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

Abstract

The present invention relates to a wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (18), a wheel bearing (20) which has a first bearing shell (22) rotationally fixed to the wheel carrier (18) and a second bearing shell (24) rotatably arranged relative to the first bearing shell (22), a vehicle wheel (12) which has a wheel disc (14) rotationally fixed to the second bearing shell (14) and a rim (16) rotationally fixed to the wheel disc (14), an electric machine (50) which has a rotor (52) rotationally fixed to or connectable to the second bearing shell (24) and a stator (54), and an elastic element (66) which is designed to elastically connect the stator (54) to the wheel carrier (18). The provision includes a first support bearing (68) which has a third bearing shell (70) connected to the second bearing shell (24) in a rotationally fixed manner and a fourth bearing shell (72) connected to the stator (54) in a rotationally fixed manner.

Description

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

[0002] DE 10 2007 014 304 A1 discloses a hybrid vehicle powertrain as known, comprising an internal combustion engine having an engine block and a crankshaft, and an electric machine having a stator connected to the engine block and a rotor rotatably mounted on the stator, which can be connected to the crankshaft via an adjustable coupling.

[0003] Wheel hub drives for motor vehicles in which an electric machine is arranged within a rim of a wheel are known from DE 10 2023 001 269 A1, DE 10 2023 001 258 A1, JP 2020 - 128 134 A and JP 2012 - 232 616 A.

[0004] The object of the present invention is to create a wheel hub drive for a motor vehicle and a motor vehicle with at least one such wheel hub drive, so that a particularly advantageous operation can be realized.

[0005] This problem is solved by a wheel hub drive with the features of claim 1 and by a motor vehicle with the features of claim 9. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] 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 assembly, for a motor vehicle, which is preferably a car, and in particular 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. 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, the motor vehicle, in its fully manufactured state, has at least or exactly two axles, also referred to simply as axles, arranged one behind the other and thus consecutively in the longitudinal direction of the motor vehicle.Each axle of the motor vehicle has at least or exactly two wheels, also simply referred to as wheels, with the wheels of each axle being arranged on opposite sides of the vehicle in the transverse direction. The wheels of the motor vehicle are ground contact elements by which the vehicle can be supported or is supported downwards against the ground in the vertical direction. When the motor vehicle, whose interior, also referred to as the passenger compartment, is formed, for example, by a body structure, particularly a self-supporting body, is driven along the ground while the vehicle is supported downwards in the vertical direction by the ground contact elements, the ground contact elements roll along the ground, particularly directly.The wheel hub drive is also referred to as the first wheel hub drive. When the wheel hub drive is mentioned before and below, it refers, unless otherwise specified, to the first wheel hub drive. For example, the wheel hub drive specifically includes the first of the vehicle wheels on one of the vehicle axles. When the vehicle wheel is mentioned before and below, it refers, unless otherwise specified, to the first vehicle wheel. Thus, the first vehicle wheel can be driven, particularly electrically, by means of the first wheel hub drive.For example, in its fully manufactured state, the motor vehicle has a second wheel hub drive in addition to the first, by means of which, in particular, a second of the vehicle's wheels can be driven, especially purely electrically, and it is conceivable that the second wheel hub drive comprises the second vehicle wheel. Preferably, the first and second vehicle wheels are the same axle. The preceding and following descriptions of the first wheel hub drive and the first vehicle wheel can readily be applied to the second wheel hub drive and the second vehicle wheel, and vice versa.

[0007] The wheel hub drive comprises a wheel carrier and a wheel bearing assembly, which includes a first bearing shell, or a first bearing shell assembly, and a second bearing shell, or second bearing shell assembly, rotatably arranged relative to the first bearing shell and rotatably about a wheel axis of rotation. The feature that the second bearing shell is rotatably arranged relative to the first bearing shell and rotatably about the aforementioned wheel axis of rotation means that the second bearing shell is rotatable about the wheel axis of rotation relative to the first bearing shell. The second bearing shell is arranged coaxially with the first bearing shell.

[0008] The first bearing race is permanently connected to the wheel carrier in a rotationally fixed manner, so that the second bearing race is rotatable about the wheel's axis of rotation relative to the wheel carrier and relative to the first bearing race. Furthermore, the second bearing race is arranged coaxially with the first bearing race, so that the first and second bearing races are coaxial with respect to the axis of rotation. The vehicle wheel is rotatably mounted to the wheel carrier via the wheel bearing about the wheel's axis of rotation relative to the wheel carrier, which is also simply referred to as the axis of rotation. For example, the vehicle wheel is permanently connected to the second bearing race in a rotationally fixed manner, so that the second vehicle wheel, together with the second bearing race, is rotatable about the wheel's axis of rotation relative to the wheel carrier and also relative to the first bearing race.

[0009] The second bearing shell is arranged radially inside the first bearing shell. Conversely, the first bearing shell is arranged radially outside the second bearing shell.

[0010] The term "bearing shell" is particularly advantageous to refer to a bearing ring or bearing ring assembly of a plain bearing or a plain bearing assembly. A plain bearing assembly is understood to be an assembly with several individual plain bearings, wherein the individual plain bearings are arranged coaxially to one another, and wherein the individual plain bearings may advantageously, but not necessarily, have the same diameter. In the case of a plain bearing assembly, a bearing ring assembly means an assembly with several bearing rings distributed across several individual plain bearings, in particular a bearing ring assembly of radially inner sliding rings or a bearing ring assembly of radially outer sliding rings.When, in the case of a sliding bearing device with sliding bearings of different diameters, it is stated that an element which does not belong to the sliding bearing device is arranged radially outside the bearing ring device (as a special case of the bearing shell), it is meant that this element is arranged radially outside the bearing ring of the bearing device which has the largest diameter among the bearing rings of the bearing ring device.

