WO2022213136A1

WO2022213136A1 - Electrified steering and drive system with skid steering

Info

Publication number: WO2022213136A1
Application number: PCT/AT2022/060104
Authority: WO
Inventors: Martin Huber; Gerhard Skoff
Original assignee: Avl List Gmbh; Avl Commercial Driveline & Tractor Engineering Gmbh
Priority date: 2021-04-07
Filing date: 2022-04-06
Publication date: 2022-10-13
Also published as: AT524771A4; AT524771B1

Abstract

The invention relates to a crawler vehicle having: a first vehicle unit (1) with two tracks (16, 17) and a first drive system (6, 8, 9, 10); a second vehicle unit (2) with two tracks (18, 19); and a coupling element which mechanically connects the two vehicle units (1, 2) and has two joints (4, 5) and a coupling rod (3). The coupling rod (3) connects the two joints (4, 5) at a defined distance to each other, the first joint (4) and the second joint (5) have at least one respective vertical rotational axis, and the tracks of the first vehicle unit (1) and the second vehicle unit (2) have crawlers, in particular crawler chains or rubber chains, wherein in the vehicle longitudinal direction, a first joint (4) is arranged outside of a first section, which is defined by the area between the two tracks (16, 17) of the first vehicle unit (1), or in a third of the first section, said third extending to the rear of the vehicle unit (1); and in the vehicle longitudinal direction, a second joint (5) is arranged outside of a second section, which is defined by the area between the two tracks (18, 19) of the second vehicle unit (2), or in a third of the second section, said third extending to the nose of the second vehicle unit (2). In order to facilitate a skid steering, the first drive system (6, 8, 9, 10) is designed to operate the tracks (16, 17) of the first vehicle unit (1) independently of each other with respect to speed, and the crawler vehicle has control means which are designed to operate the tracks (16, 17) of the first vehicle unit (1) in a speed-controlled manner on the basis of a steering requirement.

Description

Electrified steering and drive system with lateral wheel steering

The invention relates to a tracked vehicle with a first vehicle unit with two tracks and a first drive system, set up for lateral wheel steering of the first vehicle unit, with a second vehicle unit with two tracks and with a coupling element which mechanically connects the two vehicle units, with the tracks of the first vehicle unit and the second vehicle unit caterpillars, in particular caterpillar tracks or rubber tracks.

In order to make larger tracked vehicles more maneuverable or to create greater modularity, it is known in the prior art to subdivide them into two vehicle units. In this case, a vehicle unit at the front in the direction of travel and a vehicle unit at the rear with a similar contour are connected in an articulated manner.

In the front vehicle unit, in which generally a drive of the crawler vehicle is installed, seats for driver and passenger are provided. Furthermore, the front vehicle unit preferably has additional usable space that can be used for transport tasks. Usable space is generally also available in the rear vehicle unit.

To drive such crawler vehicles, engine power is generally distributed to the front first vehicle unit and the rear second vehicle unit by means of a transfer case. In each in-vehicle unit, drive power is symmetrically transmitted to both tracks, so that a crawler speed of the respective tracks is substantially identical. A differential may be present but is often omitted for cost reasons.

Such tracked vehicles are generally steered by means of hydraulic cylinders, which pivot the rear, second vehicle unit against the front, first vehicle unit about a joint. Such steering is also called articulated steering, and a crawler vehicle with such steering is correspondingly an articulated crawler vehicle. The drive power is transmitted from the front, first vehicle unit to the rear, second vehicle unit via a connecting shaft that is routed through the joint.

Such an articulated crawler vehicle is known, for example, from document DE 102 00 901 44 01 A1 or also from document WO 2011/049509 A1. An advantage of such vehicles is the combination of maneuverability and transport volume. By dividing the two driven and mutually connected, relatively small vehicle units, the transport volume of a large tracked vehicle is combined with the maneuverability of a smaller tracked vehicle. Combined with wide tracks and low weight, it can drive on types of terrain and transport goods over which no other vehicle can otherwise drive.

US Pat. No. 4,645,023 A discloses an articulated crawler vehicle with two vehicle units and a coupling unit which connects the two vehicle units to one another and can set a rotational movement of a vehicle unit relative to the coupling unit by means of various actuators.

