Wheel hub drive for a motor vehicle, in particular for a car, as well as motor vehicle

Abstract

The invention relates to a wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (20), a wheel hub (22) rotatably mounted on the wheel carrier (20) via a wheel bearing (24), to which a vehicle wheel (12) of the motor vehicle can be connected in a rotationally fixed manner, an electric machine (30) which has a stator (32) rotationally fixed to the wheel carrier (20) and a rotor (34) which can be driven by means of the stator (32) and is thereby rotatable relative to the stator (32), which is rotatably mounted on the wheel hub (22) via a rotor bearing (42) provided in addition to the wheel bearing (24), and a positive-locking coupling device (44) which can be switched between a coupling state (K), in which the rotor (34) is positively locked and rotationally fixed to the wheel hub (22) by means of the coupling device (44), and a decoupling state (E), in which the rotor (34) is rotatable relative to the wheel hub (22).

Description

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

[0002] JP 2020-128 134 A is a vehicle drive unit comprising a vehicle bearing and an electric motor with a rotor and stator as known from the patent. The rotor is mounted coaxially to an inner ring. The vehicle drive unit also includes a coupling that switches the rotor between a connected state for rotational transmission with the inner ring and a disconnected state.

[0003] DE 10 2013 202 809 A1 describes an actuating device for a torque transmission device, such as a clutch, as is known. The torque transmission device has at least two electric motors, the rotors of which are kinematically coupled to each other via a summing gear.

[0004] German patent application DE 10 2011 100 060 A1 discloses a drive train for a motor vehicle with an electric motor comprising a stator and a rotor. The drive train has a driven axle that is permanently coupled to the electric motor and can be selectively coupled to at least one wheel of the motor vehicle via a disconnect clutch.

[0005] German patent DE 41 27 257 A1 discloses a small vehicle, in particular a wheelchair, as known, with a frame having at least two wheels, each of which can be driven by a DC motor with gearbox arranged in the region of its hub. The object of the present invention is to provide a wheel hub drive for a motor vehicle and a motor vehicle with such a wheel hub drive, enabling particularly efficient operation. This object is achieved by a wheel hub drive with the features of claim 1 and by a motor vehicle with the features of claim 10. 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 for a motor vehicle, in particular for a car. This means that the motor vehicle, preferably designed as a car, especially a passenger car, has the wheel hub drive in its fully manufactured state. In particular, the motor vehicle in its fully manufactured state has at least one vehicle wheel, also simply referred to as a wheel, which is a ground contact element of the motor vehicle. The motor vehicle can be supported or is supported downwards against a ground via its ground contact element in the vertical direction of the vehicle. If the motor vehicle is driven along the ground while the motor vehicle is supported downwards against the ground via the vehicle wheel in the vertical direction of the vehicle, the vehicle wheel rolls, in particular directly, along the ground.As will be explained in more detail below, the wheel hub drive can be used to drive the vehicle wheel, especially purely, electrically, in order to realize, for example, a purely electric drive of the motor vehicle.

[0007] The wheel hub drive comprises a wheel carrier and a wheel hub, which are rotatably mounted on the wheel carrier via a wheel bearing. Preferably, the wheel bearing is a first rolling bearing. In other words, the wheel hub is rotatably mounted on the wheel carrier about a wheel rotation axis relative to the wheel carrier, specifically via the wheel bearing. The aforementioned vehicle wheel is rotatably connected to the wheel hub. For this purpose, the wheel hub has, for example, a so-called rim carrier, to which, for example, the vehicle wheel, in particular a rim of the vehicle wheel, can be rotatably connected.In particular, the vehicle wheel is reversibly and detachably connected or connected to the wheel hub, especially to the rim carrier, in a rotationally fixed manner, so that the vehicle wheel can be connected to the wheel hub, especially to the rim carrier, in a rotationally fixed manner, and subsequently detached from the wheel hub and then reconnected to the wheel hub in a rotationally fixed manner without causing damage or destruction to the wheel hub or the wheel. In particular, when the vehicle is driven along the ground while the vehicle is supported downwards by the vehicle wheel in the upward direction, the wheel hub and thus the vehicle wheel rotate about the wheel's axis of rotation relative to the wheel carrier.

[0008] For example, the wheel carrier is articulated to the vehicle body, which may be designed as a unibody, via at least one control arm (also simply called a steering link), so that the wheel carrier, and thus the vehicle wheel, is guided relative to the body by means of the control arm. This prevents undesirable or excessive relative movements between the wheel carrier and the body, and therefore between the vehicle wheel and the body. For example, the wheel carrier, and thus the vehicle wheel, is articulated to the body via the control arm in such a way that the control arm allows for compression and rebound movements of the wheel carrier, and thus the vehicle wheel, relative to the body, at least in the vertical direction of the vehicle.

