DE102018129936A1 - Electromechanical drive arrangement for a motor vehicle - Google Patents

Abstract

The invention relates to an electromechanical drive arrangement for a motor vehicle with an electric motor with a stator and a rotor, a reduction gear, which is designed as a spur gear and has an input shaft and an output shaft, the reduction gear having a first spur gear stage with a first transmission ratio and a second Helical gear stage with a second gear ratio that is opposite to the first gear ratio, the first spur gear stage has a first drive spur gear and a first driven spur gear, the second spur gear stage has a second drive spur gear, an intermediate gear arrangement and a second driven spur gear, in the first gear stage a first freewheel is provided, in the second gear stage is provided with a second freewheel, the first freewheel comes into a coupling state when the input shaft rotates in a first direction of rotation, the second freewheel when the egg rotates gear shaft in a coupling state opposite to the first direction of rotation, the input shaft is driven by the first electric motor, a second electric motor is provided which has a second rotor and a second stator, and the second electric motor is kinematically connected to the via the intermediate wheel arrangement second gear stage is coupled.

Description

Field of the Invention

The invention relates to an electromechanical drive arrangement for a motor vehicle with an electric motor, a reduction gear, which is designed as a spur gear, and an axle differential gear, for branching the drive power via the reduction gear to a first and a second wheel drive shaft.

Out DE 10 2015 110 839 A1 such a drive arrangement is known. The spur gear is designed as a two-stage switchable gear. The spur gear has an input shaft and an output shaft. Two drive spur gears sit on the input shaft, two driven spur gears sit on the output shaft and an output gear provided to continue the power. The first drive spur gear seated on the input shaft and the driven first spur gear of the output shaft meshing with it implement a first transmission ratio. The second drive spur gear seated on the input shaft and the second spur gear of the output shaft meshing with it implement a second transmission ratio. The second drive spur gear can be coupled to the input shaft via a coupling device. The two wheels that are seated on the output shaft and driven thereby are coupled to the output shaft via freewheels, so that the output shaft can overtake the driven wheel that is not carrying the load, but is traveling in the same direction. One of the freewheels is switchable and can be bridged.

In the case of widespread gear concepts with spur gear stages, the gears to be shifted, as already described above, are shifted with the aid of clutches and synchronizations. In order to be able to engage a gear while driving, the motor is first kinematically separated from the input shaft of the transmission by stepping on the clutch. The speed of the input shaft is then synchronized with the speed of the selected gear, taking into account the target gear ratio. Only then is there a positive connection of the input shaft to the wheel of the desired gear. This process is disadvantageous in automated transmission concepts for driving comfort, since the internal combustion engine is separated from the transmission during the switching processes. Accordingly, temporarily no power flows through the transmission. A so-called traction force interruption occurs, which the driver can perceive as a longitudinal dynamic vibration. In manually shifted transmissions, this process is less critical, since the driver himself initiates the shifting process and the drop in tractive force is causally related to the shifting process that the driver himself handled. In automated transmission concepts, the driver is more or less surprised by the shift-related longitudinal dynamic vibrations. With a dual clutch transmission, this problem can be avoided by blending the closing and opening of the clutches. This cross-fading can also take place under load so that there is no, or at least insignificant, interruption of the tractive force.

Object of the invention

The invention has for its object to provide an electromechanical drive device which is characterized by a robust and inexpensive to implement construction and an advantageous mechanical switching and operating behavior.

Solution according to the invention

• - einem ersten Elektromotor mit einem ersten Stator und einem ersten Rotor,
• - einem Reduktionsgetriebe, das als Stirnradgetriebe ausgeführt ist und eine Eingangswelle sowie eine Ausgangswelle aufweist, wobei
• - das Reduktionsgetriebe eine erste Stirnradstufe mit einem ersten Übersetzungsverhältnis und eine zweite Stirnradstufe mit einem zweiten Übersetzungsverhältnis aufweist,
• - die erste Stirnradstufe ein erstes Antriebsstirnrad und ein Abtriebsstirnrad aufweist,
• - das erste Antriebsstirnrad auf der Eingangswelle sitzt und in das erste Abtriebsstirnrad eingreift, das auf der Ausgangswelle sitzt,
• - die zweite Stirnradstufe ein zweites Antriebsstirnrad, eine Zwischenradanordnung und ein zweites Abtriebsstirnrad aufweist und dabei zur ersten Stirnradstufe gegensinnig übersetzt,
• - in der ersten Getriebestufe ein erster Freilauf vorgesehen ist,
• - in der zweiten Getriebestufe ein zweiter Freilauf vorgesehen ist,
• - der erste Freilauf bei Drehung der Eingangswelle in einer ersten Drehrichtung in einen Koppelungszustand gelangt,
• - der zweite Freilauf bei Drehung der Eingangswelle in einer der ersten Drehrichtung entgegengesetzten, zweiten Drehrichtung in einen Koppelungszustand gelangt,
• - die Eingangswelle durch den ersten Elektromotor angetrieben wird,
• - ein zweiter Elektromotor vorgesehen ist, der einen zweiten Rotor und einen zweiten Stator aufweist, und
• - der zweite Elektromotor über die Zwischenradanordnung kinematisch an die zweite Getriebestufe angekoppelt ist.

