Wheel hub drive for a motor vehicle, in particular for a car, and motor vehicle, in particular car

Abstract

The invention relates to a wheel hub drive (10) for a motor vehicle, comprising a vehicle wheel (12) having a rim (14) and a wheel disc (16), a wheel carrier (18), a wheel bearing (22) having a first bearing shell (24) rotationally fixed to the wheel carrier (18) and a second bearing shell (28) rotatably arranged about a wheel axis of rotation (20) relative to the first bearing shell (24), an electric machine (48) having a stator (52) and a rotor (50), a coolant pump (54) for supplying coolant to the electric machine (48), and a spur gear stage (56) for driving the coolant pump (54), wherein a pump axis of rotation (58) of the coolant pump (54) is arranged parallel to the wheel axis of rotation (20). The rotor (50) is or can be connected rotationally fixed to the second bearing shell (28). The rotor (50) is arranged axially overlapping with the rim (14).The spur gear stage (56) is arranged axially overlapping with the rim (14).

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 2019 219 028 A1 discloses a known lubrication system for a wheel hub motor drive train, comprising a housing with a motor coupled to a first side thereof. Similarly, DE 10 2020 200 476 A1 for an electric vehicle drive and WO 2016 / 174 984 A1 for an electric wheel hub drive each disclose a lubrication pump connected to an electric drive via a spur gear drive.

[0003] DE 10 2007 037 833 A1 shows an electric vehicle drive with a lubricant pump also connected to an electric drive via a spur gear drive, wherein the spur gear stage is arranged axially overlapping with a rim.

[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, in such a way that a particularly advantageous cooling can be provided.

[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 7. 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, also referred to simply as a vehicle, which is preferably a motor car, 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 vehicle axles, also referred to simply as axles, arranged one behind the other and thus consecutively in the longitudinal direction of the motor vehicle, namely a first vehicle axle and a second vehicle axle.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 vehicle wheel comprises a rim and a wheel disc. In principle, it would be conceivable for the rim and the wheel disc to be formed separately and, in particular, permanently and rotationally fixed to each other. It has also proven advantageous for the wheel disc and the rim to be formed as a single unit and thus permanently and rotationally fixed to each other. The characteristic that two elements, such as the wheel disc and the rim, are formed as a single unit means that the elements are formed from a single piece and thus constitute a monoblock body, formed integrally from a single piece. It is conceivable that a tire, especially one made of rubber, is mounted on the rim, forming the tire separately from both the rim and the wheel disc, in which case the rim forms the tire.When the vehicle wheel rolls on the ground, the tire, especially directly, rolls on the ground, so that the tire directly touches the ground.

[0008] The wheel hub drive comprises a wheel carrier and a wheel bearing. The wheel bearing has a first bearing shell, which is permanently and non-rotatably connected to the wheel carrier, and a second bearing shell. The second bearing shell is rotatably mounted about a wheel axis of rotation relative to the first bearing shell and thus rotatably mounted relative to the wheel carrier. This means that the second bearing shell of the wheel hub drive, whose axial direction coincides with the wheel axis of rotation, is rotatable about the wheel axis of rotation relative to the first bearing shell and relative to the wheel carrier. More specifically, the second bearing shell is rotatably mounted on the first bearing shell about the wheel axis of rotation of the wheel hub drive, whose radial direction is perpendicular to the axial direction of the wheel hub drive and thus perpendicular to the wheel axis of rotation.For example, the second bearing shell, in particular permanently, is connected to the vehicle wheel, in particular the wheel disc, in a rotationally fixed manner, so that, for example, the second bearing shell, in particular permanently, is connected to the wheel disc and thus to the vehicle wheel in a rotationally fixed manner.

[0009] The wheel hub drive further comprises an electric machine consisting of a stator and a rotor. The rotor is driven by the stator and is thus rotatable about a machine axis of rotation relative to the stator. Preferably, the rotor, and therefore the electric machine, is arranged coaxially with the wheel bearing, so that the machine axis of rotation preferably coincides with the wheel axis of rotation and vice versa. 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. When the axial direction is mentioned before and after, it refers, unless otherwise specified, to the axial direction of the wheel hub drive.When the radial direction is mentioned before and below, unless otherwise specified, this refers to the radial direction of the wheel hub drive, whose circumferential direction runs around the wheel's axis of rotation and thus around the axial direction, lying in an imaginary plane perpendicular to the wheel's axis of rotation. In particular, by driving the rotor via the stator, the second bearing shell, and consequently the wheel disc and the vehicle wheel, can be driven, especially purely electrically.

[0010] Preferably, the electric machine is a high-voltage component whose electrical voltage, in particular electrical operating and / or nominal voltage, is preferably greater than 50 volts, in particular greater than 60 volts, and most preferably several hundred volts.

[0011] The wheel hub drive also includes a coolant pump, often simply referred to as a pump, which, by driving the coolant pump, circulates a coolant, preferably liquid, for the electric machine. Preferably, the coolant, also referred to as cooling fluid, is a component of the wheel hub drive. The coolant is used to cool the electric machine, or at least a part of it.

[0012] The pump's axis of rotation is arranged parallel to the wheel's axis of rotation. This means that the pump's axis of rotation runs parallel to the wheel's axis of rotation and is spaced apart from it.

