STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column is disclosed for a motor vehicle, including an actuating unit, in which a steering spindle is rotatably mounted about a longitudinal axis. The actuating unit includes a casing unit which has at least three casing tubes which are arranged so as to be axially telescopable relative to one another. One of the casing tubes forms an outer casing tube in which at least one intermediate casing tube, in which an inner casing tube is accommodated, is accommodated. Rolling bodies are arranged between the casing tubes such that they are able to roll in the axial direction. First rolling bodies are arranged between the outer casing tube and the intermediate casing tube, and second rolling bodies are arranged between the intermediate casing tube and the inner casing tube, the first rolling bodies being arranged offset in the circumferential direction relative to the second rolling bodies.

Claims

1.-11. (canceled)

12. A steering column for a motor vehicle, comprising: a steering spindle; an actuating unit, in which the steering spindle is mounted so as to be able to rotate about a longitudinal axis, the actuating unit comprising: a casing unit which comprises casing tubes arranged to axially telescope relative to one another, the casing tubes comprising an outer casing tube in which an intermediate casing tube of the three casing tubes is disposed, and an inner casing tube disposed within the intermediate casing tube, and rolling bodies disposed between the casing tubes, such that the rolling bodies roll in the axial direction, wherein first rolling bodies of the rolling bodies are arranged between the outer casing tube and the intermediate casing tube, and second rolling bodies of the rolling bodies are arranged between the intermediate casing tube and the inner casing tube, the first rolling bodies being arranged offset in the circumferential direction relative to the second rolling bodies.

13. The steering column of claim 12 wherein the first rolling bodies are arranged in one or more axially parallel first rows and the second rolling bodies are arranged in one or more axially parallel second rows.

14. The steering column of claim 12 wherein the first rolling bodies are accommodated in a first rolling body cage and the second rolling bodies are accommodated in a second rolling body cage.

15. The steering column of claim 14 wherein the first and second rolling cage is at least partially of slotted configuration in the direction of the longitudinal axis.

16. The steering column of claim 12 wherein the casing tubes comprise raceways for the rolling bodies, said raceways extending in the direction of the longitudinal axis.

17. The steering column of claim 16 wherein at least one of the raceways and/or the rolling bodies are/is of cambered configuration.

18. The steering column of claim 12 wherein the casing tubes each have a polygonal cross section.

19. The steering column of claim 12 comprising two intermediate casing tubes which axially telescope relative to one another and third rolling bodies disposed between the two intermediate casing tubes, the third rolling bodies offset relative to the first rolling bodies and/or second rolling bodies.

20. The steering column of claim 12 further comprising a motorized adjustment drive connected to the inner casing tube and the outer casing tube, the drive configured to axially retract and extend the inner casing tube relative to the outer casing tube.

21. The steering column of claim 12 wherein the steering spindle is coupled to a feedback actuator.

22. A steering column for a motor vehicle, comprising: a steering spindle; an actuating unit, in which the steering spindle is mounted so as to be able to rotate about a longitudinal axis, the actuating unit comprising: a casing unit which comprises casing tubes arranged so as to be axially telescopable relative to one another, and rolling bodies arranged between the casing tubes so as to roll in the direction of the longitudinal axis, wherein the casing tubes comprise raceways for the rolling bodies, said raceways extending in the direction of the longitudinal axis, herein at least one of the raceways and/or the rolling bodies are/is of cambered configuration.

Description

DESCRIPTION OF THE DRAWINGS

[0028] Below, advantageous embodiments of the invention are described in more detail on the basis of the drawings. In detail:

[0029] FIG. 1 shows a schematic perspective view of a steering column according to the invention,

[0030] FIG. 2 shows a schematic partial interior view of the steering column according to FIG. 1,

[0031] FIG. 3 shows an enlarged detail view of FIG. 2,

[0032] FIG. 4 shows a longitudinal section (along the longitudinal axis) through the steering column according to FIG. 1,

[0033] FIG. 5 shows an enlarged detail view of FIG. 3,

[0034] FIG. 6 shows a cross section through the steering column according to FIGS. 1 to 5,

[0035] FIG. 7 shows a schematic perspective view of rolling body cages of the steering column according to FIG. 1,

[0036] FIG. 8 shows an enlarged detail view of FIG. 6 in a first embodiment,

[0037] FIG. 9 shows an enlarged detail view of FIG. 6 in a second embodiment,

[0038] FIG. 10 shows an enlarged detail view of FIG. 6 in a third embodiment, and

[0039] FIG. 11 shows an enlarged detail view of FIG. 6 in a fourth embodiment.

EMBODIMENTS OF THE INVENTION

[0040] In the various figures, the same parts are always provided with the same reference signs, and will therefore generally also be referred to or mentioned only once in each case.

[0041] FIG. 1 shows a view, obliquely from the rear with respect to the direction of travel, of a steering column 1 according to the invention which comprises an actuating unit 2. The actuating unit 2 comprises a casing unit 3 which comprises an outer casing tube 31, an intermediate casing tube 32 and an inner casing tube 33. The casing tubes 31, 32 and 33 are arranged coaxially in one another such that they can be displaced in a telescoping manner in the direction of a longitudinal axis L, as indicated with a double-headed arrow.

