Wheel hub drive for a motor vehicle and motor vehicle

Abstract

The invention relates to a wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (12), a wheel bearing (14) having a first bearing shell (16) connected in a rotationally fixed manner to the wheel carrier (12) and a second bearing shell (20) arranged coaxially and rotatably relative to the first bearing shell (16), an electric machine (24) having a stator (26) connected in a rotationally fixed manner to the wheel carrier (12) and a rotor (30) by means of which the second bearing shell (20) can be driven and is thereby rotatable relative to the first bearing shell (16), a vehicle wheel (40) having a rim (42) and a wheel disc (46) extending outwardly in the radial direction (48) of the vehicle wheel (40) from the wheel bearing (14) at least to a radially outer edge (R) of the stator (26) and is connected to the second bearing shell (20) in a screw-free and permanently rotationally fixed manner, characterized in thatthat the second bearing shell (20) is arranged radially inside the first bearing shell (16).,

Description

[0001] The invention relates to a wheel hub drive for a motor vehicle, in particular for a motor vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle with at least one such wheel hub drive.

[0002] WO 2022 / 096504 A1 discloses a wheel system for a vehicle, comprising a stator, a rotor and a pivot bearing.

[0003] The object of the present invention is to provide a wheel hub drive for a motor vehicle, in particular for a motor vehicle, and a motor vehicle with at least one such wheel hub drive, so that a particularly lightweight design and a particularly simple assembly of the wheel hub drive can be realized.

[0004] This object is achieved by a wheel hub drive having the features of patent claim 1 and by a motor vehicle having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect of the invention relates to a wheel hub drive, also referred to as a wheel hub drive device or wheel hub drive unit, for a motor vehicle, also simply referred to as a vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car. This means that the motor vehicle, in its fully manufactured state, has the wheel hub drive and can be driven by means of the wheel hub drive, in particular purely electrically. Thus, the wheel hub drive is preferably an electric wheel hub drive, by means of which the motor vehicle can be driven, in particular purely electrically. For example, in its fully manufactured state, the motor vehicle has at least or exactly two vehicle axles, which are arranged one behind the other and thus consecutively in the longitudinal direction of the motor vehicle and are simply also referred to as axles.The respective vehicle axle has at least or exactly two respective vehicle wheels, also simply referred to as wheels, wherein the respective vehicle wheels of the respective vehicle axle are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle. The vehicle wheels are ground contact elements by means of which the motor vehicle can be or is supported downwards on a ground in the vertical direction of the motor vehicle. If the motor vehicle is driven along the ground while the motor vehicle is supported downwards on the ground in the vertical direction of the motor vehicle via the ground contact elements, the ground contact elements roll, in particular directly, on the ground. As will be explained in more detail below, a first of the vehicle wheels is, in particular precisely, a component of the wheel hub drive.When reference is made above and below to the vehicle wheel, this refers, unless otherwise stated, to the first vehicle wheel of the wheel hub drive. The vehicle wheel can be driven, in particular purely electrically, by means of the wheel hub drive. The aforementioned wheel hub drive is also referred to as the first wheel hub drive, whereby when reference is made above and below to the wheel hub drive, this refers, unless otherwise stated, to the first wheel hub drive. For example, the motor vehicle can have at least one second wheel hub drive provided in addition to the wheel hub drive, which can, for example, in particular precisely, comprise a second of the vehicle wheels, whereby the second vehicle wheel can be driven, in particular purely electrically, by means of the second wheel hub drive. It is preferably provided that the first vehicle wheel and the second vehicle wheel are the vehicle wheels on the same vehicle axle.The previous and following statements regarding the first wheel hub drive can easily be transferred to the second wheel hub drive and vice versa.

[0006] The wheel hub drive (first wheel hub drive) has a wheel carrier and a wheel bearing, which has a first bearing shell that is connected to the wheel carrier, in particular permanently and in a rotationally fixed manner, and a second bearing shell that is arranged coaxially and rotatably to the first bearing shell. This means that the second bearing shell is rotatable about a wheel rotation axis relative to the first bearing shell and relative to the wheel carrier, wherein the second bearing shell is arranged coaxially to the first bearing shell with respect to the wheel rotation axis. The wheel bearing is preferably a rolling bearing. It is conceivable for the first bearing shell and the wheel carrier to be formed separately from one another and, in particular permanently, connected to one another in a rotationally fixed manner. Furthermore, it would be conceivable for the first bearing shell and the wheel carrier to be formed integrally with one another and thus, in particular permanently, connected to one another in a rotationally fixed manner.The feature that two components, such as the first bearing shell and the wheel carrier, are formed integrally with one another means that the integrally formed components are formed from a single piece, so that the components are formed integrally or in one piece with one another. This means that the components are not formed separately from one another and connected to one another, but rather the components are formed from a single piece, i.e., by a body formed from a single piece and thus formed integrally, i.e., integrally manufactured, which is a monoblock.