[0011] When, in the case of a sliding bearing device with sliding bearing devices of different diameters, it is stated that a bearing shell of the sliding bearing device, i.e. a sliding ring device, is arranged radially outside another bearing shell of the sliding bearing device, i.e. another sliding ring device, it is meant that the sliding rings of the bearing shell are each arranged radially outside the sliding rings of the other bearing shell that are assigned to them.

[0012] The vehicle wheel has a wheel disc which is permanently and rotationally fixed to the second bearing race. The vehicle wheel also has a rim which is permanently and rotationally fixed to the wheel disc. In principle, it would be conceivable for the rim and the wheel disc to be designed separately and permanently and rotationally fixed to each other. Furthermore, it would be possible for the wheel disc and the rim to be formed as a single unit, that is, from a single piece, and thereby permanently and rotationally fixed to each other.Within the scope of the present disclosure, the feature that two elements, such as the rim and the wheel disc, are formed in one piece, i.e., are formed from a single piece, is to be understood as meaning that these elements are not formed separately from one another and connected to each other, but rather that these elements are formed in one piece, that is, from a single piece and thus constituted by a single-piece, i.e., integrally manufactured, body formed as a monoblock. In particular, the rim is a radially outer, especially outermost, part of the vehicle wheel, which is also simply referred to as a wheel. For example, a tire, which is preferably made of rubber and formed separately from the vehicle wheel, the rim, and the wheel disc, is attached to the rim, so that the tire is, so to speak, mounted on the rim.In particular, when the vehicle wheel rolls on the aforementioned ground, the tire rolls, especially directly, on the ground.

[0013] The wheel hub drive also includes an electric machine comprising a 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. Preferably, the rotor is arranged coaxially with the wheel bearing and thus coaxially with the bearing shells, so that the machine axis of rotation preferably coincides with the wheel axis of rotation. The wheel axis of rotation is also referred to as the main axis of rotation of the wheel hub drive, the axial direction of which coincides with the wheel axis of rotation. In particular, by driving the rotor, the vehicle wheel can be driven, especially purely electrically, and is thus rotatable about the wheel axis of rotation relative to the wheel carrier and relative to the first bearing shell.Thus, for example, the wheel hub drive, whose radial direction is perpendicular to the axial direction of the wheel hub drive and therefore perpendicular to the wheel's axis of rotation, has the main axis of rotation with which the wheel's axis of rotation and preferably also the machine's axis of rotation coincide. When the axial direction is mentioned below, unless otherwise specified, this refers to the axial direction of the wheel hub drive, whose axial direction coincides with the main axis of rotation. When the radial direction is mentioned below, unless otherwise specified, this refers to the radial direction of the wheel hub drive, whose radial direction is perpendicular to the axial direction and therefore perpendicular to the machine's axis of rotation. In particular, it is provided that the rotor is arranged axially overlapping the rim. For example, the stator is, in particular, permanently and rotationally fixed to the wheel carrier.The rotor is or can be connected to the second bearing shell in a rotationally fixed manner. It is conceivable that the rotor is permanently and rotationally fixed to the second bearing shell. Furthermore, it is conceivable that the rotor can be connected to the second bearing shell in a rotationally fixed manner. For example, the rotor is designed separately from the second bearing shell and is or can be connected to the second bearing shell in a rotationally fixed manner, so that, for example, the rotor, which is designed separately from the second bearing shell, is permanently and rotationally fixed to the second bearing shell, or the rotor, which is designed separately from the second bearing shell, can be connected to the second bearing shell in a rotationally fixed manner.

[0014] The wheel hub drive features an elastic element designed to elastically connect the stator to the wheel carrier. In other words, the stator is connected to the wheel carrier via the elastic element and thus, in particular, permanently and rotationally fixed to the wheel carrier. For example, the elastic element is designed separately from the wheel carrier and, in particular, permanently and rotationally fixed to the wheel carrier. Alternatively or additionally, the elastic element is designed separately from the stator and, in particular, permanently and rotationally fixed to the stator. The characteristic that the stator is elastically connected to the wheel carrier via the elastic element means that the stator has limited movement relative to the wheel carrier under elastic deformation of the elastic element.In other words, the elastic element is elastically deformable and thus allows relative movements between the stator and the wheel carrier. These relative movements cause the elastic element to deform. The characteristic that the elastic element is elastic means that it is elastically deformable. This means that the elastic element, particularly with regard to its shape and / or the material from which it is made, is specifically designed to be elastically deformable. In other words, it is specifically designed to allow relative movements between the stator and the wheel carrier through elastic deformation.

[0015] Preferably, the wheel bearing is also referred to as a first rolling bearing, which also has first rolling bearings, via which the second bearing shell is rotatably mounted on the first bearing shell about the wheel's axis of rotation relative to the first bearing shell. This allows for particularly low-friction and therefore low-loss operation.