[0042] A steering spindle 4, which, at the rear end thereof, comprises a connection portion 41 for the attachment of a steering wheel (not illustrated), is mounted in the casing unit 3 such that it is able to rotate about the longitudinal axis L.

[0043] The actuating unit 3 is held in a carrying unit 5 which comprises fastening means 51 for attachment to a vehicle body (not illustrated).

[0044] An adjustment drive 6 comprises a spindle drive having a spindle nut 61 and a threaded spindle 62 screwed therein, which can be driven in a rotating manner relative to one another by an electric motor 63. The threaded spindle 62 extends parallel to the longitudinal axis L and is connected to the inner casing tube 33, and the spindle nut 61 is supported in the longitudinal direction, which corresponds to the axial direction of the longitudinal axis L, on the outer casing tube 31. As a result of a relative rotation by means of the motor 63, the threaded spindle 62 and the spindle nut 61 are moved together or apart from one another, depending on the direction of rotation, as a result of which the inner casing tube 33 is retracted or extended, in the axial direction, into or out of the outer casing tube 31, as indicated with the double-headed arrow. As a result, longitudinal adjustment is realized, by way of which a steering wheel which is attached to the connection portion 41 can be brought, toward the front, into a stowage position in which the inner casing tube 33 and the intermediate casing tube 32 are retracted, that is to say sunk toward the front, in the outer casing tube 31.

[0045] As an alternative, the spindle nut 61 can be supported on the inner casing tube 33, and the threaded spindle 62 can be supported on the outer casing tube 31.

[0046] In FIG. 2, the outer casing tube 31 and the intermediate casing tube 32 have been cut open and thus partially omitted, such that first rollers 7, which form first rolling bodies and are accommodated in a first roller cage 71 such that they are able to rotate about their roller axis, and second rollers 8, which form second rolling bodies and are accommodated in a second roller cage 81 such that they are able to rotate loosely about their roller axis, are visible. The arrangement of the rollers 7 and 8, and also of the roller cages 71 and 81, is explained in detail in FIGS. 3 to 11 below.

[0047] The casing tubes 31, 32 and 33 and the roller cages 71 and 81 have an octagonal profile cross section, as can be seen in FIG. 6 which shows a cross section through the casing unit 3 in the retracted state, in which the inner casing tube 33 and the intermediate casing tube 32 are retracted into the outer casing tube 31. It can be discerned therefrom that the first rollers 7 are arranged between the outer casing tube 31 and the intermediate casing tube 32, and the second rollers 8 are arranged between the intermediate casing tube 32 and the inner casing tube 33. In this case, the rollers 7 and 8 are able to roll, about their roller axes which lie transversely with respect to the longitudinal axis, in the axial direction of the longitudinal axis L on raceways 91, 92, 93, 94 which are configured on the casing tubes 31, 32 and 33.

[0048] The roller cages 71 and 81 are of tube portion sleeve-shaped configuration and, like the casing tubes 31, 32 and 33, have an octagonal cross section, as can be seen in the separated view of FIG. 7. The roller cage 71 is arranged coaxially between the outer casing tube 31 and the intermediate casing tube 32, and the roller cage 81 is arranged coaxially between the intermediate casing tube 32 and the inner casing tube 33.

[0049] The first rollers 7 are arranged in the roller cage 71 in each case in rows of six on those sides 71a of the octagonal profile between which sides 71b without rollers are in each case located in the circumferential direction. The second rollers 8 are arranged in the roller cage 81 in each case in rows of six on those sides 81b of the octagonal profile between which sides 81a without rollers are in each case located in the circumferential direction. The roller cages 71 and 81 are oriented such that, in cross section, in each case the sides 71a and 81a, and the sides 71b and 81b, lie radially above one another in adjacently parallel fashion. As a result, the rollers 7 and 8 are arranged offset relative to one another in the circumferential direction, and specifically offset in each case by an eighth of the circumference in the octagonal cross section which is illustrated. The linear guides, which are each formed by a row of rollers 7 and 8, respectively, are arranged at a spacing with respect to the longitudinal axis L over the circumference, here at an angular offset a of 360/8=45, as can be seen in FIG. 6.

[0050] The roller cages 71 and 81 each comprise a slot 72 and 82, respectively, which is continuous in the longitudinal direction, as can be seen in FIGS. 3 and 7. The slots 72 and 82, just like the linear guides, are offset relative to one another in the circumferential direction, by an eighth of the circumference in the example which is shown. However, it is also conceivable and possible to configure the roller cages 71 and 81 without a slot and thus with a closed cross-sectional profile.

[0051] The arrangement of the linear guides which are formed by the rows of the rollers 7, together with the raceways 91 and 92, and the rollers 8, together with the raceways 93 and 94, said arrangement being offset in the circumferential direction according to the invention, can likewise be seen in the perspective view of FIG. 3.

