DE19952625A1 - Drive system - Google Patents

Abstract

A drive system comprises an electric machine (12) and an output member (52) which can be coupled or coupled to a drive shaft (18) of a drive unit (16) for rotation, by means of which electric machine (12) the drive shaft (18) can be driven for rotation or / and electrical energy can be obtained from the rotation of the drive shaft (18), the electrical machine (12) comprising a stator arrangement (30). The system has a rotor arrangement (20) connected or connectable to the output member (52) via a gear arrangement (14) with a variable speed conversion ratio for rotation and a first clutch grounding (56) through which a torque transmission connection between the rotor arrangement (20) and the output member (52) can be produced.

Description

The present invention relates to a drive system comprising a Electric machine and one with a drive shaft of a drive unit output element which can be coupled or coupled by means of which the electric machine can drive the drive shaft for rotation or / and electrical energy can be obtained when the drive shaft rotates, the Electric machine comprises a stator arrangement.

From WO 98/40647 a drive system is known in which an internal combustion engine via a clutch and a transmission a drive moment can be directed to drive wheels. It is also a Electric machine provided by which the internal combustion engine can be started and by which when the internal combustion engine rotates Electrical energy can be generated. The electric machine is in the transmission integrated or torque transmission to the Gearbox coupled, with an output member of the electric machine through different speed conversion stages of the transmission in terms of Torque transmission ratios changeable with the drive unit can be coupled. This build one Drive system is relatively complex and in particular requires one massive modification of conventional gears, because in the area of the gears the interaction between the electric machine and the Drive unit must be provided.

It is the object of the present invention to provide a drive system to provide, in which without significant structural change from other components of a drive train in a simple manner one with regard to its torque transmission coupling to a Drive unit changeable electric machine can be provided.

According to the invention, this object is achieved by a drive system, comprising an electric machine and one with a drive shaft Drive unit for rotating coupled or coupled output link through which the electric machine rotates the drive shaft is drivable and / or electrical energy when the drive shaft rotates is obtainable, the electric machine comprising a stator arrangement.

The system according to the invention has one with the output member a gear arrangement with variable speed conversion ratio Rotation connected or connectable rotor assembly and a first Coupling arrangement through which a torque transmission connection between the rotor assembly and the output member can be produced.

The electric machine is therefore in the drive system according to the invention designed such that ultimately to change the torque transmission ratio used already with the Electric machine is combined into a functional unit, d. H. in the Area of action between the rotor assembly and the output member the same lies. Ultimately, this means that a closed entity is formed, in which speed control by appropriate control Implementation ratios can be changed. A constructive one Redesign in the area of normal vehicle transmission is not required. Furthermore, the drive system according to the invention is in particular with regard to the relative positioning of the electric machine with respect to the  Drive unit significantly less limited than that from the stand Systems known in the art since, as mentioned above, the Electric machine with the gearbox assigned to it an independent Unit forms and for example also on the power take-off side of the Drive unit can be provided.

A particularly simple structure in which the control effort for Switching between different speed conversion ratios can be minimized can be obtained by the first clutch assembly comprises a freewheel arrangement through which a torque in essentially only transferable from the output member to the rotor arrangement is.

In particular in the start-up mode, i.e. in the starter mode, the Starting internal combustion engines with larger displacement required To get torque, it is suggested that the gear assembly has at least one selectively activatable gear conversion stage at which, when activated, has a speed ratio speed the rotor arrangement / speed of the output member is greater than 1.

Furthermore, it can be provided that in the non-activated state of the at least one transmission conversion stage with a speed ratio different from 1 for torque-transmitting first clutch arrangement, the speed ratio is 1 .

To the torques that occur during starting in a suitable manner To be able to support, it is proposed that the at least one Gear conversion stage with a speed ratio different from 1 by selectively activating a reaction torque support arrangement can be activated. It is preferably provided that the reaction Torque support arrangement a preferably electromagnetic  can be activated and / or deactivated and preferably positively or / and includes a frictionally acting second clutch arrangement.

A very space-saving design, which is still for transmission very high torques without the risk of excessive Wear is suitable can be obtained that the Gear arrangement comprises a planetary gear, which one with the Rotor arrangement connected sun gear, a ring gear, which optionally can be fixed against rotation or is released for rotation, and at least one rotatably carried on a planet carrier Planet gear, which with the sun gear and the ring gear in Torque transmission connection is, the planet carrier forms or is connected to the output member.

Here it is advantageous if the ring gear by the reaction moments support arrangement can be fixed against rotation.

To be in rotary operation, either in starting operation or a generator Operation or a torque assist operation to ensure that occurring rotational irregularities, either in the area of Drive unit or in the area of the electric machine, not or will only be transferred to the other unit to a lesser extent struck that an interaction area of the rotor assembly over a torsional vibration damper assembly in connection with the Sun gear stands.

The drive system according to the invention is preferably constructed in such a way that the rotor arrangement radially surrounds the stator arrangement.

According to a further advantageous independent aspect of the above lying invention can be characterized in that the stator arrangement  Stator carrier includes one in a radially outer area Interaction area of the stator arrangement carries, and the at least surrounds part of a gear arrangement radially on the outside, for a very space-saving design.

This design, in which the stator carrier is staggered radially between the interaction area of the stator arrangement and at least part of the gear arrangement can be simultaneously a cooling arrangement through which the interaction area of the Stator arrangement and the gear arrangement can be cooled for this be taken care of these two functional groups Interaction area of the stator arrangement and gear arrangement be cooled by a common cooling arrangement. It can for example, it can be provided that the cooling arrangement contains a coolant includes channel arrangement in the stator, the coolant channel arrangement can be brought in connection with a coolant source or is.

As already mentioned above, by designing the drive system according to the invention with the gear arrangement summarized electrical machine positioning for example the power take-off side of the drive unit while maintaining the possibility ability to change the torque transmission ratio created.

Furthermore, by using the gear arrangement in the area between the rotor assembly and the output member of the electric machine Possibility created that when coupled to the drive shaft Output member, the rotor assembly to the drive shaft arranged coaxially is. This also contributes to a very small size.

Furthermore, it is advantageous if the electric machine is preferably in the Area of a stator support via an elastic connection arrangement  a fixed assembly, preferably the drive unit, is connected or connectable. This way will continue avoided vibrations occurring during operation or Wobble in the area of the drive shaft due to a very rigid Coupling of the system according to the invention to a fixed one Assembly in the range of bearing arrangements of the different movable components can damage them.

In a drive system as described above, at which in the torque transmission path between the rotor assembly the electric machine and a drive shaft by changing the speed Implementation ratio an adaptation to different operating conditions can be made, there is a fundamental risk that at this change in the speed conversion ratio switching shocks occur. To avoid this, there are several known in the art clutches used to carry out the switching operations at the Execution of the switching operations to let grind, but what a leads to considerable wear.

It is therefore further proposed according to the present invention a method for controlling a drive system, the drive system having an electric machine and an output member coupled to a drive shaft of a drive unit for rotation, the drive shaft being drivable for rotation by the electric machine and / or upon rotation of the Drive shaft electrical energy can be obtained, the electric machine further comprising a stator arrangement and a rotor arrangement connected or connectable to the output member via a transmission arrangement with a variable speed conversion ratio for rotation, the transmission arrangement comprising at least two transmission conversion stages with a different speed ratio speed of the rotor arrangement / speed of the Output member, wherein the method for performing a switching process from an established gear conversion stage to a gear conversion stage to be set up comprises the following steps:

• a) Determine the speed of the drive shaft and / or determine the Speed of rotor assembly,
• b) when the speed of the drive shaft or the speed of the Rotor arrangement reaches a predetermined limit speed, Change one between the rotor assembly and the Output member transmitted torque to a Ent coupling value,
• c) if that between the rotor assembly and the output transmitted torque in the range of the decoupling value is interrupting the torque transmission connection between the output member and the rotor assembly,
• d) changing the speed of the rotor assembly in the direction of one of the set target gear set to be set up Rotor speed too,
• e) when the speed of the rotor arrangement in the range of the target Rotor speed is, producing the torque transfer supply connection between the output member and the Rotor arrangement to maintain the gear to be set up Implementation stage.

