DE102018130437A1 - Electric drive for a vehicle - Google Patents

Abstract

Electric drives for vehicles usually include an electric motor and a transmission which, depending on the configuration of the transmission, has a translation function, a switching function and / or a distribution function. Due to the different functions, such an electric drive requires a large number of components which interlock in the drive train. The components must be stored in a function-oriented manner, bearing devices, such as rolling element bearing devices, are often used. It is an object of the present invention to propose an electric drive for a vehicle, which is characterized by a functional storage concept. For this purpose, an electric drive 1 for a vehicle with a gear area 6, the gear area 6 being at least a first input sun shaft 15a Ring gear 19, a planet carrier 17 and a plurality of planetary shafts 18, wherein the planetary shafts 18 are rotatably arranged on the planet carrier 17 and the planetary shafts 18 mesh with the first input sun shaft 15a and the ring gear 19, with a housing 2, with a first sun bearing arrangement 24a for mounting the first input sun shaft 15a, the first sun bearing arrangement 24a being designed as a first fixed bearing for absorbing axial and radial forces, with a carrier bearing arrangement 28 for mounting the planet carrier 17 relative to the housing 2, the carrier bearing arrangement 28 for axial bearing Inclusion of axial forces, proposed, the carrier bearing arrangement 28 comprises a radial centering bearing 30 for radial pre-centering of the planet carrier 17 with radial play.

Description

The invention relates to an electric drive for a vehicle with the features of the preamble of claim 1.

Electric drives for vehicles usually include an electric motor and a transmission which, depending on the configuration of the transmission, has a translation function, a switching function and / or a distribution function. Due to the different functions, such an electric drive requires a large number of components which interlock in the drive train. The components must be stored in a functional manner, often using bearing devices, such as rolling element bearing devices.

An example of such an electric drive is the DE 10 2011 007 253 A1 given, which probably forms the closest state of the art. This shows an electric drive, the electric motor and the transmission being arranged coaxially to one another. The output shafts are also arranged coaxially, one of the output shafts being carried out by the electric motor. The individual components are largely stored by roller bearing devices.

It is an object of the present invention to propose an electric drive for a vehicle, which is characterized by a functional storage concept. This object is achieved by an electric drive for a vehicle with the features of claim 1. Preferred or advantageous embodiments of the invention result from the subclaims, the following description and the attached figures.

The invention relates to an electric drive which is suitable and / or designed for a vehicle. The vehicle is, for example, a car, truck or bus, etc. Alternatively, the vehicle can also be designed as a two-wheeler or as a three-wheeler. The vehicle can be designed as a hybrid vehicle, but it is particularly preferably designed as a purely electric vehicle, with the electric drive providing the main drive torque for the vehicle. The electric drive is particularly preferably designed as an electric axle with two output shafts, the two output shafts being arranged coaxially to one another and each being operatively connected to a driven wheel of the vehicle in order to drive it.

The electric drive has a transmission area, the transmission area with its main components defining a main axis. The transmission area has at least a first input sun shaft, a ring gear, a planet carrier and a plurality of planet shafts. The input sun shaft is arranged coaxially to the main axis H. The planetary shafts are rotatably arranged on the planet carrier, but spaced apart from the main axis H in a common pitch circle diameter by the respective own axis of rotation. The planetary shafts are in meshing engagement with the first input sun shaft, and the planetary shafts are in meshing engagement with the ring gear. For this purpose, the planet shafts have at least one planet gear section. For this purpose, the first input sun shaft has at least one first sun gear section. The ring gear preferably has internal teeth for meshing engagement with the planetary shaft.

The electric drive has a housing which can be formed in one or more parts. In particular, the ring gear is arranged stationary in the housing.

The electric drive has a first sun bearing arrangement for mounting the first input sun shaft, the first input sun shaft being mounted rotatably about the main axis H. The first sun bearing arrangement is designed as a first fixed bearing for absorbing axial and radial forces. The sun bearing arrangement preferably supports the first input sun shaft with respect to the housing, in particular in the radial and axial directions. The sun bearing arrangement and / or the first fixed bearing is preferably designed as a rolling element bearing.

