Multi-axle vehicle with manoeuvring aid

Abstract

The present disclosure relates to a vehicle, in particular a heavy goods vehicle, with a manoeuvring aid or with improved manoeuvring properties and with a reduced turning circle, in order to save costs for the power steering, in particular by way of an optimised dimensioning, comprising: at least one steerable front axle and at least two rear axles, a control device, which is designed to adjust an axle load which acts on at least one of the at least two rear axles and / or on at least one second steerable front axle which is arranged behind the first steerable front axle, the control device being designed to reduce the axle load on at least one of the at least two rear axles and to shift it to at least one other rear axle arranged further to the front and / or onto the second steerable front axle or to shift it onto a rear axle arranged further to the rear if the at least one of the at least two rear axles on which the axle load is reduced is a steerable rear axle.

Description

[0001] Multi-axle vehicle with shunting aid

[0002]

[0001] The present disclosure relates to a multi-axle vehicle with a maneuvering aid, in particular a multi-axle vehicle with at least three axles for reducing the turning circle and / or for reducing the required steering torque. The multi-axle vehicle preferably has at least one steerable front axle and at least two rear axles. The multi-axle vehicle is preferably a truck. The present invention relates in particular to a maneuvering aid for either reducing the turning circle of the vehicle by shifting the vehicle's center of gravity forward and / or for reducing the required steering forces by reducing an axle load of at least one steerable rear axle.

[0003] background

[0004]

[0002] Vehicles, particularly trucks, often have a large turning circle. In order to improve maneuverability, it is necessary to reduce the turning circle of the vehicle. In addition, with heavy loads, large steering forces are required to steer such vehicles and to ensure lower steering forces or steering moments on the steering wheel for the driver. To reduce the steering forces, all rear axles can be non-steerable and thus rigid. Therefore, only steering moments need to be applied to deflect the front wheels. However, vehicles with rigid rear axles have a large turning circle.

[0003] To achieve a smaller turning circle, at least one rear axle can be steerable. Particularly with high axle loads, the forces orThe torques required to steer the steerable rear axles may be so high that steering is no longer possible without sufficient steering assistance, especially when the vehicle is stationary or traveling at low speeds. Especially when using small-sized and / or inexpensive steering assistance systems, especially hydraulic, electric, or electro-hydraulic steering assistance systems, the steering assistance may be too small to enable steering of the steerable rear axles, especially when stationary or traveling at low speeds.

[0005]

[0004] For this reason, oversized power steering systems are often used in the current state of the art. In some cases, the steerable rear axles are centered and / or locked to at least allow the front axle to steer, so that the vehicle remains maneuverable, or it is accepted that the vehicle cannot be steered when stationary.

[0006] Disclosure of the invention

[0007]

[0005] It is an object of the present disclosure to provide a vehicle with maneuvering assistance or with improved maneuvering characteristics and thus with a reduced turning circle, while saving costs for the steering assistance, in particular through optimized dimensioning. In this case, either steerable rear axles should be dispensed with entirely, or small or undersized steering assistance systems, which preferably support the steering force at the rear axle electrically, electro-hydraulically, or hydraulically, should be able to be used. "Too small," in the sense of these statements, means that the steering assistance is insufficient to enable steering without the use of the solution proposed by the invention.

[0008]

[0006] Preferably, the steering forces for deflecting the steerable rear axles, for example, a steerable leading axle and / or trailing axle, should be low, without the use of oversized steering assistance or any steering assistance at all, and thus the steering angle on the axle can be adjusted more easily and quickly, preferably when stationary and / or at low speeds. This should reduce the frictional force between the tires and the road. This reduces tire and road wear.

[0009]

[0007] This object is achieved by the subject matter of the independent claims. Advantageous embodiments are specified in the subclaims.