With such a method it is achieved that through the introduction or adjusting the speeds of the interacting Assemblies with a positive fit even when used, for example Coupling arrangements to avoid the occurrence of switching shocks can, so that on the one hand the driving comfort is increased and on the other hand the Reduced loads occurring in the area of the drive system become.  

For example, it can be provided that the target rotor speed is a Speed is obtained by multiplying the speed of the drive shaft by the speed ratio of the gearbox conversion stage to be set up becomes.

Because when adjusting the speeds of the interacting with each other Assemblies even if there is a speed match switching shocks can occur, namely when the speed Changes in these two assemblies are very different further proposed according to the invention that step e) a step e ') includes, in which when the speed of the rotor assembly in the Range of the target rotor speed is a change in speed of the rotor arrangement voltage is adapted to a change in speed of the drive shaft, wherein the torque transmission connection between the rotor assembly and the output member is then produced when the speed Change in the rotor arrangement to the change in speed of the drive shaft is adjusted. It is then advantageous if step e ') only then is carried out when the speed change of the drive shaft is higher as a threshold speed change.

There can be a freewheel arrangement in at least one gear conversion stage be provided, by which a torque essentially only from the output member can be transmitted to the rotor assembly.

When using such a freewheel arrangement, the Carrying out the method according to the invention insofar as this for example when switching from one gear conversion stage to one other (operations conversion stage with higher speed ratio the step b) a step b ') for generating a drive torque in the Rotor assembly includes the between the rotor assembly and the Output member transmitted torque to a value in the range of 0  than to change the decoupling value, and that in step c) the Interrupting the torque transmission connection occurs independently, when the decoupling value is reached or exceeded.

It is further preferably provided that the speed ratio is 1 in one of the gear conversion stages and that the speed ratio is greater than 1 in at least one of the other gear conversion stages. In this case, the freewheel arrangement is preferably provided in the gear conversion stage whose speed ratio is 1 .

In the method according to the invention it can be provided that the Switching from a gear conversion stage with lower Speed ratio in a gear conversion stage with a higher Speed ratio of step d) generating a drive Torque in the rotor assembly includes. In this case it is advantageous if in step e) when the speed of the Rotor arrangement in the range of the target rotor speed, the generation of Drive torque is ended. Furthermore, that The inventive method can be carried out in such a way that Switching from a gearbox conversion stage with a higher speed ratio in a gear conversion stage with a lower speed ratio of step d) comprises generating a braking torque in the rotor arrangement. Again, it is advantageous if in step e) when the speed the rotor arrangement is in the range of the target rotor speed, the generation of the braking torque is ended.

In particular also when performing a decoupling process, that is when designing or terminating a transmission conversion stage, the occurrence to avoid switching surges, it is proposed that step b) reducing a braking generated in the rotor assembly Torque, preferably to a value in the range of 0, and  if necessary, generating a drive torque at the Includes rotor assembly.

Even with such arrangements, in which through targeted control the transmission arrangement the occurrence of switching shocks is avoided it is advantageous to reduce the number of switching operations to be carried out hold. It is therefore further proposed that in step b) transmitted between the output member and the rotor assembly Torque is only changed if after reaching the Limit speed has passed a predetermined period of time. Temporary Speed changes can not be too fast Carry out switching operations.

Furthermore, in order to avoid unnecessary switching operations, it is advantageous if in step b) that between the output member and the Rotor arrangement transmitted torque is only changed when after reaching the limit, the speed of the drive shaft or the rotor arrangement for a predetermined period of time remains beyond the limit speed.

With a procedure described above, it is possible to to pursue different shaft strategies in order to To be able to use the system in an optimal way. For example it can be provided that the limit speed is determined as a speed, if they are exceeded, the gear conversion stage to be set up the maximum power output of the electrical machine when generating electrical Energy is higher than with the gear conversion stage set up. Alternatively, it is possible that the limit speed for a particular Operating state is determined as a speed when exceeded the efficiency of the gearbox conversion stage to be set up Electric machine when generating electrical energy is higher than that  set up gear conversion stage, for example the Operating state at least by the performance requirement on the Electric machine is determined.

The efficiency of such a procedure or the efficiency of a Such a system can use such switching strategies be optimized in that the limit speed to optimize the maximum power output of the electrical machine when generating electrical Energy is determined when using an electric machine electrical power system has a high performance requirement, preferably in the range of 60% -100% of the maximum power of the Electric machine, is present when generating electrical energy, and that the speed limit to optimize the efficiency of the Electric machine is determined when generating electrical energy if the system performance requirement in the range of less than 60% of the Maximum power of the electric machine when generating electrical energy lies.

A further optimization of the use of a system according to the invention or the procedure according to the invention can thereby be obtained that a gearbox conversion to start the drive unit stage with higher speed ratio, preferably in the range of 4, is set up and that after reaching the limit speed a gearbox Conversion stage with a lower speed ratio, preferably in the range of 1, is set up, whereby it can also be provided here that after Set up the transmission conversion stage with a lower speed ratio Switching the gear conversion stages regardless of the speed of the Drive shaft or the rotor assembly essentially is omitted. This way too, the implementation can be unnecessary Switching operations are avoided.  

For example, it can be provided that switching the transmission Implementation stage essentially does not occur if one Power requirement of one of the electrical machine with electrical System powered in a lower range, preferably less than 30% of the maximum power of the electric machine when it is generated electrical energy.

The procedure according to the invention described above can preferably be carried out with a gear arrangement, the one Includes planetary gear. This planetary gear then points preferably on: a sun gear connected to the rotor arrangement Ring gear, which can be optionally opposed by a clutch arrangement Rotation is fixable, at least one rotatable on a planet carrier supported planet gear, which with the sun gear and the ring gear in Torque transmission connection is, the planet carrier forms or is connected to the output member, and another Coupling arrangement through which a preferably essentially direct torque transmission connection between the planet gear Carrier and the rotor assembly can be produced, wherein for setting up a Gear conversion stage with a higher speed ratio through the ring gear the clutch assembly is held substantially non-rotatably and the further clutch arrangement essentially no torque over bearing connection between the rotor assembly and the planet gear carrier provides, and being used to set up a gear conversion stage lower speed ratio, preferably a speed ratio of 1, the clutch assembly essentially not against the ring gear Specifies rotation and the further clutch arrangement a torque Transmission connection between the planet carrier and the rotor arrangement provides.  

As already explained above, the second can Clutch assembly include a freewheel assembly through which a Torque essentially only from the planet carrier Rotor arrangement is transferable.

The present invention will hereinafter be described with reference to the accompanying Drawings in detail based on preferred embodiments described. It shows:

Fig. 1 is a schematic longitudinal sectional view of an inventive drive system;

FIG. 2 shows a principle axial view of the planetary gear used in the drive system according to FIG. 1;

Fig. 3 is a longitudinal sectional view of an embodiment form of the drive system of the invention;

FIG. 4a) is a time chart of the change in speed of a drive shaft and the speed change of a rotor assembly;

FIG. 4b) a time diagram associated with FIG. 4a) of the torque curve of an electric machine used in the drive system according to the invention;

FIG. 5a) is a time chart of the change in speed of a drive shaft and the speed change of a rotor assembly;

FIG. 5b) a time diagram of the torque curve of an electric machine used in the drive system according to the invention, associated with FIG. 5a);

Figure 6 shows the dependency of the maximum electrical power that can be generated by the electric machine on the speed of a drive shaft and for different conversion ratios of a transmission;

FIG. 7 is a diagram corresponding to FIG. 6, in which lines of constant efficiency for different gear conversion stages are also shown.

