WO2009086884A1

WO2009086884A1 - Wheel assembly

Info

Publication number: WO2009086884A1
Application number: PCT/EP2008/010672
Authority: WO
Inventors: Benedikt Hoefner
Original assignee: Daimler Ag
Priority date: 2008-01-12
Filing date: 2008-12-16
Publication date: 2009-07-16
Also published as: DE102008004081A1

Abstract

The invention relates to a wheel assembly (10) for a motor vehicle having a wheel hub (12) rotatably supported about a wheel axis (A), whereon a rim (16) of a wheel can be fixed, wherein an electric machine (28) is disposed at least in areas in a part of a wheel space between the wheel hub (12) and the rim (16), wherein the electric machine (28) comprises a stator (30) fixed to a non-rotating vehicle part (38) and a rotor (32) that can be coupled to the rim (16) and the wheel hub (12) by means of a driving device, wherein a brake device (22) is disposed in another part of the wheel space between the wheel hub (12) and the rim (16), and wherein the driving device is disposed radially outside of the brake device (22).

Description

wheel assembly

The invention relates to a wheel assembly for a motor vehicle, having a wheel hub rotatably mounted about a wheel axle, to which a rim of a wheel can be fixed, wherein an electrical machine is at least partially disposed in a part of a wheel space between the wheel hub and the rim. In this case, the electric machine has a stator fixed to a non-rotatable vehicle part and a rotor which is coupled in terms of motion via a driver device with the rim and the wheel hub. In another part of the wheel space, a braking device is arranged between the wheel hub and the rim.

DE 199 48 224 C1 describes a wheel assembly for a motor vehicle, with a wheel hub rotatably mounted about a wheel hub, to which a rim of a wheel is fixed. In a wheel space between the wheel hub and the rim, an electric machine and a braking device are arranged. The electric machine comprises a hollow cylindrical stator, which is fixed to a rotationally fixed vehicle part. A trained as an external rotor rotor surrounds the stator on the outer peripheral side. A holder for holding the rotor is fixed together with the rim by means of wheel bolts on the wheel hub. The rotor concentrically encloses a mechanical braking device, which is arranged in a part of the wheel space between the wheel hub and the rim.

In the wheel assembly according to the prior art, maintenance work on the braking device is comparatively complicated, since the electric machine must be at least partially disassembled in order to allow unrestricted accessibility to the braking device. Object of the present invention is therefore to provide a wheel assembly of the type mentioned, in which accessibility to the braking device is improved.

This object is achieved by a wheel assembly with the features of claim 1. Advantageous embodiments with expedient developments of the invention are specified in the dependent claims.

The wheel assembly according to the invention for a motor vehicle has a wheel hub rotatably mounted about a wheel axle, on which a rim of a wheel can be fixed. Here, an electric machine is at least partially disposed in a part of a wheel space between the wheel hub and the rim, wherein the electric machine has a stator fixed to a non-rotatable vehicle part and a rotor coupled via a driving device with the rim and the wheel hub rotor. In another part of the wheel space, a brake device is arranged between the wheel hub and the rim, wherein the driver device is arranged radially outside the brake device.

As a result, the braking device can be made particularly easily accessible by the rim is released from the wheel hub. Neither when changing the rim nor during maintenance of the brake device or when changing the brake device, the electric machine must be dismantled.

In an advantageous embodiment of the invention it is provided that the entrainment means comprises at least one axially arranged of the rotor driving pin, which is to be brought into engagement with a corresponding recess of the rim. This allows a particularly easy-to-solving positive connection of the rotor to the rim, which facilitates a transfer of torques and forces between the rotor and rim.

Furthermore, in the axial arrangement of the driving pin or pins, an outer diameter of the rotor can be particularly large, wherein the rotor can be formed close enough to a rim base of the rim. As a result, the electric machine can generate a particularly high power. Furthermore, a particularly cost-effective entrainment device is provided by the driving pins, which are to be brought into the corresponding recesses in the rim in engagement. Also, the rim is particularly easy to set at the wheel hub. In a supplementary or alternative embodiment of the invention, the entrainment device may comprise at least one radially projecting beyond the rotor tooth, which is to be brought into engagement with a arranged on the rim corresponding tooth in engagement or with a corresponding recess in the rim. This allows a particularly secure form-locking connection of the rotor to the rim in the manner of a splined connection, by which forces and torques can be transferred particularly well between the rotor and rim.

Furthermore, components of the wheel assembly, such as the brake device, the wheel hub, the stub shaft and / or the wheel bearing, may be configured identically to a wheel assembly in which no electrical machine is arranged in the part of the wheel chamber between the wheel hub and the rim. A maintenance and / or replacement of wearing parts, such as a brake disc and / or a brake caliper of the brake device can be done without disassembling the electric machine.