[0007] For example, the wheel bearing has rolling elements. For example, the first bearing shell forms at least one first raceway for the first rolling elements, and the second bearing shell forms, for example, at least one second raceway for the first rolling elements. In particular, when the second bearing shell rotates about the wheel's axis of rotation relative to the first bearing shell, the rolling elements roll on the first raceway and on the second raceway, in particular directly, so that, for example, the rolling elements directly contact the first raceway and the second raceway.

[0008] The wheel hub drive also has an electric machine, which has a stator, in particular a permanently and non-rotatably connected stator, and a rotor. The rotor can be driven by the stator and is thus rotatable about a machine axis of rotation relative to the stator. The rotor is preferably arranged coaxially with the bearing shells, so that the machine axis of rotation preferably coincides with the wheel axis of rotation. By driving the rotor, the bearing shell can be driven by the second rotor and is thus rotatable about the wheel axis of rotation relative to the first bearing shell. The wheel hub drive also has the vehicle wheel (first vehicle wheel). The vehicle wheel has a rim and a wheel disc. For example, a tire, which is made in particular of rubber and is formed separately from the wheel disc and separately from the rim and can be a component of the vehicle wheel, is mounted on the rim and thus fastened to the rim.In particular, when the vehicle wheel rolls, in particular directly, on the aforementioned ground, the tire rolls, in particular directly, on the ground. The wheel disc extends radially, i.e. in the radial direction of the vehicle wheel and thus of the wheel hub drive, outwards, starting from the wheel bearing, at least as far as a radially outer edge of the stator, i.e. in the radial direction of the vehicle wheel, the axial direction of which runs perpendicular to the radial direction of the vehicle wheel. Preferably, the radially outer edge of the stator is the radially outermost edge of the stator, thus the outermost edge of the stator viewed outwards in the radial direction of the vehicle wheel and thus of the wheel hub drive, which stator ends, for example, at its radially outer, in particular radially outermost, edge viewed outwards in the radial direction of the vehicle wheel.The radial direction of the vehicle wheel coincides with the radial direction of the wheel hub drive as a whole, whose axial direction coincides with the axial direction of the vehicle wheel. The axial direction of the vehicle wheel and thus of the wheel hub drive coincides with the wheel's axis of rotation. The term "radial" refers to the radial direction of the vehicle wheel and thus of the wheel hub drive, and the term "axial" refers to the axial direction of the vehicle wheel and thus of the wheel hub drive. In other words, the term "radial" refers to the radial direction of the vehicle wheel and thus of the wheel hub drive, while the term "axial" refers to the axial direction of the vehicle wheel and thus of the wheel hub drive. When reference is made above and below to the radial direction, this means the radial direction of the vehicle wheel and thus of the wheel hub drive, unless otherwise stated.When reference is made to the axial direction above and below, this means, unless otherwise stated, the axial direction of the vehicle wheel and thus of the wheel hub drive.

[0009] The wheel disc is screw-free, i.e., without screws and permanently connected to the second bearing shell in a rotationally fixed manner. In other words, the second bearing shell is permanently connected to the wheel disc in a rotationally fixed manner without the use of screws, i.e., without the second bearing shell being connected to the wheel disc in a rotationally fixed manner by means of screws. In the context of the present disclosure, the feature that two components, such as the wheel disc and the second bearing shell, are connected to one another in a screw-free manner is to be understood as meaning that these components are connected to one another without screws, i.e., without the use of screws. Screws are to be understood as meaning both screws which have a screw shaft with an external thread and nuts which have an opening with an internal thread.Thus, the wheel disc and the second bearing shell are free of screw elements, that is, they are not permanently rotationally fixed to each other by screw elements.

[0010] Preferably, the wheel disc and the rim are rotationally fixed to each other. By driving the second bearing shell, that is, by rotating the second bearing shell about the wheel axis and relative to the first bearing shell, the wheel disc and, for example, via the wheel disc the rim and thus, for example, the tire can be driven, whereby the vehicle, in particular the motor vehicle, in particular purely electrically, can be driven by means of the rotor.

[0011] In order to achieve a particularly lightweight design for the wheel hub drive and particularly simple assembly of the wheel hub drive, the invention provides for the second bearing shell to be arranged radially within the first bearing shell. Furthermore, this allows for considerable design freedom with regard to the design of the rim and / or wheel disc, as well as with regard to the cupping of the wheel disc and / or rim. The screw-free connection between the wheel disc and the second bearing shell of the wheel bearing eliminates the need for conventionally provided wheel bearing screw connections, thereby keeping the number of parts, weight, costs, and installation space requirements of the wheel hub drive to a particularly low level.

[0012] In principle, it would be conceivable for the rim and the wheel disc to be formed integrally with one another and thus made from a single piece and thus connected to one another in a rotationally fixed manner.

