DE102022213696A1 - Electric axle drive - Google Patents

Abstract

An electric axle drive with at least one electric machine (EM) and with a switchable transmission as well as with a first planetary gear set (PG 1) and a second planetary gear set (PG 2) coupled to the first planetary gear set (PG 1) as a transfer case for driving a first wheel output shaft (2A) and a second wheel output shaft (2b) is proposed, wherein a rotor shaft (1) of the electric machine (EM) is arranged axially parallel to the first wheel output shaft (2a) and the second wheel output shaft (2b), wherein the transmission comprises at least a first spur gear stage (RE 1) and a second spur gear stage (RE 2) with an associated first shifting element (SE 1) and a third planetary gear set (PG3) with an associated second shifting element (SE 2) for realizing several gears (gear 1, gear 2, gear 3, gear 4), wherein the spur gear stages (RE 1, RE 2) are assigned to an intermediate shaft (3), wherein a The transmission output shaft (5) of the transmission is connected to the first planetary gear set (PG 1), the first planetary gear set (PG 1) being connected to the first wheel output shaft (2a) and the second planetary gear set (PG 2) being connected to the second wheel output shaft (2b), and the first planetary gear set (PG 1) and the second planetary gear set (PG 2) being arranged axially next to one another. A vehicle (16) with the electric axle drive is also proposed.

Description

The present invention relates to an electric axle drive with at least one electric machine with a switchable transmission and with a first planetary gear set and a second planetary gear set coupled to the first planetary gear set as a transfer case for driving a first wheel output shaft and a second wheel output shaft. The invention further relates to a vehicle with the electric axle drive.

For example, from the publication EN 10 2019 205 747 A1 A drive train with an electric machine and a transmission is known, which divides the drive torque of the electric machine between two output shafts. The transmission comprises an input shaft that is connected to a first planetary gear set, which is coupled to a second planetary gear set. Both the electric machine and the two planetary gear sets are arranged coaxially to the output shafts.

The present invention is based on the object of proposing an electric axle drive and a vehicle with the axle drive, which realize a construction that is as compact as possible with the smallest possible axial installation space requirement.

This object is achieved according to the invention by the features of patent claim 1 or 12, wherein advantageous and claimed further developments result from the subclaims and the description as well as the drawings.

Thus, an electric axle drive with at least one electric machine and with a switchable transmission as well as with a first planetary gear set and a second planetary gear set coupled to the first planetary gear set as a transfer case for driving a first wheel output shaft and a second wheel output shaft is proposed, wherein a rotor shaft of the electric machine is arranged axially parallel to the first wheel output shaft and the second wheel output shaft, wherein the transmission comprises at least a first spur gear stage and a second spur gear stage with an associated first shifting element and a third planetary gear set with an associated second shifting element for implementing several gears, wherein the spur gear stages are assigned to an intermediate shaft, wherein a transmission output shaft of the transmission is connected to the first planetary gear set, wherein the first planetary gear set is connected to the first wheel output shaft and the second planetary gear set is connected to the second wheel output shaft, and wherein the first planetary gear set and the second planetary gear set are arranged axially next to one another.

In this way, an electric axle drive for switching several gears with an integrated differential gear is implemented by two planetary gear sets arranged axially next to each other and coupled to each other, whereby the electric machine arranged axially parallel to the wheel output shafts and the planetary gear sets is coupled to them via an intermediate shaft, so that on the one hand a sufficient transmission ratio is provided with the smallest possible axial offset between the electric machine and the wheel output shafts and on the other hand axial installation space is saved. This ensures optimal integration of the electric machine in the proposed axle drive.

An arrangement that is particularly space-saving, particularly in the axial direction, is realized in the proposed electric axle drive in that the rotor shaft is connected to a first spur gear, which is in engagement with a second spur gear connected to the intermediate shaft, the intermediate shaft being connected to a fourth spur gear, the second spur gear being in engagement with a third spur gear and forming the first spur gear stage, the fourth spur gear being in engagement with a fifth spur gear and forming the second spur gear stage, and the third spur gear and the fifth spur gear are each assigned as idler gears to a transmission connecting shaft for coupling to the third planetary gear set. The transmission thus comprises two spur gear stages arranged axially next to one another as gear planes, with the axial installation space requirement being kept as low as possible since the rotor shaft is only equipped with one spur gear. The intermediate shaft provided for bridging the axle distance enables spur gears to be as small as possible, and the additional third planetary gear set enables further gear ratios to be realized in the proposed axle drive.