In an advantageous embodiment of the invention, the arranged on the rim corresponding tooth is formed integrally with the rim. As a result, a particularly resilient connection of the corresponding tooth with the rim is created.

Furthermore, it has proven to be advantageous if an axial length of the tooth is at least substantially equal to an axial length of the rim base of the rim. By creating a comparatively large contact surface between the rotor-side tooth and the rim-side tooth, a particularly uniform distribution of forces and torques acting between the rotor and the rim is made possible in this case.

Furthermore, it is advantageous if at least one of mutually facing outer edges of the teeth opposite to the wheel axle is formed inclined towards a motor vehicle-external side of the wheel. As a result, a particularly simple attachment and dismantling of the rim is made possible, since with increasing pushing of the rim an increasingly stronger adhesion between the teeth brought into contact is formed.

It is furthermore advantageous if at least two components of the driver device are arranged uniformly spaced with respect to the rotor. Thus, the axially arranged of the rotor driving pin and / or the radially projecting beyond the rotor teeth can lead to a particularly uniform outer peripheral side distribution of transmitted between the rotor and the rim forces and torques. As a result, it can be ensured, in particular, that there is constant contact with the tooth protruding radially beyond the rotor with the corresponding tooth on the rim.

In an advantageous embodiment of the invention, the driver device on the rotor side and / or rim side on a damping element. Thus, the teeth radially projecting beyond the rotor and / or the corresponding teeth arranged on the rim can have a rubber coating which is suitable for compensating for shocks which are transmitted from a roadway to the wheel. Likewise, can be compensated by the damping elements torque fluctuations when driving the wheel by means of the electric machine and noise are attenuated. The same advantages has a gumming of the axially arranged of the rotor driving pin and / or the corresponding recesses in the rim.

Furthermore, it has proven to be advantageous if the driver device is formed on the rotor side in one piece with the rotor. As a result, on the one hand a particularly secure fixing of the driving pins and / or the radially projecting beyond the rotor teeth on the rotor is achieved. On the other hand, such an assembly effort of a subsequent attachment of the driver device is reduced to the rotor.

In a further advantageous embodiment of the invention, the electric machine is designed as an external rotor machine, wherein the stator and / or the rotor are formed as a hollow cylinder. As a result, on the one hand, a particularly large diameter of the rotor is created, which enables a particularly powerful driving of the wheel. Furthermore, sufficient space for arranging the braking device in the wheel assembly is created within the hollow cylindrical stator.

It is also advantageous if a, in particular integrally formed with the stator, connecting element for fixing the stator to the non-rotatable vehicle part comprises a perforated ring. This allows a particularly secure and accurate setting of the stator to the non-rotatable vehicle part. If the connection element is formed integrally with the stator, it is advantageously unnecessary to mount another component. Finally, it has proven to be advantageous if the electric machine is to be arranged as an assembly in the part of the wheel space. Thus, the electric machine can be pre-assembled before it is fixed to the non-rotating vehicle part. As a result, a particularly high accuracy of fit of the electric machine in the part of the wheel space can be achieved. Likewise, an air gap formed between the stator and the rotor can be set particularly accurately.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings, in which the same or functionally identical elements are provided with identical reference numerals.

Showing:

1 is a sectional view of a wheel assembly in the direction of a wheel axle, wherein in a part of a wheel space between a wheel hub and a rim, an electric machine is arranged, wherein in another part of the wheel chamber, a braking device is arranged, and wherein radially via a rotor of the electric Machine protruding teeth are brought into contact with corresponding, arranged on the rim teeth; and

Fig. 2 is a sectional view of a second embodiment of the

Wheel assembly according to FIG. 1, wherein instead of the teeth brought into contact with each other on the rotor axially driving pins are arranged, which are brought into engagement with corresponding recesses in the rim.

1 shows an upper half of a wheel assembly 10 which is cut centrally along a wheel axle A. The wheel assembly 10 comprises a wheel hub 12 mounted rotatably about the wheel axle A, to which a rim 16 of a wheel is fixed by means of fastening screws 14. The wheel hub 12 is mounted by means of two axially spaced wheel bearings 18 on a coaxial with the wheel axle A extending stub shaft 20. On the wheel hub 12, a brake device 22 is further defined by means of the fastening screws 14, which is designed here as a disc brake with a brake caliper 24 and a brake disc 26. In an outer part of a wheel space between the wheel hub 12 and the rim 16, an electric machine 28 is arranged. The electric machine 28 is designed as an external rotor machine and has a hollow cylindrical stator 30 and a relative to the stator 30 movable, outer rotor 32.