[0013] However, it has proven particularly advantageous if the rim and the wheel disc are formed separately from one another and are connected to one another in a rotationally fixed manner, particularly in a manner that allows for non-destructive detachment. This allows, for example, a tire change (also known as a wheel change) to be carried out advantageously. During such a tire change, the rim and, with it, the tire mounted on the rim are removed from the wheel disc, while the wheel disc remains connected to the second bearing shell in a screw-like manner and rotationally fixed.

[0014] In order to achieve a particularly space-saving design and particularly simple assembly of the wheel hub drive, one embodiment of the invention provides for the wheel hub drive to have a fastening ring that is connected, in particular permanently, to the wheel disc in a rotationally fixed manner. In principle, it would be conceivable for the fastening ring and the wheel disc to be integrally formed with one another, thus being made from a single piece. Furthermore, it would be conceivable for the fastening ring and the wheel disc to be formed separately from one another and connected to one another in a rotationally fixed manner, in particular permanently, without screws.

[0015] The fastening ring is arranged radially outside the rotor and radially outside the stator. The fastening ring also has openings, which can be designed as bores, for example. For example, the openings are designed as through-openings that completely penetrate a fastening ring in the axial direction of the vehicle wheel and the wheel hub drive. Screws are accommodated in the openings, in particular such that exactly one of the screws is accommodated in each opening. The rim is fastened to the wheel disc by means of the screws, in particular in a non-destructively detachable and / or rotationally fixed manner. This makes changing a tire particularly easy.

[0016] The rim and the wheel disc, for example, form a wheel unit or are part of such a wheel unit. The wheel unit is connected to the second bearing shell via the wheel disc in a rotationally fixed manner, so that by rotating the second bearing shell, the wheel unit can be driven and thus rotated about the wheel rotation axis relative to the wheel carrier.

[0017] Preferably, the electric machine is a high-voltage component whose electrical voltage, in particular the electrical operating or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and most preferably several hundred volts. Preferably, the stator is connected, in particular permanently, to the wheel carrier in a rotationally fixed manner.

[0018] A further embodiment is characterized in that the wheel hub drive has a braking device which has a friction plane and a friction region in which the friction elements of the braking device can be brought into, in particular direct, frictional interaction in order to thereby brake the second bearing shell and thus the vehicle wheel, in particular with regard to rotations occurring about the axis of rotation and relative to the wheel carrier. A first of the friction elements is, for example, in particular permanently, connected in a rotationally fixed manner to the wheel carrier. A second of the friction elements is, for example, in particular permanently, connected in a rotationally fixed manner to the second bearing shell. For example, the second friction element is, in particular permanently, connected in a rotationally fixed manner to the wheel disc and via the latter, in particular permanently, connected in a rotationally fixed manner to the second bearing shell.By means of the braking device, the second bearing shell and thus the wheel unit can be braked with respect to their rotation about the axis of rotation and relative to the first bearing shell and thus relative to the wheel carrier, whereby the motor vehicle or the vehicle wheel can be braked. The feature that the friction elements can be brought into frictional interaction is to be understood that the friction elements can be brought into frictional interaction in order to thereby brake the second bearing shell relative to the first bearing shell and thus relative to the wheel carrier, in particular with respect to the aforementioned rotation of the second bearing shell and thus of the wheel disc about the wheel rotation axis and relative to the first bearing shell and relative to the wheel carrier.In other words, by actuating the braking device, in particular hydraulically, the friction elements can be brought into such a, in particular direct, interaction that the friction elements rub against each other, in particular directly, whereby the second bearing shell and thus the wheel disc can be braked with respect to their respective rotation about the wheel rotation axis and relative to the first bearing shell and relative to the wheel carrier. This allows the wheel unit and thus the motor vehicle to be braked.

[0019] In principle, it would be conceivable for the braking device to be designed as a drum brake. However, it has proven particularly advantageous for the braking device to be a disc brake. In this case, for example, the first friction element is a brake caliper and the second friction element is a brake disc. Preferably, the first friction element is separate from the wheel carrier and, in particular, permanently connected to the wheel carrier in a rotationally fixed manner.

[0020] To achieve particularly simple assembly of the wheel hub drive, it has proven particularly advantageous if the wheel bearing comprises a first sub-bearing and a second sub-bearing. The first sub-bearing is arranged axially overlapping the riding area of ​​the braking device, and the second sub-bearing is arranged axially overlapping the stator.

[0021] In the context of the present disclosure, the feature that two components, such as the second bearing plate and the wheel disc, are connected to one another in a rotationally fixed manner, is to be understood as meaning that the components connected to one another in a rotationally fixed manner are arranged coaxially to one another and, in particular when the components are driven, rotate together or simultaneously about a component rotation axis common to the components, such as the wheel rotation axis, at the same angular velocity, in particular relative to a reference element, such as a wheel carrier. In other words, two elements are connected to one another in a rotationally fixed manner if they are arranged coaxially to one another, in particular with respect to their component rotation axis or with respect to a rotational symmetry axis, and if they are connected to one another in such a way that they always rotate with the same angular velocity.An element is connected to a housing in a rotationally fixed manner if it can be rotated relative to the housing. Thus, for example, an element is connected to the wheel carrier in a rotationally fixed manner if it cannot be rotated relative to the wheel carrier.

