motor vehicle, as well as a method for operating an actively steerable wheel suspension

Abstract

The invention relates to a motor vehicle comprising at least the following components: - an actively controlled wheel suspension; - a control device for controlling the actively steerable wheel suspension; - a plurality of individually rotatable drive wheels; and - a drive unit. The motor vehicle is characterized in particular by the fact that, when the vehicle is stationary, at least two of the drive wheels can be individually lifted by means of the actively controllable wheel suspension and can be rotated separately in a lifted state by means of the drive unit. By means of the motor vehicle proposed here and its actively controlled wheel suspension, flat spots can be avoided and thus driving comfort can be increased.

Description

[0001] The invention relates to a motor vehicle and a method for operating an actively controllable wheel suspension.

[0002] When a vehicle is parked for an extended period, its weight rests on the same spot on the tire. This leads to tire deformation, where the part of the tire in contact with the road is flattened. The rubber structure and carcass of the tire are thus stressed and can remain deformed for a considerable time during the next drive. This results in a noticeable imbalance in the steering wheel and reduced vertical comfort. Flat spots develop more quickly, especially on highways with cooler asphalt temperatures, high tire loads, and long periods of inactivity.

[0003] DE 10 2020 111 915 B3 discloses a method for determining vehicle characteristics of a motor vehicle, wherein the motor vehicle has active dampers which can adjust forces on the respective wheel suspensions in order to raise and / or lower the body of the motor vehicle and which can measure the acting forces, wherein specific predetermined adjustment forces of the active dampers are controlled in order to determine a vehicle characteristic from the resulting adjustment and the resulting measured forces.

[0004] DE 10 2017 211 949 A1 discloses a method for steering a four-wheeled motor vehicle, wherein the motor vehicle has a wheel-individual drive with which a drive torque of each wheel of the motor vehicle can be individually adjusted, and adjusting means for changing a wheel load distribution with which a wheel contact force can be individually adjusted, wherein the method comprises the following steps: reducing the wheel contact force of two diagonally opposite wheels of the motor vehicle, turning at least one of the two other wheels and driving at least one of the two other wheels.

[0005] Based on this, the present invention aims to overcome, at least partially, the disadvantages known from the prior art. The features of the invention are defined in the independent claims, with advantageous embodiments described in the dependent claims.

[0006] The invention relates to a motor vehicle comprising at least the following components: - an actively controlled wheel suspension; - a control device for controlling the actively steerable wheel suspension; - a plurality of individually rotatable drive wheels; and - a drive unit.

[0007] The motor vehicle is characterized primarily by the fact that, when the vehicle is stationary, at least two of the drive wheels can be individually lifted by means of the actively controlled wheel suspension and can be rotated separately in a lifted state by means of the drive device.

[0008] Unless explicitly stated otherwise, ordinal numbers used in the preceding and following descriptions serve solely for unambiguous differentiation and do not indicate any order or ranking of the components referred to. An ordinal number greater than one does not necessarily imply the presence of another such component.

[0009] Here is a proposed motor vehicle which has at least an actively controlled wheel suspension, a plurality of drive wheels, and a drive system.

[0010] The actively controlled wheel suspension has at least one actively controlled damper and preferably a spring.

[0011] The damper allows control of the vertical movements of the drive wheel relative to the vehicle body. The damper is connected to the control unit to adjust the damping characteristics in real time. Preferably, the damper is a hydraulic damper with controllable hydraulic pressure. For example, the damper includes a hydraulic pump for controlling the hydraulic pressure within the damper. Thus, the damper is designed so that the drive wheels can be actively raised or lowered relative to the vehicle body by means of the control unit.

[0012] The spring absorbs vertical forces on the drive wheel and provides a restoring force. For example, the spring is also connected to the control unit to adjust its stiffness.

[0013] The control unit is connected to the actively controlled wheel suspension to control the damping of the drive wheels. Preferably, the control unit comprises at least a processor and a data memory.

[0014] Preferably, the motor vehicle has four wheels. Of the four wheels, at least two, preferably all, are designed as drive wheels.

[0015] The drive system comprises, for example, an internal combustion engine and / or one or more electric drive motors. The drive system can provide individual wheel drive torque for each of the drive wheels.

[0016] For example, the total drive torque of the drive system can be achieved using multiple drive motors and / or by means of mechanical or electrical torque distribution. Alternatively or additionally, individual wheel counter-torque can be applied to the vehicle, for example, by means of separately controllable brakes.

[0017] The control unit and the actively controlled wheel suspension are designed to lift and rotate one of the drive wheels at a time when the vehicle is stationary, i.e., when the vehicle is not moving and the drive wheels are therefore not turning.