Between the stator 30 and the rotor 32, an air gap 34 is formed. The rotor 32 is mounted on the stator 30 via thin ring bearings 36 arranged axially outside the stator 30. By means of the thin-ring bearings 36, a sliding bearing of the rotor 32 is provided on the stator 30. The electric machine 28 is completely integrated into the outer part of the wheel space between the rim 16 and the wheel hub 12.

A connecting element for fixing the stator 30 to a non-rotatable vehicle part 38 in this case comprises a perforated ring 40. About the perforated ring 40, which is fixed by means of fastening screws 14 to the rotationally fixed vehicle part 38, it is possible, the electric machine 28 as a pre-assembled assembly, which the stator 30 and the rotor 32 includes to arrange in the outer part of the wheel space.

The perforated ring 40 thus represents a defined interface, by means of which a particularly precise connection of the electrical machine 28 with the rotationally fixed vehicle part 38 is made possible. The connecting element which surrounds the perforated ring 40 for fixing the stator 30 to the rotationally fixed vehicle part 38 may also be formed integrally with the stator 30. In particular, the connection element may be part of a housing of the stator 30.

According to the exemplary embodiment of the wheel assembly 10 shown in FIG. 1, a driving device for coupling movements of the rim 16 and the rotor 32 comprises a plurality of teeth 42 projecting radially beyond the rotor 32. The outer peripheral side arranged on a housing of the rotor 32, in FIG. 1 shown tooth 42 is formed integrally with the housing of the rotor 32. Alternatively, it can be provided to attach the teeth 42 subsequently to the housing of the rotor 32. According to FIG. 1, the teeth 42 are brought into abutment with corresponding teeth 44 arranged on the rim 16. Of course, it can be provided in an alternative embodiment of the wheel assembly 10, that for the positive connection of the rotor 32 with the rim 16 of the rotor-side tooth 42 is brought into engagement with a corresponding not shown in the present figure in the rim 16. By arranging at least two teeth 42 on the rotor 32 equally spaced on the outside circumference, which are brought into contact with two rim-side, corresponding teeth 44, it can be ensured that a lasting fit of the tooth 42 and the corresponding tooth 44 is achieved. Furthermore, forces and torques can be transmitted in a particularly evenly distributed manner between the rotor 32 and the rim 16.

By arranging the teeth 42, 44 comprehensive entrainment radially outward of the brake device 22 accessibility to the brake device 22 is ensured, which allows a particularly easy maintenance of the caliper 24 and / or the brake disc 26. Of course, the braking device 22 embodied as a disk brake in alternative embodiments of the wheel assembly 10 can also be designed as a drum brake or other mechanical braking device 22.

The teeth 42, 44 have an axial length substantially equal to an axial length of a rim base 46 of the rim 16. As a result, a particularly large contact surface of the teeth 42, 44 given to each other. Of course, it is alternatively conceivable to dimension the axial length of the teeth 42, 44 such that the axial length of the rotor 32 is at least substantially equal.

In Fig. 1 is further recognizable that facing outer edges of the teeth 42, 44 are formed with respect to the wheel axis A to a motor vehicle remote outside of the wheel out inclined. By the tapered forming of the teeth 42, 44 mounting the rim 16 is particularly easy to carry out. The rim 16 is in this case connected to the rotor 32 to form a positive connection by means of the teeth 42, 44 comprehensive entrainment device.

Subsequently, the rim 16 is frictionally fixed by means of the fastening screws 14 to the wheel hub 12. This creates a positive and non-positive unit, which a Particularly good transmission of forces and torques between the electric machine 28 and the rim 16 allows. Furthermore, so when disassembling the rim 16, the electric machine 28 must not be removed and the rotor 32 and the stator 30 need not be separated from each other.

From Fig. 1 it can be seen that the teeth 42, 44 have at the mutually facing outer edges damping elements 48 in the form of an elastic rubber coating. In this way, shocks which are transmitted from a roadway to the wheel can be damped so that impact loads of the electric machine 28 are minimized. Likewise, the damping elements 48 serve to compensate for torque fluctuations in driving the rim 16 by means of the rotor 32 and cause noise to be attenuated.

For integrating the electric machine 28 in the outer part of the wheel space between the rim 16 and the wheel hub 12 is on standard components of the wheel assembly 10, only the rotationally fixed vehicle part 38, which is presently designed as a wheel carrier, adapt for tying the ring gear 40. Other components of the wheel assembly 10 such as the brake device 22, the wheel hub 12, the wheel bearing 18, the stub shaft 20, and components of a chassis, of which in Fig. 1, a suspension arm 50 is shown, standard components can be identical. The same applies to components of the chassis not shown here, such as springs, dampers, subframe and the like.