This object is achieved according to the invention by an electromechanical drive arrangement for a motor vehicle with:

• a first electric motor with a first stator and a first rotor,
• - A reduction gear, which is designed as a spur gear and has an input shaft and an output shaft, wherein
• the reduction gear has a first spur gear stage with a first transmission ratio and a second spur gear stage with a second transmission ratio,
• the first spur gear stage has a first drive spur gear and an output spur gear,
• the first drive spur gear is seated on the input shaft and engages in the first output spur gear which is seated on the output shaft,
• the second spur gear stage has a second drive spur gear, an idler gear arrangement and a second driven spur gear and thereby translates in opposite directions to the first spur gear stage,
• a first freewheel is provided in the first gear stage,
• a second freewheel is provided in the second gear stage,
• the first freewheel comes into a coupling state when the input shaft rotates in a first direction of rotation,
• the second freewheel comes into a coupling state when the input shaft rotates in a second direction of rotation opposite to the first direction of rotation,
• - the input shaft is driven by the first electric motor,
• - A second electric motor is provided, which has a second rotor and a second stator, and
• - The second electric motor is kinematically coupled to the second gear stage via the intermediate wheel arrangement.

This advantageously makes it possible to create a drive arrangement in which the transmission ratio can be adapted to the vehicle speed and the current drive torque requirement with high dynamics and without significant interruption of tractive power by changing the direction of rotation of the first electric motor and temporary activation of the second electric motor. As part of a change in the direction of rotation of the first electric motor, the second electric motor can temporarily keep the drive power at a level that compensates for the power contribution of the first electric motor. The power output of the second electric motor can be significantly higher than the permissible permanent load on the second electric motor and the duration of the peak load is usually less than two seconds. The second electric motor can also be used to implement a boost function or to implement a reverse gear function.

Furthermore, energy recuperation in the overrun mode of the vehicle can also be implemented via the second electric motor. The use of the idler gear arrangement for the connection of the second electric motor also makes it possible to use the ratio between the idler gear arrangement and the driven spur gear to increase the torque.

The intermediate gear arrangement can consist of a single intermediate gear which engages in the second drive spur gear and the second output spur gear. The intermediate wheel arrangement can also consist of two intermediate wheels arranged coaxially with one another, which are either directly rigidly coupled to one another or are unidirectionally coupled to one another via the second freewheel.

The drive arrangement can be designed in such a way that it provides one of the translation stages as a translation stage for the primary standard operation. The other transmission stage that can be activated by reversing the direction of rotation of the electric motor can then either be the stage for very high final vehicle speeds or for very high wheel drive torques.

The selection of the respective translation level can be made depending on additional information, so that e.g. when starting from a standing start with an increasing lane, the level with the higher gear ratio is selected by an electronic control device, whereas in a phase with largely no-load sailing operation, the engine direction of rotation is selected for the further drive, at which the gear ratio level for high vehicle speeds takes over the power transfer . The change in gear ratio can take place in the context of a vehicle operating phase in which the engine load of the first engine can also be temporarily applied by the second electric motor, so that the drop in performance during the change in direction of rotation of the first electric motor can be at least largely compensated for by the second electric motor until the first electric motor again makes a contribution to performance. The switching point does not have to be set to a specific engine speed or vehicle speed, e.g. a criterion for switching between the gear ratios can be provided for a relatively wide speed range and the switching takes place if a certain load requirement is temporarily not exceeded in this area, whereby in addition to the compensation effect of the second electric motor in a hybrid vehicle also by appropriate activation of the primary drive further performance contribution can be delivered.

The concept according to the invention makes it possible for the vehicle to assume a rolling state without entrainment of the rotor of the first electric motor, it then being decided as a function of the vehicle speed in the presence of a load request by the control device, with which gear ratio the load request is to be met and the desired one Gear ratio is selected by setting the direction of rotation of the first rotor generating this gear ratio. If the torque requirement is particularly high, the second electric motor can be activated to assist.

