TRACKED VEHICLE

Abstract

The present invention relates to a tracked vehicle comprising at least two drivable crawler chains, a sensor device for detecting the actual speed of each of the at least two crawler chains, and a control device for controlling the driving speeds of the at least two crawler chains, wherein the control device includes a curve control module for adjusting different driving speeds for the at least two crawler chains for cornering in dependence on a steering signal of a steering signal transmitter. According to a first aspect it is proposed that with an individual drive of the at least two crawler chains the still operable other drive motor no longer follows the target rotational speed specified for the normal operation upon failure of a drive motor, but follows the sensorially detected chain or drive train speed of the failed drive by taking account of the steering signal and of the speed difference between the left and right chain sides, which is needed for the commanded curve.

Claims

1. A tracked vehicle comprising: at least two crawler chains each configured to be driven by at least one separate drive; a sensor device configured to detect the actual speed of each of the at least two crawler chains; at least one control device configured to control the driving speed of the drives, wherein the control device comprises a curve control module configured to adjust different driving speeds for the at least two crawler chains for cornering in dependence on a steering signal of a steering signal transmitter, wherein the curve control module comprises a failure control module configured to control a first drive of a first crawler chain upon failure of a second drive of a second crawler chain, wherein the failure control module is configured to control the first drive in dependence on the actual speed of the second crawler chain, and to control the actual speed of the second crawler chain in dependence on the steering signal in such a way that the crawler chains have the differential speed each required for the steering signal.

2. The vehicle of claim 1, wherein the sensor device comprises speed sensors configured to detect the actual rotational speed of a sprocket of each of the at least two crawler chains and/or the driving speed of the drives.

3. The vehicle of claim 1, wherein the drives each comprise an electric drive motor, and wherein the drive motors are each configured to be actuated by a separate converter, wherein the converters are configured to be actuated individually by the curve control module and a failure control module of the curve control module.

4. The vehicle of claim 1, wherein the curve control module is configured to take account of a driving speed signal of a driving speed controller and/or control module and actuate the converters in dependence on the driving speed signal when the first and second drives are operable, while the failure control module is configured to ignore the driving speed signal for the actuation of the converter of the first drive upon failure of the second drive, and observe the actual speed signal of the sensor device.

5. The vehicle of claim 1, wherein the drives are configured to be supplied with electric energy by a generator configured to be driven by an internal combustion engine, wherein the curve control module and/or the failure control module is/are configured to brake the first drive upon failure of the second drive, and operate the first drive by a generator, wherein a braking resistor in the power supply circuit between at least one of the drives and the generator and/or via the generator on the internal combustion engine is configured to support a regenerative current.

6. The vehicle of claim 1, wherein a braking device comprising a mechanical brake for each of the crawler chains is associated with the two crawler chains, wherein the mechanical brakes are configured to be actuated by the failure control module upon failure of a drive in dependence on the measured actual speeds of the two crawler chains and in dependence on the steering signal.

7. A tracked vehicle comprising: at least two crawler chains configured to be driven by a central drive via a superimposed steering transmission comprising two planetary gear sets comprising two first sun gears synchronized with each other and configured to be driven by the central drive, and wherein the transmission comprises a planet carrier in drive connection with a sprocket of one of the crawler chains, and wherein the transmission comprises ring gears configured to be driven in mutually opposite directions by a steering drive, further comprising a control device configured to control the drive speed of the central drive and a curve control module for actuating the steering drive in dependence on a steering signal of a steering signal transmitter, further comprising a braking device comprising one mechanical brake each for each of the crawler chains, wherein the curve control module comprises a failure control module configured to actuate the braking device upon failure of the steering drive and/or upon failure of a drive side of the superimposed steering transmission, wherein the failure control module is configured to actuate at least one of the mechanical brakes in dependence on the actual speed of at least one of the two crawler chains detected by the sensor device, and in dependence on the steering signal such that the crawler chains have the different actual speeds required for the steering signal.

8. The vehicle of claim 7, wherein the failure control module is configured to actuate the mechanical brake of at least one of the at least two crawler chains such that the actual speeds detected for the crawler chains in relation to each other correspond to the steering signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The invention will subsequently be explained in detail with reference to preferred exemplary embodiments and associated drawings. In the drawings:

[0032] FIG. 1: shows a schematic representation of a tracked vehicle comprising individual drives, which each include an independently actuatable electric motor for driving the tumbler of each crawler chain, and

[0033] FIG. 2: shows a schematic representation of the central drive of a tracked vehicle whose central drive motor drives the two tumblers of the two crawler chains via a superimposed steering transmission.

DETAILED DESCRIPTION

[0034] As shown in FIG. 1, the tracked vehicle 1 can include one crawler chain 2 and 3 each on the right and left of the vehicle body or chassis, which crawler chains can be guided so as to be endlessly circulating over a plurality of sprockets and together form the traveling gear of the tracked vehicle 1. The crawler chains 2, 3 can be configured differently depending on the type of the tracked vehicle, for example in the form of a steel link chain, a plastic and/or rubber profile chain or also a profile bar chain which is used for example to level ski slopes.