The electric drive also has a carrier bearing arrangement for mounting the planet carrier relative to the housing. The carrier bearing arrangement has an axial bearing for absorbing axial forces. In particular, the axial forces are derived from the planet carrier via the axial bearing in the housing. The axial bearing is particularly preferably designed as a rolling element bearing.

Within the scope of the invention, it is proposed that the carrier bearing arrangement have a radial centering bearing for radial pre-centering of the planet carrier, the radial centering bearing preferably holding the planet carrier with radial play. The radial centering bearing therefore has the task of radially pre-centering the planet carrier in the passive and / or inoperative state, the radial centering bearing preferably becoming inoperative during operation. As an alternative or in addition, it is provided that the axis of rotation of the planet carrier can freely adjust in the radial direction during operation.

It is a consideration of the invention that a drive train of the electric drive must be mounted in such a way that the individual components can align themselves in a loaded state. The invention provides that the at least one first input sun shaft is fixedly mounted in the radial and axial directions, in particular in such a way that the at least one first input sun shaft rotates without tolerance and / or without play. The planet carrier, on the other hand, is only and / or exclusively pre-centered in the load-free case, so that the planet carrier is radially free, the planetary gear formed by the input sun shaft, the ring gear and the planet carrier centering itself under load and thus for optimal load distribution on the toothing and in the gearbox.

In a preferred embodiment of the invention, it is provided that the planet carrier is not supported in the radial centering bearing during operation and / or can move radially freely.

In a preferred constructional configuration, the radial centering bearing comprises a slide bearing device, the planet carrier being supported with the radial play via the slide bearing device. The radial play is preferably greater than 0.1 mm, in particular greater than 0.2 mm.

In a preferred implementation of the invention, the first sun bearing is designed as a radial-axial roller bearing device for mounting the first input sun shaft relative to the housing. In particular, the radial-axial roller bearing device is designed as a double angular contact ball bearing, the double angular contact ball bearing being supported with an outer ring on the housing or on a housing section of the housing. The radial-axial roller bearing device is particularly preferably arranged centrally and / or centrally with respect to the axial direction on the first input sun shaft.

In one possible development of the invention, the electric drive has a second input sun shaft and a second sun bearing arrangement. The second input sun wave is arranged coaxially and / or concentrically to the first input sun wave. In particular, the first and / or the second input sun shaft is each designed as a hollow shaft. The planetary waves mesh with the second input solar wave. The second sun bearing arrangement is designed as a second fixed bearing for absorbing axial and radial forces. As an alternative or in addition, the second input sun shaft is thus guided in the axial and radial directions without tolerance and / or without play.

In a preferred implementation of the invention, the second sun bearing arrangement comprises a radial roller bearing device for mounting the second input sun shaft relative to the first input sun shaft. For example, the radial roller bearing device is designed as a radial needle bearing. Furthermore, the second sun bearing arrangement has an axial bearing device and / or an axial-radial bearing device for mounting the second input sun shaft relative to the housing and / or to the tarpaulin carrier. In particular, the second input sun shaft is supported with respect to the housing and / or to the planet carrier with said bearing device in the axial direction. For example, the axial bearing device is designed as a four-point bearing, which can additionally transmit radial forces. The decisive point here, however, is that the second input sun shaft is supported in the axial direction without tolerance and / or without play.

In a preferred development of the invention, the electric drive has an electric motor with a rotor shaft. The electric motor is preferably designed as an inner rotor. Furthermore, the electric drive has a clutch section, the clutch section being arranged in the torque flow between the rotor shaft and the first input sun shaft and transmitting a drive torque from the electric motor in the direction of the planetary gear. It is provided that the coupling section decouples the rotor shaft from the first input sun shaft in the radial and / or axial direction. For example, the clutch section has a lamella section, the lamella input side as the clutch input being displaceable in the axial direction and in the radial direction as a clutch output from the disk output side, so that mechanical decoupling is formed from the rotor shaft to the first input sun shaft. In the event that the electric drive has the second input sun shaft, there is also a decoupling between the rotor shaft and the second input sun shaft in the radial and / or axial direction in the same way.

