DE102011005621A1 - Drive device for driving a wheel of a suspension strut axle for an electrically driven vehicle - Google Patents

Abstract

The invention relates to a drive device (1) for driving a wheel (2) of a suspension strut axle for an electrically drivable vehicle, comprising an electrical machine (3) and a transmission (4, 5) connected on the output side of the electrical machine (3) when viewed in the direction of the flow of force during train operation. , in which the housing (10) of the electrical machine (12) or the housing (11) of the transmission (4, 5) is screwed directly to the wheel carrier (8) of the vehicle axle, integrated as a multi-part welding component in the wheel carrier (8) or are made in one piece with the wheel carrier (8).

Description

The present invention relates to a drive device for driving a wheel of a suspension strut axle for an electrically driven vehicle according to the preamble of patent claim 1.

In general, the arrangement of the drive train in electrically driven vehicles corresponds to the arrangement of the drive train in vehicles having a central drive, comprising an internal combustion engine. Here, a drive device comprising an electric machine, a transmission and a differential is fixed to the body in the center of the vehicle between the front or rear wheels arranged; The output torque is transmitted via side shafts to the driven wheels as in conventional central drives. In such an arrangement of the drive train, the suspension concept remains largely intact, with only modifications of the unit mounting and the subframe are required.

In electrically driven or driven vehicles, comprising a central drive, the battery housing represents a significant intervention in the vehicle structure. It is known, the battery in the subsoil, for example, under the rear seat or in the area was taken in central drives with an internal combustion engine from the transmission tunnel , to integrate.

Radnahe electrical drives are also known in the prior art, being understood by near-wheel electrical drives hereinafter drives, which provide one or more electric motors per drive wheel of the vehicle. Thus, vehicles with two or more drive wheels are known, which have a corresponding number of drives, so two or more. In each case, an electric motor can act on exactly one drive wheel.

Under close to the wheel drives but also drives can be understood that have a handlebar fixed or a wheel-fixed drive.

Furthermore, known from the prior art radnahe electric drives for driving a wheel of a driven axle for electrically driven vehicles, which are integrated into the chassis of the vehicle, wherein, depending on the number of driven vehicle axles, for example, two or four electric drives are provided ,

Here, the electric drives can be arranged Radträgerfest; In this case, the electric drive springs directly with the respective wheel and the unsprung mass is directly influenced by the drive.

Another way of arranging the near-wheel electrical drives is to arrange this construction test. Here, the electric drives move out of the vehicle center out towards the wheels. In this case, the drives can be attached to the structure, whereby an influence on the unsprung mass is prevented.

Further, the electric drives can be arranged handlebar fixed, in which case they are attached to the suspension arms, for example, the composite beam. This design reduces the unsprung mass by locating the electric drives close to the most advanced linkage point.

From the DE 10 2007 039 059 A1 The applicant is known as a driven axle which is designed as a torsion beam axle, in which an electric motor is provided for each wheel of the axle, which is arranged with the axis of rotation in the vehicle longitudinal direction, the housing of which forms part of the longitudinal arm of the torsion beam axle.

Radnahe drives may be provided in vehicles with all-wheel, front or rear wheel drive, the axle types of the driven vehicle axles conventional axle types, such. B. strut or double wishbone axles can be. Furthermore, wheel-near drives can be integrated into wheel-integrated running gears.

Furthermore, the wheel-near electric drives for driving a wheel of an axle for an electrically driven vehicle may have a transmission.

From the EP 1 961 602 A1 For example, there is known a drive apparatus for driving the wheel which can be integrated into a vehicle wheel and which has an electric motor and two planetary gears connected in series, which are arranged axially between the electric motor and the wheel.

Advantageously, the use of radnahen electrical drives for driving a wheel of a driven axle results in the vehicle body in a high flexibility, since the elimination of the central drive in the vehicle center new degrees of freedom in the vehicle design, especially in the design of the vehicle interior, the battery housing and crash safety.

In addition, wheel-specific electric drives can generate wheel-specific drive torques, as a result of which functions such as torque vectoring, ESP, ABS, ASR, etc. can be easily implemented. The fast and more accurate controllability of electric drives enables these functions to be optimized compared to conventional brake-based control systems.