[0010]

[0008] According to an independent aspect of the present invention, a vehicle is specified, in particular a truck, comprising: at least one steerable front axle and at least two rear axles, wherein preferably at least one rear axle is driven, a control device which is configured to adjust an axle load acting on at least one of the at least two rear axles and / or on at least one second steerable front axle which is located behind the first steerable front axle, wherein the control device is configured to reduce the axle load on at least one of the at least two rear axles and to shift it to at least one other rear axle which is located further forward and / or to the second steerable front axle or to shift it to a rear axle which is located further back if the at least one of the at least two rear axles on which the axle load is reduced is a steerable rear axle.

[0011]

[0009] By shifting the axle load to an axle located further away, for example the second steerable front axle or the further rear axle, it can be achieved that the instantaneous center of gravity of the vehicle is shifted further forward and / or that a coefficient of friction between the wheels and the road surface is reduced with rear axles located further back compared to rear axles located further forward.

[0012]

[0010] During a planar movement of the vehicle, i.e., when viewed from above, the instantaneous center of gravity is the point in space around which the vehicle can be considered and treated as rotating only at least for an infinitesimal point in time. By shifting the instantaneous center of gravity forward or by reducing the radius between the instantaneous center of gravity and the vehicle, the turning circle of the vehicle is reduced.

[0013]

[0011] By shifting the axle load to a more forward axle and / or a more rearward axle, the axle load on a steerable rear axle can be reduced. This allows the coefficient of friction between the wheels of the steerable rear axle and the road surface to be reduced. This ensures that the steerable axle can be steered with less force or steering torque.

[0012] According to another aspect of the present invention, a vehicle is provided, in particular a truck, comprising: at least one steerable front axle and at least two rear axles, wherein preferably at least one rear axle is driven, a control device configured to adjust an axle load acting on at least one of the at least two rear axles and / or on at least one second steerable front axle located behind the first steerable front axle, a steering force detection device for detecting a steering force on one of the axles,on which the axle load is adjustable, wherein the control device is configured to reduce the axle load on at least one of the at least two rear axles and to shift it to at least one other rear axle and / or to the second steerable front axle when the steering force detection device detects a steering force that is higher than a predetermined value and / or detects a steering angle that is smaller than another predetermined value.

[0014]

[0013] The steering force detection device may comprise a force sensor and / or a torque sensor for determining the steering force or the steering torque at the steering wheel and / or the handlebar and / or at the at least one steerable front axle and / or the at least one steerable rear axle. Furthermore, the steering force detection device may alternatively or additionally comprise an angle sensor for determining the steering angle of the at least one steerable front axle and / or the at least one steerable rear axle.

[0015]

[0014] For example, the steering force detection device can detect a steering torque via the torque sensor and / or the steering angle realized thereby. The control device can adjust the axle load or the axle load distribution on at least one of the rear axles and / or front axles based on the comparison of the steering torque with a specific value and the steering angle with another specific value.

[0016]

[0015] The steering force detection device further has the advantage that the steering force required to turn the wheels can be measured. This allows the steering force required to turn the wheels to be adjusted more precisely. For example, the steering torque applied by a driver or an automated system is already very high, and the steering angle is still almost zero. In this case, for example, by relieving the load on at least one of the steerable axles, the steering angle can be increased with the same or a similar steering torque, thus reducing the steering force and / or the turning circle.

[0017]

[0016] Preferably, the control device of the vehicle is configured to reduce the axle load on at least one of the at least two rear axles when there is a user input to reduce a turning circle.

[0018]

[0017] By reducing the axle load on at least one rear axle, a reduced turning circle can be achieved. Because the user can change the axle load via an input, it is possible for the user to reduce the turning circle if necessary, for example, when maneuvering the vehicle.

[0019]

[0018] For example, the steering torque applied by a driver or an automated system is already very high, and the steering angle is still too small to achieve the desired turning circle. In this case, the steering angle can be reduced with the same or lower steering force or the turning circle, for example, by changing the axle load.

[0020]

[0019] Furthermore, the user can also increase the stability of the vehicle by increasing the axle load on the rear axle. This can be advantageous, for example, when driving straight ahead.