It is particularly preferred that the rotor shaft is mounted on a fixed-loose bearing. It is provided that the fixed bearing is formed on the gear side of the rotor shaft, the fixed bearing being designed, for example, as an axial-radial ball bearing. In contrast, it is preferred that the floating bearing is arranged on the side of the rotor shaft facing away from the transmission and is formed, for example, by a radial ball bearing. In this embodiment, the side of the rotor shaft, which faces the transmission, is fixedly mounted, so that only small tolerances are introduced here. The rotor shaft can compensate for the tolerances on the other hand, freely adjust on the opposite side for batch storage.

In a preferred embodiment of the invention, the coupling section has at least one first coupling output, the first coupling output being connected to the first input sun shaft in a rotationally fixed and non-displaceable manner. This preferably rigid coupling between the coupling output and the first input sun shaft is possible since the coupling section mechanically decouples the coupling output and the rotor shaft from one another.

In a preferred development of the invention, the coupling section has a second coupling output, the second coupling output being connected to the second input sun shaft in a rotationally fixed and displaceable manner. Here, too, there is preferably a rigid coupling between the second coupling output and the second input sun shaft, the rigid coupling being made possible by the coupling section performing the decoupling function.

In a preferred development of the invention, the coupling section has a coupling input, the coupling input being connected in a rotationally fixed and displaceable manner to the rotor shaft. Thus there is a rigid connection to the rotor shaft on the input side of the coupling section and a rigid connection to the first / or the second input sun shaft on the output side of the coupling section. The coupling section provides the decoupling between the two rigid sections.

In other words, the object of the invention can have some or all of the following features: The rotor of the electric torch is mounted in a classic fixed-lot bearing. The left bearing is the floating bearing and the right bearing is the fixed bearing, designed as a ball bearing. The fixed bearing for the rotor is also the fixed bearing for the double clutch. The power flow goes from the actuator via the double clutch, via a locking ring at the splines to the fixed bearing. The two output sides of the double clutch are supported by the splines on the two input sun shafts. The plate packs themselves allow compensation in the radial direction. The outer and / or first input sun shaft is fixed to the housing via a double angular contact ball bearing. The inner and / or second input sun shaft is supported radially via a needle bearing on the outer input sun shaft. The axial forces of the inner sun shaft are derived on the right side via a 4-point bearing in the planet carrier. The planet carrier is axially supported on the left and right, each with an axial needle bearing. As a result, the axial forces occurring in the transmission are diverted into the housing via the planet carrier. The planet carrier is not supported radially. Only two plain bearing bushes ensure pre-centering in a load-free case. The ring gear is firmly connected to the housing by means of splines and a locking ring. Since both the input sun shafts and the ring gear are fixed and the planet carrier is radially free, the entire planetary gear can center itself under load and thus ensures optimal load distribution on the teeth and in the gear.

• 1 einen schematischen Längsschnitt durch einen elektrischen Antrieb für ein Fahrzeug als ein Ausführungsbeispiel der Erfindung.

Further features, advantages and effects of the invention result from the following description of a preferred embodiment and the attached figure. This shows:

• 1 a schematic longitudinal section through an electric drive for a vehicle as an embodiment of the invention.

The 1 shows a schematic longitudinal section of an electric drive 1 as an embodiment of the invention, which is designed as an electrical axle for a vehicle, in particular for an electric vehicle or a hybrid vehicle. The electric drive 1 is used to drive the vehicle and provides a main drive torque.

The electrical output 1 has a housing 2nd on where the components of the electric drive 1 are arranged. Furthermore, the electric drive 1 two output shafts 3rd a , b on, the output shafts 3rd a , b arranged coaxially to one another and to a main axis H. The output shafts 3rd a , b are preferably operatively connected to the driven wheels of an axle of the vehicle.

The electric drive 1 has an engine area 4th , a switching range 5 as well as a gearbox area 6 on. In the engine area 4th is an electric motor 7 arranged, the electric motor 7 a stator 8th and a rotor 9 has, wherein the rotor 9 is arranged coaxially to the main axis H. The rotor 9 is non-rotatable with a rotor shaft 10th connected, the rotor shaft 10th is designed as a hollow shaft and the output shaft 3rd a through the rotor shaft 10th is carried out.