In the drive arrangement according to the invention, the first rotor is not necessarily dragged along and when the vehicle is driven by a primary drive, both freewheels can then open without load. It is also possible to make the choice of the transmission ratio dependent on the settings made by the driver. It is thus possible to provide the driver in the area of the operating environment with input devices by means of which the driver can select, for example, a specific “gear” and thus a specific direction of rotation of the motor. Furthermore, it can also have a specific operating mode, for example a sports operating mode choose which results in a switching characteristic optimized for acceleration, or an energy-saving mode in which the first electric motor is active in a speed range which is advantageous in terms of efficiency. It is also possible to make the support characteristics of the second electric motor dependent on the driver's settings so that, for example, in a sport mode the second electric motor provides an additional boost (“boost”) after the temporary power compensation.

The second electric motor can also be used to synchronize the gear sections separated via the freewheels, in particular when switchable lock-up clutches are used, which will be discussed below.

The drive device according to the invention can form a primary drive of a motor vehicle. The drive arrangement according to the invention can advantageously also form a secondary drive for a motor vehicle, while the primary drive is located on the other axis, for example in the form of an internal combustion engine or another electrical machine. The secondary drive, or optionally the entire axis with the secondary drive, can preferably be optionally switched off (AWD disconnection, hang-on coupling).

The drive arrangement according to the invention is preferably designed such that the first freewheel is arranged in the first drive gear. The second freewheel is then preferably arranged in the second drive gear. The freewheels can be designed as positive and / or frictionally coupling freewheels. They can be designed such that the establishment of a coupling state also under the action of tooth reaction forces and e.g. an accompanying at least slight axial displacement of a helically toothed drive wheel is supported.

The drive arrangement is also preferably designed such that a first gear ratio is realized via the first spur gear stage, the amount of which is greater than the amount of a second gear ratio that is implemented via the second spur gear stage. In this case, the first drive gear has a smaller tip circle diameter than the second drive gear. However, it is also possible to coordinate the two gear ratios so that the amount of the first gear ratio is smaller than the second. In this case, the second drive gear has the smaller tip circle diameter and the distances between the drive shaft and the output shaft are bridged by the gear train that is formed by the intermediate gear arrangement and the second output gear.

According to a further preferred embodiment of the invention, the input shaft is aligned coaxially with the first rotor axis, or is driven directly by the first rotor shaft, or is formed by the first rotor shaft.

As an alternative to the above-mentioned variant, it is also possible to design the drive arrangement in such a way that a pre-stage wheel is seated on the input shaft, this pre-stage wheel then being driven by a drive pinion which is seated on the first rotor shaft of the electric motor. It is also possible to connect the first electric motor with the input shaft via a pre-stage transmission, e.g. to couple a planetary gear. The latter can then preferably be arranged coaxially with respect to its central axis to the input shaft.

When an axle differential gear is integrated directly into the drive arrangement, the first and the second driven spur gear or at least one of these gearwheels can be mounted directly on a rotating housing, i.e. sit on the basket of the axle differential. The input shaft and the output shaft are preferably aligned parallel to one another and the axle differential gear can be accommodated directly in the gear housing of the drive arrangement.

The drive arrangement is preferably designed to be arranged in the installed state in a motor vehicle such that the input shaft is oriented transversely to the longitudinal direction of the vehicle. The drive arrangement preferably forms an axle drive module which is arranged in an intermediate region between a left and a right vehicle wheel. Insofar as the drive arrangement functions as a secondary drive, it is preferably seated in the region of the vehicle axle which is further spaced from the primary drive. It is possible to use housing sections of the drive arrangement as connection points for wheel suspension members. The housing of the drive arrangement can act as a front or rear axle support and e.g. Provide bearings for triangular or wishbones, as well as for suspension elements, especially struts or torsion springs.

In the drive arrangement according to the invention, both gear stages are equipped with counter-rotating freewheels. Depending on the direction of rotation of the first electric machine, the power flow takes place either via the first gear or via the second gear and thereby via the idler gear arrangement to the output shaft. By reversing the direction of rotation of the first electric machine, you can switch between two gear ratios.

The transmission of the drive arrangement according to the invention comprises a drive shaft, a Idler gear arrangement, an output shaft and freewheels or overrunning clutches as preferably passive shifting elements.

In a first variant, two gearwheels sit on the drive shaft, each of which is connected to the drive shaft by means of a counter-rotating freewheel. The gears on the output shaft are firmly connected to the shaft. The freewheels of the gear pairs are always executed in opposite directions. In this way, only one gear wheel is driven in each direction of rotation of the electric machine. In first gear, the power flow takes place directly from the drive wheel to the driven wheel. In second gear, the power flow from the drive wheel via the idler gear arrangement to the driven gear takes place. The intermediate gear arrangement compensates for the reversal of the direction of rotation of the first electric machine and the driven gear is driven with the correct direction of rotation again. This enables a gear change in the course of a reversal of the direction of rotation of the first electric machine. In a simplest embodiment, no further switching device is required for this, which reduces the costs, the installation space required and the weight of the transmission. No additional switching actuator is required either. The second electric motor is connected to the intermediate wheel arrangement, and the drive power of the second electric motor is coupled into the intermediate wheel arrangement by the second rotor shaft.