[0013] For example, the coolant pump has a pump housing and a conveying element, which is arranged, in particular, at least partially within the pump housing. This conveying element, and thus the coolant pump, can be rotated about the pump's axis of rotation relative to the pump housing by driving the conveying element. By rotating the conveying element about the pump's axis of rotation relative to the pump housing, the coolant is conveyed by means of the conveying element and thus by means of the coolant pump, in particular such that the coolant, especially from a reservoir, can be conveyed to the electric machine, that is, at least to the relevant section of the electric machine. This allows the electric machine to be supplied with coolant, thereby enabling it to be cooled by means of the coolant. The wheel hub drive also has a spur gear stage for driving the coolant pump.This means that the spur gear stage can drive the coolant pump, and the coolant pump can be driven via the spur gear stage, in particular by a drive element. Specifically, the drive element is the rotor and / or the vehicle wheel. Driving the coolant pump means that, by driving the coolant pump, the pumping element can be driven and thus rotated about the pump's axis of rotation, particularly relative to the pump housing. Therefore, the pumping element can be driven by the spur gear stage and thus rotated about the pump's axis of rotation relative to the pump housing, so that, in particular, the pumping element can be driven via the spur gear stage by the drive element, i.e., by the rotor and / or the vehicle wheel, and thus rotated about the pump's axis of rotation relative to the pump housing.

[0014] To achieve particularly advantageous cooling of the electric machine, or at least of a specific section of the electric machine, it is provided, in a manner known per se, that the rotor is connected or connectable to the second bearing shell in a rotationally fixed manner. This means that the rotor can be permanently connected to the second bearing shell in a rotationally fixed manner. Alternatively, the rotor can be connected to the second bearing shell in a rotationally fixed manner. This means, for example, that a switching element is provided which can be switched between a coupled state and a decoupling state. In the coupled state, the rotor is connected to the second bearing shell in a rotationally fixed manner by means of the switching element, so that torques can be transmitted between the second bearing shell and the rotor via the switching element.In the decoupling state, the rotor is decoupled from the second bearing shell, so that no torques can be transmitted via the switching element between the rotor and the second bearing shell.

[0015] In particular, the electric machine can provide drive torques via its rotor for driving the vehicle wheel, especially purely electrically. With regard to a torque flow along which the respective drive torque can be transmitted from the rotor to the vehicle wheel, in particular by driving the vehicle wheel and thus rotating it about the wheel's axis of rotation relative to the first bearing shell and relative to the wheel carrier, the rotor is arranged upstream of the second bearing shell and upstream of the vehicle wheel, the second bearing shell downstream of the rotor and upstream of the vehicle wheel, and the vehicle wheel downstream of the second bearing shell and downstream of the rotor. It is specifically provided that, with regard to the torque flow, the wheel disc is arranged downstream of the second bearing shell and downstream of the rotor and upstream of the rim, and the rim is arranged downstream of the wheel disc.

[0016] Furthermore, it is provided in a known manner that the rotor is arranged axially overlapping the rim.

[0017] Furthermore, it is provided in a manner known per se that the spur gear stage is arranged axially overlapping with the rim.

[0018] The spur gear stage has two spur gears that mesh with each other, specifically a first spur gear and a second spur gear. Each spur gear is a separate gear.

[0019] Because the rotor is arranged axially overlapping the rim and because the rotor is rotationally fixed to the second bearing shell, the space required for the wheel hub drive can be kept particularly small. This allows for a particularly space-efficient supply of coolant to the electric motor and thus particularly space-efficient cooling of the electric motor. Furthermore, the space required for the wheel hub drive can be kept particularly small because the spur gear stage is arranged axially overlapping the rim.

[0020] Preferably, the coolant pump is a purely mechanical pump, which, for example, can be driven by the rotor and thus by the electric machine, but does not have its own separate electric motor for driving the pumping element, as would be the case with an electric pump. The coolant pump, i.e., the pumping element, can be driven by the rotor and / or preferably by the vehicle wheel, i.e., by its rotation, thus enabling a particularly advantageous supply of coolant to the electric machine.

[0021] By using the spur gear stage as an intermediate spur gear transmission, it is possible to convert a first rotational speed, at which the rotor and / or the vehicle wheel rotates about the wheel axis, particularly relative to the wheel carrier, into a second rotational speed of the coolant pump, i.e., the pumping element, which differs from the first rotational speed. This second rotational speed is then achieved by the pump rotating about the pump axis, particularly relative to the pump housing and, in particular, relative to the wheel carrier. Most preferably, the spur gear stage has a gear ratio such that the second rotational speed is greater than the first. This allows the coolant to be pumped particularly advantageously, especially effectively and efficiently, thereby providing particularly effective cooling for the electric machine.

[0022] Preferably, a coolant circuit through which the coolant flows is provided, and the coolant can be pumped through this circuit by means of a coolant pump. By driving the coolant pump, the coolant can be pumped and thus actively conveyed to the electric motor, thereby advantageously cooling the electric motor. This is particularly advantageous when the electric motor, and thus the wheel hub drive, has a high power density. After the coolant, also referred to as cooling fluid, has drained from the electric motor, the coolant pump can pump the coolant back to the electric motor, thereby closing the coolant circuit, which is also simply called the circuit or cooling circuit.