[0009] The vehicle wheel comprises, for example, the aforementioned rim and a tire, which is mounted on the rim. The rim, and thus the vehicle wheel, can be connected to the wheel hub, in particular to the rim carrier of the wheel hub, in a rotationally fixed manner, especially by means of several wheel bolts. The wheel hub drive also includes, in particular, an electric machine, which has a stator and a rotor that are rotationally fixed to the wheel carrier. The rotor can be driven by means of the stator, in particular by using electrical energy, and is thereby rotatable relative to the stator, in particular about a machine axis of rotation. In particular, the rotor is arranged coaxially with the wheel hub, so that the machine axis of rotation preferably coincides with the wheel axis of rotation. In particular, the rotor can be driven by means of the stator and thereby rotated relative to the wheel carrier about the machine axis of rotation, in particular the wheel axis of rotation.As will be explained in more detail below, the rotor can be used to drive the wheel hub and thus the vehicle wheel, and therefore rotate it, particularly around the wheel's axis of rotation, relative to the wheel carrier. Thus, the electric machine can provide at least a drive torque via its rotor, which is sufficient to drive the wheel hub and therefore the vehicle wheel, and thus rotate it around the machine's axis of rotation and / or around the wheel's axis of rotation relative to the wheel carrier and, in particular, also relative to the vehicle body.

[0010] The rotor is rotatably mounted on the wheel hub via, in particular at least or exactly, a rotor bearing provided in addition to the wheel bearing. Preferably, the rotor bearing is designed as a second rolling bearing. This means that the rotor is rotatably mounted on the wheel hub via the rotor bearing about the machine axis of rotation and thus preferably about the wheel axis of rotation relative to the wheel hub. Therefore, it is particularly conceivable that the rotor and the wheel hub can rotate relative to each other about the machine axis of rotation and / or about the wheel axis of rotation, respectively. Furthermore, the rotor can rotate about the machine axis of rotation and / or about the wheel axis of rotation relative to the wheel carrier, and the wheel hub can rotate about the wheel axis of rotation relative to the wheel carrier.

[0011] The wheel hub drive also features a positive-locking coupling device that can be switched between a coupled state and a decoupling state, particularly using electrical energy and / or hydraulically and / or pneumatically. In the coupled state, the rotor is positively and rotationally fixedly connected to the wheel hub by means of the coupling device, so that in the coupled state the rotor and the wheel hub can rotate about the wheel axis or the machine axis, in particular together or simultaneously, at the same angular velocity, especially when the rotor and, via the rotor, the wheel hub are driven by the stator. In the decoupling state, the rotor is rotatable relative to the wheel hub, in particular about the machine axis or the wheel axis, and vice versa.In other words, the coupling device, when decoupled, allows relative rotations between the rotor and the wheel hub around the wheel axis or the machine axis, so that in the decoupling state the rotor is decoupled from the wheel hub, or vice versa. Thus, if, for example, the vehicle wheel and, with it, the wheel hub rotate around the wheel axis or the machine axis relative to the wheel carrier in the decoupling state, the rotor is not driven by the wheel hub; consequently, the wheel hub does not drag the rotor along, enabling particularly efficient operation. In other words, a particularly high efficiency of the wheel hub drive can be achieved, allowing for a particularly long electric range over which the vehicle wheel can be driven by the wheel hub drive using electrical energy.The wheel hub drive is an electric traction drive because it allows the vehicle wheel, and thus the vehicle itself, to be driven electrically, especially in purely electric mode. In particular, because the rotor can be decoupled from the wheel hub, losses, especially those caused by drag torque, can be kept to a minimum, resulting in a particularly high efficiency of the wheel hub drive. Compared to conventional solutions, the fixed connection between the rotor and the wheel hub is eliminated and replaced by a coupling device that can be switched between decoupling and coupling as needed. It has been found that, compared to a wheel hub drive where the rotor is permanently fixed to the wheel hub, a range increase of several percent can be achieved.For example, the wheel hub drive according to the invention can be used to implement a switchable and switchable all-wheel drive system for the motor vehicle. For example, in its fully manufactured state, the motor vehicle has at least or exactly two axles arranged consecutively in the longitudinal direction, each axle having at least or exactly two wheels. The wheels of each axle are arranged, for example, on opposite sides of the motor vehicle in the transverse direction. One of the wheels is the aforementioned wheel driven by the wheel hub drive and is also referred to as the first wheel. The first wheel is one of the wheels of a first axle, just as the first axle has the first wheel and a second wheel.For example, the second wheel can be driven by means of another wheel hub drive, whereby the preceding and following explanations regarding the first wheel hub drive and the first wheel can readily be applied to the second wheel hub drive and the second wheel. The wheels of the second axle are also referred to as the third wheels and can be driven, for example, by means of at least one additional drive motor provided alongside the wheel hub drives, whereby the drive motor can be, for example, an internal combustion engine or another electric motor. In order to drive, for example, the first and second wheels by means of the wheel hub drives, and in particular in addition to driving the third wheels by means of the drive motor, the respective wheel hub is connected to the respective rotor in a rotationally fixed manner by means of the respective coupling device.For this purpose, at least four or exactly four of the vehicle's wheels can be driven, thus enabling four-wheel drive and therefore the aforementioned all-wheel drive, meaning it is activated or engaged. When the all-wheel or four-wheel drive is deactivated, the respective coupling device is in its respective decoupling state. If the third set of vehicle wheels is then driven by the drive motor, thus propelling the vehicle, so that, for example, the four vehicle wheels roll on the aforementioned ground, the first and second vehicle wheels, or the wheel hubs of the wheel hub drives, do not drag the rotors, enabling particularly efficient operation.In particular, when the coupling devices are in their decoupling states while the third vehicle wheels are driven by the drive motor, the motor vehicle can be driven with particularly low energy consumption and thus over a particularly long, especially electric, range, since the wheel hubs of the wheel hub drives do not drag the rotors of the wheel hub drives.

