STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column for a motor vehicle comprises an actuating unit. A steering spindle is mounted rotatably about a longitudinal axis extending in the longitudinal direction. A supporting unit is connectable to a motor vehicle body and in which the actuating unit is held so as to be displaceable in the longitudinal direction. An energy absorption device, which is incorporated between the supporting unit and the actuating unit, has an elongate energy absorption element fastened to the actuating unit or to the supporting unit via a fastening. A deformation member, which interacts with the energy absorption element, is attached to the supporting unit or to the actuating unit. In the event of a crash with a relative displacement of actuating unit and supporting unit, the deformation member brings about an energy-absorbing plastic deformation of the energy absorption element.

Claims

1-12. (canceled)

13. A steering column for a motor vehicle, the steering column comprising: an actuating unit, in which a steering spindle is mounted rotatably about a longitudinal axis (L) extending in the longitudinal direction; a supporting unit, which is connectable to a motor vehicle body and in which the actuating unit is held so as to be displaceable in the longitudinal direction; and an energy absorption device, which is incorporated between the supporting unit and the actuating unit and has an elongate energy absorption element, fastened to the actuating unit or to the supporting unit via a fastening, and has a deformation member, which interacts with said energy absorption element, is attached to the supporting unit or to the actuating unit and, in the event of a crash with a relative displacement of actuating unit and supporting unit, brings about an energy-absorbing plastic deformation of the energy absorption element; wherein the fastening has at least one fastening device that is offset-compensating in the longitudinal direction.

14. The steering column as claimed in claim 13 wherein the fastening is arranged in each end region of the energy absorption element.

15. The steering column as claimed in claim 14 wherein the fastening has a fixing connection secured in the longitudinal direction.

16. The steering column as claimed claim 15 wherein the offset-compensating fastening device has an elongated hole which extends in the longitudinal direction and through which a connecting element extends.

17. The steering column as claimed in claim 16 wherein the elongated hole is formed in the energy absorption element, and the connecting element is fixed to the actuating unit.

18. The steering column as claimed in claim 17 wherein the elongated hole is closed in the longitudinal direction.

19. The steering column as claimed in claim 18 wherein the elongated hole is open at one end.

20. The steering column as claimed in claim 19 wherein the energy absorption element has a deformation strip around which the deformation member engages.

21. The steering column as claimed in claim 20 wherein the supporting unit has a casing unit which is adjustable in the vertical direction (H) and in which the actuating unit is accommodated.

22. The steering column as claimed in claim 21 wherein the actuating unit has a casing tube which is arranged telescopically in a casing unit.

23. The steering column as claimed in claim 22 wherein the supporting unit has a clamping device which can be brought into a fixing position or a release position, wherein the actuating unit is secured relative to the supporting unit in the fixing position, and is adjustable relative to the supporting unit in the release position.

24. The steering column as claimed in claim 23 wherein a motorized adjusting drive is arranged between the supporting unit and the actuating unit.

Description

DESCRIPTION OF THE DRAWINGS

[0032] Advantageous embodiments of the invention will be explained in more detail below with reference to the drawings. Specifically:

[0033] FIG. 1 shows a steering column according to the invention in a schematic perspective illustration,

[0034] FIG. 2 shows the steering column according to FIG. 1 in a further perspective illustration,

[0035] FIG. 3 shows an energy absorption device of a steering column according to FIG. 1 in a cropped illustration,

[0036] FIG. 4 shows a view of a detail of the energy absorption element from FIG. 3,

[0037] FIG. 5 shows the energy absorption device according to FIG. 3 in a further perspective view,

[0038] FIG. 6 shows a partially schematic side view of a steering column according to FIG. 1 in a normal operating state before a crash,

[0039] FIG. 7 shows a partially schematic side view of a steering column analogously to FIG. 6 after a crash,

[0040] FIG. 8 shows a second embodiment of a steering column according to the invention in a schematic perspective illustration,

[0041] FIG. 9 shows a view of a detail as in FIG. 3 of an energy absorption element in a second embodiment.

EMBODIMENTS OF THE INVENTION

[0042] In the various figures, identical parts are always provided with the same reference signs and are therefore usually each only named or mentioned once in each case.

[0043] FIGS. 1 and 2 illustrate a steering column 1 according to the invention schematically in a perspective view obliquely from the rear (based on the direction of travel of a motor vehicle which is not shown).

[0044] The steering column 1 can be fastened to the body of a motor vehicle, not illustrated, by means of a supporting unit 2, also called a bracket. For the connection to the vehicle body, the supporting unit 2 comprises fastening means 21 which are designed here as fastening openings. In the embodiment variant illustrated here, the supporting unit 2 is produced as a cast part from a light metal alloy. Alternatively, a supporting unit 2 which is in the form of a sheet metal bent component is also conceivable and possible.