[0023] The prior art is based on the understanding that it would be possible, in principle, to use an electric, and thus electrically driven, pump to circulate the coolant. However, it has been found that this is very complex, as such an electric pump requires its own electric motor to drive the pumped medium. This separate electric motor increases the electrical power supply and the system weight and requires its own control system, which can now be avoided by the invention. In particular, the coolant pump is a mechanical, especially purely mechanical, pump that can be driven directly by or is driven by the vehicle wheel and has its own electric drive in addition to the electric motor.

[0024] Preferably, the volume and / or mass flow rate of the coolant that can be delivered by the coolant pump is adjustable. This means that at least two different values, each greater than zero, of the volume and / or mass flow rate of the coolant that can be delivered by the coolant pump, particularly to the electric machine, can be set. For this purpose, the coolant pump is designed, for example, as a variable and thus adjustable vane pump, so that the volume and / or mass flow rate of the coolant that can be delivered or is delivered by the coolant pump is adjustable, i.e., variable, and thus adaptable to the current cooling requirements, especially of the electric machine.

[0025] The spur gear stage is an intermediate gear stage. The fact that the spur gear stage is an intermediate gear stage, or spur gear transmission, means that the coolant pump, i.e., the pumping element, can be driven by the drive element via the spur gear stage. This allows the second speed, also referred to as the pump speed, to be changed, and in particular increased, relative to the first speed, also referred to as the wheel speed, thus enabling particularly efficient operation of the coolant pump.

[0026] Within the scope of this disclosure, the feature "radially overlapping" is to be understood as follows. Two elements, in particular those that are at least substantially rotationally symmetrical, are arranged in a radially overlapping manner with respect to a common axis, for example, extending in the radial direction, and / or in a radially overlapping manner, that is, with respect to each other, if they are each arranged at least partially in a region of the same radial coordinates, in particular the same angular coordinates. The term "radial" refers to the radial direction of the wheel hub drive. In other words, the term "radial" means the radial direction of the wheel hub drive.

[0027] The feature "axially overlapping" means the following: Two elements, such as the rotor and the rim, are arranged in an axially overlapping manner with respect to a common axis, particularly one extending in the axial direction, and / or an axial direction of the wheel hub drive, particularly with respect to each other, if they are each arranged at least partially in a region of the same axial coordinates. Within the scope of this disclosure, the term "axial" refers to the axial direction of the wheel hub drive. In other words, the term "axial" means the axial direction of the wheel hub drive. Put another way, "axial" refers to the axial direction of the wheel hub drive, and "radial" refers to the radial direction of the wheel hub drive.In other words, two elements are arranged in an axially overlapping manner, particularly with respect to each other, if, with respect to a common reference axis such as the wheel rotation axis and thus the axial direction of the wheel hub drive, they are at least partially arranged in a region of the same axial coordinates.

[0028] The characteristic that two elements are arranged without axial overlap, in particular with respect to each other, means that a first element is arranged without axial overlap with a second element if these two elements do not overlap axially, i.e., not at all and therefore not even partially, each other, i.e., if these elements are not, i.e., not at all or completely, arranged in an area of ​​the same axial coordinates.

[0029] The rim is a radially outer part of the vehicle wheel, onto which the tire may be mounted. For example, the rim has at least an approximately cylindrical shape. In particular, the rim is arranged coaxially with the wheel's axis of rotation. The wheel disc extends primarily in the radial direction, and the rim is connected to the second bearing race, particularly permanently, in a rotationally fixed manner via the wheel disc. In particular, the second bearing race is or forms a wheel hub. In particular, the second bearing race may, for example, be part of a wheel hub. Thus, for example, the vehicle wheel is connected to the wheel hub via the wheel disc, particularly permanently, in a rotationally fixed manner, and the rim may, in particular, be connected to the wheel hub via the wheel disc, particularly permanently, in a rotationally fixed manner.

[0030] The terms stator and rotor refer specifically to active parts, and not, for example, to their supports designed as stator and rotor carriers. In other words, stator and rotor refer to areas in which, for example, magnets and / or windings are arranged, by means of which a magnetic field can be generated to drive the rotor and thus rotate it around the machine's axis of rotation relative to the stator. Therefore, the feature that the rotor is arranged axially overlapping the rim means, in particular, that the rotor's magnets and / or at least one winding of the rotor are arranged axially overlapping the rim. The aforementioned magnetic field can be generated by means of the magnets or the windings of the rotor. Within the scope of this disclosure, the feature that a first component is arranged radially within a second component means that...that the first component is arranged in an area of ​​smaller, radially extending radii than the second component, particularly with respect to the wheel axis of rotation, at which, for example, the aforementioned radii begin. 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 containing the wheel hub drive, and particularly with respect to straight-ahead driving of the motor vehicle, that is, especially when the steering of the motor vehicle is set to effect straight-ahead driving, the first component, which is arranged axially within the second component, is positioned 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 arranged on a side of the second component facing the center of the motor vehicle, so that the first component, particularly when viewed in the transverse direction of the motor vehicle, is arranged further inwards, i.e. closer to the center of the motor vehicle, than the second component.

