Control device and traction control method for a first wheel of a vehicle axle additionally equipped with a second wheel.

Abstract

The invention provides a control device (14) and a traction control method for a first wheel (16a) of a vehicle axle (18) of a vehicle (10) additionally equipped with a second wheel (16b), wherein, during the driving of the vehicle axle (18) by means of at least one motor (12) of the vehicle (10), the following process steps are carried out alternately: braking of the first wheel (16a) by means of a wheel-individual electromechanical brake module (26a) for a predetermined or fixed first time interval such that the wheel speed of the first wheel (16a) is reduced and maintained below a predetermined maximum wheel speed value during the first time interval, and interruption of the braking exerted on the first wheel (16a) by means of the wheel-individual electromechanical brake module (26a) for the first time interval for a predetermined or fixed second time interval such thatthat a braking torque applied to the first wheel (16a) by means of the wheel-individual electromechanical brake module (26a) is reduced and maintained below a predetermined maximum braking torque value during the second time interval.

Description

[0001] The present invention relates to a control device for a vehicle having a vehicle axle equipped with two wheels. The invention also relates to a parking brake module. Furthermore, the invention relates to a traction control method for a first wheel of a vehicle axle additionally equipped with a second wheel, and to a method for driving a vehicle axle equipped with two wheels. State of the art

[0002] An e-axle module for an electrically powered vehicle is known from the prior art, such as DE 10 2021 214 867 A1. The respective e-axle module comprises an electric drive motor and an associated eddy-current brake. However, when the electrically powered vehicle is equipped with the e-axle module, a wheel-specific service brake, which allows a relatively high braking torque to be applied to a specific wheel of the vehicle, even for a comparatively long braking time, without significant heating of the respective service brake, is usually omitted. Disclosure of the invention

[0003] The present invention provides a control device for a vehicle having a vehicle axle equipped with two wheels, with the features of claim 1, a parking brake module with the features of claim 7, a traction control method for a first wheel of a vehicle axle additionally equipped with a second wheel, with the features of claim 8, and a method for driving a vehicle axle equipped with two wheels, with the features of claim 10. Advantages of the invention

[0004] The present invention provides advantageous possibilities for driving or accelerating a vehicle, particularly on a road surface with one side slippery and a significant incline, using a wheel-specific electromechanical brake module that is smaller and / or less resilient than conventional wheel-specific service brakes. The respective wheel-specific electromechanical brake module can be used by means of the present invention instead of conventional wheel-specific service brakes for traction control (TCS, Traction Control System) or for the EDL function (Electronic Differential Lock Function). It is expressly pointed out that the respective wheel-specific electromechanical brake module can be a relatively space-saving, comparatively cost-effective, and relatively simply designed electromechanical actuator, which acts, for example, on a multi-disk brake package.The present invention thus contributes to making it easier to dispense with the need to equip a vehicle with conventional wheel-specific service brakes. The present invention particularly contributes to the realization of novel vehicle topologies in which conventional wheel-specific service brakes are dispensed with and instead a service brake is installed centrally in the drivetrain. The service brake integrated centrally in the drivetrain can, for example, be an eddy current brake, which is why this advantageous brake type can be used more frequently thanks to the present invention.

[0005] In an advantageous embodiment of the control device, the electronic device is designed and / or programmed to carry out the traction control for the first wheel, provided that it is at least specified as information by means of the electronic device or provided to the electronic device that a measured or estimated first variable with respect to a first coefficient of friction of a road surface contacted by the first wheel is below a predetermined minimum value, a difference between the first variable and a measured or estimated second variable with respect to a higher second coefficient of friction of another road surface contacted by a second wheel of the two wheels is above a predetermined maximum difference and / or a measured or estimated gradient of a road surface traveled by the vehicle is above a predetermined limit gradient.The present invention can therefore also be used in particular as an operating strategy for µ-split acceleration processes on significant gradients.