It is an object of the invention to provide an improved tracked vehicle having two vehicle units. In particular, it is an object of the invention to improve the driving behavior of such a tracked vehicle.

This object is solved by the teaching of the independent claims. The advantageous developments are claimed in the dependent claims.

A first aspect of the invention relates to a tracked vehicle, which has a first vehicle unit with two lanes and a first drive system, set up for wheel-side steering of the first vehicle unit, and a second vehicle unit with two lanes, with a coupling element mechanically connecting the two vehicle units binds and has two joints. In addition, the coupling element preferably has a coupling rod which connects the two joints to one another.

The tracks of the first vehicle unit and the second vehicle unit preferably have caterpillars, in particular caterpillar tracks or rubber tracks. A first joint in the vehicle front-rear direction is preferably arranged outside a first portion defined by the space between the two lanes of the first vehicle unit or in a third of the first portion extending to a rear of the first vehicle unit, and a second joint is further preferably arranged in the vehicle front-rear direction outside a second portion defined by the space between the two lanes of the second vehicle unit or in one third of the second portion extending to a front of the second vehicle unit. The first joint and the second joint are preferably spaced apart and each have at least one vertical axis of rotation.

To implement lateral wheel steering, the first drive system is set up to operate the tracks of the first vehicle unit independently of one another's speed, the tracked vehicle having control means which are set up to operate the tracks of the first vehicle unit with speed control depending on a steering request.

The second aspect of the invention relates to a method for operating a caterpillar vehicle, wherein for a right turn in the direction of travel a differential speed between the left lane and the right lane of the first vehicle unit is set, in which the left lane runs faster than the right lane, with a left turn in the direction of travel, a differential speed between the right lane and the left lane of the first vehicle unit is set, in which the left lane runs slower than the right lane, and where both lanes are operated at least essentially at the same speed for driving straight ahead. This assumes driving on level ground with the same surface.

A side wheel steering in the sense of the invention steers by driving one track at a different speed than the other track. A drive system for lateral steering drives the curve-outside track at a higher speed than the curve-inside track when cornering and thus takes on the steering function of the vehicle in addition to the drive task.

The invention is based on the approach of granting the two vehicle units more degrees of freedom in the movement to one another in a tracked vehicle with two vehicle units. For this purpose, according to the invention, a coupling element is preferably provided which has two joints which are spaced apart from one another. By providing the spaced-apart joints, a rear vehicle unit in the direction of travel can follow a trajectory following the front vehicle unit, which has fewer buckling points than in the case of a coupling element with only a single joint. Here, in particular, fewer transverse forces act on the first vehicle unit and the second vehicle unit. A trajectory, with which the second vehicle unit follows the first vehicle unit, preferably has no break points at all.

By preferably arranging the joints outside the space formed between the two lanes of the respective vehicle unit or at least in a third of a section of this space facing the other vehicle unit, better handling of the two vehicle units is achieved. The coupling element according to the invention acts through the position of the two Ge steer this similar to a drawbar of a trailer. As a result, greater maneuverability is achieved than with two-part crawler vehicles with only one joint.

Compared to an articulated crawler vehicle with articulated steering, the crawler vehicle according to the invention achieves a much more stable driving behavior when steering, because the two vehicle units are not actively bent towards one another. In addition, the driving behavior when steering compared to such articulated steering does not depend, or only to a small extent, on the existing ground or the coefficient of friction of the individual driving units to the ground.

Compared to a caterpillar vehicle with articulated steering, the caterpillar vehicle according to the invention can also be operated at a significantly higher speed. A wear of the caterpillars, in particular with rubber caterpillars, by a sideways pivoting of the vehicle units, as it is the case in the caterpillar vehicle with articulated steering, can be avoided due to the higher degree of freedom of movement of the vehicle units relative to one another. By providing lateral wheel steering, the efficiency of the drive system when cornering can also be significantly improved, since mechanical or electrical regeneration is possible. A steering torque for the two vehicle units is not created by an active buckling, but by a speed difference on the inside and outside of the curve Sense. As a result, the slip on the respective track can be kept small compared to crawler vehicles with an articulated joint.

