Wheel hub drive for a motor vehicle, as well as motor vehicle

Abstract

The invention relates to a wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (12), a wheel hub (40) rotatably mounted on the wheel carrier (12) via a wheel bearing (14), a vehicle wheel (42) which is connected to the wheel hub (40) in a rotationally fixed manner, an electric machine (24) which has a stator (26) connected to the wheel carrier (12) in a rotationally fixed manner and a rotor (30) which can be driven by means of the stator (26) and is thereby rotatable relative to the stator (26), which rotor is rotatably mounted on the wheel carrier (12) via a rotor bearing (58) provided in addition to the wheel bearing (14), and a positive coupling device (K) which can be switched between a coupling state in which the rotor (30) is connected to the wheel hub (40) in a rotationally fixed manner by means of the coupling device (K), and a decoupling state in which the rotor (30) is relative to the Wheel hub (40) is rotatable.

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] DE 10 2022 000 026 A1 states that a wheel hub drive for a motor vehicle is known.

[0003] The object of the present invention is to provide a wheel hub drive for a motor vehicle and a motor vehicle with at least one such wheel hub drive, so that particularly efficient operation can be achieved in a particularly space-saving manner. This object is achieved by a wheel hub drive with the features of patent claim 1 and by a motor vehicle with the features of patent claim 12. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0004] 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. In this case, preferably, in particular exactly a first of the vehicle wheels is 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, which comprises the vehicle wheel. 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, comprise, in particular, exactly a second of the vehicle wheels, whereby the second vehicle wheel can be driven, in particular purely electrically, by means of the wheel hub drive.In this case, it is preferably provided that the first vehicle wheel and the second vehicle wheel are the vehicle wheels of the same vehicle axle. The previous and following statements regarding the first wheel hub drive and the first vehicle wheel can also be readily applied to the second wheel hub drive and the second vehicle wheel, and vice versa.

[0005] The wheel hub drive (first wheel hub drive) has a wheel carrier and a wheel hub, which is rotatably mounted on the wheel carrier via a wheel bearing of the wheel hub drive. For example, the wheel bearing 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 relative to the first bearing shell and, for example, is connected to the wheel hub, in particular permanently and in a rotationally fixed manner. Thus, the wheel hub and in particular the second bearing shell are rotatably mounted on the wheel carrier, in particular via the first bearing shell, about a wheel rotation axis also referred to as the main axis of rotation relative to the wheel carrier and in particular relative to the first bearing shell. The wheel bearing is preferably designed as a rolling bearing. In principle, it would be conceivable for the first bearing shell to be separate from the wheel carrier and, in particular permanently, in a rotationally fixed manner to the wheel carrier.Furthermore, it would be conceivable for the first bearing shell and the wheel carrier to be formed integrally with one another, i.e. from a single piece. In principle, it would be conceivable for the wheel hub and the second bearing shell to be formed separately from one another and, in particular, permanently and non-rotatably connected to one another. Furthermore, it would be conceivable for the second bearing shell and the wheel hub to be formed integrally with one another and thus formed from a single piece and, as a result, in particular, permanently and non-rotatably connected to one another. In the context of the present disclosure, the feature that two components, such as the second bearing shell and the wheel hub, are formed integrally with one another, is to be understood as meaning that the components formed integrally with one another 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 the components are formed from a single piece, that is to say by a body formed from a single piece and thus formed in one piece, that is to say integrally manufactured, which is a monoblock.

[0006] For example, the wheel bearing has rolling elements. For example, the first bearing shell forms at least one first raceway for the rolling elements, and the second bearing shell forms, for example, at least one second raceway for the rolling elements. In particular, when the wheel hub rotates about the main axis of rotation relative to the wheel carrier and thus the second bearing shell rotates about the wheel 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 in each case, so that, for example, the rolling elements contact the first raceway and the second raceway, in particular directly in each case.

[0007] The (first) vehicle wheel of the wheel hub drive is non-rotatably connected to the wheel hub, so that the vehicle wheel is mounted on the wheel carrier via the wheel hub and the wheel bearing, allowing it to rotate about the main axis of rotation relative to the wheel carrier. The wheel hub and the wheel bearing are mounted on the wheel carrier, allowing it to rotate about the main axis of rotation relative to the wheel carrier.

[0008] The wheel hub drive also has an electric machine which has a stator, which is in particular permanently and non-rotatably connected to the wheel carrier, and a rotor. The rotor can be driven by means of the stator and can therefore be rotated relative to the stator, in particular about a machine axis of rotation. Preferably, the rotor is arranged coaxially to the wheel bearing or the bearing shells, so that the machine axis of rotation preferably coincides with the wheel axis of rotation (main axis of rotation). By driving the rotor, the wheel hub, in particular the second bearing shell and, via the second bearing shell, the wheel hub, can be driven by means of the rotor, whereby the wheel hub and thus the vehicle wheel can be rotated about the main axis of rotation relative to the wheel carrier and in particular relative to the first bearing shell.

[0009] The vehicle wheel comprises, for example, a rim and a wheel disc. A tire, which may be a component of the vehicle wheel and is made of rubber and separate from the wheel disc and the rim, is mounted on the rim and thus secured to the rim. In particular, when the vehicle wheel rolls, in particular directly, on the aforementioned ground, the tire rolls or rolls, in particular directly, on the ground.