[0006] Alternatively or additionally, the electronic device can also be designed and / or programmed to carry out the traction control for the first wheel, provided that at least one measured or estimated temperature present at the wheel-specific electromechanical brake module during the driving of the vehicle axle by means of the at least one motor while simultaneously braking the first wheel by means of a predetermined or fixed braking torque of the wheel-specific electromechanical brake module exceeds a predetermined limit temperature.Since the traction control for the first wheel, which can be executed by means of the control device / its electronic device, is associated with (essentially) no thermal load on the wheel-specific electromechanical brake module, the traction control for the first wheel can be used specifically when further driving of the vehicle axle by means of the at least one motor while simultaneously braking the first wheel using the predefined or fixed braking torque of the wheel-specific electromechanical brake module would be associated with a high risk of overheating of the wheel-specific electromechanical brake module. This contributes to improved protection of the wheel-specific electromechanical brake module and increases its service life, even when it is used (in conjunction) to execute a TC function (Traction Control Function) or an EDL function (Electronic Differential Lock Function).

[0007] In a further advantageous embodiment of the control device, a parking brake module can be operated by means of the electronic device as a wheel-individual electromechanical brake module alternately for the first time interval in the first mode and for the second time interval in the second mode. The parking brake module can be understood in particular as a dedicated, miniaturized, and cost-effective parking brake actuator whose thermal load capacity is limited. Although a parking brake module, or a parking brake, is typically only designed for static load cases in which no or hardly any friction work occurs, the parking brake module can be thermally controlled in such an optimal manner by means of the traction control implemented by the control device / electronic device that the friction work generated by the parking brake module is minimized and therefore there is generally no risk of overheating of the parking brake module.The present invention thus contributes to improving the functionality of the parking brake module, particularly on a vehicle without conventional wheel-individual service brakes.

[0008] In particular, by means of the electronic device as a wheel-specific electromechanical brake module, a parking brake module mounted on a differential output of the first wheel can be operated alternately in the first mode for the first time interval and in the second mode for the second time interval. The embodiment of the control device described here is therefore particularly advantageous for use on a vehicle with a reduced-size parking brake module located at the differential output, which, in addition to meeting the required specifications of a parking brake, can also contribute to fulfilling a TC (Traction Control Function) or an EDL (Electronic Differential Lock Function) function.

[0009] The control device can, for example, be a central vehicle control unit. The advantageous design of the control device / its electronic device for traction control for the first wheel can thus be integrated with a multitude of other control functions into a device frequently used in the vehicle.

[0010] The advantages described above are also realized in a parking brake module with such a control device. It is expressly pointed out that the parking brake module can be understood as a dedicated, miniaturized, and cost-effective parking brake actuator or a corresponding parking brake. Even if the thermal load capacity of the parking brake module is limited, the fact that the parking brake module is equipped with the control device ensures a reduction in the thermal load on the brake discs of the parking brake module or on the base brake used for the parking brake module by executing traction control for the first wheel.

[0011] Likewise, implementing a corresponding traction control method for a first wheel of a vehicle axle additionally equipped with a second wheel also realizes the advantages described above. In particular, the first wheel can be completely locked during the first time interval by means of the wheel-specific electromechanical braking module, so that the wheel speed of the first wheel is reduced to zero and maintained during the first time interval, while the wheel lock exerted on the wheel by means of the wheel-specific electromechanical braking module during the first time interval is released during the second time interval, so that the braking torque exerted on the first wheel by means of the wheel-specific electromechanical braking module is reduced to zero and maintained during the second time interval.

[0012] Furthermore, implementing a corresponding method for driving a vehicle axle equipped with two wheels also provides the advantages listed above. It is expressly noted that the traction control method and the driving method can be further developed according to the embodiments of the control device explained above. Short description of the drawings

[0013] Further features and advantages of the present invention are explained below with reference to the figures. They show: Fig. 1a and Fig. 1b Coordinate systems for explaining an embodiment of the traction control method for a first wheel of a vehicle axle of a vehicle additionally equipped with a second wheel; Fig. 2 is a flowchart for explaining an embodiment of the method for driving a vehicle axle of a vehicle equipped with two wheels; and Fig. 3 a schematic representation of a vehicle with a vehicle axle equipped with two wheels for explaining an embodiment of the control device. Embodiments of the invention

[0014] Fig. 1a and Fig. 1b show coordinate systems for explaining an embodiment of the traction control method for a first wheel of a vehicle axle of a vehicle additionally equipped with a second wheel.