[0031] Within the scope of the present disclosure, the feature that two components, such as the second bearing shell and the wheel disc or the vehicle wheel, are connected to each other in a rotationally fixed manner, is to be understood as meaning that the components connected in a rotationally fixed manner are arranged coaxially to each other and, in particular when the components are driven, rotate together or simultaneously about a component rotation axis common to the components, such as the wheel rotation axis, with the same angular velocity, in particular relative to a reference element such as the wheel carrier.In other words, two elements are rotationally fixed to each other if they are arranged coaxially, particularly with respect to their component axis of rotation or with respect to a rotational symmetry axis, which may, for example, coincide with the component axis of rotation, and if they are connected in such a way that they always rotate at the same angular velocity. An element is rotationally fixed to a housing if it cannot be rotated relative to the housing. Thus, an element such as the first bearing race is rotationally fixed to the wheel carrier if it cannot be rotated relative to the wheel carrier.

[0032] In other words, the term "rotationally fixed" means the following: Two elements, in particular those mounted to rotate, are rotationally fixed to each other if they are arranged coaxially and are connected in such a way that they rotate at the same angular velocity, in particular around the axis of rotation of the component and / or relative to a reference element such as the wheel carrier.

[0033] The characteristic that two components are connected or coupled to each other 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 therefore be connected in a rotationally fixed manner.Furthermore, it is conceivable that two torque-transmitting components are connected to each other via an intermediate transmission and / or coupling unit, so that torques can be transmitted between the components via the transmission and / or coupling unit, while the components are connected to each other in a torque-transmitting manner, whereby the components can be rotatable relative to each other.

[0034] The characteristic that two components are permanently connected or coupled 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 in such a way that torque can be transmitted between them. Thus, for example, one of the components can be driven by the other, and vice versa.

[0035] The characteristic that two components, such as the wheel disc and the rim, or 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 permanently connected or coupled to each other in a rotationally fixed manner. Furthermore, the characteristic that two components can be connected or coupled to each other in a rotationally fixed manner means 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 rotationally fixed to one another by means of the switching element. In the decoupled state, the components are decoupled from each other, so that in the decoupled state the components can rotate relative to each other about the component axis of rotation and no torque can be transmitted between the components via the switching element, which is also referred to as the switching element. The same applies to the feature that two components can be connected or coupled to one another in a torque-transmitting manner. Thus, the feature that two components can be connected or coupled to one another 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 coupled state, also known as the connection state, the components are coupled or connected to each other via the switching element, allowing torque to be transmitted between the components and, in particular, via the switching element. In the uncoupled state, also known as the release state, the components are decoupled from each other, so that no torque can be transmitted between the components via the switching element.

[0036] To achieve particularly advantageous cooling of the electric machine, the spur gear stage is provided, in a known manner, with the aforementioned, in particular permanently meshing, spur gears, namely the first spur gear and the second spur gear. The spur gears are gears that are also referred to as first gears. It is preferably provided that the first spur gear can be driven by the rotor, and that by driving the first spur gear, the second spur gear can be driven by the first spur gear, so that the second spur gear can be driven by the rotor via the first spur gear.

[0037] With regard to the aforementioned torque flow, the spur gear stage is arranged downstream of the rotor and upstream of the coolant pump, in particular the conveying element, in particular such that the first spur gear is arranged downstream of the rotor and upstream of the second spur gear and upstream of the coolant pump or the conveying element, and that the second spur gear is arranged downstream of the rotor and downstream of the first spur gear and upstream of the coolant pump, i.e. downstream of the conveying element.

[0038] The pump's conveying element, designed as a conveying wheel, is arranged coaxially to the second spur gear in a known manner and can therefore be driven by the second spur gear, allowing the electric machine to be cooled in a particularly space-saving way.

[0039] According to the invention, the conveyor wheel is arranged on an axial side of the stator facing away from the wheel disc in the axial direction of the wheel hub drive, thereby enabling a particularly space-saving arrangement.

[0040] In order to achieve a particularly space-saving cooling of the electric machine, a further embodiment of the invention provides that the conveyor wheel, and thus the conveyor element, is arranged axially overlapping the rim.

[0041] Furthermore, it has proven particularly advantageous for achieving a particularly space-saving cooling of the electric machine if the conveyor wheel is arranged axially without overlap with the stator.

[0042] In order to keep the installation space requirement of the wheel hub drive particularly low, it is provided in a further embodiment of the invention that the conveyor wheel is arranged on an axial side of the spur gear stage facing away from the wheel disc in the axial direction of the wheel hub drive.

[0043] Another embodiment is characterized in that the second spur gear is permanently connected to the conveyor wheel in a rotationally fixed manner, resulting in a particularly small installation space requirement and a particularly low weight of the wheel hub drive.

[0044] Finally, it has proven particularly advantageous if the first spur gear is coaxial with the wheel's axis of rotation and connected to the second bearing shell in a rotationally fixed, and especially permanently rotationally fixed, manner. This allows the installation space required for the wheel hub drive to be kept to a particularly small level.

[0045] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle, and 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.

[0046] Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing.

[0047] The drawing shows in: Fig. 1 A schematic longitudinal sectional view of a wheel hub drive for a motor vehicle; and Fig. 2. Partially shown is another schematic longitudinal section view of the wheel hub drive.