[0012] Furthermore, because the coupling device is designed as a positive-locking coupling device, losses in the wheel hub drive can be kept particularly low, so that a particularly high efficiency can be achieved.

[0013] In order to couple the rotor to the wheel hub particularly efficiently, in a space-saving and weight-efficient manner, one embodiment of the invention provides that the coupling device, in particular at least or exactly, has a first coupling toothing connected to the rotor in a rotationally fixed manner and, in particular, at least or exactly, a wider coupling toothing connected to the wheel hub in a rotationally fixed manner. In the coupled state, the rotor is positively locked and rotationally fixed to the wheel hub by means of the coupling teeth.

[0014] A further embodiment of the invention is characterized in that the first coupling toothing is arranged at a radially inner end and axially on a side of the rotor facing the interior of the vehicle, particularly in the installed position of the wheel hub drive, which assumes its installed position in the fully manufactured state of the vehicle equipped with the wheel hub drive. In other words, it is preferably provided that the first coupling toothing is arranged on an inner circumferential surface of the rotor, for example, pointing inwards in the radial direction of the wheel hub drive, thereby enabling a particularly space-saving design.Furthermore, the first coupling gear, viewed in the axial direction of the wheel hub drive, is located on the side of the rotor facing the interior of the vehicle, and specifically on a side of the wheel hub that points inwards in the axial direction of the wheel hub drive and thus towards the wheel carrier. The axial direction of the wheel hub drive runs along the machine axis of rotation or along the wheel axis of rotation, with the radial direction of the wheel hub motor being perpendicular to the axial direction of the wheel hub motor and thus perpendicular to the wheel axis of rotation or machine axis of rotation. The described arrangement of the first coupling gear allows for particularly advantageous accessibility to the coupling gear, especially in the axial direction of the wheel hub drive from the inside out, i.e., from the aforementioned side of the rotor.In particular, this allows for excellent accessibility of the coupling device as a whole, enabling particularly advantageous assembly. Furthermore, it facilitates easier maintenance and / or replacement of the coupling device.

[0015] In a further embodiment of the invention, the wheel hub drive features a brake disc that is non-rotatably connected to the wheel hub for a disc brake of the motor vehicle intended for braking the vehicle wheel. This enables particularly safe operation, since although the rotor is rotatable relative to the wheel hub when the coupling device is disengaged, the brake disc is non-rotatably connected to the wheel hub in both the disengaged and coupled states, and in particular permanently. For example, the wheel hub has a so-called brake carrier, which can be non-rotatably connected to the rim carrier. In particular, it is conceivable that the brake carrier and the rim carrier are formed integrally.In other words, the brake carrier and the wheel carrier, for example, are not constructed from separately manufactured and connected parts, but rather they are formed from a single piece, i.e., a monoblock, and are therefore integral components of an integral, and thus one-piece, manufactured body. The brake disc, for example, is connected to the brake carrier and thus to the wheel hub in a rotationally fixed manner, particularly in a reversibly detachable way.The feature that the brake disc is preferably permanently and rotationally fixed to the wheel hub means that no switching element is provided which can be switched between a locked state connecting the brake disc to the wheel hub and a release state in which the brake disc can rotate relative to the wheel hub. Rather, the brake disc is always, that is, permanently and rotationally fixed to the wheel hub. This allows for a particularly high level of safety.

[0016] In a further, particularly advantageous embodiment of the invention, at least a longitudinal region of the wheel bearing extending in the axial direction of the wheel hub drive is overlapped outwards by the rotor bearing in the radial direction of the wheel hub drive, in particular completely circumferentially in the circumferential direction of the wheel hub drive extending around the axial direction of the wheel hub drive. This allows for a particularly compact and thus space-saving design, resulting in a particularly high efficiency.

[0017] To achieve a particularly low weight for especially low-friction bearing operation and thus particularly efficient operation, the invention provides that the rotor bearing, in particular an outer ring of the rotor bearing, is supported directly on the rotor, especially on an inner circumferential surface of the rotor, in the radial direction outwards of the wheel hub drive. In the radial direction inwards of the wheel hub drive, the rotor bearing, in particular an inner ring of the rotor bearing, is supported directly on the wheel hub, especially on an outer circumferential surface of the wheel hub.

[0018] A further embodiment of the invention is characterized in that the coupling device has an actuating element, also referred to as a slider, which is displaceable in the axial direction of the wheel hub drive relative to the wheel carrier, relative to the rotor, and relative to the wheel hub between at least one coupled position that effects the coupled state and at least one uncoupled position that effects the uncoupled state. This allows for particularly efficient actuation of the coupling device, and thus a particularly efficient switching of the coupling device between the coupled state and the uncoupled state.

[0019] It has proven particularly advantageous if the coupling device includes an actuator by means of which the actuating element can be moved electrically, in particular electromagnetically, or pneumatically or hydraulically, from the coupled position to the uncoupled position and / or from the uncoupled position to the coupled position. In other words, the actuator can be operated, for example, electrically, in particular electromagnetically, pneumatically, or hydraulically. This allows the coupling device to switch between the uncoupled and coupled states particularly efficiently and according to requirements.

