Steering System for a Vehicle, in Particular a Utility Vehicle

Abstract

A steering system for a vehicle, in particular a utility vehicle, has at least one first steering gear and at least one first steering mechanism for steering at least one first vehicle wheel. The first steering gear is coupled to the first steering mechanism. The steering system has at least one second steering gear and at least one second steering mechanism for steering at least one second vehicle wheel. The second steering gear is coupled to the second steering mechanism. At least one tensioning mechanism is coupled to the first steering gear and to the second steering gear such that the first steering gear and the second steering gear are pre-tensionable with respect to each other, in particular in the idle state and oppositely.

Claims

1.-12. (canceled)

13. A steering system for a vehicle, comprising: at least one first steering gear and at least one first steering mechanism for steering at least one first vehicle wheel, wherein the first steering gear is coupled to the first steering mechanism; at least one second steering gear and at least one second steering mechanism for steering at least one second vehicle wheel, wherein the second steering gear is coupled to the second steering mechanism; at least one tensioning mechanism coupled to the first steering gear and to the second steering gear such that the first steering gear and the second steering gear are pre-tensionable with respect to each other, in an idle state and oppositely.

14. The steering system as claimed in claim 13, wherein the tensioning mechanism is linked to the first steering mechanism and to the second steering mechanism.

15. The steering system as claimed in claim 13, wherein the tensioning mechanism, in a mounted state, is elastically pre-tensionable and/or pre-tensioned.

16. The steering system as claimed in claim 13, wherein the tensioning mechanism comprises at least one longitudinal adjustment mechanism and/or telescopic mechanism.

17. The steering system as claimed in claim 13, wherein the tensioning mechanism comprises at least one elastic spring.

18. The steering system as claimed in claim 17, wherein the elastic spring is an axial spring.

19. The steering system as claimed in claim 17, wherein the elastic spring is a radial spring.

20. The steering system as claimed in claim 19, wherein the radial spring is a leaf spring.

21. The steering system as claimed in claim 13, wherein the second steering gear is designed to be smaller than the first steering gear in at least one dimension.

22. The steering system as claimed in claim 21, wherein the second steering gear is designed to be at least about 10% smaller than the first steering gear in at least one dimension.

23. The steering system as claimed in claim 21, wherein the second steering gear is designed to be at least about 20% smaller than the first steering gear in at least one dimension.

24. The steering system as claimed in claim 21, wherein the second steering gear is designed to be at least about 25% smaller than the first steering gear in at least one dimension.

25. The steering system as claimed in claim 13, wherein the first steering gear is coupled to at least one first electric motor, with the second steering gear being coupled to at least one second electric motor.

26. The steering system as claimed in claim 25, wherein the second steering gear is drivable exclusively by the second electric motor.

27. The steering system as claimed in claim 13, wherein the first steering gear has at least one mechanical through-drive, via which the first steering gear is couplable to at least one steering column and to a vehicle steering wheel.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0023] The single FIG. 1 shows a schematic perspective illustration of an exemplary embodiment of a steering system according to the invention.

DETAILED DESCRIPTION OF THE DRAWING

[0024] FIG. 1 accordingly shows a steering system 10 for a vehicle (not illustrated in FIG. 1).

[0025] The vehicle is designed as a utility vehicle.

[0026] The steering system 10 comprises a first steering gear 12 and a first steering mechanism 14 for steering at least one first vehicle wheel 16.

[0027] The first steering gear 12 is furthermore coupled to the first steering mechanism 14.

[0028] The first steering mechanism 14 comprises a first steering rod 14a and a second steering rod 14, which are connected to each other via a swivel joint.

[0029] The second steering rod 14b is furthermore coupled, by means of a further swivel joint, to a track rod 14c, which in turn acts on the wheel carrier 14d for receiving and mounting the first vehicle wheel 16.

[0030] The first steering rod 14a is in turn coupled to an output shaft of the first steering gear 12 in a torsion-resistant manner.

[0031] A rotation of the output shaft of the first steering gear 12 is consequently transmitted to the first steering mechanism 14, whereby the track rod 14c thereof is pivoted, which results in a steering movement or turning of the first vehicle wheel 16.

[0032] Moreover, the steering system has a second steering gear 18 and a second steering mechanism 20 for steering a second vehicle wheel 22.

[0033] According to FIG. 1, the first steering gear 18 is coupled to the second steering mechanism 20.

[0034] The second steering mechanism 20 comprises a further first steering rod 20a and a second steering rod 20b, which are connected to each other via a swivel joint.

[0035] The second steering rod 20b is furthermore coupled, via further a swivel joint, to a further track rod 20c, which in turn acts on the wheel carrier 20d for receiving and mounting the second vehicle wheel 22.

[0036] The further first steering rod 20a is coupled to an output shaft of the second steering gear 18 in a torsion-resistant manner.

