Shiftable wheel hub

Abstract

The invention relates to a shiftable wheel hub (1) for a vehicle, comprising - a carrier (2), on which a rim of a wheel can be mounted, - a side shaft (3), which is designed to drive the carrier (2) and can be driven by a drive unit of the vehicle, - a planetary transmission (6), which has planetary gears (7) in engagement with the carrier (2), and a ring gear (8), which meshes with the planetary gears (7), - a restoring spring (11) for restoring the wheel hub (1) into a normal position (NoP) in which the carrier (2) is in direct engagement with the side shaft (3), - a shift actuator for moving the wheel hub (1) into a crawler position (CP) in which the carrier (2) is in engagement with the side shaft (3) via the planetary transmission (6), the side shaft (3) being displaceable along a longitudinal axis (L) with respect to the carrier (2) by means of the shift actuator, wherein a claw (4) for joint rotation and displacement along the longitudinal axis (L) with the side shaft (3) is arranged on the side shaft (3), said claw (4), in the normal position (NoP), being in engagement with the carrier (2) and forming a first coupling point (5), the ring gear (8) being displaceable together with the side shaft (3) and, with a hub (9), forming a second coupling point (10) which, in the crawler position (CP), is in engagement with the side shaft (3), with the restoring spring (11) being arranged between the carrier (2) and the side shaft (3).

Description

[0001] Daimler Truck AG Özvatan

[0002] August 26, 2025

[0003] Switchable wheel hub

[0004] The invention relates to a switchable wheel hub for a vehicle according to the preamble of claim 1 and to a vehicle according to the preamble of claim 4.

[0005] The prior art includes increasing gear ratios and using electric motors with higher torques at lower speeds. Higher speed ratios result in higher losses. Furthermore, higher speed ratios limit the optimal system design for a given application (optimal operating point).

[0006] DE 102021 203 043 A1 describes a switchable wheel hub transmission for a motor vehicle, comprising a planetary gear set, wherein the planetary gear set has a ring gear with internal teeth, a central sun gear with external teeth arranged concentrically and rotatably within the ring gear, a rotatably mounted planet carrier, and at least one planet gear with external teeth rotatably mounted on the planet carrier, wherein the planet gear set is arranged between the ring gear and the sun gear set, and the external teeth of the planet gear engage with the internal teeth of the ring gear and with the external teeth of the sun gear set, wherein the ring gear set is axially movable in two switching positions, namely a first switching position and a second switching position. Furthermore, a drive system with at least two such switchable wheel hub transmissions and at least two electric machines is described.

[0007] EP 4 047242 A1 describes a wheel hub comprising a housing and a reduction gear. The reduction system includes a planetary gear configured for operational connection between the axle and the wheel, a bushing for sliding connection to the axle, and an actuating device for moving the bushing. The reduction system has a first operating position in which the bushing engages with the planetary gear to transmit drive power from the axle at a first speed ratio, and a second operating position in which the bushing disengages from the planetary gear and engages with the end cap of the housing to transmit drive power from the axle at a second speed ratio of 1:1.

[0008] The invention is based on the objective of specifying a novel switchable wheel hub for a vehicle as well as a novel vehicle.

[0009] The problem is solved according to the invention by a switchable wheel hub for a vehicle with the features of claim 1 and a vehicle with the features of claim 4.

[0010] Advantageous embodiments of the invention are the subject of the dependent claims.

[0011] A switchable wheel hub for a vehicle is proposed, comprising

[0012] - a carrier on which a wheel rim can be mounted,

[0013] - a side shaft designed to drive the carrier and which can be driven by a drive unit of the vehicle,

[0014] - a planetary gear system comprising planet gears engaged with the carrier and a ring gear meshing with the planet gears,

[0015] - a return spring to return the wheel hub to a normal position in which the carrier is in direct engagement with the side shaft,

[0016] - a switching actuator for adjusting the wheel hub into a crawler position in which the carrier is engaged with the side shaft via the planetary gear.

[0017] According to the invention, the side shaft is displaceable along a longitudinal axis relative to the carrier by means of the switching actuator, wherein a claw for joint rotation and displacement along the longitudinal axis with the side shaft is arranged on the side shaft, which is in engagement with the carrier in the normal position and forms a first coupling point, wherein the ring gear is displaceable together with the side shaft and forms a second coupling point with a hub, which is in engagement with the side shaft in the crawler position, wherein the return spring is arranged between the carrier and the side shaft.

