Mobile crane drive unit

Abstract

To provide an improved hybrid drive unit for a mobile crane having as few components as possible and providing many desirable features.SOLUTION: A drive unit for a mobile crane comprises an internal combustion engine 8 for outputting power, an electric machine 22 for outputting power in motor mode and / or generating power in generator mode, and a transfer case 14 for selectively distributing the power output to the transfer case 14 to a drive mechanism and a pumping device 15 for operating the crane. The internal combustion engine 8 cooperates with an input shaft of the transfer case 14. The input shaft cooperates with the drive mechanism. The electric machine 22 cooperates with an intermediate shaft of the transfer case 14. The pumping device 15 cooperates with an output shaft of the transfer case 14.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a drive device for a mobile crane. [Background technology]

[0002] Mobile cranes differ from other types of cranes in that they have their own drive mechanism for moving the crane, allowing for greater flexibility in where they can be used. A typical mobile crane consists of a transport vehicle and a crane attached to it. The transport vehicle is generally either a type of large truck (lorry) chassis or a specially constructed vehicle chassis that is connected to a rotatably mounted crane via a slewing ring.

[0003] As drive systems become more electrified, it is now possible to use electric motors to drive mobile cranes in particular, for example to operate hydraulic pumps required for crane operation, but the prior art continues to rely on internal combustion engines to propel mobile cranes. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide an improved hybrid drive for a mobile crane which requires as few components as possible while providing many desirable functions from those components. [Means for solving the problem]

[0005] This object is achieved by a drive for a mobile crane as specified in independent claim 1. Advantageous embodiments of the drive can be found in the dependent claims. Furthermore, the invention also comprises an advantageous method for operating this drive, which is particularly advantageous for driving the mobile crane on its travel or for reducing exhaust gas emissions.

[0006] According to the present invention, there is provided a drive device for a mobile crane, comprising: an internal combustion engine, particularly a diesel engine, that outputs power; an electric machine that outputs power in its motor mode and / or generates electric power in its generator mode; and a transfer case that selectively distributes the power output to the transfer case to a drive mechanism for moving the mobile crane and a pump device for operating the crane, wherein the internal combustion engine cooperates with an input shaft of the transfer case, the input shaft cooperates with the drive mechanism, the electric machine cooperates with an intermediate shaft of the transfer case, and the pump device cooperates with an output shaft of the transfer case. The drive device is characterized in that a first clutch is arranged between the input shaft and the intermediate shaft for connecting or disconnecting the input shaft and the intermediate shaft as needed, and a second clutch is arranged between the intermediate shaft and the output shaft for connecting or disconnecting the intermediate shaft and the output shaft as needed.

[0007] An advantage of the drive arrangement according to the invention is that the transfer case has an output shaft that can be driven by both the internal combustion engine and the electric machine when the first and second clutches are in their corresponding positions. For example, if it is desired to operate a crane purely electrically, the first clutch can be opened and the second clutch closed, allowing the electric machine to drive the intermediate shaft, and the transfer case output shaft can be operated (by operating the pump) via the closed second clutch, allowing the crane to be operated.

[0008] In this way, the transfer case is configured so that both the internal combustion engine and the electric machine can power the transfer case, which can then transmit this power to the drive mechanism and the pumping device. Thus, when the first clutch (K1) is open, the electric machine can simultaneously power the pumping device via the transfer case, and the internal combustion engine can power the drive mechanism via the transfer case for moving the mobile crane.

[0009] In this regard, the drive system for the mobile crane of the present invention has a redundant configuration for driving the output shaft, since the internal combustion engine can be used as an alternative means in the event of a failure of the electric machine that drives the output shaft (which uses the hydraulic pump to operate the crane). When the first clutch is closed and the second clutch is closed, a frictional connection is created between the input shaft and the output shaft of the transfer case, so the internal combustion engine can also be used to drive the output shaft. This means that even if there is a problem with the electric machine, the crane can continue to operate without coming to a stop.

