SLIDING BEARING FOR A STEERING SPINDLE AND STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A plain bearing for a steering spindle of a steering column for a motor vehicle. The bearing includes an inner ring with an axially continuous bearing opening for slidably receiving the steering spindle. A prestressing element is configured to exert a prestressing force on the inner ring to clamp the inner ring on the steering spindle and thereby to assign a defined, uniform braking torque.

Claims

1.-22. (canceled)

23. A plain bearing for a steering spindle of a steering column for a motor vehicle, comprising: an inner ring with an axially continuous bearing opening configured to slidably receive the steering spindle, and a prestressing element configured to exert a prestressing force on the inner ring, to clamp the inner ring on the steering spindle.

24. The plain bearing of claim 23, wherein the prestressing element is a spring.

25. The plain bearing of claim 23, wherein the inner ring is formed from plastic, preferably as an injection molded plastic part.

26. The plain bearing of claim 23, wherein the inner ring includes a radial slot, and the prestressing element bridges over the slot and narrows the slot in the circumferential direction.

27. The plain bearing of claim 26, wherein the prestressing element is configured as a clamp and is connected in the axial direction to the inner ring.

28. The plain bearing of claim 23, further comprising an outer ring surrounding the inner ring.

29. The plain bearing of claim 28, further comprising a radial compensation element disposed between the inner ring and the outer ring.

30. The plain bearing of claim 29, comprising an elastic material overmolded over the inner ring.

31. A steering column for a motor vehicle, comprising: a rotatably mounted steering spindle, and a plain bearing configured to rotatably mount the steering spindle therein, the bearing comprising: an inner ring with an axially continuous bearing opening configured to slidably receive the steering spindle, and an outer ring surrounding the inner ring, wherein the plain bearing further comprises a prestressing element, which is configured to exert a prestressing force on the inner ring and clamp the inner ring on the steering spindle.

32. The steering column of claim 31, wherein the prestressing element is a spring.

33. A plain bearing for a steering spindle of a steering column for a motor vehicle, comprising: an inner ring with an axially continuous bearing opening configured to slidably receive the steering spindle, and a prestressing device in operative connection with the inner ring, the prestressing device configured to exert on the inner ring a prestressing force that squeezes together the bearing opening and clamp of the inner ring on the steering spindle, the prestressing device further comprising an adjuster configured to variably set the prestressing force.

34. The plain bearing of claim 33, the inner ring comprising a radial slot defined by oppositely facing circumferential ends in the circumferential direction with which the prestressing device engages.

35. The plain bearing of claim 33, the adjuster comprising an adjusting drive.

36. The plain bearing of claim 33, wherein the prestressing device comprises a spring.

37. The plain bearing of claim 34, wherein the prestressing device comprises two clamping legs spaced apart in the circumferential direction, which are connected to the circumferential ends.

38. The plain bearing of claim 37, wherein the adjuster is arranged between the clamping legs.

39. The plain bearing of claim 33, wherein the adjuster comprises at least two different pairs of engaging portions on the inner ring, between which the prestressing device is mountable.

40. The plain bearing of claim 33, wherein the prestressing device is formed as a single piece construction of molded sheet metal, with a plurality of functional elements.

41. The plain bearing of claim 33, wherein the inner ring is formed of plastic.

42. The plain bearing of claim 33, comprising an outer ring surrounding the inner ring.

43. A steering column for a motor vehicle, comprising: a rotatably mounted steering spindle, and a plain bearing configured to rotatably mount the steering spindle therein, the bearing comprising: an inner ring with an axially continuous bearing opening configured to slidably receive the steering spindle, an outer ring surrounding the inner ring, and a prestressing device configured to exert a prestressing force on the inner ring and clamp the inner ring on the steering spindle, wherein the prestressing device comprises an adjuster configured to variably setting the prestressing force.

