DE102015205101B4 - GEARS FOR DISTRIBUTING A DRIVE TORQUE AS REQUIRED - Google Patents

Abstract

Transmission (10) for splitting a drive torque between a first and a second shaft or axle of a vehicle as required, comprising: - a first input shaft (14), which is preferably assigned to an electric motor (22), - a first output shaft (18), which is preferably assigned to a first vehicle shaft, - a second output shaft (20), which is preferably assigned to a second vehicle shaft, - a differential (24) with an input element (28), a first output element (32) and a second output element (34), - a superposition gear (26) with an input element (36) driven by the first drive shaft (14), a first output element (38) and a second output element (42) and - a second torque transmission device (K2), by means of which the first output element (38 ) of the superposition gear (26) can be connected in a drivingly effective manner to the first output shaft (18) of the gear (10), the first output element ent (32) of the compensating differential (24) is drivingly connected or connectable to the first output shaft (18) of the transmission (10), the second output element (34) of the compensating differential (24) being drivingly connected to the second output shaft (20) of the transmission ( 10) is connected or can be connected, the first output element (38) of the superimposed gear (26) being connected or connectable in a drivingly effective manner to the first output shaft (18) of the transmission (10) and/or the first output element (32) of the differential (24). and wherein the second output element (42) of the superposition gear (26) is drivingly connected or can be connected to the input element (28) of the differential differential (24), characterized in that the second torque transmission device (K2) has a first switching position in which it transmits the first output element (38) of the superposition gear (26) stationary, in particular on a housing element (12), and a second S switching position in which it connects the first output element (38) of the superposition gear (26) with the first output shaft (18) of the gear (10) and/or the first output element (32) of the differential (24) in a drivingly effective manner.

Description

The present invention relates to a transmission for splitting a drive torque between a first and a second shaft or axle of a vehicle, such as a right and left half shaft or, for example, a front and a rear axle of the vehicle as required.

Transmissions of this type for splitting a drive torque between two axles or half-shafts of a vehicle as required are known in principle and usually use at least one friction clutch, by means of which the drive torque can be split between the two shafts in the sense of torque vectoring. However, such friction clutches offer limited variability in the torque distribution and also have limited accuracy or dynamics when setting the desired torque distribution.

Furthermore, the construction costs are not insignificant in such systems. Furthermore, the benefit of such torque vectoring systems is hardly noticeable, especially in the low speed range. Instead, drag losses, which represent sources of losses that increase consumption and emissions, generally predominate in such systems.

Furthermore, such torque vectoring systems are limited to certain driving situations in which the drive torque has to be divided between two shafts as required, without it being possible to switch one of the two shafts torque-free or to decouple it from the drive, as is the case here This may be the case, for example, in less demanding driving situations.

The document US 2007 / 0 123 383 A1 shows, for example, a transmission with a first drive shaft, which is assigned to an electric motor, a first output shaft, which is assigned to a first vehicle shaft, a second output shaft, which is assigned to a second vehicle shaft, a differential with a input element, a first output element and a second output element, a superposition gear with an input element driven by the first drive shaft, a first output element and a second output element, a second torque transmission device, by means of which the first output element of the superposition gear can be connected to the first output shaft of the transmission in a drivingly effective manner, wherein the first output member of the differential differential is drivingly connected or connectable to the first output shaft of the transmission, wherein the second output member of the differential differential is drivingly connected to the second n output shaft of the transmission is or can be connected, the first output element of the superimposed gear being drivingly connected or connectable to the first output shaft of the transmission and/or the first output element of the differential differential, and the second output element of the superimposed gear being drivingly connected or connectable to the input element of the differential differential is.

The pamphlet DE 10 2012 208 678 A1 describes, for example, a drive unit consisting of a primary drive unit, a driven vehicle axle and a multi-stage gearbox. The transmission has primary and secondary transmission input shafts and a transmission output shaft coupled to the driven vehicle axle for transmitting torque. The primary and secondary transmission input shafts each have a clutch for selectively engaging the vehicle's primary drive unit. An electric drive motor for supplying torque to the respectively coupled transmission input shaft is formed with the input shaft.

The invention is based on the object of creating a transmission for splitting a drive torque between a first and a second axle or shaft of a vehicle as required, which does not require lossy friction clutches for splitting the drive torque and which can also be adapted in particular to less demanding driving situations that do not require drive torque splitting.

This object is achieved by a transmission having the features of claim 1.

• eine erste Antriebswelle, die vorzugsweise einem Elektromotor zugeordnet ist;
• eine erste Abtriebswelle, die vorzugsweise einer ersten Fahrzeugwelle (oder Fahrzeugachse) zugeordnet ist;
• eine zweite Abtriebswelle, die vorzugsweise einer zweiten Fahrzeugwelle (oder Fahrzeugachse) zugeordnet ist;
• ein Ausgleichsdifferential mit einem Eingangselement, einem ersten Ausgangselement und einem zweiten Ausgangselement; und
• ein Überlagerungsgetriebe mit einem von der ersten Antriebswelle angetriebenen Eingangselement, einem ersten Ausgangselement und einem zweiten Ausgangselement;

wobei das erste Ausgangselement des Ausgleichsdifferentials antriebswirksam (vorzugsweise drehfest) mit der ersten Abtriebswelle des Getriebes verbunden (oder verbindbar) ist,
wobei das zweite Ausgangselement des Ausgleichsdifferentials antriebswirksam (vorzugsweise drehfest) mit der zweiten Abtriebswelle des Getriebes verbunden (oder verbindbar) ist,
wobei das erste Ausgangselement des Überlagerungsgetriebes antriebswirksam mit der ersten Abtriebswelle des Getriebes und/oder dem ersten Ausgangselement des Ausgleichsdifferentials verbunden oder verbindbar ist; und wobei das zweite Ausgangselement des Überlagerungsgetriebes antriebswirksam mit dem Eingangselement des Ausgleichsdifferentials verbunden oder verbindbar ist.The transmission according to the invention includes:

