DE102021208061A1 - electric vehicle transmission - Google Patents

Abstract

The invention relates to an electric vehicle transmission (7), comprising a drive shaft (11) which is intended for connection to at least one electric machine (6), an output shaft (12) and a planetary gear set system (13), the planetary gear set system having a first shaft (14 ), a second shaft (15), a third shaft (16) and a fourth shaft (17) are assigned, of which the third shaft (16) is fixed and the fourth shaft (17) is non-rotatably connected to the output shaft (12). . In addition, a first switching element (A) and a second switching element (B) are provided, of which the first switching element (A) in an actuated state connects the drive shaft (11) and the first shaft (14) to one another in a rotationally fixed manner, whereas the second switching element ( B) brings about a non-rotatable connection between the drive shaft (11) and the second shaft (15) in an actuated state. In order to achieve an axially compact design of the electric vehicle transmission (7), the drive shaft (11) is formed at least in sections by a hollow shaft (31), the first shifting element (A) and the second shifting element (B) being axially level and radially on the inside of one Connection area (32) of this hollow shaft (31) are placed, which serves to establish the connection to the at least one electric machine (6) radially on the outside.

Description

The invention relates to an electric vehicle transmission, comprising a drive shaft, which is provided for connection to at least one electric machine, an output shaft and a planetary gear set system, with the planetary gear set system being assigned a first shaft, a second shaft, a third shaft and a fourth shaft, of which the third shaft is fixed and the fourth shaft is connected to the output shaft in a rotationally fixed manner, with a first switching element and a second switching element being provided, of which the first switching element in an actuated state connects the input shaft and the first shaft to one another in a rotationally fixed manner, whereas the second switching element in in an actuated state, brings about a non-rotatable connection between the drive shaft and the second shaft. Furthermore, the invention relates to a drive unit with an aforementioned electric vehicle transmission and an electric vehicle.

In electric vehicles, drive units are known which are often composed of at least one electric machine and a downstream multi-speed gearbox. Different gears can be shifted in the respective multi-speed transmission in order to convert a drive movement of the at least one electric machine with different gear ratios and thereby achieve higher top speeds of the electric vehicle in interaction with the electric machine and/or to operate the electric machine in a range with a high level of efficiency to allow.

So reveals the DE 10 2018 129 175 A1 a drive unit for an electric vehicle, an electric vehicle transmission being connected downstream of one or more electric machines in this drive unit. The electric vehicle transmission includes in a variant of DE 10 2018 129 175 A1 in addition to a drive shaft and an output shaft lying coaxially thereto, a planetary gear set system with four shafts, of which a first shaft is non-rotatably connected to a first sun gear and a second shaft is non-rotatably connected to a second sun gear of the planetary gear set system, while a third shaft is non-rotatably connected to a ring gear and a fourth shaft rotatably connected to a planet carrier of the planetary gear set system.

The planetary carrier supports at least one stepped planetary gear, which is in meshing engagement on a first toothing with the first sun gear and on a second toothing with the second sun gear and the ring gear. The third shaft of the planetary gear set system is permanently fixed so that the ring gear is also constantly prevented from rotating. In contrast, the fourth shaft is non-rotatably connected to the output shaft, which is followed by a further, stepped planetary gear set. In addition, two shifting elements are also provided, of which the first shifting element connects the first shaft to the drive shaft in a rotationally fixed manner when actuated, while the second shifting element causes a rotationally fixed connection between the drive shaft and the second shaft when actuated. The two shifting elements are each axially level with and radially inward of the respective sun gear. A connection of the drive shaft to the at least one electric machine is also realized on the end face of the drive shaft.

Based on the prior art described above, it is now the object of the present invention to create an electric vehicle transmission in which different transmission ratios for the integration of at least one electric machine can be realized and which is also characterized by an axially compact design.

This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow each specify advantageous developments of the invention. In addition, claims 11 to 13 each relate to a drive unit for an electric vehicle with an electric vehicle transmission according to the invention. Finally, claim 14 relates to an electric vehicle with a drive unit.

