DE102021204472A1 - Electric drive for a vehicle - Google Patents

Abstract

An electric drive for a vehicle has an electric machine (1) with a rotor shaft (2) which is coupled via a transmission gear to a transfer case (3) for driving output shafts (4, 5), the output shafts (4th , 5) and the rotor shaft (2) are arranged axially parallel to one another, with at least one first spur gear stage (6) for realizing a first translation stage and at least one second spur gear stage (7) for realizing a second translation stage being provided as the transmission gear and with first spur gears ( 8, 9) of the spur gear stages (6, 7) of a common transmission input shaft (10) and second spur gears (11, 12) of the spur gear stages (6,7) are assigned to the transfer case (3). Furthermore, a vehicle with the electric drive is proposed.

Description

The present invention relates to an electric drive for a vehicle according to the type defined in more detail in the preamble of patent claim 1. The invention also relates to a vehicle with the electric drive.

For example from the publication DE 10 2012 110 269 A1 a drive train of a purely electrically driven vehicle with a transmission is known. The transmission has a standardized housing for accommodating two electrical machines and for accommodating two transmission output shafts, which are assigned to a vehicle axle. To drive the two transmission output shafts, either one electric machine or two electric machines are each connected to the transfer case or summing gear with their drive pinion. As a result, the translation is significantly limited in the known drive train.

The present invention is based on the object of proposing an electric drive and a vehicle with the electric drive, which implement multiple transmission stages as tree-neutrally and efficiently as possible, as well as cost-effectively.

This object is achieved according to the invention by the features of claim 1 or 11, advantageous and claimed developments resulting from the claims and the description and the drawings.

Thus, an electric drive for a vehicle with an electric machine of a rotor shaft is proposed, which is coupled via a transmission gear to a transfer case for driving output shafts, the output shafts and the rotor shaft being arranged axially parallel to one another. In order to implement a plurality of gear ratios as efficiently and inexpensively as possible in terms of installation space, it is provided that at least a first spur gear stage for realizing a first gear ratio stage and at least a second spur gear stage for realizing a second gear ratio are provided as the transmission gear, and that first spur gears of the spur gear stages of a common transmission input shaft and second spur gears are provided in each case Spur gears of the spur gear stages are assigned to the transfer case.

In this way, an electric drive with a plurality of gear ratios is created in a particularly space-saving and efficient manner, without an intermediate shaft and corresponding bearings for the intermediate shaft being required. Due to the fact that the spur gear stages are assigned to a common transmission input shaft, the transmission stages are realized in parallel next to one another with a particularly simple structural design.

In the case of the proposed electric drive, a particularly structurally simple and cost-effective embodiment provides that the rotor shaft of the electric machine forms the common transmission input shaft. As a result, no further shafts are required since the first spur gears of the spur gear stages are assigned to the rotor shaft.

It is also possible within the scope of the present invention for the common transmission input shaft to be arranged coaxially with the rotor shaft and to be connected to it in a torque-proof manner. With such a split shaft design, there are also assembly advantages.

Irrespective of the above statements, the electric drive provides that the first spur gears of the two spur gear stages assigned to the transmission input shaft are designed as switchable idler wheels, which can be connected to the transmission input shaft in a rotationally fixed manner via at least one switching element or the like in the switched state.

An alternative design provides that the shiftability is not realized on the transmission input shaft, but via the second spur gears of the spur gear stages in the area of the transfer case. For this purpose, it is provided in the electric drive that the second spur gears of the two spur gear stages assigned to the transfer case are designed as switchable idler gears that can be connected to the transfer case in a rotationally fixed manner via at least one switching element or the like in the switched state.

Irrespective of the two aforementioned statements with regard to shiftability, the arrangement of the shiftable idler gears on an associated shaft is particularly advantageous, since in this way a so-called disconnect function can be implemented in the proposed electric drive without additional components. With the disconnect function, the drive is decoupled from the output if necessary to increase efficiency.

For example, single switching elements can be used as the switching element, so that each loose wheel is assigned a switching element for switching or actuating. It is also conceivable that a double switching element is used, with which both loose wheels can be switched.