The coupling element preferably has a rigid coupling rod between the two joints. An optimal length of such a connecting rod is measured as a function of a geometry of both vehicle units, in particular the length and the track width. Rigid here means that the coupling rod is not deformable in terms of mechanics. However, it goes without saying for a person skilled in the art that this only applies up to a defined load limit and that such a rod still has a certain elasticity.

In an advantageous embodiment of the tracked vehicle, the second vehicle unit has a second drive system, which drives the second vehicle unit independently of the drive of the first vehicle unit by the first drive system and is also set up for side wheel steering of the second vehicle unit. By providing a second drive system in the second vehicle unit, the drive power can be distributed to both vehicle units. In addition, the second vehicle unit can be steered deeply with the first vehicle unit and thus contribute to better handling when steering the tracked vehicle.

In a further advantageous embodiment of the tracked vehicle, the first joint is arranged outside of the first vehicle unit, in particular directly on the outside of the first vehicle unit and/or the second joint is arranged outside of the second vehicle unit, in particular directly on the outside of the second vehicle unit. In this way, restrictions on the structure of the vehicle units can be avoided by providing pivoting space for the coupling element. A rod of the coupling element, which connects the two joints to one another, can then pivot essentially in all spatial directions outside of the vehicle units.

In a further advantageous embodiment of the tracked vehicle, the first joint is arranged approximately or exactly on a central axis of the first vehicle unit and the second joint is arranged approximately or exactly on a central axis of the second vehicle unit. This results in a particularly advantageous driving behavior with a symmetrical tension distribution. In particular, there is no torque on the vehicle units around the vehicle's center of gravity.

In a further advantageous embodiment of the tracked vehicle, the first drive system and/or the second drive system are each operated electrically and supplied with electrical power from a primary energy source, in particular an internal combustion engine, a battery or a fuel cell or any combination of these three primary energy sources. In this way, a particularly flexible drive system is realized, which is particularly suitable for side wheel steering.

In a further advantageous embodiment of the tracked vehicle, only one primary energy source is arranged in the first vehicle unit or in the second vehicle unit and supplies both its own vehicle unit and the other vehicle unit with electrical power. As a result, a particularly space-saving concept is realized.

In a further advantageous refinement, the second drive system is set up to operate the tracks of the second vehicle unit independently of the speed of one another and independently of the speed of the tracks of the first vehicle unit, with the tracked vehicle having control means which are set up to regulate the speed of the tracks of the second vehicle unit as a function of a steering request to operate. In this way, in particular, lateral wheel steering can be implemented, as well as control assistance from the second vehicle unit when steering.

In a further advantageous embodiment of the tracked vehicle, the first drive system and/or the second drive system has drive elements for the crawler tracks or for rubber tracks, a transfer gear and two drive shafts, with a first drive shaft having a drive element of one track and a first electric machine of the torque transmission is or can be connected and a second drive shaft is connected or can be connected in a torque-transmitting manner to a drive element of the other track and a second electric machine of the torque transmission, both drive shafts being or being connectable to the transfer gear in a torque-transmitting manner, and one element of the transfer gear being connected to a third Electric machine torque-transmitting connected or connectable. By providing a transfer gear, a braking performance of one of the curves inside Track can be mechanically recuperated by mechanically transferring it to the outer track.

In a further advantageous embodiment of the tracked vehicle, this control means is set up to transfer braking power mechanically from a curve inner track at least partially as regenerative drive power to a curve outer track of the first vehicle unit between the braking power from a curve inner track mechanically at least partially as to transmit regenerative drive power to an outside lane of the second vehicle unit. As a result, a particularly energy-efficient drive can be implemented.

In a further advantageous embodiment of the tracked vehicle, the first joint and/or the second joint has three degrees of freedom and can be pivoted about two orthogonal axes and rotated about its axis. As a result, the two vehicle units can move flexibly in relation to one another in all three spatial directions.

In an advantageous embodiment of the method, depending on the type of use, either only the first vehicle unit is driven or both vehicle units are driven. As a result, the second vehicle unit can be operated flexibly in a type of trailer mode. This is particularly advantageous with regard to the energy efficiency of the tracked vehicle.

