STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column for a motor vehicle may include a casing unit in which a steering spindle is mounted so as to be rotatable about a longitudinal axis extending in a length direction. The casing unit may have at least two casings that are adjustably guided relative to one another through a range of adjustment travel in the length direction. Part of the adjustment travel may correspond to a transitional portion, and part of the adjustment travel may correspond to a functional portion. The casings may be guided with a greater play in the transitional portion than in the functional portion. One casing may have a guide track and another casing may have a guide element that engages in the guide track and is guided in the length direction and has a guide play in the guide track that is greater in the transitional portion than in the functional portion.

Claims

1.-15. (canceled)

16. A steering column for a motor vehicle, comprising: a casing unit in which a steering spindle is mounted so as to be rotatable about a longitudinal axis that extends in a length direction, the casing unit having casings that are adjustably guided relative to one another through a range of adjustment travel in the length direction, wherein part of the range of adjustment travel corresponds to a transitional portion and part of the range of adjustment travel corresponds to a functional portion, wherein the casings are configured to be guided with greater play in the transitional portion than in the functional portion, wherein a first casing of the casings has a guide track and a second casing of the casings has a guide element that is configured to engage in the guide track, wherein the guide element is configured to be guided in the length direction and is configured to have a guide play in the guide track that is greater in the transitional portion than in the functional portion.

17. The steering column of claim 16 wherein the guide track and the guide element constitute a form-fit connection that is active in a circumferential direction.

18. The steering column of claim 16 wherein the guide play between the guide track and the guide element exists in a circumferential direction.

19. The steering column of claim 16 wherein the guide track has an elongate guide groove in which a guide protrusion of the guide element engages, with some portions of the elongate guide groove having a smaller groove width than another portion.

20. The steering column of claim 16 wherein the guide track has an elongate guide protrusion that is configured to engage in a guide recess of the guide element, with some portions of the elongate guide protrusion having a greater web width than another portion.

21. The steering column of claim 16 wherein the guide play is smaller at a first end portion and/or a second end portion of the guide track.

22. The steering column of claim 16 wherein at least one of: the guide track includes a guide track body; or the guide element has a guide element body that is arranged or formed on one of the casings.

23. The steering column of claim 22 wherein at least one of the guide track body or the guide element body are formed separately and connected to one of the casings.

24. The steering column of claim 22 wherein at least one of the guide track body or the guide element body are comprised of different material than that of the casings.

25. The steering column of claim 24 wherein at least one of the guide track body or the guide element body are comprised of plastic.

26. The steering column of claim 16 wherein the casings comprise an upper casing and a lower casing.

27. The steering column of claim 26 comprising an intermediate casing disposed between the upper casing and the lower casing.

28. The steering column of claim 16 wherein the casings comprise telescopic casing tubes.

29. The steering column of claim 16 comprising a motorized adjustment drive that is coupled to the casings to adjust the casings relative to one another.

30. The steering column of claim 16 comprising an energy absorption device disposed between the guide track or the guide element and one of the casings.

Description

DESCRIPTION OF THE DRAWINGS

[0028] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In the drawings:

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

[0030] FIG. 2 shows the steering column from FIG. 1 in a further perspective view,

[0031] FIG. 3 shows the steering column from FIG. 2 in a partially expanded view,

[0032] FIG. 4 shows an enlarged extract from FIG. 3,

[0033] FIG. 5 shows a cross-section Q-Q through the steering column from FIGS. 2 and 6,

[0034] FIG. 6 shows the steering column from FIGS. 1 and 2 in a partly cutaway side view,

[0035] FIG. 7 shows an enlarged detail view of the guide device from FIG. 6,

[0036] FIG. 8 shows a guide device in a second embodiment, in a view similar to FIG. 7.

EMBODIMENTS OF THE INVENTION

[0037] In the various figures, the same parts always carry the same reference signs and are therefore usually only cited or mentioned once.