• a first drive shaft, preferably associated with an electric motor;
• a first output shaft, which is preferably associated with a first vehicle shaft (or vehicle axle);
• a second output shaft, which is preferably associated with a second vehicle shaft (or vehicle axle);
• a ground differential having an input element, a first output element and a second output element; and
• a phasing gear having an input driven by the first drive shaft element, a first output element and a second output element;

wherein the first output element of the differential differential is drivingly connected (preferably non-rotatably) to the first output shaft of the transmission (or can be connected),
wherein the second output element of the differential differential is drivingly connected (preferably non-rotatably) to the second output shaft of the transmission (or can be connected),
wherein the first output element of the superposition gear is or can be connected in a drivingly effective manner to the first output shaft of the gear and/or to the first output element of the differential; and wherein the second output element of the superposition gear is drivingly connected or can be connected to the input element of the differential differential.

Furthermore, the transmission according to the invention has a second torque transmission device, by means of which the first output element of the superimposed transmission can be connected to the first output shaft of the transmission in a drivingly effective manner. The second torque transmission device can have a first switching position, in which it fixes the first output element of the superimposed gearing in a stationary manner, in particular on a housing element, and a second switching position, in which it drives the first output element of the superimposed gearing to the first output shaft of the transmission and/or the connects the first output element of the differential differential,

The differential of the transmission according to the invention serves to a certain extent as a central differential (preferably effective in the transverse direction) with which the drive torque of an internal combustion engine can be transmitted to the two shafts or axles of the vehicle, preferably in equal proportions, independently of the speed of rotation. In contrast, the superposition gear serves as a summation gear, with which, depending on the direction of rotation of the electric motor, an additional (accelerating or decelerating) torque can be applied to one of the two shafts or axles in the sense of torque vectoring, while the drive torque of the other shaft or axle is increased by a corresponding inverse torque is influenced by the differential action of the differential differential.

In order to achieve the desired torque distribution between the two shafts or axles, no friction clutches are required; Rather, a transmission branch is formed by the superposition gear of the transmission according to the invention, which enables an electric motor change of the torque distribution preset by the differential differential. For this purpose, an additional drive torque is superimposed on the preset torque distribution by means of the electric motor, whereby due to the drive-effective connection of the two output elements of the superposition gear with the first output shaft of the gear or the first output element of the differential differential on the one hand and with the input element of the differential differential on the other hand, the drive torque applied by the electric motor can be supported. The rotation of the input element of the differential differential at the current rotational speed (average rotational speed of the two output elements of the differential differential) thus serves as a reference point for torque transmission to the first output element of the differential differential or to the first output shaft of the gearbox. Depending on the direction of rotation of the electric motor, an additional torque can be applied to one of the two shafts or axles of the vehicle (in particular via the first output shaft of the transmission), with the other of the two shafts or axles also being influenced by the differential effect of the differential.

Another advantage is that the electric motor is also superior to conventional implementations using friction clutches in terms of its setting ability, ie the ability to set a desired torque quickly and precisely.

In connection with the invention, it should also be noted that a “torsionally fixed” connection designates a torsionally rigid connection. A "driving" connection means a connection (direct or indirect) between two rotatable elements that are in a fixed rotational relationship to one another (i.e., in a predetermined gear ratio to one another, where i = 1 or i ≠ 1), including a rotationally fixed relationship. When an item is “connectable” or “couptable” to another item, that means a connection that may optionally also be a separable connection (e.g., an indirect connection between the two items via a coupling).

Advantageous embodiments of the transmission according to the invention will now be discussed below, with further advantageous embodiments also being able to result from the dependent claims, the description of the figures and the drawings.

According to an advantageous embodiment, the transmission (and in particular the superimposed transmission) is designed so that, with the same speed of the first output element and the second output element of the differential differential, and/or with the same rotational speed of the first output shaft and the second output shaft of the transmission, the input element of the superimposed transmission stands still. In other words, in this embodiment, the transmission is configured in such a way (and possibly adapted to the other components of the vehicle's drive train with the translations provided there) that when the two shafts or axles of the vehicle are at the same speed, the superposition gear has a zero speed, i.e. the dem Electric motor associated input element of the superposition gear stands still.

Thus, depending on the direction of rotation of the electric motor, an additional torque can be applied to one of the two shafts or axles, independently of the rotational speed or the rotational speed of the two shafts or axles. The design of the electric motor is therefore independent of the maximum speed of the two axles or the vehicle speed; Rather, due to the fact that the electric motor is stationary when both shafts or axles rotate at the same speed, the electric motor can be designed purely on the basis of the desired maximum differential speed between the two shafts or axles and the differential torque. The effect of the electric motor for splitting the torque is therefore independent of the vehicle speed, so that the electric motor does not have to be oversized unnecessarily. Simply by selecting the direction of rotation of the electric motor, it is possible to control whether an accelerating or a decelerating torque is applied to the first output shaft of the transmission.

For this purpose, in particular, the transmission ratio effective between the first output element of the differential differential (or the first output shaft of the transmission) and the first output element of the superimposed gear, as well as the transmission ratio effective between the input element of the differential differential and the second output element of the superimposed gear, and the effective transmission ratio within the superimposed gear Gear ratios can be matched to one another in such a way that the input element of the superposition gearing is stationary at the same speed of the first output element and the second output element of the differential and/or at the same speed of the first output shaft and the second output shaft of the transmission.