First, the structure of an inventive drive system will be described with reference to FIGS. 1-3. As essential functional groups, this drive system 10 comprises an electric machine 12 , a transmission arrangement 14 , these functional groups interacting with a drive unit 16 , which is indicated schematically in FIG. 3, ie its drive shaft 18 , for example the crankshaft of an internal combustion engine.

The electric machine 12 , which in the exemplary embodiment shown is an external rotor machine, comprises a rotor arrangement 20 with a rotor carrier 22 which carries a rotor interaction region 24 in its radially outer region. This can, as shown for example in FIG. 3, comprise a plurality of sheet metal plates or the like 26 which are connected to the rotor carrier 22 on their outside and carry a plurality of permanent magnets 28 on their inside.

The electric machine 12 further comprises a stator arrangement, generally designated 30, with a stator carrier 32 and an interaction region 34 of the stator arrangement 30 carried radially on the outside of the stator carrier. This interaction area can comprise a plurality of coils 36 , which are supplied with energy by a line arrangement 38 in a manner known per se. As shown above, the electric machine 12 is preferably a permanently excited synchronous machine with an external rotor.

The rotor assembly 20 , ie the rotor carrier 22 , can have a torsional vibration damper arrangement 40 , as indicated schematically in FIG. 1, which has a plurality of successive springs or spring arrangements 42 in the circumferential direction, which are supported in the circumferential direction on two parts 44 , 46 of the rotor carrier 22 and thus allow a circumferential relative movement of these two parts 44 , 46 with respect to each other. This configuration, which is advantageous for providing a vibration damping function, is, however, not absolutely necessary, as can be seen in FIG.

The part 46 of the rotor carrier 22 is connected in its radially inner region to a sun gear 48 of the gear arrangement 14 , which thus forms a planetary gear arrangement, in a rotationally fixed manner and is rotatably supported on the stator carrier 32 via a bearing 50 . Furthermore, a planet gear carrier, generally designated 52, is rotatably supported on the part 46 of the rotor carrier 22 via a bearing 54 . Between the part 46 of the rotor carrier 22 and the planet gear carrier 52 , a free-wheel arrangement 56 is also provided, which in one direction of rotation allows the planet gear carrier 52 to rotate essentially freely with respect to the rotor carrier 22 and thus the rotor arrangement 20 , but in the other relative direction of rotation the two parts or Modules rotor assembly 20 and planet carrier 52 rotatably coupled together.

The planet gear carrier 52 is also rotatably supported by a bearing 58 on the stator carrier 32 or a component or assembly firmly connected thereto.

The planet gear carrier 52 carries a plurality of planet gears 60 arranged in succession in the circumferential direction, which mesh radially on the inside with the sun gear 48 and are meshed radially on the outside with a ring gear 62 . The ring gear 62 is arranged essentially floating within the space enclosed by the stator carrier 32 , that is to say can basically rotate freely with respect to the stator carrier 32 . However, a clutch arrangement 64 is provided, by means of which the ring gear 62 can optionally be fixed against rotation when activated. In the embodiment shown, the clutch arrangement 64 is an electromagnetic clutch arrangement with an excitable coil arrangement 66 , to which electrical energy is supplied via a line 68 . When the coil arrangement 66 is excited, the ring gear 62 is axially pulled toward it and then held in a rotationally fixed manner by frictional engagement, for example with the interposition of a friction surface or a friction lining 70 or the like. Here as well a form-fitting engagement assembly to the ring gear 62 and the clutch assembly 64 or a case intended component can be realized, so that in the engaged or activated state of the clutch assembly 64, the ring gear is held by a form fit against rotation 62nd It should also be pointed out that the clutch arrangement can achieve a rotationally fixed mounting of the ring gear 32 , for example by means of hydraulically actuatable stamps or the like.

It can also be seen that the entire assembly, formed from elec tric machine 12 and gear arrangement 14 in the area of the stator carrier 32 in an elastic manner on a fixed assembly, for example the drive unit 16 , is fixed. This can be done via elastically resilient rubber suspension elements, springs or other suspension elements 72 , which allow vibration decoupling of these assemblies 12 , 14 from the drive unit 16 . It can thus be avoided that radial and axial vibrations of the drive shaft or crankshaft 18 are transmitted to these assemblies 12 , 14 to an excessive extent. A friction device can also be assigned to the suspension elements 72 , so that vibrations that occur can not only be absorbed but also their amplitude can be damped.

With reference to FIG. 3, some advantageous constructive details of an embodiment of the drive system 10 according to the invention are described below. It can be seen in Fig. 3 that the stator is composed of several components 32. This comprises a first component 74 , on the outer peripheral region of which a groove-like channel system is formed, which is closed by a ring-like or cylinder-like cover element 76 , on which the coils 36 are ultimately supported. The component 74 extends on the drive unit 16 facing side of the coils 32 radially beyond this to the outside and has in this area a plurality of supply channels 78 which are in communication with the groove-like channels 80 . In this radially outer region, the stator carrier 32 forms an labyrinth seal with an overlapping cylindrical region 84 of the rotor carrier 22 through an axial cylindrical projection 82 , so that the entire system is protected against the ingress of contamination. The rotor carrier 22 has cooling fins 86 in the radially outer region, but can also be designed in this region to drive a belt transmission which drives, for example, the compressor of an air conditioning system or the like. However, this can also be achieved in that a separate pulley is connected to the rotor carrier 22 in a rotationally fixed manner. Furthermore, a sensor arrangement 90 is provided in the radially outer area on the stator carrier 32 , which scans a marking 92 indicated schematically in FIG. 2, for example formed by a plurality of projections or the like on the rotor carrier 22 , and in this way provides information about the Rotational position and the rotational speed of the rotor assembly 20 can generate. The information about the rotational position is particularly necessary for the commutation of the stator coils 36 . Since the rotor carrier 22 closes the overall system radially outward and axially and thus forms a type of housing for it, the provision of an additional housing part can be dispensed with, so that the cooling air flow can better access the drive system according to the invention.

For cooling, a cooling fluid, for example cooling water, is also passed into the stator carrier 32 via the channels 78 and the channel system 80 , so that due to the arrangement of this channel system 78 , 80 in the stator carrier 32 in a region radially between the stator coils 36 and the gearbox arrangement 14 the cooling channel system 78 , 80 can be used to cool these two functional groups. It is not necessary to provide a separate cooling system for the transmission 14 and a separate cooling system for the interaction area 34 of the stator arrangement 30 . The design as an external rotor machine provides an essential aspect for this, so that no assemblies of the rotor arrangement 20 have to lie between the interaction region 34 of the stator arrangement 30 and the gear arrangement 14 .

It should be noted that the channels 78 are connected to a coolant source via a flexible line system in order to enable the elastic suspension of the electric machine 12 described above together with the gear arrangement 14 .

Another component 94 of the stator carrier 32 is firmly connected to the component 74 by means of screw bolts or the like and supports a component 96 which supports or forms the sun gear 48 radially on the inside via the bearing 50 . As can be seen in FIG. 3, this component 96 can be firmly connected to the rotor carrier 22 by means of screw bolts or the like. Between the components 94 and 74 a ring-like blocking element 98 is clamped, which forms an axial movement stop for the ring gear 62 . In the not blocked by the clutch assembly 64 against rotation state thus the ring gear 62 can axially only slightly from the clutch assembly 64, ie, the coil assembly 66, move away.