[0018] Instead of coupling the side shaft to the carrier, coupling the ring gear to the carrier is also possible. In this solution, the torque is always transmitted via the planet carrier, forming a coupling structure. A third solution is also possible: coupling the side shaft to the ring gear.

[0019] The present invention proposes the use of switchable wheel hubs as crawlers to enable starting and maneuvering under difficult conditions (for example, crossing curbs, extreme inclines). The activation and deactivation of the switchable wheel hub occurs, for example, only when stationary, without increased control complexity (speed sensing, separate actuators, etc.).

[0020] The solution according to the invention allows the maximum starting torque to be increased in electric motor vehicle drives.

[0021] The solution according to the invention provides a simple system for increasing performance data without complex control or regulation, since switching occurs particularly when the system is stationary. The system can be returned to its safe basic state by spring force without any actuation and / or signal.

[0022] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0023] This shows:

[0024] Fig. 1: a schematic view of a switchable wheel hub in a normal position,

[0025] Fig. 2: a schematic view of the switchable wheel hub in a neutral position, and

[0026] Fig. 3: a schematic view of the switchable wheel hub in a crawler position.

[0027] Corresponding parts are marked with the same reference symbols in all figures.

[0028] Figure 1 is a schematic view of a switchable wheel hub 1 for a vehicle, in particular a commercial vehicle, a bus or a passenger car. For example, the vehicle can have one such wheel hub 1 on each of at least one axle of the vehicle, on the left and right sides.

[0029] The wheel hub 1 has a carrier 2 to which a wheel rim (not shown) can be mounted. The wheel hub 1 also has a side shaft 3, which is designed to drive the carrier 2 and can itself be driven by a drive unit (not shown) of the vehicle. The side shaft 3 has a longitudinal axis L along which it is displaceable relative to the carrier 2. A claw 4 is arranged on the side shaft 3 for rotation and displacement along the longitudinal axis L with the side shaft 3. In a normal position NoP of the side shaft 3 shown in Figure 1, the claw 4 engages with the carrier 2 via a first coupling point 5 and thus couples it for rotation with the side shaft 3. The wheel hub 1 also has a planetary gear 6, which has planet gears 7 that engage with the carrier 2.The planetary gear 6 further comprises a ring gear 8, which meshes with the planet gears 7 and is displaceable together with the side shaft 3. The planetary gear 6 also comprises a sun gear 12, which meshes with the planet gears 7 and is displaceable together with the side shaft 3. The sun gear 12 can be fixed to the side shaft 3 to prevent rotation and can carry the claw 4. The ring gear 8 forms a second coupling point 10 with a hub 9, which, however, is open and not engaged in the normal position NoP shown in Figure 1. In the normal position NoP, the sun gear 12 is directly coupled to the carrier 2 or output via the first coupling point 5. Thus, the sun gear 12 is also coupled to the carrier 2 and rotates as a unit. The second coupling point 10 must not be engaged in the normal position NoP, as this would otherwise create a parking lock. Furthermore, a return spring 11 is arranged to return the side shaft 3 to the normal position NoP.The return spring 11 is, for example, arranged between the carrier 2 and the side shaft 3.

[0030] Furthermore, a sliding sleeve 13 (axial, but not rotationally fixed connection) is arranged.

[0031] A switching actuator (not shown) is provided for shifting the side shaft 3 from its normal position NoP. If there are two switchable wheel hubs 1 on the left and right sides of the same axle of the vehicle, a common switching actuator can be provided for both side shafts 3.

[0032] Figure 2 is a schematic view of the switchable wheel hub 1, where the side shaft 3 has been moved from its normal position NoP to a neutral position NeP by means of the switching actuator against the force of the return spring 11. The first coupling point 5 is open, and the claw 4 is therefore no longer engaged with the carrier 2. The second coupling point 10 remains open, and the hub 9 is therefore not engaged with the ring gear 8. Thus, no torque is transmitted between the side shaft 3 and the carrier 2. In this position, synchronization of the gear ratio can take place. The desired switching state can be set by accelerating the sun gear 12 until the ring gear 8 comes to a standstill or by adjusting the speed synchronization between the sun gear 12 and the carrier 2.