According to a further advantageous embodiment, the superposition gear is preferably designed such that the first output element and the second output element of the superposition gear are driven to rotate in opposite directions relative to one another by a rotational movement of the input element. In this way it can easily be achieved that the first output shaft of the transmission (or the first output element of the differential differential) and the input element of the differential differential are always driven in opposite directions by the electric motor. In particular, the transmission (i.e. the superposition gear, the differential and intermediate transmission gears such as offset drives) can be designed so that when the input element of the superposition gear rotates, the first output shaft of the transmission and/or the first output element of the differential on the one hand and the input element of the differential on the other on the other hand are driven in opposite directions.

According to one embodiment, the transmission has a second drive shaft, which is preferably driven by an internal combustion engine, the input element of the differential differential being driveably connectable or connected to the second drive shaft. The transmission can thus be viewed in its entirety as a summation transmission, since both the drive torque of the internal combustion engine and that of the electric motor drive the input element of the differential.

By means of the transmission according to the invention, a vehicle can, for example, be driven purely using the electric motor of the transmission in driving situations with a low need for acceleration, such as when driving on the motorway or driving across country, for which purpose, according to a further embodiment, a first torque transmission device such as a dog clutch is provided by means of which the second drive shaft can be detachably connected to the input element of the differential differential or decoupled from it.

Preferably, the second torque transmission device also has a third switching position in which the first output element of the superposition gear is freely rotatable.

If, for example, by means of the second torque transmission device, the first output element of the superimposed gearing is drivingly connected to the first output shaft of the transmission and / or the first output element of the differential differential, including the second torque transmission device has to be brought into its second switching position, then the basic configuration of the transmission described above is present, in which one of the two axles can be accelerated for the purpose of torque vectoring with the aid of the electric motor and the other axle can be braked by the differential effect of the compensating differential. If, on the other hand, the first output element of the superposition gear is fixed stationary on a housing element by means of the third torque transmission device, for example, the superposition gear acts as a pure transmission stage, by means of which the drive torque of the electric motor is transmitted to the input element of the differential differential only via the second output element of the superposition gear. If the second drive shaft of the transmission is connected to the input element of the differential differential by means of the first torque transmission device, then the transmission acts as a summing transmission, as explained above. If, on the other hand, the second drive shaft is decoupled from the input element of the compensating differential by the first torque transmission device, the vehicle can be driven purely using the electric motor in a first electric gear stage, provided that the first output element of the superimposed gear was fixed to a housing element, for example, by means of the second torque transmission device.

In order to be able to shift a second electrical gear stage in addition to this first electrical gear stage, the transmission comprises, according to a further embodiment, a third torque transmission device which has a first shift position in which it connects the input element of the superimposed gear to rotate together with the second output element of the superimposed gear and one has a second switching position in which the input element of the superimposed gear can be rotated freely by the electric motor. The third torque transmission device preferably also has a third switching position in which it fixes the input element of the superposition gearing in a stationary manner, in particular on a housing element.

In contrast to the first electric gear stage described above, to realize the second electric gear stage, the second torque transmission device has to be transferred to its third switching position, in which the first output element of the superimposed gear is freely rotatable. In contrast, the third torque transmission device is to be transferred to its first switching position to implement the second electric gear stage, in which it connects the input element of the superimposed gear to rotate together with the second output element of the superimposed gear, so that this is locked and the drive torque of the electric motor via the second output element of the superimposed gear is transmitted to the input element of the axle differential without translation by the superimposed gear.

By means of the second and third torque transmission device, two electric gear stages with different speeds or gear ratios can thus be shifted, in which the two gears are in a ratio resulting from the gear ratio of the superimposed gear. Depending on whether the first torque transmission device is engaged or not, the transmission acts as a summation transmission or as a purely electric transmission stage.

According to a further embodiment, it is provided that the differential differential is designed as a cone differential; However, the equalizing differential can also be designed as a ball differential, for example. When the differential is designed as a cone differential, the internal combustion engine drives the carrier of the cone differential carrying the differential gears via the second drive shaft, whereas the two output elements of the differential differential are non-rotatably connected to the bevel gears of the differential, which mesh with the differential gears.

Instead of designing the differential as a bevel gear or ball differential, it would also be possible to design the differential as an epicyclic gear, as is the case according to a further embodiment of the superposition gear, which is preferably a ring gearless planetary gear with pairs of intermeshing planetary gears, which in turn each have an assigned Comb sun gear is formed. For example, the superposition gear can be designed as an epicyclic gear with pairs of meshing planet gears, which are carried by a common planetary carrier, which forms the second output element of the superposition gear. Here, one of the two planetary gears meshes with a sun gear of the superposition gearing, which is driven by the electric motor, whereas the other planetary gear meshes with another sun gear of the superposition gearing, which is non-rotatably connected to the first output element of the superposition gearing.

Although the drive-effective connections between the two output elements of the superposition gear and the first output shaft of the transmission or the input element ment of the axle differential can be formed by belt or chain drives; According to a further embodiment, however, spur gears can also be used for this purpose, by means of which the torque is transmitted between the two output elements of the superposition gear and the first output shaft of the gear or the input element of the differential.

