WO2012123174A2

WO2012123174A2 - Drive device for driving a wheel of a suspension-strut axle for an electrically drivable vehicle

Info

Publication number: WO2012123174A2
Application number: PCT/EP2012/051639
Authority: WO
Inventors: Martin Münster; Stephan Pollmeyer; Jens Heimann
Original assignee: Zf Friedrichshafen Ag
Priority date: 2011-03-16
Filing date: 2012-02-01
Publication date: 2012-09-20
Also published as: WO2012123174A3; DE102011005621A1

Abstract

A drive device (1) for driving a wheel (2) of a suspension-strut axle for an electrically drivable vehicle is proposed, comprising an electric machine (3) and a transmission (4, 5) which is connected on the output side of the electric machine (3) when viewed in the direction of force flux in the tractive mode, in which the housing (10) of the electric machine (12) or the housing (11) of the transmission (4, 5) is screwed directly to the wheel carrier (8) of the vehicle axle, is integrated as a multi-part welded component into the wheel carrier (8) or is embodied in one piece with the wheel carrier (8).

Description

A drive device for driving a wheel of a strut axle for an electrically driven vehicle

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, which are understood under Radnahen electric 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, the corresponding number of drives, so two or more exhibit. 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 DE 10 2007 039 059 A1 of the applicant, a driven vehicle axle designed as a torsion-beam axle is known, in which an electric motor is provided for each wheel of the axle, which is connected to the rotary axle. axis is arranged in the vehicle longitudinal direction, wherein the housing is a part of the longitudinal rocker of the torsion beam axle.

Radnahetriebe can be used on vehicles with four-wheel drive, front,

or rear-wheel drive, the axle types of the driven vehicle axles being conventional axle types, such Strut or double wishbone types 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 EP 1 961 602 A1 a drive device for driving the wheel which can be integrated into a vehicle wheel is known, 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 drive torques can be generated by radnahe electrical drives, 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, the transmission having 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. Under a high translation In this case, a ratio greater than 1:10, preferably 1:10 to 1:20, particularly preferably 1:14 to 1:18, in particular 1:16 understood.

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 total in conjunction 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 bolts for fixing the caliper of Disc brake at the same time represent housing screws for fastening the drive device to the wheel carrier (8).

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:

FIG. 1 shows a schematic view of the arrangement of a drive device designed according to the invention; and

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

Referring to FIG. 1, a drive device 1 for driving a wheel 2 of a suspension strut axis of an electrically drivable vehicle comprises an electric machine 3 and two planetary gearboxes 4, 5 connected in series in the power flow direction in traction on the output side of the electric machine 3. The first and the second planetary gearbox 4 , 5 are arranged in the example shown on the wheel 2 side facing the electric machine 3. In the figure, the shock absorber of the strut axis is provided with the reference numeral 6, wherein 7 denotes the wishbone and 8 the wheel carrier.

As can be seen from FIG. 1, the drive device 1 is arranged coaxially with the wheel axle 9. According to the invention, the housing 10 of the electrical See machine 3 or the housing 1 1 of the planetary gear 4, 5 connected directly to the wheel carrier 8 of the shock absorber axis, preferably screwed, integrated as a multi-part welding component in the wheel 8 or executed in one piece with the wheel carrier 8.

Here, the rotor of the preferably designed as an internal rotor electrical machine 3 is rotatably connected via a shaft 12 with the sun gear 13 of the first planetary gear 4, wherein the web 14 of the first planetary gear 4 rotatably connected via a further shaft 15 with the sun gear 16 of the second planetary gear 5 is. The output of the drive device

I via the web 17 of the second planetary gear 5 and a non-rotatably connected to the web 17 shaft 18 which is rotatably connected to the wheel hub of the wheel 2.

Furthermore, the ring gear 19 of the first planetary gear 4 and the ring gear 20 of the second planetary gear 5 are arranged fixed to the housing; they can be coupled to the housing 1 1 of the planetary gear 4, 5 of the drive device 1, designed in one piece with the housing 1 1 or be pressed into the housing 1 1. In the event that a ring gear is integral with the housing

I I is executed, a radial shoulder may be provided to compensate for a difference in diameter between the housing 1 1 and the ring gear.