[0010] A further advantage of the drive system according to the invention is that when the output shaft of the transfer case is driven by the internal combustion engine, the electric machine can also be operated in generator mode, thereby powering auxiliary consumers.

[0011] Thus, the separate alternator common in prior art implementations can be omitted.

[0012] The present invention allows for the use of an internal combustion engine to drive the input shaft of a transfer case. The internal combustion engine may be coupled to the input shaft to drive the input shaft of the transfer case.

[0013] Furthermore, the present invention allows an electric machine to be used to drive or be driven by a transfer case intermediate shaft, and the electric machine can be coupled to the transfer case intermediate shaft to drive it.

[0014] According to yet another advantageous variant, the output shaft of the transfer case is used to drive a pump, in particular a hydraulic pump, of the crane for conveying hydraulic fluid used to carry out the functions of the crane.

[0015] According to an advantageous variant of the invention, the drive device can further comprise energy storage means (power storage means) connected to the electric machine for storing energy (electric power) from the electric machine in generator mode or for supplying energy to the electric machine in motor mode. The energy storage is thus used to receive the power generated by the electric machine or to power the electric machine when it is operated in motor mode.

[0016] Furthermore, the power stored in the energy storage can also be used to supply energy to auxiliary consumers.

[0017] According to an optional embodiment of the invention, it is also possible to charge the energy storage means by means of the charging port from an external power source. When the electric machine is operated in motor mode, the energy supplied via the charging connection can also be used to operate the electric machine in motor mode, in which case charging of the energy storage means no longer takes place or only at a low speed.

[0018] According to an alternative embodiment of the invention, the drive device further comprises at least one auxiliary consumer, in particular a heating element for thermostating the cabin and / or the driver's cab of the mobile crane and / or a compressor of an air conditioning system for thermostating the cabin of the mobile crane and / or a heat pump for thermostating the energy storage device and / or a heating element for thermostating the energy storage device, preferably wherein the at least one auxiliary consumer for energy supply is connected to the electric machine in an intermediate circuit.

[0019] In this regard, at least one auxiliary consumer can be connected to the electric machine so that the electric machine supplies the at least one auxiliary consumer in generator mode. For example, the at least one auxiliary consumer, preferably together with an energy storage device, can be arranged in an intermediate circuit, in particular in a DC intermediate circuit, which is supplied with energy generated by the electric machine. Power supply from energy storage is also possible.

[0020] An advantage of embodiments according to the invention is that the electric machine can be used to drive the hydraulic pump during operation of the electric crane and to power at least one auxiliary consumer during operation with the internal combustion engine, both during crane operation and during travel of the mobile crane. This means that the 24V alternator normally associated with the internal combustion engine can be omitted, as only one electric machine is required. In electric crane operation, the electric machine acts as a motor to drive the crane components, while when powered by the internal combustion engine for travel and / or crane operation, the electric machine is used as a generator.

[0021] Conventional heaters utilize waste heat from the internal combustion engine or rely on fuel-powered auxiliary heaters. However, the present invention allows the compressor of the heating unit or cooling circuit to be operated with energy from an intermediate circuit, an electric machine, or an energy storage unit, making it possible to provide air conditioning independently of the operation of the internal combustion engine or fuel consumption.

[0022] According to yet another alternative embodiment of the present invention, the intermediate circuit can be connectable to an external power source. This allows not only the charging of the energy store but also the continuous operation of the electric machine in motor mode for crane operation. For example, when using a mobile crane, it may be desirable to operate the crane without using the internal combustion engine after the crane has been moved to the work site, so as to avoid exhaust and noise emissions. For this purpose, an external power source is connected and the energy required for operating the crane is derived from the external power source.

[0023] According to a further advantageous embodiment of the invention, the intermediate circuit can be connected to the electric machine via at least one contactor and / or inverter, so that the electric machine can be disconnected from the inverter and the intermediate circuit, which is advantageous, for example, in the event of an inverter failure during drive operation.