[0010] The rotor is rotatably mounted on the wheel carrier via a rotor bearing provided in addition to the wheel bearing and thus designed, for example, as a rolling bearing, so that the rotor is rotatably mounted on the wheel carrier about the machine axis of rotation, in particular about the main axis of rotation, relative to the wheel carrier via the wheel bearing. The wheel hub drive also has a positive coupling device which can be switched between a coupled state and a decoupling state. In the coupled state, the rotor is positively connected to the wheel hub in a rotationally fixed manner by means of the coupling device, so that in the coupled state the rotor can drive the wheel hub and, via the wheel hub, the vehicle wheel. In the decoupling state, the rotor is decoupled from the wheel hub and can consequently rotate relative to the wheel hub, in particular about the machine axis of rotation and very particularly about the main axis of rotation.In other words, in the uncoupling state, the coupling device releases the rotor for rotations around the main axis of rotation and relative to the wheel hub, and vice versa. If the coupling device is in the uncoupling state, no torque can be transmitted between the wheel hub and the rotor via the coupling device. If, for example, the motor vehicle is in its overrun mode while the coupling device is in the uncoupling state, the rotating vehicle wheel, for example, does not drag the rotor along, so that, for example, efficient operation can be achieved. It can be seen that the coupling device functions, is designed, or can be operated as a mechanical separation unit, whereby the separation unit is also referred to as a disconnect unit or separation unit or decoupling unit.In the coupled state, the wheel hub and the rotor are positively connected to each other by means of the coupling unit, which also enables particularly advantageous, efficient operation.

[0011] In order to further realize a particularly compact design of the wheel hub drive, the invention provides that the coupling device has a coupling element extending in a radial direction of the wheel hub drive, the axial direction of which is perpendicular to the radial direction of the wheel hub drive, and arranged so as to be displaceable along the radial direction of the wheel hub drive relative to the wheel hub and relative to the rotor, thus displaceable and thus translationally movable. The axial direction of the wheel hub drive runs along the main axis of rotation or coincides with the main axis of rotation, so that the radial direction of the wheel hub drive runs perpendicular to the main axis of rotation.

[0012] The coupling element is thus displaceable in the radial direction of the wheel hub drive relative to the wheel hub and relative to the rotor between at least one coupling position bringing about the coupling state and at least one decoupling position bringing about the decoupling state. This means that the coupling device is in its coupling state when and in particular whenever the coupling element is in its coupling position. Furthermore, for example, the coupling device is in its decoupling state when and preferably whenever the coupling element is in its decoupling position. For example, an actuator is provided by means of which the coupling element is displaceable relative to the wheel hub and relative to the rotor between the coupling position and the decoupling position in the radial direction of the wheel hub drive.When reference is made above and below to the axial direction, this means the axial direction of the wheel hub drive, unless otherwise stated. When reference is made above and below to the radial direction, this means the radial direction of the wheel hub drive, unless otherwise stated. In the context of the present disclosure, the term "radial" refers to the radial direction of the wheel hub drive, and the term "axial" refers to the axial direction of the wheel hub drive. In other words, the term "radial" means the radial direction of the wheel hub drive, whereas the term "axial" means the axial direction of the wheel hub drive.

[0013] For example, it is provided that the coupling element in the coupling position interacts positively with both the wheel hub and the rotor, so that in the coupled state the rotor and the wheel hub are positively connected to one another in a rotationally fixed manner by means of the coupling element. In the uncoupling position the coupling element does not interact positively with both the rotor and the wheel hub, but for example the coupling element in the uncoupling position interacts exclusively with the rotor or exclusively with the wheel hub with respect to the rotor and the wheel hub, or in the uncoupling position the coupling element interacts neither positively with the rotor nor with the wheel hub, so that in the uncoupling position and thus in the uncoupling state of the coupling device the rotor and the wheel hub are decoupled from one another and can therefore rotate relative to one another about the main axis of rotation.Because in the invention the coupling element can be displaced radially, i.e. in the radial direction of the wheel hub drive between the coupling position and the decoupling position, a particularly space-saving design of the wheel hub drive can be realized.

[0014] In order to be able to realize a particularly compact design of the wheel hub drive, one embodiment of the invention provides that the coupling element is permanently connected to the wheel hub in a rotationally fixed manner, at least with respect to the main axis of rotation, also simply referred to as the axis of rotation, about which the wheel hub and thus the vehicle wheel can rotate relative to the wheel carrier. Thus, for example, the coupling element interacts positively with the wheel hub both in the coupling position and in the decoupling position, such that the coupling element is permanently connected to the wheel hub in a rotationally fixed manner, at least with respect to the main axis of rotation. In the coupling position, for example, the coupling element also interacts positively with the rotor, whereby, for example, in the decoupling position, the coupling element does not interact positively with the rotor.

[0015] Another embodiment is characterized by the coupling element being arranged axially overlapping the rotor bearing. This allows the brake pad wear of the wheel hub drive to be kept particularly low.

[0016] The feature “axially overlapping” is to be understood as follows: Two elements such as the coupling element and the rotor bearing 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.