The two freewheels are oriented so that, depending on the direction of rotation of the first rotor shaft, one of the freewheels is load-free and the other actively transmits torque. The roller bearings are preferably located next to the freewheels. The output shaft is preferably at the same time the basket, the web or the revolving housing of a differential gear provided for the power split. This differential gear can be designed in a particularly advantageous manner as a bevel or spur gear differential.

The gear ratios of the two stages can be coordinated in such a way that certain application scenarios can also be met in a particularly advantageous manner, so the high gear stage can be used to optimize efficiency in inner-city operation, e.g. designed for operation at vehicle speeds of up to 60 km / h and the lower gear ratio for operation outside of built-up areas. The stage which comprises the idler gear arrangement is preferably used for the statistically rarer application, so that the power is less frequently supplied by the additional gear engagement of the idler gear arrangement in the driven gear than via the step with a direct engagement of the drive gear in the driven gear of the output shaft.

The second electric motor is located in the second gear stage in a section that runs continuously with the output shaft. The second freewheel is located in the area between the input shaft and the idler gear. The second electric motor is thus separated from the first electric motor via the second freewheel and, when the idler gear is driven by the second electric motor, the second freewheel can temporarily overtake the drive train section leading to the first electric motor without load. The first electric motor cannot build up a counter torque against the drive power of the second electric motor, since in this case the second freewheel opens.

The concept according to the invention enables a power transition which compensates for the drop in drive power of the first electric motor during a change in direction of rotation, so that the driver is not able to detect a drop in tractive force. In the event of a "gear change", the power of the second electric motor is matched to the current power consumption "shortly before switching" of the first electric motor. The corresponding control for this can be designed adaptively and in particular take into account information on the general operating state of the vehicle and set the power consumption of the second electric motor using a model.

Figure list

• 1 eine Schemadarstellung zur Veranschaulichung des Aufbaues einer erfindungsgemäßen elektromechanischen Antriebsanordnung gemäß einer ersten Ausführungsform der Erfindung;
• 2 eine Schemadarstellung zur Veranschaulichung des Aufbaues einer erfindungsgemäßen elektromechanischen Antriebsanordnung ähnlich der Antriebsanordnung nach 1, jedoch mit einer zusätzlichen schaltbaren Überbrückungskupplung
• 3 eine Schemadarstellung zur Veranschaulichung des Aufbaues einer erfindungsgemäßen elektromechanischen Antriebsanordnung gemäß einer dritten Ausführungsform der Erfindung wiederum ähnlich 1, wobei jedoch der erste Freilauf auf der Ausgangswelle sitzt;
• 4 eine Schemadarstellung zur Veranschaulichung des Aufbaues einer erfindungsgemäßen elektromechanischen Antriebsanordnung gemäß einer vierten Ausführungsform der Erfindung, mit einem in die Abtriebswelle integrierten Achsdifferentialgetriebe, sowie zudem mit einem zwischen dem ersten Elektromotor und der Eingangswelle vorgesehenen Vorstufengetriebe, wobei der zweite Freilauf in der Zwischenradanordnung sitzt
• 5 eine Übersichtsdarstellung zur Erläuterung der Aktivitäten der beiden Elektromotoren, der Freiläufe und der Fahrzeuglängsbeschleunigung

Further details and features of the invention will become apparent from the following description in conjunction with the drawing. It shows:

• 1 a schematic representation to illustrate the structure of an electromechanical drive arrangement according to the invention according to a first embodiment of the invention;
• 2nd a schematic representation to illustrate the structure of an electromechanical drive arrangement according to the invention similar to the drive arrangement according to 1 , but with an additional switchable lock-up clutch
• 3rd a schematic representation to illustrate the structure of an electromechanical drive arrangement according to the invention according to a third embodiment of the invention again similar 1 , however, the first freewheel sits on the output shaft;
• 4th a schematic representation to illustrate the structure of an electromechanical drive arrangement according to the invention according to a fourth embodiment of the invention, with an axle differential integrated in the output shaft, and also with a pre-stage transmission provided between the first electric motor and the input shaft, the second freewheel being seated in the intermediate wheel arrangement
• 5 an overview to explain the activities of the two electric motors, the freewheels and the vehicle's longitudinal acceleration

Detailed description of the figures

The representation after 1 shows a first preferred embodiment of an electromechanical drive arrangement according to the invention for a motor vehicle. The drive arrangement comprises a first electric motor E1 with a first stator S1 and a first rotor R1 . The drive arrangement further comprises a reduction gear G , which is designed as a spur gear and an input shaft EW as well as an output shaft AW having.