[0024] Furthermore, the invention provides that an on-board network, in particular a 12V or 24V on-board network, is connected to the intermediate circuit via a DC / DC converter.

[0025] According to the invention it is further possible for the intermediate circuit to have a voltage level of more than 48V, preferably at least 200V, more preferably at least 500V, most preferably at least 700V.

[0026] According to the invention, the drive device may further comprise a manual transmission for shifting between different gears, arranged between the input shaft of the transfer case and the engine output shaft of the internal combustion engine, the output of the manual transmission cooperating with or being the input shaft of the transfer case.

[0027] To move the mobile crane, it is advantageous for the internal combustion engine to be able to transmit different ratios to the input shaft of the transfer case via a manual transmission. The drive system of the present invention reduces the associated traction interruptions during shifting of the various gears of the manual transmission by closing the first clutch. This prevents a complete loss of traction during gear changes, as the electric machine attached to the intermediate shaft temporarily operates in motor mode. Uninterrupted or reduced interruptions in traction provide a more comfortable driving experience for the mobile crane operator.

[0028] According to an optional embodiment of the invention, the electric machine may be a high voltage electric motor, preferably having an output voltage of at least 400V.

[0029] In accordance with an optional modification of the present invention, when the first clutch is closed and the second clutch is open, the transfer case can be configured to provide power from the internal combustion engine to a drive mechanism (e.g., an axle) that can be used to move the mobile crane. A third clutch can be provided to transmit power input by the internal combustion engine to the input shaft to a drive mechanism, e.g., a driving axle connected to wheels, and the third clutch selectively establishes or releases a press-fit connection between the input shaft and the drive mechanism, particularly the input shaft and the driving axle. In this regard, the third clutch can be disposed within the transfer case.

[0030] Furthermore, according to an advantageous variant, when the first clutch is closed and the second clutch is open, the transfer case is configured to be in a press-fit connection with the electric machine so that the electric machine can generate power in generator mode or supplement the power of the internal combustion engine in motor mode. In this regard, the electric machine can also be solely responsible for driving the mobile crane in its motor mode, i.e. ensure operation of the mobile crane without the assistance of the internal combustion engine.

[0031] According to a further embodiment of the invention, when the second clutch is closed, the transfer case may be configured to decouple the drive mechanism from the input shaft by a third clutch so that crane operation is possible only when the mobile crane is stationary.

[0032] Furthermore, the present invention relates to a mobile crane equipped with a drive device according to one of the above-mentioned aspects, the mobile crane being preferably a large mobile crane having a lifting moment of at least 400 kNm.

[0033] The present invention also relates to a method for operating a drive device according to one of the above aspects or a method for operating a mobile crane according to the above aspects.

[0034] In this regard, the electric machine may be operated during shifting of the manual transmission to reduce drive interruptions caused by the shifting.

[0035] Therefore, during a manual transmission shift to change the ratio of the internal combustion engine, the internal combustion engine drives the input shaft of the transfer case at that ratio, and driving power is supplied by the electric machine, thereby reducing or completely eliminating interruptions in driving power that occur during gear changes.

[0036] Furthermore, according to the invention, during the idling phase of the crane operation, the internal combustion engine can be loaded with an electric machine in generator mode in order to maintain the exhaust gas temperature at a predetermined level, preferably for efficient exhaust gas aftertreatment, and / or to shut down the internal combustion engine after full charging or when the energy storage device has reached a desired state of charge, and continue the crane operation with the energy storage device in order to stop noise or exhaust gas emissions occurring during operation of the internal combustion engine. The internal combustion engine is restarted when the charge level of the energy storage device falls below a predetermined level.