[0038] FIGS. 1 and 2 shows a steering column 1 according to the invention in various perspective views, diagonally from the left rear (FIG. 1) and diagonally from the right rear (FIG. 2) relative to the direction of travel, and FIG. 3 shows a partially expanded illustration, exploded transversely to the direction of travel.

[0039] FIG. 3 shows a partially schematic cutaway steering column 1 in a view from the left (the side visible in FIGS. 2 and 3) and FIG. 4 shows an enlarged view thereof. FIG. 5 shows a cross-sectional view Q-Q according to FIG. 6 or 2.

[0040] The steering column 1 comprises a two-piece carrier unit 2 with fixing means, namely fixing openings 21 for attachment to a vehicle body (not shown).

[0041] A casing unit 3 is held by the carrier unit 2 and, on the body side at the front in the direction of travel, comprises an outer casing 31, also described as the lower casing, and an inner casing 32, also described as the upper casing. A steering spindle 33 is mounted in the inner casing 32 so as to be rotatable about a longitudinal axis L extending in the length direction, and at its rear end portion has a connecting portion 34 for attachment of a steering wheel (not shown).

[0042] The inner casing 32 is configured as a casing tube with a base body with round tube cross-section, and for length adjustment is received in the outer casing 31 and is telescopically adjustable in the length direction as indicated by the double arrow. In a set position, an operating or control position as shown in the figures, the casing is extended relatively far out of the outer casing, i.e. to the right in FIG. 1 and to the left in FIGS. 2 to 4, and 6 to 8.

[0043] For length adjustment, a motorized adjustment drive 5 is provided, configured as a spindle drive with a spindle nut 52, which is supported in the length direction on the outer casing 31 and is able to be driven rotationally by an electric motor 51, and engaging therein a threaded spindle 53 which extends in the length direction and is fixed to the inner casing 32 rotationally and in the length direction.

[0044] A guide device 4 according to the invention comprises a guide track in which a guide groove 41 is formed which is elongate in the length direction. This guide groove 41 has a groove cross-section open radially to the longitudinal axis, also called a guide cross-section, and is formed in a guide track body 42. which is fixed to the outer casing 31 in the length direction and in the circumferential direction relative to the longitudinal axis L by means of a carrier element 43.

[0045] A guide element in the form of a guide protrusion 44 is fixed in the length and circumferential directions and protrudes radially relative to the longitudinal axis L. The guide protrusion 44 has the form of a peg which is elongate in the length direction and has a width G measured transversely to the length direction, i.e. in the circumferential direction. The guide protrusion 44 protrudes radially outward from a guide element body 45 and engages from the inside in the guide groove 41 such that it is force-guided movably in the length direction, i.e. is supported by form fit in the circumferential direction.

[0046] The guide track body 42 may be formed from a plastic at least in the region of the guide groove 41. Alternatively or additionally, the guide protrusion 44 may be made of a plastic at least in the region of contact with the guide groove 41. Alternatively, a metal may be used, or the guide track body 42 may be formed from a metal, for example as a casting or extrusion.

[0047] In normal operating state, the guide element body 45 is fixed on the outside of the inner casing 32 in the length and circumferential direction via an energy absorption device 6. The energy absorption device 6 has a profile rail 61 which is fixedly arranged on the inner casing 32 and has a slot 62 which is elongate in the length direction. A bolt-like expansion element 63 is pressed into said slot 62 and protrudes on the inside of the guide element body 45 facing away from the guide protrusion 44. Because the expansion element 63 has an oversize relative to the width of the slot 62 and is pressed into the slot 62 with local deformation, the guide element body 45 is fixed in the length direction to the inner casing 32 via the profile rail. The threaded spindle 53 of the adjustment drive 5 engages on the inner casing 32 via this guide element body 45 and the absorption device 6 for length adjustment. Only in the case of a crash, when the inner casing 32 is pushed into the outer casing 31 with an extremely high force, is the expansion element 63 pushed through the slot 62 in the length direction under plastic expansion, as indicated in FIG. 4 with the arrow, wherein kinetic energy is absorbed.