[0021]

[0020] Preferably, the at least one rear axle of the vehicle to which the axle load is shifted is the drive axle and / or a rigid leading axle.

[0022]

[0021] If the rear axle of the vehicle, to which the axle load is shifted, is the drive axle, this is advantageous because a friction force between the tire and the road is large enough so that the power from the drive axle can be transmitted at least largely without slippage.

[0023]

[0022] The leading axle is not the last axle of the vehicle, meaning a leading axle is located in front of another rear axle; a rigid leading axle is not steerable. If the rear axle of the vehicle, to which the axle load is shifted, is a rigid leading axle, the turning circle is reduced and the vehicle's weight is shifted to a non-steerable axle. This reduces the axle load on, for example, a steerable rear axle, which can then be steered more smoothly and with less force or steering torque.

[0024]

[0023] Preferably, at least one of the rear axles of the vehicle on which the axle load is reduced is a trailing axle and / or a steerable leading axle.

[0025]

[0024] The trailing axle has at least one of the leading axles and / or at least one of the drive axles in front of it. Additional rear axles can be arranged behind the trailing axle. However, no additional rear axle can be arranged behind the trailing axle. If the rear axle of the vehicle, on which the axle load is reduced, is a trailing axle, the vehicle's turning circle is reduced. If the rear axle of the vehicle, on which the axle load is reduced, is a steerable leading axle, it is smoother to move, i.e., it can be steered with less force or steering torque.

[0026]

[0025] Preferably, the at least one rear axle on which the axle load is reduced can be relieved by a predetermined axle load value, and / or the at least one rear axle on which the axle load is reduced is relieved until the vehicle falls below a defined, predetermined turning circle when maneuvering. The predetermined axle load value and / or the predetermined turning circle can be selected depending on the user input, or the predetermined axle load value and / or the predetermined turning circle can be stored in the control device.

[0027]

[0026] Preferably, the at least one rear axle on which the axle load is reduced is steerable in order to be able to steer it more smoothly and with less force or steering torque.

[0028]

[0027] Preferably, the at least one steerable rear axle on which the axle load is reduced is relieved until it can be steered with a predetermined steering force.

[0029]

[0028] Preferably, the steering of the at least one steerable rear axle is blocked or locked as soon as it cannot be steered with the predetermined steering force. This means that the steerable axle cannot be further steered in or out because the steering force is too high for the under-designed steering system. To prevent damage to the steering system, in such a case, the steering movement of the steerable axle is actively prevented, blocked, locked, or centered.

[0030]

[0029] The predetermined steering force can be selected depending on a maximum steering force for the user. The maximum steering force can be further selected depending on the user's input.

[0031]

[0030] Preferably, the predetermined steering force and / or the predetermined turning circle is adjustable; and / or the predetermined steering force and / or the predetermined turning circle can be displayed via a display device.

[0032]

[0031] Preferably, the vehicle has a steering force assistance device that acts on at least one steerable rear axle, on which the axle load is reduced, to assist the steering force. This reduces the steering force required by the user, or the user no longer needs to apply any steering force. The predetermined steering force can be selected depending on the maximum steering force assistance of the steering force assistance device.

[0033]

[0032] Preferably, the at least one steerable rear axle on which the axle load is reduced is relieved depending on the available steering force assistance or by a defined value.

[0034]

[0033] Preferably, the steering power assistance is provided electrically, electro-hydraulicly and / or hydraulically.

[0035]

[0034] Preferably, an axle load reduction or an axle load change can only be activated up to a predeterminable speed, e.g., up to 5 km / h or 10 km / h. Axle load reduction means that the axle load acting on at least one of the at least two rear axles and / or on at least the second steerable front axle located behind the first steerable front axle is reduced, if appropriate, according to one of the previously mentioned preferred embodiments. Axle load change means that the axle load acting on at least one of the at least two rear axles and / or on at least the second steerable front axle located behind the first steerable front axle is shifted to another axle, if appropriate, according to one of the previously mentioned preferred embodiments. An axle load change, sometimes also referred to as axle load shift, means that the axle base or wheelbase is not changed.The axle load change is intended to change the instantaneous center of gravity.