[0022] The feature that two components are connected or coupled to one another in a torque-transmitting manner means that the components are coupled or connected to one another in such a way that torque can be transmitted between the components. If the components are connected or coupled to one another in a rotationally fixed manner, the components are also connected or coupled to one another in a torque-transmitting manner. Two components connected to one another in a torque-transmitting manner can thus be connected to one another in a rotationally fixed manner. Furthermore, it is conceivable that two components connected to one another in a torque-transmitting manner are connected to one another in a torque-transmitting manner via an intermediate transmission unit, so that torque can be transmitted between the components via the transmission unit, while the components are connected to one another in a torque-transmitting manner, although the components can be rotatable relative to one another.

[0023] The feature that two components, such as the second bearing shell and the wheel disc, are permanently connected or coupled to one another in a torque-transmitting manner means that a switching element is not provided that can be switched between a coupling state that connects or couples the components to one another in a torque-transmitting manner and a decoupling state in which no torque can be transmitted between the components via the switching element. Rather, the components are always and therefore permanently torque-transmitting, i.e., connected or coupled to one another in such a way that torque can be transmitted between the components. Thus, for example, one of the components can be driven by the other component, or vice versa.

[0024] In particular, the feature that two components such as the second bearing shell and the wheel disc are permanently connected or coupled to one another in a rotationally fixed manner is to be understood as meaning that a switching element is not provided which can be switched between a coupling state which connects or couples the components to one another in a rotationally fixed manner and a decoupling state in which the components are decoupled from one another and can be rotated relative to one another, so that no torque can be transmitted between the components via the switching element, but rather the components are always connected or coupled to one another, thus permanently connected or coupled to one another in a rotationally fixed manner.

[0025] Furthermore, the feature that two components can be connected or coupled to one another in a rotationally fixed manner means that the components are assigned a switching element which can be switched between the at least one coupling state and the at least one decoupling state. In the coupling state, the components are connected or coupled to one another in a rotationally fixed manner by means of the switching element. In the decoupling state, the components are decoupled from one another, so that in the decoupling state the components can be rotated relative to one another about the component rotation axis. The same applies to the feature that two components can be connected or coupled to one another in a torque-transmitting manner.Thus, for example, the feature that two components can be connected or coupled to one another in a torque-transmitting manner is to be understood as meaning that a switching element is assigned to the components, wherein the switching element can be switched between at least one connected state and at least one released state. In the connected state, the components are coupled or connected to one another in a torque-transmitting manner by means of the switching element, so that torques can be transmitted between the components, in particular via the switching element. In the released state, the components are decoupled from one another, so that in the released state, no torque can be transmitted between the components via the switching element.

[0026] The feature “radially overlapping” is to be understood as follows: Two elements, in particular those which are essentially rotationally symmetrical, are arranged radially, in particular with respect to one another, in particular with respect to a common axis running, for example, in the radial direction of the wheel hub drive and / or in the radial direction of the wheel hub drive, if they are each arranged at least partially in a region of the same radial coordinates, in particular the same angular coordinates. The feature “axially overlapping” is to be understood as follows: Two elements are arranged axially overlapping, in particular with respect to one another, with respect to a common axis running, in particular in the axial direction of the wheel hub drive and / or in the axial direction of the wheel hub drive, if they are each arranged at least partially in a region of the same axial coordinates.

[0027] The wheel rotation axis is also referred to as the main rotation axis of the wheel hub drive. The feature that a first component, such as the second bearing shell, is arranged radially inside a second component, such as the first bearing shell, means that the first component is arranged in a region of smaller radii, particularly relative to the wheel rotation axis. In other words, the first component is arranged further inside in the radial direction of the wheel hub drive than the second component.The feature that a first component is arranged axially within a second component is to be understood as meaning that the first component in the installation position of the wheel hub drive, which assumes an installation position in the fully manufactured state of the motor vehicle, and in particular when the motor vehicle is traveling straight ahead, i.e. when a steering system of the motor vehicle is set to cause the motor vehicle to travel straight ahead, is arranged axially on a side oriented or pointing towards the center of the vehicle, and is therefore arranged axially closer to the center of the motor vehicle, also referred to as the vehicle center, than the second component.

[0028] However, it has proven particularly advantageous if the rim and the wheel disc are formed separately from each other and connected to each other in a rotationally fixed manner, particularly in a manner that can be removed non-destructively. This allows, for example, a tire change (also known as a wheel change) to be carried out advantageously.

[0029] For example, the first bearing shell is a radially outer bearing ring of the wheel bearing, which is fixed to the wheel carrier. Thus, for example, the first bearing shell is connected to the wheel carrier in a rotationally fixed manner, in particular permanently, such that relative movements between the first bearing shell and the wheel carrier are prevented. For example, the second bearing shell is or forms a radially inner bearing ring of the wheel bearing, the radially inner bearing ring of which is arranged radially within the radially outer bearing ring of the wheel bearing.