[0037] Further features, details and advantages of the present invention will become apparent from the following description of the figures. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a side view of a mobile crane. [Figure 2] FIG. 2 is a schematic diagram of a drive unit for a mobile crane according to the prior art. [Figure 3] FIG. 3 shows a drive for a crane according to the invention. [Figure 4] FIG. 4 is a schematic diagram showing the connection of the electric machine 22 in a drive arrangement according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] FIG. 1 is a side view of a mobile crane.

[0040] Mobile crane 1 has a lower truck 2 and an upper work 3. The lower truck 2 is provided with a driver's cab 4, and the upper work 3 is provided with a cabin 5. The lower truck 2 is provided with a driving axle 6 having wheels 7. The crane 1 has a jib (also called a crane arm) that is extendable and rotatably hinged to the lower truck.

[0041] FIG. 2 is a schematic diagram of a drive for a mobile crane 1 known from the prior art.

[0042] An internal combustion engine 8, in particular a diesel engine, arranged in the undercarriage 2 drives a driving axle 6 via a powershift transmission 9 and thus the wheels 7. The internal combustion engine 8 is started by a starter 10. The starter 10 receives energy (electricity) from a typical vehicle battery 11 with a voltage of 12 V or 24 V (connection not shown) via an on-board network 12. An alternator 13 is driven by the internal combustion engine 8 and feeds the on-board network 12 to charge the vehicle battery 11. Such an arrangement represents a known system in a vehicle.

[0043] The on-board network 12 supplies energy to all crane components associated with the control system, meaning that the power required by most of the components does not have to be supplied by the vehicle battery 11, as the energy required for this is provided by the internal combustion engine 8. The vehicle battery only supplies the energy required for the electronic control of the components.

[0044] A clutch (not shown) is provided between the power shift transmission 9 and the transfer case 14 to prevent the crane boom from moving while the mobile crane is traveling, and to prevent energy (power) from being transmitted to the transfer case 14 while the mobile crane is traveling.

[0045] During operation of the crane, the internal combustion engine 8 drives the crane's working components (and therefore also at least one hydraulic pump 15). According to the illustrated diagram, power is transmitted via a mechanical connection to the at least one hydraulic pump 15 through the powershift transmission 9 and the transfer case 14. Hydraulic lines to the crane actuators are not shown. The at least one hydraulic pump 15 receives the power required for its control from the on-board network 12, which can be implemented by different types of pumps, for example a swivel pump.

[0046] If emission-free operation is desired, the mobile crane 1 can also use an external power supply 16 as its main power supply (main energy source). Typically, this external power supply 16 can be plugged into the mobile crane 1. A rectifier 18 feeds a DC intermediate circuit 19 via a contactor 17. All crane parts with high energy requirements are connected to this DC intermediate circuit 19. The DC intermediate circuit 19 is present, for example, in the undercarriage 2 and in the superstructure 3. This DC intermediate circuit 19 is established via a slewing ring between the undercarriage 2 and the superstructure 3.

[0047] The cabin 5 is temperature-controlled by a high-voltage heating system 20 and a high-voltage air conditioning compressor. In the prior art, these components are controlled electrically by the on-board network 12. A high-voltage electric motor 22 is connected to and powered by a DC intermediate circuit 19 via an inverter 23. In emission-free crane operation, the powershift transmission 9 is decoupled from the transfer case 14, and all energy from the high-voltage electric motor 22 passes through the mechanical connection and the transfer case 14 to the hydraulic pump 15, so that the energy does not take undesired paths to the powershift transmission. In this operating state (emission-free operation), the internal combustion engine 8 is not running and is therefore unable to drive the alternator 13 and therefore unable to power the on-board network 12. This is carried out by a DC / DC controller 24, which converts the energy provided by an external source so that it can be supplied to the on-board network at the appropriate voltage.

[0048] The power requirements of the on-board network are quite high, around 1 kW, so that without this powering of the on-board network via an external power source the relatively small vehicle battery 11 would quickly discharge.

