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 (12), a wheel bearing (14) which has a first bearing shell (16) connected in a rotationally fixed manner to the wheel carrier (12) and a second bearing shell (20) arranged coaxially to the first bearing shell (16) and rotatable about a wheel rotation axis (22), an electric machine (24) which has 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) which has a rim (42) and a wheel disc (46), wherein a fastening ring (54) is provided which is connected in a rotationally fixed manner to the rotor (30) and arranged radially outside the rotor (30) with respect to the wheel rotation axis (22), wherein the rim (42) is arranged by means of third screws (58) are connected to the fastening ring (54) in a rotationally fixed manner.

Description

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

[0002] WO 2022 / 096504 A1 discloses a wheel system for a vehicle, comprising a stator, a rotor and a rotary bearing, wherein a rim of a vehicle wheel is formed separately from a wheel disc.

[0003] The object of the present invention is to provide a wheel hub drive for a motor vehicle 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. 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] The wheel disc is connected to the second bearing shell in a rotationally fixed manner.

[0011] The wheel disc and the rim are connected to each other in a rotationally fixed manner. By driving the second bearing shell, i.e., by rotating the second bearing shell around the wheel's axis of rotation and relative to the first bearing shell, the wheel disc and, for example, the rim and thus, for example, the tire, can be driven via the wheel disc, whereby the vehicle, in particular the motor vehicle, can be driven, in particular purely electrically, by means of the rotor.

[0012] In a manner known from the prior art, a fastening ring is provided which is connected to the rotor in a rotationally fixed manner and is arranged radially outside the rotor with respect to the wheel rotation axis, wherein the rim is connected to the fastening ring in a rotationally fixed manner by means of third screws arranged radially outside the rotor.

[0013] The rim and wheel disc are thus advantageously designed as separate and detachable components. When changing tires, the rim can be removed from the vehicle alone, allowing the fixed wheel disc to perform additional functions.

[0014] In order to be able to realize a particularly weight-efficient design of the wheel hub drive as well as a particularly simple assembly of the wheel hub drive, it is provided according to the invention that the electric machine is designed as an axial flux machine, wherein first rotor magnets are arranged on a side of the wheel disc axially facing the stator.

[0015] Because the electric machine is designed as an axial flux machine, the wheel disc is designed separately from the rim, and the first rotor magnets are arranged on the wheel disc, the wheel hub drive can be designed to be particularly compact, lightweight, and easy to install. The wheel disc has areas that belong both to the wheel disc and to a rotor carrier of the electric machine. In other words, the wheel disc partially assumes the function of a part of the rotor carrier.

[0016] The term "third screws" is not intended to imply that the wheel hub drive also includes first and second screws. The terms "first," "second," "third," etc., also known as ordinals, are intended merely to unambiguously designate elements, not to specify a number of such elements.

[0017] Rotor magnets are magnets that belong to the rotor. Advantageously, the rotor has two rotor segments, which are arranged on both axial sides of the stator with respect to an axial direction along the wheel rotation axis. The first rotor magnets are parts of the first rotor segment, which is arranged between the stator and the wheel disc. The first rotor magnets are arranged on an axially inner side of the wheel disc in such a way that there is no air gap between the wheel disc and the first rotor magnets.

[0018] An advantageous development of the invention provides a rotor cover that is arranged axially on a side of the stator facing away from the wheel disc with respect to the wheel rotation axis and is connected to the wheel disc in a rotationally fixed manner by means of fourth screws. Second rotor magnets are arranged on the rotor cover. This further improves the ease of assembly and cost-effectiveness of the wheel hub drive.

[0019] The second rotor magnets are part of the second rotor segment. The second rotor segment is thus attached to the rotor cover and can be removed from the first rotor segment together with the rotor cover or mounted on the first rotor segment. The rotor cover is arranged axially between the stator and the wheel carrier.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 formed separately from the wheel carrier and, in particular, is permanently connected to the wheel carrier in a rotationally fixed manner.

[0024] In the further embodiment, it is advantageously provided that the friction region is arranged axially between the wheel carrier and the stator and radially overlapping the stator. In a further development of this further embodiment, a connecting element is particularly advantageously provided which is designed to directly connect the second friction element to the rotor cover. The connecting element is advantageously directly connected to the second friction element and directly connected to the rotor cover. Particularly advantageously, the connecting element is arranged radially inside the second friction element and connected to the rotor cover at a radially innermost edge of the rotor cover.

[0025] A further development of the invention provides that the second bearing shell is arranged radially inside the first bearing shell.

[0026] 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 cannot 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.

[0027] The feature that two components are connected or coupled to one another in a torque-transmitting manner is to be understood as meaning that the components are coupled or connected to one another in such a way that torques can be transmitted between the components, wherein 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.

[0028] 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 for two components connected to one another in a torque-transmitting manner to be connected to one another 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.

[0029] 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.

[0030] 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.

[0031] 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 also 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.

[0032] 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.

[0033] 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.

[0034] 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, i.e. as a cylindrical section of the rotor carrier. The rotor carrier is connected to the rotor in a rotationally fixed manner. The electric machine is designed as an axial flux machine (AFM), which is also referred to as an axial flux motor.