[0037] A rotation of this output shaft of the second steering gear 18 is consequently transmitted to the second steering mechanism 20 in such a way that the track rod 20c is pivoted, which results in a steering movement or turning of the second vehicle wheel 22.

[0038] The first and second steering gear 12, 18 are each fastened to a vehicle frame support (e.g. via a plurality of screw connections), wherein the output shaft of both steering gears 12, 18 extends through the vehicle frame support in each case and is coupled to the respective first steering rod 14a, 20a in a torsion-resistant manner.

[0039] In the present exemplary embodiment, the first and second vehicle wheel 16, 22 or the steering system 10 are associated with a front axle 24 of a utility vehicle.

[0040] Alternatively or additionally, the first and second vehicle wheel 16, 22 or the steering system 10 may also be associated with a rear axle of a utility vehicle.

[0041] The steering system furthermore has a tensioning mechanism 26, which is coupled to the first steering gear 12 and to the second steering gear 18.

[0042] According to FIG. 1, the tensioning mechanism may be designed as an elastically pre-tensionable and/or pre-tensioned tension rod, tie rod, tensioning strut, draw tube, tie beam or vise.

[0043] This coupling is realized in such a way that the first steering gear 12 and the second steering gear 18 are pre-tensionable with respect to each other.

[0044] In particular, it may be provided that the first steering gear 12 and the second steering gear 18 are pre-tensionable with respect to each other in the idle 18 state and oppositely.

[0045] The tensioning mechanism 26, in the mounted state, is therefore elastically pre-tensionable or may be pre-tensioned.

[0046] Moreover, the tensioning mechanism 26 is linked to the first steering mechanism 14 and to the second steering mechanism 20.

[0047] According to FIG. 1, the link is realized at the swivel joint between the second steering rod 14b, 20b and the respective track rod 14c, 20c in each case.

[0048] An opposite pre-tension means that, at the swivel joint between the second steering rod 14b, 20b and the respective track rod 14c, 20c in each case, the first and second steering mechanism 14, 20 are pressed apart elastically by the tensioning mechanism 26 by the amount for compensating or eliminating the steering play of the steering system 10.

[0049] In this case, the spacing between the two track rods 14c, 20c increases, amongst other things, at the swivel joint of the two second steering rods 14b, 20b in such a way that the steering play is removed.

[0050] In this connection, however, it may also alternatively be provided that an opposite pre-tension means that, at the swivel joint between the second steering rod 14b, 20b and the respective track rod 14c, 20c in each case, the first and second steering mechanism 14, 20 are pressed together elastically by the tensioning mechanism 26 by the amount for compensating or eliminating the steering play of the steering system 10.

[0051] In this case, the spacing between the two track rods 14c, 20c reduces in size, amongst other things, at the swivel joint of the two second steering rods 14b, 20b in such a way that the steering play is removed.

[0052] The tensioning mechanism 26 may furthermore have a longitudinal adjustment mechanism 26a.

[0053] The longitudinal adjustment mechanism 26a may be formed, for example, by two mutually axially displaceable linear guides, which are fastened to each other in the desired position (e.g. by one or more screw connections).

[0054] Additionally or alternatively, the tensioning mechanism 26 may comprise a telescopic mechanism.

[0055] The tensioning mechanism 26 may furthermore comprise an elastic spring element (not shown in FIG. 1).

[0056] The elastic spring element may be designed as an axial spring element.

[0057] The axial spring element here may be designed as an axial pressure spring element or as an axial tension spring element.

[0058] In this connection, as the axial pressure spring element, it is contemplated to use, in particular, helical pressure springs, diaphragm springs, disk springs, volute springs, annular springs, gas pressure springs or oil pressure springs.

[0059] In this regard, as the axial tension spring element, it is furthermore contemplated to use, in particular, helical tension springs and all further above-mentioned spring elements which are also suitable for use as axial tension springs.

[0060] The elastic spring element may furthermore be additionally or alternatively designed as a radial spring element.

[0061] In particular, leaf spring elements or rod spring elements are contemplated here.

[0062] According to FIG. 1, the second steering gear 18 is designed to be smaller than the first steering gear 12 in at least one dimension.

[0063] The second steering gear 18 is, in particular, designed to be at least ca. 10% smaller than the first steering gear 12 in one dimension.

[0064] The second steering gear 18 is, however, preferably designed to be at least 20% smaller than the first steering gear 12 in at least one dimension.

[0065] However, the second steering gear 18 is particularly preferably designed to be at least 25% smaller than the first steering gear 12 in at least one dimension.

[0066] According to FIG. 1, this dimension is, for example, the length of the two steering gears 12, 18.

[0067] However, it is additionally or alternatively contemplated that this dimension is also the width or the height of the two steering gears 12, 18.