The switching range 5 has a coupling section 11 on, the coupling section 11 as a double clutch 12 is formed with an actuator. The coupling section 11 has a clutch input 13 and two clutch outputs 14 a , b on. The coupling section 11 , especially the double clutch 12 is designed as a multi-plate clutch, one of the plate packs with the clutch input 13 and one each Another plate pack with the clutch outputs 14 a , b are connected.

The transmission area 6 exhibits a first input solar wave 15a and a second input sun wave 15 b on. The input sun waves 15 a , b are each designed as hollow shafts and arranged concentrically and / or coaxially to one another and to the main axis H. The first input sun wave 15 a is non-rotatable with the first clutch outlet 14 a , the second input solar wave 15 b is non-rotatable with the clutch outlet 14 b connected so that a drive torque from the electric motor 7 about the rotor shaft 10th , the coupling section 11 optionally to the first input solar wave 15a or to the second input solar wave 15b can be directed.

The transmission area 6 also has a planetary gear 16 on, the planetary gear 16 a planet carrier 17th includes. In on the planet carrier 17th are multiple planetary waves 18th arranged, the planetary waves 18th are arranged parallel to the main axis H on a common pitch circle diameter around the main axis H. The planetary waves 18th comb both with the first input solar wave 15a as well as with the second input solar wave 15b . The planetary waves also comb 18th with a stationary ring gear 19th so that when the input sun shaft rotates 15 a or 15 b the planetary wave 18th is rotated and over the ring gear 19th expires so that the planet carrier 17th is rotated.

On the planet carrier 17th are also two sets of output planet gears 20th a , b arranged with a first set of output planet gears 20th a with a first exit sun gear 21 a and a second set of output planet gears 20th b with a second output sun gear 21 a comb. Furthermore, the output planet gears mesh 20th a , b in pairs with each other. The exit sun gears 21 a , b are each with one of the output shafts 3rd a , b non-rotatably connected, so that the drive torque can be directed to the driven wheels.

On closer inspection, the first input solar wave points 15 a a first sun gear section 22 a and the second input sun wave 15 b a second sun gear section 22 b on. The planetary wave 18th each has a first planet gear section 23 a on, the first planetary gear section 23a with the first sun gear section 22 a combs. Furthermore, the planetary wave 18th a second planet gear section 23 b on, the second planet gear section 23 b with the second sun gear section 22 b comb. Furthermore, the planetary wave 18th a third planet gear section 23 c on, the third planetary gear section 23 c with the ring gear 19th comb. The planet gear section 23 a , b , c are rotatably arranged to each other.

The first input sun wave 15 a is about a first sun bearing arrangement 24th a directly opposite the housing 2nd stored. The first sun bearing arrangement 24th a is designed as a radial axial bearing and designed as a roller bearing. From a functional point of view, the first sun bearing arrangement forms 24th a a fixed bearing, which from the first input solar wave 15 a absorbs both axial and radial forces during operation. In particular, the first input sun wave 15 a about the first sun bearing arrangement 24th a Tolerance-free and / or backlash-free in radial and axial direction. The first input sun wave 15 a is thus designed as a fixed sun. The first sun bearing arrangement 24th a is designed as a double angular contact ball bearing, the double angular contact ball bearing being located radially on the inside on the first input sun shaft 15 a and radially outside on a wall section 25th supports, the wall section 25th with the housing 2nd is screwed tight or forms a section of this. The wall section 25th separates the switching range 5 from the gearbox area 6 .

The second input sun wave 15 b is about a second sun bearing arrangement 24th b indirectly against the housing 2nd stored. The second sun bearing arrangement 24th b is designed as a radial axial bearing and designed as a roller bearing. From a functional point of view, the second sun bearing arrangement also forms 24th b a fixed bearing from the second input sun shaft 15 b absorbs both axial and radial forces during operation. In particular, the second input sun wave 15 b about the second sun bearing arrangement 24th b Tolerance-free and / or backlash-free in radial and axial direction. The second input sun wave 15 b is thus designed as a fixed sun.