[0035] As is furthermore shown in FIG. 1, each of the crawler chains 2 and 3 is driven by a tumbler 4 which circumferentially engages with the inside of the respective crawler chain 2 and 3 and can rotatorily be driven about its axis of rotation, which can be arranged horizontally at right angles to the direction of travel.

[0036] FIG. 1 shows an individual drive in which each tumbler 4 can be driven by its own drive motor 5, wherein the output shaft of the drive motors 5 can be arranged coaxially to the tumbler axis or also offset therefrom in parallel, in particular when a transmission for example in the form of a countershaft transmission with one or two or also more gears is interposed between drive motor 5 and tumbler 4. As shown in FIG. 1, the two tumblers 4 of the two crawler chains 2 and 3 can be arranged coaxially to each other, wherein in this case the drive motors 5 advantageously can also be arranged coaxially to each other, in particular with the motor shafts aligned transversely to the direction of travel. In principle, however, it is also possible to arrange the tumblers 4 offset from each other in the direction of travel, in particular also when the crawler chains 2 and 3 are arranged at the same height in the direction of travel, for example due to the fact that the one tumbler 4 is arranged at the rear end of the one crawler chain and the other tumbler 4 is arranged at the front end of the other crawler chain.

[0037] Furthermore, it would also be possible to arrange the drive motors 5 with their motor shafts transversely to the drive axle of the tumblers 4, for example via an angled step at right angles to the drive axle or offset in parallel via a spur gear stage.

[0038] The drive motors 5 advantageously can be electric motors, wherein in principle, however, a hydraulic motor might also be considered, and mixed hybrid forms as well.

[0039] Advantageously, each of the drive motors 5 can be actuated individually and independently of the other drive motor 5 in order to be able to independently adjust the rotational speeds of the two tumblers 4 or vary the same against each other, and correspondingly drive the crawler chains 2 and 3 at different speeds.

[0040] As shown in FIG. 1, a separate actuation module 7 can be associated with each of the drive motors 5, which in case the drive motors 5 are configured as electric motors can each comprise a converter 8 which directs the current applied to the drive motors 5.

[0041] The two converters 8 can be fed from a rectifier 9 which supplies the current generated by a generator 10 to said converters 8.

[0042] Said generator 10 can be driven by an internal combustion engine, for example a diesel engine 11, for example directly or via a transmission for example in the form of a pump transfer gearbox 12.

[0043] As is furthermore shown in FIG. 1, the power supply circuit to which the electric motors 5 are connected furthermore can comprise a braking resistor 13, for example in the form of a grid box, in order to be able to brake the drive motors 5 and, in the generator mode of the drive motors 5, to be able to thermally decompose regenerative energy at said braking resistor 13. As explained already, a braking torque generated at the drive motors 5 for braking the same might also be supported via the generator 10 and the internal combustion engine 11 connected thereto.

[0044] The rotational speeds of the drive motors 5 can be varied against each other and be adjusted individually by the two converters 8, which in particular can be utilized for driving curves with the tracked vehicle 1 by one crawler chain circulating faster than the other crawler chain.

[0045] The electronic control device 14, which for example can comprise a microprocessor, a memory module with software deposited therein, and further hardware modules, therefor can actuate the power electronics to which the drive motors 5 are connected, in particular via said converters 8.

[0046] As shown in FIG. 1, said control device 14 can comprise a curve control module 15, which on its input side receives a steering signal from a steering device 16, via which a vehicle operator can enter his steering wish. Such a steering device can comprise a classical steering wheel, but also a joystick or other handlebar configurations. For example, the steering device 16 can include a steering angle detector which detects the lock angle of a steering wheel and provides a steering signal proportional to the lock angle, which then is processed by the curve control module 15 in order to generate corresponding, in particular different driving speeds at the drive motors 5 so that the crawler chains 2 and 3 move differently fast.

[0047] Furthermore, said control device 14 comprises a speed control module 17 which controls or regulates the driving speed of the tracked vehicle 1 and provides a driving speed signal to the power electronics, in particular to said converters 8, in order to operate the drive motors 5 with a corresponding torque and/or a corresponding speed. Said driving speed control module 17 can comprise a driving speed wish lever, for example in the form of an accelerator pedal or a joystick, in order to enable the vehicle operator to indicate a driving speed wish, depending on which—by taking account of the power reserves—the drive motors 5 then are actuated via said converter 8 and implement the driving speed wish.

[0048] In conjunction with the aforementioned curve control module 15, the speed control signal of the driving speed controller can be implemented as a basic control signal and upon entry of a curve or steering angle wish can then be modified for the right and left drive motors in order to adjust different chain speeds on the right and left while basically implementing the desired driving speed, which provides for cornering.