According to the invention, an electric vehicle transmission comprises an input shaft, which is provided for connection to at least one electric machine, an output shaft and a planetary gear set system. A first shaft, a second shaft, a third shaft and a fourth shaft are assigned to the planetary gear set system, of which the third shaft is fixed and the fourth shaft is non-rotatably connected to the output shaft. Furthermore, a first switching element and a second switching element are provided, of which the first switching element in an actuated state connects the drive shaft and the first shaft in a rotationally fixed manner, whereas the second switching element causes a rotationally fixed connection between the drive shaft and the second shaft in an actuated state .

In the context of the invention, a “shaft” is to be understood as meaning a rotatable component of the transmission, via which a power flow can be guided between components, if necessary with simultaneous actuation of a corresponding shifting element. The respective shaft components can be axial or radial or both axial and connect radially. The respective shaft can also be present as an intermediate piece, via which a respective component of the electric vehicle transmission is connected radially, for example.

In the context of the invention, “axial” means an orientation in the direction of a longitudinal central axis of the transmission, parallel to which the axes of rotation of the shafts of the transmission are arranged. “Radial” is then to be understood as meaning an orientation in the diameter direction of a respective component of the transmission.

In the electric vehicle transmission according to the invention, the drive shaft is intended to establish a drive-side connection to at least one electric machine, which is connected upstream of the electric vehicle transmission in a built-in state in a drive train of an electric vehicle in the power flow. For this purpose, the drive shaft is equipped in particular with a connection area, on which a coupling of the drive shaft with a respective rotor of the at least one electric machine can be formed. Within the scope of the invention, at least one further transmission stage, such as a spur gear stage and/or a planetary stage, can be provided between the drive shaft and each rotor of the electric machine, via which a pre-transmission of a rotary movement of the rotor of the electric machine onto the drive shaft is representable. Particularly preferably, however, the rotor of the electric machine is rigidly connected to the drive shaft of the electric vehicle transmission according to the invention, so that the rotor and the drive shaft run at the same speed during operation.

In the electric vehicle transmission according to the invention, the input shaft and the output shaft are in particular arranged coaxially with one another, with the planetary gear set system also preferably being placed coaxially with the input shaft and the output shaft. This makes it possible to realize a particularly compact design of the electric vehicle transmission in the radial direction.

The electric vehicle transmission according to the invention also has two shifting elements, with different transmission ratios between the input shaft and the output shaft preferably being able to be achieved by their selective actuation. In particular, precisely two shifting elements are provided in the electric vehicle transmission according to the invention.

Four shafts are assigned to the planetary gear set system, these shafts being arranged in particular coaxially to one another and more preferably lying coaxially to the input shaft and the output shaft. For this purpose, the shafts can each be designed as a solid shaft, as a hollow shaft or in sections as a solid shaft and in sections as a hollow shaft.

Of the shafts, the first shaft can be connected in a rotationally fixed manner to the drive shaft by closing the first switching element, with which the second shaft can also be connected in a rotationally fixed manner by actuating the second switching element. In contrast, the third shaft is permanently fixed, the third shaft preferably being non-rotatably connected to a permanently stationary component of the transmission, which can be a housing, a housing part or a component non-rotatably connected thereto. It is also conceivable within the scope of the invention to design the third shaft in one piece with the permanently stationary component or to connect it rigidly to the permanently stationary component. Finally, the fourth shaft is non-rotatably connected to the output shaft, wherein the fourth shaft and the output shaft can be present as separate shafts that are rigidly connected to one another and accordingly always rotate at the same speed. Alternatively, and particularly preferably, the fourth shaft and the output shaft could also be designed in one piece, i.e. formed by a single, common shaft.

The invention now includes the technical teaching that the drive shaft is formed at least in sections by a hollow shaft. The first shifting element and the second shifting element are placed axially at least overlapping and radially on the inside of a connection area of this hollow shaft, which serves to connect the drive shaft to the at least one electric machine radially on the outside. In other words, the drive shaft of the electric vehicle transmission according to the invention has a hollow shaft at least as a section, which means within the scope of the invention that the drive shaft can either be designed completely as a hollow shaft or has at least one hollow shaft section. The first and second shifting elements are then arranged radially on the inside of this hollow shaft, with the two shifting elements at least overlapping axially with a region of the hollow shaft on which the connection to the at least one electric machine is established when the electric vehicle transmission is installed.