In a further advantageous embodiment of the method, a differential speed between the left lane and the right lane in the direction of travel of the second vehicle unit is generated for cornering on the basis of the speeds of the lanes of the first vehicle unit in such a way that the second vehicle unit initiates a steering maneuver of the first vehicle unit supported and follows the first vehicle unit, so that countersteering or swerving is avoided. This enables a particularly advantageous driving behavior when steering the tracked vehicle.

In a further advantageous embodiment of the method, a required drive power is divided between the first vehicle unit and the second vehicle unit. In this way, particularly good traction can be achieved.

In a further advantageous embodiment of the method, the second vehicle unit is pulled by the first vehicle unit when idling or is operated in such a way that for a right turn in the direction of travel a difference in speed between the left lane and the right lane of the second vehicle unit is set, in which the left lane runs faster than the right lane, and for a left turn in the direction of travel a difference in speed between the right lane and the left lane the second vehicle is set convincing unit, in which the left lane runs slower than the right lane, and for straight driving - both lanes are operated at least substantially at the same speed - on the level with the same ground. Here, the second vehicle unit follows the first vehicle unit on a particularly advantageous trajectory and supports the first vehicle unit in steering the caterpillar vehicle.

Further features and advantages result from the following description in connection with the figures. They show at least partially schematically:

FIG. 1 shows an exemplary embodiment of a tracked vehicle with two vehicle units which are connected by a coupling element;

FIG. 2 shows a plan view of a tracked vehicle according to FIG. 1 in a sectional view;

Figure 3 is a plan view of one of the vehicle units; and

FIG. 4 shows an exemplary embodiment of a method for operating a crawler vehicle.

Figure 1 shows a tracked vehicle with a first vehicle unit 1 and a second vehicle unit 2, both of which tracks 17, 19 have caterpillars, i.e. rubber tracks or metal tracks. The two vehicle units 1, 2 are mechanically connected by a coupling element 3, 4, 5.

FIG. 2 shows a caterpillar vehicle according to FIG. 1 when cornering, which is initiated by the vehicle unit 1 in front of it.

The first front vehicle unit 1 has a first lane 16, which is arranged on the right in the direction of travel, and a second lane 17, which is arranged on the left in the direction of travel. Correspondingly, the second vehicle unit 2 has a first track 18, which is arranged on the right in the direction of travel, and a second track 19, which is in the direction of travel is arranged on the left. The tracks 16, 17, 18, 19 preferably have a rubber chain or a metal chain as drive elements.

Both vehicle units 1, 2 can be steered independently of one another by means of side wheel steering. This is realized in that a first electric motor 8, 11 and a second electric motor 10, 13 can drive the two tracks of the respective vehicle unit 1, 2 independently of one another. Preferably, the two vehicle units 1, 2 each have a transfer gear 6, 7. More preferably, only the first vehicle unit 1 can have such a transfer gear 6 . The one or more transfer gears 6, 7 are further preferably coupled to a third electric machine 9, 12. This allows a torque flow between the two tracks 16, 17; 18, 19 of a respective vehicle unit 1; 2 to be realized. In particular, a regenerative drive power can be transmitted as drive power by means of such an arrangement when cornering from the inner track 16, 18 to the outer track 17, 19. Furthermore, a more balanced load distribution between the electric machines of a vehicle unit 1; 2 can be achieved.

Preferably, only one of the two vehicle units 1; 2 via a power source and supplies the second in-vehicle unit 1; 2 by means of a particularly flexible cable or pipe with energy. A fuel cell, a generator, a compressed air reservoir and/or a battery or a combination of these energy sources can be used as the energy source.

The first vehicle unit 1 and the second vehicle unit 2 are preferably mechanically connected via a coupling element which has a first joint 4 and a second joint 5 . The coupling element also has a preferably rigid coupling rod 3 which extends between the two joints 4 and 5 .

The provision of two joints 4, 5 offers improved manoeuvrability, in particular in comparison to the prior art with an articulated steering control element. Furthermore, the typical disadvantages of articulated steering of tracked vehicles, such as poor efficiency and high track wear, are significantly improved.

The optimal length of the connecting rod is dependent on the geometry of both vehicle units 1, 2, in particular on their length and track width. Preferably, all four lanes 16,17,18,19 are individually speed controlled in the illustrated embodiment. In addition, the torque applied to each of the four chains can preferably be adjusted. When steering, the chains are therefore driven at different speeds. The steering torque for the respective vehicle unit is therefore not created by active bending as in the case of an articulated steering control element from the prior art, but by the torque difference on the inside and outside tracks of the curve.