[0020] To achieve a particularly high efficiency, it has proven especially advantageous if power electronics, through which the electric machine can be supplied with electrical energy or current, are connected to the wheel carrier in a rotationally fixed manner. A second aspect of the invention relates to a motor vehicle, preferably designed as a motor vehicle, in particular as a passenger vehicle, 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.

[0021] Finally, it has proven particularly advantageous if the actuating element, at least in the coupled position, and especially in both the coupled and decoupling positions, passes through a corresponding through-opening in the rotor. This provides axial passage through the rotor, particularly through a rotor carrier, for the actuating element and thus for actuating the coupling device, also referred to as the decoupling device. For example, the actuating element passes through the through-opening and thus through the rotor, especially the rotor carrier, such that, at least in the coupled position, and especially in both the decoupling and coupled positions, the actuating element projects axially from the through-opening and thus from the rotor, particularly the rotor carrier, on both sides of the wheel hub drive.For example, the second coupling toothing is arranged on a side of the rotor facing away from the wheel carrier in the axial direction of the wheel hub drive, in particular on the outside.

[0022] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0023] The drawing shows in: Fig. 1 a schematic longitudinal sectional view of a first embodiment of a wheel hub drive for a motor vehicle; Fig. 2. Partially shown, a further schematic longitudinal section view of the first embodiment of the wheel hub drive; Fig. 3. Partially a schematic longitudinal section view of a second embodiment of the wheel hub drive; Fig. 4. Partially shown is another schematic longitudinal section view of the second embodiment of the wheel hub drive; Fig. 5. Partially a further schematic longitudinal section view of the second embodiment of the wheel hub drive; Fig. 6. Partially shown is another schematic longitudinal section view of the second embodiment of the wheel hub drive; Fig. 7. Partially shown is another schematic longitudinal sectional view d of the second embodiment of the wheel hub drive; and Fig. 8. Partially, a further schematic longitudinal section view of the second embodiment of the wheel hub drive.

[0024] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0025] Fig. Figure 1 shows a schematic longitudinal sectional view of a first embodiment of a wheel hub drive 10 for a motor vehicle, preferably a passenger car. In its fully manufactured state, the motor vehicle has at least or exactly two axles arranged consecutively in the longitudinal direction, and thus one behind the other. Each axle has at least or exactly two wheels, which are also simply referred to as wheels. The wheels of each axle are arranged on opposite sides of the motor vehicle in the transverse direction. One of the axles is also referred to as the first axle, and the other axle is also referred to as the second axle.The wheels of the first vehicle axle are also called the first wheels, and the wheels of the second vehicle axle are also called the second wheels. Fig. 1 is one of the vehicle wheels of one of the axles, shown schematically and labeled 12. From Fig. As can be seen from the example of the vehicle wheel 12, each vehicle wheel is a ground contact element, whereby the vehicle can be supported or is supported downwards in the vertical direction by means of the ground contact elements on a ground 14. The vehicle wheel 12 comprises a rim 16 and a tire 18, which is mounted on the rim 16. For example, the vehicle wheel 12 is the first vehicle wheel of the first axle. As will be explained in more detail below, the vehicle wheel of the first axle can be driven by means of the wheel hub drive 10. For example, the second vehicle wheel of the first vehicle axle is assigned another wheel hub drive by means of which the second vehicle wheel of the first vehicle axle can be driven. The following and preceding explanations regarding the vehicle wheel 12 and the wheel hub drive 10 can also be applied to the second vehicle wheel and the additional wheel hub drive, and vice versa.

[0026] The wheel hub drive 10 comprises a wheel carrier 20, which is articulated to a motor vehicle body, for example, a self-supporting body, by means of at least one control arm, also referred to simply as a linkage. The body defines an interior space of the motor vehicle, also referred to as the passenger compartment or passenger space, in which at least one person, such as the driver of the motor vehicle, can be located, particularly while the motor vehicle is in motion. The control arm guides the wheel carrier 20, and thus the vehicle wheel 12, to the body in such a way that excessive or undesirable relative movements between the wheel carrier 20 and the body are prevented by the control arm. In particular, the control arm allows compression and rebound movements of the wheel carrier 20 and the vehicle wheel 12, at least in the vertical direction of the vehicle and relative to the body.In particular, the wheel carrier 20, especially the wheel guide, can be supported or braced against the structure by means of at least one spring and / or damping element not shown in the figures. This suspends and / or damps the compression and rebound movements.

[0027] The wheel hub drive 10 has a wheel hub 22 which is rotatably mounted on the wheel carrier 20 via a wheel bearing 24 of the wheel hub drive 10 such that the wheel hub 22 is rotatably mounted on the wheel carrier 20 about a wheel rotation axis 26 relative to the wheel carrier 20 via the wheel bearing 24. The rim 16 is reversibly and detachably connected to the wheel hub 22 in a rotationally fixed manner, so that the vehicle wheel 12 is reversibly and detachably connected to the wheel hub 22 via the rim 16 in a rotationally fixed manner. Thus, the vehicle wheel 12, together with the wheel hub 22, can rotate about the wheel rotation axis 26 relative to the wheel carrier 20. In the embodiment shown in the figures, the wheel bearing 24 is designed as a rolling bearing, in particular as a ball bearing, which allows for a particularly low-friction mounting.