[0017] In the context of the present disclosure, the feature "radially overlapping" is to be understood as follows: Two, in particular at least substantially rotationally symmetrical elements are arranged radially, in particular with respect to one another, in particular with respect to a common axis, for example, extending 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. In the context of the present disclosure, the feature that a first component is arranged radially within a second component is to be understood as meaning that the first component is arranged in a region of smaller radii than the second component, in particular with respect to the main axis of rotation. Furthermore, the feature that a first component is arranged axially within a second component is to be understood as meaningthat in the installed position of the wheel hub drive, which assumes its installed position in the fully manufactured state of the motor vehicle having the wheel hub drive and in particular with respect to straight-ahead travel of the motor vehicle, that is to say in particular when a steering system of the motor vehicle is set to cause the motor vehicle to travel straight ahead, the first component, which is arranged axially within the second component, is arranged on one side of the second component towards a centre of the motor vehicle, also referred to as the vehicle centre, thus the first component is arranged on a side of the second component pointing towards the centre of the motor vehicle, so that the first component is arranged further inwards, that is to say closer to the centre of the motor vehicle, than the second component, in particular when viewed in the transverse direction of the motor vehicle.

[0018] In the context of the present disclosure, the feature that two components 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 main rotation axis, at the same angular velocity, in particular relative to a reference element, such as the 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 at 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, an element is connected to the wheel carrier in a rotationally fixed manner if it cannot be rotated relative to the wheel carrier.

[0019] 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.

[0020] The feature that two components are permanently connected or coupled to one another in a torque-transmitting manner does not mean that a switching element is 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.

[0021] In particular, the feature that two components 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 that 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 rotatable relative to one another, so that no torque can be transmitted between the components via the switching element. Instead, the components are always connected or coupled to one another, and therefore permanently connected or coupled to one another in a rotationally fixed manner. Furthermore, the feature that two components can be connected or coupled to one another in a rotationally fixed manner is to be understood as meaning that the components are assigned a switching element which can be switched between at least one coupling state and at least one decoupling state.In the coupled state, the components are connected or coupled to one another in a rotationally fixed manner by means of the switching element. In the uncoupled state, the components are decoupled from one another such that in the uncoupled 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 such that torques can be transmitted between the components, in particular via the switching element.In the release state, the components are decoupled from each other, so that in the release state no torque can be transmitted between the components via the switching element.

[0022] In order to be able to realize a particularly compact design of the wheel hub drive, it is provided in a further embodiment of the invention that the coupling element radially penetrates the rotor bearing.

[0023] A further embodiment is characterized in that a rotor carrier section of a wheel carrier carrying the rotor is arranged so as to axially overlap the rotor bearing, as a result of which, in particular, an axial length of the wheel hub drive can be kept particularly short. In particular, it is provided, for example, that the rotor is formed separately from the wheel carrier and is connected, in particular permanently, to the wheel carrier in a rotationally fixed manner. In particular, the rotor is or comprises, for example, a laminated core, also referred to as a rotor laminated core. Alternatively or additionally, the rotor can comprise at least one or more magnets, in particular permanent magnets, which are held, for example, on the rotor laminated core and are thus carried by the rotor laminated core.Alternatively or additionally, the rotor can, for example, have at least one winding, also referred to as a rotor winding, which is held on the rotor core or is thus supported by the rotor core. In particular, the rotor, particularly in contrast to the wheel carrier, is a magnetically active element by means of which, for example, a magnetic flux is to be guided, which can be generated by the electric machine, for example, during operation of the electric machine, in particular to drive the wheel hub and thus the vehicle wheel.

[0024] Preferably, the electrical machine is a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and most preferably amounts to several hundred volts.

[0025] In a further, particularly advantageous embodiment of the invention, the rotor support section has a recess designed to accommodate the coupling element in the coupled state. In other words, it is preferably provided that, in the coupled state, the coupling element is accommodated in the recess of the rotor support section, thus engaging the recess. As a result, in the coupled state, the coupling element interacts in a form-fitting manner with the rotor support section and, via the rotor support section, in a form-fitting manner with the rotor, whereby the brake pad wear of the wheel hub drive can be kept particularly low, particularly in the axial direction.

[0026] In order to be able to realize a particularly compact design of the wheel hub drive, a further embodiment of the invention provides that the rotor bearing is arranged radially inside the rotor carrier section.

[0027] A further embodiment is characterized in that the vehicle wheel has the aforementioned wheel disc. Furthermore, it is conceivable that the vehicle wheel has the aforementioned rim. The wheel disc and the rim are preferably, in particular permanently, connected to one another in a rotationally fixed manner. In principle, it would be conceivable for the rim and the wheel disc to be separate from one another and, in particular permanently, connected to one another in a rotationally fixed manner, or for the wheel disc and the rim to be integrally formed with one another, i.e. formed from a single piece and thereby, in particular permanently, connected to one another in a rotationally fixed manner. Very particularly, the tire is mounted on the rim and thus supported by the rim.