[0030] The electric machine is preferably designed as an external rotor, i.e. as an external rotor machine, which is also referred to as an external rotor motor. This means, for example, that the stator is connected to a wheel carrier on its radially inner side. For example, at least one rotor carrier section of a rotor carrier of the electric machine is arranged radially outside the stator, wherein, for example, the rotor carrier section is also referred to as a cylinder section or as a cylinder section, thus being designed as a cylindrical section of the rotor carrier. Very preferably, the electric machine is designed as an axial flux machine (AFM), which is also referred to as an axial flux motor.

[0031] In order to realize a particularly advantageous, in particular weight-efficient design and a particularly simple assembly of the wheel hub drive, it is provided in a further embodiment of the invention that the second partial bearing is arranged axially without overlap to the friction area.

[0032] A further embodiment is characterized in that the first partial bearing is arranged axially without overlap to the stator, whereby a particularly simple assembly of the wheel hub drive can be realized.

[0033] In order to be able to assemble the wheel hub drive particularly easily, a further embodiment of the invention provides that the first partial bearing has a first shell part of the second bearing shell, wherein the first shell part is formed separately from the wheel disc and forms a first raceway for first rolling elements of the wheel bearing. The second partial bearing has a second shell part of the second bearing shell, the second shell part of which is formed separately from the wheel disc and forms a second raceway for second rolling elements of the wheel bearing, which second raceway adjoins the first raceway, in particular in the axial direction of the vehicle wheel and the wheel hub drive, wherein the second rolling elements preferably adjoin the first rolling element in the axial direction of the vehicle wheel and the wheel hub drive.The second bearing shell has a sleeve common to the shell parts, which is formed separately from the shell parts and is connected to the shell parts, in particular without screws, in a rotationally fixed manner, in particular permanently rotationally fixed. The sleeve parts are connected to the wheel disc, in particular only via the sleeve, in particular without screws, in a rotationally fixed manner, in particular permanently rotationally fixed. If the bearing shells rotate relative to one another about the wheel rotation axis, so that the sleeve and the shell parts rotate about the rotation axis relative to the first bearing shell, the first rolling elements roll, in particular directly, on the first raceway and the second rolling elements roll, in particular directly, on the second raceway.

[0034] In a further, particularly advantageous embodiment of the invention, the wheel disc is formed from a first material, and the sleeve is formed from a second material different from the first material. Preferably, the first material is or comprises aluminum. Most preferably, the first material is an aluminum alloy. Preferably, the second material is or comprises steel. In other words, the second material is preferably steel. This allows for a particularly advantageous assembly of the wheel hub drive.

[0035] For example, the shell parts are spaced apart from one another, particularly in the axial direction of the wheel hub drive. Alternatively or additionally, the shell parts are formed separately from one another and are connected to one another in a rotationally fixed manner, particularly permanently, via the sleeve and preferably without screws.

[0036] In order to be able to realize a particularly compact design and a particularly simple assembly, it is provided in a further embodiment of the invention that the second bearing shell is formed integrally with the wheel disc.

[0037] A second aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle, and preferably designed as a motor vehicle, in particular as a passenger car, whose interior, also referred to as a passenger cell or passenger compartment, is formed by a motor vehicle structure designed, for example, as a self-supporting body. The motor vehicle has at least one wheel hub drive according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0038] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments 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 alone in the figures, can be used not only in the respective combinations specified, but also in combinations or on their own, without departing from the scope of the invention.

[0039] The drawing shows: Fig. 1 shows a partial schematic longitudinal sectional view of a first embodiment of a wheel hub drive; and Fig. 2 shows a partial schematic longitudinal sectional view of a second embodiment of the wheel hub drive.

[0040] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0041] Fig. 1 shows a partial schematic longitudinal sectional view of a first embodiment of a wheel hub drive 10, also referred to as a wheel hub drive device, for a motor vehicle, also simply referred to as a vehicle. The wheel hub drive 10 has a wheel carrier 12 and a wheel bearing 14, which has a first bearing shell 16 that is connected to the wheel carrier 12, in particular permanently and in a rotationally fixed manner. As will be explained in more detail below, the wheel bearing 14 is designed as a rolling bearing. In the first embodiment, the wheel carrier 12 and the first bearing shell 16 are formed separately from one another and are connected to one another, in particular permanently and in a rotationally fixed manner. For this purpose, at least one or more screws 18 are provided, wherein the bearing shell 16 is screwed to the wheel carrier 12 by means of the screw 18 and is thereby fastened to the wheel carrier 12, in particular permanently and in a rotationally fixed manner.The wheel bearing 14 has a second bearing shell 20 arranged coaxially and rotatably with the first bearing shell 16. This means that the bearing shell 20 is arranged coaxially with the bearing shell 16 and is rotatable about a wheel rotation axis 22 relative to the bearing shell 16 and relative to the wheel carrier 12. The wheel rotation axis 22 is also referred to as the main rotation axis.