[0028] In particular, the wheel hub 22 has a rim carrier 28, wherein the vehicle wheel is connected to the rim carrier 28 and thus to the wheel hub 22 in a rotationally fixed manner, in particular reversibly detachable.

[0029] The wheel hub drive 10 also includes an electric machine 30, which has a stator 32 and a rotor 34. The rotor 34 can be driven by means of the stator 32 and is thereby rotatable about a machine axis of rotation 36 relative to the stator 32 and also relative to the wheel carrier 20. The machine axis of rotation 36 coincides with the wheel axis of rotation 26, so that when the wheel axis of rotation 26 is mentioned below, it also includes the machine axis of rotation 36, and vice versa. The rotor 34 is at least indirectly rotationally fixed to the wheel carrier 20, so that the rotor 34 and the wheel hub 22 are rotatable about the wheel axis of rotation 26 relative to the wheel carrier 20 and relative to the stator 32. For example, the stator 32 includes a stator support and at least one or more windings, which are also referred to as stator windings. The rotor 34 includes, for example, a rotor carrier 38 and magnets 40, which may in particular be designed as permanent magnets.The magnets 40 are held on the rotor carrier 38 and thus rotationally fixed to the rotor carrier 38, allowing the rotor carrier 38 to rotate about the wheel axis 26 relative to the wheel carrier 20. In the first embodiment, the rotor carrier 38, and thus the rotor 34, is rotatably mounted on the wheel hub 22 via a rotor bearing 42 provided in addition to the wheel bearing 24, so that the rotor 34 can rotate about the wheel axis 26 relative to the wheel hub 22, as will be explained in more detail below. It is evident that the rotor bearing 42 is provided in addition to the wheel bearing 24. To achieve particularly low-friction mounting and thus a particularly high efficiency, the rotor bearing 42 is designed as an additional or second rolling bearing, in particular as an additional or second ball bearing.

[0030] Furthermore, the wheel hub drive 10 has a positive-locking coupling device 44, which can be switched between a coupled state and a disengaged state. In the coupled state, the rotor 34 is positively locked and rotationally fixed to the wheel hub 22 by means of the coupling device 44, so that when the rotor 34 is driven by the stator 32 and thus rotated about the wheel axis 26 relative to the wheel carrier 20, the wheel hub 22, and thus the vehicle wheel 12, rotates with the rotor 34 about the wheel axis 26 relative to the wheel carrier 20. Therefore, if the rotor 34 is driven by the stator 32 while the coupling device 44 is in the coupled state, the wheel hub 22, and thus the vehicle wheel 12, are driven by the stator 32, in particular via the rotor 34. In other words, the vehicle wheel 12 is then driven by the electric machine 30.If the first and second vehicle wheels are electrically driven in this way by means of the wheel hub drives, the motor vehicle is thereby driven electrically, in particular purely electrically, by means of the wheel hub drives. In the decoupling state, however, the rotor 34 is rotatable about the wheel axis of rotation 26 relative to the wheel hub 22. In other words, the coupling device 44 allows relative rotations between the rotor 34 and the wheel hub 22 about the wheel axis of rotation 26 in the decoupling state. Thus, if the vehicle wheel 12 and the wheel hub 22, which is non-rotatably connected to the vehicle wheel 12, are rotated about the wheel axis of rotation 26 relative to the wheel carrier 20 while the coupling device 44 is in the decoupling state, the wheel hub 22 does not drag the rotor 34. Thus, excessive drag losses can be avoided. As shown in... Fig. As can be seen in Figure 1, the coupling device 44 has a first coupling toothing 46 that is rotationally fixed to the rotor 34 and a second coupling toothing 48 that is rotationally fixed to the wheel hub 22, in particular to the rim carrier 28. In the coupled state, the rotor 34 is positively locked and rotationally fixed to the wheel hub 22 by means of the coupling toothing 46 and 48, so that a particularly high efficiency can be achieved. For example, the first coupling toothing 46 is arranged at an end E1 of the rotor 34, in particular of the rotor carrier 38, that points inwards in the axial direction towards the wheel hub drive 10. It is also conceivable that the coupling toothing 46 is arranged on a cylindrical surface of the rotor 34, in particular of the rotor carrier 38, that points inwards or outwards in the radial direction towards the wheel hub drive 10. In particular, the end E1 can be a radially inner end of the rotor 34, especially of the rotor carrier 38.Furthermore, the end E1 is an inner end of the rotor 34, in particular of the rotor carrier 38, viewed in the axial direction of the wheel hub drive 10, so that the coupling toothing 46 is arranged on a side S of the rotor 34, in particular of the rotor carrier 38, which points inwards in the axial direction of the wheel hub drive 10 and thus faces an inner area of ​​the motor vehicle.

