STEERING COLUMN FOR A MOTOR VEHICLE AND METHOD FOR ADJUSTING A STEERING COLUMN

Abstract

A steering column for a motor vehicle may include an inner casing in which a steering spindle is mounted rotatably about a longitudinal axis that extends in a longitudinal direction and is received in an outer casing in a slidingly adjustable manner in the longitudinal direction. A pretensioning apparatus may have a pressure piece that can be braced from an outside in a tensioning direction transversely to the longitudinal axis against the inner casing. The pressure piece is held in the longitudinal direction on the outer casing and is supported against a fixing element counter to the tensioning direction. The fixing element is fixed in a recess of the outer casing. The fixing element has a forming means that is plastically furrowed into the recess, and/or the recess has a forming means that is plastically furrowed into the fixing element.

Claims

1.-17. (canceled)

18. A steering column for a motor vehicle, comprising: an inner casing in which a steering spindle is mounted rotatably about a longitudinal axis that extends in a longitudinal direction; an outer casing in which the inner casing is received in a slidingly adjustable manner in the longitudinal direction; and a pretensioning apparatus with a pressure piece that is configured to be braced from an outside in a tensioning direction transversely to the longitudinal axis against the inner casing, wherein the pressure piece is held in the longitudinal direction on the outer casing and is supported against a fixing element counter to the tensioning direction, wherein the fixing element is fixed in a recess of the outer casing, wherein at least one of: the fixing element has a forming means that is plastically furrowed into the recess, or the recess has a forming means that is plastically furrowed into the fixing element.

19. The steering column of claim 18 wherein the forming means has a tool element configured for non-cutting forming.

20. The steering column of claim 18 wherein the forming means has a toothing.

21. The steering column of claim 20 wherein the toothing includes a toothed rib that is configured at least in portions circumferentially in a circumferential direction on the fixing element and/or in the recess.

22. The steering column of claim 20 wherein the toothing includes a toothed rib that is configured at least in portions in the tensioning direction on the fixing element and/or in the recess.

23. The steering column of claim 18 wherein the fixing element and the recess have bayonet segments that correspond to one another; that extend in each case in a segment-like manner over a circumferential sub-portion; that have at least partially forming means; that are arranged and configured to enable, in a relative insertion orientation, insertion of the fixing element in the tensioning direction into the recess; and that are plastically furrowed in the fixing element and/or the recess (61) in a locking orientation rotated relative to the insertion orientation.

24. The steering column of claim 18 wherein the recess is a continuous opening.

25. The steering column of claim 18 wherein the recess and the fixing element have a round base cross-section.

26. The steering column of claim 18 comprising a spring element disposed between the fixing element and the pressure piece.

27. The steering column of claim 18 wherein the pressure piece includes a sliding element that lies against the inner casing or a rolling element that lies against the inner casing.

28. The steering column of claim 18 comprising an electric adjusting drive that engages on the outer casing and the inner casing.

29. A method for adjusting a steering column that includes an inner casing in which a steering spindle is mounted rotatably about a longitudinal axis that extends in a longitudinal direction, an outer casing that receives the inner casing in a slidingly adjustable manner in the longitudinal direction by an adjusting force, and a pretensioning apparatus with a pressure piece that is configured to be braced from an outside in a tensioning direction with a pretensioning force against the inner casing, wherein the pressure piece is held in the longitudinal direction on the outer casing and is supported against a fixing element counter to the tensioning direction, the fixing element being fixed in a recess of the outer casing, wherein the method comprises: applying a pretensioning force onto the fixing element; detecting a measurement value correlated with an adjustment and comparing the measurement value with a reference value; and fixing the fixing element on the outer casing when the measurement value corresponds to the reference value within a predefined tolerance range.

30. The method of claim 29 comprising applying the pretensioning force linearly in the tensioning direction onto the fixing element.

31. The method of claim 29 comprising measuring as the measurement value an adjustment force for adjusting the inner casing in the outer casing.

32. The method of claim 29 wherein the fixing comprises applying a fixing force that is independent of the adjusting force onto the pressure piece relative to the outer casing.

33. The method of claim 32 wherein a forming force is applied as the fixing force between the fixing element and the outer casing, wherein the forming force connects the fixing element and the outer casing by plastic forming.