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

As part of a development of the rotor of the electric machine 3 may be integral with the shaft 12, via which the rotor is connected to the sun gear 13 of the first planetary gear 4; Furthermore, the Shaft 15, via which the web 14 of the first planetary gear 4 is rotatably connected to the sun gear 16 of the second planetary gear 5, be integral with the web 14 of the first planetary gear 4.

The teeth 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 gear 16 of the second planetary gear 5 axially and radially supported by rolling bearings, plain bearings or thrust washers.

In this case, the helix angle of the sun gear 13 of the first planetary gear 4 is opposite to the helix angle of the sun gear 16 of the second planetary gear 5. In addition, the directions of the helix angles of the sun gear 13 of the first planetary gear 4 and the sun gear 16 of the second planetary gear 5 are to be selected in an advantageous manner so the loads on the bearings of the drive device 1, in particular on the bearings of the shaft 12, via which the rotor is connected to the sun gear 13 of the first planetary gear 4, are 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, via which the rotor is connected to the sun gear 13 of the first planetary gear 4 coincides according to an embodiment of the invention with the drive-side mounting of the rotor of the electric machine 3 together, so that the need for separate storage is eliminated, the Sun gear 13 of the first planetary gear 4 facing away from the bearing of the rotor of the electric machine 3 may be preferably axially biased by a spring element.

Furthermore, according to a development of the invention, at least one bearing side is connected to the web 17 of the second planetary gear 5 Shaft 18, ie the output of the drive device 1, formed by the wheel bearing of the wheel 2, 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 °. As a result, the number of bearings of the drive device 1 can be reduced in an advantageous manner.

The connection of the shaft 18 connected to the web 17 of the second planetary gear 5 with the wheel hub of the wheel 2 can take place by means of a plug-in splined connection or a polygonal profile; Alternatively, the end of the drive device 1 facing away from the rotatably connected to the web 17 of the second planetary gear 5 shaft 18, the wheel hub represent 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 18 for better centering of the shaft 18 is also possible.

In a further development of the invention, it is provided that the electric machine 3 and the planetary gear 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 like a Art cartridge in the prefabricated housing of the drive device is axially inserted.

FIG. 2 shows a further view of a part of a strut axle comprising a drive device 1 according to the invention. In FIG. 2, the rotor of the electric machine 3 is designated by the reference numeral 21 and the stator by the reference numeral 22. Furthermore, a transverse link 23, a stabilizer 24, the tie rod 25 and a disc brake 26 are shown. The housing 10 of the electric machine 3 is connected directly to the wheel carrier 8 of the strut axis in the example shown. As part of an embodiment 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 1 1 of the planetary gear 4, 5 or in the housing 10 of the electric machine 3 of the drive device 1 are integrated , Wherein the connecting screws for fixing the brake caliper can simultaneously represent housing screws for the attachment of the drive device 1 on the wheel 8.

As part of an embodiment of the invention, not shown, the electric machine 3 as a hollow shaft motor, i. be designed as an electric machine with a rotor designed as a hollow shaft 21, wherein the first and the second planetary gear 4, 5 are arranged on the side facing away from the wheel 7 of the electric machine 3 and the output shaft of the drive device 1, by the with the web 17th the second planetary gear 5 rotatably connected shaft 18 is formed, is guided through the cavity of the rotor 21 of the electric machine 3 to the wheel 1, 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 further storage (a first bearing is formed by the wheel bearing of the wheel 1, as already explained) provided with the web 17 of the second planetary gear 5 rotatably connected shaft 18, preferably on a pin of the shaft 18 is arranged. By interchanging the arrangement of the electric machine 3 and the first and second planetary gear 4, 5 in comparison to the embodiment of Figure 1 and Figure 2, the advantage is achieved that space is provided, which is used during compression, since the Housing 1 1 of the first and second planetary gear 4, 5 with smaller outer diameter is executable than the housing of the electric machine 3. Further, the connection between the electric machine 3 and the wheel hub vermiger be carried out stiff than in the embodiment according to Figures 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. REFERENCE CHARACTERS

driving device

wheel

electric machine

first planetary gear

second planetary gear

damper

wheel carrier

wheel axle

Housing of the electric machine 3 housing of the planetary gear 4, 5th

wave

Sun gear of the first planetary gear 4 Bridge of the first planetary gear 4 shaft

