Steering Gear for a Vehicle, More Particularly a Utility Vehicle

Abstract

Please substitute the new Abstract submitted herewith for the original Abstract: A recirculating ball steering gear for a steering system of a vehicle, in particular a utility vehicle, includes at least one housing, at least one steering spindle, at least one steering spindle nut which is guided in an axially displaceable manner inside the housing and which in the assembled state is connected to the steering spindle via a plurality of balls, and at least one bearing device, by which the steering spindle is supported in the housing. The bearing device, the steering spindle and the housing form an adjusted bearing arrangement.

Claims

1-12. (canceled)

13. A recirculating ball steering gear for a steering system of a vehicle, comprising: at least one housing; at least one steering spindle; at least one steering spindle nut which is guided in an axially displaceable manner inside the housing and which, in an assembled state, is connected to the steering spindle via a plurality of balls; and at least one bearing device, by which the steering spindle is supported in the housing, wherein the bearing device, the steering spindle, and the housing form an adjusted bearing arrangement.

14. The recirculating ball steering gear as claimed in claim 13, wherein the bearing device has at least one pretensioning device, by which the steering spindle is pretensionable in an axially and/or radially adjustable manner.

15. The recirculating ball steering gear as claimed in claim 13, wherein the bearing device has at least a first bearing unit and at least a second bearing unit.

16. The recirculating ball steering gear as claimed in claim 15, wherein in the assembled state, the first bearing unit is arranged in a region of a first end of the steering spindle and the second bearing unit is arranged in a region of a second end of the steering spindle.

17. The recirculating ball steering gear as claimed in claim 16, wherein the pretensioning device has at least a first pretensioning element which is arranged in the assembled state in the region of the first end of the steering spindle or in the region of the second end of the steering spindle.

18. The recirculating ball steering gear as claimed in claim 17, wherein the pretensioning device has at least a second pretensioning element which is arranged in the assembled state in the region of the second end of the steering spindle, and the first pretensioning element is arranged in the region of the first end of the steering spindle.

19. The recirculating ball steering gear as claimed in claim 15, wherein the first bearing unit has at least a first tapered roller bearing and the second bearing unit has at least a second tapered roller bearing.

20. The recirculating ball steering gear as claimed in claim 19, wherein the first tapered roller bearing and the second tapered roller bearing form, in the assembled state, an O-shaped arrangement.

21. The recirculating ball steering gear as claimed in claim 19, wherein in the assembled state, the first pretensioning element is screwed on the steering spindle in the region of the first end of the steering spindle and is adjusted against at least one internal ring of the first tapered roller bearing.

22. The recirculating ball steering gear as claimed in claim 21, wherein in the assembled state, the second pretensioning element is screwed on the steering spindle in the region of the second end of the steering spindle and is adjusted against at least one internal ring of the second tapered roller bearing.

23. The recirculating ball steering gear as claimed in claim 18, wherein in the assembled and adjusted state of the first and second pretensioning elements, pretensioning of the steering spindle is at least in the form of a tensile pretensioning.

24. The recirculating ball steering gear as claimed in claim 18, wherein the first pretensioning element is in the form of a slotted nut, and the second pretensioning element is in the form of a slotted nut.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0028] FIG. 1 is a schematic cross section of an embodiment of a steering gear according to the invention.

DETAILED DESCRIPTION OF THE DRAWING

[0029] The steering gear 10 is in the form of a recirculating ball steering gear 10 for a steering system of a utility vehicle (not shown in FIG. 1).

[0030] The steering gear 10 has a housing 12, a steering spindle 14 and a steering spindle nut 16 which is guided inside the housing in an axially displaceable manner.

[0031] In this case, the steering spindle nut 16 is guided in a round guide hole 12a of the housing 12 in an axially displaceable manner.

[0032] The guide hole 12a can particularly have a circular cross section and the guide surface of the steering spindle nut 16 can be in contact with the guide hole 12a completely circumferentially or partially circumferentially.

[0033] The steering spindle nut 16 is further connected to the steering spindle 14 in the assembled state via a plurality of balls or a recirculating ball system 14a.

[0034] In this case, the recirculating ball system 14a is intended to be understood so that it has a plurality of helical recirculating systems for balls 14a in an axial direction, as can be seen in FIG. 1.

[0035] The balls 14a are consequently guided in an axially extending helical or screw-like spindle groove 14b of the steering spindle, wherein the spindle groove 14b has a semicircular cross section.