The reduction gear G comprises a first spur gear stage GS1 with a first gear ratio i1 and a second spur gear stage GS2 with a second and at the same time opposite gear ratio i2 . The first spur gear stage GS1 has a first drive spur gear S1A and a first driven spur gear S1B on. The first drive spur gear S1A sits on the input shaft EW and engages in the first driven spur gear S1B one that's on the output shaft AW sits.

The second spur gear stage GS2 has a second drive spur gear S2A , an idler gear arrangement S2Z and a second driven spur gear S2B on. The second drive spur gear S2A sits on the input shaft EW and reaches into the idler gear Z1 the idler gear assembly S2Z a. The intermediate wheel Z1 engages radially from the outside in the second output spur gear S2B one that's on the output shaft AW sits.

In the drive arrangement according to the invention is between the input shaft EW and the first drive spur gear S1A a first freewheel FR1 intended. It is also between the input shaft EW and the second drive spur gear S2A a second freewheel FR2 intended. The first freewheel FR1 arrives in a first direction of rotation of the input shaft EW in a coupling state and the second freewheel FR2 arrives in one of the first directions of rotation of the input shaft EW opposite direction of rotation in a coupling state.

The first freewheel FR1 is in the first drive gear S1A arranged. The second and the first freewheel FR1 opposite freewheel FR2 is in the second drive gear S2A arranged. Via the first spur gear stage GS1 becomes a first gear ratio i1 realized, the amount in this embodiment is greater than the amount of the second gear ratio i2 that over the second spur gear GS2 is realized.

In this embodiment, the input shaft EW to the rotor axis X of the first electric motor E1 aligned and the input shaft EW is directly through the first rotor shaft RW1 driven or directly by the first rotor shaft RW1 educated.

The drive arrangement comprises a second electric motor E2 . The second electric motor E2 is over its second rotor shaft RW2 to the idler gear Z1 coupled. The second electric motor E2 can be designed to be smaller in performance than the first electric motor E1 and be dimensioned so that load drops during the change of direction of the first electric motor can be compensated by this. The second electric motor is preferred E2 also designed so that sufficient drive power for a reverse gear can be provided. It is possible to switch between the second electric motor E2 and the idler gear Z1 to provide a coupling device through which the second electric motor E2 from the idler gear Z1 is selectively decoupled. This coupling device can interact with the second rotor R2 of the second electric motor E2 be realized, for example, when the second stator is activated S2 performs an axial displacement and thus actuates a clutch.

The representation after 2nd shows a second embodiment of an electromechanical drive arrangement according to the invention for a motor vehicle, which can be integrated as a front or rear axle drive unit in the motor vehicle.

The explanations for the exemplary embodiment apply to this drive arrangement 1 analogous. This second embodiment additionally includes a lock-up clutch UK , to bridge the first freewheel FR1 such that during the overrun operation of the motor vehicle via the first drive spur gear S1A a power transfer (recuperation) into the input shaft EW is feasible. This lock-up clutch enables the first electric motor E1 can also be used for reverse gear and thus also the second electric motor E2 supportive reverse function if necessary.

The lock-up clutch UK is embodied here as an example with a form-fitting claw coupling and couples the first drive spur gear in the engaged state S1A torsionally rigid with the input shaft EW . The lock-up clutch UK is via an actuator device OP brought into a required switching state. The actuator device OP is via a control device C. which also controlled the first electric motor E1 and the second electric motor E2 controls and the speeds of the input shaft EW and the output shaft AW considered. The second electric motor E2 is also over its second rotor shaft RW2 to the idler gear Z1 coupled.

The representation after 3rd shows a third variant of the electromechanical drive arrangement according to the invention. In this embodiment, different from the variants according to the 1 and 2nd , the first freewheel FR1 in the first output gear S1B arranged. The second freewheel FR2 is - as in the embodiments according to the 1 and 2nd - in the second drive gear S2A arranged. Via the first spur gear stage GS1 becomes a first gear ratio i1 realized, the amount in this embodiment is greater than the amount of the second gear ratio i2 that over the second spur gear GS2 is realized. Otherwise, the comments on the 1 and 2nd analogous. The second electric motor E2 is also here on the idler Z1 the idler gear assembly S2Z coupled and thus permanently with the output shaft AW connected to the drive.

The representation after 4th shows a fourth embodiment of an electromechanical drive arrangement according to the invention for a motor vehicle, which in turn can be integrated as a front or rear axle drive unit in a motor vehicle.