Such a configuration of an electric vehicle transmission has the advantage that the connection of the drive shaft to the at least one electric machine and the respective non-rotatable connection of the drive shaft to either the first shaft or the second shaft of the planetary gear set system is carried out in an axial area via the two switching elements, which means that the axial installation space of the electric vehicle transmission can be significantly reduced. Because this allows a nested structure to be implemented, in which a non-rotatable connection of the drive shaft to the first shaft or the second shaft can be made on an inner circumference of the hollow shaft, while axially in the same area on an outer circumference of the hollow shaft the connection to the at least one Electric machine is made. In combination with at least one electric machine, a drive unit can also be implemented that has an axially compact structure.

The fact that the first shifting element and the second shifting element are placed axially "at least overlapping" with the connection area means, within the meaning of the invention, that the two shifting elements are provided radially on the inside of the hollow shaft in an area which axially overlaps at least with the connection area. Particularly preferably, the area in which the two switching elements are arranged lies axially but completely within the connection area.

The two switching elements are placed radially on the inside of the hollow shaft, with the individual switching element connecting the hollow shaft on an inner circumference to the respective shaft in a rotationally fixed manner when actuated. The connection area can make up an axial section of the hollow shaft, but the connection area can also extend essentially axially over the entire length of the hollow shaft on the outer circumference.

According to one embodiment of the invention, the first shifting element and the second shifting element are designed as positive-locking shifting elements, and they are preferably present as unsynchronized claw shifting elements. Advantageously, the individual switching element can be designed with a simple structure and thus also low manufacturing costs, the individual switching element also causing no or almost no drag losses even in an open state, which improves the efficiency of the electric vehicle transmission. Since speeds on the respective shifting element can also be synchronized in a simple manner prior to actuation via the at least one electric machine, changes between transmission ratios can be carried out without any problems despite the shifting elements being designed as unsynchronized shifting elements. As an alternative to an embodiment as unsynchronized claw shifting elements, the two shifting elements can also be designed as blocking synchronizations. As a further alternative, one or both switching elements can also be present as non-positive switching elements, in particular as multi-plate switching elements. In the latter case, a change between transmission ratios can also be represented under load.

In a further development of the aforementioned embodiment, the first switching element and the second switching element are part of a switching device which has an axially displaceable actuating element. Depending on its axial position, the actuating element brings about the actuated state of the first switching element and the actuated state of the second switching element. As a result, the two switching elements can be actuated alternately via a common actuating element, as a result of which the two switching elements can be arranged in a particularly compact manner and the number of components can also be reduced. The latter thus also reduces the manufacturing costs of the electric vehicle transmission according to the invention. Particularly preferably, in addition to a first switching position, in which the first switching element is actuated, and a second switching position, in which the second switching element is actuated, the actuating element can also be positioned in a neutral position, in which neither of the two switching elements is transferred to its actuated state is. In this way, the drive shaft can also be decoupled from the output shaft.

More preferably, the actuating element is designed as a sliding sleeve, the sliding sleeve being equipped on an outer circumference with a first carrier toothing, via which the sliding sleeve is guided in an axially displaceable manner on a carrier toothing of the hollow shaft. In addition, the sliding sleeve is provided on an inner circumference with a second carrier toothing, on which the sliding sleeve comes into meshing with a carrier toothing of the first shaft during axial displacement and in a second switching position meshes with a carrier toothing of the second shaft. In particular, the first shaft and the second shaft are each guided axially into the hollow shaft with shaft ends, with the respective driving toothing for the toothed engagement with the sliding sleeve being formed on the shaft ends. As a result, a suitable, compact design of a switching device can be implemented.

According to one possible embodiment of the invention, the actuating element is coupled to a setting actuator, via which an axial displacement of the actuating element can be initiated. The control actuator is in particular an electromechanical control actuator, in which the power supply a corresponding mechanical adjustment movement for the axial displacement of the actuating element is generated.