[0018] Preferably, the control device is designed to lift and rotate the drive wheels one after the other.

[0019] In other words, by means of the actively controlled wheel suspension, preferably each of the drive wheels can be raised at least to the point where the friction of the raised drive wheel against a vehicle surface, such as a road, is reduced sufficiently to allow that raised drive wheel to rotate without moving the vehicle. Preferably, the drive wheels can be completely lifted from the vehicle surface by means of the actively controlled wheel suspension. Preferably, a raised drive wheel can be rotated by means of a wheel-specific drive torque provided by the drive unit. Alternatively or additionally, the vehicle has, for example, individually controllable brakes to provide wheel-specific counter-torques for those drive wheels that are not raised, so that only a single, preferably unbraked, drive wheel is rotated by means of the drive torque.

[0020] The proposed vehicle eliminates flat spots on the tires, thus increasing driving comfort.

[0021] In an advantageous embodiment of the motor vehicle, it is further proposed that the motor vehicle has at least one of the following sensor units in communicating connection with the control unit for determining the condition of the tires: - a temperature sensor; - a pressure sensor; - a time recording device; and - a weight detection device, whereby individual drive wheels can be lifted and rotated by means of the control device based on the determined tire condition.

[0022] The vehicle has a sensor unit that communicates with the control unit. The sensor unit is designed to detect tire characteristics and / or environmental parameters.

[0023] The sensor unit includes, for example, a temperature sensor that measures the tire temperature. Alternatively or additionally, the sensor unit includes a pressure sensor that measures the tire pressure. Preferably, the sensor unit also includes a time recording device that records the vehicle's idle time. For example, the sensor unit includes a weight recording device, which preferably allows the tire load to be measured individually for each wheel.

[0024] For example, the recorded properties and / or environmental parameters constitute a tire condition and / or the tire condition can be determined by means of the control unit based on one or more of the properties and / or environmental parameters.

[0025] The control unit allows the drive wheels to be lifted and rotated based on a determined tire condition.

[0026] In an advantageous embodiment of the motor vehicle, it is further proposed that the motor vehicle has a torque vectoring system for distributing the drive torque to the drive wheels and / or individually controllable brakes for applying an individually controlled counter-torque.

[0027] The vehicle features a torque vectoring system for distributing drive torque to the drive wheels. This system includes, for example, individual wheel hub motors, adjustable transmissions, and / or differentials. Alternatively or additionally, the vehicle has individually controlled brakes to apply counter-torque to the drive wheels.

[0028] According to another aspect, a method for operating an actively steerable wheel suspension of a motor vehicle is proposed, wherein the method is carried out by means of a control device of the motor vehicle when the motor vehicle is stationary and includes at least the following steps in the order mentioned: a. by means of an actively controlled wheel suspension, lifting a single drive wheel of the motor vehicle; b. by means of a drive device, rotating the individual drive wheel raised in step a.; and c. by means of the actively controllable wheel suspension, lowering of the individual drive wheel.

[0029] Here is a proposed method by which the drive wheels of a motor vehicle can be rotated individually in order to avoid flat spots on the tires.

[0030] The procedure is executed by means of a control unit of the motor vehicle, which controls an actively steerable wheel suspension and a drive unit. The procedure comprises at least the following steps a., b., c. in the order listed below.

[0031] In step a., a single drive wheel is simultaneously lifted by means of the steerable wheel suspension. The drive wheel is lifted sufficiently to allow it to be rotated by the drive unit without the vehicle moving. Preferably, the corresponding drive wheel is lifted off the vehicle's surface.

[0032] Step a. is carried out, like the other steps of the procedure, with the vehicle stationary, especially if there is a longer period of inactivity, in order to prevent flat spots on the tires.

[0033] In step b, the drive unit rotates the drive wheel, which was raised in step a. The drive wheel is rotated by a defined adjustment angle. Preferably, the adjustment angle is at least large enough that the previous contact area and the contact area after rotation do not overlap. Preferably, the adjustment angle is not a circular segment resulting from an integer division of a circle. This prevents, for example, the drive wheel from coming to rest on the same contact surface after a complete rotation. For example, the vehicle includes angle sensors to detect the wheel position or the adjustment angle. Alternatively or additionally, the adjustment angle is defined, for example, by a gear ratio and a rotation angle of a drive motor.

[0034] For example, the wheel drive torque required to rotate the drive wheel can be implemented by means of a torque distribution of a total or axle-specific drive torque, by means of wheel-individual wheel drive torques of wheel-individual drive machines, for example wheel hub motors, and / or by means of counter-torques, which are applied to the other drive wheels, for example by means of brakes.