This drive arrangement in turn comprises a first electric motor E1 with a first stator S1 and a first rotor R1 as well as a reduction gear G , which is designed as a spur gear and an input shaft EW as well as an output shaft AW having. The reduction gear G also includes a first spur gear stage GS1 with a first gear ratio i1 and a second spur gear stage GS2 with a second and also opposite translation ratio i2 . The first spur gear stage GS1 has a first drive spur gear S1A and a first driven spur gear S1B on. The first drive spur gear S1A sits on the input shaft EW and engages in the first driven spur gear S1B one that's on the output shaft AW sits.

The second spur gear stage GS2 has a second drive spur gear S2A , an idler gear arrangement S2Z and a second driven spur gear S2B on. The idler gear arrangement S2Z here forms an idler gear pair consisting of a first and a second idler gear Z1 , Z2 consists. The second drive spur gear S2A sits on the input shaft EW and reaches into the first idler gear Z1 of the idler gear pair S2Z a. The second idler Z2 of the idler gear pair S2Z engages radially from the outside in the second output spur gear S2B one that's on the output shaft AW sits.

In the drive arrangement according to the invention is between the input shaft EW and the first drive spur gear S1A a first freewheel FR1 intended. There is also between the first idler gear Z1 and the second idler gear Z2 a second freewheel FR2 intended. The first freewheel FR1 arrives in a first direction of rotation of the input shaft EW in a coupling state, and the second freewheel FR2 arrives when the input shaft rotates EW in a direction of rotation opposite to the first direction of rotation into a coupling state.

The first intermediate wheel Z1 and the second idler gear Z2 together form the idler gear arrangement S2Z , which is also referred to below as an idler gear pair. The two idler gears Z1 , Z2 are axially adjacent to each other coaxially and the second freewheel device FR2 is between these two idler gears Z1 , Z2 arranged so that the idler gears Z1 , Z2 Torque can be transmitted in one direction, but are decoupled when loaded in the opposite direction, so that no torque between the intermediate wheels Z1 , Z2 is transmitted. The second freewheel FR2 can be designed in particular as a sprag freewheel and axially between the intermediate wheels Z1 , Z2 be arranged.

The first freewheel FR1 is in the first drive gear S1A arranged. The second freewheel FR2 is in the idler gear pair S2Z arranged. Via the first spur gear stage GS1 a first transmission ratio is realized, the amount of which is greater than the amount of a second transmission ratio, which is via the second spur gear stage GS2 is realized.

The drive arrangement also includes a second electric motor E2 . The second electric motor E2 is over its second rotor shaft RW2 to the second idler gear Z2 coupled. The second electric motor E2 can be designed to be smaller in performance than the first electric motor E1 and be dimensioned in such a way that load drops during this change of direction of the first electric motor E1 can be compensated. The second electric motor is preferred E2 also designed so that sufficient drive power for a reverse gear can be provided. It is possible to switch between the second electric motor E2 and the idler gear Z2 to provide a coupling device through which the second electric motor E2 from the idler gear Z2 is selectively decoupled. These Coupling device can interact with the rotor R2 of the second electric motor E2 be realized, for example, when the second stator is activated S2 performs an axial displacement and thus actuates a clutch. The second electric motor E2 can be between the first and the second drive spur gear S1A , S2A be arranged. As shown, the second electric motor is preferably located on the axle differential AD opposite side of the second idler gear Z2 so the second stator S2 towards the adjacent vehicle wheel RW extends.

Deviating from the embodiments according to the 1 , 2nd and 3rd is the input shaft in this embodiment EW to the rotor axis X of the first electric motor E1 not aligned coaxially, but offset parallel to it. The input shaft EW indirectly becomes a preliminary stage with the involvement GS3 driven. The preliminary stage GS3 includes a spur gear S3A directly through the first rotor shaft RW1 is driven, and also has a spur gear S3B on that on the input shaft EW sits and with the spur gear S3A is engaged.

In the illustrated embodiment, there is now an axle differential AD which is the branching of the drive power to a left and a right wheel drive shaft WSL , WSR serves so integrated in the drive assembly that its circulation housing ADH as an output shaft AW and carrier of the two driven gears S1B , S2B acts. The axle differential AD is preferably designed as a bevel or spur gear differential. The circulation housing ADH is to the rotor axis X arranged coaxially. The first rotor shaft RW1 is designed as a hollow shaft and a section of the wheel drive shaft WSL is coaxial through the first rotor shaft RW1 passed through. The wheel drive shafts WSL , WSR are shown here by way of example as cardan shafts. It is also possible to design the drive arrangement as a rigid axle module, in which case the indicated joints can be dispensed with.