The planet gear carrier 52 , which is fixedly connected in its central region to the drive shaft or crankshaft 18 via a fastening screw 100 , has a plurality of bearing sections 102 in its radially outer region, on which the planet gears 60 are rotatably supported with respective bearing shafts 104 . On their other axial side, the planet gears are rotatably supported with their bearing shafts 104 in a bearing ring 106 , which is firmly connected to the planet gear carrier 52 in a circumferential region between two planet gears 62 by bolts or the like, and which is also supported by a bearing 108 is rotatably supported on the part 96 which carries or forms the sun gear 48 .

The drive system, as shown in FIGS. 1-3, is designed such that it can preferably be attached to the power take-off side N of the drive unit 16 , ie on the side on which the drive unit 16 is not in rotary drive connection with, for example, a Clutch, a transmission u. Like. Contains drive train. In this way, the space available in a vehicle can be optimally used. In addition, since the essential assemblies electric machine 12 and gear arrangement 14 are positioned coaxially with the axis of rotation A of the entire drive system, ie in particular the drive shaft 18 , connection via a belt transmission or the like can be dispensed with. This also leads to a reduction in the installation space occupied by the system according to the invention and, at the same time, reduces wear to an insignificant extent, since such planetary gears, as shown in FIGS. 1-3, can work essentially without wear and otherwise do not wear out to a great extent Assemblies such as belt gears or the like must be provided.

The mode of operation of the drive system according to the invention is described below in particular with reference to FIG. 2. It is initially assumed that in start-up operation, that is to say in an operation in which the system according to the invention, in particular the electric machine 12 , operates as a starter, by appropriate excitation of the stator coils 36 and the magnetic interaction generated thereby between the magnetic field of the stator coils 36 and the magnetic field the rotor permanent magnet 28, the rotor assembly 20 is rotated in the direction of an arrow P ₁ in Fig. 2. As a result, the sun gear 48 , which is connected to the rotor arrangement 20 in a rotationally fixed manner, also rotates in the same direction, namely the direction of the arrow P ₂ . The planet gears 60 , which mesh with the sun gear 48 , are thereby driven to rotate in the direction of an arrow P ₃ . In this starting state, the ring gear 62 is, for example, held against rotation by energizing the coil arrangement 64 , so that the rotating planet gears 60 cannot lead to the rotation of the ring gear 62 , but rather due to their induced rolling movement in the direction of an arrow P ₄ along the inner circumference of the Ring gear 62 will move. The planet gears 60 take the planet gear carrier 52 in the same direction, so that the drive shaft 18 will also rotate in the same direction as the planet gear carrier 52 and thus also in the same direction as the rotor arrangement 20 . However, the drive shaft 18 rotates at a reduced speed in accordance with the speed conversion ratio of this gear conversion stage, which is activated when the clutch arrangement 64 is energized, ie activated, and the ring gear 62 is thus blocked against rotation. In a preferred embodiment, the speed conversion ratio between the speed of the rotor arrangement 20 and the speed of the planet gear carrier 52 , which here forms an output member of the gear arrangement 14 and thus of the entire system 10 , is in the range of 4. It is thus reduced by the speed achieved a translation of the torque, so that the drive system according to the invention is particularly suitable for starting larger internal combustion engines.

If the internal combustion engine is started, the excitation of the stator coils 36 can be ended and, while the clutch arrangement 64 is still activated, the rotor arrangement is now rotated at a higher speed than the drive shaft 18 via this activated gear conversion stage. The electric machine 12 can now work as a generator, ie it can convert kinetic energy of the rotor arrangement 20 into electrical energy and feed it into an electrical system of a vehicle or an accumulator.

Since such electromechanically operating generators have an efficiency which is dependent on the rotor speed, it may be necessary, however, at higher speeds of the drive shaft 18 to ensure that the relatively high speed conversion ratio of the gear conversion stage which is provided for starting operation and which is set up when the clutch arrangement 64 is activated is abandoned and a lower conversion ratio, for example a conversion ratio of 1, is used. This is achieved automatically when the activation of the clutch arrangement 64 is ended, ie the ring gear 62 is released for rotation. Then no longer takes place in this state in which a torque support of the sun gears 16 via the ring gear 62 on the stator 32, would then be when the rotation speed of the rotor assembly 20 with the rotational speed of the drive shaft 18 coincides or the speed of the drive shaft 18 is higher than the speed of the rotor arrangement 20 , the freewheel 56 is effective in such a way that it now generates a direct rotationally fixed connection between the rotor arrangement 20 , ie the rotor carrier 22 , comprising the part 96 shown in FIG. 3, and the planet gear carrier 52 and thus the drive shaft 18 . In this state, the rotor arrangement 20 now rotates at the same speed as the drive shaft 18 .

Due to the inventive design of the gear arrangement 14 with its two gear conversion stages, one of which provides a speed ratio different from 1 between the speed of the rotor arrangement 20 and the speed of the planet gear carrier 52 acting as an output member, and of which one provides a direct coupling between the rotor arrangement 20 and the drive shaft 18 provides a very simple and efficient structure is created. The speed conversion ratio of 1 is in fact generally only required if a generator operation is to take place and thus a torque is to be transmitted from the drive shaft 18 to the electric machine 12 . In this state, however, the freewheel 56 takes effect automatically unless the clutch arrangement 64 is activated. That is, without activation of the clutch arrangement 64 , no measures are required to provide this torque flow from the drive shaft 18 to the electric machine 12 . In the opposite torque flow direction, however, a transmission ratio of 1 is practically not necessary, since the gear unit conversion stage is preferably used for starting the drive unit 16 , in which the ring gear 62 is held in a rotationally fixed manner by activating the clutch arrangement 64 and thus a torque transmission takes place. The result is that it is possible to switch between different gear conversion stages with minimal control effort, namely only by correspondingly controlling the clutch arrangement 64 . It is thus possible to generate start-up operation, start-up support for the drive unit, generator operation or engine braking operation, and the generation of a support torque with minimal switching effort.

However, it should be noted that, instead of the freewheel 56, of course, a clutch which can be switched by actuation can also be provided, which can be particularly advantageous if the electric machine 12 is to be used, for example, in smaller vehicles as a drive unit or as a supporting drive unit.