According to yet another embodiment, it is provided that the compensating differential is located outside of a housing of the transmission, in which the electric motor and the superimposed transmission are accommodated. Here, the electric motor is preferably designed as a hollow shaft motor, the rotor of which surrounds the first drive shaft of the transmission. This embodiment offers the advantage that a drive train of a vehicle that already has an axle differential can be converted into a transmission according to the invention, since only the input element of the axle differential driven by the internal combustion engine has to be coupled to the second output element of the superimposed transmission in a drivingly effective manner, which, for example, can be done via a splined connection, which couples the input element of the axle differential with an output gear of an offset drive, which provides a translation between the second output element of the superposition gear and the input element of the axle differential. In this case, all components apart from the already existing axle differential of the transmission can be located within a transmission housing, so that this can be kept available as an add-on unit, by means of which a conventional drive train can be converted to the transmission according to the invention.

According to yet another embodiment, the input element of the differential differential can have a drive gear which meshes both with a gear driven by the second output element of the superposition gear and with a gear which can be driven by the internal combustion engine via the second drive shaft.

The invention also relates to a transmission of the type explained, which is designed as an axle differential for an axle of a vehicle and has the named electric motor, the first drive shaft being drivingly connected or connectable to the electric motor, the first output shaft to a left or right Half-shaft of the vehicle axle is connected or connectable, and the second output shaft is connected or connectable to a right or left half-shaft of the vehicle axle. The axle differential preferably comprises a second drive shaft which can be drivingly connected to an internal combustion engine of the vehicle, the input element of the differential being drivingly connected or connectable to the second drive shaft.

• 1 eine schematische Darstellung eins erfindungsgemäßen Getriebes gemäß einer ersten Ausführungsform in einer Torque-Vectoring-Betriebsart zeigt;
• 2 das Getriebe der ersten Ausführungsform mit abgekoppeltem Verbrennungsmotor in einer Torque-Vectoring-Betriebsart zeigt;
• 3 das Getriebe der ersten Ausführungsform in einer Summierbetriebsart in einer ersten elektrischen Getriebestufe zeigt;
• 4 das Getriebe der ersten Ausführungsform in einer rein elektrischen ersten Getriebestufe zeigt;
• 5 das Getriebe der ersten Ausführungsform in einer Summierbetriebsart in einer zweiten elektrischen Getriebestufe zeigt;
• 6 das Getriebe der ersten Ausführungsform in einer rein elektrischen zweiten Getriebestufe zeigt;
• 7 das Getriebe der ersten Ausführungsform in einem gesperrten Zustand zeigt;
• 8 das Getriebe der ersten Ausführungsform in einer schleppverlustfreien Konfiguration zeigt;
• 9 eine schematische Darstellung eines erfindungsgemäßen Getriebes gemäß einer zweiten Ausführungsform in einer Torque-Vectoring-Betriebsart zeigt, wobei das Getriebe nur über einen elektrischen Antrieb verfügt;
• 10 das Getriebe der zweiten Ausführungsform in einer ersten elektrischen Getriebestufe zeigt;
• 11 das Getriebe der zweiten Ausführungsform in einer zweiten elektrischen Getriebestufe zeigt;
• 12 das Getriebe der zweiten Ausführungsform in einer schleppverlustfreien Konfiguration zeigt;
• 13 eine schematische Darstellung eines erfindungsgemäßen Getriebes gemäß einer dritten Ausführungsform in einer Torque-Vectoring-Betriebsart zeigt;
• 14 das Getriebe der dritten Ausführungsform in einer Summierbetriebsart in einer ersten elektrischen Getriebestufe zeigt;
• 15 das Getriebe der dritten Ausführungsform in einer Summierbetriebsart in einer zweiten elektrischen Getriebestufe zeigt;
• 16 eine schematische Darstellung eines erfindungsgemäßen Getriebes gemäß einer vierten Ausführungsform in einer Torque-Vectoring-Betriebsart zeigt;
• 17 das Getriebe der vierten Ausführungsform in einer Summierbetriebsart in einer ersten elektrischen Getriebestufe zeigt; und
• 18 das Getriebe der vierten Ausführungsform in einer Summierbetriebsart in einer zweiten elektrischen Getriebestufe zeigt.

In the following, the invention is now explained purely by way of example with reference to the accompanying figures, in which:

• 1 shows a schematic representation of a transmission according to the invention according to a first embodiment in a torque vectoring operating mode;
• 2 Figure 12 shows the transmission of the first embodiment with the engine decoupled in a torque vectoring mode;
• 3 shows the transmission of the first embodiment in a summing mode in a first electric transmission stage;
• 4 shows the transmission of the first embodiment in a purely electric first transmission stage;
• 5 shows the transmission of the first embodiment in a summing mode in a second electric transmission stage;
• 6 shows the transmission of the first embodiment in a purely electric second transmission stage;
• 7 shows the transmission of the first embodiment in a locked state;
• 8th Figure 12 shows the transmission of the first embodiment in a no-drag configuration;
• 9 shows a schematic representation of a transmission according to the invention according to a second embodiment in a torque vectoring operating mode, the transmission only having an electric drive;
• 10 shows the transmission of the second embodiment in a first electric transmission stage;
• 11 shows the transmission of the second embodiment in a second electric transmission stage;
• 12 Figure 12 shows the transmission of the second embodiment in a no-drag configuration;
• 13 shows a schematic representation of a transmission according to the invention according to a third embodiment in a torque vectoring operating mode;
• 14 shows the transmission of the third embodiment in a summing mode in a first electric transmission stage;
• 15 shows the transmission of the third embodiment in a summing mode in a second electric transmission stage;
• 16 shows a schematic representation of a transmission according to the invention according to a fourth embodiment in a torque vectoring operating mode;
• 17 shows the transmission of the fourth embodiment in a summing mode in a first electric transmission stage; and
• 18 shows the transmission of the fourth embodiment in a summing mode in a second electric transmission stage.

the 1 shows a basic configuration of the transmission 10 according to the invention, from which all other embodiments can be derived, which is why the description of the other embodiments according to the 2 until 18 only the essential distinguishing features compared to the basic configuration are discussed. However, it should be noted that not all of the clutches K1 to K3 explained below are required.