[0015] The traction control method described below can be implemented with (almost) all vehicle types / motor vehicle types with central axle drive of the vehicle axle equipped with the first wheel and the second wheel. Preferably, the driven vehicle axle equipped with the first wheel and the second wheel is a rear axle of the vehicle / motor vehicle. Alternatively, however, the driven vehicle axle equipped with the first wheel and the second wheel can also be a front axle of the vehicle / motor vehicle. The vehicle / motor vehicle can, in particular, be an electric or hybrid vehicle, but also a vehicle / motor vehicle equipped with an internal combustion engine.Although the traction control method described below is preferably carried out on a vehicle / motor vehicle without a conventional wheel-individual service brake for exerting a comparatively high braking force for a relatively long time on the respective assigned wheel, which is designed for high thermal stress, its executability is not limited to this vehicle type / motor vehicle type.

[0016] Preferably, the traction control method described below is executed for the first wheel if a measured or estimated first variable relating to a first coefficient of friction of a road surface contacted by the first wheel is below a predetermined minimum value and / or a difference between the first variable and a measured or estimated second variable relating to a higher second coefficient of friction of another road surface contacted by the second wheel is above a predetermined maximum difference. It is particularly advantageous to execute the traction control method even if (additionally) a measured or estimated gradient of a road surface traveled by the vehicle is above a predetermined limit gradient.The traction control method can thus be advantageously implemented especially for drive and acceleration processes on a µ-split gradient, which are particularly safety-relevant due to the inherent risk of the vehicle rolling back. However, the implementation of the traction control method described below is not limited to this specific case.

[0017] When executing the traction control method, method steps S1 and S2 are carried out alternately while the vehicle axle (equipped with the first and second wheels) is driven by at least one motor of the vehicle. The at least one motor used to drive the vehicle axle can, in particular, be at least one electric drive motor installed centrally in the drive train of the vehicle and / or at least one internal combustion engine mounted centrally in the drive train. When executing method step S1, the first wheel is braked by means of a wheel-specific electromechanical brake module for a predetermined or fixed first time interval Δ1 such that a wheel speed / wheel rotational speed ω1 of the first wheel during the first time interval Δ1 remains below a predetermined maximum wheel speed / wheel rotational speed ω 10reduced and maintained. In contrast, in method step S2, the braking applied to the first wheel by means of the wheel-specific electromechanical brake module for the first time interval Δ1 is interrupted for a predetermined or fixed second time interval Δ2 such that a braking torque M1 applied to the first wheel by means of the wheel-specific electromechanical brake module during the second time interval Δ2 is reduced and maintained below a predetermined maximum braking torque value. The alternating execution of method steps S1 and S2 is in the coordinate system of the Fig. 1a, the abscissa of which is a time axis t and the ordinate of which is the (normalized) braking torque M1 exerted on the first wheel by means of the wheel-individual electromechanical braking module.

[0018] A friction work W exerted on the first wheel by the wheel-individual electromechanical brake module is defined according to equation (Eq. 1) with: W=∫P dt=∫M1∗ω1dt where P is a friction power of the wheel-individual electromechanical brake module.

[0019] As can be seen from equation (Eq. 1), the friction work W and the friction power P are comparatively high in those operating states of the wheel-specific electromechanical brake module in which the braking torque M1 exerted on the first wheel by the wheel-specific electromechanical brake module and the wheel speed ω1 of the first wheel are high. This is also reflected in the coordinate system of the Fig. 1b, the abscissa of which represents the (normalized) wheel speed ω1 of the first wheel and the ordinate of which represents the (normalized) wheel speed ω1 of the first wheel, the (normalized) braking torque M1 exerted on the first wheel by means of the wheel-individual electromechanical braking module and the (normalized) friction power P defined according to equation (Eq. 1).