[0035] After rotation, the drive wheel is lowered again in step c. by means of the actively controllable wheel suspension, so that the drive wheel, like the other drive wheels, is fully back on the vehicle surface.

[0036] For example, the next of the drive wheels is then rotated accordingly, preferably until each of the drive wheels has been rotated accordingly.

[0037] In a further advantageous embodiment of the method, it is proposed that in a first step d. a rotation requirement for the drive wheels is determined.

[0038] According to this embodiment, in step d., before step a., a rotation requirement for the drive wheels is determined. The rotation requirement is determined, for example, individually for each wheel, individually for each axle, or as a common value for all drive wheels.

[0039] Step a. and the subsequent steps of the procedure are carried out in such an embodiment depending on the determined rotation requirement. In a particularly simple embodiment, the rotation requirement is a binary value. In such a case, the rotation requirement thus suggests that the procedure should either be carried out or not. For example, if a limit value of a factor, such as a vehicle's idle time, is exceeded, the rotation requirement is set from "do not carry out" to "carry out".

[0040] In a further advantageous embodiment of the method, it is proposed that the need for rotation be determined based on a tire condition, which is preferably determined based on at least one of the following factors: - a period of inactivity of the motor vehicle; - a tire temperature; - tire pressure; and - a tire load.

[0041] According to this embodiment, it is now proposed that the necessity of rotating the tire be determined based on its condition. For example, the necessity of rotating the tire is changed from "do not perform" to "perform" if the tire condition exceeds or falls below a certain threshold.

[0042] The condition of the tires depends, for example, on the vehicle's standing time, tire temperature or ambient temperature, tire pressure and / or tire load, or vehicle weight.

[0043] In an advantageous embodiment of the wheel suspension, it is further proposed that the method for operating a wheel suspension of a motor vehicle is designed according to an embodiment as described above.

[0044] The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, although it should be noted that the drawings are not dimensionally accurate and are not suitable for defining size relationships. It is illustrated in Fig. 1: a schematic representation of a motor vehicle in a side view; Fig. 2: a schematic representation of a motor vehicle in a top view; and Fig. 3: A schematic representation of an actively controlled wheel suspension in a front view.

[0045] In Fig. Figure 1 is a schematic representation of a motor vehicle 1 in a side view. The motor vehicle 1 has a body 16 and four drive wheels, of which two drive wheels 4 and 6 are shown. Under normal operating conditions, the drive wheels 4 and 6 are in contact with a vehicle base 11. As shown, a first front drive wheel 4 is raised. The raised first drive wheel 4 is completely lifted from the vehicle base 11, so that it can be rotated by means of a drive mechanism 8 of the motor vehicle 1. A second, rear drive wheel 6, as well as the hidden drive wheels 5 and 7 (see Figure 1), are also shown. Fig. 2) remain in contact with the vehicle's underbody 11. The lifting and rotation of the first drive wheel 4 is carried out by means of an actively controllable wheel suspension 2 and the drive unit 8.

[0046] The drive wheel 4 is equipped with an actively controllable wheel suspension 2 (compare Fig. 3) raised. In this process, a wheel-specific drive torque is applied to the first drive wheel 4. The wheel-specific drive torque is therefore greater than the drive torques of the other drive wheels 5, 6, 7, or only the first drive wheel 4 receives a drive torque. For this purpose, a drive torque from a drive motor 22, 23 is distributed wheel-specifically by means of a torque vectoring system 10 (compare Fig. 2).

[0047] Preferably, the first drive wheel 4 is lifted and rotated by a defined adjustment angle 12 using the following method. The adjustment angle 12 is such that the contact surfaces of the drive wheel 4 preferably do not overlap before and after the rotation, and that after a complete rotation of the drive wheel 4, for example after the process has been carried out several times at intervals, the drive wheel 4 does not come to rest in the same position again.

[0048] In a first step d., a rotation requirement for the first drive wheel 4 is determined. The rotation requirement is determined, for example, individually for each wheel, individually for each axle, or as a common value for all drive wheels 4, 5, 6, 7.

[0049] In the subsequent step a., only one of the drive wheels 4, 5, 6, 7 is raised simultaneously using the actively controllable wheel suspension 2. Here, the first drive wheel 4 is raised as an example, as explained above.

[0050] In step b., the first drive wheel 4, which was raised in step a., is rotated by means of the drive device 8, as explained above. Here, the first drive wheel 4 is rotated by a defined adjustment angle 12.