In a further development of the aforementioned configuration option, the setting actuator is placed axially on a side of the drive shaft facing away from the first and second shaft, the coupling of the setting actuator to the actuating element being completed via a coupling rod. As a result, the setting actuator can be arranged at a distance from the actuating element without any problems, with this also making it possible to place the setting actuator outside of a housing of the electric vehicle transmission.

The coupling rod is particularly preferably designed as a toothed rack at least at one end facing the setting actuator, with a toothing of the toothed rack being in meshing engagement with a spur gear which is placed non-rotatably on a setting shaft of the setting actuator lying transversely to the coupling rod. With this structure, a rotational adjustment movement of the adjustment actuator can be reliably converted into a translatory, axial sliding movement of the coupling rod and thus also of the actuating element. As an alternative to this, the setting actuator could also generate an axial setting movement directly and transmit this to the actuating element either directly or via an intermediate coupling rod. In addition, the positioning actuator could also be arranged parallel to the coupling rod, which is designed as a toothed rack at the end, in which case a worm wheel, for example, could then be arranged on a positioning shaft of the positioning actuator.

According to an advantageous embodiment of the invention, the planetary gear set system has a first sun gear, a second sun gear, a ring gear and a planet carrier, which guides at least one stepped planet in a rotatably mounted manner. The at least one stepped planetary gear meshes with the first sun gear on a first gearing and with the second sun gear and the ring gear on a second gearing. The first sun gear is non-rotatably connected to the first shaft, the second sun gear is non-rotatably connected to the second shaft, the ring gear is non-rotatably connected to the third shaft and the planet carrier is non-rotatably connected to the fourth shaft. In this way, a suitable structure of the planetary gear set system can be realized, with two different transmission ratios between the input shaft and the output shaft being able to be represented for suitable integration of at least one electric machine by selective actuation of the two switching elements.

This results in a first transmission ratio between the input shaft and the output shaft by actuating the first switching element, while a second transmission ratio between the input shaft and the output shaft can be achieved by closing the second switching element.

The at least one “stepped planet” is to be understood as meaning a planet wheel which is rotatably mounted on the planet carrier and is equipped with two toothings lying axially next to one another. The respective stepped planet can be designed in one piece overall, but is preferably composed of two individual planet gears, each of which is provided with one of the gearings and are non-rotatably connected to one another and thereby form the respective stepped planet.

The subject matter of the invention is also a drive unit for an electric vehicle, this drive unit comprising at least one electric machine and an electric vehicle transmission according to one or more of the aforementioned variants. A rotor of the at least one electric machine is connected in a rotationally fixed manner to the drive shaft of the electric vehicle transmission. In this way, a compact drive unit for an electric vehicle can be implemented, in which case this drive unit can preferably be used as a central drive for driving drive wheels of a drive axle of the electric vehicle. For this purpose, the output shaft of the electric vehicle transmission according to the invention is then coupled to a downstream differential gear, which distributes drive power to the drive wheels of the drive axle as a transverse differential. Alternatively, the differential gear connected downstream can also be designed as a longitudinal differential, so that a drive power is distributed over a number of drive axles and accordingly the drive unit is also designed to drive a number of drive axles.

According to one embodiment of a drive unit, the at least one electric machine is arranged coaxially to the drive shaft of the electric vehicle transmission. As an alternative to this, an off-axis arrangement of the at least one electric machine relative to the drive shaft is also possible within the scope of the invention.

As an alternative or in addition to the aforementioned embodiment, the at least one electric machine and the electric vehicle transmission are accommodated in a common housing. As a result, the electric machine and the electric vehicle transmission can form a preassembled assembly. A control actuator is particularly preferred Actuation of the two switching elements of the electric vehicle transmission is arranged on the outside of this housing.

Furthermore, the invention relates to an electric vehicle in which at least one aforementioned drive unit is provided. This electric vehicle can particularly preferably be a commercial vehicle and in particular a truck or a bus.

The invention is not limited to the specified combination of features of the main claim or the claims dependent thereon. There are also possibilities of combining individual features with one another, even if they result from the claims, the following description of a preferred embodiment of the invention or directly from the drawings. Reference of the claims to the drawings by the use of reference signs is not intended to limit the scope of the claims.