[0042] The wheel hub drive 10 also has an electric machine 24, which in the first embodiment is designed as an axial flux machine (AFM). The axial flux machine is also referred to as an axial flux motor. The electric machine 24 is designed as an external rotor. The electric machine 24 has a stator 26 and, in this case, a stator carrier 28. The stator 26 is formed separately from the wheel carrier 12 and is, in particular permanently, connected to the wheel carrier 12 in a rotationally fixed manner. The electric machine 24 also has a rotor 30 with rotor elements 32 and 34. The rotor 30 can be driven by means of the stator 26 and can therefore be rotated relative to the stator 26 via a machine rotation axis 36.

[0043] The stator carrier 28, which is formed separately from the stator 26, is connected, in particular permanently, in a rotationally fixed manner to the stator 26 and supports the stator 26. In the present case, the stator carrier 28 is formed separately from the wheel carrier 12 and, in particular permanently, in a rotationally fixed manner to the wheel carrier 12. The stator 26 is or comprises, for example, a laminated core. Furthermore, it is conceivable that the stator 26 has magnets, in particular permanent magnets, which can be held on the laminated core and thus supported by the laminated core. Furthermore, it is conceivable that the stator 26 has at least one winding which can be held on the laminated core. The stator 26 is, for example, a magnetically active element by means of which a magnetic flux is to be or is guided, which can be generated or is generated by the electrical machine 24, for example, during operation of the electrical machine, in particular in order to drive the rotor 30.In the present case, the stator carrier 28 is screwed to the wheel carrier 12 by means of the screw 18 and is thereby, in particular permanently, fastened to the wheel carrier 12 in a rotationally fixed manner.

[0044] It can be seen that the machine axis of rotation 36 coincides with the wheel axis of rotation 22, and thus with the main axis of rotation. The rotor elements 32 and 34 are spaced apart from one another in the axial direction of the electric machine 24, the radial direction of which runs perpendicular to the axial direction of the electric machine 24. The axial direction of the electric machine 24 coincides with the main axis of rotation. At least one partial region T of the stator 26 is arranged between the rotor elements 32 and 34 in the axial direction of the electric machine 24, such that the rotor element 32, viewed along the main axis of rotation and towards the rotor element 34, is at least partially overlapped by the partial region T, i.e., covered, and that the rotor element 34, viewed along the main axis of rotation and towards the rotor element 32, is at least partially overlapped by the partial region T, i.e., covered.A rotor cover is designated by 38, wherein, for example, the rotor cover 38 is a component of a rotor carrier. In particular, the rotor carrier is formed separately from the rotor 30 and, in particular permanently, is connected to the rotor 30 in a rotationally fixed manner. By driving the rotor 30, the second bearing shell 20 can be driven and thus rotated about the wheel rotation axis 22 relative to the first bearing shell 16 and relative to the wheel carrier 12.

[0045] The wheel hub drive 10 also includes a vehicle wheel 40, which has a rim 42 with a rim well 44 and a wheel disc 46. The rim 42 and the wheel disc 46 form a wheel unit of the vehicle wheel 40 or are components of the wheel unit of the vehicle wheel 40. A tire (not shown in the figures) can be mounted on the rim 42, in particular on the rim well 44, which tire is thus formed separately from the rim 42 and separately from the wheel disc 46 and is attached to the rim 42. The wheel disc 46 extends in the radial direction of the vehicle wheel 40 and thus in the radial direction of the wheel hub drive 10 as a whole, the axial direction of which runs perpendicular to the radial direction of the vehicle wheel 40 and the wheel hub drive 10, starting from the wheel bearing 14 at least up to a radial, i.e., outer, in particular outermost, edge R of the stator 26 as viewed in the radial direction of the vehicle wheel 40 and thus of the wheel hub drive 10.The axial direction of the vehicle wheel 40 coincides with the axial direction of the wheel hub drive 10 as a whole and thus with the main axis of rotation, so that the axial direction of the wheel hub drive 10 coincides with the main axis of rotation, i.e., runs along the main axis of rotation. The radial direction of the vehicle wheel 40 coincides with the radial direction of the wheel hub drive 10, wherein the radial direction of the vehicle wheel 40 and thus of the wheel hub drive as a whole is illustrated by a double arrow 48 and runs perpendicular to the axial direction of the vehicle wheel 40 and the wheel hub drive 10 and thus perpendicular to the main axis of rotation.

[0046] In the first embodiment, which is shown in Fig. 1, the wheel disc 46 extends radially outward from the wheel bearing 14 over the radially outer, in particular outermost, edge of the stator 26. The stator 26 ends at its outer, in particular outermost, edge, viewed outward in the radial direction of the wheel hub drive 10. Furthermore, the wheel disc 46 is connected to the second bearing shell 20 in a screwless and permanently rotationally fixed manner.