In order to realize, for example, two switchable gears in the proposed electric axle drive, it is provided that the first switching element is assigned to the third spur gear and the fifth spur gear, wherein in a first switching position of the first switching element the third spur gear is connected to the transmission connecting shaft and wherein in a second switching position of the first switching element the fifth spur gear is connected to the transmission connecting shaft.

For a further two switchable gears in the proposed electric axle drive, it is provided that the second switching element is assigned to two elements of the third planetary gear set in such a way that in a third switching position of the second switching element, two elements of the third planet gear set are connected to one another and that in a fourth switching position of the second switching element one of the elements of the third planetary gear set is connected to a housing. By fixing an element of the third planetary gear set on the housing side or by connecting two elements or by blocking the third planetary gear set, further transmission ratios can be transmitted to the wheel output shafts.

It is particularly advantageous in the proposed axle drive if the main gear, which is used for a large proportion of the time during operation, is implemented via the spur gears of the first spur gear stage, as this reduces the forces on the intermediate shaft and has advantages in terms of the design and efficiency of the proposed axle drive.

In order to block the third planetary gear set to implement, for example, the first and second gears, three blocking options are fundamentally possible, in each of which two of the three elements of the third planetary gear set are connected to one another. Preferably, in the proposed axle drive, the second switching element can be assigned to a ring gear of the third planetary gear set and a sun gear of the third planetary gear set, wherein in the third switching position the ring gear of the third planetary gear set is connected to the sun gear of the third planetary gear set. Within the scope of a further blocking variant of the invention, it can be provided that the second switching element is assigned to the ring gear of the third planetary gear set and a planet gear carrier of the third planetary gear set, wherein in the third switching position of the second switching element the ring gear of the third planetary gear set is connected to the planet gear carrier of the third planetary gear set.

The two planetary gear sets arranged axially next to one another form an integrated differential gear, which enables a particularly compact design in the proposed axle drive. For structurally simple and space-saving coupling with the third planetary gear set, it is preferably provided that the transmission output shaft connected to the planetary gear carrier of the third planetary gear set is connected to a sun gear of the first planetary gear set, wherein a planetary gear carrier of the first planetary gear set is connected to the first wheel output shaft, wherein a ring gear of the first planetary gear set is connected to a sun gear of the second planetary gear set, wherein a ring gear of the second planetary gear set is connected to the second wheel output shaft, and wherein a planetary gear carrier of the second planetary gear set is connected to a housing.

A particularly compact design is realized in the proposed electric axle drive in that the transmission connecting shaft and the transmission output shaft as well as the first planetary gear set and the second planetary gear set as well as the third planetary gear set are arranged coaxially to one another.

In the proposed electric axle drive, switching between the gears of the transmission is carried out by a traction-interrupted switching, which is why the first switching element and the second switching element can be designed in a cost-effective manner, for example as a positive switching element, preferably as a claw clutch or the like. Synchronization is advantageously carried out simply via the electric machine.

The object underlying the invention is also achieved by a vehicle with at least one electric axle drive as described above. This results in the advantages already described and further advantages.

The present invention is further explained below with reference to the drawings.

• 1 eine schematische Ansicht einer ersten Ausführungsvariante eines erfindungsgemäßen elektrischen Achsantriebes eines Fahrzeuges;
• 2 eine schematische Ansicht einer zweiten Ausführungsvariante des elektrischen Achsantriebes; und
• 3 ein Schaltschema für die beiden Ausführungsvarianten des elektrischen Achsantriebes.

Show it:

• 1 a schematic view of a first embodiment of an electric axle drive of a vehicle according to the invention;
• 2 a schematic view of a second embodiment of the electric axle drive; and
• 3 a circuit diagram for the two versions of the electric axle drive.