[0045] An actuating unit 3 comprises a steering spindle 30 which is mounted in an inner casing tube 31, also called inner casing 31, so as to be rotatable about its longitudinal axis L extending in the longitudinal direction. A fastening portion 32 for fastening a steering wheel, not illustrated, for the manual input of steering commands is formed at the rear of the steering spindle 30. The inner casing tube 31 is accommodated and held in an outer casing tube 33, also called for short outer casing, outer casing unit or casing unit, so as to be displaceable telescopically in the longitudinal direction.

[0046] To realize a vertical adjustment, the casing unit 33 is mounted on the supporting unit 2 so as to be pivotable about a horizontal pivot axis 22 such that the steering spindle 30 can be moved up and down in a vertical direction H, as is indicated by the double arrow.

[0047] An adjusting drive 4 designed as a rotational spindle drive serves for the vertical adjustment and has a drive unit 41 with a drive housing 42 on which an electric motor 43 is flange-mounted as the drive motor. A transmission, which is not illustrated specifically here, coupled to the motor 43 is accommodated in the drive housing 42 and can be designed, for example, as a worm transmission. At the output of the transmission, a threaded spindle 44 can be driven so as to rotate about its spindle axis. Said threaded spindle 44 extends axially, i.e. in the direction of the spindle axis from the drive housing 42 which, for its part, is supported axially on the casing unit 33.

[0048] The threaded spindle 44 engages by means of its outer thread in a spindle nut 45 which is fixed with respect to rotation about the spindle axis G. The spindle nut 45 acts on an actuating lever 23 which is mounted between the casing unit 33 and the supporting unit 2 in horizontal pivot bearings spaced apart from one another. As a result, a rotating drive of the threaded spindle 44 leads to an axial linear displacement of the spindle nut 45 and thereby to an adjustment of the actuating lever 23, as a result of which the outer casing tube 33 together with the actuating unit 3 can be adjusted in the vertical direction H relative to the supporting unit 2.

[0049] A second adjusting drive 5, likewise constructed similarly in principle as a spindle drive, is provided for the longitudinal adjustment. Said adjusting drive comprises a drive unit 51, a drive housing 52, a motor 53, a threaded spindle 54 and a spindle nut 55. The drive housing 52 is supported axially on the outer casing 33, the threaded spindle 54 lies substantially parallel to the longitudinal axis L, and the spindle nut 55 acts on the casing tube 31 in the direction of the longitudinal axis L. By activation of the drive unit 51, the inner casing tube 31 can thereby be telescopically retracted or extended in the longitudinal direction relative to the outer casing 33, as indicated by a double arrow.

[0050] An energy absorption device 6 is shown in schematically cropped form in FIG. 3 in the perspective of FIG. 2, with the outer casing 33 being omitted for better clarity. FIG. 5 shows a view from the opposite side, with the inner casing tube 31 also being omitted. FIGS. 6 and 7 show side views of the arrangement of FIG. 3 before a crash (FIG. 6) and after a crash (FIG. 7).

[0051] The energy absorption device 6 comprises an energy absorption element which is in the form of a deformation strip 61. The latter has a strip-shaped deformation portion 62 which is elongated in the longitudinal direction, and has, in its rear end region, a fastening portion 63 configured according to the invention, and, in its other, front end region, a conventional fastening portion 64. Between the fastening portions 63, 64, the deformation portion 62 has the energy absorption portion.

[0052] The fastening portion 63, 64 are bent such that they lie against the outside of the inner casing tube 31, while the deformation portion 52 is at a distance from the outer surface of the inner casing tube 31.

[0053] The fastening portion 63 illustrated in detail in enlarged form in FIG. 4 has, according to the invention, an elongated hole 65 which is elongate in the longitudinal direction. A connecting element 7 which can be in the form of a rivet or bolt and which is movable in the longitudinal direction in the elongated hole 65 extends through the elongated hole 65. The connecting element 7 preferably has a head 71 which protrudes transversely over the elongated hole 65 and therefore holds the fastening portion 63 in a form-fitting manner from the outside of the inner casing tube 31.

[0054] The connecting element 7 which is displaceable longitudinally in the elongated hole 65 forms an offset-compensating fastening within the meaning of the invention, which makes it possible for the fastening portion 63 to be movable relative to the inner casing tube 31 in a manner guided in the longitudinal direction.

[0055] The elongated hole 65 and the connecting element 7 are preferably designed in such a manner that they are movable relative to each other with as little force as possible in the event of a crash in order thus to permit the offset-compensating displacement according to the invention.

[0056] The elongated hole 65 preferably has, at least in one portion, a clearance fit with respect to the connecting element 7. Tests have shown that clearance fits with a play of more than 10 .Math.m have virtually no interfering resistance forces during the offset compensation, and in particular stick-slip effects can thus be very substantially avoided.