[0036]

[0035] For example, the vehicle has three rear axles with a leading axle, a trailing axle and a drive axle located between the trailing axle and the leading axle.

[0037]

[0036] For example, the vehicle has two rear axles with a trailing axle and a driving axle.

[0038]

[0037] For example, the vehicle has two rear axles with a leading axle and a driving axle.

[0039]

[0038] Preferably, the vehicle has a steerable front axle and / or two steerable front axles.

[0039] Preferably, at least one of the at least two rear axles is connected to a chassis of the vehicle by a spring device, wherein the load on at least one of the at least two rear axles can be relieved by reducing the spring stiffness.

[0040]

[0040] Preferably, at least one of the two rear axles has an air suspension, wherein by venting the air suspension on one of the rear axles, the load can be reduced compared to that of at least one other rear axle and / or compared to at least one steerable front axle and / or another of the rear axles can be subjected to a greater load by increasing the pressure in the air suspension compared to the relieved rear axle and / or compared to at least one steerable front axle.

[0041] Short description of the drawings

[0042] The invention is explained in more detail below with reference to figures, in which:

[0043] Fig. 1 shows an exemplary axle load distribution of a loaded vehicle with a steerable drive axle and two rear axles,

[0044] Figure 2 shows an exemplary axle load distribution with activated maneuvering aid of a loaded vehicle with one steerable drive axle and two rear axles,

[0045] Figure 3 shows a change in axle load with active manoeuvring aid with one steerable front axle and two rear axles as a double axle transmission,

[0046] Figure 4 shows an instantaneous pole shift with active shunting aid with one steerable front axle and two rear axles as a double-axle transmission,

[0047] Figure 5 shows a change in axle load with active manoeuvring aid with a steerable front axle and rigid trailing axle,

[0048] Figure 6 shows an instantaneous center of gravity shift of the axle load with active shunting aid with a steerable front axle and rigid trailing axle,

[0049] Figure 7 shows a change in axle load with active manoeuvring aid with a steerable front axle and rigid leading axle,

[0050] Figure 8 shows an instantaneous center of gravity shift of the axle load with active shunting aid with a steerable front axle and rigid leading axle,

[0051] Figure 9 shows a change in axle load with active maneuvering aid and second steerable drive axle,

[0052] Figure 10 shows an instantaneous pole shift with active shunting aid and second steerable drive axle,

[0053] Figure 11 shows a change in axle load with active shunting aid and steerable leading axle,

[0054] Figure 12 shows a change in axle load with active shunting aid and steerable trailing axle.

[0055] Embodiments of the Disclosure

[0041] Figure 1 shows an exemplary axle load distribution of a vehicle, for example, a truck or a bus. In the exemplary embodiment shown, the vehicle comprises a chassis 5. A driver's cab 3 and a box body 4 are mounted on the chassis 5. Furthermore, other known embodiments of a vehicle with at least three axles are also conceivable. For example, the driver's cab 3 and the box body 4 do not have to be separate, or the box body 4 can also be a dump truck or a flatbed.

[0056]

[0042] The vehicle has a steerable drive axle 1 and two rear axles 2, which are connected to the chassis 5. The front drive axle can be a drive axle 21 and the rear drive axle 2 can be a trailing axle 22, i.e., the trailing axle 22 is arranged behind the drive axle 21. For example, the drive axle 21 is subjected to an axle load of 13 t, and the trailing axle 22 is subjected to an axle load of 9 t.

[0057]

[0043] Figure 2 shows axle load distribution with activated maneuvering assistance of a loaded vehicle, as shown in Figure 1. For example, a 2-ton axle load is shifted from the trailing axle 22 to the drive axle 21. Due to the example of modified axle load distribution with active maneuvering assistance, a 15-ton axle load acts on the drive axle 21, and a 7-ton axle load acts on the trailing axle 22. By shifting the axle load from the trailing axle 22 to the drive axle 21, the vehicle's instantaneous center of gravity is shifted forward. This results in a smaller turning circle for the vehicle.