[0048] In normal adjustment mode, the guide protrusion 44 is guided slidingly in the guide groove 41, as is clearly evident in the cross-section Q-Q of FIG. 5.

[0049] In FIG. 6 and in the enlarged illustration of FIG. 7, for greater clarity, the carrier element 43 has been omitted and the carrier element body 42 schematically cut open longitudinally, i.e. illustrated radially opened from the outside, to give a view of the guide groove 41 which would otherwise be closed towards the outside.

[0050] According to the invention, the guide groove 41 has a functional portion A which extends over a part portion of its length corresponding to the operating range illustrated, in which the casings 31 and 32 can be adjusted in the length direction relative to one another in order to set the steering wheel position. In the functional portion A, the guide groove 41 has a groove width W1 measured in the circumferential direction transversely to the longitudinal axis L. This groove width W1 is matched with a slight guidance play to the width G of the guide protrusion 44 so that the guide protrusion 44 is guided slidingly in the length direction and the guidance produces a high stiffness of the casing unit 3. The amount of guide play results from the difference W1−G. In the insertion direction indicated by the arrow on the guide protrusion 44, and in which the inner casing 32 is moved into the outer casing 31 on retraction, a transitional portion B adjoins the functional portion A. The total possible adjustment travel substantially corresponds to the sum of portions A+B. The groove width W2 in this transitional portion B according to the invention is greater than the groove width W1. Therefore a greater guide play exists between the guide protrusion 44 and the inner flanks of the guide groove 41 transversely to the longitudinal axis L, measured in the circumferential direction, with the amount W2−G. W1<W2. Thus on retraction, outside the functional portion A when entering the transitional portion B, there is a loose form fit of the guidance so that the friction of the guidance is lower. The resulting lower stiffness of the casing unit 3 is acceptable since the transitional portion B is used only briefly on stowage into the retracted stowage position and on extension into the operating position, wherein no actuation of the steering takes place.

[0051] Preferably, in the transitional portion B, the guide protrusion 44 also has a distance from the groove base of the guide groove 41, and in the functional portion A the guide portion 44 has contact with the groove base of the guide groove 41, as shown in FIG. 5. Thus the play between the guide protrusion 44 and the guide groove 41 is determined not only by the contact of the guide protrusion 44 on the groove flanks of the guide groove 41, but also by the contact or play existing between the guide protrusion 44 and the groove base of the guide groove 41.

[0052] In the refinement shown in FIG. 8, at the other end region of the adjustment travel opposite the functional portion A, adjoining the transitional portion B is a further functional portion C which corresponds to a retracted stowage position. The total possible adjustment travel thus substantially corresponds to the sum of portions A+B+C. In the stowage range C, the guide groove 41 has a groove width W3 which is smaller than the groove width W2 in the transitional portion B, allowing a low-play guidance and holding in the stowage position. W2>W3. The stiffness in the stowage range C is not as decisive as in the operating range A, so W3 may be greater than W1, and W2>W3>W1. It may also be provided that W1=W3 and W2>W3 and W2>W1.

LIST OF REFERENCE SIGNS

[0053] 1 Steering column [0054] 2 Carrier unit [0055] 21 Fixing openings [0056] 3 Casing unit [0057] 31 Outer casing [0058] 32 Inner casing [0059] 33 Steering spindle [0060] 34 Connecting portion [0061] 4 Guide device [0062] 41 Guide groove [0063] 42 Guide track body [0064] 43 Carrier element [0065] 44 Guide protrusion [0066] 45 Guide element body [0067] 5 Adjustment drive [0068] 51 Motor [0069] 52 Spindle nut [0070] 53 Threaded spindle [0071] 6 Energy absorption device [0072] 61 Profile rail [0073] 62 Slot [0074] L Longitudinal axis [0075] G Width of guide protrusion 44 [0076] A, C Functional portion [0077] B Transitional portion [0078] W1 Groove width A [0079] W2 Groove width B [0080] W3 Groove width C