The present invention has for its object to provide a drive device for driving a wheel of a strut axis for an electrically driven vehicle.

This object is solved by the features of patent claim 1. Further embodiments and advantages of the invention will become apparent from the dependent claims.

Accordingly, a drive device for driving a wheel of a shock absorber axle for an electrically driven vehicle is proposed, comprising an electric machine and a viewed in the direction of force flow in the train operation on the output side of the electric machine switched gear, the housing of the electric machine or the housing of the transmission directly to the wheel connected to the strut axis, preferably screwed, integrated as a multi-part welding component in the wheel or executed in one piece with the wheel. As part of a development, the electric machine and the transmission may have a common housing.

The drive device can be arranged coaxially to the wheel axle. In addition, the housing of the electric machine or the housing of the transmission can be inserted as a prefabricated unit axially in the wheel carrier, which serves in this case as an overall housing. For this purpose, two end shields of the electric machine together with an axially compressed laminated stator core can serve as an auxiliary housing.

Also, a speed and / or angle sensor may be disposed on the motor shaft of the electric machine to detect the rotational speed and / or the angle of the motor shaft.

Preferably, the arrangement of the electric machine and the transmission is such that in the predominant operating position of the vehicle, the lubricant automatically flows back under the action of gravity from the electric machine in the oil sump in the gear compartment, for which purpose the housing of the electric machine is designed such that a sufficient lubrication of the bearings of the rotor shaft is ensured. This results in the advantage of eliminating the need to provide contacting or non-contacting seals, particularly with high speed shafts of the drive device, thereby reducing heat buildup and power losses.

In a further development of the invention, the connection of the wheel associated caliper and / or damper and / or spring of the strut axis are integrated into a housing of the drive device, wherein the connecting screws for fixing the caliper can simultaneously represent housing screws for mounting the drive device on the wheel ,

In this way, a compact design is achieved and eliminates the need for separate components, resulting in a reduction in costs.

Preferably, the electric machine is high-revving, wherein the transmission has a high gear ratio, resulting in a high power / weight ratio (kW / kg) of the drive device and a small size of the electric machine.

A translation is understood here as the ratio of the rotational speed of the output shaft of the transmission to the rotational speed of the drive shaft of the transmission. A high ratio is understood to mean a ratio greater than 1:10, preferably 1:10 to 1:20, particularly preferably 1:14 to 1:18, in particular 1:16.

A high-speed machine is understood to mean a machine which has a maximum rotor speed of more than 15,000 revolutions / minute, preferably between 19,000 and 25,000 revolutions per minute.

The gearbox connected on the output side of the electric machine preferably comprises two planetary gearboxes connected in series.

Due to the two planetary gear a large translation is possible, thereby the dimensions and the weight of the electric machine can be kept low; For example, the achievable by the two planetary gear ratio, so the ratio of the rotational speed of the drive shaft of the transmission to the output shaft of the transmission, assume a value which is between 10 and 30, wherein the division of the achievable gear ratio is symmetrical or asymmetrical on the planetary gear.

Advantageously, the combination of a low drive torque with a high speed utilization in combination with the two planetary gears of the drive device results in a high power / weight ratio (kW / kg). The electrical machine can thereby be dimensioned small, which allows or simplifies the integration of the electric machine in the wheel carrier.

Also, the drive device for driving a wheel of a strut axle for an electrically driven vehicle may be characterized in that the connecting screws for fixing the brake caliper of the disc brake at the same time housing screws for fastening the drive device on the wheel ( 8th ).

The considered in the power flow direction in the train operation on the drive side of the electric machine connected transmission can also be designed as a planetary gear, spur gear or as a combination of a planetary gear with a spur gear or with a bevel gear.

The invention will be explained in more detail below with reference to the accompanying figures, wherein the same reference numerals are used for the same components. Show it:

1 : A schematic view of the arrangement of an inventively designed drive device; and

2 : A schematic sectional view of part of a suspension strut axle comprising a drive device according to the invention.