[0048] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0049] Fig. Figure 1 shows a schematic longitudinal sectional view of a wheel hub drive 10 of a motor vehicle, also referred to simply as a vehicle, preferably a motor car, in particular a passenger car. Preferably, the motor vehicle, in its fully manufactured state, has at least or exactly two axles arranged consecutively in the longitudinal direction of the motor vehicle, namely a first axle and a second axle. Each axle has at least or exactly two wheels. The wheels of each axle are arranged on opposite sides of the motor vehicle in the transverse direction. The wheels of the motor vehicle are the ground contact elements of the motor vehicle.

[0050] The wheel hub drive 10 has, in particular, a first of the vehicle wheels, wherein the first vehicle wheel is in Fig. 1 is designated with 12. The first vehicle wheel is, for example, one of the vehicle wheels of the first vehicle axle. The vehicle wheel 12, also simply referred to as wheel, has a rim 14 and a wheel disc 16. In the case of the Fig. In the embodiment shown in Figure 1, the rim 14 and the wheel disc 16 are formed in one piece, i.e., from a single component. The wheel hub drive 10 also has a wheel carrier 18, wherein the vehicle wheel 12 is rotatable about a wheel axis of rotation 20, also referred to as the main axis of rotation, relative to the wheel carrier 18, in particular such that the vehicle wheel 12 is rotatably mounted on the wheel carrier 18 about the wheel axis of rotation 20 relative to the wheel carrier 18. For this purpose, a wheel bearing 22 is provided, by means of which the vehicle wheel 12 is rotatably mounted on the wheel carrier 18 about the wheel axis of rotation 20 relative to the wheel carrier 18. The wheel bearing 22 is designed as a rolling bearing, as will be explained in more detail below. The wheel bearing 22 has a first bearing shell 24 that is permanently and rotationally fixedly connected to the wheel carrier 18. In the embodiment shown in Figure 1, the wheel bearing 22 is a rolling bearing. Fig. In the embodiment shown in Figure 1, the bearing shell 24 and the wheel carrier 18 are formed integrally, that is, from a single piece. The first bearing shell 24 is a radially outer bearing shell of the wheel bearing 22. The wheel bearing 22 of the wheel hub drive 10, whose axial direction coincides with the wheel axis of rotation 20 and is illustrated by an arrow 26, has a second bearing shell 28, which is rotatably arranged about the wheel axis of rotation 20 relative to the first bearing shell 24. This means that the bearing shell 28 is rotatable about the wheel axis of rotation 20 relative to the bearing shell 24 and relative to the wheel carrier 18. The bearing shell 28 is rotatably mounted on the bearing shell 24 about the wheel axis of rotation 20 relative to the bearing shell 24. For this purpose, the wheel bearing 22 has several first rolling elements 30 and several second rolling elements 32.The rolling elements 30 form a first rolling element ring by being arranged successively in the circumferential direction of the wheel hub drive 10 around the wheel axis of rotation 20. The radial direction of the rolling elements 30 is perpendicular to the axial direction of the wheel hub drive 10 and thus perpendicular to the wheel axis of rotation 20. The rolling elements 32 form a second rolling element ring by being arranged successively in the circumferential direction of the wheel hub drive 10. The circumferential direction of the wheel hub drive 10 lies in an imaginary plane perpendicular to the axial direction of the wheel hub drive 10 and thus perpendicular to the wheel axis of rotation 20. This plane is illustrated by a double arrow 34. The radial direction of the wheel hub drive 10 is illustrated by a double arrow 36. When the axial direction is mentioned before and below, unless otherwise stated, this refers to the axial direction of the wheel hub drive 10.Here, "axial" refers to the axial direction. When the radial direction is mentioned before and after, this refers, unless otherwise specified, to the radial direction of the wheel hub drive 10, where "radial" means the radial direction. It can be seen that the second bearing shell 28 is a radially inner bearing shell, which is arranged at least partially radially inside the bearing shell 24. Conversely, the bearing shell 24 is arranged radially outside the bearing shell 28.

[0051] In the present case, the bearing shell 28 is a component of a wheel hub 38, which can, for example, be designed as a single piece, i.e., be made from a single piece.

[0052] At the in Fig. In the embodiment shown in Figure 1, the vehicle wheel 12, and thus the wheel disc 16 and the rim 14, are formed separately from the wheel hub 38 and are, in particular, permanently and rotationally fixed to the wheel hub 38 and thus, in particular, permanently and rotationally fixed to the bearing shell 28, such that the wheel disc 16 is, in particular, permanently and rotationally fixed to the wheel hub 38 and thus, in particular, permanently and rotationally fixed to the second bearing shell 28. For this purpose, for example, the wheel disc 16 is screwed to the wheel hub 38 and thus to the bearing shell 28. It is thus evident that the vehicle wheel 12 is, in particular, permanently and rotationally fixed to the bearing shell 28, in this case to the wheel hub 38, via the wheel disc 16.