The input shaft EW and the output shaft AW are aligned parallel to each other. The drive arrangement is designed to be arranged in the installed state in a motor vehicle such that the input shaft EW is oriented transversely to the vehicle longitudinal direction. The drive arrangement can form an axle drive module which is located in an intermediate area between a left and a right vehicle wheel LW , RW is arranged.

The freewheels FR1 , FR2 reach depending on the direction of rotation of the rotor R of the first electric motor E1 in a coupling or in a freewheeling state. The freewheels FR1 , FR2 can be designed as friction and / or positive coupling freewheels or overrunning clutches. It is possible to use the freewheels FR1 , FR2 The freewheels can also be used in conjunction with an axial displacement of the spur gears FR1 , FR2 be designed so that they initially take the gears assigned to them as frictionally coupling structures, the gears then being axially displaced due to tooth reaction forces, for example axial forces of a correspondingly designed helical toothing, and then also adopting a positive coupling state with their drive shaft. This results in a particularly high torque transmission capacity and relief of the frictionally coupling freewheels.

Furthermore, it is possible to use the intermediate gear pair provided in the embodiment described above and serving to reverse the direction of rotation S2Z to form as a pair of axially elongated gearwheels and to integrate them into the drive arrangement in such a way that the second idler gear Z2 also in the first driven gear S1B intervenes. On the second driven gear S2B can then be dispensed with. It is also possible to use the first and the second driven gear S1B , S2B identical in construction and via the idler gear pair S2Z then the gear train to the second drive gear S2A close with the second drive gear S2A then preferably has a smaller tip circle diameter than the first drive gear S1A . In this case, the transmission ratio, which is greater in terms of amount, is then via the second spur gear stage GS2 accomplished.

According to a further aspect of the invention, it is also advantageously possible for the two spur gear stages GS1 , GS2 to be interpreted so that the axis X2 of the idler gear S2Z in through the axes XEW , XAW the input shaft EW and the output shaft EW defined axis plane comes to rest. This measure is particularly advantageous for the implementation of the transmission housing, not shown here, in a tub construction.

As far as the gear housing is realized in pot design, the axis can X2 of the idler gear pair S2Z also be offset parallel to the above-mentioned plane. The input shaft EW and the output shaft AW , especially if this is the axle differential AD is then preferably inserted into the gear housing from opposite sides. The conclusion of the gearbox on the side of the electric motor E1 can be accomplished by a connection flange of the electric motor or also by a housing section of the pre-stage transmission GS3 carries within itself.

In a broad sense, the invention consists in an electromechanical drive arrangement for a motor vehicle with two spur gear stages that translate in opposite directions, which form parallel power transfer paths with deviating and opposing gear ratios, these spur gear stages being load-carrying with the inclusion of such freely oriented freewheels that the choice of the direction of rotation of the first electric motor means that effective transmission ratio can be selected for the power transfer to the transmission output and the drive arrangement can provide sufficient drive torque on the output shaft via the second electric motor even in a phase of changing the direction of rotation of the rotor of the first electric motor.

The representation after 5 illustrates the operation of the drive arrangement according to the invention in connection with five operating phases PH1 , PH2 , PH3 , PH4 and PH5 . In the operating phase PH1 the drive motor turns E1 in the positive direction of rotation and generates the drive power. The first freewheel FR1 in the first gear GS1 engages and transmits the drive power through the first gear GS1 on the output shaft AW . The drive power then comes through the output shaft AW and from there to the axle differential AD .

In the operating phase PH2 depending on the power requirement, the drive motor can run in parallel E2 generate another drive torque, which is directly via the idler gear arrangement S2Z and the differential AD is transferred to the wheels.

The gear should now be switched, ie the drive torque of the first motor E1 over the second gear GS2 the torque on the first drive motor must first be transmitted E1 be reduced. There is a reduction in the tractive force on the wheel, but this is due to the second drive motor E2 can be at least partially compensated. This relationship is in the operational phase PH3 look light.

In the operating phase PH4 the direction of rotation is reversed on the drive motor E1 . The first freewheel FR1 the first gear GS1 opens. At the same time, the oppositely oriented freewheel closes FR2 in the second gear GS2 . The drive torque of the first motor E1 can now go through the second gear GS2 be transmitted.

Optionally, you can now in the operating phase PH still the drive motor E2 used or no longer used.

As far as the required drive power exclusively via the first electric motor now rotating in the opposite direction E1 is to be applied in the operating phase PH5 the second electric motor E2 no longer controlled and the performance of the first electric motor E1 about the second freewheel FR2 through the second gear stage GS2 guided.