[0058]

[0044] Figure 3 shows a further embodiment of the vehicle shown in Figure 1. In contrast to the vehicle in Figure 1, the vehicle in Figure 3 has two rear axles 2 with activated maneuvering assistance. Thus, the vehicle in Figure 3 has two rear axles 2 configured as drive axles 22. The axle load change caused by the activated maneuvering assistance is illustrated by the arrows, ie, the axle load on the rear drive axle 21 is reduced and the axle load on the front drive axle 21 is increased.

[0059]

[0045] Figure 4 shows an instantaneous pole shift 33 of the vehicle shown in Figure 3, which can be achieved by changing the axle load, which is schematically indicated by the arrows in Figure 3. The instantaneous pole is, during a planar movement of the vehicle, i.e., when viewed from above, the point in space around which the vehicle can be regarded and treated as only rotating, at least at an infinitesimal point in time. Without the axle load change, the vehicle reaches the initial turning circle 31, i.e., the vehicle turns around a further-toward instantaneous pole or center point of the initial turning circle 31. The axle load change causes an instantaneous pole shift 33; for example, the instantaneous pole of the vehicle is shifted further forward, and / or a change in the coefficient of friction between the edges and the road surface is achieved.As a result, the vehicle turns around a less distant center point (smaller radius) of the reduced turning circle 32 shown in dashed lines.

[0060]

[0046] Figure 5 shows a further embodiment of the vehicle shown in Figure 3. In contrast to the vehicle in Figure 3, the vehicle in Figure 5 has only one rear axle 2, which is designed as a drive axle 21. The second rear axle 2 is a trailing axle 22, i.e., formed behind the drive axle 21.

[0047] Figure 6 shows an instantaneous pole shift 33 of the vehicle shown in Figure 5, which can be achieved by changing the axle load, which is schematically indicated in Figure 5 by the arrows. Without changing the axle load, the vehicle achieves the initial turning circle 31, i.e., the vehicle turns around a more distant center point of the initial turning circle 31. The axle load change causes the instantaneous pole shift 33, for example, the instantaneous pole of the vehicle is shifted further forward, and / or a change in the coefficient of friction between the edges and the roadway is achieved.As a result, the vehicle turns around the less distant center of the reduced turning circle 32 shown in dashed lines.

[0061]

[0048] Figure 7 shows a further embodiment of the vehicle according to Figure 3. In contrast to the vehicle in Figure 3, the vehicle in Figure 7 has only one driven rear axle 21. The second rear axle 2 is a leading axle 23, ie, it is formed in front of the drive axle 21.

[0062]

[0049] Figure 8 shows an instantaneous center of gravity shift 33 of the vehicle illustrated in Figure 7, which can be achieved by changing the axle load, which is schematically indicated by the arrows in Figure 7. Without changing the axle load, the vehicle achieves the initial turning circle 31, i.e., the vehicle turns around a more distant center point of the initial turning circle 31. The axle load change causes the instantaneous center of gravity shift 33; for example, the instantaneous center of gravity of the vehicle is shifted further forward, and / or a change in the coefficient of friction between the edges and the road surface is caused. As a result, the vehicle turns around the more distant center point of the reduced turning circle 32, shown in dashed lines.

[0063]

[0050] Figure 9 shows a further embodiment of the vehicle shown in Figure 3. In contrast to the vehicle shown in Figure 3, the vehicle shown in Figure 9 has a second steerable front axle 12 arranged behind the first steerable rear axle 11. Furthermore, in the embodiment of the vehicle shown in Figure 9, as indicated by the arrows, the rear axle 2 located further forward, which is designed as a drive axle 21, is unloaded and the second steerable rear axle 22 is loaded.