[0068] The second steering gear 18 may furthermore also be designed to be smaller than the first steering gear 12 in two dimensions or in three dimensions.

[0069] The first steering gear 12 is furthermore coupled to a first electric motor 28.

[0070] The first electric motor 28 is flange-mounted on the first steering gear 12 and drives an internal spindle or ball screw, which then transmits its driving moment or steering moment to the first output shaft.

[0071] The first output shaft is in turn coupled to the first steering mechanism 14, so that the rotational movements of the output shaft are converted into steering movements of the first vehicle wheel 16.

[0072] The first steering gear 12 furthermore has a mechanical through-drive 30, via which the first steering gear 12 can be coupled to a steering column 32 and to a vehicle steering wheel 34.

[0073] The mechanical through-drive 30, like the first electric motor 28, is also connected to the spindle or ball screw in a torsion-resistant manner and drives this as a result of the manual steering movements of the vehicle steering wheel 34, generated by a vehicle driver, via the steering column 32.

[0074] According to FIG. 1, the second steering gear 18 is furthermore coupled to a second electric motor 36.

[0075] The second electric motor 36 is flange-mounted on the second steering gear 18 and drives a further internal spindle or ball screw, which then transmits the driving moment or steering moment to the second output shaft.

[0076] The second output shaft is in turn coupled to the second steering mechanism 20, so that the rotational movements of the output shaft are converted into steering movements of the second vehicle wheel 22.

[0077] As can furthermore be seen in FIG. 1, the second steering gear 18 can be driven exclusively by the second electric motor.

[0078] The second steering gear 18 is therefore not mechanically coupled to the steering column 32 or the vehicle steering wheel 34, but is driven only by the second electric motor 36.

[0079] The function of the steering system 10 can now be described as follows.

[0080] In normal operation, i.e. when all components of the steering system are functioning properly, a vehicle driver controls the steering system 10 via the vehicle steering wheel 34.

[0081] As soon as the vehicle driver controls the vehicle steering wheel 34 via a rotation, i.e. there is a relative change in the current angle of rotation, this rotation is, on the one hand, transmitted to the first steering gear 12 mechanically via the steering column 32.

[0082] The first steering gear 12 in turn transmits this rotation of the steering column 32 mechanically to the first steering mechanism 14, which in turn pivots or turns the first vehicle wheel 16 in a defined manner in response to the rotation at the vehicle steering wheel 34.

[0083] On the other hand, an angle-of-rotation sensor at the same time continuously detects the angle of rotation and the direction of rotation of the steering column 32 and/or the vehicle steering wheel 34 and transmits these values to a control and/or regulating device (not shown in FIG. 1) of the steering system 10 or of the utility vehicle.

[0084] Furthermore, at the same time, a torque sensor continuously detects the steering moment of the steering column 32 and/or the vehicle steering wheel 34 and likewise transmits these values to the control and/or regulating device.

[0085] On the basis of these values for the angle of rotation, direction of rotation and steering moment of the steering column 32 and/or vehicle steering wheel 34, the first and second electric motor 28, 36 are activated simultaneously and independently of each other by the control and/or regulating device with a minimum time lag from the manual mechanical steering movement (owing to the inertia of the system).

[0086] The two electric motors 28, 36 may thus activate the two steering gears 12, 18 independently of each other and simultaneously or synchronously with the manual mechanical activation via the vehicle steering wheel 34, thereby resulting in the steering assistance.

[0087] Play between the first and second steering gear 12, 18 is compensated as a result of the tensioning mechanism 26, which pre-tensions the first and second steering gear 12, 18 via the first and second steering mechanism 14, 20.

[0088] If the first and/or second electric motor 28, 36 fail(s), the tensioning mechanism 26 additionally serves as a driver to transmit the steering movements of the first steering mechanism 14 to the second steering mechanism 20 and vice versa.

[0089] However, the activation can still be ensured if only one electric motor 28, 36 is intact, since both electric motors 28, 36 may be activated independently of each other.

LIST OF REFERENCE SIGNS

[0090] 10 Steering system [0091] 12 First steering gear [0092] 14 First steering mechanism [0093] 14a First steering rod [0094] 14b Second steering rod [0095] 14c Track rod [0096] 14d Wheel carrier [0097] 16 First vehicle wheel [0098] 18 Second steering gear [0099] 20 Second steering mechanism [0100] 20a First steering rod [0101] 20b Second steering rod [0102] 20c Track rod [0103] 20d Wheel carrier [0104] 22 Second vehicle wheel [0105] 24 Front axle [0106] 26 Tensioning mechanism [0107] 26a Longitudinal adjustment mechanism [0108] 28 First electric motor [0109] 30 Mechanical through-drive [0110] 32 Steering column [0111] 34 Vehicle steering wheel [0112] 36 Second electric motor