34. The method of claim 33 wherein the fixing element is fixed in the recess of the outer casing.

Description

DESCRIPTION OF THE DRAWINGS

[0051] Advantageous embodiments of the invention are explained in greater detail below on the basis of the drawings. In detail:

[0052] FIG. 1 shows a steering column according to the invention in a perspective representation,

[0053] FIG. 2 shows the steering column according to FIG. 1 in a further perspective representation,

[0054] FIG. 3 shows a detailed view of the pretensioning apparatus of the steering column according to FIG. 1 in a perspective representation,

[0055] FIG. 4 shows a longitudinal section through a pretensioning apparatus according to FIG. 3,

[0056] FIG. 5 shows the pretensioning apparatus according to FIG. 3 in a schematic, pulled apart view,

[0057] FIG. 6 shows the pretensioning apparatus according to FIG. 3 in a further perspective view.

EMBODIMENTS OF THE INVENTION

[0058] Identical parts are always provided with the same reference numbers in the various figures and are therefore also generally also stated or mentioned only once.

[0059] In FIGS. 1 and 2, a steering column 1 according to the invention is represented schematically in a perspective view obliquely from the rear (relative to the direction of travel of a motor vehicle, not shown) from above (FIG. 1) and from below (FIG. 2).

[0060] The steering column 1 can be fastened to the chassis of a motor vehicle, not represented, by means of a supporting unit (console) 2 which comprises fastening means 21 for connection to the chassis.

[0061] A casing unit 3 comprises an inner casing 30, also referred to as an inner casing tube, in which a steering spindle 31 is mounted rotatably about their longitudinal axis L which extends from the front in the longitudinal direction. A fastening portion 32 for fastening a steering wheel, not represented, is formed to the rear of the steering spindle 30.

[0062] The inner casing 31 is received to be telescopically displaceable in the longitudinal direction in an outer casing 33, also referred to as an outer casing tube, as indicated by the double arrow.

[0063] A motoric longitudinal adjusting drive 4 comprises an electric drive unit 41 with an electric motor which is supported on the outer casing unit 33 in the longitudinal direction and by means of which a thread spindle (spindle) 42 extending substantially in the longitudinal direction can be rotationally driven, which spindle is screwed into a spindle nut 43 arranged in a rotationally conjoint manner with respect thereto and is supported on the inner casing tube 31 in the longitudinal direction. As a result of this, a rotational spindle drive is realized, in the case of which the distance in the longitudinal direction between drive unit 41 and spindle nut 43 is adjustable by rotational driving of the threaded spindle 42. By activating the drive unit 41, the inner casing tube 31 can be telescopically retracted or extended relative to the outer casing unit 33 for longitudinal adjustment of the steering column 1, as is indicated with a double arrow.

[0064] A height adjusting drive 5 is, like the length adjusting drive 4, likewise formed as an electro-motive spindle drive with a motoric drive unit 51, and a threaded spindle 52 which can be rotationally driven thereby and which is screwed into a spindle nut 53. The adjusting drive 5 is arranged between the supporting unit 2 and the casing unit 3, and enables a motoric adjustment of the steering spindle 30 in height direction H.

[0065] The outer casing 33 has two pretensioning apparatuses 6 according to the invention which are arranged at a distance from one another in the longitudinal direction and which are of identical design.

[0066] The pretensioning apparatus 6 is shown in an enlarged form in FIGS. 3 and 6 in a perspective view. FIG. 5 shows a pretensioning apparatus 6 in a mounted state, and one in a schematic exploded representation. FIG. 4 shows in cut-out a longitudinal section through the casing unit 3 in the region of a pretensioning apparatus 6.

[0067] Each pretensioning apparatus 6 comprises a recess in the form of a continuous opening 61 through the outer casing 33, which opening 61 extends transversely to the longitudinal axis L in the tensioning direction S which is also referred to as the insertion direction or extension direction. A fixing element 62, a spring element formed as plate spring 63, and a pressure piece 64 are arranged in the opening 61.

[0068] It is apparent in the cross-section of FIG. 4 that the pressure piece 64 in the sliding contact lies radially from the outside against the inner casing 30.

[0069] The fixing element 62 has on its outer circumference two bayonet segments 621 which extend in each case over a circumferential sub-region and are apparent in FIG. 5 as hatched circumferential sub-regions, and toothed ribs 7 which are circumferential there in the circumferential direction, which therefore run transversely to the tensioning direction S, project to the outside and are apparent in the section from FIG. 4. A multiplicity of these toothed ribs 7 are arranged consecutively in tensioning direction S so that a type of corrugated transverse toothing is formed. The bayonet segments 621 are spaced apart in the circumferential direction by circumferential gaps 622, as is apparent in FIG. 5.