[0047] At the Fig. In the first embodiment shown in Figure 1, the second bearing shell 20 and the second wheel disc 46 are formed integrally with one another, thus formed from a single piece.

[0048] The wheel bearing 14 has first rolling elements 50, which form, for example, a first row of rolling elements. The wheel bearing 14 has second rolling elements 52, which form, for example, a second row of rolling elements. The rolling elements 52 follow the rolling elements 50 in the axial direction of the wheel hub drive 10, so that the second row of rolling elements follows the first row of rolling elements in the axial direction of the wheel hub drive 10. The bearing shell 16 forms a first raceway L1 for the rolling elements 50 and a second raceway L2 for the rolling elements 52, wherein the second raceway L2 follows the first raceway L1 in the axial direction of the wheel hub drive 10. The second bearing shell 20 forms a third raceway L3 for the rolling elements 50 and a fourth raceway L4 for the rolling elements 52, wherein the fourth raceway L4 follows the third raceway L3 in the radial direction of the wheel hub drive 10.If the bearing shells 16 and 20 rotate relative to each other about the main axis of rotation, the rolling elements 50 roll directly on the raceways L1 and L3, and the rolling elements 52 roll directly on the raceways L2 and L4, whereby rolling of the rolling elements 50 on the raceways L2 and L4 is omitted and rolling of the rolling elements 52 on the raceways L1 and L3 is omitted.

[0049] The rotor elements 32 and 34 are, for example, disc-shaped and thus designed as rotor discs of the rotor 30.

[0050] In order to achieve a particularly lightweight design and particularly low assembly effort for the wheel hub drive 10, the second bearing shell 20 is arranged radially inside the first bearing shell 16.

[0051] The wheel hub drive 10 also has a fastening ring 54, which in this case is formed integrally with the wheel disc 46. As a result, the fastening ring 54 is connected, in particular permanently, in a rotationally fixed manner to the wheel disc 46. The fastening ring 46 is arranged radially, ie in the radial direction of the wheel hub drive 10 and thus of the vehicle wheel 40, outside the stator 26. In addition, the fastening ring 54 has openings, of which Fig. 1, an opening designated 56 can be seen. The opening 56 is designed as a through-opening which, for example, completely penetrates the fastening ring 54 in the axial direction of the wheel hub drive 10. A respective screw 58 is received, in particular precisely, in the respective opening. By means of the screws 58, the rim 42 is fastened to the wheel disc 46, in particular in a non-destructively detachable manner, in particular in such a way that the rim 42 is connected to the wheel disc 46 in a rotationally fixed manner and very preferably in such a way that relative movements between the rim 42 and the wheel disc 46 are prevented.

[0052] In Fig. 1 is particularly schematically shown at least one line element 60, via which, for example, the rotor 30 can be supplied with electrical energy, in particular in order to drive the rotor 30.

[0053] The wheel hub drive 10 also has a braking device 62 designed to brake the vehicle wheel 40, which in the first embodiment is designed as a disc brake. The braking device 62 has a first friction element 64, which in the present case is designed as a brake caliper. The friction element 64 is connected, in particular permanently, in a rotationally fixed manner to the wheel carrier 12. The braking device 62 has a second friction element 66, which is connected, in particular permanently, in a rotationally fixed manner to the wheel disc 46. The braking device 62 also has a friction region B, in which the friction elements 64 and 66 can be brought into, in particular direct, frictional, i.e. frictionally engaged interaction, in order to brake the wheel disc 46 and thus the vehicle wheel 40 with regard to their respective rotation about the main axis of rotation and relative to the bearing shell 16 and the wheel carrier 12.

[0054] Fig.2 shows a partial schematic longitudinal sectional view of a second embodiment of the wheel hub drive 10. In the second embodiment, the wheel bearing 14 is formed in two parts. The wheel bearing 14 has a first partial bearing 68 and a second partial bearing 70, which are spaced apart from one another and arranged one after the other, for example in the axial direction of the wheel hub drive 10. The first partial bearing 68 is arranged so as to axially overlap the friction region B. The second partial bearing 70 is arranged so as to axially overlap the stator 26 and, for example, so as to axially overlap free from the friction region B. Furthermore, the first partial bearing 68 is arranged so as to axially overlap free from the stator 26. The first partial bearing 68 has a first shell part 72 of the second bearing shell 20, the first shell part 72 of which is formed separately from the wheel disc 46 and forms the raceway L3 for the rolling elements 50.The second partial bearing 70 has a second shell part 74 of the second bearing shell 20, the second shell part 74 of which is formed separately from the wheel disc 46 and forms the raceway L4 for the rolling elements 52. The shell parts 72 and 74 are formed separately from one another in the present case. The second bearing shell 20 has a sleeve 76 which is common to the shell parts 72 and 74, separate from the shell parts 72 and 74 and, in the present case, is connected to the shell parts 72 and 74 in a screw-free, non-rotatable manner, in particular permanently non-rotatable, manner. The sleeve 76 is formed separately from the wheel disc 46 and is connected to the wheel disc 46 in a screw-free, non-rotatable manner, in particular permanently non-rotatable, manner. The disc parts 72 and 74 are, in particular only, connected to the wheel disc 46 in a rotationally fixed and, in this case, screw-free manner and, in particular, screw-free manner, permanently connected to the wheel disc 46.Preferably, the bearing shell 16 is formed in one piece, i.e. from a single piece.