[0031] Furthermore, it is from Fig. 1. It is apparent that the coupling device 44 has an actuating element 50, which, as shown in Fig. As illustrated by arrows 52 in Figure 1, the coupling device 44 is displaceable in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, relative to the rotor 34, and relative to the wheel hub 22 between at least one coupled position that effects the coupling state and at least one uncoupling position that effects the decoupling state. For example, the coupling device 44 has a Fig. Figure 1 shows a particularly schematically illustrated actuator 53, which can be operated electrically, in particular electromagnetically, pneumatically or hydraulically, so that the actuating element 50 can be moved electrically, in particular electromagnetically, pneumatically or hydraulically, from the coupled position to the decoupling position and / or from the decoupling position to the coupled position. This allows the coupling device 44 to be switched between the coupled state and the decoupling state particularly efficiently and as required.

[0032] The wheel hub drive 10 further comprises a disc brake 54, which is a service brake of the motor vehicle and is designed to brake the wheel hub 22 and thus the vehicle wheel 12 and thus the motor vehicle as a whole. The disc brake 54 comprises a brake caliper 56, which is non-rotatably connected to the wheel carrier 20. The disc brake 54 also comprises a brake disc 58, which is, in particular, permanently non-rotatably connected to the wheel hub 22. For this purpose, the wheel hub 22 includes, for example, a brake carrier 60, which is, for example, permanently non-rotatably connected to the rim carrier 28. The brake disc 58 is thereby non-rotatably connected to the brake carrier 60 and thus to the wheel hub 22.The brake disc 58 is rotationally fixed to the wheel hub 22 in both the decoupling and coupled states, so that the wheel hub 22 and thus the vehicle wheel 12 can be braked by means of the disc brake 54 in both the decoupling and coupled states, in particular with regard to a rotation about the wheel axis 26 relative to the wheel carrier 20.

[0033] Out of Fig. Figure 1 also clearly shows that at least a longitudinal region L1 of the wheel bearing 24 extending in the axial direction of the wheel hub drive 10 is completely overlapped, i.e., covered, by the rotor bearing 42 in the radial direction of the wheel hub drive 10 towards the outside, thus resulting in a particularly compact and efficient design. Furthermore, it can be seen that the rotor bearing 42 is supported directly on the rotor 34, in particular on the rotor carrier 38, in the radial direction of the wheel hub drive 10 towards the outside, and directly on the wheel hub 22, in particular on the rim carrier 28, in the radial direction of the wheel hub drive 10 towards the inside.

[0034] In the embodiments shown in the figures, the wheel hub drive 10 also optionally includes power electronics 62, via which the electric machine 30 can be supplied with electrical energy, in particular electric current. Optionally, the power electronics 62 is rotationally fixed to the wheel carrier 20. Fig. As can be seen in Figure 1, the power electronics 62, for example, is at least partially, and in particular at least predominantly and thus at least more than halfway or completely, covered by the wheel hub 22, especially by the brake carrier 60, in the radial direction of the wheel hub drive 10. Viewed in the axial direction of the wheel hub drive 10 and thus along the wheel axis of rotation 26, the brake disc 58, the power electronics 62, and the stator 32 are arranged, for example, in the following order, viewed from the inside out: the brake disc 58, the power electronics 62, and the stator 32. To switch the coupling device 44 from its decoupling state to its coupling state, i.e., to close it, the actuating element 50 is moved outwards in the axial direction of the wheel hub drive 10.For example, to switch the coupling device 44 from its coupled state to its uncoupled state and thus open it, the actuating element 50 is moved inwards in the axial direction of the wheel hub drive 10. The coupled state is also referred to as the closed state, while the uncoupled state is also referred to as the open state.

[0035] Out of Fig. 2. It can be seen that the stator 32, for example, is formed separately from the wheel carrier 20 and is connected to the wheel carrier 20 by means of at least one stator screw 64 and is thus rotationally fixed to the wheel carrier 20. The brake carrier 60 has, for example, a lamellar toothing by means of which the brake carrier 60 is rotationally fixed to the brake disc 58. The lamellar toothing is also referred to as the first lamellar toothing. For example, the brake disc 58 has a second lamellar toothing corresponding to the first lamellar toothing, wherein the lamellar toothing is connected to each other, in particular rotationally fixed and / or positively locking, so that the brake carrier 60 is rotationally fixed, in particular positively locking, to the brake disc 58 by means of the lamellar toothing and vice versa. For example, the actuating element 50 is a release bearing and is also referred to as a release bearing. Fig. 2 A release bearing 66, also referred to simply as a bearing, is discernible, by means of which the release mechanism (actuating element 50) is mounted, in particular rotatably, on the wheel carrier 20, but in such a way that the release mechanism can be axially displaced as described. In particular, linear actuation of the release mechanism and thus of the coupling device 44 can be represented by a rotary movement of the release mechanism. For this purpose, the actuator is shown, for example, as a rotary actuator. In other words, the actuating element 50 can, for example, be rotated by means of the actuator, in particular relative to the wheel carrier 20, whereby a translational movement and thus displacement of the actuating element 50 in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, relative to the wheel hub 22 and relative to the rotor 34 can be effected or is effected.For this purpose, the rotation of the release mechanism relative to the wheel carrier 20, caused or achievable by the actuator, is converted into a displacement of the release mechanism in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20. This displacement of the release mechanism closes, for example, the initially opened coupling device 44 and / or vice versa.