[0035] 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.

[0036] Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing.

[0037] The drawing shows in the single figure a partial schematic longitudinal sectional view of a wheel hub drive 10 according to the invention for a motor vehicle not shown in detail here.

[0038] 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, 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 embodiment according to the invention, the wheel carrier 12 and the first bearing shell 16 are formed separately from one another and are connected to one another in a rotationally fixed manner. For this purpose, at least one or more first screws 18 are provided, wherein the first bearing shell 16 is screwed to the wheel carrier 12 by means of the first screws 18 and is thereby fastened to the wheel carrier 12 in a rotationally fixed manner. The wheel bearing 14 has a second bearing shell 20 arranged coaxially and rotatably to the first bearing shell 16. This means that the second bearing shell 20 is arranged coaxially to 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 called the main rotation axis.

[0039] The wheel hub drive 10 also includes an electric machine 24, which is configured as an axial flux machine (AFM). The axial flux machine is also referred to as an axial flux motor. The electric machine 24 is configured as an external rotor. The electric machine 24 includes a stator 26 and, in this case, a stator carrier 28. The stator 26 is configured separately from the wheel carrier 12 and is rotationally fixedly connected to the wheel carrier 12 by means of the stator carrier 28.

[0040] Advantageously, the stator 26 is screwed to the wheel carrier 12 by means of the first screws 18 together with the first bearing shell 16. For this purpose, the stator carrier 28 is particularly advantageously screwed directly to the wheel carrier 12 by means of the first screws 18 together with the first bearing shell 16.

[0041] The electric machine 24 also has a rotor 30 with first rotor magnets 32 and second rotor magnets 34. The rotor 30 can be driven by the stator 26 and is thus rotatable relative to the stator 26 via a machine rotation axis 36.

[0042] The stator carrier 28, which is formed separately from the stator 26, is connected, in particular permanently, to the stator 26 in a rotationally fixed manner and supports the stator 26. In the present case, the stator carrier 28 is formed separately from the wheel carrier 12 and is connected to the wheel carrier 12 in a rotationally fixed manner. The stator 26 comprises, for example, a holding structure and at least one winding, which can be held on the holding structure. The stator 26 is, for example, a magnetically active element by means of which a magnetic flux is to be or is guided, which, for example, can be or is generated by the electric machine 24 during operation of the electric machine, in particular in order to thereby drive the rotor 30.

[0043] It can be seen that the machine rotation axis 36 coincides with the wheel rotation axis 22, thus with the main rotation axis. The rotor magnets 32 and 34 are spaced apart from each other in the axial direction of the electric machine 24, whose radial direction runs perpendicular to the axial direction of the electric machine 24. The axial direction of the electric machine 24 coincides with the main rotation axis.

[0044] Generally, terms such as “axial” and “radial” in this disclosure refer to the main axis of rotation unless otherwise noted.

[0045] At least a partial region T of the stator 26 is arranged in the axial direction of the electric machine 24 between the rotor magnets 32 and 34. The first rotor magnets 32 and the second rotor magnets 34 are arranged radially overlapping the partial region T of the stator 26 with respect to the main axis of rotation.

[0046] A rotor cover is designated by 38, wherein, for example, the rotor cover 38 is a component of a rotor carrier 31. In particular, the rotor carrier 31 is formed separately from the rotor 30 and 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.

[0047] The wheel hub drive 10 also includes a vehicle wheel 40, which has a rim 42 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 figure) can be mounted on the rim 42, which tire is thus formed separately from the rim 42 and separate 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 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.

[0048] In the embodiment shown in the figure, the wheel disc 46 extends radially outwardly from the wheel bearing 14 over the radially outer, in particular outermost, edge R of the stator 26. The stator 26 ends at its outer, in particular outermost, edge R, viewed outwardly in the radial direction of the wheel hub drive 10. Furthermore, the wheel disc 46 is connected to the second bearing shell 20 by means of second screws 44.

[0049] In a further embodiment not shown here, the second bearing shell 20 and the second wheel disc 46 are formed integrally with one another, thus formed from a single piece.

[0050] 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 first 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.

[0051] 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.

[0052] The wheel hub drive 10 also has a fastening ring 54, which is non-rotatably connected to the rotor 30. The fastening ring 54 is non-rotatably connected to the rotor carrier 31. Advantageously, the fastening ring 54 is formed integrally with a part 39 of the rotor carrier 31, which means that the fastening ring 54 is connected to the part 39 of the rotor carrier 31 without screws.

[0053] The fastening ring 54 is connected to the wheel disc 46 in a rotationally fixed manner. Particularly advantageously, the fastening ring 54, the wheel disc 46, and the part 39 of the rotor carrier 31 are formed integrally with one another.

[0054] The fastening ring 46 is advantageously 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 third screw 58 is received, in particular precisely, in the respective opening. By means of the third screws 58, the rim 42 is fastened, in particular in a non-destructively detachable manner, to the wheel disc 46 and to the rotor carrier 31, in particular in such a way that the rim 42 is connected in a rotationally fixed manner to the wheel disc 46 and the rotor 30, in such a way that relative movements between the rim 42 and the wheel disc 46 are prevented.