[0016] To achieve a particularly advantageous operation of the wheel hub drive, the invention provides a first support bearing, in particular in addition to the wheel bearing, which has a third bearing shell, in particular permanently and rotationally fixed to the second bearing shell, and a fourth bearing shell, in particular permanently and rotationally fixed to the stator, wherein the third bearing shell is arranged radially inside the fourth bearing shell. Conversely, the fourth bearing shell is arranged radially outside the third bearing shell. Furthermore, the third bearing shell is arranged radially outside the first bearing shell. Conversely, the first bearing shell is arranged radially inside the third bearing shell.The support bearing allows, for example, movements of the rotor relative to the wheel carrier, in particular tilting movements, to be transmitted to the stator, whereby, because the stator is connected to the wheel carrier via the elastic element and because the elastic element allows relative movements between the stator and the wheel carrier under elastic deformation of the elastic element, the stator also carries out the aforementioned movements, in particular tilting movements, of the rotor relative to the wheel carrier.This allows, for example, undesirable, excessive changes in the size of a radial air gap, i.e., an air gap arranged in the radial direction between the stator and the rotor. As a result, the air gap can be advantageously small even in a rest state of the wheel hub drive, in which there are no relative movements between the stator and the rotor, between the rotor and the wheel carrier, and between the stator and the wheel carrier. This is particularly true with regard to the radial width of the air gap. This enables a particularly efficient and thus highly effective operation of the electric machine and, consequently, the wheel hub drive. Specifically, the aforementioned tilting movements occur around a tilting axis that is perpendicular to an imaginary plane in which the wheel's axis of rotation lies.The rotor and stator can advantageously perform these tilting movements around the tilting axis relative to the wheel carrier together, so that despite these tilting movements, the air gap remains essentially constant in width, or rather, undesirable changes in the air gap's size are avoided. This allows the air gap to be advantageously small, i.e., narrow, even in the rest state of the wheel hub drive, especially compared to conventional solutions, thus enabling particularly efficient operation of the wheel hub drive.

[0017] Preferably, the electric 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 several hundred volts.

[0018] Within the scope of this disclosure, the feature "radially overlapping" is to be understood as follows: Two elements of the wheel hub drive, which are at least substantially rotationally symmetrical, are arranged in a radially overlapping manner, particularly with respect to a common axis extending, for example, in the radial direction, and / or in the radial direction, if they are each arranged at least partially within a region of identical radial coordinates, in particular identical angular coordinates. The term "radial" refers to the radial direction. In other words, the term "radial" means the radial direction.

[0019] The feature "axially overlapping" means the following: Two elements are arranged axially overlapping with respect to a common axis, particularly one extending in the axial direction, such as the wheel axis of rotation, and / or in the axial direction, particularly with respect to each other, if they are each arranged at least partially within a region of identical axial coordinates. Within the scope of this disclosure, the term "axial" refers to the axial direction. In other words, the term "axial" refers to the axial direction of the wheel hub drive. Put another way, "axial" refers to the axial direction, and "radial" refers to the radial direction.

[0020] Within the scope of the present disclosure, the feature that a first component is arranged radially within a second component means that the first component is arranged in a region of smaller radii than the second component, particularly with respect to the wheel axis of rotation, such that the aforementioned radii are perpendicular to the wheel axis of rotation and, in particular, begin at the wheel axis of rotation. Furthermore, the feature that a first component is arranged axially within a second component means that, in the installed position of the wheel hub drive, which assumes its installed position in the fully manufactured state of the motor vehicle comprising the wheel hub drive, and particularly with respect to a straight-ahead position of the vehicle wheel, that is to say, in particular when the steering of the motor vehicle is set to effect straight-ahead driving, the first componentwhich is arranged axially within the second component, is located on one side of the second component towards a center of the motor vehicle also referred to as the vehicle center, thus the first component is located on a side of the second component pointing towards the center of the motor vehicle, so that the first component, in particular when viewed in the transverse direction of the motor vehicle, is located further inwards, i.e. closer to the center of the motor vehicle than the second component.

[0021] Within the scope of the present disclosure, the feature that two components, such as the second bearing shell and the third bearing shell, are rotationally fixed to one another is understood to mean that the rotationally fixed components are arranged coaxially and, in particular when the components are driven, rotate together or simultaneously about a common axis of rotation of the components, such as the wheel axis of rotation, at the same angular velocity, especially relative to a reference element such as the wheel carrier. In other words, two components are rotationally fixed to one another if they are arranged coaxially, especially with respect to their axis of rotation and / or with respect to a rotational axis of symmetry, and if they are connected to one another in such a way that they always rotate at the same angular velocity.An element is non-rotatably connected to a housing or wheel carrier if it cannot be rotated opposite, that is, relative to the housing or wheel carrier.

[0022] The characteristic that two components are connected or coupled in a torque-transmitting manner means that the components are coupled or connected in such a way that torques can be transmitted between them. If the components are connected or coupled in a rotationally fixed manner, they are also connected or coupled in a torque-transmitting manner. Two components connected in a torque-transmitting manner can thus be connected in a rotationally fixed manner. Furthermore, it is conceivable that two components connected in a torque-transmitting manner are connected via an intermediate transmission unit, such that torques can be transmitted between the components via this transmission unit while the components are connected in a torque-transmitting manner, although the components may be rotatable relative to each other.The characteristic that two components, such as the first bearing shell and the wheel carrier, are permanently connected or coupled to each other in a torque-transmitting manner means that there is no switching element that can be toggled between a coupling state in which the components are connected or coupled 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, meaning they are connected or coupled to each other in such a way that torque can be transmitted between them. Thus, for example, one component can be driven by the other, and vice versa.

[0023] In particular, the feature that two components, such as the first bearing shell and the wheel carrier, are permanently connected or coupled to each other in a rotationally fixed manner means that a switching element is not provided which can be switched between a coupling state in which the components are rotationally fixed to each other and a decoupling state in which the components are decoupled from each other and rotatable relative to each other, so that no torques can be transmitted between the components via the switching element. Rather, the components are always, i.e., permanently, rotationally fixed to each other. Furthermore, the featureThe fact that two components, such as the second bearing shell and the rotor, can be connected or coupled to each other 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 each other in a rotationally fixed manner by means of the switching element. In the decoupling state, the components are decoupled from each other, so that in the decoupling state the components can rotate relative to each other about the component's axis of rotation, i.e., for example, about the wheel's axis of rotation. The same applies to the feature that two components can be connected or coupled to each other in a torque-transmitting manner.Thus, for example, the characteristic that two components can be connected or coupled to each other in a torque-transmitting manner means 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 enabled state. In the connected state, the components are coupled or connected to each other by means of the switching element in a torque-transmitting manner, so that torques can be transmitted between the components, in particular via the switching element. In the enabled state, the components are decoupled from each other, so that no torque can be transmitted between the components via the switching element in the enabled state.