• 1 eine schematische Ansicht eines Kraftfahrzeugantriebsstranges eines Elektrofahrzeugs;
• 2 eine schematische Darstellung einer Antriebseinheit des Kraftfahrzeugantriebsstranges aus 1, entsprechend einer bevorzugten Ausführungsform der Erfindung;
• 3 eine perspektivische Ansicht der Antriebseinheit aus 2;
• 4 eine Schnittansicht der Antriebseinheit aus 2;
• 5 und 6 je eine Detailansicht der Antriebseinheit aus 2, gezeigt in je einem Schaltzustand eines Elektrofahrzeuggetriebes der Antriebseinheit; und
• 7 ein beispielhaftes Schaltschema des Elektrofahrzeuggetriebes der Antriebseinheit aus den 2 bis 6.

An advantageous embodiment of the invention, which is explained below, is shown in the drawings. It shows:

• 1 a schematic view of a motor vehicle drive train of an electric vehicle;
• 2 a schematic representation of a drive unit of the motor vehicle drive train 1 , according to a preferred embodiment of the invention;
• 3 a perspective view of the drive unit 2 ;
• 4 a sectional view of the drive unit 2 ;
• 5 and 6 a detailed view of the drive unit 2 , shown in each switching state of an electric vehicle transmission of the drive unit; and
• 7 an exemplary circuit diagram of the electric vehicle transmission of the drive unit from the 2 until 6 .

1 shows a schematic view of a motor vehicle drive train 1 of an electric vehicle, which is preferably a truck or a bus. In this case, a drive unit 2 is provided in the motor vehicle drive train 1, which is downstream of a differential gear 3 on the output side. A drive power is distributed to drive wheels 4 and 5 of a drive axle of the electric vehicle via the differential gear 3 . As in 1 can be seen, the drive unit 2 and the differential gear 3 are aligned in the direction of travel of the electric vehicle. If necessary, the differential gear 3 can also be integrated into the drive unit 2 .

From the 2 until 4 show different views of the drive unit 2, which is designed according to a preferred embodiment of the invention. while showing 2 a schematic view, 3 a perspective view and 4 a sectional view. As in particular in the 2 and 4 As can be seen, the drive unit 2 is composed of an electric machine 6 and an electric vehicle transmission 7, which is implemented in accordance with a preferred embodiment of the invention.

The electric machine 6 comprises a stator 8 and a rotor 9, the stator 8 of which is permanently fixed to a housing 10 in which the electric machine 6 and the electric vehicle transmission 7 are housed together. The electric machine 6 can be operated on the one hand as a generator and on the other hand as an electric motor.

In addition to an input shaft 11 and an output shaft 12, the electric vehicle transmission 7 also has a planetary gear set system 13, to which four shafts 14, 15, 16 and 17 are assigned. The input shaft 11, the output shaft 12 and the shafts 14 to 17 are each coaxial with one another and are also placed coaxially with the rotor 9 and the stator 8 of the electric machine 6. As in 2 and also in 4 can be seen, the output shaft 12 and the shaft 17 are formed in one piece. In addition, the shaft 16 is permanently fixed to the housing 10, and this, as in particular in 4 can be seen, is realized via a driving teeth 18.

The electric vehicle transmission 7 is also equipped with two shifting elements A and B, which are each present as positive shifting elements in the form of unsynchronized dog shifting elements. In an actuated state, switching element A ensures a non-rotatable connection between drive shaft 11 and shaft 14 , while switching element B can be used to non-rotatably connect drive shaft 11 to shaft 15 when actuated.

The planetary gear set system 13 comprises a first sun gear 19, a second sun gear 20, a planet carrier 21 and a ring gear 22, with several stepped planets 23 being rotatably guided in the planet carrier 21, each of which is equipped with a first toothing 24 and a second toothing 25 are. The toothings 24 and 25 are formed axially next to one another on the individual step planet 23, where, as in the sectional view in 4 it can be seen that the first toothing 24 is formed on a planet wheel 26 , while the second toothing 25 is formed on a planet wheel 27 that is separate from the planet wheel 26 . The respective planetary gears 26 and 27 together form the individual stepped planet 23 in that the respective planetary gear 27 is designed to be axially extended and is connected to the respective planetary gear 26 of the individual stepped planetary gear 23 in a rotationally fixed manner at a driving toothing.