[0033] Figure 3 is a schematic view of the switchable wheel hub 1, where the side shaft 3 has been moved from the neutral position NeP into a crawler position CP by means of the switching actuator against the force of the return spring 11. The first coupling point 5 remains open, and the claw 4 is therefore not engaged with the carrier 2. The second coupling point 10 is closed by the displacement of the ring gear 8, and the hub 9 is thus engaged with the ring gear 8. A torque is therefore transmitted between the side shaft 3 and the carrier 2 via the planetary gear 6. In this way, a reduction gear can be achieved.

[0034] The switchable wheel hub 1 can be designed, in particular, for shifting only when stationary or at low speeds.

[0035] The return spring 11 allows the side shaft 3 to automatically return from the crawler position CP to the normal position NoP in a simple manner or with reduced control effort, without requiring speed sensing or determining the switching position. This ensures a reliable normal position NoP or initial position (normally off). In this position, the wheel hub 1 can be operated across the entire speed profile under normal conditions.

[0036] The crawler position CP, on the other hand, is actively initiated by the switching actuator. The switching actuator can be implemented very simply, for example as a pneumatic cylinder.

[0037] Daimler Truck AG Özvatan

[0038] August 26, 2025

[0039] Reference symbol list

[0040] 1 wheel hub

[0041] 2 carriers

[0042] 3 Side shaft

[0043] 4 Claw

[0044] 5 coupling point

[0045] 6 planetary gears

[0046] 7 planetary gears

[0047] 8 Ring gear

[0048] 9 hub

[0049] 10 coupling point

[0050] 11 Return spring

[0051] 12 sun wheel

[0052] 13 sliding sleeve

[0053] CP Crawler Position

[0054] L Longitudinal axis

[0055] NeP Neutral position

[0056] NoP Normal position

Claims

Daimler Truck AG Özvatan August 26, 2025 Patent claims 1. Switchable wheel hub (1) for a vehicle, comprising - a carrier (2) on which a wheel rim can be mounted, - a side shaft (3) designed to drive the carrier (2) and which can be driven by a drive unit of the vehicle, - a planetary gear (6) comprising planet gears (7) engaged with the carrier (2) and a ring gear (8) meshing with the planet gears (7), - a return spring (11) for returning the wheel hub (1) to a normal position (NoP) in which the carrier (2) is in direct engagement with the side shaft (3), - a switching actuator for adjusting the wheel hub (1) into a crawler position (CP) in which the carrier (2) is engaged with the side shaft (3) via the planetary gear (6), characterized in that the side shaft (3) is displaceable along a longitudinal axis (L) relative to the carrier (2) by means of the switching actuator, wherein a claw (4) for common rotation and displacement along the longitudinal axis (L) with the side shaft (3) is arranged on the side shaft (3) or on the ring gear (8), which in the normal position (NoP) is engaged with the carrier (2) and forms a first coupling point (5), or wherein a claw (4) for common rotation and displacement along the longitudinal axis (L) with the side shaft (3) is arranged on the side shaft (3), which in the normal position (NoP) is engaged with the ring gear (8) and forms a first coupling point (5),wherein the ring gear (8) is displaceable together with the side shaft (3) and forms a second coupling point (10) with a hub (9) which is engaged with the side shaft (3) in the crawler position (CP), wherein the return spring (11) is arranged between the carrier (2) and the side shaft (3).

2. Switchable wheel hub (1) according to claim 1, characterized in that the side shaft (3) further has a neutral position (NeP) between the normal position (NoP) and the crawler position (CP), wherein the first coupling point (5) and the second coupling point (10) are open and not engaged in the neutral position (NeP).

3. Switchable wheel hub (1) according to claim 1 or 2, characterized in that the switching actuator is designed as a pneumatic cylinder.

4. Vehicle comprising at least one axle with a switchable wheel hub (1) on a left and a right side of the axle, characterized in that the switchable wheel hubs (1) are designed according to one of the preceding claims.

5. Vehicle according to claim 4, characterized in that a common switching actuator is arranged for both switchable wheel hubs (1) of the same axle.

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