[0052] From the longitudinal section of FIG. 4 and the enlarged view thereof of FIG. 5, which show a sectional view A-A according to FIG. 6, it emerges that, in that circumferential region in which the rollers 8 are arranged between the intermediate casing tube 32 and the inner casing tube 33, there are no rollers between the outer casing tube 31 and the intermediate casing tube 32, but rather merely the wall of that side 71b of the roller cage 7 which bears no rollers. As a result, a space-saving arrangement is realized, which also makes improved vibration behavior and a relatively high stiffness of the casing unit 3 possible.

[0053] FIGS. 8, 9, 10 and 11 each illustrate an enlarged cross section through one of the linear guides in different embodiments of the rollers 7 and 8, respectively, between the raceways 91 and 92, and 93 and 94, respectively, with only a first roller 7 and first raceways 91 and 92 being indicated merely for the sake of clarity, which can, however, equally be applied to an embodiment and arrangement of second rollers 8 between second raceways 93 and 94.

[0054] In the example of FIG. 8, the raceways 91 and 92 are of planar configuration and extend in an axially parallel tangential plane, and the roller 7 is of cambered configuration. Said cambered roller 7 has a barrel-shaped convexity and has, in the middle region thereof, a diameter D which is larger than the diameter d at the end regions. As a result, the roller 7 contacts the middle of the raceways 91 and 92 in a short, linear, virtually punctiform contact area.

[0055] In the example of FIG. 9, the roller 7 is of cylindrical configuration with a same continuous diameter D, and the raceways 91 and 92 are both of cambered configuration. The cambered raceway 91 is curved convexly toward the inside in an arcuate manner, and the raceway 92 is curved convexly toward the outside in an arcuate manner, such that the raceways 91 and 92 have a spacing D in the middle circumferential region and only contact the roller 7 there, and, on the outside, in the end regions of the roller 7, have a larger spacing E, such that the roller 7 is not contacted there. As a result, a relatively small contact area is produced as compared with the embodiment of FIG. 7.

[0056] In the embodiment which is shown in FIG. 10, the roller 7, as in FIG. 9, is of cylindrical configuration with the same continuous diameter D. However, in contrast to FIG. 9, the outer raceway 91 is of planar configuration, and only the inner raceway 92 is cambered. In the middle region, the raceways have the spacing D; on the outside, a larger spacing F relative thereto. As a result, the roller 7 lies against the raceway 91 with a linear contact surface, and lies against the inner raceway 92 in a short, linear, virtually punctiform support.

[0057] The embodiment according to FIG. 11 is similar to the embodiment according to FIG. 10, with the difference that, in this case, the inner raceway 92 is planar, and the outer raceway 91 is cambered, as in the embodiment according to FIG. 9.

[0058] In addition, it is possible for the cambered embodiment of the roller 7, as shown in FIG. 8, to be combined with cambered raceways 91 and/or 92.

[0059] Correspondingly, the roller 8 can be cambered or cylindrical, and/or the raceways 93 and/or 94 can be cambered or cylindrical.

[0060] A stop 34 can be attached to the outer casing tube 31, said stop protruding, at the open end, inwardly into the interspace between the outer casing tube 31 and the intermediate casing tube 32. When being moved out, the roller cage 71 strikes against the stop 34 in the axial direction and is secured against separation from the outer casing tube 31. A stop 35 which protrudes outwardly into the interspace between the outer casing tube 31 and the intermediate casing tube 32 can be attached at the inner end of the intermediate casing tube 32, said stop preventing the roller cage 71 from detaching from the intermediate casing tube 32 in the axial direction, and likewise securing the intermediate casing tube 32 against being pulled out of the outer casing tube 31.

[0061] The steering spindle 4 is likewise of telescopable configuration, having an inner shaft 43 which engages in a form-fitting manner into an outer shaft 42 and which can be telescoped in the longitudinal direction, with rolling bodies 44 being able to be inserted therebetween in order to form a smooth-running, rolling-bearing-mounted linear bearing arrangement. As an alternative, a sliding guide can be provided between the inner shaft 43 and the outer shaft 42.

LIST OF REFERENCE SIGNS

[0062] 1 Steering column [0063] 2 Actuating unit [0064] 3 Casing unit [0065] 31 Outer casing tube [0066] 32 Intermediate casing tube [0067] 33 Inner casing tube [0068] 34, 35 Stop [0069] 4 Steering spindle [0070] 41 Connection portion [0071] 42 Outer shaft [0072] 43 Inner shaft [0073] 44 Rolling body [0074] 5 Carrying unit [0075] 51 Fastening means [0076] 6 Adjustment drive [0077] 61 Spindle nut [0078] 62 Threaded spindle [0079] 63 Motor [0080] 7,8 Rollers [0081] 71, 81 Roller cages [0082] 71a Side (with rollers) [0083] 71b Side (without rollers) [0084] 81a Side (without rollers) [0085] 81b Side (with rollers) [0086] 72, 82 Slot [0087] 91, 92, 93, 94 Raceway [0088] L Longitudinal axis [0089] D, d Diameter (roller) [0090] E, F Spacing