In the present case, the planetary gear set system 13 is provided axially between the electric machine 6 and a connection point 28 of the output shaft 12, with an output-side connection of the drive unit 2 to the motor vehicle drive train 1 in 1 subsequent differential gear 3 is produced. In a first gear plane 29 , the stepped planets 23 are each in meshing engagement with the first sun gear 19 at their respective first toothing 24 , with the first gear plane 29 being provided axially adjacent to the connection point 28 . Furthermore, the stepped planets 23 are in a second gear plane 30 at their second teeth 25 each with both the second sun gear 20 and the ring gear 22 in meshing engagement.

The first sun gear 19 is connected to the shaft 14 in a torque-proof manner, with the first sun gear 19 being - as in 4 can be seen - than configured on the shaft 14 toothing is present. In this respect, the sun gear 19 and the shaft 14 are formed in one piece. Likewise, the second sun wheel 20 is designed in one piece with the shaft 15 in that a toothing is configured on the shaft 15 in the corresponding area. Furthermore, the ring gear 22 is also designed in one piece with the shaft 16, for which purpose the shaft 16 is provided with a corresponding toothing on an inner circumference. Due to the permanent, non-rotatable connection of the shaft 16 to the housing 10, the ring gear 22 is also permanently fixed. The planet carrier 21, on the other hand, is permanently connected to the shaft 17 and thus also to the output shaft 12 in a rotationally fixed manner.

As a special feature, the switching elements A and B are placed axially at the height of the electric machine 6 and lying radially on the inside of the latter. For this purpose, the drive shaft 11 is designed as a hollow shaft 31 which is non-rotatably connected to the rotor 9 of the electric machine 6 on an outer circumference at a connection area 32 . Axially at the level of this connection area 32 and radially on the inside of this, the hollow shaft 31 can also be connected in a rotationally fixed manner on an inner circumference 33 via the shifting elements A and B located there either to the shaft 14 or to the shaft 15 .

The two switching elements A and B are part of a switching device 34 which has an actuating element in the form of a sliding sleeve 35 . This sliding sleeve 35 is guided in an axially displaceable manner in the hollow shaft 31, for which purpose the sliding sleeve 35 is provided on an outer circumference with a driving toothing 36 which meshes with a driving toothing 37 which is configured on the inner circumference 33 of the hollow shaft 31 in the corresponding area . In addition, the sliding sleeve 35 also has a further driving toothing 38 on an inner circumference and in the area of an axial end face, on which it can engage in a corresponding driving toothing 39 of the shaft 14 or in a corresponding driving toothing 40 of the shaft 15, depending on its axial position. In a first switching position and when engaged in the driving toothing 39, the sliding sleeve 35 subsequently produces a non-rotatable connection between the hollow shaft 31 and the shaft 14, whereas in a second switching position of the sliding sleeve 35 when the driving toothing 38 of the sliding sleeve 35 meshes with the driving toothing 40 the hollow shaft 31 and the shaft 15 are connected to one another in a rotationally fixed manner via the sliding sleeve 35 . The driving teeth 39 and 40 are each configured on the shaft ends of the shafts 14 and 15, with which the shafts 14 and 15 are inserted axially into the hollow shaft 31.

An axial displacement of the sliding sleeve 35 between its switching positions and a neutral position, in which neither a tooth engagement of the driving toothing 38 with the driving toothing 39 nor the driving toothing 40 is shown, is initiated via a positioning actuator 41, which is placed outside of the housing 10 in the present case. The positioning actuator 41 is provided axially at one end of the drive unit 2 which is opposite to the axial end at which the output shaft 12 with the connection point 28 is led out of the housing 10 . The setting actuator 41 is an electromechanical actuator which, when power is supplied, generates a setting movement in the form of a rotary movement on a setting shaft 42 .