[0049] A disadvantage of this configuration is that there is no DC intermediate circuit 19 that can be established when operating the crane with the internal combustion engine 8, which supplies energy to, for example, a high-voltage heating system or an HV (high-voltage) air-conditioning compressor. In this case, a generator 25 is clearly required, which must generate a voltage in the high-voltage range, unlike the alternator already present. If it is also desired to heat the cabin 5 by means of a high-voltage heater 20 and a high-voltage air-conditioning compressor 21 during operation of the crane with the internal combustion engine 8, an additional high-voltage generator 25 must also be provided on the internal combustion engine 8 (as shown in Figure 1) to supply energy to these auxiliary consumers. This is also connected to the rectifier 18 via a contactor 17 and has sufficient power to cover the (relatively low) energy requirements of the DC intermediate circuit 19. The high-voltage electric motor 22 is ultimately decoupled and not operated during operation of the crane with the internal combustion engine.

[0050] FIG. 3 shows a drive for a crane according to the invention.

[0051] Unlike the prior art, the electric machine 22 is integrated in a very special way into the transfer case 14 of the drive of the mobile crane 1. One can see an internal combustion engine 8, implemented as a diesel engine, and a manual transmission 9 attached to it. In this respect, the output shaft of the manual transmission 9 acts on an input shaft of the transfer case 14, which can drive the wheel drives 7 of the mobile crane. In this respect, the input shaft can be connected to an intermediate shaft via a first clutch K1, to which the electric machine 22 is connected. The intermediate shaft can be connected to an output shaft of the transfer case 14 via a second clutch K2. This output shaft powers at least one pump required for operating the crane.

[0052] In this regard, FIG. 4 shows which components are connected to an electric machine 22 according to the present invention.

[0053] In this respect, the electric machine 22 is connected via a contactor 28 and an inverter 23 to a DC intermediate circuit 19, from which a number of auxiliary consumers are connected and from which they draw energy.

[0054] An energy storage device 26 can be seen configured to store energy generated by the electric machine 22 when the electric machine 22 is operating in generator mode, or the energy stored in the energy storage device 26 can be used to drive the electric machine 22 in motor mode.

[0055] It can also be seen that a high voltage air conditioning compressor 21 and heater 20 are provided to temperature regulate the cabin of the mobile crane and draw their energy from the intermediate circuit 19.

[0056] The on-board network 12, which typically operates at 12 V or 24 V, is also connected to the intermediate circuit 19 via a DC / DC controller 24. A heat pump 101 and a further heating element 102 may also be provided and used to temperature-regulate the energy storage device 26. Those skilled in the art know that large-capacity energy storage devices are sensitive to their temperature, and it is advantageous to keep them within a preferred temperature range for improved performance and the longest possible service life. This is particularly true during charging of the energy storage unit, since energy can only be stored quickly and gently in the temperature range corresponding to the battery 26.

[0057] Furthermore, an external power source 16 can be seen, which can charge an energy storage device 26 by means of at least one rechargeable battery charger. However, the energy provided by the external power source 16 can also be used directly to drive the electric machine 22. To control the energy flow in the intermediate circuit 19, an optional distribution box 29 can be provided, which includes fuses and corresponding connections. At least one contactor can be provided in such optional distribution box 29 for connection to a rechargeable battery charger. Each device can be connected to the DC intermediate circuit 19 and can draw power from it. The optional distribution box 29 is not present here.

[0058] As can be seen from the combination of Figures 3 and 4, the electric machine 22 can be connected to the drive train of the internal combustion engine 8 by closing the clutch K1. When the mobile crane 1 is moving, the electric machine 22 can assist the internal combustion engine 8 during travel or can provide the entire propulsion power for the mobile crane.

[0059] Furthermore, in driving mode, the electric machine 22 can also be connected to the internal combustion engine via the first clutch K1 and function as a generator. In this way, any auxiliary consumers (e.g. for the battery air conditioning 101, 102, the high-voltage heater 20, the high-voltage air conditioning compressor) can be powered and / or an energy store in the form of the high-voltage air conditioning battery 26 can be charged. This is done via the DC intermediate circuit 19, and in such a state the clutch K2 is normally open.