In the 1 and 2 are exemplary schematic views of the embodiment variants of an electric axle drive of a vehicle 16 according to the invention, wherein 3 shows a gear shift diagram for the switchable gears, for example gear 1, gear 2, gear 3, gear 4, for the proposed electric axle drive.

Regardless of the design variants, the electric axle drive comprises at least one electric machine EM and a switchable transmission as well as a first planetary gear set PG 1 and a second planetary gear set PG 2 coupled to the first planetary gear set PG 1 as a transfer case for driving a first wheel output shaft 2A and a second wheel output shaft 2b. A rotor shaft 1 of the electric machine EM is arranged axially parallel to the first wheel output shaft 2a and the second wheel output shaft 2b.

The transmission comprises at least a first spur gear stage RE 1 and a second spur gear stage RE 2 with an associated first shifting element SE 1 and a third planetary gear set PG3 with an associated second shifting element SE 2 for realizing at least four gears gear 1, gear 2, gear 3, gear 4. The two spur gear stages RE 1, RE 2 are assigned to an intermediate shaft 3, wherein a transmission output shaft 5 of the transmission is connected to the first planetary gear set PG 1, wherein the first planetary gear set PG 1 is connected to the first wheel output shaft 2a and the second planetary gear set PG 2 is connected to the second wheel output shaft 2b, and wherein the first planetary gear set PG 1 and the second planetary gear set PG 2 are arranged axially next to one another in an integrated transfer case or differential gear.

In detail, the rotor shaft 1 is connected to a first spur gear 1, which meshes with a second spur gear 2 connected to the intermediate shaft 3. The intermediate shaft 3 is connected to a fourth spur gear 4. The second spur gear 2 meshes with a third spur gear 3 and forms the first spur gear stage RE1. The fourth spur gear 4 meshes with a fifth spur gear 5 and forms the second spur gear stage RE 2. The third spur gear 3 and the fifth spur gear 5 are each assigned as loose gears to a transmission connecting shaft 4 for coupling to the third planetary gear set PG 3.

To realize the four gears gear 1, gear 2, gear 3, gear 4, the first switching element SE 1 is assigned to the two spur gear stages RE1 and RE2 and the second switching element SE 2 is assigned to the third planetary gear set PG 3.

The first switching element SE 1 is assigned to the third spur gear 3 and the fifth spur gear 5, wherein in a first switching position a of the first switching element SE 1 the third spur gear 3 is connected to the transmission connecting shaft 4 and wherein in a second switching position b of the first switching element SE 1 the fifth spur gear 5 is connected to the transmission connecting shaft 4.

The second switching element SE 2 is assigned to two elements of the third planetary gear set PG 3 such that in a third switching position c of the second switching element SE 2 two elements of the third planetary gear set PG 3 are connected to one another and that in a fourth switching position d of the second switching element SE 2 one of the elements of the third planetary gear set PG 3 is connected to a housing 15.

In 1 a first embodiment of the electric axle drive with a first blocking variant of the third planetary gear set PG 3 is shown, in which the second switching element SE 2 is assigned to a ring gear 6 of the third planetary gear set PG 3 and a sun gear 7 of the third planetary gear set PG 3 connected to the transmission connecting shaft 4.

In 2 a second embodiment of the electric axle drive with a second blocking variant of the third planetary gear set PG 3 is shown, in which the second switching element SE 2 is assigned to the ring gear 6 of the third planetary gear set PG 3 and a planetary gear carrier 8 of the third planetary gear set PG 3.

The third planetary gear set PG 3, which is designed as part of the switchable transmission, is connected to a sun gear 9 of the first planetary gear set PG 1 via the planet gear carrier 8 connected to the transmission output shaft 5, with a planet gear carrier 10 of the first planetary gear set PG1 being connected to the first wheel output shaft 2a. A ring gear 11 of the first planetary gear set PG 1 is connected to a sun gear 12 of the second planetary gear set PG 2, with a ring gear 13 of the second planetary gear set PG 2 being connected to the second wheel output shaft 2b, and with a planet gear carrier 14 of the second planetary gear set PG 2 being connected to a housing 15.