[0053] The rolling elements 30 are assigned a first raceway and a second raceway, the second raceway being arranged, for example, radially within the first raceway. The rolling elements 32 are assigned a third raceway and a fourth raceway, the fourth raceway being arranged, for example, radially within the third raceway. In principle, it would be conceivable that the first and third raceways are formed by the bearing shell 24 itself. Furthermore, it would be conceivable that the second and fourth raceways are formed by the bearing shell 28 itself. In the case of the Fig. In the embodiment shown in Figure 1, however, the first raceway is formed by a first bearing ring 40, which is also referred to as the first outer bearing ring. The second raceway is formed by a second bearing ring 42, which is also referred to as the first inner bearing ring. The third raceway is formed by a third bearing ring 44, which is also referred to as the second outer bearing ring. The fourth raceway is formed by a fourth bearing ring 46, which is also referred to as the second inner bearing ring. The bearing rings 40, 42, 44, and 46 are formed separately from each other and separately from the bearing shells 24 and 28. The bearing rings 40 and 44 are supported on the bearing shell 24, in particular such that relative movements between the respective bearing rings 40 and 44 and the bearing shell 24 are prevented.The bearing rings 42 and 46 are supported on the bearing shell 28, in particular in such a way that relative movements between the respective bearing ring 42, 46 and the bearing shell 28 are prevented.

[0054] The wheel hub drive 10 comprises an electric machine 48, which has a rotor 50 and a stator 52. The stator 52 is connected to the wheel carrier 18 in a rotationally fixed manner, at least indirectly, and in particular permanently. The rotor 50 can be driven by means of the stator 52 and is thereby rotatable about the wheel axis of rotation 20 relative to the wheel carrier 18. It can be seen that the wheel disc 16 and the vehicle wheel 12 as a whole, as well as the stator 52, the rotor 50, and the bearing shells 24 and 28, are all arranged coaxially with each other and coaxially with the wheel axis of rotation 20. Via its rotor 50, the electric machine 48 can provide drive torques by means of which the stator 52, and via the stator 52 the bearing shell 28, can be driven and are thereby rotatable about the wheel axis of rotation 20 relative to the stator 52 and relative to the wheel carrier 18. By driving the bearing shell 28, the vehicle wheel 12 can be driven and thus rotated about the wheel axis 20 relative to the wheel carrier 18.Thus, the stator 52 can drive the vehicle wheel 12 by driving the rotor 50.

[0055] The wheel hub drive 10 also includes a coolant pump 54, also referred to simply as a pump, for pumping a coolant, which is primarily liquid and also simply referred to as cooling fluid. The coolant is a coolant for the electric machine 48. This means that at least a portion of the electric machine 48 can be supplied with the coolant pumped by the pump, so that at least the portion of the electric machine 48 can be cooled by means of the coolant with which the electric machine 48 can be supplied or is supplied.

[0056] The wheel hub drive 10 also has a spur gear stage 56, by means of which the coolant pump 54 can be driven, in this case such that the rotor 50 and the vehicle wheel 12 can drive the coolant pump 54 via the spur gear stage 56. By driving the coolant pump 54, the coolant pump 54 pumps the coolant, in particular from a reservoir, to the electric machine 48, that is, at least to that part of the electric machine 48, thereby supplying the electric machine 48, or at least that part of the electric machine 48, with coolant. This means that by rotating the vehicle wheel 12 about the wheel axis 20 and relative to the wheel carrier 18, the coolant pump 54 can be driven, in particular via the spur gear stage 56, in order to pump the coolant, in particular to the electric machine 48, by means of the coolant pump 54.

[0057] In the wheel hub drive 10, a pump rotation axis 58 of the coolant pump 54 is arranged parallel to the wheel rotation axis 20.

[0058] In order to achieve a particularly space-saving and therefore particularly advantageous cooling of the electric machine 48, the rotor 50 is or can be connected to the second bearing shell 28 in a rotationally fixed manner. In the case of the Fig. In the embodiment shown in Figure 1, the rotor 50 is permanently and rotationally fixed to the second bearing shell 28. Furthermore, the rotor 50 is arranged axially overlapping the rim 14. In addition, the spur gear stage 56 is arranged axially overlapping the rim 14.

[0059] Fig. Figure 2 shows an enlarged view of an area of ​​the wheel hub drive 10. Particularly good is the view from Fig. Figure 2 shows the coolant pump 54 and the spur gear stage 56, also referred to as a spur gear pair. The spur gear stage 56 has two spur gears that mesh with each other, specifically permanently: a first spur gear 59 and a second spur gear 60. The first spur gear 59 can be driven by the rotor 50 and is therefore rotatable about the wheel axis 20 relative to the wheel carrier 18. This means that the first spur gear 59 is arranged coaxially with the wheel axis 20. The second spur gear 60 meshes with the first spur gear 59 and is driven by the first spur gear 59 and is therefore rotatable about the pump axis 58 relative to the wheel carrier 18. Thus, the second spur gear 60 is arranged coaxially with the pump axis 58. The second spur gear 60 is therefore driven by the rotor 50 via the first spur gear 59 and is therefore rotatable about the pump axis 58 relative to the wheel carrier 18.

[0060] Recognizable from Fig. Section 2 states that the coolant pump 54 comprises a pump housing 62 and a conveying element arranged in the pump housing 62 and designed as an impeller 64, which can be rotated about the pump axis of rotation 58 relative to the pump housing 62 by driving the impeller 64. By rotating the impeller 64 about the pump axis of rotation 58 and relative to the pump housing 62, the coolant, in particular from the reservoir, can be conveyed to the electric machine 48 by means of the impeller 64 and thus by means of the coolant pump 54. The impeller 64 and the second spur gear 60 are arranged coaxially with each other and coaxially with the pump axis of rotation 58. By driving the second spur gear 60 by means of the first spur gear 59, the impeller 64 can be driven and thereby rotated about the pump axis of rotation 58 relative to the pump housing 62 and relative to the impeller carrier 18. Thus, the coolant pump 54 can be driven by driving the impeller 64. In the case of the Fig. In the embodiment shown in 2, the second spur gear 60 is connected, in particular permanently, to the conveyor gear 64 in a rotationally fixed manner.