[0028] In order to achieve a particularly compact design, it has proven particularly advantageous if, with regard to the axial direction of the wheel hub drive, the wheel disc of the vehicle wheel, the rotor bearing, the wheel bearing, and a wheel carrier section of the wheel carrier are arranged one after the other, i.e., consecutively, in the order in which they are named, i.e., one after the other, in the order mentioned. In other words, it is preferably provided that, with regard to the axial direction of the wheel hub drive, the wheel disc, the rotor bearing, the wheel bearing, and the wheel carrier section are arranged one after the other, i.e., consecutively, in the following order: the wheel disc - the rotor bearing - the wheel bearing - the wheel carrier section. Thus, in the axial direction of the wheel hub drive, the rotor bearing is adjacent to the wheel disc, the wheel bearing is adjacent to the rotor bearing, and the wheel carrier section is adjacent to the wheel bearing.It is preferably provided that the first bearing shell, which is in particular formed separately from the wheel carrier, is fastened to the said wheel carrier section and is thereby connected, in particular permanently, in a rotationally fixed manner to the wheel carrier.

[0029] A further embodiment is characterized by a friction brake, also referred to as a braking device, which has a first braking element permanently connected to the wheel hub in a rotationally fixed manner, a second braking element, and a friction region in which the braking elements designed as friction elements can be brought into frictional interaction, in particular direct interaction, in order to thereby brake the wheel hub and thus the vehicle wheel, in particular with regard to rotations occurring about the main axis of rotation and relative to the wheel carrier. Preferably, the second braking element is connected to the wheel carrier at least indirectly, in particular directly, in particular permanently, in a rotationally fixed manner.The feature that the brake elements can be brought into frictional interaction is to be understood as meaning that the brake elements designed as friction elements can be brought into frictional interaction in the friction region in order to thereby brake the wheel hub and thus the vehicle wheel relative to the wheel carrier and in particular relative to the first bearing shell, in particular with regard to the aforementioned rotations of the wheel hub and thus of the vehicle wheel about the main axis of rotation and relative to the wheel carrier and in particular relative to the first bearing shell.In other words, by actuating the friction brake, in particular hydraulically, the braking elements can be brought into such a, in particular direct, interaction that the friction elements rub against one another, in particular directly, whereby the wheel hub and thus the vehicle wheel can be braked with respect to their respective rotation about the main axis of rotation and relative to the wheel carrier. This allows the motor vehicle as a whole to be braked.

[0030] For example, the first braking element is a brake disc. Thus, the friction brake is preferably designed as a disc brake.

[0031] Finally, it has proven particularly advantageous for the realization of a particularly compact design if the friction area of ​​the friction brake is arranged axially between the wheel disc and the wheel bearing.

[0032] The electric machine is designed, for example, as an axial flux machine (AFM), which is also referred to as an axial flux motor. Alternatively, the electric machine can be designed as a radial flux machine. Preferably, the electric machine is designed as an internal rotor. This means, in particular, that the stator is connected to the wheel carrier on its radially outer side. In this case, for example, at least the rotor carrier section and / or at least one further rotor carrier section of the rotor carrier is arranged radially inside the stator, in particular the rotor carrier section that is arranged axially overlapping the stator.Particularly when the electrical machine is designed as an axial flux machine, the axial flux machine, in particular its rotor, is preferably H-shaped, i.e., in an H-construction, so that, for example, the rotor is at least substantially H-shaped or forms an H-shape, with, for example, at least a portion of the stator being arranged in the H-shape. Furthermore, it would be conceivable for the electrical machine to be designed as an external rotor, i.e., as an external rotor machine.

[0033] The aforementioned rotor carrier section is preferably that part of the wheel carrier which is arranged radially overlapping the wheel bearing.

[0034] The rim and the wheel disc can be formed separately from one another and, for example, connected to one another in a rotationally fixed manner, in particular permanently, by welding the rim and the wheel disc together. It would also be conceivable for the rim and the wheel disc to be formed as one piece. For example, the vehicle wheel is connected to the wheel hub in a rotationally fixed manner such that the wheel disc is connected to the wheel hub in a rotationally fixed manner such that the wheel disc is screwed to the wheel hub. For this purpose, the wheel hub has, for example, receiving openings designed as bores, in which screws, also referred to as wheel bolts, can be received or are accommodated, by means of which screws the wheel disc and thus the vehicle wheel are screwed to the wheel hub and thus connected to the wheel hub in a rotationally fixed manner.

[0035] Furthermore, it would be conceivable for the friction brake to be designed as a drum brake.

[0036] 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, which 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.

[0037] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the single figure, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0038] The drawing shows in the only Fig. 1 shows a partial schematic sectional view of a wheel hub drive for a motor vehicle.

[0039] The only Fig. 1 shows a schematic longitudinal sectional view of a wheel hub drive 10, also referred to as a wheel hub drive device, for a motor vehicle, also referred to simply 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 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, i.e., as a first rolling bearing. In the Fig. 1, 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 to the first bearing shell 16. This means that the bearing shell 20 is arranged coaxially to the bearing shell 16 and is rotatable about a main axis of rotation 22 relative to the bearing shell 16 and relative to the wheel carrier 12. The main axis of rotation 22 is also referred to as the wheel axis of rotation. It can be seen that the first bearing shell 16 is a radially outer bearing ring of the wheel bearing 14, which is fixed to the wheel carrier, and the second bearing shell 20 is a radially inner bearing ring of the wheel bearing 14.The bearing shell 20 is arranged radially inside the bearing shell 16.