In the electric drive axle, the first planetary gear set PG 1 and the second planetary gear set PG 2 as well as the third planetary gear set PG 3 are arranged axially next to one another. Furthermore, the transmission connecting shaft 4 and the transmission output shaft 5 as well as the first planetary gear set PG 1 and the second planetary gear set PG 2 as well as the third planetary gear set PG 3 are arranged coaxially to one another.

Regardless of the respective design variants, a double switching element with an actuator is provided as the switching element. However, it is also entirely conceivable that the function is carried out by two separate switching elements.

In 3 a circuit diagram of the electric axle drive according to the invention is shown, which applies to both design variants. In the circuit diagram, the gears to be shifted, gear 1, gear 2, gear 3, gear 4, and the switching positions a, b, c, d of the two switching elements SE 1 and SE 2 to be engaged are marked by a corresponding X in the circuit diagram.

From the switching diagram it can be seen that to switch a first gear, gear 1, the second switching position b on the first switching element SE 1 and the third switching position c are engaged in the second switching element SE 2, that for shifting a second gear gear 2 the first switching position a are engaged in the first switching element SE 1 and the third switching position c are engaged in the second switching element SE 2, that for shifting a third gear gear 3 the second switching position b are engaged in the first switching element SE 1 and the fourth switching position d are engaged in the second switching element SE 2, and/or that for shifting a fourth gear gear 4 the first switching position a are engaged in the first switching element SE 1 and the fourth switching position d are engaged in the second switching element SE 2.

Reference symbols

1

Rotor shaft

2a

first wheel output shaft

2 B

second wheel output shaft

3

Intermediate shaft

4

Gearbox connecting shaft

5

Gearbox output shaft

6

Ring gear of the third planetary gear set

7

Sun gear of the third planetary gear set

8th

Planetary gear carrier of the third planetary gear set

9

Sun gear of the first planetary gear set

10

Planetary gear carrier of the first planetary gear set

11

Ring gear of the first planetary gear set

12

Sun gear of the second planetary gear set

13

Ring gear of the second planetary gear set

14

Planetary gear carrier of the second planetary gear set

15

Housing

16

vehicle

PG1

first planetary gear set

PG2

second planetary gear set

PG3

third planetary gear set

RE1

first spur gear stage

RE2

second spur gear stage

EM

electric machine

SE1

first switching element

SE2

second switching element

Wheel 1

first spur gear

Wheel 2

second spur gear

Wheel 3

third spur gear

Wheel 4

fourth spur gear

Wheel 5

fifth spur gear

a

first switching position of the first switching element

b

second switching position of the first switching element

c

third switching position of the second switching element

d

fourth switching position of the second switching element

i

translation

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• DE 102019205747 A1 [0002]

Claims (12)