That in the 1 Transmission 10 shown schematically can be provided, for example, as an axle differential on the rear axle of a vehicle. The transmission 10 has a transmission housing 12 and has a first drive shaft 14, a second drive shaft 16, a first output shaft 18 and a second output shaft 20. The first drive shaft 14 is assigned here to an electric motor 22, through which the first drive shaft 14 has a drive torque can be charged. The second drive shaft 16 is assigned to an internal combustion engine, not shown here, from which the second drive shaft 16 can also be subjected to a drive torque, for example via a cardan shaft (not shown) aligned in the longitudinal direction of the vehicle.

The first output shaft 18 of the transmission 10 can be drivingly coupled to a first shaft of the vehicle, which can be, for example, a left half-shaft of the rear axle of the vehicle. Likewise, the second output shaft 20 of the transmission 10 can be coupled to a second shaft of the vehicle, which can be, for example, a right half-shaft of the rear axle of the vehicle. In such a configuration, the two output shafts 18, 20 are aligned in the transverse direction of the vehicle. However, the vehicle shafts driven by the two output shafts 18, 20 do not necessarily have to be right and left half-shafts of the vehicle; Rather, the two output shafts 18, 20 of the transmission 10 can also be used, for example, to drive a front and a rear axle of the vehicle, as a result of which all-wheel drive can be implemented. In this case, the transmission 10 is configured as a longitudinal differential, with the two output shafts 18, 20 being aligned in the longitudinal direction of the vehicle and being able to be connected to the respective axle differentials via cardan shafts, for example.

Transmission 10 also includes a differential differential 24, embodied here, for example, as a bevel differential, and a superposition gear 26, embodied, for example, as an epicyclic gear. The input element 28 of the compensating differential 24 can be driven by the internal combustion engine via the second drive shaft 16, as will be explained below. Furthermore, differential differential 24 includes a first output element 32 in the form of a bevel gear and a second output element 34, likewise in the form of a bevel gear, with the two bevel gears meshing with differential gears 30, so that by means of differential differential 24, a drive torque transmitted thereto is distributed in equal proportions to the two output elements 32, 34 can be transmitted in the form of the two bevel gears.

The superimposed gear 26 also includes an input element 36 in the form of a first sun wheel, which can be driven by the electric motor 22 via the first drive shaft 14 . The superposition gear 26 also includes a first output element 38 in the form of a second sun gear and a second output element 42 in the form of a planet carrier. The first sun gear, which acts as an input element 36, meshes with a first planetary gear 44, which is rotatably mounted on the planetary carrier 42. This first planet wheel 44 in turn meshes with a second planet wheel 46, which is also mounted on the planet carrier 42 and meshes with the first output element 38, which is designed as a second sun wheel. Even if it is not shown here, further pairs of meshing planet gears 44, 46 are mounted on the planet carrier 42, as is usually the case with such an epicyclic gear without a ring gear. The superposition gear 26 thus also forms a (here asymmetrical) differential gear, since a drive torque introduced via the input element 36 is distributed to the first output element 38 and the second output element 42 . The superposition gear 26 could alternatively also by a different type of planetary wheel differential can be formed, for example with a ring gear.

Again 1 can also be seen, in the illustrated embodiment of the transmission 10, the first output element 32 of the differential differential 24 in the form of the first bevel gear is non-rotatably connected to the first output shaft 18 of the transmission 10. In a corresponding manner, the second output element 34 of the differential differential 24 in the form of the second bevel gear is connected to the second output shaft 20 of the transmission 10 in a rotationally fixed manner.

Furthermore, the compensating differential 24 and the superposition gear 26 are coupled to one another in a drivingly effective manner via two offset drives 48, 50, which are formed here by two spur gears in the form of two meshing spur gears. As an alternative to this, the offset drives 48, 50 can also be formed, for example, by belt or chain drives. The first offset drive 48 thus forms a first gear track, via which the first output element 38 of the superposition gear 26 can be connected in a drivingly effective manner to the first output shaft 18 of the gear 10 or to the first output element 32 of the differential differential 24, which takes place by engaging a dog clutch. which is referred to here as the second torque transmission device K2, which will be discussed in more detail later. In contrast, the second output element 42 of the differential differential 26 via the second gear track in the form of the second offset drive 50 is drivingly connected to the input element 28 of the differential differential 24 in the form of its carrier.

The transmission of the two offset drives 48, 50 and the transmission ratio of the superimposed gear 26 are designed in the transmission 10 according to the invention so that the input element 36 of the superimposed gear 24 is stationary (zero speed) when both output shafts 18, 20 rotate at the same speed.

Formulated even more generally are the effective transmission ratio between the first output element 32 of the differential differential 24 (or the first output shaft 18) and the first output element 38 of the superposition gear 26 (here: first offset drive 48), as well as that between the input element 28 of the differential differential 24 and the second output element 42 of the superposition gear 26 effective transmission ratio (here: second offset drive 50), and the effective transmission ratios within the superposition gear 26 (here: between the input element 36, the first planetary gear 44, the second planetary gear 46 and the second output element 42) are adapted to one another in this way that at the same speed of the first output element 32 and the input element 28 of the differential differential 24 and / or at the same speed of the two output shafts 18, 20 of the transmission 10, the input element 36 of the superposition gear 26 is stationary. At the same time, the superimposed gear 26 is designed such that the first output element 38 and the second output element 42 of the superimposed gear 26 are driven to rotate in opposite directions relative to one another by a rotary movement of the input element 36 (differential effect).

