Wheel hub drive for a motor vehicle

Abstract

The invention relates to a wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (18), a wheel bearing (20) which has a first wheel bearing flange (22) rotationally fixed to the wheel carrier (18), a second wheel bearing flange (28) rotatably arranged about a wheel rotation axis (26) relative to the first wheel bearing flange (22), a first rolling element ring (32) and a second rolling element ring (34), an electric machine (40) which has a stator (42) rotationally fixed to the wheel carrier (18) and a rotor (44) by means of which the second wheel bearing flange (28) can be driven and is thereby rotatable relative to the first wheel bearing flange (22), and a vehicle wheel (12) rotationally fixed to the second wheel bearing flange (28), which has a rim (16) and a wheel disc (14), wherein the rolling element rings (32, 34) are coaxial are arranged axially overlapping with the wheel rotation axis (26) and axially spaced apart from each other.A shaft grounding device (46) is arranged axially between the first rolling element ring (32) and the second rolling element ring (34).

Description

[0001] The invention relates to a wheel hub drive for a motor vehicle according to the preamble of patent claim 1.

[0002] Such a wheel hub drive for a motor vehicle is already known, for example, from DE 10 2024 001 297 A1. The wheel hub drive has a wheel carrier and a wheel bearing, which has a first wheel bearing flange connected in a rotationally fixed manner to the wheel carrier, a second wheel bearing flange arranged so as to be rotatable about a wheel rotation axis relative to the first wheel bearing flange, a first rolling element ring, and a second rolling element ring. Also provided is an electric machine, which has a stator connected in a rotationally fixed manner to the wheel carrier and a rotor, by means of which the second wheel bearing flange can be driven and is thus rotatable relative to the first wheel bearing flange. Also provided is a vehicle wheel, which is connected in a rotationally fixed manner to the second wheel bearing flange and has a rim and a wheel disc. The rolling element rings are arranged coaxially to the wheel rotation axis, axially overlapping the wheel bearing flanges, and axially spaced from one another.

[0003] The object of the present invention is to improve a wheel hub drive of the type mentioned above.

[0004] This object is achieved by a wheel hub drive having the features of patent claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] In order to improve a wheel hub drive of the type specified in the preamble of patent claim 1, the invention provides that a shaft grounding device having a shaft grounding ring is arranged axially, i.e. in the axial direction of the wheel hub drive, between the first rolling element ring and the second rolling element ring. This enables particularly advantageous, space-saving and cost-effective integration of the shaft grounding ring into the wheel hub drive, so that electrical energy can be dissipated particularly advantageously. By arranging the shaft grounding device in the axial direction of the wheel hub drive between the rolling element rings, a space-saving function and integration is created, so that the shaft grounding device can be installed with only a few assembly steps and thus in a time- and cost-effective manner.In addition, a scope of delivery that includes the wheel bearing and the shaft grounding device can be created, allowing the wheel hub drive to be manufactured quickly and cost-effectively.

[0006] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the single figure, can be used not only in the respective specified combination, but also in other combinations or on their own, without departing from the scope of the invention.

[0007] The drawing shows in the only Fig. 1 shows a partial schematic longitudinal sectional view of a wheel hub drive for a motor vehicle.