[0020] The wheel speed ω1 of the first wheel is related to the wheel slip of the first wheel. If the wheel slip of the first wheel is low, the wheel speed ω1 of the first wheel is correspondingly low. Therefore, if the braking torque M1 exerted on the first wheel by the wheel-specific electromechanical brake module is comparatively high, the wheel speed ω1 of the first wheel is reduced. Accordingly, if the braking torque M1 exerted on the first wheel by the wheel-specific electromechanical brake module is relatively low, the wheel speed ω1 of the first wheel is comparatively high. In both cases described here, the friction power P according to equation (Eq. 1) is relatively low. Therefore, in these operating conditions, no high thermal stress occurs on the wheel-specific electromechanical brake module or any component interacting with it. On the other hand, the values ​​in the coordinate system of the Fig. 1b, operating conditions marked with Φ, which are associated with a high frictional power P, are to be avoided. The operating conditions marked with Φ can also be referred to as thermally critical operating conditions.

[0021] As can be seen from the coordinate system of the Fig. 1a, when carrying out method step S1, an operating state exists in which the wheel speed ω1 of the first wheel is below the predetermined maximum wheel speed value ω 10is reduced and maintained, while during execution of method step S2 the braking torque M1 exerted on the first wheel by means of the wheel-specific electromechanical braking module is reduced and maintained below the specified maximum braking torque value. During both method step S1 and method step S2 the friction power P of the wheel-specific electromechanical braking module is so low that there is no risk of overheating of the wheel-specific electromechanical braking module and / or the components interacting with it. Therefore, a wheel-specific electromechanical braking module can also be (co-)used to carry out the method described here, which is dedicated, smaller in size and more cost-effective (compared to conventional wheel-specific service brakes with high thermal resilience).A design of the wheel-specific electromechanical brake module to withstand high thermal stress is not necessary for the traction control method described here. Thus, the traction control method can also be used to propel or accelerate the vehicle, particularly on μ-split on an incline, to prevent unwanted rolling back of the vehicle and / or unfavorable spinning of the first wheel, using a vehicle component as the wheel-specific electromechanical brake module, which would not be suitable for implementing conventional traction control. A particularly advantageous example of the wheel-specific electromechanical brake module will be discussed below.

[0022] In the embodiment described here, the first wheel is completely locked during the first time interval Δ1 by means of the wheel-specific electromechanical brake module. This causes the wheel speed ω1 of the first wheel to be reduced to (almost) zero and maintained during the first time interval Δ1. Upon execution of method step S2, the wheel lock (applied to the first wheel by means of the wheel-specific electromechanical brake module during the first time interval Δ1) is released during the second time interval Δ2. In this way, the braking torque M1 applied to the first wheel by means of the wheel-specific electromechanical brake module is reduced to (almost) zero and maintained during the second time interval Δ2.However, the complete blocking of the first wheel when executing method step S1 and the removal of the wheel blocking when executing method step S2 is not necessary to execute the traction control method described here.

[0023] As in Fig. 1a, the first time interval Δ1 can be a time duration of the respective method step S1 that is specifically defined for a one-time execution of the method step S1. Therefore, the method steps S1 executed before and after a method step S2 can also have different time durations for the first time interval Δ1. Accordingly, the second time interval Δ2 can also be a time duration of the respective method step S2 that is specifically defined for a one-time execution of the method step S2. The respective time durations for the first time interval Δ1 and / or the second time interval Δ2 can, in particular, correspond to pulse width intervals of a pulse width modulation.

[0024] Fig. 2 shows a flowchart for explaining an embodiment of the method for driving a vehicle axle of a vehicle equipped with two wheels.

[0025] The method described below is (essentially) applicable to all vehicle types / motor vehicle types for which the previously described traction control method can also be implemented. The method described below can be implemented particularly advantageously when the vehicle is traveling on a road with an inhomogeneous road surface and a significant gradient. However, it should be noted that the method's applicability is not limited to this case.

[0026] In an (optional) method step S10 of the method, a starting process of the vehicle is attempted by driving the vehicle axle equipped with the two wheels using at least one motor of the vehicle. Examples of the at least one motor of the vehicle have already been described above.