[0040] The wheel hub drive 10 also has an electric machine 24, which in the Fig. 1 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 here as an internal rotor. The electric machine 24 has a stator 26 and a stator carrier 28, wherein the stator 26 is designed separately from the wheel carrier 12 and is connected, in particular permanently, in a rotationally fixed manner to the wheel carrier 12. For this purpose, the stator 26 is designed separately from the stator carrier 28 and is connected, in particular permanently, in a rotationally fixed manner to the stator carrier 28 which supports the stator 26. The stator carrier 28 is connected, in particular permanently, in a rotationally fixed manner to the wheel carrier 12. For example, the stator carrier 28 is designed separately from the wheel carrier 12 and is connected, in particular permanently, in a rotationally fixed manner to the wheel carrier 12. Furthermore, it would be conceivable for the stator carrier 28 and the wheel carrier 12 to be formed integrally with one another.The electric machine 24 also has a rotor 30, which in this case has rotor elements 32 and 34. The rotor 30 can be driven by means of the stator 26 and is thus rotatable about the main axis of rotation 22 relative to the stator 26 and relative to the wheel carrier 12 and relative to the stator carrier 28. 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 electric machine 24, for example, during operation of the electric machine 24, in particular in order to thereby drive the rotor 30. The electric machine 24 also has a rotor carrier 36, which is formed separately from the rotor 30 and thus the rotor elements 32 and 34 and is, in particular permanently, connected to the rotor 30 in a rotationally fixed manner. The rotor 30 is, for example, a magnetically active element by means of which the magnetic flux is to be or is guided.

[0041] The rotor elements 32 and 34 are spaced apart in the axial direction of the wheel hub drive 10, whose radial direction coincides with the axial direction of the wheel hub drive 10. The axial direction of the wheel hub drive 10 coincides with the main axis of rotation 22, and the radial direction of the wheel hub drive 10 is perpendicular to the main axis of rotation 22 and is illustrated by a double arrow 38. At least a partial region T of the stator 26 is arranged in the axial direction of the wheel hub drive 10 between the rotor elements 32 and 34 in such a way that the rotor element 32, viewed along the main axis of rotation 22 and towards the rotor element 34, is at least partially overlapped, i.e. covered, by the partial region T, and that the rotor element 34, viewed along the main axis of rotation 22 and thus in the axial direction of the wheel hub drive 10 and towards the rotor element 32, is at least partially overlapped, i.e. covered, by the partial region T.By means of the rotor 30, the second bearing shell 20 can be driven and thereby rotated about the main axis of rotation 22 relative to the first bearing shell 16 and relative to the wheel carrier 12.

[0042] The wheel hub drive 10 also has a wheel hub 40, which is mounted on the wheel carrier 12 so as to be rotatable about the main axis of rotation 22 relative to the wheel carrier 12 via the wheel bearing 14 and thus via the bearing shells 16 and 20. The wheel hub 40 is arranged coaxially to the bearing shell 20 and coaxially to the bearing shell 16. In the Fig. 1, the wheel hub 40 and the bearing shell 20 are formed integrally with one another. The wheel hub drive 10 also has a vehicle wheel 42, which is connected in a rotationally fixed manner to the wheel hub 40. The vehicle wheel 42 has a rim 44 with a rim base 46 and a wheel disc 48. In the embodiment shown in Fig. 1, the rim 44 and the wheel disc 48 are formed integrally with one another and are thus permanently connected to one another in a rotationally fixed manner. A Fig. 1, a tire (not shown) can be mounted, which is thus formed separately from the rim 44 and separately from the wheel disc 48 and fastened to the rim 44. The wheel disc 48 has a particularly central fastening region 50 which has a plurality of through-openings 52, for example formed as bores. Each through-opening 52 is penetrated by a respective wheel bolt 54. By means of the wheel bolts 54, the wheel disc 48 and thus the vehicle wheel 42 are screwed to the wheel hub 40 and thus connected to the wheel hub 40 in a rotationally fixed manner. The vehicle wheel 42 is thus mounted on the wheel carrier 12 via the wheel hub 40 and the wheel bearing 14 so as to be rotatable about the main axis of rotation 22 relative to the wheel carrier 12. It can be seen in particular that the respective wheel bolt 54 is screwed into a respective corresponding screw opening 56 of the wheel hub 40, which is designed, for example, as a through opening.

[0043] The rotor 30 is rotatably mounted at least indirectly on the wheel carrier 12 via a rotor bearing 58, which is provided in addition to the wheel bearing 14 and is designed as a second rolling bearing. In the present case, the rotor 30 is rotatably mounted on the wheel carrier 12 via the rotor bearing 58, mediated by the wheel hub 40 and the wheel bearing 14.