[0036] For example, a speed decoupling of the actuating element 50 is provided. Speed ​​decoupling can be understood in particular as follows: The actuating element 50 has, for example, at least or exactly two actuating parts, namely a first actuating part and a second actuating part. The first actuating part is, for example, rotationally fixed to the wheel carrier 20, thus held on the wheel carrier 20 in such a way that relative rotations about the wheel axis of rotation 26 between the first actuating part and the wheel carrier 20 are prevented. For example, the first actuating part is the aforementioned release bearing. The second actuating part is, for example, a sliding sleeve. The second actuating part is, for example, rotationally fixed to the rotor 34, thus rotating with the rotor 34 about the wheel axis of rotation 26 relative to the wheel carrier 20 and therefore also relative to the first actuating part.The actuating elements are thus rotatable relative to each other about the wheel axis of rotation 26, but are coupled to each other, particularly in the axial direction of the wheel hub drive 10, such that a displacement of the first actuating element in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, relative to the wheel hub 22, and relative to the rotor 34 results in a displacement of the second actuating element in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, relative to the wheel hub 22, and relative to the rotor 34. Thus, for example, the actuator can be easily and, in particular, rotationally fixed to the wheel carrier 20.If the actuator moves the first actuating element axially along the wheel hub drive 10 relative to the wheel carrier 20, the wheel hub 22, and the rotor 34, this movement causes the second actuating element to move axially along the wheel hub drive 10 relative to the wheel carrier 20, the rotor 34, and the wheel hub 22. This movement shifts the actuating elements, and thus the actuating element 50, axially along the wheel hub drive 10 between the disengaged and engaged positions, enabling the coupling device 44 to switch between these positions as needed. The brake carrier 60 and the wheel hub 22, for example, each have a hub 68 with a drive tooth or drive teeth.

[0037] In particular, the mounting of the rotor 34 via the rotor bearing 42 on the wheel hub 22, especially on the brake carrier 60, allows the coupling device 44, preferably designed as a claw coupling, to be arranged on one side of the rotor 34 of the vehicle, i.e. on the side S of the rotor 34 which points inwards in the axial direction of the wheel hub drive 10 and thus faces the interior of the motor vehicle, making the coupling device 44 particularly accessible for the actuator, also referred to as actuation, from side S. Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows a second embodiment of the wheel hub drive 10. The one in Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. The second embodiment shown in Figure 8 is not part of the invention. The second embodiment differs from the first embodiment in particular in that, in the second embodiment, the rotor 34, and thus the rotor carrier 38, is rotatably mounted on the wheel carrier 20 via the rotor bearing 42. Thus, for example, the rotor bearing 42 is supported directly on the rotor 34, and in particular on the rotor carrier 38, in the radial direction outwards of the wheel hub drive 10, and, for example, the rotor bearing 42 is supported directly on an inner circumferential surface of the rotor 34, and in particular on the rotor carrier 38, in the radial direction outwards of the axle drive 10. In the radial direction inwards of the wheel hub drive 10, the rotor bearing 42 is supported directly on the wheel carrier 20, and in particular on an outer circumferential surface of the wheel carrier 20.However, the following descriptions of the second embodiment, particularly with regard to the actuating element 50 and the coupling device 44, and especially with regard to their actuating, can be transferred to the first embodiment.

[0038] Out of Fig. In Figure 3, the stator 32 and the rotor 34 with the rotor carrier 38 and the magnets 40 are particularly clearly visible. It is evident that the stator 32 is at least partially overlapped by the stator 32 in the radial direction of the wheel hub drive 10 towards the outside. This is particularly evident from... Fig. 3 it is evident that the, for example, sliding sleeve and in Fig. The second actuating element, designated 3 with 70, extends through the rotor carrier 38 and, for example, has a claw which, in the coupled state, interacts with the corresponding second coupling toothing 48 of the wheel hub 22. Furthermore, the claw interacts, for example, at least in the coupled position or in the coupled state, and in particular in both the coupled and uncoupled states, with the corresponding first coupling toothing 46 of the rotor 34, so that in the coupled state the rotor 34 is positively locked and rotationally fixed to the wheel hub 22 by means of the claw and the coupling teeth 46 and 48, or vice versa. The in Fig. The first actuating element 72, designated as such and designed, for example, as a release element, is held on the wheel carrier 20 so as to be displaceable in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, as illustrated by arrow 52. For example, the actuating element 70 rotates with the rotor 34 in both the coupled and the disengaged states. The aforementioned rotational decoupling includes, for example, rolling elements 74, which allow relative rotations between the actuating elements 70 and 72 about the wheel axis of rotation 26, but couple the actuating elements 70 and 72 to each other in such a way that the actuating element 70 can be displaced by displacing the actuating element 72.This allows the actuating parts 70 and 72, and thus the actuating element 50, to be actuated linearly, i.e. in the axial direction of the wheel hub drive 10, in particular relative to the wheel carrier 20, i.e., to be moved, so that they rotate about the wheel axis 26 relative to each other.

[0039] Fig. Figure 4 shows the coupling device 44 in the Fig. 4 coupling state designated K, such that the coupling device 44, also referred to as a coupling, is closed. For example, the actuating element 50 or the actuating part 70 is designed as a claw, in particular as a claw ring. Fig. Figure 5 shows the coupling device 44 in the decoupling state designated E. Fig. Figure 6 shows the actuating element 50 in the coupling position KS, so that the coupling device 44 is in the coupled state. Fig. Figure 7 shows the actuating element 50 in the decoupling position ES, so that the coupling device 44 is in the decoupling state.