Referring to 1 includes a drive device 1 to drive a wheel 2 a strut axis of an electrically driven vehicle an electric machine 3 and two viewed in the direction of force flow in traction on the output side of the electric machine 3 connected in series planetary gear 4 . 5 , The first and the second planetary gear 4 . 5 are in the example shown on the wheel 2 facing side of the electric machine 3 arranged. In the figure, the damper of the strut axis is denoted by the reference numeral 6 provided with, with 7 the wishbone and with 8th the wheel carrier is designated.

How out 1 seen, is the drive device 1 coaxial to the wheel axle 9 arranged. According to the invention, the housing 10 the electric machine 3 or the housing 11 the planetary gear 4 . 5 directly with the wheel carrier 8th connected to the strut axis, preferably screwed, as a multi-part welding component in the wheel 8th integrated or with the wheel carrier 8th made in one piece.

Here, the rotor is preferably designed as an internal rotor electrical machine 3 over a wave 12 with the sun wheel 13 of the first planetary gear 4 rotatably connected, the web 14 of the first planetary gear 4 about another wave 15 with the sun wheel 16 of the second planetary gear 5 rotatably connected. The output of the drive device 1 via the footbridge 17 of the second planetary gear 5 and one with the jetty 17 rotatably connected shaft 18 connected with the wheel hub of the wheel 2 rotatably connected.

Furthermore, the ring gear 19 of the first planetary gear 4 and the ring gear 20 of the second planetary gear 5 fixed to the housing; they can attach to the case 11 the planetary gear 4 . 5 the drive device 1 coupled, integral with the housing 11 executed or in the housing 11 be pressed. In the event that a ring gear is integral with the housing 11 is executed, a radial shoulder may be provided to a diameter difference between the housing 11 and compensate the ring gear.

Due to the configuration of a ring gear as einpressbarer in a cylindrical housing Hohlradring can be selected depending on the load of the material, and this can result in a reduction in weight.

As part of a development, the rotor of the electric machine 3 integral with the shaft 12 Be carried over which the rotor with the sun gear 13 of the first planetary gear 4 connected is; Furthermore, the wave 15 over which the jetty 14 of the first planetary gear 4 with the sun wheel 16 of the second planetary gear 5 rotatably connected, with the bridge 14 of the first planetary gear 4 be executed in one piece.

The gears of the planetary gear 4 . 5 are preferably helical teeth, wherein the connection between the web 14 of the first planetary gear 4 with the sun wheel 16 of the second planetary gear 5 axially and radially supported by rolling bearings, plain bearings or thrust washers.

Here is the helix angle of the sun gear 13 of the first planetary gear 4 opposite to the helix angle of the sun gear 16 of the second planetary gear 5 , In addition, advantageously, the directions of the helix angles of the sun gear 13 of the first planetary gear 4 and the sun wheel 16 of the second planetary gear 5 to choose so that the loads on the bearings of the drive device 1 , in particular on the bearings of the shaft 12 over which the rotor with the sun gear 13 of the first planetary gear 4 is minimized. As a result, the friction losses are minimized and it is possible a smaller dimensioning of the bearings.

The bearing of the shaft 12 over which the rotor with the sun gear 13 of the first planetary gear 4 is connected, falls according to an embodiment of the invention with the drive-side mounting of the rotor of the electric machine 3 together, eliminating the need for separate bearings, taking the sun gear 13 of the first planetary gear 4 remote storage of the rotor of the electric machine 3 may preferably be biased axially by a spring element.

Furthermore, according to a development of the invention, at least one bearing side of the web with the web 17 of the second planetary gear 5 connected shaft 18 , ie the output of the drive device 1 , through the wheel bearing of the wheel 2 formed, which can be designed as a bearing of conventional design, for example, as a double-row roller bearing or bearing comprising two Einzelschrägrollenlager with a pressure angle between 15 ° and 60 °. This can advantageously the number of bearings of the drive device 1 be reduced.

The connection of the bridge 17 of the second planetary gear 5 connected shaft 18 with the wheel hub of the wheel 2 can be done by means of a plug-in splined connection or a polygonal profile; Alternatively, that of the drive device 1 opposite end of the bridge 17 of the second planetary gear 5 rotatably connected shaft 18 represent the wheel hub itself, whereby the assembly and manufacturing costs are reduced. According to the invention, the provision of an additional, cylindrical fitting connection between the wheel hub and the shaft is also provided 18 for better centering of the shaft 18 possible.

