STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column may include a casing tube in which a steering spindle is rotatably mounted, a guide unit that receives the casing unit so as to be telescopically adjustable in a direction of a longitudinal axis, and an electromotor adjustment drive that is arranged between the casing tube and the guide unit. An inner bearing face of the guide unit surrounds an outer casing surface of the casing tube and includes a slot extending longitudinally with a slot width between mutually opposing slot edges. A preload device engages the slot edges and is configured to apply a tightening force to reduce the slot width to preload the bearing face together with the casing surface. A clamping body cooperates with the slot edges via a deflection device that converts a reduction of slot width into a radial clamping movement of the clamping body for radial preloading the outer casing surface.

Claims

1.-11. (canceled)

12. An electrically adjustable steering column for a motor vehicle, comprising: a casing tube in which a steering spindle is mounted so as to be rotatable about a longitudinal axis; a guide unit that is connectable to a body of the motor vehicle, wherein the casing tube is received in the guide unit so as to be telescopically adjustable in a direction of the longitudinal axis, wherein an inner bearing face of the guide unit surrounds an outer casing surface of the casing tube and has a slot that extends in the direction of the longitudinal axis and that has a slot width between mutually opposing slot edges; an electromotor adjustment drive disposed between the casing tube and the guide unit; a preload device that engages the mutually opposing slot edges of the slot and is configured to apply a tightening force to reduce the slot width to preload the inner bearing face together with the outer casing surface; and a clamping body that cooperates with the slot edges via a deflection device that converts a reduction of the slot width into a radial clamping movement of the clamping body for radial preloading the outer casing surface of the casing tube.

13. The electrically adjustable steering column of claim 12 wherein the clamping body is disposed in a region of the slot between the slot edges and the outer casing surface of the casing tube.

14. The electrically adjustable steering column of claim 12 wherein the clamping body includes a first control face that cooperates with and corresponds to a second control face on the guide unit.

15. The electrically adjustable steering column of claim 14 wherein the first or second control face includes a wedge face that slopes against a circumferential direction and runs parallel to the longitudinal axis, the wedge face contacting a corresponding support face on the guide unit or on the clamping body.

16. The electrically adjustable steering column of claim 14 wherein the clamping body comprises two wedge faces that are arranged mirror-symmetrically with respect to a longitudinal plane and extend together radially towards an outside, wherein the two wedge faces are disposed between corresponding support faces on the guide unit.

17. The electrically adjustable steering column of claim 12 wherein the clamping body includes a slide face directed radially against the outer casing surface.

18. The electrically adjustable steering column of claim 12 wherein the clamping body includes a lubrication pocket.

19. The electrically adjustable steering column of claim 12 wherein the clamping body is comprised of plastic.

20. The electrically adjustable steering column of claim 12 wherein the clamping body is supported on the guide unit in the direction of the longitudinal axis.

21. The electrically adjustable steering column of claim 12 wherein the preload device includes a tightening bolt that extends over the slot transversely to the longitudinal axis and acts in a circumferential direction in a region of the slot edges.

22. The electrically adjustable steering column of claim 12 wherein the clamping body is supported on a tightening bolt in the direction of the longitudinal axis.

Description

DESCRIPTION OF THE DRAWINGS

[0029] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. The drawings show:

[0030] FIG. 1 an electrically adjustable steering column according to the invention in a schematic, perspective view,

[0031] FIG. 2 an enlarged, detail view of the steering column from FIG. 1,

[0032] FIG. 3 a detail view similar to FIG. 2, in partially exploded illustration,

[0033] FIG. 4 a cross-section through the steering column from FIG. 1,

[0034] FIG. 5 an enlarged, detail view of the cross-section from FIG. 4 in a first embodiment,

[0035] FIG. 6 an enlarged, detail view of the cross-section from FIG. 4 in a second embodiment.

EMBODIMENTS OF THE INVENTION

[0036] In the various figures, the same parts always carry the same reference signs and are therefore usually only cited or mentioned once.

[0037] FIG. 1 shows a schematic, perspective view of an electrically adjustable steering column 1 in the installation position, obliquely from the rear onto the left-hand side in the direction of travel.

[0038] The steering column comprises a carrier unit 2 with connecting means 21 in the form of bolts for mounting to a body (not shown) of a motor vehicle.

[0039] The carrier unit 2 holds a casing unit 3 comprising a steering spindle 31 which, at its rear end in the direction of travel, has a fixing portion 32 for attachment of a steering wheel (not shown), and which is mounted in a casing tube 33 so as to be rotatable about a longitudinal axis L. The casing tube 33 is received in a longitudinal opening 35 so as to be telescopically adjustable in the longitudinal direction, i.e. in the direction of the longitudinal axis L, as indicated by the double arrow.

[0040] The guide unit 34 is mounted on the carrier unit 2 in the front region, so as to be pivotable about a vertical pivot axis 22 lying horizontally and transversely to the longitudinal axis L, whereby the casing unit 3 can be adjusted up and down in a vertical direction H relative to the carrier unit 2 for height adjustment of the steering wheel, as indicated by the double arrow.

[0041] In the cross-sectional view A-A from FIG. 1 shown in FIG. 4, it is evident how the casing tube 33 is held coaxially in the opening cross-section of the longitudinal passage 35. The guide unit 34 here surrounds the casing tube 33 with radially inwardly directed bearing faces 36, which each extend over a circumferential region in the longitudinal passage 35 and, in the example illustrated, are divided into several radially inwardly protruding, circumferential portions. The bearing faces 36 lie on the outside of the outer casing surface of the casing tube 33 so as to slide in the longitudinal direction.