The drive torque of the electric motor 22 can be transmitted via the second offset drive 50 to the input element 28 of the differential differential 24 , which is likewise driven by the internal combustion engine via the second drive shaft 16 . For this purpose, the input element 28 in the form of the carrier of the compensating differential 24 is surrounded by a basket 25 which is mounted on the housing 12 and is driven by the second drive shaft 16 via a bevel gear bevel gear 31 . The torque is transmitted from the basket 25 to the input element 28 of the differential differential 24 via a first torque transmission device K1 in the form of a dog clutch, by means of which a driving connection can be established between the second drive shaft 16 and the input element 28 of the differential differential 24, for which purpose the basket 25 in the left position of the first torque transmission device K1 is connected to the input element 28 in a torque-proof manner.

In addition, the transmission 10 has a third torque transmission device K3, also in the form of a claw clutch, which has three shift positions, which will be discussed in more detail below.

If it is now desired to apply an additional drive torque to one of the two output shafts 18, 20 and thereby indirectly (due to the interaction via the compensating differential 24) to apply a corresponding braking torque to the other output shaft 20, 18, the input element 36 in the form of the first sun gear of the Superposition gear 26 driven by the electric motor 22 in a first direction of rotation. The torque of the electric motor 22 is in this case transmitted via the first offset drive 48 to the first output shaft 18 of the transmission 10 if the second torque transmission device K2 is in its in 1 shown shift position is in which they drive the first output element 38 of the superposition gear 26 with the first output shaft 18 of the transmission 10 and the ers th output element 32 of the differential differential 24 connects. The electric motor 22 can be supported here via the superposition gear 26 and the second offset drive 50 on the input element 28 of the differential differential 24, i.e. the rotation of the input element 28 of the differential differential 24 at the current speed (average speed of the two output shafts 18, 20) serves as a reference point for torque transmission to the first output shaft 18 of the transmission 10.

The torque transmitted via the first offset drive 48 to the first output shaft 18 is transmitted to the second output shaft 20 by the differential effect of the compensating differential 24 with a negative sign or in the opposite direction of rotation. Thus, for example, the first output shaft 18 can be accelerated in the sense of torque vectoring relative to the second output shaft 20 and the second output shaft 20 can be braked accordingly. If, on the other hand, it is desired to brake the first output shaft 18 and to accelerate the second output shaft 20, then only the electric motor 22 has to be driven in an opposite direction for this purpose.

Due to the explained presetting of a zero speed of the input element of the superposition gear 26 (first drive shaft 14 driven by the electric motor 22), a torque vectoring function can thus be implemented independently of the speed of the two output shafts 18, 20 or the basic speed of the vehicle, with the additional torque , which can be impressed on the respective shaft 18, 20 with the aid of the electric motor 22, is independent of the vehicle speed. The electric motor 22 can thus be designed purely on the basis of the desired maximum differential speed between the two output shafts 18, 20 and the differential torque.

Based on 1 it can be seen that the torque transmission devices K1, K2 and K3 are not required to implement the explained torque vectoring operating mode alone. Instead, the basket 25 could also be permanently non-rotatably connected to the input element 28 of the differential differential 24, and the first output element 38 of the superimposed gear 26 could be permanently connected to the first output shaft 18 of the transmission 10 or the first output element 32 of the differential differential 24 in a drivingly effective manner.

When previously referring to the 1 In the torque vectoring mode described, the first torque-transmitting mechanism K1 was engaged in order to be able to transmit the drive torque of the internal combustion engine from the basket 25 to the carrier of the differential differential 24 serving as the input element 28 . The drive torque of the internal combustion engine transmitted in this way to the two output shafts 18, 20 can thus be modified by the electric motor 22 in accordance with the previously described torque vectoring in order, for example, to drive the outside wheel more than the inside wheel when cornering.

According to the presentation of 2 However, the internal combustion engine can also be decoupled from the transmission 10 by means of the first torque transmission device K1 (“disconnect”), so that the two output shafts 18, 20 are driven solely by the electric motor 22. By decoupling the internal combustion engine from the transmission 10 by means of the first torque transmission device K1, it is thus possible to switch to a purely electric drive of the two output shafts 18, 20, with one vehicle axle being driven by the internal combustion engine, for example, while the two half-shafts of the other vehicle axle are in the form of the Both output shafts 18, 20 are driven by the electric motor 22 with the possibility of torque vectoring.

According to 3 the transmission 10 is in a summation mode in which an additional drive torque is superimposed by the electric motor 22 on the drive torque of the internal combustion engine (“e-push/e-pull”). For this purpose, the first output element 38 of the superposition gear 26 is fixed to the housing with the aid of the second torque transmission device K2. In this case, the drive torque of the electric motor 22, reduced by the superposition gear 26, is transmitted by the second offset drive 50 to the input element 28 of the differential differential 24, where it is superimposed on the drive torque of the internal combustion engine.

If the first output element 38 of the superposition gear 26 is fixed, according to FIG 3 additionally the first torque transmission device K1 disengaged, according to 4 the transmission 10 can be operated in a purely electric mode by the electric motor 22 in a first purely electric gear stage.

In contrast to 3 located at the in the 5 illustrated summation mode of the transmission 10, the second torque transmission device K2 in a neutral position in which the first output element 38 of the superposition gear 26 is freely rotatable. In contrast, however, the third torque transmission device K3 is in its first switching position, in which it controls the input element 36 of the superimposed transmission BES 26 for common rotation with the second output element 42 of the superposition gear 26 connects. The superimposed gear 26 is thus blocked, so that the drive torque of the electric motor 22 is transmitted without translation by the superimposed gear 26 via the second offset drive 50 to the input element 28 of the differential differential 24, where it is superimposed on the drive torque of the internal combustion engine.