[0024] In particular, the first bearing race is a radially outer, especially the outermost, and wheel carrier-fixed, that is, especially permanently and rotationally fixed, first bearing ring of the wheel bearing, wherein, for example, the second bearing race is a radially inner, second bearing ring of the wheel bearing. For example, the wheel disc and thus the vehicle wheel are connected to the second bearing race in such a way, especially permanently and rotationally fixed, that the wheel disc is screwed to the second bearing race. Thus, for example, screw elements, especially designed as screws, are provided, designed separately from the second bearing race and separately from the vehicle wheel and thus separately from the wheel disc, by means of which the wheel disc and thus the vehicle wheel are screwed to the second bearing race and thereby permanently and rotationally fixed to the second bearing race.

[0025] By arranging the third bearing shell radially inside the fourth bearing shell and radially outside the first bearing shell, a particularly space-saving design can be achieved, and the aforementioned movements, especially tilting movements, of the rotor can be transferred to the stator particularly advantageously, so that the rotor and the stator can subsequently perform the movements, especially tilting movements, relative to the wheel carrier together.

[0026] In an advantageous embodiment of the invention, the elastic element is arranged radially within the stator. This allows the stator to perform the movements of the rotor relative to the wheel carrier, particularly tilting movements, with the elastic and therefore non-destructive deformation of the elastic element, thus enabling a particularly advantageous operation of the electric machine and therefore of the wheel hub drive.

[0027] Preferably, the electric machine is designed as an external rotor machine. Thus, the stator is connected to the wheel carrier, for example, on its radially inner side, and is thereby permanently and rotationally fixed to the wheel carrier. Furthermore, it is provided, for example, that at least one rotor carrier section is arranged radially outside the stator. The rotor carrier section is a section of a rotor carrier of the rotor. More specifically, the rotor carrier section is a cylindrical section of the rotor carrier, the cylindrical section of which is cylindrical on its outer and / or inner circumference. Most preferably, the electric machine is designed as an axial flux machine, which is also referred to as an axial flux motor (AFM).

[0028] In particular, the rotor, especially in contrast to the rotor carrier, is a magnetically active element by means of which, for example, a magnetic flux is to be guided. This flux can be generated by the electric machine during operation, in particular to drive the rotor and thus the wheel disc or the vehicle wheel. More specifically, the rotor is designed separately from the rotor carrier and is, in particular, permanently and rotationally fixed to the rotor carrier. In particular, the rotor carrier is, in particular, permanently and rotationally fixed to the wheel disc.

[0029] In a particularly advantageous embodiment of the invention, the elastic element is arranged radially within the fourth bearing shell. This ensures, in a particularly space-saving manner, that the stator and rotor jointly execute the movements relative to the wheel carrier, especially tilting movements. This prevents undesirable, excessive changes in the air gap, allowing the air gap to be made particularly narrow, especially in the rest state. Thus, particularly efficient operation is ensured.

[0030] Another embodiment is characterized in that the elastic element is arranged axially on the side of the first support bearing facing away from the wheel disc. This allows the movements of the rotor to be advantageously transferred to the stator, so that the stator can move advantageously with the rotor under elastic deformation of the elastic element. Consequently, the air gap relative to the rest state of the wheel hub drive can be advantageously designed to be small, thus enabling efficient operation.

[0031] In order to achieve a particularly advantageous operation of the wheel hub drive, a further embodiment of the invention provides that the aforementioned cylindrical section of the rotor carrier is arranged radially outside the stator. Thus, the electric machine is preferably designed as an external rotor machine, i.e., as an external rotor.

[0032] In order to transfer the aforementioned movements of the rotor to the stator particularly advantageously, a further embodiment of the invention provides a second support bearing, in particular in addition to the first support bearing and especially in addition to the wheel bearing, which has a fifth bearing shell, in particular permanently, rotationally fixed to the second bearing shell and a sixth bearing shell, in particular permanently, rotationally fixed to the stator, wherein the fifth bearing shell is arranged radially outside the sixth bearing shell.

[0033] In order to achieve a particularly advantageous operation, it has proven especially advantageous if the second support bearing is arranged axially, that is, in the axial direction and thus along the wheel rotation axis, on a side of the elastic element facing away from the wheel disc.

[0034] Finally, it has proven particularly advantageous for achieving a highly efficient operation if the rim is designed separately from the wheel disc, wherein a first retaining ring, particularly permanently and rotationally fixed to the rim, and a second retaining ring, particularly permanently and rotationally fixed to the wheel disc, are designed to connect the wheel disc and the rim to each other, particularly permanently and rotationally fixed. For example, the first retaining ring is formed integrally with the rim and is thereby permanently and rotationally fixed to the rim. Alternatively or additionally, the second retaining ring is formed integrally with the wheel disc and is thereby permanently and rotationally fixed to the wheel disc.

[0035] A second aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle, preferably designed as a motor car, 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. Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and with reference to the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the description of the figures and / or in the single drawing, are to be understood as follows: Fig. The features and combinations of features shown in 1 alone can be used not only in the combinations shown, but also in other combinations or on their own, without leaving the scope of the invention.

[0036] The drawing shows in the only Fig. 1. Partially a schematic sectional view of a wheel hub drive for a motor vehicle.