Sun gear of the second planetary gear 5 Bridge of the second planetary gear 5 shaft

Ring gear of the first planetary gear 4 Ring gear of the second planetary gear 5 Rotor of the electric machine 3

Stator of the electric machine 3

wishbone

stabilizer

tie rod

disc brake

Claims

claims

1 . Drive device (1) for driving a wheel (2) of a suspension strut axle for an electrically drivable vehicle, comprising an electric machine (3) and a transmission (4, 5) connected on the output side of the electric machine (3) in the direction of force flow in traction mode. characterized in that the housing (10) of the electric machine (12) or the housing (1 1) of the transmission (4, 5) screwed directly to the wheel carrier (8) of the vehicle axle, integrated as a multi-part welding component in the wheel carrier (8) or with the wheel carrier (8) are made in one piece.

2. Drive device (1) for driving a wheel (2) of a strut axle for an electrically driven vehicle, according to claim 1, characterized in that the connection of the caliper of the disc brake (26) and / or the damper (6) and / or the Spring in the housing (1 1) of the planetary gear (4, 5) or in the housing (10) of the electric machine (3) of the drive device (1) are integrated.

Third drive device (1) for driving 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 ,

4. Drive device (1) for driving a wheel (2) of a suspension strut axle for an electrically driven vehicle, according to at least one of the preceding claims, characterized in that the transmission (4, 5) two considered in the direction of force flow in traction on the output side of the electric machine ( 3) connected in series planetary gear (4, 5).

5. Drive device (1) for driving a wheel (2) of a strut axle for an electrically driven vehicle, according to claim 4, characterized characterized in that the rotor (21) of the electric machine (3) via a shaft (12) to the sun gear (13) of the first planetary gear (4) is rotatably connected, that the web (14) of the first planetary gear (4) via a Another shaft (15) rotatably connected to the sun gear (16) of the second planetary gear (5), 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) via the web (17) of the second planetary gear (5) and with the web (17) rotatably connected shaft (18) takes place, which is rotatably connected to the hub.

6. Drive device (1) for driving 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, via which the rotor (21) with the sun gear (13) of the first planetary gear (4) is connected.

7. Drive device (1) for driving 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), via which the web (14) of the first planetary gear (4) is rotatably connected to the sun gear (16) of the second planetary gear (5), with the web (14) of the first planetary gear (4) is made in one piece.

8. Drive device (1) for driving 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 web (17) of the second planetary gear (5) connected shaft (18) which forms the output of the drive device (1) is formed by the wheel bearing of the wheel (2).

9. Drive device (1) for driving 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 web (17) of the second planetary gear (5) connected Shaft (18) with the wheel hub by means of a plug-in splined connection or a polygonal profile or that the drive device (1) facing away from the end of the web (17) of the second planetary gear (5) connected to the shaft (18) represents the wheel hub itself.

10. Drive device (1) for driving 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) on the wheel (2) facing side of the electric machine (3) are arranged.

1 1. Drive device (1) for driving 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) on the wheel (2) The electric machine (3) is designed as a hollow shaft motor and the output shaft of the drive device (1) by the with the web (17) of the second planetary gear (5) rotatably connected shaft ( 18) is formed, through the cavity of the rotor (21) of the electric machine (3) to the wheel (2) is guided.

12. Drive device (1) for driving 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 5 000 revolutions / min, in particular between 6000 and 10,000 revolutions / min, more preferably around 7000 revolutions / min.

13. Drive device (1) for driving 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.