[0051] After rotation, the first drive wheel 4 is lowered again in step c. by means of the actively controllable wheel suspension 2, so that the first drive wheel 4, like the other drive wheels 5, 6, 7, is once again fully in contact with the vehicle surface 11. For example, a next drive wheel, such as the third drive wheel 6, is then rotated accordingly.

[0052] In Fig. Figure 2 is a schematic representation of a motor vehicle 1 shown in a top view. The motor vehicle 1 is, for example, a motor vehicle 1 as described in relation to Fig. Section 1 explains why reference is made to the corresponding description and why only differences and additional recognizable features are explained here.

[0053] The motor vehicle 1 comprises a drive unit 8 with axle-specific electric drive motors 22, 23. An electric drive motor 22, 23 is provided on each axle, which is connected to the respective drive wheels 4, 5, 6, 7 by means of a torque vectoring system 10. Thus, the drive torque of the front electric drive motor 22 can be distributed to the front drive wheels 4, 5 by means of the torque vectoring system 10, and the drive torque of the rear electric drive motor 23 can be distributed to the rear drive wheels 6, 7 by means of the additional torque vectoring system 10, shown at the rear. The torque vectoring systems 10 and the electric drive motors 22, 23 can be controlled by means of a control unit 3, as can the actively controllable wheel suspension 2 (see figure). Fig. 3).

[0054] In Fig. Figure 3 is a schematic representation of an actively controllable wheel suspension 2 according to Fig. 1 or Fig. Figure 3 shows a schematic view. The actively steerable wheel suspension 2 is connected to the control unit 3. Each of the four drive wheels 4, 5, 6, 7, and, in this illustration, the fourth drive wheel 7, is mounted on the body 16 of the motor vehicle 1 by means of such a wheel suspension 2. The actively steerable wheel suspension 2 includes a wheel bearing 17, by means of which the drive wheel 7 is pivotably mounted on the body 16.

[0055] The wheel suspension 2 further comprises a sensor unit 9, a hydraulic pump 13, a spring 14, and a damper 15. The damper 15 is a hydraulic damper 15, which is supplied with hydraulic pressure by the hydraulic pump 13. The hydraulic pump 13, or rather its pump motor 21, is connected to the control unit 3 to adjust the damping characteristics in real time. The hydraulic pump 13 is driven by the pump motor 21, which is controlled based on a pressure value determined by the pressure gauge 20. The wheel suspension 2 also includes two throttles 18 and two check valves 19, which are arranged in the hydraulic circuit of the damper 15.

[0056] By means of the motor vehicle proposed here and its actively controlled wheel suspension, flat spots can be avoided and thus driving comfort can be increased.

Claims

[1] Motor vehicle (1) comprising at least the following components: - an actively controlled wheel suspension (2); - a control device (3) for controlling the actively steerable wheel suspension (2); - a plurality of individually rotatable drive wheels (4, 5, 6, 7); and - a drive unit (8), wherein, in a vehicle standstill, at least two of the drive wheels (4, 5, 6, 7) can be individually lifted by means of the actively controllable wheel suspension (2) and can be separately rotated in a lifted state by means of the drive device (8), characterized by , that the motor vehicle (1) has at least one of the following sensor units (9) in communicating connection with the control unit (3) for determining a tire condition: - a temperature sensor; - a pressure sensor; - a time recording device; and - a weight recording device, wherein by means of the control device (3) individual drive wheels (4,5,6,7) can be lifted and rotated on the basis of the determined tire condition. [2] Motor vehicle (1) according to claim 1, wherein the motor vehicle (1) has a torque vectoring system (10) for distributing the drive torque to the drive wheels (4,5,6,7) and / or individually controllable brakes for applying an individually controlled counter-torque. [3] Method for operating an actively steerable wheel suspension of a motor vehicle (1) to avoid flat spots on the tires, wherein the method is carried out by means of a control device (3) of the motor vehicle (1) when the motor vehicle (1) is stationary and comprises at least the following steps in the order mentioned: a. by means of an actively controllable wheel suspension (2), lifting a single drive wheel (4) of the motor vehicle (1); b. by means of a drive device (8), rotating the individual drive wheel (4) raised in step a. by a defined adjustment angle (12); and c. by means of the actively controllable wheel suspension (2), lowering of the individual drive wheel (4). [4] Method according to claim 3, wherein in a first step d. a rotation requirement for the drive wheels (4,5,6,7) is determined. [5] Method according to claim 3 or claim 4, wherein the need for rotation is determined based on the condition of the tire. [6] Method according to claim 5, wherein the tire condition is determined on the basis of at least one of the following factors: - a period of inactivity of the motor vehicle (1); - a tire temperature; - tire pressure; and - a tire load.

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