[0037] The only Fig. Figure 1 shows a schematic longitudinal section of a wheel hub drive 10 for a motor vehicle, also referred to simply as a vehicle. The motor vehicle is preferably a car, in particular a passenger car. A vehicle wheel 12 of the motor vehicle can be driven by means of the wheel hub drive 10, in particular purely electrically, as will be explained in more detail below. The vehicle wheel 12 is a component of the wheel hub drive 10 and has a wheel disc 14 and a rim 16. In the Fig. In the embodiment shown in Figure 1, the wheel disc 14 and the rim 16 are designed separately from one another and are, in particular, permanently and non-rotatably connected to each other. The wheel hub drive 10 also has a wheel carrier 18 and a wheel bearing 20, which has a first bearing shell 22 that is, in particular, permanently and non-rotatably connected to the wheel carrier 18. Furthermore, the wheel bearing 20 has a second bearing shell 24 arranged coaxially and rotatably with respect to the first bearing shell 22 and rotatably with respect to a wheel axis of rotation D, which is arranged radially, i.e., in the radial direction of the wheel hub drive 10, within the first bearing shell 22. The wheel bearing 20 of the wheel hub drive 10, whose axial direction coincides with the wheel axis of rotation D, also referred to simply as the axis of rotation or main axis of rotation, is designed as a first rolling bearing.In the wheel hub drive 10, whose radial direction is perpendicular to the axial direction of the wheel hub drive 10 and thus perpendicular to the wheel axis of rotation D, the wheel carrier 18 and the first bearing shell 22 are designed separately from one another and, in particular, permanently and rotationally fixed to each other. For this purpose, for example, the bearing shell 22 is bolted to the wheel carrier 18, that is, screwed onto the wheel carrier 18. The feature that the bearing shell 24 is arranged coaxially and rotatably with respect to the bearing shell 22 and rotatably with respect to the wheel axis of rotation D means that the bearing shell 24 is rotatable about the wheel axis of rotation D relative to the bearing shell 22 and relative to the wheel carrier 18. Since the second bearing shell 24 is arranged radially inside the first bearing shell 22, the bearing shell 22 is a radially inner, first bearing ring of the wheel bearing 20, and the bearing shell 24 is a radially outer, second bearing ring of the wheel bearing 20.

[0038] At the in Fig. In the embodiment shown in Figure 1, the wheel bearing 20, designed as a rolling bearing, has two rolling bearings, in particular two separate ones, namely a first rolling bearing 26 and a second rolling bearing 28. The rolling bearing 26 has first rolling elements 30, which form a first row of rolling elements. The rolling bearing 28 has second rolling elements 32, which form a second row of rolling elements. The rows of rolling elements are arranged successively in the axial direction of the wheel hub drive 10. When the axial direction is mentioned below, this refers to the axial direction of the wheel hub drive 10 unless otherwise specified. When the radial direction is mentioned below, this refers to the radial direction of the wheel hub drive 10 unless otherwise specified. Furthermore, "axial" means the axial direction, and "radial" means the radial direction.In principle, it would be conceivable that the bearing shell 22 forms a first raceway for the rolling elements 30 and a second raceway for the rolling elements 32, so that when the bearing shell 24 rotates about the wheel axis of rotation D relative to the bearing shell 22, the rolling elements 30 roll directly on the first raceway and the rolling elements 32 on the second raceway. Alternatively or additionally, it would be conceivable that the bearing shell 24 forms a third raceway for the rolling elements 30 and a fourth raceway for the rolling elements 32, so that when the bearing shell 24 rotates about the wheel axis of rotation D relative to the bearing shell 22, the rolling elements 30 roll directly on the third raceway and the rolling elements 32 on the fourth raceway.

[0039] At the in Fig. In the embodiment shown in Figure 1, the rolling bearing 26 has a first outer bearing ring 34 and a first inner bearing ring 36. The first outer bearing ring 34 is formed as part of the bearing shell 22. The first inner bearing ring 36 is formed as part of the bearing shell 24. The inner bearing ring 36 is axially secured to, and in this case on, a connecting ring 92 by means of a retaining ring 38. The first inner bearing ring 36 is rotationally fixed to the connecting ring 92. The rolling elements 30 and 32 are designed as balls.The first outer bearing ring 34 now forms the aforementioned first raceway, and the first inner bearing ring 36 forms the aforementioned third raceway, so that when the bearing shell 24 and with it the inner bearing ring 36 rotate about the wheel axis D relative to the bearing shell 22 and relative to the outer bearing ring 34, the rolling elements 30 roll directly on the first raceway and on the third raceway respectively.

[0040] At the in Fig. In the embodiment shown in Figure 1, the second rolling bearing 28 has a second outer bearing ring 40 and a second inner bearing ring 42. The second outer bearing ring 40 is formed as part of the first bearing shell 22. The inner bearing ring 42 is formed as part of the second bearing shell 24. The second inner bearing ring 42 is rotationally fixed to the connecting ring 92. In the embodiment shown in Figure 1, the bearing 28 has a second outer bearing ring 40 and a second inner bearing ring 42. Fig. In the embodiment shown in Figure 1, the second outer bearing ring 40 forms the second raceway, and the second inner bearing ring 42 forms the fourth raceway, so that when the bearing shell 24 and thus the second inner bearing ring 42 rotate about the wheel axis of rotation D relative to the first bearing shell 22 and thus relative to the second outer bearing ring 40, the rolling elements 32 roll directly on the second raceway and the fourth raceway, respectively. In the embodiment shown in Fig. In the embodiment shown in Figure 1, the inner bearing rings 36, 42 particularly advantageously form the second bearing shell 24. The outer bearing rings 34, 40 particularly advantageously form the first bearing shell.