[0060] Charging by the electric machine 22 is also possible in the internal combustion engine driving mode, and the energy storage device 26 is charged by the electric machine 22 in generator mode.

[0061] When the crane is in operation, the clutch K2 is always closed, since this is the only way to transfer the corresponding energy to the at least one crane pump 15. By activating the first clutch K1, the crane can be operated either internal combustion 8 (clutch K1 closed) or electrically (clutch K1 open).

[0062] When the first clutch K1 is closed, the crane is operated using the internal combustion engine 8 and the electric machine 22 functions as a generator. The energy produced by the electric machine 22 is used to power auxiliary consumers or to charge the energy store 26. The effect of this is that no additional heating or additional mechanical air conditioning compressors are required, since the respective components can be operated using the DC intermediate circuit 19 and the electric machine 22 in generator mode.

[0063] When the crane is in operation, the cabin 5 is always air-conditioned via the high-voltage components (high-voltage heater 20 and high-voltage air-conditioning compressor), regardless of whether the crane is operated using the internal combustion engine or the electric machine 22. This has the advantage that air-conditioning is possible even when the output shaft 27 is stationary and no fuel combustion is desired.

[0064] When the electric crane is in operation, ie when the internal combustion engine 8 is not running, energy for the auxiliary consumers is supplied from the energy store 26 or from the external power source 16 .

[0065] The advantage of this is that the high voltage air conditioning compressor 21 and high voltage heater 20 can also provide air conditioning for the cabin 5 even when the entire drivetrain (engine, transmission, axles) is stopped, and furthermore, no pollutants are emitted when the high voltage air conditioning compressor 20 is operating compared to a fuel-powered parking heater.

[0066] An effective way to operate the drive is to keep the internal combustion engine 8 loaded in order to keep the exhaust gas temperature above a certain temperature threshold, and to utilize the idling phase of crane operation, i.e., the phase when the crane is not moving. This improves exhaust gas aftertreatment and leads to an overall reduction in emissions. When the energy storage unit 26 is fully charged or has exceeded a certain charge level, the internal combustion engine 8 can be stopped and the crane operation can continue using the electric machine 22 coupled to the energy storage unit. Stopping the internal combustion engine 8 also stops the noise emitted by the internal combustion engine and reduces idling of the internal combustion engine 8.

[0067] Furthermore, the drive arrangement can be advantageously used to mitigate or completely eliminate the interruption of drive power of a manual transmission of an internal combustion engine that occurs during gear shifting. The power flow from the internal combustion engine 8 to the wheels 7 must be temporarily interrupted for a gear shift, but this interruption is mitigated by applying a corresponding force by the electric machine 22 in motor mode.

[0068] Another advantage is that in the event of a failure of the electric machine 22, the crane is still able to operate using the internal combustion engine and the corresponding mechanical shaft (when the first clutch K1 and the second clutch K2 are closed), so that all functions of the crane are maintained even in the event of a malfunction in the high-voltage system. This is not necessarily the case when a high-voltage electric motor is used for the diesel engine and an electric motor is used to drive the hydraulic pump, since there is no need to mechanically connect the internal combustion engine 8 to the hydraulic pump. [Explanation of symbols]

[0069] 1. Mobile crane 2 Lower bogie 3 Superstructure 4. Driver's cab 5 Cabins 6 Driving Axle 7 wheels 8. Internal combustion engine 9 Powershift Transmission 10 Starter 11 Vehicle Battery 12 In-vehicle network 13 Alternator 14 Transfer case 15 Hydraulic pump 16 External power supply 17 Contactor 18 Rectifier 19 DC intermediate circuit 20 High Voltage Heater 21 High voltage air conditioning compressor 22 High voltage electric motor 23 Inverter 24 DC / DC controllers 25 High-voltage generator 26 High Voltage Battery 27 axes 28 AC Contactor 29 High Voltage Distribution Box K1 clutch K2 clutch 100 steering pump 101 Heat Pump 102 High voltage heater