As part of a development of the invention, it is provided that the electric machine 3 and the planetary gears 4 . 5 have a common housing, in which case the two end shields of the electric machine 3 together with the axially compressed stator plate can form an auxiliary housing, which is axially insertable as a kind of cartridge in the prefabricated housing of the drive device.

2 FIG. 3 shows a further view of a part of a strut axle comprising a drive device according to the invention. FIG 1 in this 2 are the rotor of the electric machine 3 with the reference number 21 and the stator by the reference numeral 22 designated. Furthermore, a wishbone 23 , a stabilizer 24 , the tie rod 25 and a disc brake 26 shown.

The housing 10 the electric machine 3 is in the example shown directly to the wheel 8th the strut axis connected. As part of a development of the invention, not shown, the connection of the caliper of the disc brake 26 and / or the damper 6 and / or the spring in the housing 11 the planetary gear 4 . 5 or in the case 10 the electric machine 3 the drive device 1 integrated, wherein the connecting screws for fixing the caliper at the same time housing screws for fastening the drive device 1 on the wheel carrier 8th can represent.

In this way, a compact design is achieved and eliminates the need for separate components, resulting in a reduction in costs.

In an unillustrated embodiment of the invention, the electric machine 3 as a hollow shaft motor, ie as an electric machine with a designed as a hollow shaft rotor 21 be executed, wherein the first and the second planetary gear 4 . 5 at the wheel 7 opposite side of the electric machine 3 are arranged and the output shaft of the drive device 1 that by the with the jetty 17 of the second planetary gear 5 rotatably connected shaft 18 is formed, through the cavity of the rotor 21 the electric machine 3 to the wheel 1 is guided, for example, where it is preferably connected via a conventional spline profile with the wheel hub or the wheel hub itself, as already explained.

Here, at the end remote from the electric machine of the drive device 1 another storage (a first storage is through the wheel bearing of the wheel 1 formed, as already explained) with the web 17 of the second planetary gear 5 rotatably connected shaft 18 provided, preferably on a journal of the shaft 18 is arranged.

By interchanging the arrangement of the electric machine 3 and the first and second planetary gear 4 . 5 compared to the embodiment according to 1 and 2 the advantage is achieved that space is provided, which is used during compression, as the housing 11 of the first and second planetary gear 4 . 5 smaller outer diameter is executable as the housing of the electric machine 3 , Furthermore, the connection between the electric machine 3 and the wheel hub are carried out less stiff than in the execution according to 1 and 2 ,

The electric machine of the drive device can be designed as an asynchronous machine, as a third-excited or permanent magnet-excited synchronous machine or as a cross-field machine, which offers a high degree of flexibility.

Due to the design according to the invention, a very compact design of the drive device can be realized with a low unsprung mass and high power / weight ratio (kW / kg).

Furthermore, the drive device has a low number of bearings and good accessibility, and it can be integrated into the axle with little modification of an existing vehicle axle.

Further, the braking device of the wheels may be designed as a disc brake or drum brake; The drive device may be air-cooled or fluid-cooled, wherein the electric machine, the transmission and the power electronics may have a common cooling. The power electronics can also be arranged Radträgerfest.

LIST OF REFERENCE NUMBERS

1

driving device

2

wheel

3

electric machine

4

first planetary gear

5

second planetary gear

6

damper

7

wheel carrier

8th

wheel axle

9

Housing of the electric machine 3

10

Housing of the planetary gear 4 . 5

11

wave

12

Sun gear of the first planetary gear 4

13

Bridge of the first planetary gear 4

14

wave

15

Sun gear of the second planetary gear 5

16

Bridge of the second planetary gear 5

17

wave

18

Ring gear of the first planetary gear 4

19

Ring gear of the second planetary gear 5

20

Rotor of the electric machine 3

21

Stator of the electric machine 3

22

wishbone

23

stabilizer

24

tie rod

25

disc brake

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102007039059 A1 [0010]
• EP 1961602 A1 [0013]

Claims (13)

Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, comprising an electric machine ( 3 ) and viewed in the direction of force flow in traction on the output side of the electric machine ( 3 ) switched gear ( 4 . 5 ), characterized in that the housing ( 10 ) of the electric machine ( 12 ) or the housing ( 11 ) of the transmission ( 4 . 5 ) directly with the wheel carrier ( 8th ) bolted to the vehicle axle, as a multi-part welding component in the wheel carrier ( 8th ) or with the wheel carrier ( 8th ) are made in one piece. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically drivable vehicle, according to claim 1, characterized in that the connection of the brake caliper of the disc brake ( 26 ) and / or the damper ( 6 ) and / or the spring in the housing ( 11 ) of the planetary gear ( 4 . 5 ) or in the housing ( 10 ) of the electric machine ( 3 ) of the drive device ( 1 ) are integrated. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of the preceding claims, characterized in that the electric machine ( 3 ) and the transmission ( 4 . 5 ) have a common housing. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of the preceding claims, characterized in that the transmission ( 4 . 5 ) two viewed in the direction of force flow in traction on the output side of the electric machine ( 3 ) connected in series planetary gear ( 4 . 5 ). Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to claim 4, characterized in that the rotor ( 21 ) of the electric machine ( 3 ) over a wave ( 12 ) with the sun wheel ( 13 ) of the first planetary gear ( 4 ) is rotatably connected, that the bridge ( 14 ) of the first planetary gear ( 4 ) about another wave ( 15 ) with the sun wheel ( 16 ) of the second planetary gear ( 5 ) is rotatably connected, that the ring gear ( 19 ) of the first planetary gear ( 4 ) and the ring gear ( 20 ) of the second planetary gear ( 5 ) are fixed to the housing and that the output of the drive device ( 1 ) over the jetty ( 17 ) of the second planetary gear ( 5 ) and one with the bridge ( 17 ) rotatably connected shaft ( 18 ), which is rotatably connected to the wheel hub. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to claim 4 or 5, characterized in that the rotor ( 21 ) of the electric machine ( 3 ) integral with the shaft ( 12 ) is carried out, via which the rotor ( 21 ) with the sun wheel ( 13 ) of the first planetary gear ( 4 ) connected is. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of claims 4 to 6, characterized in that the shaft ( 15 ) over which the bridge ( 14 ) of the first planetary gear ( 4 ) with the sun wheel ( 16 ) of the second planetary gear ( 5 ) is rotatably connected, with the bridge ( 14 ) of the first planetary gear ( 4 ) is made in one piece. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of claims 4 to 7, characterized in that at least one bearing side of the bridge with the bridge ( 17 ) of the second planetary gear ( 5 ) connected shaft ( 18 ), which the output of the drive device ( 1 ), through the wheel bearing of the wheel ( 2 ) is formed. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of claims 4 to 8, characterized in that the connection of the with the web ( 17 ) of the second planetary gear ( 5 ) connected shaft ( 18 ) takes place with the wheel hub by means of a plug-in splined connection or a polygonal profile or that of the drive device ( 1 ) facing away from the end with the bridge ( 17 ) of the second planetary gear ( 5 ) connected shaft ( 18 ) represents the wheel hub itself. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of claims 4, to 9, characterized in that the first and the second planetary gear ( 4 . 5 ) at the wheel ( 2 ) facing side of the electric machine ( 3 ) are arranged. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of claims 4 to 9, characterized in that the first and the second planetary gear ( 4 . 5 ) at the wheel ( 2 ) facing away from the electrical machine ( 3 ), wherein the electric machine ( 3 ) is designed as a hollow shaft motor and the output shaft of the drive device ( 1 ), which by the with the bridge ( 17 ) of the second planetary gear ( 5 ) rotatably connected shaft ( 18 ) is formed by the cavity of the rotor ( 21 ) of the electric machine ( 3 ) to the wheel ( 2 ) to be led. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle, according to at least one of the preceding claims, characterized in that the electric machine is high-revving, preferably a maximum speed greater than 5000 revolutions / min, in particular between 6000 and 10000 revolutions / min, more preferably around 7000 Revolutions / min. Drive device ( 1 ) to drive a wheel ( 2 ) of a strut axle for an electrically driven vehicle according to at least one of the preceding claims, characterized in that the transmission has a ratio, wherein the ratio between the rotational speed of the drive shaft to the output shaft of the transmission greater than 10, preferably between 13 and 17, in particular by 16 is.

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