44. The steering column of claim 42, wherein the prestressing device comprises a spring.

Description

DESCRIPTION OF THE DRAWINGS

[0069] Advantageous embodiments of the invention shall be explained more closely in the following with the aid of the drawings. Specifically, there are shown:

[0070] FIG. 1 a steering column according to the invention in a schematic perspective view,

[0071] FIG. 2 a detail view of the steering column of FIG. 1,

[0072] FIG. 3 a plain bearing of a steering column according to the invention per FIG. 1 in an axial view,

[0073] FIG. 4 a view of a plain bearing for the mounting of a steering spindle,

[0074] FIG. 5 a perspective view of the plain bearing per FIG. 3,

[0075] FIG. 6 the plain bearing of FIG. 5 in a dismantled representation,

[0076] FIG. 7 a further embodiment of a plain bearing according to the invention in a dismantled representation as in FIG. 6,

[0077] FIG. 8 a second embodiment of a steering column according to the invention in a perspective view similar to FIG. 1,

[0078] FIG. 9 a steering column according to the invention in a schematic perspective view;

[0079] FIG. 10 the steering column per FIG. 9 in another schematic perspective view;

[0080] FIG. 11 a detail view of the steering column of FIG. 9 in a schematic perspective view;

[0081] FIG. 12 a cross section A-A through the steering column of FIGS. 9 to 3 in the area of the plain bearing;

[0082] FIG. 13 the plain bearing of FIG. 12 in a separate, perspective view;

[0083] FIG. 14 the plain bearing of FIG. 13 in a dismantled representation;

[0084] FIG. 15 a second embodiment of a plain bearing according to the invention in a cross sectional view as in FIG. 12 in a first setting;

[0085] FIG. 16 the second embodiment per FIG. 15 in a second setting;

[0086] FIG. 17 the prestressing device of FIGS. 11 to 14 in an enlarged view.

EMBODIMENTS OF THE INVENTION

[0087] In the different figures, the same parts are always given the same reference numbers and therefore as a rule are also mentioned or designated respectively only once.

[0088] FIG. 1 shows a steering column 1, with an actuator 2, having an inner casing tube 21, in which a steering spindle 22 is mounted rotatably about a longitudinal axis 23. At the rear end relative to the driving direction, facing toward the driver, the steering spindle 22 comprises a fastening section 24 for the mounting of a steering wheel, not shown. In its front region, the actuator 2 is received by the casing tube 21 in a casing unit 3, also known as a guide box. At the front end of the steering spindle 22, projecting to the front from the casing unit 3, there are formed fastening means 26 for connection to an intermediate shaft of the steering system, not shown.

[0089] For its mounting on a vehicle bodywork, not shown, the steering column 1 comprises a support unit 4 with fastening means 41. In the installed condition in the motor vehicle, these fastening means 41 are situated on top; for better clarity, the representation of FIG. 1 shows a view from front bottom.

[0090] The casing unit 3 is supported between two side cheeks 42, projecting downward on either side transversely to the longitudinal axis 23, i.e., projecting upward in the representation of FIG. 1. Through the side cheeks 42 there passes a tightening bolt 51 of a tightening device, which can be brought by manual activation of a clamping lever 52 connected to the tightening bolt 51 optionally into a fixed or released position. In the fixed position, the side cheeks 42 are pressed against each other, so that the casing unit 3 is clamped by friction locking and fixed between the side cheeks 42, and the actuator 2 is clamped and fixed in the casing unit 3 by the clamping force acting on the casing unit 3. In the released position, the clamping is released by abolishing the clamping force between the side cheeks 42, and the casing unit 3 can be moved up or down between the side cheeks 42 in the height direction H for a height adjustment relative to the support unit 4, as indicated by the double arrow. For the lengthwise adjustment, the casing tube 21 of the actuator 2 can be moved forward or back in telescoping manner in the longitudinal direction L in the direction of the longitudinal axis 23 in the casing unit 3, as indicated by the double arrow.

[0091] The steering spindle 22 is generally mounted by means of roller bearings (not shown here) in the area of the rear end of the casing tube 21, and at its front end, which is received in the casing unit 3. In the front end region of the casing unit 3, a plain bearing 5 designed according to the invention is placed, mounting the steering spindle 22 rotatably in its front end region.

[0092] The plain bearing 5 comprises an outer ring 51, in which an inner ring 52 is arts ranged securely in regard to rotation about the longitudinal axis 23. FIG. 2 shows, in an enlarged detail representation, a side view of the bearing arrangement formed in the front end region of the steering spindle 22 together with the plain bearing 5. It can be seen from this that the steering spindle 22 comprises a bearing section 27, which is rotatably mounted by means of the plain bearing 5.