[0041] The vehicle wheel 12, and thus the wheel disc 14 and the rim 16, are formed separately from the bearing shells 22, 24 and are, in particular, permanently and rotationally fixed to the bearing shell 24. For this purpose, the wheel disc 14 is, in particular, permanently and rotationally fixed to the bearing shell 24. First screw elements 44 are provided on the bearing shell 24, which engage in corresponding openings 46 in the wheel disc 14, which in this case are designed as through-holes. Each screw element 44 has a first thread, which in this case is designed as a first external thread. A second screw element 48 is assigned to each first screw element 44, the screw elements 48 being formed separately from the bearing shells 22, 24 and separately from the vehicle wheel 12 and separately from each other.Each second screw element 48 has a second thread, in this case designed as an internal thread, which is screwed directly to the first thread of the first screw element 44 to which the second screw element 48 is assigned, in particular such that the first thread is screwed directly into the second thread and the second screw element 48 is screwed directly onto the corresponding first screw element 44 to which the second screw element 48 is assigned. Each screw element 48 is designed as a nut, also referred to as a wheel nut. It is also apparent that each second screw element 48 is at least partially received in the corresponding opening 46 of the wheel disc 14.Furthermore, it is provided that the screw elements 44 are formed in one piece with the bearing shell 24 and are therefore permanently rotationally fixed to the bearing shell 24, so that the screw elements 44 are formed in one piece with each other.

[0042] At the in Fig. In the embodiment shown in Figure 1, the wheel disc 14, which is connected to the second bearing shell 24 in a rotationally fixed manner, and the rim 16 are connected to each other in a rotationally fixed manner, in particular permanently, such that the wheel disc 14 and the rim 16 are designed separately from each other and are connected to each other in a rotationally fixed manner, in particular permanently.

[0043] The wheel hub drive 10 also includes an electric machine 50, which has a rotor 52 and a stator 54. The rotor 52 can be driven by means of the stator 54 and is thereby rotatable about a machine axis of rotation M relative to the stator 54. It can be seen that the rotor 52 is arranged coaxially with the bearing shell 24 and coaxially with the bearing shell 22, so that the machine axis of rotation M coincides with the wheel axis of rotation D. The rotor 52 is connected to the second bearing shell 24 in a rotationally fixed manner, in particular permanently. In the case of the Fig. In the embodiment shown in Figure 1, the rotor 52 is designed separately from the bearing shell 24 and separately from the vehicle wheel 12 and is, in particular, permanently and non-rotatably connected to the wheel disc 14. Furthermore, in the embodiment shown in Figure 1, the rotor 52 is designed separately from the bearing shell 24 and separately from the vehicle wheel 12 and is connected, in particular permanently, to the wheel disc 14 in a rotationally fixed manner. Fig. In the embodiment shown in Figure 1, the electric machine 50 is designed as an axial flux machine. The rotor 52 has two rotor elements, namely a first rotor element 56 and a second rotor element 58. The rotor elements 56 and 58 are separate from the bearing shells 22, 24 and separate from the vehicle wheel 12 and are, in particular, permanently and rotationally fixed to the wheel disc 14 and thus, in particular, permanently and rotationally fixed to the vehicle wheel 12, so that the rotor elements 56 and 58, and thus the rotor 52, are connected to the bearing shell 24 via the wheel disc 14, in particular permanently and rotationally fixed.At least a part T of the stator 54 is arranged axially, i.e. in the axial direction, between the axially, i.e. in the axial direction, successive and spaced apart from one another and opposite each other rotor elements 56 and 58, such that the rotor element 56 is at least partially, in particular at least predominantly and thus at least more than halfway or completely, overlapped by the part T in a first direction parallel to the axial direction and extending from the rotor element 56 to the rotor element 58, and that the rotor element 58 is at least partially, in particular at least predominantly and thus at least more than halfway or completely, overlapped by the part T in a second direction parallel to the axial direction and extending from the rotor element 58 to the rotor element 56 and opposite to the first direction.

[0044] A rotor carrier 60 for the electric machine 50 is also provided. The rotor elements 56 and 58, and thus the rotor 52, are formed separately from the rotor carrier 60 and are, in particular, permanently and rotationally fixed to the rotor carrier 60. A first part of the rotor carrier 60 is designated T1. The first part T1 could be formed separately from the wheel disc 14 and, in particular, be permanently and rotationally fixed to the wheel disc 14, or the first part T1 could be formed integrally with the wheel disc 14, meaning that the wheel disc 14 forms at least part of the rotor carrier 60. For example, the first part T1 is a wheel dish. A second part of the rotor carrier 60 is designated T2. For example, the second part T2 is formed separately from the first part T1 and, in particular, is permanently and rotationally fixed to the first part T1. For example, the second part T2 is a rotor cover.The electric machine 50 also has a stator support 62, which is, for example, a stator housing. For example, it is provided that the stator 54 and the stator support 62 are designed separately from one another and are, in particular, permanently and rotationally fixed to one another. The stator support 62, which in this case is designed, for example, as a stator housing, also has parts T3, T4, and T5, referred to as stator support components. The parts T3, T4, and T5 are, for example, designed separately from one another and, in particular, permanently and rotationally fixed to one another, in this case such that the parts T3, T4, and T5 are screwed together by means of screws 64 and are thereby, in particular, permanently and rotationally fixed to one another.

[0045] At the in Fig. In the embodiment shown in Figure 1, the rotor 52 is permanently connected to the bearing shell 24 in a rotationally fixed manner. In an alternative embodiment not shown, it would be conceivable that the rotor 52 could be connected to the bearing shell 24 in a rotationally fixed manner.

[0046] The wheel hub drive 10 has an elastic element 66, which is designed to elastically connect the stator 54 to the wheel carrier 18. This means that the stator 54 is elastically connected to the wheel carrier 18 via the elastic, and therefore elastically deformable, element 66, and is thus rotationally fixed to the wheel carrier 18. For this purpose, the elastic element 66 is located in the Fig. In the embodiment shown in Figure 1, the elastic element 66 is connected to the stator support 62 in a rotationally fixed manner, particularly such that the elastic element 66 is formed separately from the stator support 62 and is connected to the stator support 62 in a rotationally fixed manner, particularly permanently. Thus, for example, the elastic element 66, which is formed separately from the stator 54, is connected to the stator 54 via the stator support 62 in a rotationally fixed manner, particularly permanently. Alternatively or additionally, the elastic element 66 is formed separately from the bearing shell 22 and is connected to the bearing shell 22 in a rotationally fixed manner, particularly permanently, so that the elastic element 66 is connected to the wheel carrier 18, which is formed separately from the elastic element 66, in a rotationally fixed manner via the bearing shell 22.