Electric axle drive with at least one electric machine (EM) and with a switchable transmission and with a first planetary gear set (PG 1) and a second planetary gear set (PG 2) coupled to the first planetary gear set (PG 1) as a transfer case for driving a first wheel output shaft (2A) and a second wheel output shaft (2b), wherein a rotor shaft (1) of the electric machine (EM) is arranged axially parallel to the first wheel output shaft (2a) and the second wheel output shaft (2b), wherein the transmission comprises at least a first spur gear stage (RE 1) and a second spur gear stage (RE 2) with an associated first shifting element (SE 1) and a third planetary gear set (PG3) with an associated second shifting element (SE 2) for realizing several gears (gear 1, gear 2, gear 3, gear 4), wherein the spur gear stages (RE 1, RE 2) are assigned to an intermediate shaft (3), wherein a transmission output shaft (5) of the transmission is connected to the first planetary gear set (PG 1), wherein the first planetary gear set (PG 1) is connected to the first wheel output shaft (2a) and the second planetary gear set (PG 2) is connected to the second wheel output shaft (2b), and wherein the first planetary gear set (PG 1) and the second planetary gear set (PG 2) are arranged axially next to one another. Electric axle drive according to Claim 1 , characterized in that the rotor shaft (1) is connected to a first spur gear (gear 1) which is in engagement with a second spur gear (gear 2) connected to the intermediate shaft (3), that the intermediate shaft (3) is connected to a fourth spur gear (gear 4), that the second spur gear (gear 2) is in engagement with a third spur gear (gear 3) and forms the first spur gear stage (RE1), that the fourth spur gear (gear 4) is in engagement with a fifth spur gear (gear 5) and forms the second spur gear stage (RE 2), and that the third spur gear (gear 3) and the fifth spur gear (gear 5) are each assigned as loose gears to a transmission connecting shaft (4) for coupling to the third planetary gear set (PG 3). Electric axle drive according to Claim 2 , characterized in that the first switching element (SE 1) is assigned to the third spur gear (gear 3) and the fifth spur gear (gear 5), wherein in a first switching position (a) of the first switching element (SE 1) the third spur gear (gear 3) is connected to the transmission connecting shaft (4) and wherein in a second switching position (b) of the first switching element (SE 1) the fifth spur gear (gear 5) is connected to the transmission connecting shaft (4). Electric axle drive according to one of the preceding claims, characterized in that the second switching element (SE 2) is assigned to two elements of the third planetary gear set (PG 3) such that in a third switching position (c) of the second switching element (SE 2) two elements of the third planetary gear set (PG 3) are connected to one another and that in a fourth switching position (d) of the second switching element (SE 2) one of the elements of the third planetary gear set (PG 3) is connected to a housing (15). Electric axle drive according to Claim 3 and 4 , characterized in that for shifting a first gear (gear 1) the second shift position (b) is engaged in the first shift element (SE 1) and the third shift position (c) in the second shift element (SE 2), that for shifting a second gear (gear 2) the first shift position (a) is engaged in the first shift element (SE 1) and the third shift position (c) in the second shift element (SE 2), that for shifting a third gear (gear 3) the second shift position (b) is engaged in the first shift element (SE 1) and the fourth shift position (d) in the second shift element (SE 2), and/or that for shifting a fourth gear (gear 4) the first shift position (a) is engaged in the first shift element (SE 1) and the fourth shift position (d) in the second shift element (SE 2). Electric axle drive according to one of the preceding claims, characterized in that the second switching element (SE 2) is assigned to a ring gear (6) of the third planetary gear set (PG 3) and to a sun gear (7) of the third planetary gear set (PG 3) connected to the transmission connecting shaft (4). Electric axle drive according to one of the Claims 1 until 5 , characterized in that the second switching element (SE 2) is assigned to a ring gear (6) of the third planetary gear set (PG 3) and to a planetary gear carrier (8) of the third planetary gear set (PG 3). Electric axle drive according to one of the preceding claims, characterized in that the transmission output shaft (5) connected to a planetary gear carrier (8) of the third planetary gear set (PG 3) is connected to a sun gear (9) of the first planetary gear set (PG 1), that a planetary gear carrier (10) of the first planetary gear set (PG1) is connected to the first wheel output shaft (2a), that a ring gear (11) of the first planetary gear set (PG 1) is connected to a sun gear (12) of the second planetary gear set (PG 2), that a ring gear (13) of the second planetary gear set (PG 2) is connected to the second wheel output shaft (2b), and that a planetary gear carrier (14) of the second planetary gear set (PG 2) is connected to a housing (15). Electric axle drive according to one of the preceding claims, characterized in that the transmission connecting shaft (4) and the transmission output shaft (4) as well as the first planetary gear set (PG 1) and the second planetary gear set (PG 2) as well as the third planetary gear set (PG 3) are arranged coaxially to one another. Electric axle drive according to one of the preceding claims, characterized in that the first planetary gear set (PG 1) and the second planetary gear set (PG 2) as well as the third planetary gear set (PG 3) are arranged axially next to one another. Electric axle drive according to one of the preceding claims, characterized in that the first switching element (SE 1) and the second switching element (SE 2) are each designed as a positive-locking claw clutch. Vehicle (16) with at least one electric axle drive according to one of the preceding claims.

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