[0093] FIG. 3 shows an axial view from the front of the plain bearing 5 in the direction of the longitudinal axis 23, corresponding to a view from the left in FIG. 2, but without the steering spindle 22. It can be seen from this that the bearing section 27 of the steering spindle 22 is received in an axially continuous bearing opening 53 of the inner ring 52, so that the steering spindle 22 is mounted in sliding manner and rotatably about the longitudinal axis 23.

[0094] The plain bearing 5 shown in FIG. 3 is shown once more in FIG. 5 in a perspective representation, and in FIG. 6 in an exploded drawing dismantled in the longitudinal direction.

[0095] The inner ring 52 comprises the coaxial bearing opening 53, and is in turn arranged coaxially in a receiving opening 58 in the outer ring 51, as can be seen in FIG. 6. The inner ring is split in the circumferential direction by a radially continuous slot 54, so that it has a C-shaped cross section. The slot 54 is spanned in the circumferential direction by a prestressing element according to the invention, designed as a spring clip 6.

[0096] The spring clip 6 is substantially U-shaped with two legs 61, as can be seen in FIG. 6. These two legs engage in the axial direction in recesses 55 or enclose the recesses 55 by their legs 61, which pass through the inner ring 52 in the region of the mutually opposite ends at the slot 54. The spring clip 6 is preferably punched out from spring steel plate and bent, forming a spring elastic force transmission element by which a prestressing force V is generated, as shown schematically in FIG. 3. Through the recesses 55, this prestressing force V is channeled in the circumferential direction into the inner ring 51 in such a way that the mutually opposite free ends of the inner ring 52, facing each other in the slot 54 in the circumferential direction, are loaded against each other in the circumferential direction, i.e., pulled together. In other words, the prestressing force V acts to reduce the slot width. In this way, the inner ring 52 is pulled together in the fashion of a pipe clip, and the prestressing force V channeled by the spring clip 6 in the circumferential direction into the inner ring 52 is diverted into a radially inwardly directed force F, which pulls the bearing opening 53 together radially. Thanks to the radial force F, which is indicated in FIG. 3, the inner ring 52 is consequently braced by its bearing opening 53 on the bearing section 27 of the steering spindle 22.

[0097] The prestressing force V exerted by the spring clip 6 ensures a greater force F acting between the mutually sliding bearing surfaces of the bearing opening 53 and the bearing section 27. In this way, the sliding friction with regard to a rotation of the steering spindle 22 about the longitudinal axis 23 is deliberately increased, so that a damping torque opposes a manual steering maneuver. This damping or braking torque acts regardless of a possible auxiliary force assistance of the steering system, whereby a manually applied steering torque is assisted by a motor. Thanks to the design of the spring force of the spring clip 6, the prestressing force V and the resulting force F, which determines the amount of the friction and thus the damping action, can be adjusted in broad limits in order to generate the desired haptics and the steering feel.

[0098] At the free ends of the legs 61 there may be arranged barbed latching elements 62, which dig into the opposite end face of the inner ring 52 when the spring clip 6 is inserted into the recesses 55 opposite the axial adjusting direction and ensure a secure, form fitting attachment of the spring clip 6. The easy installation furthermore makes it possible to first place the inner ring 52 on the bearing section 27 of the steering spindle 22 and then to clamp the bearing opening 53 on the steering spindle 22 by axial inserting and locking of the spring clip 6. Alternatively, the spring clip 6 may be installed first, and then the inner ring 52 can be mounted in the axial direction on the bearing section 27 of the steering spindle 22. In any case, the spring clip 6 closes the slot 54 in the mounted state, so that the inner ring 52 takes on a closed ring shape, thereby achieving a better stability of the mounting and an improved eigenfrequency behavior.

[0099] The inner ring 52 is preferably fabricated as an injection molded plastic part made of thermoplastic polymer, whereby the complex shape of the inner ring 52 including the slot 54 and the recesses 55 can be easily realized.