[0027] If the starting process is successful, the road can be mastered solely by executing method step S10. However, if the starting process is unsuccessful, in particular due to a first friction coefficient of a road surface contacted by a first of the two wheels and / or a difference between the first friction coefficient and a higher second friction coefficient of another road surface contacted by a second of the two wheels, the method is continued using at least one of the method steps described below. Optionally, the vehicle can first be braked using another vehicle axle (equipped with a third wheel and a fourth wheel) as method step S11. In this way, the vehicle can be held even on a significant incline. However, method step S11 is an optional method step.

[0028] If desired, a friction coefficient estimate can be performed in an (optional) method step S12 to determine the first friction coefficient of the road surface contacted by the first wheel. This is possible using a previously measured acceleration of the first wheel during the execution of method step S10. As an alternative to the first friction coefficient, a detectable tire longitudinal force of the first wheel can also be estimated in method step S12. The tire longitudinal force of the first wheel results, for example, from a set of angular momentum of the first wheel by means of a drive torque of the first wheel, a wheel inertia of the first wheel, and an acceleration of the first wheel.

[0029] Based on the first friction coefficient estimated in method step S12, or the deductible longitudinal tire force of the first wheel, a braking torque to be exerted (exclusively) on the first wheel for a successful start of the vehicle during further driving of the vehicle axle can be estimated in an (optional) method step S13. During a further (optional) method step S14, a new start-off process is then carried out while the vehicle axle is further driven by the at least one motor and the first wheel is simultaneously braked using the estimated braking torque. To apply the estimated braking torque (exclusively) to the first wheel, a wheel-specific electromechanical braking module, as already mentioned above, is used. When executing method step S14, the wheel-specific electromechanical braking module is only used to such an extent that the estimated braking torque is approximately achieved.This ensures that only a relatively small amount of slip occurs at the first wheel when method step S14 is executed. Thus, by executing method step S14, the road surface is "climbed" by controlling the wheel-specific electromechanical brake module and the at least one motor. This prevents the first wheel from "catching" the wheel during braking. Accordingly, when method step S14 is executed, heat input from the wheel-specific electromechanical brake module or a component interacting with it is also reduced.

[0030] During the execution of method step S14, an (optional) method step S15 can be performed at least once. Preferably, method step S15 is continuously repeated at a predetermined repetition frequency during the execution of method step S14. In method step S15, a temperature present at the wheel-specific electromechanical brake module or the component interacting with it is measured or estimated. For this purpose, a heat input of the wheel-specific electromechanical brake module or the component interacting with it can be monitored using a predetermined temperature model.If, during the further driving of the vehicle axle by means of the at least one motor while simultaneously braking the first wheel by means of the wheel-specific electromechanical brake module as method step S14, the measured or estimated temperature exceeds a predetermined limit temperature, method step S14 is preferably aborted / terminated. Instead of method step S14, method steps S1 and S2 described above can then be performed alternately. Thus, whenever the temperature measured or estimated in method step S15 reaches a critical level, the traction control method described above can be executed for the first wheel, so that only the operating states that can be executed without (significant) thermal stress are used to "continue to tow" the vehicle along the roadway using the driven second wheel.For this purpose, process steps S1 and S2 are carried out alternately as long as there is an acceleration request from a driver of the vehicle or an automatic system of the vehicle.

[0031] All of the methods described above implement advantageous operating strategies for driving / accelerating a vehicle on an inhomogeneous road surface, such as µ-split, even on a significant road gradient. To implement all of the methods described above, the wheel-specific electromechanical brake module, which can be dedicated, smaller, and more cost-effective than conventional wheel-specific service brakes, can be advantageously used even if its design to withstand thermal stress is omitted. When implementing the methods described above, wear of the wheel-specific electromechanical brake module is reliably prevented, so that it can also be used as a "lifetime brake" if necessary.

[0032] Fig. 3 shows a schematic representation of a vehicle with a vehicle axle equipped with two wheels to explain an embodiment of the control device.