Thanks to the individually adjusted speeds during steering, the transverse forces and the slip on the respective chain can be kept relatively low compared to the prior art, efficiency can be increased, chain wear reduced and handling improved.

A further increase in efficiency and improvement in driving behavior is made possible by the coupling rod 3 . For this purpose, it is particularly advantageous if the two joints 4, 5 have three degrees of freedom, so that the coupling rod 3 can be multi-dimensionally bent and twisted relative to the vehicle units 1, 2. A possible design for these joints are e.g. rotatable cardan joints.

Furthermore, it is advantageous if the position of the two joints 4, 5 is not in the vicinity of the respective center of gravity or lane center of the respective vehicle unit 1, 2. This ensures that a sufficient steering torque can be transmitted between the two vehicle units 1 , 2 when cornering. This causes a largely automatic tracking of the rear second vehicle unit 2 to the front first vehicle unit 1 if vehicle unit 2 is towed. As a result, the steering torque for the rear second vehicle unit 2, which must be applied by the local drive 22, can be reduced and the components can be dimensioned correspondingly smaller. When reversing, this also applies accordingly to the drive 21 of the first vehicle unit 1 that is then at the rear.

It is also possible to switch off the drive 22 of the rear vehicle unit 2 or to pull this vehicle unit along when cornering. This can, for example, enable particularly efficient operation of the tracked vehicle when driving on the road. As shown in Fig. 3, the joints 4, 5 are preferably located outside of the vehicle units 1, 2. With such an arrangement, the geometry of the vehicle units 1, 2, for example their “cabin structure”, does not have to be adapted and can be modified from existing ones Realizations of caterpillar vehicles are taken over. In this way, the original intended use of such vehicles can be retained unchanged, but the weak points inherent in the system of the designs according to the prior art are solved. Furthermore, the joints 4, 5 are preferably located on a central axis 20 of the vehicle units 1, 2. This ensures a balanced power transmission between the two vehicle units 1, 2.

In Fig. 2, the crawler vehicle performs a steering maneuver. This is initiated in the front vehicle unit 1 by means of a difference in speed between the right lane 16 and the left lane 17 . The tracked vehicle then swivels around a vertical axis, the position of which is determined by the combination of steering angle and driving speed. The hinge point 4 of the first vehicle unit 1 pivots out of the ideal curved path 14 . Depending on how the steering angle varies, the articulation point 4 of the first vehicle unit 1 describes a curve 15 which corresponds to a higher-order polygon with a singularity point (the point at which the curve 15 begins to deviate from the ideal curved path 14). If the coupling rod 3 were not present, the articulation point formed by the second articulation 5 would have to follow the articulation point formed by the first articulation 4 and thus the curve 15 directly. Depending on the geometry of the rear, second driving unit 2, this can lead to greatly varying speed requirements on its tracks 18, 19, which are difficult to control and cause increased chain wear. Undesirable counter-steering of the rear vehicle unit 2 can also be the case.

Through the two joints 4, 5, a steering torque can be transmitted between the two vehicle units 1, 2 when cornering. As a result, tracking of the rear vehicle unit 2 can be achieved. The two joints 4, 5, which are connected to the coupling rod 3, namely cause the curved path of the articulation point formed by the second joint 5 does not follow the curve 15, but a smoothed curve that lies between the ideal curved path 14 and the curve 15 lies. This leads to significantly smoother and easier to control speed requests to the lanes 18, 19 of the second vehicle unit 2. A counter-steering, or a sideways shift of the rear vehicle unit 2, as is the case with the prior art, for example, can be prevented.

Figure 4 shows an embodiment of a method 100 for operating a tracked vehicle with two vehicle units 1, 2.

Two different driving modalities are to be considered when operating 101 the caterpillar vehicle: a) only the front vehicle unit 1 is driven b) both vehicle units 1 , 2 are driven

In the first case considered a), only the front vehicle unit 1 is driven. The Ge transmission unit 7 of the rear vehicle unit 2 is decoupled from the rear tracks 18,19. Such a driving mode can be used specifically when driving on paved roads or paths and high off-road mobility is not required, but high economy is required.