[0042] The guide unit 34 has a slot 4 running in the longitudinal direction, with a slot width which extends between two mutually opposing slot edges 41 in the circumferential direction.

[0043] A preload device 5 comprises a tightening bolt 51 which is configured as a threaded bolt with a bolt head 52 and a threaded portion 53 on which a nut 54 is screwed. The tightening bolt 51 passes through the guide unit 34 transversely to the longitudinal axis L and extends over the slot 4. Because the bolt head 52 rests on the outside of the guide unit 34 relative to the one slot edge 41, and the nut 54 rests on the outside of the guide unit 34 on the opposite side relative to the other slot edge 41, the two slot edges 41 can be moved towards one another in the circumferential direction with a tightening force S by tightening the nut 54, as shown in FIG. 4 and the enlarged detail view of FIG. 2. In this way, the slot width of the slot 4 can be set by adjustment of the nut 54.

[0044] A clamping body 6 according to the invention is arranged in the region of the slot 4. A radially inwardly facing slide face 61 of this body rests on the outer casing surface of the casing tube 34.

[0045] The slide face 61 of the clamping body may be provided with a friction-reducing coating, for example a slip paint.

[0046] The clamping body 6 has a prismatic or ridge-like cross-section which has two wedge faces 62 sloping towards one another, which run together radially towards the outside. The two wedge faces 62 are arranged mirror-symmetrically with respect to a longitudinal plane containing the longitudinal axis L, and extend in the longitudinal direction parallel to the longitudinal axis L.

[0047] The wedge faces 62 bring the clamping body 6 into sliding contact with corresponding support faces 42, which are formed on the inside of the guide unit 34 on both sides of the slot 4 in the region of the slot edges 41.

[0048] The wedge faces 62 together with the support faces 42 form a deflection device according to the invention, namely a wedge or curve gear, which may also be described as a wedge or curve guide. A reduction in slot width in the circumferential direction is converted into a radially inwardly directed clamping movement via the sloping support faces 42 and wedge faces 52, whereby the sliding face 61 of the clamping body 6 is preloaded with a preload force F radially from the outside against the outer casing surface of the casing tube 33.

[0049] By screwing the nut 54 onto the tightening bolt 51, the tightening force S for reducing the slot width may be set, whereby the preload force F exerted on the casing tube 33 by the clamping body 6 can be finely adjusted. In this way, the bearing play of the sliding guide between the casing tube 33 and the bearing faces 36 of the guide unit 34 and clamping body 6 can easily be optimally set.

[0050] It may be provided that the nut 54 and the tightening bolt 51 are inseparably connected together. This may be achieved for example by means of a substance-bonded connection such as welding or gluing, or by plastic deformation by means of a caulking operation or similar.

[0051] FIG. 5 shows an enlarged, part view of the cross-section from FIG. 4 in which the arrangement of the clamping body 6 is clearly evident. FIG. 6 shows a similar view of a refinement in which a lubrication pocket 63 is formed as a depression in the region of the sliding face 61, and can be filled with grease for long-term lubrication.

[0052] The length adjustment by telescopically retracting or extending the casing tube 33 relative to the guide unit 34 takes place by means of an electric motor length adjustment drive 8, which may be configured in the known fashion as a spindle drive which is integrated or arranged between the casing tube 33 and the guide unit 34 in the longitudinal direction.

[0053] For support on the guide unit 34 in the longitudinal direction, the clamping body 6 on its top side has a form-fit cutout 64 which can be seen in the illustration of FIG. 3, in which the tightening bolt 51 is shown removed. For mounting, the tightening bolt 51 is passed through the openings 37 formed on the guide unit 34 on both sides of the slot 4, and thus engages in the form-fit cutout 64 in order to form a form fit acting in the longitudinal direction. Optionally, flanged sleeves may be arranged in the openings 37, wherein preferably the flanged sleeves are made of a non-ferrous metal such as brass. Thus the clamping body 6 is held on the guide unit 34 by form fit in the longitudinal direction.

[0054] For height adjustment, an electric motor adjustment drive 7 is provided, formed as a spindle drive which rests on the guide unit 34 and acts on an adjustment lever 71 which is itself mounted on the guide unit 34 so as to be rotatable around the tightening bolt 51. A lever end 72 of the adjustment lever 71 is hinge-mounted on the carrier unit 2. In this way, a pivoting of the adjustment lever 71 by means of the adjustment drive 7 causes a height adjustment by pivoting the casing unit 3 about the vertical pivot axis 22.

[0055] In an embodiment not shown, it may be provided that the adjustment lever 71 is rotatably mounted on the guide unit 34 by means of a hinge axis, wherein the tightening bolt 51 is not formed by the hinge axis. It is furthermore pointed out that a height adjustment is not essential to the invention, and the teaching of the invention can also be implemented with a steering column which is purely length-adjustable.

LIST OF REFERENCE SIGNS

[0056] 1 Steering column [0057] 2 Carrier unit [0058] 21 Connecting means [0059] 3 Casing unit [0060] 31 Steering spindle [0061] 32 Fixing portion [0062] 33 Casing tube [0063] 34 Guide unit [0064] 35 Longitudinal passage [0065] 36 Bearing faces [0066] 37 Openings [0067] 4 Slot [0068] 41 Slot edge [0069] 42 Support faces [0070] 5 Preload device [0071] 51 Tightening bolt [0072] 52 Bolt head [0073] 53 Threaded portion [0074] 54 Nut [0075] 6 Clamping body [0076] 61 Slide face [0077] 62 Wedge faces [0078] 63 Lubrication pocket [0079] 64 Form-fit cutout [0080] L Longitudinal axis [0081] S Tightening force [0082] F Preload force