[0057] A fastening opening 66 is formed in the other fastening portion 64 and the passage cross section of said fastening opening corresponds substantially without play to the connecting element 7 inserted through it, for example is circular like the connecting element, and therefore a fixing connection which is also secured in a form-fitting manner in the longitudinal direction is produced between the deformation strip 61 and the inner casing tube 31 of the actuating unit 3.

[0058] A deformation member in the form of a deformation slide 67 is attached to the spindle nut 55 and is fastened via the threaded spindle 54 and the drive housing 52 to the outer casing 33 and is supported in the longitudinal direction.

[0059] The deformation slide 67 has a U-shaped basic shape with two deformation limbs 68 which mutually delimit a passage which is longitudinally continuous. The deformation slide 67 engages around the deformation strip 61 from the outside in such a manner that the deformation portion 62 is guided through the passage. The distance between the deformation limbs 68, which indicates the width of the passage, is smaller than the width of the deformation portion 62 as measured transversely with respect to the longitudinal direction.

[0060] In the event of a crash, a body impacting against the steering wheel causes a large force F to act forward in the longitudinal direction against the actuating unit 3, as is indicated schematically in FIG. 6 in the side view of the actuating unit 3 before the crash. This crash force F causes the inner casing tube 31 together with the deformation strip 61 to be displaced forward relative to the outer casing 33 and the adjusting drive 5 attached thereto. The deformation portion 62 is pushed forward in the longitudinal direction through the passage of the deformation slide 67 which, in FIGS. 6 and 7, is concealed by the spindle nut 55 supported on the adjusting drive 5 and is shown by dashed lines. By means of the deformation limbs 68, the deformation portion 62 is plastically squeezed together continuously transversely over its length in the crash, as a result of which kinetic energy is converted into work of deformation and is thereby absorbed.

[0061] By means of the continuous squeezing together in the transverse direction, the deformation portion 62 is not only plastically deformed in the transverse direction, but also lengthened in the longitudinal direction by an amount X, i.e. extended or lengthened plastically in the longitudinal direction, as shown in the state after the crash in FIG. 7. The fixing connection of the front fastening portion 64 is fixed in the longitudinal direction. The lengthening causes the rear fastening portion 63 to move rearward by an offset with the amount X. The connecting element 7 can slide along in the elongated hole 65 in an offset-compensating manner such that the fastening portion 63 can move to the rear in the longitudinal direction relative to the actuating unit 3. As a result, the offset produced by the lengthening of the deformation strip 61 is compensated for, and bending stresses which could lead to a damaging sagging of the deformation portion 62 in the event of a crash do not occur.

[0062] FIG. 9 shows, in the same view as FIG. 4, a modification of the invention, with the elongated hole 65 being open toward the end of the fastening portion 63, i.e. having an opening 69. As a result, an easily mountable, fork-shaped arrangement is formed.

[0063] FIG. 8 shows, in a view similar to FIG. 1, a manually adjustable steering column 1 which does not have adjusting drives 5, 6, but otherwise the same reference signs are used.

[0064] The outer casing 33 is arranged in a vertically adjustable manner between two side cheeks 24 protruding downward in a fork-shaped manner. By means of a clamping device 8, which can be brought either into a fixing position or release position by manual actuation of a clamping lever 81, said side cheeks 24 can be braced in the fixing position with a force fit against the outer casing 33 such that the latter is fixed in the vertical direction between the side cheeks 24 and at the same time the inner casing 31 is clamped in the outer casing 33 and fixed in the longitudinal direction relative thereto. The bracing is released in the release position, and therefore manual adjustment in the longitudinal and vertical directions can take place.

[0065] As in the first embodiment adjustable by motor, the energy absorption device 6 is incorporated in terms of effect in the longitudinal direction between inner casing 31 and outer casing 33. The lengthening X occurring in the event of a crash can be compensated for, as described, by the offset-compensating configuration of the fastening of the rear fastening portion 63 of the deformation strip 61 such that the advantages according to the invention are realized.

TABLE-US-00001 List of reference signs 1 steering column 2 supporting unit 21 fastening means 22 pivot axis 23 actuating lever 24 side cheek 3 actuating unit 31 inner casing tube 32 fastening portion 33 outer casing tube (outer casing) 4, 5 adjusting drive 41,51 drive unit 42,52 drive housing 43,53 motor 44,54 threaded spindle 45,55 spindle nut 6 energy absorption device 61 deformation strip 62 deformation portion 63,64 fastening portion 65 elongated hole 66 fastening opening 67 deformation slide 68 deformation limb 69 opening 7 connecting element 71 head 8 clamping device 81 clamping lever L longitudinal axis H vertical direction F crash force X amount of the lengthening (offset)