[0100] One advantageous embodiment calls for the inner ring 52 to comprise an overmolding 56 of a rubber elastic elastomer, which can be rationally mounted in the binary injection molding process. Compensation elements 57 projecting radially outward can be formed from this elastic material, which are braced radially from the inside against the inside of the receiving opening 58, and which allow an offset of the steering spindle 22 together with the inner ring 52 in the outer ring 51 and absorb it in springlike manner.

[0101] Thanks to a form fit element in the shape of a lug 511 protruding radially inwardly from the outer ring and engaging in a form fitting manner in a corresponding recess 521 on the outside in the inner ring 52, a form fitting connection acting in regard to rotation about the longitudinal axis 23 is formed between the inner ring 52 and the outer ring 51. This ensures a firm fixation of the inner ring 52 in the outer ring 51.

[0102] In the embodiment represented in FIG. 6, the inner ring 52 comprises form fit elements 522 on its outer lateral surface, for example projections protruding radially outward, which engage in a form fitting manner in corresponding form fit elements 512 in the inner wall of the receiving opening 58 of the outer ring 51, which may be formed accordingly as indentations.

[0103] For its securing in the casing unit 3, the outer ring 51 comprises latching elements 59. These extend in the longitudinal direction and have barbed free ends, which snap into the casing unit 3 when inserted axially into corresponding latching openings 31 and secure the outer ring 51 in a form fitting manner in the longitudinal direction.

[0104] FIG. 7 shows an alternative embodiment in which the inner ring 52 has a smooth, cylindrical or conical outer casing surface 523, which can be inserted and secured in a likewise internally smooth cylindrical or conical receiving opening 58 of the outer ring 51.

[0105] FIG. 4 shows a bearing arrangement of a steering spindle 22, where a spring elastic prestressing element 63 is arranged between the outer ring 51 and the inner ring 52, so that it exerts a prestressing force V as indicated in the radial direction from the outside on the inner ring 51. In this way, the latter is compressed such that it is pressed by the bearing surface of the bearing opening 53 with a radial force F against the bearing surface in the bearing section 27 of the steering spindle 22. This can likewise accomplish a controlled increased bearing friction and thus a damping action.

[0106] The embodiment of a steering column 1 shown in FIG. 8 has in place of the manual tightening device of the embodiment of FIG. 1 electrical adjusting drives 8, each having an electrical servomotor 81 and a spindle drive 82 driven therewith. One of the adjusting drives 8 is arranged between the support unit 4 and the casing unit 3 and make possible a motorized adjustment in the height direction H, the other adjusting drive 8 acts in the axial direction between the casing unit 3 and the actuator 2, so that a motorized length adjustment can occur in the longitudinal direction L.

[0107] A plain bearing 5 according to the invention can be used for this, as for the above described manually adjustable steering column 1.

[0108] FIGS. 9 and 10 show a steering column 1, with an actuator 2, having an inner casing tube 21, in which a steering spindle 22 is mounted rotatably about a longitudinal axis 23. At the rear end relative to the driving direction, facing toward the driverlooking toward the observer at bottom right in FIG. 9 and away from the observer at top right in FIG. 10the steering spindle 22 comprises a fastening section 24 for the mounting of a steering wheel, not shown. In its front region, the actuator 2 is received by the casing tube 21 in a casing unit 3, also known as a guide box. At the front end of the steering spindle 22 in regard to the driving direction, projecting to the front from the casing unit 3, there are formed fastening means 26 for connection to an intermediate shaft of the steering system, not shown.

[0109] For mounting on a vehicle bodywork, not shown, the steering column 1 comprises a support unit 4 with fastening means 41. Furthermore, the casing unit 3 has a coupling section 33, which can be attached to the vehicle bodywork, not shown. The coupling section 33 is configured as a flexurally soft section which is elastically deformed to provide a height adjustment when the casing unit 3 is swiveled relative to the support unit 4.

[0110] The casing unit 3 is supported in the support unit 4 between two side cheeks 42, projecting downward on either side transversely to the longitudinal axis 23.