[0064]

[0051] Figure 10 shows an instantaneous center of gravity shift 33 of the vehicle illustrated in Figure 9, which can be achieved by changing the axle load, which is schematically indicated by the arrows in Figure 9. Without changing the axle load, the vehicle achieves the initial turning circle 31, i.e., the vehicle turns around a more distant center point of the initial turning circle 31. The axle load change causes the instantaneous center of gravity shift 33, for example, the vehicle's instantaneous center point is shifted further forward, and / or a change in the coefficient of friction between the edges and the road surface. As a result, the vehicle turns around the more distant center point of the reduced turning circle 32, shown in dashed lines.

[0065]

[0052] Figure 11 shows a further embodiment of the vehicle shown in Figure 3. In contrast to the vehicle shown in Figure 3, the vehicle shown in Figure 11 has a steerable rear axle 2 which is designed as a steerable leading axle 23, i.e. the steerable rear axle 2 is formed in front of the drive axle 21. As schematically indicated by the arrows, the change in the axle load distribution when the maneuvering aid is activated relieves the load on the steerable leading axle 23 and loads the drive axle 21, which is not designed to be steerable, for example. By reducing the load on the steerable leading axle 23, a frictional force between the wheels and the road can be reduced when the wheels of the steerable leading axle 23 are turned. Therefore, the steerable leading axle 23 can be steered or turned more easily and therefore with less force or steering torque due to the relief.

[0066]

[0053] Figure 12 shows a further embodiment of the vehicle shown in Figure 3. In contrast to the vehicle shown in Figure 3, the vehicle shown in Figure 12 has a steerable rear axle 2 which is designed as a steerable trailing axle 22, i.e. the steerable rear axle 2 is formed behind the drive axle 21. As schematically indicated by the arrows, the change in the axle load distribution when the maneuvering aid is activated relieves the load on the steerable trailing axle 22 and loads the drive axle 21, which is not designed to be steerable, for example. By reducing the load on the steerable trailing axle 22, a frictional force between the wheels and the road can be reduced when the wheels of the steerable trailing axle 22 are turned. Therefore, the steerable trailing axle 22 can be steered or turned more easily and therefore with less force or steering torque due to the relief.

[0067]

[0054] The axle load variation can be achieved, for example, by increasing and decreasing the pressure of at least one air suspension and / or hydraulic suspension and / or hydropneumatic suspension between one of the front axles 1 and the driver's cab 3 and / or one of the rear axles 2 and the body 4. If the pressure in at least one of the air suspensions (air bellows) and / or hydraulic suspensions and / or hydropneumatic suspensions is increased, the axle is subjected to a greater load. If the pressure in at least one of the air suspensions and / or hydraulic suspensions and / or hydropneumatic suspensions is reduced, the axle is subjected to a lesser load.

[0068] List of reference symbols

[0069] 1 front axle

[0070] 2 rear axles

[0071] 3 Driver's cab

[0072] 4 suitcases

[0073] 5 Chassis

[0074] 11 first steerable front axle

[0075] 12 second steerable front axle

[0076] 21 Drive axle

[0077] 22 Trailing axle

[0078] 23 Leading axle

[0079] 31 Exit turning circle

[0080] 32 reduced turning circle

[0081] 33 Instantaneous pole shift

Claims

Claims 1. Vehicle, in particular a truck, comprising: at least one steerable front axle (1) and at least two rear axles (2), a control device configured to adjust an axle load acting on at least one of the at least two rear axles (2) and / or on at least one second steerable front axle (1) located behind the first steerable front axle, wherein the control device is configured to reduce the axle load on at least one of the at least two rear axles (2) and to transfer it to at least one other rear axle (2) located further away and / or to the second steerable front axle (12) or to a rear axle located further back, if the at least one of the at least two rear axles (2) on which the axle load is reduced is a steerable rear axle.

2. Vehicle according to claim 1 with a steering force detection device for detecting a steering force on one of the axles, wherein the control device is configured to adjust the axle load when the steering force detection device detects a steering force that is higher than a predetermined value and / or detects a steering angle that is smaller than a further predetermined value.