As in 4 As can be seen, the actuating actuator 41 is coupled to the sliding sleeve 35 via a coupling rod 43 which is guided radially on the inside through the hollow shaft 31 and is axially connected at one axial end to the sliding sleeve 35 via an intermediate roller bearing 44 . The coupling rod 43 transmits an axial adjustment movement introduced into it to the sliding sleeve 35. Axially on the side of the adjustment actuator 41, the coupling rod 43 is designed as a rack 45, with a toothing of this rack 45 enclosing a spur gear 46, which is non-rotatably mounted on the adjustment shaft 42 of the actuating actuator 41 is placed. The rotational movement of the setting actuator 41 is correspondingly converted into an axial setting movement of the coupling rod 43 by the meshing of the spur gear 46 and the toothed rack 45 .

In the electric vehicle transmission 7, two different transmission ratios can be switched between the input shaft 11 and the output shaft 12, with a circuit of these transmission ratios being detailed in the 5 and 6 shown and also in 7 is tabulated.

A first transmission ratio G1 can thus be switched by actuating the switching element A of the switching device 34, for which purpose the sliding sleeve 35 is moved into the in 5 switching position shown is moved axially, in which the sliding sleeve 35 with the driving toothing 38 engages in the driving toothing 39 of the shaft 14 . As a result, the power flow is guided from the drive shaft 11 via the shaft 14 to the output shaft 12 , the power flow being guided via the meshing of the stepped planets 23 on their first toothings 24 with the first sun wheel 19 .

In addition, a second transmission ratio G2 can be switched by the switching element B being actuated. For this purpose, the sliding sleeve 35 is to be moved via the setting actuator 41 into the axial switching position, in which the sliding sleeve 35 engages with the driving toothing 38 in the driving toothing 40 of the shaft 15 . As a result, the power flow is guided from the drive shaft 11 via the shaft 15 to the output shaft 12 , the power flow being guided by meshing of the stepped planets 23 at their second toothing 25 with the second sun gear 20 .

Switching between the shifting elements A and B can take place through speed synchronization via the electric machine 6, in that the electric machine 6 is operated in a targeted manner in such a way that, with regard to the shifting element A or B that is to be engaged, synchronous speeds are generated between the sliding sleeve 35 and the respective shaft 14 or 15 set.

Because the shifting device 34 is placed radially on the inside within the hollow shaft 31 that forms the drive shaft 11, an overall axial length of the electric vehicle transmission 7 can be significantly reduced. Overall, a drive device 2 with a compact design can also be implemented as a result.

Reference List

1

automotive powertrain

2

drive unit

3

differential gear

4

drive wheel

5

drive wheel

6

electric machine

7

electric vehicle transmission

8th

stator

9

rotor

10

Housing

11

drive shaft

12

output shaft

13

planetary gear system

14

Wave

15

Wave

16

Wave

17

Wave

18

driving teeth

19

first sun gear

20

second sun wheel

21

planetary web

22

ring gear

23

stepped planets

24

first gearing

25

second toothing

26

planet wheel

27

planet wheel

28

junction

29

wheel plane

30

wheel plane

31

hollow shaft

32

connection area

33

inner circumference

34

switching device

35

sliding sleeve

36

driving teeth

37

driving teeth

38

driving teeth

39

driving teeth

40

driving teeth

41

positioning actuator

42

control shaft

43

connecting rod

44

roller bearing

45

rack

46

spur gear

A

switching element

B

switching element

G1

gear ratio

G2

gear ratio

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018129175 A1 [0003]

Claims (14)