[0055] Advantageously, the first rotor magnets 32 are arranged on the wheel disc 46. In the exemplary embodiment shown here, the part 39 of the rotor carrier 31 is formed integrally with the wheel disc 46. However, it is essential that the first rotor magnets 32 are connected to an axial inner side of the wheel disc 46 in such a way that there is no air gap between the wheel disc 46 and the first rotor magnets 32. The axial inner side refers to the side of the wheel disc facing the stator in the axial direction.

[0056] The rotor cover 38 of the rotor carrier 31 is advantageously formed separately from the part 39 of the rotor carrier 31. The rotor cover 38 is arranged axially on a side of the stator 26 facing away from the wheel disc 46. The second rotor magnets 34 are advantageously arranged, with respect to the axial direction, on a side of the rotor cover 38 facing the stator 26.

[0057] Advantageously, the rotor cover 38 is connected to the part 39 in a rotationally fixed manner by means of fourth screws 68. The part 39 advantageously has a cylindrical section arranged radially outside the stator 26 and axially overlapping the stator 26. Particularly advantageously, the fourth screws 68 are arranged radially overlapping the cylindrical section. The rotor cover 38 is thus also connected to the wheel disc 46 in a rotationally fixed manner by means of the fourth screws 68. The fourth screws 68 are arranged axially between the fastening ring 54 and the braking device 62.

[0058] The rotor cover 38 advantageously has a plate shape, the radially outermost edge of which is arranged radially overlapping the cylinder section and which extends radially inward from the cylinder section towards the machine rotation axis 36.

[0059] Particularly schematically shown in the figure is at least one conducting element 60, via which the rotor 30 can be supplied with electrical energy, in particular to thereby drive the rotor 30. The conducting element 60 is advantageously arranged at least partially within the stator carrier 28.

[0060] 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 first 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.The friction region B is advantageously arranged axially between the wheel carrier 12 and the stator 26. Furthermore, the friction region B is advantageously arranged at least partially radially overlapping the stator 26.

[0061] Advantageously, a connecting element 70 is provided for directly connecting the second friction element 66 to the rotor cover 38. Advantageously, the connecting element 70 is arranged radially within the second friction element 66. Advantageously, the connecting element 70 is arranged axially between the rotor cover 38 and the wheel carrier 12. List of reference symbols 10 Wheel hub drive 12 wheel carriers 14 wheel bearings 16 first bearing shell 18 First screws 20 second bearing shell 22 Wheel rotation axis 24 electric machine 26 Stator 28 stator carriers 30 rotors 31 rotor carrier 32 First rotor magnets 34 Second rotor magnets 36 Machine rotation axis 38 rotor cover Part 39 40 vehicle wheel 42 rim 44 Second screws 46 Wheel disc 48 double arrow 50 first rolling elements 52 second rolling element 54 Mounting ring 56 Opening 58 Third screw 60 line element 62 Braking device 64 first friction element 66 second friction element 68 Fourth screws 70 connecting element 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 with a wheel carrier (12), with a wheel bearing (14) which has a first bearing shell (16) connected in a rotationally fixed manner to the wheel carrier (12) and a second bearing shell (20) arranged rotatably about a wheel rotation axis (22) relative to the first bearing shell (16), with an electric machine (24) which has 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), with a vehicle wheel (40) which has a rim (42) and a wheel disc (46), wherein a fastening ring (54) is provided which is connected in a rotationally fixed manner to the rotor (30) and arranged radially outside the rotor (30) with respect to the wheel rotation axis (22), wherein the rim (42) is fastened by means of third screws arranged radially outside the rotor (30) (58) is connected to the fastening ring (54) in a rotationally fixed manner, characterized bythat the electrical machine (24) is designed as an axial flux machine, wherein first rotor magnets (32) are arranged on a side of the wheel disc (46) axially facing the stator (26). [2] Wheel hub drive (10) according to claim 1, characterized by a rotor cover (38) which is arranged axially on a side of the stator (26) facing away from the wheel disc (46) with respect to the wheel rotation axis (22) and is connected to the wheel disc in a rotationally fixed manner by means of fourth screws (68), wherein second rotor magnets (34) are arranged on the rotor cover (38). [3] Wheel hub drive (10) according to claim 1 or 2, characterized bythat a braking device (62) is provided which is designed to brake the vehicle wheel (40), said braking device having a first friction element (64) and a second friction element (66), wherein in a friction region (B) 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), wherein the friction region (B) is arranged axially between the wheel carrier (12) and the stator (26) and radially overlapping the stator (26). [4] Wheel hub drive (10) according to claims 2 and 3, characterized by that a connecting element (70) is designed for the direct connection of the second friction element (66) to the rotor cover (38). [5] Wheel hub drive (10) according to one of the preceding claims, characterized by that the second bearing shell (20) is arranged radially inside the first bearing shell (16). [6] Wheel hub drive (10) according to one of the preceding claims, characterized bythat the stator (26) is screwed to the wheel carrier (12) by means of first screws (18) together with the first bearing shell (16).

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