In order to avoid the occurrence of shift shocks when performing shifting operations between the two above-described transmission-conversion stages, which may be the case particularly when the clutch assembly 64 defines by positive locking action of the ring gear 62 against rotation, a procedure may be carried out as will be described below with reference to FIGS. 4 and 5. Here, a process, the drive unit is shown in FIG. 4, in which at time 0 started as described in the starter mode as previously to start 16th In this state, the clutch arrangement 64 is activated, the ring gear 62 is fixed against rotation and the gear conversion stage is activated in which a relatively high speed conversion ratio between the rotor speed and the planet carrier speed, for example in the range of 4, is provided. By the time t _1, the idling speed of the drive unit in the range of 500 revolutions per minute has been reached, which can be seen by the curve AA in Fig. 4a), as can be seen in Fig. 4b), a torque is generated by the drive unit. The positive torque range in FIG. 4b) thus means the state in which a drive torque is generated on the rotor arrangement 20 by appropriate energization of the stator coils 36 . At the point in time t ₁ , this generation of a drive torque is ended and the electric machine 12 is brought into an operating mode which acts as a generator, in which, by appropriate connection of the stator coils 36 by means of power electronics, not shown, through the magnetic interaction with the moving rotor permanent magnets 28 a current flow is induced in the windings of the stator coils 36 and accordingly a braking torque is generated on the rotor arrangement 20 . Due to the established speed Umsetzverhältnisses between rotor assembly 20 and drive shaft 18 and planet carrier 52 of the drive assembly, the rotor assembly 20 rotates at an idling speed of about 500 revolutions per minute of about 2000 revolutions per minute. At time t ₂ , the driver of a vehicle operates an accelerator pedal, so that the speed of the drive unit now increases and the idling speed range is left. Accordingly, the speed of the rotor arrangement 20 represented by the curve R now also rises, but steeper due to the speed conversion ratio that has been set up. In order, as explained below, to let the electric machine 12 work with the greatest possible efficiency in generator mode and to further prevent the rotor arrangement 20 from reaching a speed range in which irreversible damage to the same cannot be excluded, for example a speed range of more than 6000 revolutions per minute, n _switching of z. B. 4000 revolutions per minute at time t ₃ now triggers a switching operation in which from the gear conversion stage with a higher conversion ratio to one or the gear conversion stage with a lower conversion ratio, for example the illustrated or described gear conversion stage with a conversion ratio of 1 is switched. If the switching or limit speed n _{switching is} reached and exceeded at the time point t ₃ , which can be detected, for example, by continuous detection or monitoring of the speed of the drive shaft 18 or the speed of the rotor arrangement 20 , this is changed by changing the connection of the stator coils 36 braking torque generated on the rotor arrangement 20 is reduced to a small braking torque, for example in the range of 0. The result of this is that essentially no more torque is now transmitted between the rotor arrangement 20 and the planet gear carrier 52 , and thus the ring gear 62 is now essentially no longer supported on the stator carrier 32 via the clutch arrangement 64 . If this essentially torque-free state is reached at time t ₄ , the opening or deactivation of clutch arrangement 64 is now induced, which is then disengaged at time t ₅ . At this point in time t ₅ , the ring gear 62 is therefore no longer blocked against rotation and the torque flow via this gear conversion stage is completely interrupted. This can be detected, for example, by comparing the speed of the drive shaft 18 and the speed of the rotor assembly 20 . At the time t _5, the clutch arrangement disables 64 and released, the ring gear 62 for rotation, said release occurs due to the absence of a torque to be transmitted even with a form fit acting clutch assembly 64 is substantially smoothly, the Beschal will now by changing processing of the stator coils 36 at time t ₅ started to build up an increased braking torque on the rotor arrangement 20 again, which was finally finally reached at time t ₆ . Depending on the existing operating conditions, this can be done up to the maximum permissible braking torque, which then leads to the fastest possible deceleration of the rotor arrangement 20 . If the braking torque is essentially constant, the speed of the rotor arrangement 20 will change substantially constantly between the times t ₆ and t ₇ and will approximate the likewise changing speed of the drive assembly 16 , which here specifies the target speed to be set for the rotor arrangement.

Due to the continuous monitoring of the speed of the drive unit 16 and the speed of the rotor arrangement 20, it can be detected at time t ₇ that the difference between these speeds is now very small, ie the speed deviation between the speed of the rotor arrangement 20 and the speed of the drive unit 16 is now in an area in which an essentially shock-free coupling of the rotor arrangement 20 to the drive shaft 18 via the freewheel 56 or possibly a switchable clutch could take place. If the state is reached at time t ₇ in which the rotational speed of the rotor arrangement 20 matches the rotational speed of the drive unit 16 to a minimal deviation, the generation of the braking torque on the rotor arrangement 20 is ended, so that now finally an im essential torque transmission-free state is reached. Here, however, the speed gradient of the drive unit 16 is additionally monitored according to the invention. If the speed of the drive unit 16 changes only relatively slowly, it can be assumed that even with a spontaneously starting freewheel 56 or with a spontaneously engaging clutch, due to the relatively small speed difference or the slowly changing speed of the drive unit 16, there is essentially no switching shock becomes. However, the change in speed of the drive unit 16 is relatively high, for example in a range of more than. , , Revolutions / min ² , the abrupt onset of the freewheel 56 or the engagement of a possibly form-fitting clutch would lead to an abrupt increase in the speed of the rotor arrangement 20 and thus to a switching shock which was unpleasantly noticeable in the vehicle. According to the invention, therefore, in this state, in which the speed change of the drive unit is above the threshold value, at time t ₈ , the speed change of the rotor arrangement 20 is adapted to the speed change of the drive unit 16 . Since the rotor arrangement 20 was previously in a braking state, a drive torque must now be generated at the rotor arrangement 20 from time t _{8 in} order to adapt to an increasing speed of the drive assembly 16 , as can be seen in FIG. 4b) accelerate them now and adapt their speed change to the speed change of the drive unit. This lasts until a point in time t ₉ , at which then there is an essentially complete correspondence between the speed of the drive shaft 18 and the speed of the rotor arrangement 20 and the speed gradient of the drive shaft 18 and the speed gradient of the rotor arrangement 20 . It is therefore engaged when using a controllable clutch starting at time t ₉ and thus begins to establish the torque connection between the planet gear carrier 52 and the rotor assembly 20 . When a freewheel is used, this becomes automatically effective when the rotational speed coincidence is achieved, so that from time t ₁₀ the complete frictional connection between the drive shaft 18 and the rotor arrangement 20 is established, but now the lower conversion ratio of 1 is present. From time t ₁₀ , rotor arrangement 20 and drive shaft 18 therefore rotate at the same speed and rotor arrangement 20 or electric machine 12 can now be used again to generate electrical energy.

In this state, which is present from the time t ₁₀ and provides a torque transmission connection from the drive shaft 18 via the planet gear carrier 52 and the freewheel 56 to the rotor arrangement 20 , a further advantageous effect of using a freewheel 56 can be felt. If torsional vibrations occur in the area of the drive shaft 18 , these are transmitted to the rotor assembly 20 only in their half-wave region accelerating with respect to the rotor arrangement 20 , but as soon as the torsional vibration transitions into the decelerating half-wave region, the freewheel arrangement 56 decouples. As a result, such torsional vibrations can only be felt to a lesser extent in the area of the electric machine 12 , and thus power fluctuations will also occur to a lesser extent.

A shifting operation in which, due to a decrease in the speed of the drive unit, a gearbox conversion stage with a lower speed conversion ratio is switched to a gearbox conversion stage with a higher speed conversion ratio is shown in FIGS . 5a) and 5b). It is assumed here that, at time t _2, the speed of the drive assembly 16 drops below the threshold value n _switching of, for example, approximately 1500 revolutions per minute. It can be seen that the braking torque generated and thus also the electrical power generated by the electric machine 12 also decrease. If a time interval .DELTA.t has passed since reaching and exceeding, in the present case exceeding in the negative sense, then at time t ₃ , the torque transmitted between the drive unit 16 and the rotor arrangement 20 is reduced. Here too, as can be seen in FIG. 5 b), the braking torque that is absorbed or generated on the rotor arrangement 20 is reduced by appropriate connection of the stator coils 36 . At time t ₄ , a state is reached again in which, due to the fact that essentially no more torque is transmitted between the drive shaft 18 and the rotor arrangement 20 , the clutch arrangement effective at this time, for example the freewheel 56 , is load-free. When a controllable clutch is used, it is now opened and is in a disengaged state at time t ₅ , so that from this point in time there is no torque transmission connection between the drive shaft 18 and the rotor arrangement 20 . This separation can also be detected again by monitoring the speed of the drive shaft 18 and the speed of the rotor arrangement 20 . Between the time t ₅ and a time t ₆ , a drive torque is generated on the rotor arrangement 20 by energizing the stator coils 36 , so that from time t ₆ the rotational speed of the rotor arrangement, represented by the curve R in FIG. 5 a), begins to increase in accordance with the drive torque generated.