[0036] Accordingly, the balls or the recirculating ball system 14a cooperate with an additional, corresponding, axially extending helical or screw-like slotted nut 16a/steering spindle nut 16, wherein the slotted nut 16a also has a semicircular cross section.

[0037] According to FIG. 1, a rotational movement of the steering spindle 14 is transmitted via the plurality of balls or the recirculating ball system 14a to the steering spindle nut 16, which results in the axial displacement movement of the steering spindle nut 16 inside the housing 14.

[0038] On a partial region of the covering face thereof, the steering spindle nut 16 further has a partial tooth arrangement 16b which in the assembled state is engaged with a segmented toothed wheel of a segmented shaft.

[0039] The steering gear 10 further comprises according to FIG. 1 a bearing device 18, by which the steering spindle 14 is supported in the housing 12.

[0040] The bearing device 18, the steering spindle 14 and the housing 12 form an adjusted bearing arrangement in this case.

[0041] The bearing device 18 further has a pretensioning device 20, by which the steering spindle 14 can be pretensioned in an axially adjustable manner.

[0042] Additionally or alternatively, it is contemplated that the steering spindle 14 can accordingly be pretensioned in a radial and adjustable manner by the pretensioning device 20.

[0043] The bearing device 18 further has a first bearing unit 18a and a second bearing unit 18b.

[0044] The first bearing unit 18a is arranged in the assembled state in the region of a first end 14c of the steering spindle 14.

[0045] Accordingly, the second bearing unit 18b is arranged in the region of a second end 14d of the steering spindle 14.

[0046] To this end, the steering spindle 14 has at the respective region or portion of the first and second end 14c, 14d thereof, a bearing seat for receiving the first and second bearing unit 18a, 18b, respectively.

[0047] The first end of the steering spindle 14 is further connected integrally to a steering engagement member 14e which can be connected to a steering column (not shown in FIG. 1) and a steering wheel.

[0048] The above-described pretensioning device 20 further comprises a first pretensioning element 20a which in the assembled state is arranged in the region of the first end 14c of the steering spindle 14.

[0049] Accordingly, the pretensioning device 20 has a second pretensioning element 20b which is in turn arranged in the assembled state in the region of the second end 14d of the steering spindle 14.

[0050] Alternatively to the first and second pretensioning element 20a, 20b, the pretensioning device 20 may have only one pretensioning element 20a, 20b which is then arranged in the region of the first or second end 14c, 14d of the steering spindle 14.

[0051] The pretensioning of the steering spindle 14 is then carried out via a corresponding shoulder (not shown in FIG. 1) of the steering spindle 14 which is arranged in the first region or second region of the opposite end 14c, 14d of the steering spindle 14, at which end the single pretensioning element 20a, 20b is not arranged.

[0052] According to FIG. 1, the first bearing unit 18a has a first tapered roller bearing, whereas the second bearing unit 18b accordingly has a second tapered roller bearing.

[0053] As can be seen in FIG. 1, the first tapered roller bearing and the second tapered roller bearing form an O-like arrangement in the assembled state.

[0054] The two tapered roller bearings are in the form of a single-rowed tapered roller bearing, wherein it is also contemplated for them to be able to be in the form of multiple-rowed tapered roller bearings either in a state individually juxtaposed beside each other or integrally.

[0055] In particular, two-rowed or four-rowed tapered roller bearings are contemplated in this context.

[0056] In the case of multiple-rowed tapered roller bearings, they can each be configured in an X-like, O-like or tandem arrangement.

[0057] As can further be seen in FIG. 1, in the assembled state the first pretensioning element 20a is screwed on the steering spindle in the region of the first end 14c of the steering spindle 14 and is adjusted against an internal ring of the first tapered roller bearing.

[0058] Accordingly, in the assembled state the second pretensioning element 20b is further screwed on the steering spindle 14 in the region of the second end 14d of the steering spindle 14 and adjusted against an internal ring of the second tapered roller bearing.

[0059] The first bearing unit 18a and the second bearing unit 18b are consequently constructed or arranged symmetrically with respect to an axial center axis and have the same components.

[0060] The first and second pretensioning elements 20a, 20b are in the form of slotted nuts.