[0070] The opening 61 has on its inner circumference two bayonet segments 611 which extend in each case over a circumferential sub-region and are apparent in FIG. 5 as hatched circumferential sub-regions. These have in each case a multiplicity of toothed ribs 8 running in tensioning direction S which project radially inwards and are arranged next to one another in the circumferential direction. Circumferential gaps 612 which are molded as grooves running longitudinally in tensioning direction S into the inner wall are located between the bayonet segments 611.

[0071] For the purpose of mounting, a pressure piece 64 is inserted in tensioning direction S from outside the opening 61, wherein projections 641 projecting laterally on the pressure piece 64 engage into the circumferential gaps 612 and create a form-fitting rotation lock.

[0072] The plate spring 63 which is arranged between two washers 631 and 632 is subsequently inserted.

[0073] Thereafter, the fixing element 62 is moved into an insertion orientation in which the bayonet segments 621 are located in the circumferential region of the circumferential gaps 612 of the opening 61. Due to the fact that the circumferential sub-region of the bayonet segments 621 is smaller than that of the circumferential gaps 612, and the diameter of the base body of the fixing element 62 outside the bayonet segments 621 without the toothed ribs 7 is smaller than the diameter of the opening cross-section between the inwardly projecting toothed ribs 8 in the circumferential region of the bayonet segments 611, the fixing element 62 can be inserted in a contact-free manner in the tensioning direction S into the opening 61.

[0074] A pretensioning force F can thus be applied from outside onto the fixing element 62 which is transmitted via the plate spring 63 and the washers 631 and 632 onto the pressure piece 64 which is consequently pressed with this pretensioning force F in the sliding contact against the inner casing 30. The pretensioning force F is plotted schematically in FIGS. 5 and 6.

[0075] If the required value of the pretensioning force F is reached, the fixing element 62 is rotated about the tensioning direction S in the opening 61 by means of introduction of a forming force or forming torque, and as a result moved into a fixing or locking orientation, as indicated in FIG. 6 by the curved arrows. As a result of this, the bayonet segments 621 of the fixing element 62 are moved with a forming force acting in the circumferential direction into the bayonet segments 611 of the opening 61. In this case, the toothed ribs 7 of the bayonet segments 621 are plastically furrowed in the region of the bayonet segments 611 into the inner wall of the opening 61. As a result of this, a plastic forming is generated which generates an undetachable plastic connection of the fixing element 62 in the opening 61. As a result of this, the pressure piece 64 is tensioned durably and undetachably with the pretensioning force F generated by the plate spring 63 against the inner casing 30.

[0076] It can preferably be provided that the pressure piece 64 has latching elements 642 so that the plate spring 63 and the washers 631 and 632 are premounted on the pressure piece 64 prior to insertion into the opening 61 and are held on the pressure piece 64 by the latching elements 642. The washers 631 and 632 serve the purpose of secure fixing of the plate spring 63 on the pressure piece 64 and the purpose of improved force distribution, these thus being advantageous and can be optionally used. Other types of springs can also be combined with the plate spring, or these can be provided instead of plate springs. Moreover, more than one plate spring can also be provided, what is known as a plate spring pack.

[0077] The formation of the pressure piece 64 and the plate spring 63 and the washers 631 and 632 is not inseparably linked to the formation of the fixing element 62 and their fixing in the outer casing 33 and can correspondingly be formed in a different manner. It is thus conceivable and possible that the fixing element acts directly on the pressure piece without interconnection of a plate spring and washers or the pressure piece and the fixing element are formed as a component which is integral in one piece.

LIST OF REFERENCE NUMBERS

[0078] 1 Steering column [0079] 2 Support unit [0080] 21 Fastening means [0081] 3 Casing unit [0082] 30 Inner casing [0083] 31 Steering spindle [0084] 32 Fastening portion [0085] 33 Outer casing [0086] 4, 5 Adjusting drive [0087] 41, 51 Drive unit [0088] 42, 52 Threaded spindle [0089] 43, 53 Spindle nut [0090] 6 Pretensioning apparatus [0091] 61 Opening [0092] 611 Bayonet segment [0093] 612 Circumferential gaps [0094] 62 Fixing element [0095] 621 Bayonet segments [0096] 622 Circumferential gaps [0097] 63 Plate spring [0098] 631 Washer [0099] 632 Washer [0100] 64 Pressure piece [0101] 641 Projection [0102] 642 Latching element [0103] 641 Projections [0104] 7, 8 Toothed ribs [0105] Longitudinal axis L [0106] Tensioning direction S [0107] Pretensioning force F