From FIGS. 4a) and 5a) it can be seen that the respective limit speeds or switching speeds n _switching for triggering a switching process in the transmission arrangement with increasing speed of the drive unit 16 and with falling speed of the drive unit 16 can differ in order to provide a hysteresis effect here . For example, the zoom drawn on the falling speed of the drive assembly 16 limit speed n _shift may be higher than the range used with increasing rotational speed of the drive assembly 16 limit speed n _switching.

It should be noted that when the freewheel 56 shown in the figures is used, a drive torque is already generated on the rotor arrangement 20 from time t ₄ , so that it accelerates and the freewheel 56 due to the fact that the speed of the rotor arrangement voltage 20 increased with respect to the speed of the drive unit 16 , automatically switches to a non-torque-transmitting state.

Due to the applied drive torque, the speed of the rotor arrangement 20 now moves in the direction of a target speed, which can be obtained, for example, by multiplying the speed of the drive assembly 16 by the speed conversion ratio that is used in the gear conversion step to be set up below is present. If, as in the exemplary embodiment shown, the drive assembly 16 has reached the state at a speed of approximately 700 revolutions per minute and the speed conversion ratio of the gear conversion stage to be set up is in the range of 4, then a target speed for the rotor arrangement 20 results in the range of 2800 revolutions per minute. At this target speed, the speed of the rotor arrangement 20 is moved between the times t ₆ and t ₇ . At time t ₇ , the speed of the rotor arrangement 20 has assumed a value that is relatively close to the target rotor speed, ie the deviation between these two speeds is now only slight. The generation of a drive torque in the rotor arrangement 20 is therefore terminated from the time t ₇ , so that due to the existing friction effects at the time t _8, the speed of the rotor arrangement 20 almost corresponds to the speed of the drive unit 16 . Here, too, the change in the speed of the drive unit 16 can be observed again, and if the change has again exceeded a certain threshold value, as already described above, between the times t ₈ and t ₉ by applying an appropriate drive torque or possibly a braking torque to the rotor arrangement 20, a correspondence between the change in speed of the drive assembly 16 and the change in speed of the rotor arrangement 20 can be generated. If this is the case, from time t ₉ the clutch arrangement 64 is energized, that is to say activated, in order to now lock the ring gear 62 in a rotationally fixed manner without generating any shift shock and to activate the transmission conversion stage, in which, for example, a speed conversion ratio of 4 is present. From time t _{10 there} is again the non-positive and torque-transmitting connection between the drive shaft 18 and the rotor arrangement 20 of the electric machine 12 .

The switching procedures described above can thus be achieved that when switching between different gear implementations also with different speed conversion ratios Use of form-fitting coupling arrangements to prevent the occurrence of Switching surges can be avoided. It is irrelevant whether one of the Transmission conversion stages have a speed conversion ratio of 1, such as this has been shown above. Also switching operations between Gear conversion stages, which of 1 different speed conversion can have relationships as described above by be performed. It is also possible to have multi-stage or multi-course Use gearboxes in which between three gearbox conversion stages  can be selected, in which case, for example, successively two upshifts or two downshifts such as described above can be performed. Likewise, on the way described above in a gear conversion stage can be switched whose speed conversion ratio is less than 1.

As described in particular with reference to the switching process in FIG. 5, it may be advantageous to wait a predetermined time Δt after reaching or exceeding or falling below the switching speed n _switching until the switching process is initiated. In this way, it can be avoided that an only brief change in the speed of the drive assembly 16 or only a short-term reaching and falling below or exceeding the switching speed n _switching leads to an unnecessary switching process, which is caused, for example, by an immediately following speed increase or Speed drop in the speed of the drive unit would have to be canceled again or reversed.

FIGS. 6 and 7 illustrate why in particular in the generator operation of the electric machine 12, it is advantageous to change the speed conversion ratio. Thus, 6 seen in FIG. The course of the maximum producible by the electric machine 12 electrical power in dependence on the rotational speed n _k of the drive shaft 18. For a speed conversion ratio of x, for example 1, there is a gradual increase which reaches a maximum value, whereupon a gradual decrease occurs again. If the speed is translated higher, ie the rotor arrangement 20 rotates at a higher speed in this regard, which is represented by the curve I <x, this curve is compressed, so that the maximum achievable power is already available at a significantly lower speed of the drive shaft. It is therefore advantageous to choose the switching speed n _switching at the intersection of the maximum power curves available for the two speed conversion ratios when a switching operation is to be carried out with regard to the maximum achievable electrical power in generator mode. If the switching speed n _{switching is} exceeded, the gearbox conversion stage with a lower speed conversion ratio is selected; if the switching speed n _{switching is} not exceeded or undercut, the gearbox conversion stage with a higher speed conversion ratio remains or is selected.

FIG. 7 also shows lines or ranges of constant efficiency η. Lines a, b are assigned to the power curve for the higher speed conversion ratio, and lines c, d are assigned to the power curve for the lower speed conversion ratio. Furthermore, lines a and c, which enclose a larger area, denote lines of a constant but lower efficiency η, and lines b and d denote lines or regions of a constant but higher efficiency η. In a state in which the maximum possible power is not required by the electric machine 12 , for example because a system to be fed with electrical energy does not make high power demands, but in which the electric machine 12 operates in a medium power range, it is advantageous to use the Do not select the switching speed with a view to the maximum possible output, but to select it with a view to the optimal efficiency of the electric machine. This is illustrated in FIG. 7 on the basis of the target power P _S. If, starting from a state with a low speed n _{k of} the drive shaft 18 with such a power requirement, the electric machine 12 is operated, it is initially within the range a for the higher speed conversion ratio, but outside the range c for the lower speed conversion ratio, whereby here it is assumed that lines a and c denote the same efficiency η and lines b and d are lines of the same efficiency. If the speed of the drive shaft 18 is then increased, an intersection between the lines a and c is increasingly being approached. If this intersection point is exceeded, the area a of the higher speed conversion ratio is now left, so that if the higher speed conversion ratio were maintained, the efficiency η would drop. At the same time, however, an increase in efficiency occurs at the lower speed conversion ratio by entering the area surrounded by line c. It is therefore advantageous, if priority is given to the efficiency of the electric machine 12 , that is to say for a specific power requirement to be operated with optimum efficiency, not to select the _switching speed n _switching as a constant value, but rather for a particular operating state, for example for a To define the respective power requirement in such a way that a switching operation will take place if, by changing the speed of the drive shaft 18, an increase in efficiency would occur in one of the speed conversion ratios and a decrease in the other. For the selection of the shift strategy shown in FIG. 6 as a function of the maximum achievable electrical power and the shift strategy shown in FIG. 7, in which the shift speed for a particular operating state, for example a particular power requirement, is selected with regard to the optimization of the efficiency, As already mentioned above, the amount of the performance requirement can be used. If the power requirement is high, for example in the range of over 60% of the maximum possible electrical power in generator operation, the switching speed according to FIG. 6 can be selected; if the power requirement is lower, the switching speed according to FIG. 7 can be selected. If the power requirement is only minimal, for example below 30% of the maximum possible electrical power in generator operation, the procedure can be such that a switching operation occurs only once, as shown in FIG. 4 a), when the vehicle is started and when the idling speed is left if the shift speed n _{shift is} carried out, but then the transmission conversion stage is maintained, regardless of how the speed of the drive unit changes. In this way, driving comfort can be improved and the load on the transmission arrangement can be minimized by minimizing the switching operations to be carried out.

Furthermore, it can be provided that when the rotational speed of the rotor arrangement 20 approaches a critical range, the force coupling between the drive shaft 18 and the rotor arrangement 20 is interrupted, for example by disengaging a clutch arrangement inserted instead of the freewheel 56 . A subsequent re-engagement can be carried out as described above. Such a separation of the torque transmission can also take place when a predetermined speed gradient is exceeded.