[0049] When one of the drive motors 5 fails, said control device 14 switches into a failure mode in which the actuation of the drive motors 5 is changed.

[0050] In particular upon failure of one of the drive motors 5, a failure control module 18 is activated, which can be part of the electronic control device 14 and actuates the still operable drive motor 5 in such a way that despite the failed drive motor, the desired curve radius is maintained or maintained as far as possible.

[0051] For this purpose, the tracked vehicle 1 comprises a redundantly designed sensor device 19 that detects the actual speed of each crawler chain 2 and 3, which can be accomplished directly or indirectly. For example, the sensor device 19 can comprise a pair of speed sensors 20 which detect the rotational speeds of the two tumblers 4 and/or the rotational speeds of the output shaft of the intermediate transmissions 6 in the form of the described lateral countershafts. Alternatively or in addition, said sensor device 19 can also comprise chain speed sensors 21 which detect the circulation speed of the crawler chains 2 and 3.

[0052] Hence, if one of the two drive motors 5 fails, said failure control module 18 actuates the still operable drive motor 5 in dependence on the detected actual speed of the other crawler chain, whose drive motor has failed, by taking account of the steering angle signal of the curve control module 15 or the steering device 16. In dependence on the measured actual speed of the crawler chain driven no longer, whose drive motor has failed, the circulation speed of the other crawler chain is tracked in such a way that the speed difference between the crawler chain driven no longer and the driven crawler chain leads to a curve radius which corresponds to the steering wish or said steering signal.

[0053] For this purpose, the drive motor 5 of the still operable side is actuated such that it —always following the current steering command —adjusts the rotational speed in relation to the faulty side, which is required to drive along the commanded curve —or possibly also straight ahead.

[0054] If braking of the still operable drive motor 5 is required to maintain the speed difference between the two crawler chains 2 and 3, which is necessary for cornering, said failure control module 18 can also provide regenerative braking, for example via said braking resistor 13.

[0055] The tracked vehicle 1 furthermore can also include a braking device 22 with mechanical brakes 23 for mechanically braking each of the crawler chains 2 and 3, wherein such mechanical brakes 23 for example can act on the drive shaft of the tumbler 4 or can also brake the tumbler 4 itself, wherein alternatively or in addition however a special, separate sprocket, which is in engagement with the respective crawler chain 2 or 3, can serve as braking wheel and can be braked.

[0056] If necessary, said failure control module 18 can make use of and actuate the braking device 22 in order to actuate at least one of the mechanical brakes 23 to ensure the speed difference needed for the commanded curve at the crawler chains 2 and 3.

[0057] As shown in FIG. 2, the tracked vehicle 1 can also comprise a central drive in which a central drive motor 5 drives both tumblers 4. To split up or branch the rotatory drive movement of the drive motor 5 for both tumblers 4, a superimposed steering transmission 24 can be provided, which can include a central input shaft 25 which is driven by the drive motor 5, cf. FIG. 2.

[0058] Such a superimposed steering transmission 24 can comprise two planetary gear sets 26, 27, whose sun gears 28 advantageously can be driven coaxially to each other and can be synchronized by a common drive shaft 29, cf. FIG. 2, wherein said drive shaft 29 and hence both sun gears 28 can be driven by the drive motor 5.

[0059] Each of the planet carriers 30 of the planetary gear sets 26 and 27 can drive the tumbler 4 of the right and left crawler chains 2 and 3, respectively, via one output shaft 31 each, cf. FIG. 2.

[0060] To be able to vary the driving speeds of the left and right crawler chains 2 and 3 against each other despite the central drive motor, it is provided to drive the two ring gears 32 of the planetary transmissions in mutually opposite directions, namely by a steering drive 33 which is actuated in dependence on said steering signal and is able to rotate the ring gears 32 in mutually opposite directions via a counter-rotating gear stage 34, cf. FIG. 2.

[0061] If one drive side fails, for example due to breakage of the planet carrier, or if the steering drive 33 fails, so that the tracked vehicle 1 no longer would maintain a specified curve radius, the above-mentioned failure control module is activated in order to replace or modify the “normal” actuation of the central drive motor 5 and of the steering drive 33 and to ensure cornering in a failure operating mode. For this purpose, said failure control module actuates the braking device 22 and actuates at least one of the two mechanical brakes 23 in order to ensure the speed difference of the two tumblers 4 required for the specified steering signal and the correspondingly desired curve radius. As shown in FIG. 2, the two brakes 23 can act for example on the output shaft 29 which connects the planetary transmissions 26 and 27 to the two tumblers 4.

[0062] The actuation of the braking device 22 here is effected, in conjunction with said steering signal, in dependence on the actual speeds of the two crawler chains 2 and 3 detected by the sensor device 19, wherein here for example speed sensors 20 can detect the rotational speeds of the two tumblers 4 or of said output shafts 31, cf. FIG. 2.