[0111] Through the side cheeks 42 there passes, transversely to the longitudinal axis 23, a tightening bolt 43 of a tightening device, having a tightening gearing 44, which can be brought by manual activation of a clamping lever 45 connected to the tightening bolt 43 optionally into a fixed or released position. In the fixed position, the side cheeks 42 are pressed against each other by the tightening gearing 44, so that the casing unit 3 is clamped by friction locking and fixed between the side cheeks 42, and the actuator 2 is clamped and fixed in the casing unit 3 by the clamping force acting on the casing unit 3. In the released position, the clamping is released by abolishing the clamping force between the side cheeks 42, and the casing unit 3 can be moved up or down between the side cheeks 42 in the height direction H for a height adjustment relative to the support unit 4, as indicated by the double arrow. For the lengthwise adjustment, the casing tube 21 of the actuator 2 can be moved forward or back in telescoping manner in the longitudinal direction L in the direction of the longitudinal axis 23 in the casing unit 3, as indicated by the double arrow.

[0112] The steering spindle 22 is generally mounted by means of roller bearings (not shown here) in the area of the rear end of the casing tube 21, and at its front end, which is received in the casing unit 3. In the front end region of the casing unit 3, a plain bearing 5 designed according to the invention is placed, mounting the steering spindle 22 rotatably in its front end region in the casing unit 3. The plain bearing 5 is shown in an axial cross sectional view in FIG. 12, as well as individually in a perspective view in the mounted state in FIG. 13 and in a dismantled exploded view in FIG. 14.

[0113] The plain bearing 5 comprises an outer ring 51, having a rectangular outer cross section in the example shown, by which it is secured in a form fitting manner in the rear end region of the casing unit 3. In the outer ring 51 there is arranged an inner ring 52 which is secured in regard to rotation about the longitudinal axis 23. As a rotation lock, the inner ring 52 has form fit elements 5210 protruding radially outward with respect to the longitudinal axis 23, which engage in a form fitting manner in corresponding recesses 5110 of the outer ring 51.

[0114] The inner ring 52 has an axially continuous bearing opening 53, in which the steering spindle 22 is mounted in sliding and rotatable manner about the longitudinal axis 23 (in a bearing section 27).

[0115] The inner ring 52, which comprises the coaxial bearing opening 53, is in turn arranged coaxially in a receiving opening 58 in the outer ring 51, as can be seen in FIGS. 12, 13 and 14.

[0116] The inner ring 52 is split by a radial slot 54, so that it has a C-shaped cross section. In the slot 54, the free circumferential ends 540 of the inner ring 52 lie against each other in the circumferential direction. In the circumferential direction, the slot 54 is spanned by a prestressing device 96 according to the invention.

[0117] FIG. 17 shows the prestressing device 96 of FIG. 14 in enlarged representation. The prestressing device 96 comprises two clamping legs 961, which face each other in the circumferential direction and are oriented with their free ends 9611 substantially radially inward toward the longitudinal axis 23. The free ends 9611 are curved in a barbed manner toward their mutually facing side in the circumferential direction.

[0118] By an adjusting device 7 according to the invention, the clamping legs 961 are joined together. The adjusting device 7 comprises a first clamping lever 962 and a second clamping lever 963, forming radial prolongations of the two clamping legs 961. An adjusting screw 71 is rotatably led through an opening in the second clamping lever 963, being braced by its head 721 against the clamping lever 963 and being screwed into the internal thread of a spindle nut 72 formed on the first clamping lever 962. The thread of the adjusting screw 71 and the spindle nut 72 is preferably configured as a metric standard thread or as a metric fine thread. In the region in which the clamping levers 962 and 963 pass into the clamping legs 961, there is arranged a supporting element 964 between the clamping levers 962 and 963, so that the first clamping lever 962 together with the one clamping leg 961 and the second clamping lever 962 together with the other clamping leg 961 respectively form a double-arm lever, which is mounted in rocker arm manner about the supporting element 964, as indicated by the curved arrows.

[0119] The adjusting screw 71 forms together with the spindle nut 72 an adjusting drive acting on the clamping levers 962 and 963, namely, a spindle drive. For the adjusting by unscrewing the adjusting screw 71 from the spindle nut 72, the clamping levers 962 and 963 are spread apart in the circumferential direction, i.e., moved away from each other in the circumferential direction, as indicated with the arrows E. In this way, the free ends 9611 of the clamping legs 961 are moved toward each other via the lever coupling, as indicated with the arrows V. If the adjusting screw 71 is turned in the reverse direction, it will be screwed out from the spindle nut 72, the clamping levers 962 and 963 will be pulled together in the circumferential direction opposite the arrow direction E, and accordingly the clamping legs 961 will be moved apart opposite the arrow direction V.