3. Vehicle, in particular a truck, comprising: at least one steerable front axle (1) and at least two rear axles (2), a control device configured to adjust an axle load acting on at least one of the at least two rear axles (2) and / or on at least one second steerable front axle (1) located behind the first steerable front axle, a steering force sensing device for detecting a steering force on one of the axles on which the axle load is adjustable, wherein the control device is configured to reduce the axle load on at least one of the at least two rear axles (2) and transfer it to at least one other rear axle (2) and / or to the second steerable front axle (12) when the steering force sensing device detects a steering force that is higher than a predetermined value and / or detects a steering angle that is less than a further predetermined value.

4. Vehicle according to one of the preceding claims, wherein the control device is configured to reduce the axle load on at least one of the at least two rear axles (2) when a user input to reduce a turning circle is received.

5. Vehicle according to one of the preceding claims, wherein the at least one rear axle (2) onto which the axle load is transferred is the drive axle (21) or a rigid leading axle (23).

6. Vehicle according to one of the preceding claims, wherein at least one of the rear axles (2) at which the axle load is reduced is a trailing axle (22) and / or a steerable leading axle (23).

7. Vehicle according to one of the preceding claims, wherein the at least one rear axle (2) at which the axle load is reduced can be relieved by a predetermined axle load value; and / or wherein the at least one rear axle (2) at which the axle load is reduced is relieved to such an extent that the vehicle falls below a defined predetermined turning circle when maneuvering.

8. Vehicle according to one of the preceding claims, wherein the at least one rear axle (2), at which the axle load is reduced, is steerable.

9. Vehicle according to claim 8, wherein the at least one steerable rear axle (2), at which the axle load is reduced, can be relieved of load until it can be steered with a predetermined steering force; and / or wherein the steering of the at least one steerable rear axle (2) can be locked as soon as it can no longer be steered with the predetermined steering force.

10. Vehicle according to one of the preceding claims, wherein the predetermined steering force and / or the predetermined turning circle is adjustable; and / or wherein the predetermined steering force and / or the predetermined turning circle can be displayed and / or adjusted via a display device.

11. Vehicle according to one of claims 2 to 9, with a power steering assist device which acts on at least one steerable rear axle (2) where the axle load is reduced in order to assist the steering force.

12. Vehicle according to one of claims 10, wherein the at least one steerable rear axle (2), at which the axle load is reduced, is relieved depending on the available power steering assistance or by a defined value.

13. Vehicle according to claim 10 or 11, wherein the power steering assistance is electric, electro-hydraulic and / or hydraulic.

14. Vehicle according to one of the preceding claims, wherein an axle load reduction or an axle load change can only be activated up to a predefinable speed.

15. Vehicle according to one of the preceding claims, wherein the vehicle has three rear axles (21, 22, 23) with a leading axle (23), a trailing axle (22) and a drive axle (21) located between the trailing axle (22) and the leading axle (23); or wherein the vehicle has two rear axles (21, 23) with a trailing axle (23) and a drive axle (21), or wherein the vehicle has two rear axles (21, 23) with a leading axle (22) and a drive axle (21), and / or wherein the vehicle has a steerable front axle (11); and / or wherein the vehicle has two steerable front axles (11, 12).

16. Vehicle according to one of the preceding claims, wherein at least one of the at least two rear axles (2) is connected to a chassis (5) of the vehicle by a spring device, wherein the at least one of the at least two rear axles (2) can be relieved of load by reducing a spring stiffness.

17. Vehicle according to claim 16, wherein at least one of the two rear axles (2) has an air suspension, wherein by venting the air suspension one of the rear axles (2) can be relieved of load compared to the at least one other rear axle (2) and / or compared to at least one steerable front axle (1) and / or by increasing the pressure in the air suspension one of the rear axles can be subjected to a higher load compared to the at least one other rear axle and / or compared to at least one steerable front axle.

Images