electrical machine (8); wherein the second hydraulic machine (16) is hydraulically connected to the at least one first hydraulic machine (12); wherein the second electrical machine (8) is coupled to the second hydraulic machine (16); and wherein the at least one power source (10, 18) is connected to the electrical network (6) to provide electrical power and / or is coupled or connectable to the second electrical machine (8) and the second hydraulic machine (16) to drive them. [2] Drive system according to claim 1, wherein the vehicle has at least one further hydraulic consumer (22) and a valve arrangement (20); wherein the valve arrangement (20) is hydraulically connected to the second hydraulic machine (16) and the at least one further hydraulic consumer (22) and is configured to control a flow of hydraulic fluid from the second hydraulic machine (16) to the at least one further hydraulic consumer (22). [3] Drive system according to claim 1 or 2, wherein the at least one power source comprises a battery (18) which is electrically connected to the electrical network. [4] Drive system according to one of claims 1 to 3, wherein the at least one power source comprises an internal combustion engine (10), in particular a diesel engine, which is coupled or can be coupled to the second electric machine (8) and the second hydraulic machine (16). [5] Drive system according to claim 4, wherein the internal combustion engine (10), the second electric machine (8) and the second hydraulic machine (16) are permanently coupled to each other by a transmission device or coupling device (24) or a common shaft. [6] Drive system according to claim 4, wherein the supply system has a coupling device (24) by which the second electric machine (8) and the second hydraulic machine (16) are coupled and which is configured to couple or decouple the internal combustion engine (10) with the second electric machine (8) and the second hydraulic machine (16) in a controllable manner. [7] Drive system according to one of claims 1 to 3, wherein the supply system comprises a third electric machine which is electrically connected to the electrical network (6); and wherein the at least one power source comprises an internal combustion engine (10), in particular a diesel engine, which is coupled to the third electric machine. [8] Drive system according to one of the preceding claims, wherein the at least one first electric machine (2) includes two first electric machines which can be coupled or are coupled to two corresponding first wheels (4) of the vehicle, wherein the two corresponding first wheels (4) are assigned to a common first vehicle axle; and / or wherein the at least one first hydraulic machine (12) includes two first hydraulic machines which can be coupled or are coupled to two corresponding second wheels (14) of the vehicle, wherein the two corresponding second wheels (14) are assigned to a common second vehicle axle. [9] Drive system according to one of the preceding claims, wherein the second hydraulic machine (16) has an adjustable displacement. [10] Drive system according to one of the preceding claims, wherein the at least one first hydraulic machine (12) has an adjustable displacement, wherein the displacement is in particular adjustable to zero. [11] Drive system according to one of the preceding claims, comprising an electronic control (30) configured to control the supply system and / or the at least one first electrical machine (2) or its inverter (3) and / or the at least one first hydraulic machine (12). [12] Drive system according to claim 11, wherein the electronic control (30) is configured to perform speed control and / or torque control of the at least one first electric machine (2) and / or the at least one first hydraulic machine (12); wherein in particular the at least one first electric machine (2) or its inverter (3) and the at least one first hydraulic machine (12) are controlled in such a way that a speed setting and / or an acceleration setting for the vehicle is achieved. [13] Drive system according to one of claims 11 or 12, wherein the electronic control (30) is configured to implement a first drive mode and a second drive mode; wherein in the first drive mode the at least one first electric machine (2) is controlled so that the at least one first wheel (4) is driven, and the at least one first hydraulic machine (12) and / or the second hydraulic machine (16) is / are controlled so that the at least one second wheel (14) is not driven; and wherein in the second drive mode the at least one first electric machine (2) is controlled so that the at least one first wheel (4) is driven, and the at least one first hydraulic machine (12) and / or the second hydraulic machine (16) is / are controlled so that the at least one second wheel (14) is driven. [14] Drive system according to claim 13, wherein the electronic control (30) is configured to perform transitions between the first and the second drive mode in response to operator input and / or automatically.

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