In order to increase efficiency and reduce costs, preferably form-fitting Switching elements, such as switching claws or the like are used as switching elements. It is also possible for frictional synchronizations to be used as shifting elements in order to ensure complete power shifting capability in the transmission. It is also conceivable that both positive-locking shifting elements and friction-locking synchronizations are used in order to realize at least partial power shifting capability in the transmission.

In the proposed electric drive, a spur gear differential gear, a bevel gear differential gear or the like can be used as the transfer case.

A further aspect of the present invention claims a vehicle with the electric drive described above. It is possible here for the electric drive to form an electric drive axle. It is also possible that several electric drives are assigned to the vehicle.

The present invention is explained in more detail below with reference to the drawings.

• 1 eine schematische Ansicht einer ersten Ausführungsvariante eines erfindungsgemäßen elektrischen Antriebes;
• 2 eine schematische Ansicht einer zweiten Ausführungsvariante des elektrischen Antriebes mit axial vertauschter Anordnung der Stirnradstufen;
• 3 eine schematische Ansicht einer dritten Ausführungsvariante des elektrischen Antriebes mit einem schaltbaren Verteilergetriebe;
• 4 eine vierte Ausführungsvariante als geschnittene Detailansicht des elektrischen Antriebes mit einer Rotorwelle als Getriebeeingangswelle;
• 5 eine fünfte Ausführungsvariante als geschnittene Detailansicht des elektrischen Antriebes mit einer geteilten Wellenanordnung von Rotorwelle und Getriebeeingangswelle; und
• 6 eine sechste Ausführungsvariante als geschnittene Detailansicht des elektrischen Antriebes mit Druckkämmen zur axialen Lagerung der Stirnräder.

Show it:

• 1 a schematic view of a first embodiment of an electric drive according to the invention;
• 2 a schematic view of a second embodiment variant of the electric drive with an axially reversed arrangement of the spur gear stages;
• 3 a schematic view of a third embodiment of the electric drive with a switchable transfer case;
• 4 a fourth variant as a sectional detailed view of the electric drive with a rotor shaft as the transmission input shaft;
• 5 a fifth embodiment as a detailed sectional view of the electric drive with a split shaft arrangement of rotor shaft and transmission input shaft; and
• 6 a sixth variant as a sectional detailed view of the electric drive with pressure combs for the axial bearing of the spur gears.

In the 1 until 6 various possible embodiments of an electric drive according to the invention for a vehicle are shown as examples.

Irrespective of the respective embodiment variants, the electric drive has an electric machine 1 with a rotor shaft 2, the details of the electric machine 1, such as the rotor arrangement and stator arrangement, not being shown in any more detail.

The rotor shaft 2 is coupled via a transmission gear to a transfer case 3 for driving output shafts 4.5, the output shafts 4.5 driving the wheels of the vehicle, not shown. The output shafts 4.5 and the rotor shaft 2 are arranged axially parallel to one another.

In order to realize a particularly efficient electric drive that is economical in terms of installation space and production, it is provided that at least a first spur gear stage 6 for realizing a first translation stage or a first gear and at least a second spur gear stage 7 for realizing a second spur gear stage or a second gear are provided as the transmission gear are provided. The first spur gears 8 , 9 of the spur gear stages 6 , 7 of a common transmission input shaft 10 and the second spur gears 11 , 12 of the spur gear stages 6 , 7 are assigned to the transfer case 3 with particular advantage.

Regardless of the respective embodiment variants, the two transmission stages are realized by the first spur gear stage 6 and the second spur gear stage 7, in that in the first spur gear stage 6 the first spur gear 8 of the first spur gear stage 6 meshes with the second spur gear 11 of the first spur gear stage 6 and in the second Spur gear stage 7, the first spur gear 9 of the second spur gear stage 7 meshes with the second spur gear 12 of the second spur gear stage 7, with the first spur gears 8, 9 of the spur gear stages 6, 7 or the second spur gears 11, 12 of the spur gear stages 6, 7 being designed as idler gears, which a switching element 13 is assigned to realize the respective gear ratio.

In 1 a first embodiment of the electric drive is shown, in which the first spur gears 8, 9 of the spur gear stages 6, 7 are assigned to the transmission input shaft 10 as switchable idler wheels, which can be connected to the transmission input shaft 10 in a rotationally fixed manner via the switching element 13 in the switched state.