In this driving modality, the drive 22 of the second vehicle unit 2 is idling 103-N both in a right turn 102-R, in a left turn 102-L and when driving straight ahead 102-G. This is realized in particular via the transfer gear 7 and/or various clutches (not shown).

In the second driving modality b), the rear vehicle unit 2 is also driven. This driving mode is primarily used when high off-road mobility and/or high traction are required. Here the drive power can be divided between the two vehicle units 1 , 2 depending on the requirement.

If a right turn is made in this case, a difference in speed between the left lane 19 and the right lane 18 of the second vehicle unit 2 is set 103-R in the direction of travel, in which the left lane 19 runs faster than the right lane 18 If a left turn is made, a differential speed between the right lane 18 and the left lane 19 of the second vehicle unit 2 is set 103-L in the direction of travel, at which the left lane 19 runs slower than the right lane 18. Both are used for driving straight ahead Traces at least essentially with the same Speed operated 103-G. This is based on a trip on the level with the same sub-ground.

It should be noted that the exemplary embodiments described are only examples that are not intended to limit the scope, applications and structure in any way. Rather, the above description gives the person skilled in the art a guideline for the implementation of at least one exemplary embodiment, with various changes, particularly with regard to the function and arrangement of the components described, being able to be made without departing from the scope of protection as it is from the claims and these equivalent combinations of features.

List of references first vehicle unit second vehicle unit

Coupling rod first joint second joint, 7 transfer gear, 9, 10 electric machine 1, 12, 13 electric machine 4 cam track 5 cam 6, 18 first track 7, 19 second track 0 central axis 1, 22 drive

Claims

patent claims

A tracked vehicle comprising: a first vehicle unit (1) having two tracks (16, 17) and a first drive system (6, 8, 9, 10); a second vehicle unit (2) having two lanes (18, 19); a coupling element which mechanically connects the two vehicle units (1, 2) and has two joints (4, 5) and a coupling rod (3), the coupling rod (3) mitei the two joints (4, 5) at a defined distance Nander connects and the first joint (4) and the second joint (5) each have at least one vertical axis of rotation; wherein the tracks of the first vehicle unit (1) and the second vehicle unit (2) have caterpillar tracks, in particular crawler tracks or rubber tracks, wherein a first joint (4) in the longitudinal direction of the vehicle outside a first section which extends through the space between the two tracks (16, 17) of the first vehicle unit (1), or is arranged in a third of the first section, which extends to a rear of the first vehicle unit (1), with a second joint (5) in the vehicle longitudinal direction outside a second section, which is defined by the space between the two tracks (18, 19) of the second vehicle unit (2), or is arranged in a third of the second section, which extends to a bow of the second vehicle unit (2), characterized in that that the first drive system (6, 8, 9, 10) for a wheel side steering of the first vehicle generating unit (1) is set up, and is set up to the tracks (16, 17) of the first vehicle ug unit (1) speed to operate independently, the tracked vehicle having control means which are set up to operate the tracks (16, 17) of the first vehicle unit (1) speed-controlled depending on a steering request.

2. Tracked vehicle according to claim 1, wherein the second vehicle unit (2) has a second vehicle unit (7, 11, 12, 13) which drives the second vehicle unit (2) independently of the drive of the first vehicle unit (1) by the first Drive system (6, 8, 9, 10) drives and is also set up for lateral wheel steering of the second vehicle unit (2).

3. Tracked vehicle according to claim 1 or 2, wherein the first joint (4) is arranged outside the first vehicle unit (1), in particular directly on the outside of the first vehicle unit (1) and/or wherein the second joint (5) is outside the second Vehicle unit (2), in particular directly on the Au outside of the second vehicle unit (2) is arranged.

4. Tracked vehicle according to one of the preceding claims 1 to 3, wherein the first joint (4) is arranged approximately or exactly on a central axis (20) of the first driving tool unit (1) and the second joint (5) approximately or exactly a central axis of the second vehicle unit (2) is arranged.