[0008] The only Fig. 1 shows a partial schematic longitudinal sectional view of a wheel hub drive 10 for a motor vehicle, also referred to simply as a vehicle. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car. By means of the wheel hub drive 10, a vehicle wheel 12 of the motor vehicle can be driven, in particular purely electrically, as will be explained in more detail below. The vehicle wheel 12 is a component of the wheel hub drive 10 and has a wheel disc 14 and a rim 16, onto which, for example, a tire, in particular made of rubber, can be mounted. In the Fig.1, the wheel disc 14 and the rim 16 are formed integrally with one another, i.e., formed from a single piece and thereby connected to one another in a rotationally fixed manner, in particular permanently. The wheel hub drive 10 further comprises a wheel carrier 18 and a wheel bearing 20, which has a first wheel bearing flange 22 with a first bearing shell 24, which is connected to the wheel carrier 18 in a rotationally fixed manner, in particular permanently. The wheel bearing 20 further comprises a second wheel bearing flange 28 with a second wheel bearing shell 30, which is arranged about a wheel rotation axis 26 and is rotatable relative to the first wheel bearing flange 22 and thus to the first wheel bearing shell 24. This means that the wheel bearing flange 28 and thus the wheel bearing shell 30 and the wheel rotation axis 26 are rotatable relative to the wheel bearing flange 22 and thus relative to the wheel bearing shell 24 and also relative to the wheel carrier 18.The wheel bearing flange 28 and thus the wheel bearing shell 30 are, in particular permanently, connected in a rotationally fixed manner to the vehicle wheel 12, in particular via the wheel disc 14. The wheel bearing flanges 22 and 28 and thus the wheel bearing shells 24 and 30 are arranged coaxially to one another and thus coaxially to the wheel rotation axis 26.

[0009] The wheel bearing 20 is a rolling bearing comprising a first rolling element ring 32 and a second rolling element ring 34. The respective rolling element ring 32, 34 is formed by respective rolling elements 36, 38, which are arranged successively in the circumferential direction of the wheel bearing 20 extending around the wheel rotation axis 26. The rolling element rings 32 and 34 are arranged successively and spaced apart from one another axially, i.e., in the axial direction of the wheel hub drive 10 and thus along the wheel rotation axis 26. The wheel bearing shell 24 forms first raceways for the rolling elements 36 and 38, and the wheel bearing shell 30 forms second raceways for the rolling elements 36 and 38. If the vehicle wheel 12 and thus the wheel bearing flange 28 and the wheel bearing shell 30 rotate about the wheel rotation axis 26 relative to the wheel carrier 18 and relative to the wheel bearing flange 22 and thus relative to the wheel bearing shell 24, the rolling elements 36 and 38 roll, in particular directly, on the raceways.In particular, the wheel bearing shell 30 is mounted on the wheel bearing shell 24 via the rolling elements 36 and 38 so as to be rotatable about the wheel rotation axis 26 relative to the wheel bearing shell 24, in particular by means of roller bearings.

[0010] The wheel hub drive 10 also has an electric machine 40, which in this case is designed as an axial flux machine. The electric machine 40 has a rotor 42, which is connected, in particular permanently, in a rotationally fixed manner to the wheel carrier 18. Furthermore, the electric machine 40 has a rotor 44, which can be driven by the stator 42 and is thus rotatable about the wheel rotation axis 26 relative to the stator 42 and relative to the wheel carrier 18. The rotor 44 is connected, in particular permanently, in a rotationally fixed manner to the wheel bearing flange 28 and thus to the wheel bearing shell 30 and the vehicle wheel 12, so that by driving the rotor 44, the vehicle wheel 12 and the wheel bearing shell 30 or the wheel bearing flange 28 can be driven and thus can be rotated about the wheel rotation axis 26 relative to the stator 42 and the relative wheel carrier 18.In other words, the second wheel bearing flange 38 and thus the vehicle wheel 12 can be driven by means of the rotor 44 and can thus be rotated relative to the first wheel bearing flange 22 about the wheel rotation axis 26. The vehicle wheel 12 is formed separately from the wheel bearing flange 28 and is, in particular permanently, connected to the wheel bearing flange 28 in a rotationally fixed manner.

[0011] The rolling element rings 32 and 34 are arranged coaxially with the wheel rotation axis 26. Furthermore, the rolling element rings 32 and 34 are arranged axially overlapping the wheel bearing flanges 22 and 28, in this case the wheel bearing shells 24 and 30. Furthermore, the rolling element rings 32 and 34 are arranged axially spaced from one another, i.e., in the axial direction of the wheel hub drive 10.