[0061] A fluid inlet of the coolant pump 54, in particular of the pump housing 62, is designated 66, and a fluid outlet of the coolant pump 54, in particular of the pump housing 62, is designated 68. By rotating the impeller 64 about the pump axis of rotation 58 and relative to the pump housing 62, the coolant, also referred to as fluid, can be drawn from the reservoir by means of the impeller 64 and thus conveyed towards it, and thereby conveyed through the fluid inlet 66 and thus into the pump housing 62 via the fluid inlet 66.By rotating the impeller 64 around the pump axis 58 and relative to the pump housing 62, the impeller 64 can convey the coolant conveyed towards it through the pump housing 62 and thereby convey from the fluid inlet 66 to the fluid outlet 68, convey through the fluid outlet 68 and thereby convey the coolant away from itself and out of the pump housing 62 and towards the section of the electric machine 48, i.e. towards the electric machine 48, whereby the electric machine 48 can be supplied or is supplied with the coolant.

[0062] In Fig.Figure 1 illustrates the coolant flowing through the fluid inlet 66 and thus towards the impeller 64. Figure 72 illustrates the coolant flowing through the fluid outlet 68 and thus out of the pump housing 62, away from the impeller 64, and towards the electric motor 48.

[0063] Arrows 74 illustrate an actuation of the coolant pump 54, also referred to as actuation. This means that the coolant pump 54 is an adjustable, and therefore variable, pump, so that the volume and / or mass flow rate of the coolant delivered by the pump can be adjusted, i.e., varied. Through this actuation of the pump, the volume and / or mass flow rate of the coolant delivered by the pump can thus be set, i.e., varied, and therefore adjusted to several different values ​​that are greater than zero. For this purpose, the coolant pump 54 (pump) is, for example, designed as a variable vane pump.

[0064] It can be seen that the conveyor wheel 64 is arranged axially overlapping the rim 14. The conveyor wheel 64 is arranged axially without overlap with the stator 52. The conveyor wheel 64 is arranged on an axial side S1 of the stator 52 facing away from the wheel disc 16 in the axial direction of the wheel hub drive 10. The conveyor wheel 64 is arranged on an axial side S2 of the spur gear stage 56 facing away from the wheel disc 16 in the axial direction of the wheel hub drive 10. The second spur gear 60 is, in particular permanently, rotationally fixed to the conveyor wheel 64. The first spur gear 59 is arranged coaxially with the wheel axis of rotation 20. The first spur gear 59 is, in particular permanently, rotationally fixed to the second bearing shell 28 and thus, in this case, to the wheel hub 38. For this purpose, the bearing shell 28 has a first toothing 78, in particular on its inner circumference 76.The design includes a gear 80, formed separately from the bearing shell 28 and, for example, configured as a third spur gear, which has a second tooth 82 corresponding to the tooth 78. Preferably, the respective tooth 78 and 82 are designed as interlocking teeth. The tooth 78 and 82 mesh with each other, thereby permanently and rotationally fixedly connecting the gear 80 and the bearing shell 28, which is formed separately from the gear 80.

[0065] The gear 80 is permanently and rotationally fixed to a first shaft 84. The first spur gear 59 is also permanently and rotationally fixed to the shaft 84. This allows the spur gear 59 to be driven by the shaft 84, which in turn is driven by the gear 80, which in turn is driven by the bearing shell 28. Thus, the spur gear 59 can be driven by the gear 80 via the shaft 84, and the shaft 84 can be driven by the bearing shell 28 via the gear 80.

[0066] A second shaft 86 is also provided, wherein the impeller 64, the shaft 86, and the spur gear 60 are all arranged coaxially to each other and coaxially to the pump's axis of rotation 58. The spur gear 60 is, in particular, permanently and rotationally fixed to the shaft 86. The impeller 64 is, in particular, permanently and rotationally fixed to the shaft 86.

[0067] Thus, shaft 86 can be driven by spur gear 60, which in turn can be driven by spur gear 59. Conveyor wheel 64 can be driven by shaft 86, so that conveyor wheel 64 can be driven by spur gear 60 via shaft 86.

[0068] The coolant illustrated by arrow 70 and flowing towards the coolant pump 54 comes, for example, from a fluid cooler, which is used to cool the coolant.

[0069] The interposed spur gear stage 56 makes it possible to increase the rotational speed of the vehicle wheel 12 to a correspondingly higher rotational speed of the pump, i.e., the impeller 64, so that the pump can be advantageously designed with a smaller geometric shape. Furthermore, this allows the pump to be operated particularly efficiently. Preferably, the spur gear stage 56, especially from the spur gear 59 to the spur gear 60, and thus, for example, from the bearing shell 28 to the impeller 64, has a higher gear ratio than 0 and compared to 1, which is preferably in the range of 3 to 10 inclusive.

[0070] Because the volume and / or mass flow rate of the coolant delivered by the pump is adjustable, the electric machine 48 can be supplied with coolant according to demand. This enables particularly efficient operation of the wheel hub drive 10, as excessive mechanical losses, especially those resulting from unnecessarily large volume and / or mass flow rates of the coolant, can be avoided.