[0120] The two clamping legs 961 and the clamping levers 962 and 963 are formed together with the supporting element 964 as a single stamped and bent piece of a spring steel segment in the embodiment shown, and the spindle nut 72 is likewise formed as a single piece. Only the adjusting screw 71 is mounted as a single separate part on the prestressing device 96. In this way, a rational production can occur and good functional safety is achieved. A further benefit is that the clamping legs 961 can be formed as spring elements in the form of leaf springs, so that the free ends 9611 are elastically deformable with respect to each other in the circumferential direction, in and against the arrow direction V. Because these spring elements are arranged between the adjusting device 7 and the free ends 9611, they are in the flow of force between the adjusting device 7 and the inner ring 52.

[0121] The inner ring 52 comprises radial recesses 55, which are formed on the outside in the region of the circumferential ends 540. The clamping legs 961 engage radially from the outside with these recesses 55, while the free ends 9611 contact engaging portions 560 arranged in pairs in the circumferential direction. The two engaging portions 560 form surface sections facing away from the slot 54 in the circumferential direction, having a spacing of D1 from each other when the steering spindle 22 is received in the bearing opening 53.

[0122] Because the adjusting screw 71 is unscrewed so far from the spindle nut 72 that the ends 9611 have a spacing from each other which is smaller than the spacing D1 of the engaging portions 560, the clamping legs 961 exert a prestressing force V on the engaging portions 560 by means of the ends 9611, which is correlated with the above described arrow direction V during the pretensioning. The magnitude of the prestressing force V can be made larger by spreading the clamping levers 962 and 963 further apart by turning the adjusting screw 71. On the contrary, the pretensioning can be made smaller by bringing the clamping levers 962, 963 closer together.

[0123] Through the engaging portions 560, the prestressing force V is channeled in the circumferential direction into the inner ring 51 in such a way that the mutually opposite free circumferential ends 540 of the inner ring 52, facing each other in the slot 54, are loaded against each other in the circumferential direction, i.e., pulled together. In other words, the prestressing force V acts to reduce the slot width. In this way, the inner ring 52 is pulled together in the fashion of a pipe clip, and the prestressing force V channeled by the clamping leg 961 in the circumferential direction into the inner ring 52 is diverted into a radially inwardly directed force F, which pulls the bearing opening 53 together radially. Thanks to the radial force F, which is indicated schematically in FIG. 12, the inner ring 52 is braced by its bearing opening 53 on the steering spindle 22, so that a press fit is formed between the inner ring 52 and the steering spindle 22.

[0124] The prestressing force V exerted by the prestressing device 96 ensures a greater force F acting between the mutually sliding bearing surfaces of the bearing opening 53 and the bearing section 27. In this way, the sliding friction with regard to a rotation of the steering spindle 22 about the longitudinal axis 23 is deliberately increased, so that a damping torque opposes a manual steering maneuver. This damping or braking torque acts regardless of a possible auxiliary force assistance of the steering system, whereby a manually applied steering torque is assisted by a motor. Thanks to the setting of the adjusting device 7 of the prestressing device 96, the prestressing force V and the resulting force F, which determines the amount of the friction and thus the damping action, can be adjusted continuously in order to generate the desired haptics and the steering feel.

[0125] A changed setting of the prestressing force can also be done by changing the force channeling of the ends 9611 into the inner ring 52. As shown in FIG. 17, a further pair of engaging portions 570 can be provided, which may have a spacing D2 from each other which is different from the spacing D1, and they may have a different radial position, somewhat further to the inside, as in FIG. 17. By attaching the ends 9611 at these engaging portions 570, with otherwise identical setting of the prestressing device 96, corresponding to the same setting of the adjusting device 7, a different prestressing force can be generated and exerted. To accomplish this, a prestressing device (not shown) should be provided, in which the supporting section 964 is arranged closer to the adjusting screw 71. The rest of the configuration of the prestressing device is identical to the prestressing device 96 interacting with the first engaging portions 560, as represented in FIGS. 12 to 14 and FIG. 17.