[0047] To achieve a particularly advantageous operation of the wheel hub drive 10, the wheel hub drive 10 has a first support bearing 68, provided in addition to the wheel bearing 20 and thus in addition to the rolling bearings 26, 28. This first support bearing 68 has a third bearing shell 70, which is permanently and rotationally fixed to the second bearing shell 24, and a fourth bearing shell 72, which is permanently and rotationally fixed to the stator 54. In principle, it would be conceivable for the bearing shell 70 to be formed integrally with the bearing shell 24. In the case of the Fig. In the embodiment shown in Figure 1, however, the bearing shell 70 is designed separately from the bearing shell 24 and is, in particular, permanently and rotationally fixed to the bearing shell 24. In principle, it would be conceivable for the bearing shell 72 to be formed integrally with the stator 54 or integrally with the stator support 62. In the embodiment shown in Figure 1, the bearing shell 70 is designed separately from the bearing shell 24 and is, in particular, permanently and rotationally fixed to the bearing shell 24. Fig. In the embodiment shown in Figure 1, the bearing shell 72 is designed separately from the stator 54 and separately from the stator support 62 and is, in particular, permanently and rotationally fixed to the stator support 62, so that the bearing shell 72 is connected to the stator 54 via the stator support 62, in particular permanently and rotationally fixed. The third bearing shell 70 is arranged radially inside the fourth bearing shell 72 and radially outside the first bearing shell 22. While in this case the bearing shell 70 is an inner bearing ring of the support bearing 68, the bearing shell 72 is an outer bearing ring of the support bearing 68.

[0048] At the in Fig. In the embodiment shown in Figure 1, the support bearing 68 is designed as a rolling bearing, which, in particular, has additional rolling elements 74 in addition to the rolling elements 30 and 32. The rolling elements 74 are designed as balls. The bearing shells 70 and 72 each form a raceway for the rolling elements 74, which roll directly on the raceways of the bearing shells 70 and 72 when the bearing shell 70 rotates about the wheel axis D relative to the bearing shell 72.

[0049] In Fig. Figure 1 illustrates the tilting movements of the rotor 52 relative to the wheel carrier 18, represented by arrow 76. It is evident that the rotor 52 performs these tilting movements, illustrated by arrow 76 and relative to the wheel carrier 18, about a tilting axis A, which is perpendicular to an imaginary plane in which the wheel rotation axis D runs. This imaginary plane is represented by the image plane of Figure 1. Fig. 1 coincides. As illustrated by arrow 78, the tilting movements of the rotor 52 can be advantageously transmitted to the stator 54 via the support bearing 68. Because the stator 54 is elastically connected to the wheel carrier 18 by means of the elastic element 66, the stator 54 can perform, or does perform, the aforementioned tilting movements about the tilting axis A and relative to the wheel carrier 18. This allows, for example, an air gap arranged in the radial and / or axial direction between the stator 54 and the rotor 52 to be advantageously designed to be small, since, despite the tilting movements, there are no undesirable, excessive deformations or changes in the size of the air gap. This means that the air gap can be advantageously designed to be small without undesirable contact between the stator 54 and the rotor 52.

[0050] It can be seen that the elastic element 66 is arranged radially within the stator 54 or, in this case, radially within the stator support 62. Furthermore, the elastic element 66 is arranged radially within the fourth bearing shell 72. Additionally, the elastic element 66 is arranged axially, that is, in the axial direction and thus along the wheel rotation axis D, on a side S1 of the first support bearing 68 facing away from the wheel disc 14.

[0051] Recognizable from Fig. 1. It is also that the rotor carrier 60, in this case part T1, has a cylindrical section Z1 which is cylindrical at least on its outer circumference and is arranged radially outside the stator 54. Thus, in this case, the electric machine 50 is designed as an external rotor, and therefore as an external rotor machine.

[0052] The wheel hub drive 10 exhibits in the Fig. In the embodiment shown in Figure 1, a second support bearing 80 is provided, in particular in addition to the wheel bearing 20 and thus in addition to the rolling bearings 26 and 28 and in addition to the first support bearing 68. This second support bearing 80 is designed as a fourth rolling bearing. The support bearing 80 has rolling elements 82, which are designed as balls. The second support bearing 80 has a fifth bearing shell 84, which is permanently and rotationally fixed to the second bearing shell 24, and a sixth bearing shell 86, which is permanently and rotationally fixed to the stator. The fifth bearing shell 84 is arranged radially outside the sixth bearing shell 86. Thus, the bearing shell 84 is an outer bearing ring of the support bearing 80, and the bearing shell 86 is an inner bearing ring of the support bearing 80. In principle, it would be conceivable for the bearing shell 86 to be formed integrally with the bearing shell 22. In the embodiment shown in Figure 1, the bearing shell 86 is formed integrally with the bearing shell 22. Fig. In the embodiment shown in Figure 1, however, the bearing shell 86 is designed separately from the bearing shell 22, as well as separately from the stator 54 and separately from the stator support 62, wherein the bearing shell 86 is connected to the bearing shell 22 in a rotationally fixed manner, particularly permanently. Thus, the bearing shell 86 is connected to the elastic element 66 via the bearing shell 22 in a rotationally fixed manner, particularly permanently, and to the stator support 62 via the elastic element 66, and to the stator 54 via the stator support 62 in a rotationally fixed manner. In principle, it would be conceivable for the bearing shell 86 to be formed integrally with the rotor 52 or integrally with the rotor support 60. In the embodiment shown in Figure 1, the bearing shell 86 is designed in a single piece with the rotor 52 or integrally with the rotor support 60. Fig. In the embodiment shown in Figure 1, however, the bearing shell 84 is designed separately from the rotor 52 and separately from the rotor carrier 60 and is, in particular, permanently and rotationally fixed to the rotor carrier 60. In this case, the bearing shell 84, designed separately from the rotor 52 and separately from the rotor carrier 60, is, in particular, permanently and rotationally fixed to the rotor carrier 60. Thus, the bearing shell 84, designed separately from the rotor 52 and separately from the rotor carrier 60, is, in particular, permanently and rotationally fixed to the rotor 52 by means of the rotor carrier 60. The bearing shells 84 and 86 each form a raceway for the rolling elements 82, which then roll directly on the raceways of the bearing shells 84 and 86 when the bearing shell 84 rotates about the wheel axis of rotation D relative to the bearing shell 86.