[0033] The Fig. The vehicle / motor vehicle 10 schematically depicted in Figure 3 is merely an example of an electric vehicle equipped with an electric motor 12. However, the usability of the control device 14, explained in more detail below, is not limited to this vehicle type / motor vehicle. Alternatively, the vehicle / motor vehicle 10 can also be a hybrid vehicle or a vehicle / motor vehicle equipped with an internal combustion engine.

[0034] The vehicle axle 18, which is equipped with a first wheel 16a and a second wheel 16b, can be driven by the electric motor 12. For example only, the vehicle 10 is Fig. 3, the vehicle axle 18 driven by the electric motor 12 is a rear axle of the vehicle 10. Likewise, the drivable vehicle axle 18 equipped with the two wheels 16a and 16b can also be a front axle of the vehicle 10. Furthermore, the control device 14 can also be used on a vehicle type / motor vehicle type that has two driven vehicle axles with two wheels each. Fig. The power transmission depicted in Figure 3 from the electric motor 12 to the wheels 16a and 16b via a transmission 20, a differential 22, and drive shafts 24 of the drivable vehicle axle 18 is to be interpreted only as an example. For a better understanding of the advantages of the control device 14 described below, it is also noted here that the differential 22 can be an open differential 22, so that a first drive torque transmitted from the electric motor 12 to the first wheel 16a is always equal to a second drive torque transmitted from the electric motor 12 to the second wheel 16b.

[0035] The control device 14 has an electronic device 14a, which is designed and / or programmed such that, while the vehicle axle 18 is being driven by the electric motor 12 (or at least one other motor of the vehicle 10), traction control for the first wheel 16a can be carried out by means of the electronic device 14a. The driving of the vehicle axle 18 can be a driving of the vehicle axle 18 controlled by the electronic device 14a or detected by the electronic device 14a. The traction control can be carried out for the first wheel 16a by a wheel-specific electromechanical brake module 26a being operable / operated alternately for a predetermined or fixed first time interval in a first mode and for a predetermined or fixed second time interval in a second mode by means of at least one control signal 28 output by the electronic device 14a.The first wheel 16a is braked by the wheel-specific electromechanical brake module 26a operating in the first mode such that a wheel speed / wheel rotational speed of the first wheel 16a is reduced and maintained below a predetermined maximum wheel speed / wheel rotational speed during the first time interval. Furthermore, the braking (applied to the first wheel 16a for the first time interval) is interrupted by the wheel-specific electromechanical brake module 26a operating in the second mode such that a braking torque applied to the first wheel 16a by the wheel-specific electromechanical brake module 26a is reduced and maintained below a predetermined maximum braking torque during the second time interval.

[0036] Thus, the traction control for the first wheel 16a, which can be effected by means of the control device 14 / its electronic device 14a, also achieves the advantages of the methods explained above. It is expressly pointed out here that even when accelerating on a μ-split with a significant gradient, a significant heat input into the wheel-specific electromechanical brake module 26a, or a component interacting with it, is reliably prevented. The component interacting with the wheel-specific electromechanical brake module 26a can be understood, for example, as a multi-disk brake package on which the wheel-specific electromechanical brake module 26a acts.

[0037] As an advantageous development, the control device 14 / electronic device 14a can also be designed and / or programmed to execute further method steps of the method explained above. In particular, the electronic device 14a can be designed and / or programmed to execute the traction control described here for the first wheel 16a whenever at least one measured or estimated temperature present at the wheel-specific electromechanical brake module 26a or at the component interacting with it during the driving of the vehicle axle 18 while simultaneously braking the first wheel 16a by means of a predetermined or fixed braking torque of the wheel-specific electromechanical brake module 26a exceeds a predetermined limit temperature.