[0044] The wheel bearing 14 has first rolling elements 60, which form a first row of rolling elements. Furthermore, the wheel bearing 14 has second rolling elements 62, which form a second row of rolling elements, wherein the first row of rolling elements and the second row of rolling elements are arranged consecutively in the axial direction of the wheel hub drive 10. The bearing shell 16 forms a first raceway L1 for the rolling elements 60 and 62, and the bearing shell 20 forms a second raceway L2 for the rolling elements 60 and 62. If the bearing shell 20 rotates about the main axis of rotation 22 relative to the bearing shell 16, the rolling elements 60 and 62 roll directly on the raceways L1 and L2.

[0045] The rotor bearing 58, designed as a second rolling bearing, has third rolling elements 64 and fourth rolling elements 66. The rotor bearing 58 has, for example, a third bearing shell 68, which in this case is connected, in particular permanently, in a rotationally fixed manner to the bearing shell 20 and the wheel hub 40. In this case, the bearing shell 68 is formed integrally with the bearing shell 20 and the wheel hub 40, so that, for example, the wheel hub 40 or the bearing shell 20 forms the bearing shell 68. The rotor bearing 58 has a fourth bearing shell 70, which is connected, in particular permanently, in a rotationally fixed manner to the rotor carrier 36. In principle, it would be conceivable for the bearing shell 70 and the rotor carrier 36 to be formed integrally with one another, so that, so to speak, the rotor carrier 36 forms the bearing shell 70. In the Fig. 1, however, the fourth bearing shell 70 is formed separately from the rotor carrier 36 and, in particular, is permanently connected to the rotor carrier 36 in a rotationally fixed manner. The bearing shell 68 forms a third raceway L3 for the rolling elements 64 and 66, and the bearing shell 70 forms a fourth raceway L4 for the rolling elements 64 and 66. If the rotor 30 and thus the rotor carrier 36, which is permanently connected to the rotor 30 in a rotationally fixed manner, and the bearing shell 70 rotate about the main axis of rotation 22 relative to the bearing shell 68 and thus relative to the wheel hub 40 and the bearing shell 20, the rolling elements 64 and 66 each roll directly on the raceways L3 and L4. It can be seen that the electric machine 24, thus the rotor 30, the wheel hub 40, the bearing shells 16 and 20 and thus the wheel bearing 14 as well as the bearing shells 68 and 70 and thus the rotor bearing 58 are all arranged coaxially to one another.

[0046] The wheel hub drive 10 further comprises a coupling device K, which can be switched between a coupled state and a decoupling state. In the coupled state, the rotor 30 is positively connected to the wheel hub 40 in a rotationally fixed manner by means of the coupling device K, such that the coupling device K is a positively locking coupling device K. In the decoupling state, the rotor 30 is rotatable about the main axis of rotation 22 relative to the wheel hub 40, such that in the decoupling state the coupling device K releases the rotor 30 for rotation about the main axis of rotation 22 and relative to the wheel hub 40. In particular, in the decoupling state, no torque can be transmitted between the wheel hub 40 and the rotor 30, and thus between the vehicle wheel 42 and the rotor 30, via the coupling device K, such that, for example, when the motor vehicle is in its overrun mode, the rotating vehicle wheel 42 does not drag the rotor 30.This enables particularly efficient operation.

[0047] In order to be able to realize a particularly compact and thus space-saving design of the wheel hub drive 10, the coupling device K has a coupling element 72 extending in the radial direction of the wheel hub drive 10, which, as illustrated by an arrow 74, is displaceable in the radial direction of the wheel hub drive 10 relative to the wheel hub 40 and relative to the rotor 30 and relative to the rotor carrier 36, specifically between at least one in Fig. 1, which brings about the decoupling state, and at least one coupling position which brings about the coupling state.

[0048] The coupling element 72 is permanently connected to the wheel hub 40 in a rotationally fixed manner, at least with respect to the main rotation axis 22, about which the wheel hub 40 is rotatable relative to the wheel carrier 12. For example, the coupling element 72 is designed as a pin, which is also referred to as a stud. Thus, for example, the coupling element 72 is cylindrical on its outer circumference, at least in a longitudinal region of the coupling element 72.

[0049] It can be seen that the coupling element 72 is arranged axially overlapping the rotor bearing 58. At least in the coupling position and, in this case, also in the decoupling position, the coupling element 72 penetrates the rotor bearing 58. It can be seen that the rolling elements 64 form a third row of rolling elements and the rolling elements 66 form a fourth row of rolling elements, wherein the third row of rolling elements and the fourth row of rolling elements are arranged consecutively in the axial direction of the wheel hub drive 10. The feature that the coupling element 72 penetrates the rotor bearing 58 at least in the coupling position and, in this case, also in the decoupling position, is to be understood in particular that the coupling element 72 is arranged between the third row of rolling elements and the fourth row of rolling elements in the axial direction of the wheel hub drive 10, at least in the coupling position and, in this case, in the decoupling position.