In 2 a second embodiment of the electric drive is shown, in which the axial arrangement of the spur gears 6, 7 are reversed compared to the first embodiment.

3 shows a third embodiment of the electric drive in which the switchability of the spur gear stages 6, 7 is assigned to the transfer case 3, so that the second spur gears 11, 12 of the spur gear stages 6, 7 assigned to the transfer case 3 are designed as shiftable idler gears, which can be connected to the transfer case 3 in a torque-proof manner via the shifting element 13 in the shifted state.

In 4 a sectional detailed view of the electric drive is shown as a fourth embodiment variant, in which the rotor shaft 2 of the electric machine 1 forms the transmission input shaft 10 . Furthermore, a loose bearing 14 and a fixed bearing 15 on the rotor shaft 2 and on the transmission input shaft 10 are shown in this embodiment. In addition, corresponding axial bearings 16, 17 are shown for the first spur gears 8, 9 of the spur gear stages 6, 7, which are designed as idler gears.

5 shows a fifth embodiment variant as a detailed sectional view of the electric drive, in which a split shaft design is provided. In the case of the split shaft design, the common transmission input shaft 10 is arranged coaxially to the rotor shaft 2 of the electric machine and is connected to it in a torque-proof manner.

Finally shows 6 a sixth embodiment variant as a sectional detail view of the electric drive, in which pressure combs 18, 19 are provided for the axial bearing of the first spur gears 8, 9 of the spur gear stages 6, 7, which are designed as idler gears.

Reference List

1

electrical machine

2

rotor shaft

3

transfer case

4

output shaft

5

drive shaft

6

first spur gear stage

7

second spur gear stage

8th

first spur gear of the first spur gear stage

9

first spur gear of the second spur gear stage

10

transmission input shaft

11

second spur gear of the first spur gear stage

12

second spur gear of the second spur gear stage

13

switching element

14

floating bearing

15

fixed bearing

16

thrust bearing

17

thrust bearing

18

pressure comb

19

pressure comb

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 102012110269 A1 [0002]

Claims (11)

Electric drive for a vehicle with an electric machine (1) with a rotor shaft (2) which is coupled via a transmission gear to a transfer case (3) for driving output shafts (4.5), the output shafts (4.5) and the rotor shaft (2) are arranged axially parallel to one another, characterized in that at least a first spur gear stage (6) for realizing a first gear stage and at least a second spur gear stage (7) for realizing a second gear stage are provided as the transmission gear and that first spur gears (8th , 9) of the spur gear stages (6, 7) of a common transmission input shaft (10) and second spur gears (11, 12) of the spur gear stages (6,7) are assigned to the transfer case (3). Electric drive after claim 1 , characterized in that the rotor shaft (2) of the electrical machine (1) forms the common transmission input shaft (10). Electric drive after claim 1 , characterized in that the common transmission input shaft (10) is arranged coaxially to the rotor shaft (2) and is non-rotatably connected to it. Electric drive according to one of the preceding claims, characterized in that the first spur gears (8, 9) of the two spur gear stages (6, 7) assigned to the transmission input shaft (10) are designed as shiftable idler gears which can be shifted via at least one shifting element (13) in the shifted State non-rotatably connected to the transmission input shaft (10). Electric drive according to one of Claims 1 until 3 , characterized in that the second spur gears (11, 12) of the two spur gear stages (6, 7) assigned to the transfer case (3) are designed as shiftable idler gears which, in the engaged state, are non-rotatably connected to the transfer case (3rd ) are connectable. Electric drive according to one of the preceding claims, characterized in that the first spur gears (8, 9) of the two spur gear stages (6, 7) are each mounted on the transmission input shaft (10) via axial bearings (16, 17). Electric drive according to one of Claims 1 until 5 , characterized in that the first spur gears (8, 9) of the two spur gear stages (6, 7) are each mounted on the axial side of the transmission input shaft (10) via pressure collars (18, 19). Electric drive according to one of Claims 4 until 7 , characterized in that a form-fitting switching element is provided as the switching element (13). Electric drive according to one of Claims 4 until 8th , characterized in that a frictional synchronization is provided as the switching element (13). Electric drive according to one of the preceding claims, characterized in that a spur gear differential gear or a bevel gear differential gear is provided as the transfer gear (3). Vehicle with at least one electric drive according to one of the preceding claims.

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