[0055] In the second embodiment, the wheel disc 46 is formed from a first material, which is, for example, an aluminum alloy. The sleeve 76 is formed from a second material different from the first material, which is preferably steel. Thus, the sleeve 76 is preferably formed as a steel sleeve, while the wheel disc 46 is preferably formed as an aluminum wheel disc. List of reference symbols 10 Wheel hub drive 12 wheel carriers 14 wheel bearings 16 first bearing shell 18 screw 20 second bearing shell 22 Wheel rotation axis 24 electric machine 26 Stator 28 stator carriers 30 rotors 32 Rotor element 34 Rotor element 36 Machine rotation axis 38 rotor cover 40 vehicle wheel 42 rim 44 rim base 46 Wheel disc 48 double arrow 50 first rolling elements 52 second rolling element 54 Mounting ring 56 Opening 58 screw 60 line 62 Braking device 64 first friction element 66 second friction element 68 first sub-warehouse 70 second sub-warehouse 72 first shell part 74 second shell part B Friction area L1 first career L2 second career L3 third career L4 fourth career R edge T sub-area 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] WO 2022 / 096504 A1

[0002]

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (12), a wheel bearing (14) having a first bearing shell (16) connected in a rotationally fixed manner to the wheel carrier (12) and a second bearing shell (20) arranged coaxially and rotatably relative to the first bearing shell (16), an electric machine (24) having a stator (26) connected in a rotationally fixed manner to the wheel carrier (12) and a rotor (30) by means of which the second bearing shell (20) can be driven and is thereby rotatable relative to the first bearing shell (16), a vehicle wheel (40) having a rim (42) and a wheel disc (46) extending outwardly in the radial direction (48) of the vehicle wheel (40) from the wheel bearing (14) at least to a radially outer edge (R) of the stator (26) and being connected to the second bearing shell (20) in a screw-free and permanently rotationally fixed manner, characterized by that the second bearing shell (20) is arranged radially inside the first bearing shell (16). [2] Wheel hub drive (10) according to claim 1, characterized by a fastening ring (54) which is connected to the wheel disc (46) in a rotationally fixed manner, is arranged radially outside the rotor (30) and radially outside the stator (26) and has openings (56) in which screws (58) are received, by means of which the rim (42) is fastened to the wheel disc (46). [3] Wheel hub drive (10) according to claim 1 or 2, characterized by that a braking device (62) designed to brake the vehicle wheel (40) is provided, which has friction elements (64, 66) and a friction region (B) in which the friction elements (64, 66) of the braking device (62) can be brought into frictional interaction in order to thereby brake the vehicle wheel (40). [4] Wheel hub drive (10) according to claim 3, characterized by , that: - the wheel bearing (14) has a first partial bearing (68) and a second partial bearing (70); - the first partial bearing (68) is arranged axially overlapping the friction region (B) of the braking device (62); and - the second partial bearing (70) is arranged axially overlapping the stator (26). [5] Wheel hub drive (10) according to claim 4, characterized by that the second partial bearing (70) is arranged axially without overlap to the friction area (B). [6] Wheel hub drive (10) according to claim 4 or 5, characterized by that the first partial bearing (68) is arranged axially without overlap with the stator (26). [7] Wheel hub drive (10) according to one of claims 4 to 6, characterized by , that: - the first partial bearing (68) has a first switching part (72) of the second bearing shell (20), the first shell part (72) of which is formed separately from the wheel disc (46) and forms a first raceway (L3) for first rolling elements (50) of the wheel bearing (14); - the second partial bearing (70) has a second switching part (74) of the second bearing shell (20), the second shell part (74) of which is formed separately from the wheel disc (46) and forms a second raceway (L4) for second rolling elements (52) of the wheel bearing (14); - the second bearing shell (20) has a sleeve (76) common to the shell parts (72, 74), formed separately from the shell parts (72, 74) and connected in a rotationally fixed manner to the shell parts (72, 74), which sleeve is formed separately from the wheel disc (46) and connected in a rotationally fixed manner to the wheel disc (46); and - the shell parts (72, 74) are connected to the wheel disc (46) in a rotationally fixed manner by means of the sleeve (76). [8] Wheel hub drive (10) according to claim 7, characterized by that the wheel disc (46) is formed from a first material and the sleeve (76) is formed from a second material different from the first material. [9] Wheel hub drive (10) according to one of claims 1 to 7, characterized by that the second bearing shell (20) is formed integrally with the wheel disc (46). [10] Motor vehicle, with at least one wheel hub drive (10) according to one of the preceding claims.

Images