[0012] In order to be able to realize advantageous shaft grounding in a particularly space-saving manner, it is provided that a shaft grounding device 46 is arranged axially between the rolling element rings 32 and 34, which has at least or exactly one shaft grounding ring 48. In this case, the shaft grounding device 46 is arranged axially overlapping the rotor 44 and / or the stator 42.

[0013] In particular, the rolling elements 36, 38 of the respective rolling element ring 32, 34, which are designed as balls in the present case, are arranged in the circumferential direction of the wheel hub drive 10 and thus around the wheel rotation axis 26 on or along an imaginary ring, which in turn is arranged coaxially to the wheel rotation axis 26. For example, the respective ring runs through a respective center point of the respective rolling element 36, 38 of the respective rolling element ring 32, 34. The wheel bearing 20 designed as a rolling element has, for example, the wheel bearing shell 24, in particular as the outer bearing shell, and the wheel bearing shell 30, in particular as the inner bearing shell, wherein the respective bearing shell is in particular a respective bearing ring. The wheel bearing flanges 22 and 28 are rotatably mounted relative to one another by means of the rolling element rings 32 and 34. By means of the first wheel bearing flange 22, the wheel bearing 20 can be or is fastened to the wheel carrier 18.The vehicle wheel 12 is or can be fastened to the wheel bearing 20 by means of the second wheel bearing flange 28. In particular, the second wheel bearing flange 28 comprises a wheel hub.

[0014] In the context of the present disclosure, a rotationally fixed connection between two, in particular, rotatably mounted elements is understood to mean that these two elements are arranged coaxially to one another and are connected to one another in such a way that they rotate, in particular always, at the same angular velocity. A rotatably mounted element is connected in a rotationally fixed manner to a housing or the wheel carrier 18, at least cannot be rotated relative to the housing or the wheel carrier 18. The feature that two elements, such as the respective rolling element ring 32, 34 and the respective wheel bearing flange 22, 28, are arranged axially overlapping one another is understood to mean that these elements are arranged in the region of the same axial coordinates; it was referred to a common reference axis, such as the wheel rotation axis 26. List of reference symbols 10 Wheel hub drive 12 vehicle wheel 14 Wheel disc 16 rim 18 wheel carriers 20 wheel bearings 22 first wheel bearing flange 24 First wheel bearing shell 26 Wheel rotation axis 28 Second wheel bearing flange 30 Second wheel bearing shell 32 rolling element ring 34 Rolling element ring 36 rolling elements 38 rolling elements 40 Electric Machine 42 Stator 44 Rotor 46 Shaft earthing device 48 Shaft earthing ring QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] DE 10 2024 001 297 A1

[0002]

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (18), a wheel bearing (20) having a first wheel bearing flange (22) connected in a rotationally fixed manner to the wheel carrier (18), a second wheel bearing flange (28) arranged so as to be rotatable about a wheel rotation axis (26) relative to the first wheel bearing flange (22), a first rolling element ring (32) and a second rolling element ring (34), an electric machine (40) having a stator (42) connected in a rotationally fixed manner to the wheel carrier (18) and a rotor (44) by means of which the second wheel bearing flange (28) can be driven and is thereby rotatable relative to the first wheel bearing flange (22), a vehicle wheel (12) connected in a rotationally fixed manner to the second wheel bearing flange (28), which vehicle wheel has a rim (16) and a wheel disc (14), wherein the rolling element rings (32, 34) are arranged coaxially to the wheel rotation axis (26) and axially spaced from each other, characterized bythat a shaft earthing device (46) having a shaft earthing ring (48) is arranged axially between the first rolling element ring (32) and the second rolling element ring (34). [2] Wheel hub drive (10) according to claim 1, characterized by that the shaft earthing device (46) is arranged axially overlapping the rotor (44) and / or the stator (42).

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