[0061] As a result of the adjustment of the two slotted nuts against the two internal rings of the respective tapered roller bearings, therefore, in the assembled and adjusted state of these two pretensioning elements the pretensioning of the steering spindle 14 is in the form of a tensile pretensioning.

[0062] The two slotted nuts are further each secured by a securing plate so as to prevent undesirable release, wherein the securing plates are not illustrated in FIG. 1.

[0063] Furthermore, in the assembled state an external ring of the first tapered roller bearing is adjusted in the region of the first end 14c of the steering spindle 14 against a first housing shoulder of the housing 12 or a first housing cover.

[0064] Consequently, an external ring of the second tapered roller bearing is adjusted in the region of the second end 14d of the steering spindle 14 against a second housing shoulder of the housing 12 or a second housing cover.

[0065] As can further be seen in FIG. 1, the steering gear 10 is illustrated without any additional auxiliary drives, such as a hydraulic pump, a hydraulic piston or an electric motor for generating an additional auxiliary steering torque.

[0066] Particularly in this context, there may be provision for an electric motor or a servo motor to be flange-mounted on the steering gear 10 from FIG. 1 and for it to be connected to the steering spindle 14 in a rotationally secure manner directly via a clutch or indirectly via a step-down gear mechanism.

[0067] The electric motor could be flange-mounted on the housing 12 in such a manner that it is connected to the steering spindle 14 in the region of the first or second end 14c, 14d of the steering spindle 14.

[0068] Additionally or alternatively, there may be provision for the intermediate spaces of the round guide hole 12a of the housing 12 which are formed between the steering spindle nut 16 and the two bearing units 18a, 18b to be able to be acted on via a hydraulic pump with oil pressure.

[0069] Additionally or alternatively, a hydraulic auxiliary steering power support unit could accordingly be implemented.

[0070] However, the necessary housing lines, the hydraulic pump and the corresponding control valve for controlling the two intermediate spaces of the round guide hole 12a of the housing 12 are not illustrated in FIG. 1.

[0071] The same applies to the adaptation of the steering spindle nut 16 for sealing these two intermediate spaces relative to each other and with respect to the bearing units 18a, 18b so that the steering spindle nut 16 would then function additionally as a hydraulic piston.

[0072] The function of the steering gear 10 according to the invention can now be described as follows.

[0073] In the region of the first end 14c of the steering spindle 14 which can be connected to a steering wheel via a steering column, the rotary spindle is rotated via the steering engagement member 14e depending on the vehicle driver’s steering wishes.

[0074] As a result of the connection of the steering spindle 14 to the steering spindle nut 16 via the recirculating ball system 14a, there is consequently produced an axial displacement movement or translational movement of the steering spindle nut 16 inside the housing 12.

[0075] As can further be seen in FIG. 1, the steering spindle nut 16 is itself in engagement with a segmented toothed wheel of a segmented shaft via a partial tooth arrangement at the covering face thereof.

[0076] In this regard, the axial displacement movement or translational movement of the steering spindle nut 16 is transmitted to the segmented toothed wheel, which results in a rotation of the segmented shaft.

[0077] The segmented shaft is again connected in a rotationally secure manner to a steering lever (not shown in FIG. 1) which is pivoted via the rotation of the segmented shaft and which transmits this pivoting movement to a steering mechanism which then pivots the wheels of a vehicle axle in accordance with the driver’s wishes.

[0078] As a result of the tooth engagement between the steering spindle nut 16 and segmented toothed wheel, the steering spindle nut 16 is subjected for each translational movement to a radial force which it transmits to the steering spindle 14 via the recirculating ball system 14a.

[0079] Since the steering spindle 14 according to the present invention is pretensioned axially by a tensile tension, however, the steering spindle 14 is subjected to a smaller radial force or radial deformation of the steering spindle nut 16 so that the wear can be reduced according to the invention at the steering spindle 14, recirculating ball system 14a and steering spindle nut 16.

TABLE-US-00001 LIST OF REFERENCE NUMERALS 10 Recirculating ball steering gear 12 Housing 12a Guide hole 14 Steering spindle 14a Balls or recirculating ball system 14b Spindle groove 14c Region of first end of steering spindle 14d Region of second end of steering spindle 14e Steering engagement member 16 Steering spindle nut 16a Slotted nut 16b Partial tooth arrangement 18 Bearing device 18a First bearing unit 18b Second bearing unit 20 Pretensioning device 20a First pretensioning device 20b Second pretensioning device