[0071] The variable vane pump is a type of pump in which the pump eccentricity can be changed, i.e., varied, by axially displacing an adjusting ring inside the pump, i.e., in the pump housing 62. This allows the volume and / or mass flow rate of the coolant delivered by the pump to be adjusted, i.e., varied. If the pump eccentricity is 0, the respective center axes of the adjusting ring and the pump axis of rotation 58 coincide, so that the coolant pump 54 does not deliver any coolant, especially despite the rotation of the impeller 64 relative to the pump housing 62 and about the pump axis of rotation 58.At maximum pump eccentricity, that is, when the pump eccentricity has its maximum value, the impeller 64, when rotating about the pump axis 58 relative to the pump housing 62, delivers a maximum flow rate, that is, the largest possible volume and / or mass flow rate of the coolant, especially at a given rotational speed of the impeller 64.

[0072] The coolant is conveyed, for example, from the electric machine 48, in particular from the stator 52, to the fluid cooler, which is permanently installed in the vehicle, via a coolant line. The coolant is cooled by the fluid cooler, referred to simply as the cooler, in particular in such a way that the cooler is exposed to airflow, especially when the vehicle is in motion. The coolant flowing through the cooler can be cooled by the ambient air flowing around it. From the cooler, the coolant can be conveyed, in particular via another coolant line, back to the pump. The pump circulates the coolant in and through cooling channels, in particular of a stator carrier, in particular to cool it.

[0073] In other words, it is conceivable that the aforementioned subsection of the electric machine 48 comprises at least a part of the stator 52 and / or the stator support and / or the rotor 50 and / or a rotor carrier, such that, for example, the stator 52 and / or the stator support and / or the rotor 50 and / or the rotor carrier can be cooled by means of the coolant. Thus, for example, at least one cooling channel through which the coolant flows runs through the rotor 50 and / or through the rotor carrier and / or through the stator 52 and / or through the stator carrier, and the coolant can be pumped through the cooling channel. Reference symbol list 10 wheel hub drive 12 vehicle wheel 14 rim 16 wheel disc 18 bike carriers 20 Wheel pivot axle 22 wheel bearings 24 first bearing cup 26 Double Arrow 28 second bearing cup 30 first rolling element 32 second rolling element 34 Double Arrow 36 Double Arrow 38 Wheel hub 40 bearing ring 42 Bearing ring 44 Bearing ring 46 bearing ring 48 electric machine 50 Rotor 52 Stator 54 Coolant pump 56 Spur gear stage 58 Pump axis 59 first spur gear 60 second spur gear 62 Pump housings 64 conveyor wheel 66 Fluid inlet 68 Fluid outlet 70 Arrow 72 Arrow 74 Arrow 76 inner circumference 78 gear teeth 80 gear 82 gear teeth 84 wave 86 wave S1 axial side S2 axial side

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a vehicle wheel (12) having a rim (14) and a wheel disc (16), a wheel carrier (18), a wheel bearing (22) having a first bearing shell (24) rotationally fixed to the wheel carrier (18) and a second bearing shell (28) rotatably arranged about a wheel axis of rotation (20) relative to the first bearing shell (24), an electric machine (48) having a stator (52) and a rotor (50), a coolant pump (54) for supplying coolant to the electric machine (48), and a spur gear stage (56) for driving the coolant pump (54), wherein a pump axis of rotation (58) of the coolant pump (54) is arranged parallel to the wheel axis of rotation (20), where - the rotor (50) is or can be connected to the second bearing shell (28) in a rotationally fixed manner; - the rotor (50) is arranged axially overlapping with the rim (14); - the spur gear stage (56) is arranged axially overlapping with the rim (14) and has two meshing spur gears (59, 60), namely a first spur gear (59) driven by the rotor (50) and a second spur gear (60) driven by the first spur gear (59) and thereby via the first spur gear (59) by the rotor (50); - the coolant pump (54) has a pump impeller (64) which is arranged coaxially to the second spur gear (60) and can be driven by the second spur gear (60); characterized by , that the conveyor wheel (64) is arranged on an axial side (S1) of the stator (52) facing away from the wheel disc (16) in the axial direction of the wheel hub drive (10). [2] Wheel hub drive (10) according to claim 1, characterized by , that the conveyor wheel (64) is arranged axially overlapping with the rim (14). [3] Wheel hub drive (10) according to claim 1 or 2, characterized by, that the conveyor wheel (64) is arranged axially without overlap with the stator (52). [4] Wheel hub drive (10) according to one of claims 1 to 3, characterized by , that the conveyor wheel (64) is arranged on an axial side (S2) of the spur gear stage (56) facing away from the wheel disc (16) in the axial direction of the wheel hub drive (10). [5] Wheel hub drive (10) according to one of claims 1 to 4, characterized by , that the second spur gear (60) is connected to the conveyor gear (64) in a rotationally fixed manner. [6] Wheel hub drive (10) according to one of claims 1 to 5, characterized by , that the first spur gear (59) is coaxial to the wheel axis of rotation (20) and is non-rotatably connected to the second bearing shell (28). [7] Motor vehicle, with at least one wheel hub drive (10) according to one of the preceding claims.

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