FIG. 2 shows an alternative embodiment of the wheel assembly 10, in which the driving device arranged radially outside the braking device 22 comprises driving pins 52. The driving pin 52 shown in Fig. 2 is disposed axially of the rotor 32 on the housing of the rotor 32 and is brought into engagement with a corresponding recess 54 in the rim 16.

For a particularly effective and uniform transmission of torques and forces between the rotor 32 and the rim 16, a plurality of driving pins 52 are arranged uniformly spaced from one another on the housing of the rotor 32. The driving pins 52 may be subsequently attached to the rotor 32 or be formed integrally with this already during the manufacture of the rotor 32. The driving pin 52 and the recess 54 presently have a rubber coating for damping shocks, for compensating for torque fluctuations of the electric machine 28 and for damping noise. Due to the axial arrangement of the driving pins 52 on the rotor 32, a diameter of the rotor 32 can be dimensioned such that the rotor 32 reaches on the outer peripheral side particularly close to the rim 46 of the rim 16. As a result, a particularly high power can be generated by means of the electric machine 28. Other elements of the alternative embodiment of the wheel assembly 10 shown in FIG. 2 correspond to the elements shown in FIG.

By a four-fold storage, namely the two wheel bearings 18 and the two thin-ring bearings 36, there is the danger of overdetermination. This danger can be circumvented in that the driving pin 52 is designed such that it has axial and radial play to the rim 16 and can only transmit forces in the circumferential direction. Another advantage results from the fact that coming from the road forces are absorbed directly by the wheel bearings 18 and thus do not burden the electric machine 28.

Main loads between the wheel and the track are received by the wheel hub 12 and the rim 16 in the wheel assemblies 10 shown in FIGS. 1 and 2. The transmission of torques and forces between the rotor 32 and the rim 16 is ensured by the detachable, positive connections between the rotor 32 and the rim 16, without having to wait for the braking device 22 to remove the electric machine 28.

Claims

claims

A wheel assembly for a motor vehicle, comprising a wheel hub (12) rotatably mounted about a wheel axle (A) and to which a rim (16) of a wheel can be secured, wherein an electric machine (28) is disposed at least partially in a part of a wheel space between the wheel Wheel hub (12) and the rim (16) is arranged, wherein the electric machine (28) fixed to a non-rotatable vehicle part (38) stator (30) and via a driver device with the rim (16) and the wheel hub (12) motion-coupled rotor (32), and wherein in a different part of the wheel space between the wheel hub (12) and the rim (16) a braking device (22) is arranged, characterized in that the entrainment device is arranged radially outside of the braking device (22) ,

2. Wheel assembly according to claim 1, characterized in that the entrainment means comprises at least one axially of the rotor (32) arranged driving pin (52) which is to be brought into engagement with a corresponding recess (54) in the rim (16).

3. Wheel assembly according to claim 1 or 2, characterized in that the entrainment means comprises at least one radially beyond the rotor (32) projecting tooth (42), which with one on the rim (16) arranged corresponding tooth (44) in abutment or with a corresponding recess in the rim (16) is to be engaged.

4. Wheel assembly according to claim 3, characterized in that on the rim (16) arranged corresponding tooth (44) is formed integrally with the rim (16).

5. Wheel assembly according to claim 3 or 4, characterized in that an axial length of the tooth (42, 44) an axial length of a rim base (46) of the rim (16) is at least substantially equal.

6. Wheel assembly according to one of claims 3 to 5, characterized in that at least one of mutually facing outer edges of the teeth (42, 44) relative to the wheel axle (A) is inclined to a motor vehicle remote outside of the wheel.

7. Wheel assembly according to one of claims 1 to 6, characterized in that at least two components of the driving device with respect to the rotor (32) are arranged uniformly spaced.

8. Wheel assembly according to one of claims 1 to 7, characterized in that the entrainment means on the rotor side and / or rim side a damping element (48).

9. Wheel assembly according to one of claims 1 to 8, characterized in that the driving device is formed on the rotor side in one piece with the rotor (32).

10. Wheel assembly according to one of claims 1 to 9, characterized in that the electrical machine (28) is designed as an external rotor machine, wherein the stator (30) and / or the rotor (32) are formed as a hollow cylinder.

11. Wheel assembly according to one of claims 1 to 10, characterized in that one, in particular integrally with the stator (30) formed, connecting element for fixing the stator (30) on the non-rotatable vehicle part (38) comprises a perforated ring (40).

12. Wheel assembly according to one of claims 1 to 11, characterized in that the electrical machine (28) is to be arranged as an assembly in the part of the wheel space.