In the diagram included in the illustration ME the top pair of graphs illustrates the torque of the first electric motor E1 (Full line) and the second electric motor E2 (Dash line).

The RPM diagram below shows the speeds of the rotor shafts. There the full line shows the speed increase of the rotor shaft of the second electric motor E2 , the dashed line the speed curve of the rotor shaft of the first electric motor. The zero crossing of the speed of the rotor shaft of the first electric motor E1 takes place in phase PH3 .

The graph α (dashed line) qualitatively illustrates the longitudinal acceleration of a motor vehicle which is equipped with a corresponding drive device.

The graph M _FR shows that of the freewheels FR1 , FR2 transmitted torque. The solid line shows the torque in the first freewheel FR1 and the dashed line shows the torque from the second freewheel FR2 is transmitted. As can be seen, it is in the phase PH3 on none of the freewheels FR1 , FR2 a torque. The completely missing performance contribution of the first electric motor E1 will in this phase PH3 completely by the second electric motor E2 compensated.

This gearbox concept ensures an uninterrupted gearshift since there is a drive torque on the wheels at all times. The electric motors can optionally be operated temporarily in overload to further increase comfort.

QUOTES INCLUDE IN THE DESCRIPTION

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Patent literature cited

• DE 102015110839 A1 [0002]

Claims (10)

Electromechanical drive arrangement for a motor vehicle with: - a first electric motor (E1) with a first stator (S1) and a first rotor (R1), - A reduction gear (G), which is designed as a spur gear and has an input shaft (EW) and an output shaft (AW), wherein the reduction gear (G) has a first spur gear stage (GS1) with a first gear ratio (i1) and a second spur gear stage (GS2) with a second gear ratio (i2) opposite to the first gear ratio (i1), the first spur gear stage (GS1) has a first drive spur gear (S1A) and a first output spur gear (S1B), the second spur gear stage (GS2) has a second drive spur gear (S2A), an intermediate gear arrangement (S2Z) and a second driven spur gear (S2B), a first freewheel (FR1) is provided in the first gear stage (GS1), a second freewheel (FR2) is provided in the second gear stage (GS2), the first freewheel (FR1) comes into a coupling state when the input shaft (EW) rotates in a first direction of rotation, the second freewheel (FR2) comes into a coupling state when the input shaft (EW) rotates in a second direction of rotation opposite to the first direction of rotation, - The input shaft (EW) is driven by the first electric motor (E1), - A second electric motor (E2) is provided, which has a second rotor (R2) and a second stator (S2), and - The second electric motor (E2) is kinematically coupled to the second gear stage (GS2) via the intermediate wheel arrangement (S2Z). Electromechanical drive arrangement after Claim 1 , characterized in that the second freewheel (FR2) is arranged in a section of the second gear stage (GS2) lying between the input shaft (EW) and the second electric motor (E2). Electromechanical drive arrangement after Claim 1 or 2nd , characterized in that the second electric motor (E2) is permanently or at least independently of the second freewheel (FR2) kinematically coupled to the output shaft (AW). Electromechanical drive arrangement according to at least one of the Claims 1 to 3rd , characterized in that it comprises an axle differential gear (AD) for branching the drive power via the reduction gear (G) to a first and a second wheel drive shaft (WSL, WSR) and in that the axle differential gear (AD) is arranged coaxially with the output shaft (AW) is. Electromechanical drive arrangement after Claim 4 , characterized in that the axle differential (AD) comprises a circulating housing (ADH) and that this circulating housing (ADH) forms part of the output shaft (AW) and in this case carries the first output gear (S1B) and / or carries the second output gear (S2B) Electromechanical drive arrangement according to at least one of the Claims 1 to 5 , characterized in that the first freewheel (FR1) is arranged in the first drive gear (S1A) and / or in that the second freewheel (FR2) is arranged in the second drive gear (S2A). Electromechanical drive arrangement according to at least one of the Claims 1 to 6 , characterized in that a first gear ratio (i1) is realized via the first spur gear stage (GS1), the amount of which is greater than the amount of a second gear ratio (i2) which is implemented via the second spur gear stage (GS2). Electromechanical drive arrangement according to at least one of the Claims 1 to 7 , characterized in that the input shaft (EW) is aligned with the first rotor axis (X). Electromechanical drive arrangement according to at least one of the Claims 1 to 8th , characterized in that the input shaft (EW) is driven directly by the first rotor shaft (RW) or is formed by the first rotor shaft (RW). Electromechanical drive arrangement according to at least one of the Claims 1 to 9 , characterized in that a pre-stage wheel (S3B) is seated on the input shaft (EW) and that this pre-stage wheel (S3B) is driven by a drive pinion (S3A) which is seated on the rotor shaft (RW).

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