[0040] Finally, it shows Fig. 8 the wheel hub drive 10 partially shown in a further schematic longitudinal section view. From Fig. Figure 8 shows that the actuating parts 70 and 72, and thus the actuating element 50, are displaceable in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, relative to the rotor 34, and relative to the wheel hub 22 such that the actuating part 72 has a first toothing Z1. For this purpose, the actuating part 72 is designed, for example, as a first rack. The actuator 53 has, for example, a gear 75 which is rotatable about an axis of rotation relative to the wheel carrier 20. The axis of rotation runs, for example, perpendicular to the axial direction of the wheel hub drive 10. The gear 75 has a second toothing Z2 corresponding to the toothing Z1, which engages with the corresponding toothing Z1. As in Fig. As illustrated by a double arrow 76 in Figure 8, when the gear 75 is rotated back and forth, the actuating element 72 and, via this, the actuating element 70 are moved back and forth in the axial direction of the wheel hub drive 10 relative to the wheel carrier 20, thereby allowing the actuating element 50 to be moved between the decoupling position ES and the coupling position KS. For example, the actuator 53 includes an electric motor by means of which the gear 75 can be rotated back and forth as required. This allows the coupling device 44 to be switched between the coupling state and the decoupling state as required. For example, the rolling elements 74 are rolling elements of a deep groove ball bearing, by which the rotational decoupling is represented.

[0041] At the in Fig.In the embodiment shown in Figure 8, the actuator 53 is designed as a rotary actuator, in particular as an electric rotary actuator. It would also be conceivable that the actuator 53 is a linear actuator whose rotor is not rotatable relative to the wheel carrier 20, but rather displaceable relative to the wheel carrier 20. Furthermore, it would be conceivable that the actuator 53 has a piston, or is a piston, which is, for example, translationally displaceable relative to the wheel carrier 20 in order to move, and thus displace, the actuating element 50 translationally.

Claims

[1] Wheel hub drive (10) for a motor vehicle, comprising a wheel carrier (20), a wheel hub (22) rotatably mounted on the wheel carrier (20) via a wheel bearing (24), to which a vehicle wheel (12) of the motor vehicle can be connected in a rotationally fixed manner, an electric machine (30) comprising a stator (32) rotationally fixed to the wheel carrier (20) and a rotor (34) which can be driven by means of the stator (32) and is thereby rotatable relative to the stator (32), and which is rotatably mounted on the wheel hub (22) via a rotor bearing (42), and a positive-locking coupling device (44) which is switchable between a coupling state (K), in which the rotor (34) is positively and rotationally fixedly connected to the wheel hub (22) by means of the coupling device (44), and a decoupling state (E), in which the rotor (34) is rotatable relative to the wheel hub. (22) is rotatable,wherein the rotor bearing (42) is supported in the radial direction of the wheel hub drive (10) directly on the rotor (34) towards the outside and in the radial direction of the wheel hub drive (10) directly on the wheel hub (22). [2] Wheel hub drive (10) according to claim 1, characterized by , that the coupling device (44) has a first coupling toothing (46) connected to the rotor (34) in a rotationally fixed manner and a second coupling toothing (48) connected to the wheel hub (22) in a rotationally fixed manner, wherein in the coupling state (K) the rotor (34) is connected to the wheel hub (22) by means of the coupling teeth (46, 48) in a positively locking manner. [3] Wheel hub drive (10) according to claim 2, characterized by , that the first coupling toothing (46) is arranged at a radially inner end (E1) and axially on a side (S) of the rotor (34) facing an interior area of ​​the motor vehicle. [4] Wheel hub drive (10) according to any one of the preceding claims, characterized bya disc brake (54) for braking the vehicle wheel (12) with a brake disc (58) connected to the wheel hub (22) in a rotationally fixed manner. [5] Wheel hub drive (10) according to any one of the preceding claims, characterized by , that at least a length region (L1) of the wheel bearing (24) extending in the axial direction of the wheel hub drive (10) is overlapped outwards in the radial direction of the wheel hub drive (10) by the rotor bearing (42). [6] Wheel hub drive (10) according to any one of the preceding claims, characterized by , that the coupling device (44) has an actuating element (50) which is displaceable in the axial direction of the wheel hub drive (10) relative to the wheel carrier (20), relative to the rotor (34) and relative to the wheel hub (22) between at least one coupling position (KS) that effects the coupling state (K) and at least one decoupling position (ES) that effects the decoupling state (E). [7] Wheel hub drive (10) according to claim 6, characterized by, that the coupling device (44) has an actuator (53) by means of which the actuating element (50) can be moved electromagnetically or pneumatically or hydraulically from the coupling position (K) to the decoupling position (ES) and / or from the decoupling position (ES) to the coupling position (KS). [8] Wheel hub drive (10) according to any one of the preceding claims, characterized by , that a power electronics (62), via which the electric machine (30) can be supplied with electrical energy, is connected to the wheel carrier (20) in a rotationally fixed manner.

Images