The present invention provides a drive system with an electric machine and a gear arrangement, in which the smooth switching operations in the area of the gear arrangement can be carried out without letting a friction clutch grind and thus a relatively large amount of wear. The structure according to the invention is very simple and thus relatively robust and inexpensive. In various operating situations, the use of the freewheel offers special advantages in addition to the fact that there is no need to control an additional clutch. This is in particular a state in which, as described above, torsional vibrations occur, or, for example, a state in which when switching operations are carried out in a vehicle transmission when the throttle is applied or when the vehicle or the drive unit is braked strongly, a lower rotational speed spontaneously occurs on the side of the Drive shaft 18 adjusts as on the side of the rotor 20 . The rotor 20 can then initially rotate essentially freely, so that electrical energy can still be generated with relatively high efficiency even when the drive shaft 18 rotates more slowly. If a spontaneous change in the speed of the drive shaft when releasing the rotor arrangement 20 could result in a switching shock, the procedure described above can be used when using a switchable clutch. In the system according to the invention, in which a gear conversion stage with a higher speed conversion ratio is generally used to start a drive unit, the number of gearshifts to be carried out in the transmission arrangement can be further reduced if, for example, when a drive unit that is at operating temperature is restarted, Access stage is accessed that has a lower speed conversion ratio. In this state, the drive torque required to start the drive unit is generally lower, so that such a gear conversion stage can also be used. It is also possible to work with a lower speed conversion ratio, for example in a ratio of 1, in the case of an overheated electric machine in the motorized, that is to say driving operation thereof, for example during a starting process, when delivering a supporting torque or during active vibration damping.

Further, it should be noted that between the output member, that is to say the planet carrier 52, and the rotor assembly 20 in the illustrated embodiment effective coupling assembly, the freewheel assembly 56 is not directly between these two components or subassemblies must act. Further intermediate components or assemblies can be provided, in particular a further gear train can be provided, so that even with an effective clutch arrangement, ie with an effective freewheel arrangement 56 or a different type of clutch arrangement, a speed conversion ratio different from 1 is provided.

Claims (40)

1. Drive system comprising an electric machine ( 12 ) and an output member ( 52 ) that can be coupled or coupled to a drive shaft ( 18 ) of a drive unit ( 16 ) for rotation, by means of which electric machine ( 12 ) the drive shaft ( 18 ) can be driven to rotate or / and when the drive shaft ( 18 ) rotates, electrical energy can be obtained, the electric machine ( 12 ) comprising a stator arrangement ( 30 ), characterized in that it is connected to the output member ( 52 ) via a gear arrangement ( 14 ) with a variable speed conversion ratio for rotation or connectable rotor arrangement ( 20 ) and by a first coupling arrangement ( 56 ), by means of which a torque transmission connection between the rotor arrangement ( 20 ) and the output member ( 52 ) can be established. That the first clutch assembly (56) comprises a freewheel arrangement (56) 2. A drive system according to claim 1, characterized in that, by means of which a torque substantially only by the output member (52) to the rotor assembly (20) is out transferable. 3. Drive system according to claim 1 or 2, characterized in that the gear arrangement ( 14 ) has at least an optionally activatable gear conversion stage, in which, when activated, a speed ratio speed of the rotor arrangement / speed of the output member ( 52 ) is greater than 1 . 4. Drive system according to claim 3, characterized in that in the non-activated state of the at least one transmission conversion stage with a speed ratio different from 1 with torque-transmitting first clutch arrangement ( 56 ), the speed ratio is 1 . 5. Drive system according to claim 3 or 4, characterized in that the at least one gear conversion stage with a speed ratio different from 1 can be activated by selectively activating a reaction torque support arrangement ( 64 ). That the Reaktionsmomentenabstützanord voltage (64) 6. The drive system of claim 5, characterized in that a preferably electromagnetically activatable and / or deactivatable and preferably positively and / or frictionally acting second clutch assembly (64). 7. Drive system according to one of claims 1 to 6, characterized in that the gear arrangement ( 14 ) comprises a planetary gear, which comprises:

• - A sun gear ( 48 ) connected to the rotor arrangement ( 20 ),
• - A ring gear ( 62 ), which can either be fixed against rotation or is released for rotation,
• - At least one on a planet carrier ( 52 ) rotatably supported planet gear ( 60 ) which is connected to the sun gear ( 48 ) and the ring gear ( 62 ) in torque transmission connection, the tarpaulin tenradträger ( 52 ) forms the output member ( 52 ) or connected to this is.

8. Drive system according to claim 7 and one of claims 5 or 6, characterized in that the ring gear ( 62 ) by the reaction torque support arrangement ( 64 ) can be fixed against rotation. 9. Drive system according to claim 7 or 8, characterized in that an interaction region ( 24 ) of the rotor arrangement ( 20 ) via a torsional vibration damper arrangement ( 40 ) is connected to the sun gear ( 48 ). 10. Drive system according to one of claims 1 to 9, characterized in that the rotor arrangement ( 20 ) surrounds the stator arrangement ( 30 ) radially on the outside. 11. Drive system according to the preamble of claim 1 and / or optionally in connection with the characterizing part of one of claims 1 to 10, characterized in that the stator arrangement ( 30 ) comprises a stator carrier ( 32 ) which is in a radially outer region carries an interaction region ( 34 ) of the stator arrangement ( 30 ) and surrounds the at least part of a gear arrangement ( 14 ) radially on the outside. 12. Drive system according to claim 11, characterized by a cooling arrangement ( 78 , 80 ) through which the interaction region ( 34 ) of the stator arrangement ( 30 ) and the gear arrangement ( 14 ) can be cooled. 13. The drive system of claim 12, characterized in that the cooling arrangement (78, 80) includes a refrigerant channel arrangement (78, 80) in the stator (32), which coolant duct arrangement (78, 80) can be brought into communication with a source of coolant or standing. 14. Drive system according to one of claims 1 to 13, characterized in that the electric machine ( 12 ) on an auxiliary drive side (N) of the drive unit ( 16 ) can be positioned or positioned. 15. Drive system according to one of claims 1 to 14, characterized in that the rotor arrangement ( 20 ) is arranged coaxially with the drive shaft ( 18 ) when the output member ( 52 ) is coupled to the drive shaft ( 18 ). 16. Drive system according to one of claims 1 to 15, characterized in that the electric machine ( 12 ) preferably in the region of a stator carrier ( 32 ) via an elastic connection arrangement ( 72 ) with a fixed assembly, preferably the drive unit ( 16 ), connected or connectable is. 17. A method for controlling a drive system, in particular a drive system according to one of the preceding claims,
wherein the drive system an electric machine (12) and having a drive shaft (18) has a drive unit (16) coupled for rotation output member (52), said tromaschine by Elek (12) the drive shaft (18) for rotation can be driven and / or electrical energy can be obtained when the drive shaft rotates, the electric machine ( 12 ) further comprising a stator arrangement ( 30 ) and a rotor arrangement ( 20 ) which can be connected or connected to the output member ( 52 ) via a transmission arrangement ( 14 ) with a variable speed conversion ratio for rotation ), the gear arrangement ( 14 ) having at least two gear conversion stages with different speed ratios of the rotor arrangement / speed of the output member ( 52 ),
the method for performing a shift from a gearbox conversion stage to a gearbox conversion stage to be set up comprising the following steps:

• a) determining the speed of the drive shaft ( 18 ) and / or determining the speed of the rotor arrangement ( 20 ),
• b) when the speed of the drive shaft ( 18 ) or the speed of the rotor assembly ( 20 ) reaches a predetermined limit speed (n _switching ), changing a torque transmitted between the rotor assembly ( 20 ) and the output member ( 52 ) to one Decoupling value,
• c) if the torque transmitted between the rotor arrangement ( 20 ) and the output element ( 52 ) is in the range of the decoupling value, interrupting the torque transmission connection between the output element ( 52 ) and the rotor arrangement ( 20 ),
• d) changing the speed of the rotor arrangement ( 20 ) in the direction of a target rotor speed assigned to the gear conversion stage to be set up,
• e) when the speed of the rotor arrangement ( 20 ) is in the range of the target rotor speed, establishing the torque transmission connection between the output member ( 52 ) and the rotor arrangement ( 20 ) to obtain the gear conversion stage to be set up.