The second sun bearing arrangement 24th b includes a radial bearing 26 , which is realized as a roller bearing, the radial bearing 26 between the first and second input solar waves 15 a , b is arranged. The radial bearing is supported on the radial inside 26 on the second input solar wave 15 b and the radial bearing is supported on the radial outside 26 on the first input solar wave 15 a and thus about the first sun bearing arrangement 24th a indirectly on the housing 2nd from. The radial bearing 26 is designed as a radial needle bearing.

The second sun bearing arrangement 24th b also includes a thrust bearing 27th and executed in this embodiment as an axial-radial bearing, which is realized as a roller bearing. The axial bearing is supported on the radial inside 27th on the second input solar wave 15 a the on which the axial bearing is supported on the radial outside 27th on the planet carrier 17th from which is fixed in the axial direction, in particular tolerance-free and / or free of play. This supports the thrust bearing 27th about the planet carrier 17th and its storage indirectly on the housing 2nd tolerance-free and / or play-free in the axial direction. The thrust bearing 27th is designed as a four-point bearing. The thrust bearing 27th must have an axial bearing component and can optionally additionally include a radial bearing component as in this exemplary embodiment.

The planet carrier 17th is about a carrier bearing arrangement 28 towards the housing 2nd stored. The carrier bearing arrangement 28 has an axial bearing to absorb axial forces from the planet carrier 17th the housing 2nd be directed. The axial bearing supports the planet carrier 17th in the axial direction without play and / or tolerance-free. The axial bearing has a first and a second axial bearing 29 a , b on, which are designed in this embodiment as an axial needle bearing. The first thrust bearing 29 a is supported with the axial outside on the wall section 25th and thus on the housing 2nd and with the axial inside on the planet carrier 17th from. The second thrust bearing 29 b is supported on the housing with the axial outside 2nd and with the axial inside on the planet carrier 17th from.

The carrier bearing arrangement 28 has a radial centering 30th on which has the function of the planet carrier 17th radially pre-center at standstill, but in operation the planet carrier 17th to enable its axis of rotation to adjust freely in the radial direction. The position and orientation of the axis of rotation is determined by the interaction of the fixed input sun shafts 15 a , b , the stationary ring gear 19th and the freely adjustable planet carrier 17th automatically and thus in particular tension-free and / or adjusted to the load. The radial centering bearing 30th is by two plain bearing devices 31 a , b formed, which are realized as plain bearing bushes. The plain bearing devices 31 a , b are aligned coaxially to the main axis H. The first plain bearing device 31 a is between the wall section 25th and the planet carrier 17th arranged, the second plain bearing device 31 b is between the case 2nd and the planet carrier 17th arranged. The radial centering bearing 30th holds the planet carrier 17th relative to the housing 2nd with clearance, the clearance preferably being greater than 0.1 mm, in particular greater than 0.2 mm, so that the planet carrier 17th relative to the housing 2nd can move in a maximum deflection in a first radial direction and in the opposite direction to said amount.

The rotor shaft 10th is about a fixed-lot storage 32 stored which is a floating bearing 33 has, which is designed as a radial ball bearing and on the coupling section 11 opposite side of the rotor shaft 10th is arranged. Furthermore, the fixed lot storage 32 a fixed camp 34 on, which is designed as an axial-radial ball bearing and on the coupling section 11 facing side of the rotor shaft 10th is arranged.

From a functional point of view, the rotor shaft can 10th about fixed-lot storage 32 set freely. Via the coupling section 11 is the rotor shaft 10th with regard to the radial and / or axial position of the input sun waves 15 a , b decoupled, since the plates from the clutch input 13 and the clutch outputs 14 a , b be able to position relative to each other according to the load.

The planet carrier 17th can by the radial centering 30th free in the radial direction compared to the input sun waves 15 a , b and the ring gear 19th set freely. This is for the electric drive 1 a consistent storage concept along the entire drive train of the electric motor 7 to the output shafts 3rd a , b educated.