[0038] By means of the electronic device 14a, a parking brake module 26a can be operated, in particular as a wheel-specific electromechanical brake module 26a, alternately for the first time interval in the first mode and for the second time interval in the second mode. Thus, a comparatively dedicated, smaller, and cost-effective actuator, whose thermal load capacity is limited, can be used to implement the advantageous traction control for the first wheel 16a. As shown in Fig. As illustrated in Figure 3, in particular, each wheel 16a and 16b of the driven vehicle axle 18 can be assigned its own parking brake module 26a or 26b. Equipping the vehicle 10 with conventional wheel-specific service brakes can thus be dispensed with. In particular, it should be noted that no conventional wheel-specific service brake, which is designed for high thermal load capacity, is required on the driven vehicle axle 18. Instead, the advantageous design / programming of the electronic device 14a achieves a favorable balance between the necessary thermal mass and the cost savings.

[0039] The respective parking brake module 26a can be mounted, in particular, on a differential output of the first wheel 16a. Such centralization of the parking brake module 26a enables a common control unit topology together with the electric motor 12 and contributes to a reduction in cabling effort. Alternatively, the parking brake module 26a can also be arranged adjacent to the first wheel 16a. Likewise, an electromechanical parking brake attached to the wheel 16a can also be used as the wheel-specific electromechanical brake module.

[0040] The control device 14 can, in particular, be a subunit of the wheel-specific electromechanical brake module 26a, such as specifically the parking brake 26a. However, the design of the control device 14 is not limited to any particular control unit type. For example, the control device 14 can also be a central vehicle control unit. Thus, the function of the control device 14 described here can be integrated into a variety of different control unit types.

[0041] The control device 14 can be used particularly advantageously for a vehicle / motor vehicle 10 in which conventional wheel-specific service brakes with high thermal load capacity on the wheels 16a and 16b of the driven vehicle axle 18 are omitted. However, the use of the control device 14 is not limited to this application and can also be used to reduce thermal load in other braking system topologies.

[0042] In order to enable a quick and strong braking of the vehicle 10, this has in the example of Fig. 3 has an eddy current brake 30. The use of the control unit 14 thus enables the use of novel vehicle topologies, such as the use of the eddy current brake 30 for rear-wheel drive electric vehicles. In addition, in the example of the Fig. 3, an electromechanical wheel brake cylinder 32a and 32b is assigned to a wheel 16c and 16d of a further vehicle axle 34. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 214 867 A1

[0002]