Claims

1. A drive device for a mobile crane, comprising: an internal combustion engine for outputting power; an electric machine that outputs power in a motor mode and / or generates energy in a generator mode; a transfer case that selectively distributes power output to the transfer case to a drive mechanism for moving the mobile crane and a pump device for operating the crane; the internal combustion engine cooperates with an input shaft of the transfer case; the input shaft cooperates with the drive mechanism; the electric machine cooperates with a transfer case intermediate shaft; the pumping device cooperates with the transfer case output shaft; a first clutch is disposed between the input shaft and the intermediate shaft for connecting or disconnecting the input shaft and the intermediate shaft to each other as needed; a second clutch is disposed between the intermediate shaft and the output shaft for connecting or disconnecting the intermediate shaft and the output shaft to each other as needed; A drive system further comprising a manual transmission for shifting between different gears, the manual transmission being arranged between an input shaft of the transfer case and an engine output shaft of the internal combustion engine, the output of the manual transmission cooperating with or being the input shaft of the transfer case.

2. 2. The drive device according to claim 1, The drive system further comprising an energy storage device connected to the electric machine for storing energy from the electric machine in generator mode or for supplying energy to the electric machine in motor mode.

3. 2. The drive device according to claim 1, A drive unit further comprising at least one auxiliary consumer, the at least one auxiliary consumer being connected to the electric machine in an intermediate circuit for energy supply.

4. 4. The drive device according to claim 3, A drive device in which the intermediate circuit is connectable to an external power source.

5. 4. The drive device according to claim 3, A drive arrangement in which the intermediate circuit is connected to the electric machine via at least one contactor and / or inverter.

6. 4. The drive device according to claim 3, A drive in which an on-board network is connected to the intermediate circuit via a DC / DC converter.

7. 2. The drive device according to claim 1, A drive arrangement in which the electric machine is a high voltage electric motor.

8. 2. The drive device according to claim 1, The transfer case is configured to provide power from the internal combustion engine to the drive mechanism usable to move the mobile crane when the first clutch is closed and the second clutch is open.

9. 9. The drive device according to claim 8, The transfer case is configured to establish a press-fit connection with the electric machine when the first clutch is closed and the second clutch is open, such that the electric machine can generate electrical power in a generator mode or supplement the power output of the internal combustion engine in a motor mode.

10. 2. The drive device according to claim 1, The transfer case is configured to disconnect the drive mechanism from the input shaft by a third clutch when the second clutch is closed so that crane operation is possible only when the mobile crane is stationary.

11. A mobile crane equipped with the drive device according to any one of claims 1 to 10, A mobile crane characterized in that it is a large mobile crane having a lifting moment of at least 400 kNm.

12. 10. A method of operating the drive device of claim 1.

13. 13. The method of claim 12, the drive device further comprises a manual transmission for shifting between different gears, the manual transmission being arranged between an input shaft of the transfer case and an engine output shaft of the internal combustion engine, the output of the manual transmission cooperating with or being the input shaft of the transfer case; 10. A method comprising: motoring the electric machine during shifting of a manual transmission to mitigate drive power interruptions caused by the shifting operation.

14. 13. The method of claim 12, 1. A method for operating a crane, comprising: loading the internal combustion engine with the electric machine in generator mode during an idling phase of the crane operation in order to maintain the exhaust gas temperature at a predetermined level, to perform exhaust gas aftertreatment with high efficiency, and / or to stop the internal combustion engine after full charging or when the energy storage has reached a desired state of charge, and to continue the crane operation with an energy storage device in order to stop noise or exhaust gas emissions occurring during operation of the internal combustion engine.

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