In order to be able to realize a second, purely electric gear stage, the first torque transmission device K1 according to FIG 6 be disengaged in turn, so that the two output shafts 18, 20 are driven purely electrically by the electric motor 22.

To use the transmission 10 according to the invention 7 In order to be able to implement the function of a parking brake, the basket 25 is coupled in a torque-proof manner to the input element 28 of the compensating differential 24 by means of the first torque transmission device K1. In addition, it must be ensured that the second torque transmission device K2 is in its second switching position, in which it effectively connects the first output element 38 of the superposition gear 26 to the first output shaft 18 of the gear 10 . Furthermore, the third torque transmission device K3 must be transferred to its third switching position, in which the input element 36 of the superposition gear 26 is stationary. The transmission 10 thus has no degree of freedom of rotation between the first input shaft 14 on the one hand and the second input shaft 16 and the two output shafts 18, 20 on the other hand, so that a vehicle equipped with the transmission 10 cannot unintentionally roll away.

the 8th shows the transmission 10 in a configuration without drag losses, in which the three torque transmission devices K1, K2 and K3 are each in a neutral position, so that no torque transmission is possible via them. In this way, drag and rolling friction losses within the transmission 10 can be reduced, as may be desirable, for example, if the vehicle is to be driven solely using the internal combustion engine.

This in 9 Transmission 10 shown differs from that of 1 only in that the transmission does not have a second output shaft via which the two output shafts 16, 18 can be driven by means of an internal combustion engine. This transmission 10 can be used in particular as a purely electric vehicle axle. Otherwise corresponds to in the 9 shown switching position of the transmission 10 and its operation with reference to the 1 Torque vectoring mode described, which is why in this regard to the corresponding statements on 1 is referenced.

According to the 10 and 11 is that to 9 explained transmission 10 according to the 4 and 6 in a purely electric operating mode with two different gear stages. Accordingly, the corresponding statements on the 4 and 6 referred.

According to 12 assigns that 9 Explained transmission 10 in turn has a drag-loss-free configuration in which the two torque transmission devices K2 and K3 are in their neutral position so that no torque can be transmitted.

At the in 13 illustrated embodiment is the differential differential 24 outside of the housing 12 of the transmission 10 in which the electric motor 22 and the superposition gear 26 are housed. In this embodiment, the electric motor 22 is designed as a hollow shaft motor which surrounds the first drive shaft 14 coaxially. Here, the first drive shaft 14 is designed as a hollow shaft, so that the first output shaft 18 of the transmission 10 can extend through it.

Here, too, the input element 36 of the superposition gear 26 is in turn driven by the electric motor 22 via the first drive shaft 14, specifically via a third offset drive 52, which is again designed here as a spur gear.

As in the embodiment of 1 Here again, the first output element 38 of the superposition gear 26 in the form of the second sun gear is connected via a first offset drive 48 to the first output shaft 14 of the transmission 10 or the first output element 32 of the differential differential 24, and the second output element 42 of the superposition gear 26 is also in the form of the carrier is connected via a second offset drive 50 to the input element 28 in the form of the carrier of the differential differential 24 . In particular, the carrier is connected to the driven gear wheel 58 of the second offset drive 50 via a serrated connection 60, as a result of which the second offset drive 50 can easily be retrofitted to the differential differential 24 in order to convert the drive train of a vehicle that already has an axle differential to an inventive to convert the gearbox.

Furthermore, the input element 28 of the compensating differential 24 here has a than Spur gear trained drive wheel 54, via which the input element 28 can in turn be driven by an internal combustion engine.

In this respect, although the structural design of the transmission 10 differs according to the 13 from the the 1 ; in functional and kinematic terms corresponds to the transmission 10 of 13 however the the 1 , which is why with regard to the torque vectoring function, in turn, refer to the corresponding statements on 1 is referenced.

In contrast to 13 the gear 10 is in the 14 in its summing mode in a first electrical gear stage, for which purpose the first output element 38 of the superposition gear 26 was firmly connected to the gear housing 12 using the second torque transmission device K2.

In the 15 transmission 10 is also in a summation mode, but here the superposition gear 26 is locked by means of the third torque transmission device K3 and the second torque transmission device K2 is in a neutral position, so that the drive torque from the electric motor 22 without translation by the superimposition gear 26 via the two offset drives 48, 52 can be transferred to the input element 28 of the differential differential 24, which is of the type with reference to the 5 corresponds to the summation mode described.

Also in the embodiment according to 16 the drive torque of the internal combustion engine is in turn transmitted to the input element 28 of the differential differential 24 via a drive wheel 54 provided on the input element 28 of the differential differential. This drive gear 54 meshes equally with a gear 56 driven by the second output element 42 of the superposition gear 26, so that this drive gear 54 and the gear 56 in turn form a second offset drive 50, via which the drive torque from the electric motor 22 from the second output element 42 of the superposition gear 26 can be transmitted to the input element 28 of the differential differential 24. The first output element 38 of the superimposed gear 26 is in turn drivingly connected to the first output shaft 18 of the gear 10 via a first offset drive 48 or can be releasably connected by means of a second torque transmission device K2, so that with reference to 16 Transmission 10 described in structural terms of the 1 differs; in functional and kinematic terms corresponds to the transmission 10 of 16 however, again the the 1 , which is why regarding the in the 16 illustrated torque vectoring function turn to the corresponding explanations 1 is referenced.