Claims

[1] Control device (14) for a vehicle (10) with a vehicle axle (18) equipped with two wheels (16a, 16b) with: an electronic device (14a) which is designed and / or programmed in such a way that, by means of the electronic device (14a), during a drive of the vehicle axle (18) by means of at least one motor (12) of the vehicle (10) which is controlled by the electronic device (14a) or detected by the electronic device (14a), traction control for a first wheel (16a) of the two wheels (16a, 16b) can be carried out by means of the electronic device (14a), in that a wheel-specific electromechanical brake module (26a) can be operated alternately for a predetermined or fixed first time interval (Δ1) in a first mode and for a predetermined or fixed second time interval (Δ2) in a second mode by means of at least one control signal (28) output by the electronic device (14a), wherein the first wheel (16a) is braked by means of the wheel-specific electromechanical brake module (26a) operated in the first mode,that a wheel speed (ω1) of the first wheel (16a) is reduced and maintained below a predetermined maximum wheel speed value during the first time interval (Δ1), and the braking exerted on the first wheel (16a) for the first time interval (Δ1) by means of the wheel-specific electromechanical brake module (26a) operated in the second mode is interrupted such that a braking torque (M1) exerted on the first wheel (16a) by means of the wheel-specific electromechanical brake module (26a) is reduced and maintained below a predetermined maximum braking torque value during the second time interval (Δ2). [2] Control device (14) according to claim 1, wherein the electronic device (14a) is designed and / or programmed to carry out the traction control for the first wheel (16a), provided that it is determined at least as information by means of the electronic device (14a) or provided to the electronic device (14a) that a measured or estimated first variable with respect to a first coefficient of friction of a road surface contacted by the first wheel (16a) is below a predetermined minimum value, a difference between the first variable and a measured or estimated second variable with respect to a higher second coefficient of friction of another road surface contacted by a second wheel (16b) of the two wheels (16a, 16b) is above a predetermined maximum difference and / or a measured or estimated gradient of a road surface traveled by the vehicle (10) is above a predetermined limit gradient. [3] Control device (14) according to claim 1 or 2, wherein the electronic device (14a) is designed and / or programmed to carry out the traction control for the first wheel (16a) if at least one measured or estimated temperature present at the wheel-specific electromechanical brake module (26a) during the driving of the vehicle axle (18) by means of the at least one motor (12) with simultaneous braking of the first wheel (16a) by means of a predetermined or fixed braking torque of the wheel-specific electromechanical brake module (26a) exceeds a predetermined limit temperature. [4] Control device (14) according to one of the preceding claims, wherein by means of the electronic device (14a) as a wheel-individual electromechanical brake module (26a) a parking brake module (26a) can be operated alternately for the first time interval (Δ1) in the first mode and for the second time interval (Δ2) in the second mode. [5] Control device (14) according to one of the preceding claims, wherein by means of the electronic device (14a) as a wheel-individual electromechanical brake module (26a), a parking brake module (26a) mounted on a differential output of the first wheel (16a) can be operated alternately for the first time interval (Δ1) in the first mode and for the second time interval (Δ2) in the second mode. [6] Control device (14) according to one of the preceding claims, wherein the control device (14) is a central vehicle control unit. [7] Parking brake module (26a, 26b) with a control device (14) according to one of claims 1 to 5. [8] Traction control method for a first wheel (16a) of a vehicle axle (18) of a vehicle (10) additionally equipped with a second wheel (16b), wherein, during driving of the vehicle axle (18) by means of at least one motor (12) of the vehicle (10), the following method steps (S1, S2) are carried out alternately: Braking the first wheel (16a) by means of a wheel-specific electromechanical brake module (26a) for a predetermined or fixed first time interval (Δ1) such that a wheel speed (ω1) of the first wheel (16a) is reduced and maintained below a predetermined maximum wheel speed value during the first time interval (Δ1) (S1); and Interrupting the braking exerted on the first wheel (16a) by means of the wheel-specific electromechanical braking module (26a) for the first time interval (Δ1) for a predetermined or fixed second time interval (Δ2) such that a braking torque (M1) exerted on the first wheel (16a) by means of the wheel-specific electromechanical braking module (26a) is reduced and maintained below a predetermined maximum braking torque value during the second time interval (Δ2) (S2). [9] Traction control method according to claim 8, wherein the first wheel (16a) is completely blocked during the first time interval (Δ1) by means of the wheel-specific electromechanical brake module (26a), so that the wheel speed (ω1) of the first wheel (16a) is reduced to zero and maintained during the first time interval (Δ1), and wherein the wheel blocking exerted on the first wheel (16a) by means of the wheel-specific electromechanical brake module (26a) during the first time interval (Δ1) is canceled during the second time interval (Δ2), so that the braking torque (M1) exerted on the first wheel (16a) by means of the wheel-specific electromechanical brake module (26a) is reduced to zero and maintained during the second time interval (Δ2). [10] Method for driving a vehicle axle (18) of a vehicle (10) equipped with two wheels (16a, 16b), comprising the steps: Attempting to start the vehicle by driving the vehicle axle (18) by means of at least one motor (12) of the vehicle (10)(S10); if the starting process is determined to be unsuccessful due to a first coefficient of friction of a road surface contacted by a first wheel (16a) of the two wheels (16a, 16b) and / or a difference between the first coefficient of friction and a higher second coefficient of friction of another road surface contacted by a second wheel (16b) of the two wheels (16a, 16b), further driving of the vehicle axle (18) by means of the at least one motor (12) while simultaneously braking the first wheel (16a) by means of a predetermined or fixed braking torque of a wheel-specific electromechanical braking module (26a)(S14); wherein, if during the further driving of the vehicle axle (18) by means of the at least one motor (12) with simultaneous braking of the first wheel (16a) by means of the predetermined or fixed braking torque of the wheel-specific electromechanical brake module (26a), a measured or estimated temperature present at the wheel-specific electromechanical brake module (26a) exceeds a predetermined limit temperature, a traction control method for the first wheel according to claim 8 or 9 is carried out.

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