[0050] It can be seen that the bearing shell 70 has a through-opening 76 and the rotor carrier 36 has a recess 78, which in this case is designed like a blind hole. In the uncoupling position, the coupling element 72 is arranged both outside the through-opening 76 and outside the recess 78, whereby the rotor 30 is decoupled from the wheel hub 40 and can rotate about the main axis of rotation 22 relative to the wheel hub 40. Both in the coupling position and in the uncoupling position, the coupling element 72 is arranged in a corresponding receptacle 77 of the wheel hub 40, for example designed as a through-opening, in particular such that the coupling element 72 completely penetrates the receptacle 77 in the radial direction of the wheel hub drive 10, both in the uncoupling position and in the coupling position.In the coupling position, the coupling element 72 completely penetrates the through-opening 76, and in the coupling position, the coupling element 72 engages in the recess 78 of the rotor carrier 36, so that the coupling element 72 is arranged in the recess 78 in the coupling position. As a result, in the coupling position of the coupling element 72, the wheel hub 40 and the rotor carrier 36, and via the latter, the rotor 30, are positively connected to one another in a rotationally fixed manner by means of the coupling element 72.

[0051] In order to realize a particularly compact design, it is further provided that the rotor bearing 58 is arranged radially within a rotor carrier section RA of the rotor carrier 36, wherein the recess 78 is formed in the rotor carrier section RA. With regard to the axial direction of the wheel hub drive 10, the wheel disc 48, the rotor bearing 58, the wheel bearing 14 and a wheel carrier section A of the wheel carrier 12 are arranged one after the other in the following order: the wheel disc 48 - the rotor bearing 58 - the wheel bearing 14 - the wheel carrier section A. The first bearing shell 16 of the wheel bearing 14, which is formed separately from the wheel carrier 12, is fastened to the wheel carrier section A and is thereby connected to the wheel carrier section A in a rotationally fixed manner.

[0052] The coupling element 72 can be moved back and forth between the coupling position and the decoupling position in the radial direction of the wheel hub drive 10 in the following manner: The coupling device K has an actuating element 80, which is, for example, a releaser or is referred to as a releaser. As illustrated by a double arrow 82, the actuating element 80 can be displaced, i.e., pushed back and forth, along the main axis of rotation 22 and thus in the axial direction of the wheel hub drive 10 relative to the coupling element 72. For this purpose, the coupling device K has, for example, an actuator 84, by means of which the actuating element 80 can be pushed, for example, toward the coupling element 72 and, for example, also away from the coupling element 72, specifically in the axial direction of the wheel hub drive 10.The coupling element 72 has a first actuating surface, and the actuating element 80 has a second actuating surface corresponding to the first actuating surface. The actuating surfaces extend in a respective plane, wherein the respective plane extends obliquely to the radial direction and obliquely to the axial direction of the wheel hub drive 10. The planes coincide, for example, or the planes run parallel to one another. If the actuating element 80 is moved in the axial direction of the wheel hub drive 10 toward the coupling element 72, that is, in this case, pushed, thus moved translationally, the actuating surfaces slide, in particular directly, against one another.As a result, the translational movement of the actuating element 80 running in the axial direction of the wheel hub drive 10 is converted into a displacement running in the radial direction of the wheel hub drive 10, and thus a translational movement of the coupling element 72, such that by pushing the actuating element 80 in the axial direction of the wheel hub drive 10 in the direction of the coupling element 72, the coupling element 72 is pushed from the uncoupling position into the coupling position.

[0053] The actuating element 80 is assigned a return element 86 of the coupling device K. In the Fig. 1, the return element 86 is a spring, which in this case is designed as a solid body and thus as a mechanical spring. By moving the coupling element 72 from the uncoupling position into the coupling position, the return element 86, i.e. in this case the spring, is or becomes tensioned, whereby the return element 86 provides a return force, which in this case is designed as a spring force. By means of the return force, the coupling element 72 can be moved in the radial direction back from the coupling position into the uncoupling position. In this case, for example, the actuating surfaces slide (again) against one another, whereby, for example, the actuating element 80 is moved away from the coupling element 72 in the axial direction of the wheel hub drive 10 or is displaced in a direction pointing away from the coupling element 72.

[0054] The actuator 84 is, for example, an electric actuator, thus an electrically operable actuator. For example, the actuator 84 can be an electric servomotor, which can move the actuating element 80 axially and translationally, for example via a worm or a worm gear, in particular back and forth, in particular in the direction of the coupling element 72 and, for example, away from the coupling element 72. The return element 86 can, for example, move the coupling element 72 from the coupling position to the decoupling position when or by virtue of the actuator 84 moving the actuating element 80 in the axial direction of the wheel hub drive 10 away from the coupling element 72 or in the aforementioned direction. This allows the spring to be relaxed, whereby the spring can move the coupling element 72 from the coupling position to the decoupling position.

[0055] Preferably, a seal, e.g., formed as an O-ring and made of rubber, is provided for the coupling element 72, by means of which, for example, the coupling element 72 is sealed against the wheel hub 40, and the seal is arranged, for example, in the receptacle 77. For example, the coupling element 72 is lubricated by means of a lubricant, in particular by means of a liquid lubricant, wherein, for example, the seal can prevent the lubricant from flowing excessively away from the coupling element 72.

[0056] The wheel hub drive 10 further comprises a braking device designed as a friction brake 87, which comprises a first braking element 88 permanently connected in a rotationally fixed manner to the wheel hub 40 and a second braking element 90, in particular permanently connected in a rotationally fixed manner to the wheel carrier 12. In the Fig.In the embodiment shown in Figure 1, the friction brake 87 is designed as a disc brake, so that the braking element 88 is designed as a brake disc. The friction brake 87 has a friction region B in which the braking elements 88 and 90 can be brought into frictional interaction, in particular direct frictional interaction, in order to thereby brake the vehicle wheel 42. It can be seen that the friction region B is arranged axially between the wheel disc 48 and the wheel bearing 16.