5. Tracked vehicle according to one of the preceding claims 1 to 4, wherein the first drive system (6, 8, 9, 10) and / or the second drive system (7, 11, 12, 13) is each electrically operated and from a primary energy source, in particular an internal combustion engine, a battery or a fuel cell or any combination of these three primary energy sources, are supplied with electrical power.

6. Tracked vehicle according to claim 5, wherein the primary energy source is arranged in the first vehicle unit (1) or in the second vehicle unit (2) and the respective other vehicle unit (1; 2) also provides electrical power.

7. Tracked vehicle according to one of the preceding claims 1 to 6, wherein the second drive system (7, 11, 12, 13) is set up, the tracks (18, 19) of the second vehicle unit (2) speed-independent of each other and speed-independent of the tracks ( 16, 17) of the first vehicle unit (1), the tracked vehicle having control means which are set up to operate the tracks (18, 19) of the second vehicle unit (2) in a speed-controlled manner as a function of a steering request. 8. Tracked vehicle according to one of the preceding claims 1 to 7, wherein the first drive system (6,

8, 9, 10) and/or the second drive system (7, 11, 12, 13) in each case drive elements (8,9,10,11, 12,13) for the track chains or for rubber chains, a transfer gear (6; 7 ) and has two drive shafts, a first drive shaft being connected or connectable in a torque-transmitting manner to a drive element of one track (17; 19) and a first electric machine (10; 13), and a second drive shaft being connected to a drive element of the other track (16; 18 ) and a second electric machine (8; 11) is connected or can be connected in a torque-transmitting manner, both drive shafts being connected or connectable in a torque-transmitting manner to the transfer gear (6,7), and an element of the transfer gear (6,7) being connected to a third electric machine ( 9; 12) is connected or can be connected in a torque-transmitting manner.

9. Tracked vehicle according to one of the preceding claims 1 to 8, which has control means set up to transfer braking power mechanically from a curve-inner lane of the first vehicle unit (1) at least partially as regenerative drive power to a curve-outer lane of the first vehicle unit (1) and/or or mechanically at least partially transfer braking power from a lane on the inside of the curve of the second vehicle unit (2) as regenerative drive power to a lane on the outside of the curve of the second vehicle unit (2).

10. Tracked vehicle according to one of the preceding claims 1 to 9, wherein the first joint (4) and / or the second joint (5) has three degrees of freedom and is pivotable about two orthogonal axes and is rotatable about its axis.

11. Method (100) for operating (101) a tracked vehicle according to one of the preceding claims, wherein a differential speed between the left lane (17) and the right lane (16) of the first vehicle unit (1) is set for a right turn in the direction of travel (102-R), in which the left lane (17) runs faster than the right lane (16), with a differential speed between the right lane (16) and the left lane (17) of the first vehicle unit for a left turn in the direction of travel (1) is set (102-L), in which the left lane (17) runs slower than the right-hand lane (16), and both lanes are operated at least essentially at the same speed for driving straight ahead (102-G).

12. The method according to claim 11, wherein, depending on the type of use, either only the first vehicle unit (1) is driven or both vehicle units (1,

2) be driven.

13. The method (100) according to claim 11 or 12, wherein, for cornering, a differential speed between the left lane (19) and the right lane (18) in the direction of travel of the second vehicle unit (2) based on the speeds of the lanes ( 16, 17) of the first vehicle unit (1) is generated (103-R, 103-N) in such a way that the second vehicle unit (2) supports a steering maneuver of the first vehicle unit (1) and follows the first vehicle unit (1). , so that countersteering or shearing out is avoided.

14. The method (100) according to any one of claims 11 to 13, wherein a required drive power between the first vehicle unit (1) and the second vehicle unit (2) is divided.

The method (100) according to any one of claims 11 to 14, wherein the second vehicle unit (2) is towed (103-N) by the first vehicle unit (1) when idling or operated in such a way that it is for a right turn a differential speed between the left lane (19) and the right lane (18) of the second vehicle unit (2) is set (103-R) in the direction of travel, at which the left lane (19) runs faster than the right lane (18), and for a left turn in the direction of travel, a differential speed between the right lane (18) and the left lane (19) of the second vehicle unit (2) is set (103-L), at which the left lane (19) runs slower than the right Lane (18), and where both lanes are driven at least essentially at the same speed for driving straight ahead (103-G).