Electric vehicle transmission (7), comprising an input shaft (11) which is provided for connection to at least one electric machine (6), an output shaft (12) and a planetary gear set system (13), the planetary gear set system having a first shaft (14), a second Shaft (15), a third shaft (16) and a fourth shaft (17) are assigned, of which the third shaft (16) is fixed and the fourth shaft (17) is non-rotatably connected to the output shaft (12), with a first Switching element (A) and a second switching element (B) are provided, of which the first switching element (A) in an actuated state connects the drive shaft (11) and the first shaft (14) in a rotationally fixed manner, whereas the second switching element (B) in an actuated state brings about a non-rotatable connection between the drive shaft (11) and the second shaft (15), characterized in that the drive shaft (11) is formed at least in sections by a hollow shaft (31), and there ss the first shifting element (A) and the second shifting element (B) are placed axially at least overlapping and radially on the inside of a connection area (32) of this hollow shaft (31), which radially on the outside is used to establish the connection of the drive shaft (11) to the at least an electric machine (6) is used. Electric vehicle transmission (7) after claim 1 , characterized in that the first shifting element (A) and the second shifting element (B) are designed as positive shifting elements, preferably as unsynchronized claw shifting elements. Electric vehicle transmission (7) after claim 2 , characterized in that the first switching element (A) and the second switching element (B) are part of a switching device (34) which has an axially displaceable actuating element, the actuating element depending on its axial position on the one hand the actuated state of the first switching element ( A) and on the other hand brings about the actuated state of the second switching element (B). Electric vehicle transmission (7) after claim 3 , characterized in that the actuating element is designed as a sliding sleeve (35), the sliding sleeve (35) being equipped on an outer circumference with a first driving toothing (36) via which the sliding sleeve (35) can be displaced axially on a driving toothing (37) of the hollow shaft (31), and wherein the inner circumference of the sliding sleeve (35) is also provided with a second carrier toothing (38) on which the sliding sleeve (35) meshes with a carrier toothing (39) when it is axially displaced into a first switching position. of the first shaft (14) and, in a second switching position, meshes with a driving toothing (40) of the second shaft (15). Electric vehicle transmission (7) after claim 4 , characterized in that the first shaft (14) and the second shaft (15) are each guided axially into the hollow shaft (31) with shaft ends, with the respective driving teeth (39, 40) for the toothed engagement with the sliding sleeve being on the shaft ends (35) is formed. Electric vehicle transmission (7) according to one of claims 3 until 5 , characterized in that the actuating element is coupled to a positioning actuator (41) via which an axial displacement of the actuating element can be initiated. Electric vehicle transmission (7) after claim 6 , characterized in that the setting actuator (41) is placed axially on a side of the drive shaft (11) facing away from the first (14) and the second shaft (15), the coupling of the setting actuator (41) to the actuating element being via a coupling rod (43) is completed. Electric vehicle transmission (7) after claim 7 , characterized in that the coupling rod (43) is designed as a toothed rack (45) at least at one end facing the setting actuator (41), with a toothing of the toothed rack (45) being in toothed engagement with a spur gear (46) which rotates fixedly on an actuating shaft (42) of the actuating actuator (41) lying transversely to the coupling rod (43). Electric vehicle transmission (7) according to one of the preceding claims, characterized in that the planetary gear set system (7) has a first sun gear (19), a second sun gear (20), a ring gear (22) and a planet carrier (21) which has at least one stepped planet (23) rotatably mounted, the at least one stepped planet (23) on a first toothing (24) with the first sun gear (19) and on a second toothing (25) with the second sun gear (20) and the ring gear (22) in each case meshing, and wherein the first sun wheel (19) is non-rotatably connected to the first shaft (14), the second sun wheel (20) is non-rotatably connected to the second shaft (15), the ring gear (22) is non-rotatably connected to the third shaft (16) and the planet carrier (21) is non-rotatably connected to the fourth shaft (17). Electric vehicle transmission (7) after claim 9 , characterized in that a first transmission ratio (G1) between the input shaft (11) and the output shaft (12) by actuating the first switching element (A) and a two tes transmission ratio (G2) between the input shaft (11) and the output shaft (12) by closing the second switching element (B). Drive unit (2) for an electric vehicle, comprising at least one electric machine (6) and an electric vehicle transmission (7) according to one or more of Claims 1 until 10 wherein a rotor (9) of the at least one electric machine (6) is non-rotatably connected to the drive shaft (11) of the electric vehicle transmission (7). Drive unit (2) after claim 11 , characterized in that the at least one electric machine (6) is arranged coaxially to the drive shaft (11) of the electric vehicle transmission (7). Drive unit (2) after claim 11 or 12 , characterized in that the at least one electric machine (6) and the electric vehicle transmission (7) are accommodated in a common housing (10). Electric vehicle, comprising at least one drive unit (2) according to one or more of Claims 11 until 13 .

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