[0057] The wheel hub drive 10 further comprises a bearing 92, embodied, for example, as a plain bearing, via which the actuating element 80 is displaceably mounted on the wheel hub 40. For this purpose, the bearing 92 comprises, for example, a first bearing half connected to the wheel hub 40, which is connected, for example, to the wheel hub 40 in such a way that relative movements between the wheel hub 40 and the first bearing half are prevented. Furthermore, the bearing 92 comprises, for example, a second bearing half connected to the actuating element 80, which is connected, for example, to the actuating element 80 in such a way that relative movements between the actuating element 80 and the second bearing half are prevented. The bearing halves of the bearing 92 are displaceable relative to one another, for example, along the main axis of rotation 22. 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 Main axis of rotation 24 electric machine 26 Stator 28 stator carriers 30 rotors 32 Rotor element 34 Rotor element 36 rotor arms 38 double arrow 40 Wheel hub 42 vehicle wheel 44 rim 46 rim base 48 wheel disc 50 mounting area 52 passage opening 54 wheel bolt 56 screw opening 58 rotor bearings 60 first rolling element 62 second rolling element 64 third rolling element 66 fourth rolling element 68 third bearing shell 70 fourth bearing shell 72 coupling element 74 Double arrow 76 passage opening 77 recording 78 recess 80 Actuator 82 Double arrow 84 Actuator 86 Reset element 87 Friction brake 88 first brake element 90 second brake element 92 warehouses A wheel carrier section B braking area L1 first career L2 second career L3 third career L4 fourth career K coupling device RA rotor carrier section 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] DE 10 2022 000 026 A1

[0002]

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (12), a wheel hub (40) rotatably mounted on the wheel carrier (12) via a wheel bearing (14), a vehicle wheel (42) which is connected to the wheel hub (40) in a rotationally fixed manner, an electric machine (24) which has a stator (26) connected to the wheel carrier (12) in a rotationally fixed manner and a rotor (30) which is drivable by means of the stator (26) and is thereby rotatable relative to the stator (26), which rotor is rotatably mounted on the wheel carrier (12) via a rotor bearing (58) provided in addition to the wheel bearing (14), and a positive coupling device (K) which can be switched between a coupling state in which the rotor (30) is connected to the wheel hub (40) in a rotationally fixed manner by means of the coupling device (K), and a decoupling state in which the rotor (30) is rotatably connected to the Wheel hub (40) is rotatable, characterized bythat the coupling device (K) has a coupling element (72) extending in a radial direction (38) of the wheel hub drive (10) and arranged so as to be displaceable along the radial direction (38) of the wheel hub drive (10) relative to the wheel hub (40) and relative to the rotor (30). [2] Wheel hub drive (10) according to claim 1, characterized by that the coupling element (72) is permanently connected to the wheel hub (40) in a rotationally fixed manner at least with respect to an axis of rotation (22) about which the wheel hub (40) is rotatable relative to the wheel carrier (12). [3] Wheel hub drive (10) according to claim 1 or 2, characterized by that the coupling element (72) is arranged axially overlapping the rotor bearing (58). [4] Wheel hub drive (10) according to one of the preceding claims, characterized by that the coupling element (72) radially penetrates the rotor bearing (58). [5] Wheel hub drive (10) according to one of the preceding claims, characterized bythat a rotor carrier section (RA) of a rotor carrier (36) carrying the rotor (30) is arranged axially overlapping the rotor bearing (58). [6] Wheel hub drive (10) according to claim 5, characterized by that the rotor carrier section (RA) has a recess (78) which is designed to receive the coupling element (72) in the coupling state. [7] Wheel hub drive (10) according to claim 5 or 6, characterized by that the rotor bearing (58) is arranged radially inside the rotor carrier section (RA). [8] Wheel hub drive (10) according to one of the preceding claims, characterized by that the vehicle wheel (42) has a wheel disc (48). [9] Wheel hub drive (10) according to claim 8, characterized bythat with regard to the axial direction of the wheel hub drive (10), the wheel disc (48) of the vehicle wheel (42), the rotor bearing (58), the wheel bearing (14) and a wheel carrier section (A) of the wheel carrier (12) are arranged one after the other in the following order: the wheel disc (48) - the rotor bearing (58) - the wheel bearing (14) - the wheel carrier section (A). [10] Wheel hub drive (10) according to one of the preceding claims, characterized by a friction brake (87) which has a first brake element (88) permanently connected to the wheel hub (40) in a rotationally fixed manner, a second brake element (90) and a friction region (B) in which the brake elements (88, 90) can be brought into frictional interaction in order to thereby brake the vehicle wheel (42). [11] Wheel hub drive (10) according to claims 9 and 10 or according to claims 8 and 10, characterized by that the friction area (B) of the friction brake (87) is arranged axially between the wheel disc (48) and the wheel bearing (14). [12] Motor vehicle, with at least one wheel hub drive (10) according to one of the preceding claims.

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