In contrast to 16 the gearbox is in the 17 in its summing mode in a first electrical gear stage, for which purpose the first output element 38 of the superposition gear 26 was firmly connected to the gear housing 12 using the second torque transmission device K2.

In the 18 transmission 10 is also in a summation mode, but here the superposition gear 26 is locked by means of the third torque transmission device K3 and the second torque transmission device K2 is in a neutral position, so that the drive torque from the electric motor 22 without translation by the superimposition gear 26 via the two offset drives 48, 52 can be transferred to the input element 28 of the differential differential 24, which is of the type with reference to the 5 corresponds to the summation mode described.

Reference List

10

transmission

12

gear case

14

first driveshaft

16

second driveshaft

18

first output shaft

20

second output shaft

22

electric motor

24

balancing differential

25

basket

26

superposition gear

28

Input element of 24

30

balance wheels

31

Bevel gear box

32

first output element of 24

34

second output element of 24

36

Input element of 26

38

first output element of 26

42

second output element of 26

44

first planet wheel

46

second planet gear

48

first offset drive

50

second offset drive

52

third displacement drive

54

drive wheel

56

gear

58

output gear

60

serrated connection

K1

first torque transfer device

K2

second torque transfer device

K3

third torque transfer device

Claims (14)

Transmission (10) for splitting a drive torque between a first and a second shaft or axle of a vehicle as required, comprising: - a first input shaft (14), which is preferably assigned to an electric motor (22), - a first output shaft (18), which is preferably assigned to a first vehicle shaft, - a second output shaft (20), which is preferably assigned to a second vehicle shaft, - a differential (24) with an input element (28), a first output element (32) and a second output element (34), - a superposition gear (26) with an input element (36) driven by the first drive shaft (14), a first output element (38) and a second output element (42) and - a second torque transmission device (K2), by means of which the first output element (38 ) of the superposition gear (26) can be connected in a drivingly effective manner to the first output shaft (18) of the gear (10), the first output gselement (32) of the compensating differential (24) drivingly connected or connectable to the first output shaft (18) of the transmission (10), wherein the second output element (34) of the compensating differential (24) drivingly connected to the second output shaft (20) of the transmission ( 10) is connected or can be connected, the first output element (38) of the superimposed gear (26) being connected or connectable in a drivingly effective manner to the first output shaft (18) of the transmission (10) and/or the first output element (32) of the differential (24). and wherein the second output element (42) of the superposition gear (26) is drivingly connected or can be connected to the input element (28) of the differential (24), characterized in that the second torque transmission device (K2) has a first switching position in which it transmits the first output element (38) of the superposition gear (26) stationary, in particular on a housing element (12), and a z has a wide switching position in which it connects the first output element (38) of the superposition gear (26) with the first output shaft (18) of the gear (10) and/or the first output element (32) of the differential (24) in a drivingly effective manner. gear after claim 1 , characterized in that the transmission (10) is designed such that when the speed of the first output element (32) and the second output element (34) of the differential differential (24) and/or when the speed of the first output shaft (18) and the second output shaft (20) of the transmission (10) the input element (36) of the superposition gear (26) is stationary. gear after claim 1 or 2 , characterized in that the superimposed gear (26) is designed such that the first output element (38) and the second output element (42) of the superimposed gear (26) are driven to rotate in opposite directions relative to one another by a rotational movement of the input element (36). Transmission according to at least one of the preceding claims, characterized in that a second drive shaft (16) is provided, which is preferably assigned to an internal combustion engine, the input element (28) of the compensating differential (24) being drivingly connected or connectable to the second drive shaft (16). is. gear after claim 4 , characterized in that a first torque transmission device (K1) is provided, by means of which the second drive shaft (16) is drivingly connected to the input element (28) of the differential (24). gear after claim 1 , characterized in that the second torque transmission device (K2) also has a third switching position in which the first output element (38) of the superposition gear (26) is freely rotatable. Transmission according to at least one of the preceding claims, characterized in that a third torque transmission device (K3) is provided which has a first switching position in which it activates the input element (36) of the superposition gear (26) for common rotation with the second output element (42) of the Superposition gear (26) connects, and has a second switching position in which the input element (36) of the superposition gear (26) can be rotated freely by the electric motor (22). gear after claim 7 , characterized in that the third torque transmission device (K3) also has a third switching position in which the input element (36) of the superposition gear (26) is stationary, in particular on a housing element (12), can be fixed. Transmission according to at least one of the preceding claims, characterized in that the compensating differential (24) is designed as a bevel gear differential. Gear according to at least one of the preceding claims, characterized in that the superposition gear (26) is designed as an epicyclic gear, in particular as a planetary gear without a ring gear with pairs of intermeshing planet wheels (44, 46). Gear according to at least one of the preceding claims, characterized in that the first output element (38) of the superposition gear (26) is connected indirectly via a first offset drive (48) to the first output shaft (18) and/or the first output element (32) of the differential differential ( 24) is connected or connectable. Transmission according to at least one of the preceding claims, characterized in that the second output element (42) of the superimposed transmission (26) is drivingly coupled to the input element (28) of the differential (24) via a second offset drive (50). Transmission according to at least one of the preceding claims, characterized in that the compensating differential (24) is located outside a housing (12) of the transmission (10) in which the electric motor (22) and the superposition gear (26) are accommodated. Transmission according to at least one of the preceding claims, characterized in that the input element (28) of the compensating differential (24) has a drive gear (54) which is driven by a gear (56) driven by the second output element (42) of the superposition gear (26). and meshes with a gear that can be driven by the second drive shaft (16).

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