[0053] The second support bearing 80 is arranged axially, that is, in the axial direction and thus along the wheel rotation axis D, on a second side S2 of the elastic element 66 facing away from the wheel disc 14.

[0054] At the in Fig.In the embodiment shown in Figure 1, the rim 16 and the wheel disc 14 are formed separately from one another. A first retaining ring 88 is provided, which is connected to the rim 16 in a rotationally fixed manner, and which is formed integrally with the rim 16 and is thus permanently and rotationally fixed to it. A second retaining ring 90 is also provided, which is connected to the wheel disc 14 in a rotationally fixed manner, and which is formed integrally with the wheel disc 14 and is thus permanently and rotationally fixed to it. The separately formed retaining rings 88 and 90 are connected to each other in a rotationally fixed manner, so that the wheel disc 14 and the rim 16 are connected to each other in a rotationally fixed manner via the retaining rings 88 and 90, in particular permanently.For example, the fastening rings 88 and 90 are screwed together and are therefore permanently, and thus permanently, connected to each other in a rotationally fixed manner. Reference symbol list 10 wheel hub drive 12 vehicle wheel 14 wheel disc 16 rim 18 bike carriers 20 wheel bearings 22 first bearing shell 24 second bearing cup 26 rolling bearings 28 rolling bearings 30 rolling elements 32 rolling elements 34 Outer bearing ring 36 inner bearing ring 38 retaining ring 40 Bearing outer ring 42 Inner bearing ring 44 screw element 46 Opening 48 screw element 50 electric machine 52 Rotor 54 Stator 56 Rotor element 58 Rotor element 60 rotor carriers 62 Stator carriers 64 screw 66 elastic element 68 first support bearing 70 third bearing cup 72 fourth bearing cup 74 rolling elements 76 Arrow 78 Arrow 80 second support bearing 82 rolling elements 84 fifth bearing cup 86 sixth bearing cup 88 Mounting ring 90 Mounting ring 92 Connecting ring A tilting axle D Wheel pivot axis M Machine rotary axis T part T1 Part T2 Part T3 Part T4 part T5 part Z1 Cylinder section

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (18), a wheel bearing (20) which has a first bearing shell (22) rotationally fixed to the wheel carrier (18) and a second bearing shell (24) arranged coaxially and rotatably to the first bearing shell (22) and rotatably to a wheel axis of rotation (D), which is arranged radially inside the first bearing shell (22), a vehicle wheel (12) which has a wheel disc (14) rotationally fixed to the second bearing shell (24) and a rim (16) rotationally fixed to the wheel disc (14), an electric machine (50) which has a rotor (52) rotationally fixed to or connectable to the second bearing shell (24) and a stator (54), and an elastic element (66) which is designed to elastically connect the stator (54) to the wheel carrier (18), characterized bya first support bearing (68) which has a third bearing shell (70) connected to the second bearing shell (24) in a rotationally fixed manner and a fourth bearing shell (72) connected to the stator (54) in a rotationally fixed manner, wherein the third bearing shell (70) is arranged radially inside the fourth bearing shell (72) and radially outside the first bearing shell (22). [2] Wheel hub drive (10) according to claim 1, characterized by , that the elastic element (66) is arranged radially inside the stator (54). [3] Wheel hub drive (10) according to claim 1 or 2, characterized by , that the elastic element (66) is arranged radially within the fourth bearing shell (72). [4] Wheel hub drive (10) according to any one of the preceding claims, characterized by , that the elastic element (66) is arranged axially on one side (S1) of the first support bearing (68) facing away from the wheel disc (14). [5] Wheel hub drive (10) according to any one of the preceding claims, characterized by, that a cylindrical section (Z1) of a rotor carrier (60) is arranged radially outside the stator (54). [6] Wheel hub drive (10) according to any one of the preceding claims, characterized by a second support bearing (80) which has a fifth bearing shell (84) connected to the second bearing shell (24) in a rotationally fixed manner and a sixth bearing shell (86) connected to the stator (54) in a rotationally fixed manner, wherein the fifth bearing shell (84) is arranged radially outside the sixth bearing shell (86). [7] Wheel hub drive (10) according to claim 6, characterized by , that the second support bearing (80) is arranged axially on one side (S2) of the elastic element (66) facing away from the wheel disc (14). [8] Wheel hub drive (10) according to any one of the preceding claims, characterized by, that the rim (16) is formed separately from the wheel disc (14), wherein a first retaining ring (88) connected to the rim (16) in a rotationally fixed manner and a second retaining ring (90) connected to the wheel disc (14) are designed to connect the wheel disc (14) and the rim (16) to each other in a rotationally fixed manner. [9] Motor vehicle, with at least one wheel hub drive (10) according to any of the preceding claims.

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