18. The method according to claim 17, characterized in that the target rotor speed is a speed which is obtained by multiplying the speed of the drive shaft ( 18 ) by the speed ratio of the gear conversion stage to be set up. 19. The method according to claim 17 or 18, characterized in that step e) comprises a step e '), in which, when the speed of the rotor arrangement ( 20 ) is in the range of the target rotor speed, a speed change of the rotor arrangement ( 20 ) is adapted to a change in speed of the drive shaft ( 18 ), the torque transmission connection between the rotor arrangement ( 20 ) and the output member ( 52 ) being established if the change in speed of the rotor arrangement ( 20 ) is also adapted to the change in speed of the drive shaft ( 18 ) . 20. The method according to claim 19, characterized in that step e ') is carried out only when the speed change of the drive shaft ( 18 ) is higher than a threshold speed change. 21. The method according to any one of claims 17 to 20, characterized in that in at least one gear conversion stage, a freewheel arrangement ( 56 ) is provided, through which a torque is transmitted essentially only from the output member ( 52 ) to the rotor arrangement ( 20 ) can. 22. The method according to claim 21, characterized in that when switching from one gear conversion stage to another gear conversion stage with a higher speed ratio, step b) comprises step b ') for generating a drive torque in the rotor arrangement ( 20 ) in order to change the torque transmitted between the rotor arrangement ( 20 ) and the output member ( 52 ) to a value in the range of 0 as the decoupling value, and that in step c) the interruption of the torque transmission connection occurs automatically when the decoupling value is reached or exceeded . 23. The method according to any one of claims 17 to 22, characterized in that the speed ratio is 1 in one of the gear conversion stages and that the speed ratio is greater than 1 in at least one of the other gear conversion stages. 24. The method according to claim 21 and claim 23, characterized in that the freewheel arrangement ( 56 ) is provided in that gear conversion stage whose speed ratio is 1 . 25. The method according to any one of claims 17 to 24, characterized in that when switching from a gearbox conversion stage with a lower speed ratio to a gearbox conversion stage with a higher speed ratio, step d) comprises generating a drive torque in the rotor arrangement ( 20 ) . 26. The method according to claim 25, characterized in that in step e), when the speed of the rotor arrangement ( 20 ) is in the range of the target rotor speed, the generation of the drive torque is ended. 27. The method according to any one of claims 17 to 26, characterized in that when switching from a gearbox conversion stage with a higher speed ratio to a gearbox conversion stage with a lower speed ratio step d) comprises generating a braking torque in the rotor arrangement ( 20 ) . 28. The method according to claim 27, characterized in that in step e), when the speed of the rotor arrangement ( 20 ) is in the range of the target rotor speed, the generation of the braking torque is ended. 29. The method according to any one of claims 17 to 28, characterized in that step b) reducing a braking torque generated in the rotor arrangement ( 20 ), preferably to a value in the range of 0, and optionally generating a drive torque in the rotor arrangement ( 20 ). 30. The method according to any one of claims 17 to 29, characterized in that in step b) the torque transmitted between the output member ( 52 ) and the rotor arrangement ( 20 ) is only changed when one has reached the limit speed (n _switching ) predetermined time has passed. 31. The method according to any one of claims 17 to 30, characterized in that in step b) the torque transmitted between the output member ( 52 ) and the rotor arrangement ( 20 ) is only changed if after reaching the limit value (n _switching ) The speed of the drive shaft ( 18 ) or of the rotor arrangement ( 20 ) remains beyond the limit speed (n _switching ) for a predetermined period of time. 32. The method according to any one of claims 17 to 31, characterized in that the limit speed (n _switching ) is determined as a speed, when exceeded, the maximum power output of the electric machine ( 12 ) higher when generating electrical energy in the gearbox conversion stage to be prepared than when the gearbox conversion stage is set up. 33. The method according to any one of claims 17 to 32, characterized in that the limit speed (n _switching ) for a respective operating state is determined as a speed, when exceeded when the gear conversion stage to be set up, the efficiency of the electric machine ( 12 ) when generating elec tric energy is higher than with the gearbox conversion stage. 34. The method according to claim 33, characterized in that the operating state is determined at least by the power requirement on the electric machine ( 12 ). 35. The method according to any one of claims 32 to 34, characterized in that the limit speed (n _switching ) for optimizing the maximum power output of the electrical machine ( 12 ) is determined when generating electrical energy, if in one by the electrical machine ( 12 ) with electrical energy supplied system has a high power requirement, preferably in the range of 60% -100% of the maximum power of the electric machine, when generating electrical energy, and that the limit speed (n _switching ) is determined to optimize the efficiency of the electric machine ( 12 ) when generating electrical energy , if the power requirement of the system is in the range of less than 60% of the maximum power of the electric machine ( 12 ) when generating electrical energy. 36. The method according to any one of claims 17 to 35, characterized in that a gear conversion stage with a higher speed ratio, preferably in the range of 4, is set up to start the drive unit ( 16 ), and that after reaching the limit speed (n _shift ) one Gear conversion stage with a lower speed ratio, preferably in the range of 1, is set up. 37. The method according to claim 36, characterized in that after setting up the transmission conversion stage with a lower speed ratio, switching of the transmission conversion stages does not take place regardless of the speed of the drive shaft ( 18 ) or the rotor arrangement ( 20 ). 38. The method according to claim 37, characterized in that a changeover of the transmission conversion stage is essentially omitted if a power requirement of a system supplied with electrical energy by the electric machine ( 12 ) is in a lower range, preferably less than 30%. the maximum power of the electric machine ( 12 ) when generating electrical energy. 39. The method according to any one of claims 17 to 38, characterized in that the gear arrangement ( 14 ) comprises a planetary gear, which comprises:

• - A sun gear ( 48 ) connected to the rotor arrangement ( 20 ),
• a ring gear ( 62 ) which can be fixed against rotation by a clutch arrangement ( 64 ),
• - At least one on a planet carrier ( 52 ) rotatably supported planet gear ( 60 ) which is connected to the sun gear ( 48 ) and the ring gear ( 62 ) in torque transmission connection, the tarpaulin tenradträger ( 52 ) forms the output member ( 52 ) or connected to this is
• a further clutch arrangement ( 56 ), by means of which a preferably substantially direct torque transmission connection can be established between the planet gear carrier ( 52 ) and the rotor arrangement ( 20 ),

wherein the ring gear ( 62 ) is held essentially non-rotatably by the clutch arrangement ( 64 ) and the further clutch arrangement ( 56 ) has essentially no torque transmission connection between the rotor arrangement ( 20 ) and the planet carrier ( 52 ) for setting up a transmission conversion stage with a higher speed ratio. provides, and wherein to set up a gearbox conversion stage with a lower speed ratio, preferably a speed ratio of 1, the clutch arrangement ( 64 ) essentially does not fix the ring gear ( 62 ) against rotation and the further clutch arrangement ( 56 ) establishes a torque transmission connection between the planet carrier ( 52 ) and the rotor arrangement ( 20 ). 40. The method according to claim 39, characterized in that said second clutch assembly (56) comprises a freewheel arrangement (56) through which a torque substantially only by the planet carrier (52) to the rotor assembly (20) is transferable out.