[0126] The last described interaction for the setting of the prestressing force is utilized in a second embodiment, which is represented in FIGS. 15 and 16 in a view similar to FIGS. 12 and 17 in two different settings.

[0127] The adjusting device is realized by the interaction of a stirrup-shaped, preferably single-piece spring element 966 with different engaging portions 560, 570, as described above. The spring element 966 has clamping legs 961, such as the first embodiment described above, but unlike this it has no adjusting drive 7. The setting of the prestressing force can be done simply by attaching the ends 9611 of the clamping legs 961 either to the pair of the first engaging portions 560, as in FIG. 15, or moved radially to the pair of the second engaging portions 570, as in FIG. 16.

[0128] Thanks to the barbed configuration, the free ends 9611 of the clamping leg 961 dig in when the spring clip 96 is inserted into the recesses 55 and ensure a secure, form fitting attachment of the prestressing device 96 or the spring element 966. In the mounted state, the slot 54 is bridged by the prestressing device 96 or the spring element 966, so that the inner ring 52 takes on a closed ring shape, by which a greater stability of the mounting and an improved eigenfrequency behavior are achieved.

[0129] The inner ring 52 is preferably fabricated as an injection molded plastic part made of thermoplastic polymer, whereby the complex shape of the inner ring 52 including the slot 54 and the recesses 55, optionally with the different engaging portions 560 and 570, can be easily realized. Most especially preferable, the inner ring 52 is formed from a polyoxymethylene with carbon fibers. The carbon fibers offer the benefit of lubrication and noise reduction.

[0130] One advantageous embodiment calls for the inner ring 52 to comprise an overmolding of a rubber elastic elastomer, which can be rationally mounted in the binary injection molding process. Compensation elements projecting radially outward can be formed from this elastic material, which are braced radially from the inside against the inside of the receiving opening 58, and which allow an offset of the steering spindle 22 together with the inner ring 52 in the outer ring 51 and absorb it in springlike manner.

[0131] One embodiment of a steering column 1 not shown here comprises, in place of the manual clamping device with the manual clamping lever 45 of the embodiment in FIG. 9, electrical adjusting drives, each having an electrical servomotor and a spindle drive driven therewith. One of the adjusting drives can be arranged between the support unit 4 and the casing unit 3 and make possible a motorized adjustment in the height direction H, the other adjusting drive 8 may be arranged in the axial direction between the casing unit 3 and the actuator 2, so that a motorized length adjustment can occur in the longitudinal direction L. A plain bearing 5 according to the invention can be used for this, as for the above described manually adjustable steering column 1.

LIST OF REFERENCE NUMBERS

[0132] 1 Steering column [0133] 2 Actuator [0134] 21 Casing tube [0135] 22 Steering spindle [0136] 23 Longitudinal axis [0137] 24 Fastening section [0138] 26 Fastening means [0139] 27 Bearing section [0140] 3 Casing unit [0141] 31 Latching openings [0142] 4 Support unit [0143] 41 Fastening means [0144] 42 Side cheeks [0145] 5 Plain bearing [0146] 51 Outer ring [0147] 511 Lug [0148] 5110 Recess [0149] 512 Form fit element [0150] 52 Inner ring [0151] 521 Recess [0152] 5210 Form fit element [0153] 522 Form fit element [0154] 523 Outer casing surface [0155] 53 Bearing opening [0156] 54 Slot [0157] 55 Recesses [0158] 56 Overmolding [0159] 560, 570 Engaging portions [0160] 57 Compensation element [0161] 58 Receiving opening [0162] 59 Latching element [0163] 6 Spring clip (prestressing element) [0164] 61 Leg [0165] 62 Latching elements [0166] 63 Prestressing element [0167] 7 Adjusting device [0168] 71 Adjusting screw [0169] 72 Spindle nut [0170] 721 Head [0171] 8 Adjusting drive [0172] 81 Servomotor [0173] 82 Spindle drive [0174] 560, 570 Engaging portions [0175] 96 Prestressing device [0176] 961 Clamping leg [0177] 9611 Ends [0178] 962, 963 Clamping lever [0179] 964 Supporting element [0180] 966 Spring element [0181] V Prestressing force [0182] F Force [0183] D1, D2 Distance