Reference symbol list

1

electric drive

2nd

casing

3a, b

Output shafts

4th

Engine range

5

Switching range

6

Transmission area

7

Electric motor

8th

stator

9

rotor

10th

Rotor shaft

11

Coupling section

12th

Double coupling

13

Clutch input

14a, b

Coupling outputs

15a, b

Input solar wave

16

Planetary gear

17th

Planet carrier

18th

Planetary waves

19th

Ring gear

20a, b

Home planet wheels

21a, b

Exit sun gears

22a, b

Sun gear section

23a, b, c

Planet gear section

24a, b

Sun bearing arrangement

25th

Wall section

26

Radial bearing

27th

Thrust bearing

28

Carrier bearing arrangement

29a, b

Thrust bearing

30th

Radial centering

31 a, b

Plain bearing devices

32

Fixed-lot storage

33

Floating bearing

34

Fixed camp

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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 102011007253 A1 [0003]

Claims (10)

Electric drive (1) for a vehicle, with a transmission area (6), the transmission area (6) having at least a first input sun shaft (15a), a ring gear (19), a planet carrier (17) and a plurality of planet shafts (18) , wherein the planet shafts (18) are rotatably arranged on the planet carrier (17) and the planet shafts (18) mesh with the first input sun shaft (15a) and the ring gear (19), with a housing (2), with a first sun bearing arrangement ( 24a) for mounting the first input sun shaft (15a), the first sun bearing arrangement (24a) being designed as a first fixed bearing for absorbing axial and radial forces, with a carrier bearing arrangement (28) for mounting the planet carrier (17) relative to the housing (2 ), the carrier bearing arrangement (28) comprising an axial bearing for absorbing axial forces, characterized in that the carrier bearing arrangement (28) has a radial centering bearing (30) for radial precentering tion of the planet carrier (17) with radial play. Electric drive (1) after Claim 1 , characterized in that the planet carrier (17) is not supported in operation in the radial centering bearing (30). Electric drive (1) after Claim 1 or 2nd , characterized in that the radial centering bearing (30) has a slide bearing device (31a, b), the planet carrier (17) being mounted with the radial play via the slide bearing device (30a, b). Electric drive (1) according to one of the preceding claims, characterized in that the first sun bearing arrangement (24a) is designed as a radial-axial roller bearing device for mounting the first input sun shaft (15a) relative to the housing (2). Electric drive (1) according to one of the preceding claims, characterized in that the electric drive (1) has a second input sun shaft (15b) and a second sun bearing arrangement (24b), the second input sun shaft (15b) coaxial and / or concentric to the the first input sun shaft (15a) is arranged, the planetary shafts (18) meshing with the second input sun shaft (15) and the second sun bearing arrangement (24b) being designed as a second fixed bearing for absorbing axial and radial forces. Electric drive (1) after Claim 5 , characterized in that the second sun bearing arrangement (24b) has a radial roller bearing device (26) for mounting the second input sun shaft (15b) relative to the first input sun shaft (15a) and an axial and / or axial radial bearing device (27) for mounting the second input sun shaft (15b ) relative to the housing (2) and / or to the planet carrier (17). Electric drive (1) according to one of the preceding claims, characterized by an electric motor (7) with a rotor shaft (10) and with a coupling section (11), the coupling section (11) between the rotor shaft (10) and the first input sun shaft (15a ) is arranged, the coupling section (15a) decoupling the rotor shaft (10) from the first input sun shaft (15a) in the radial and / or axial direction. Electric drive (1) after Claim 7 , characterized in that the rotor shaft (10) is mounted on a fixed-floating bearing (32). Electric drive (1) after Claim 7 or 8th , characterized in that the coupling section (11) has at least a first coupling output (14a), the first coupling output (14a) being connected to the first input sun shaft (15a) in a rotationally fixed and non-displaceable manner. Electric drive (1) according to one of the Claims 7 to 9 characterized in that the coupling section (11) has a coupling input (13), the coupling input (13) being connected to the rotor shaft (10) in a rotationally fixed and non-displaceable manner.

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