WO1989012179A1

WO1989012179A1 - System for assembling a drive element connected to a driven element

Info

Publication number: WO1989012179A1
Application number: PCT/FR1988/000276
Authority: WO
Inventors: Jean-Pierre Eckendorff
Original assignee: Eckendorff Jean Pierre
Priority date: 1988-06-02
Filing date: 1988-06-02
Publication date: 1989-12-14
Also published as: EP0420840A1; ES2016141A6; JPH03504581A

Abstract

In the assembly of a drive element, such as the hub (11) of a motor vehicle steering wheel, with a driven element, such as a steering column (10), a device for the angular adjustment of the relative position of the two elements consists of an angular adjusting ring (20) linked with an angular screw (25) for controlling the axial movement of said ring, along coupling grooves between the ring and column. Said adjusting ring (25) has a straight-cross section external surface with a generally polygonal form, with helicoidal surfaces which cooperate with an internal surface of the hub of complementary shape, radial projections (28) offering in addition support edges of essentially radial orientation. The angular adjustment device thus formed can be advantageously combined with a complementary device for axial adjustment of the radial position of the assembled elements.

Description

"System for assembling a driving element coupled to a driven element" The invention generally relates to a system for assembling a driving element coupled to a driven element, capable of being driven in rotation. It may be, for example, the assembly of the steering wheel of a motor vehicle and an associated steering column.

We know that in such an assembly can often arise the problem of adjusting the relative position of the two elements once assembled. In fact, it can be the angular relative position, on the one hand, and / or the axial relative position, on the other hand.

The Applicant has already described, in particular in EU-A-0 148 794, for an assembly system of the type under consideration, a device for adjusting the angular position of the driving and driven elements, comprising a ring interposed with respectively internal and exterior comprising groove means capable of cooperating with complementary means that comprise said elements to thereby form two couplings, at least one of these having helical grooves. This ring was associated with a translational control means, so that a translational movement of this ring drives one of the elements in angular displacement. The control means in question was advantageously constituted by a screw with an axis parallel to the axes of rotation of the assembled elements and by cooperation with the ring, on the one hand, and the driving element, on the other hand, was capable of ensuring , by a controlled rotation, the translation of the ring. The element carrying the ring was for example a steering column of a motor car, while the other element formed the hub of the steering wheel assembled with said column.

The control screw was advantageously annular and coaxial with the two elements, engaged by its inner surface with a heel formed for this purpose on an axial extension of the ring and by its outer surface threaded with the threaded hub for this purpose, the steering column-ring coupling comprising rectilinear grooves, while the ring-hub coupling included at least one, but preferably, a series of helical grooves. The general object of the present invention is an advantageous development of assembly systems thus known, in particular in their applications to the assembly of the hub of a steering wheel of a motor vehicle with an associated steering column, but without any exclusion of others. applications, such as assembling a timing pinion and a camshaft.

A more particular object of the invention is a reduction in the play that may occur within the assembly while facilitating the manufacture and the assembly of the constituent parts thereof.

Another object of the invention is the combination of angular adjustment with an axial adjustment of the relative position of the assembled elements.

The present invention comprises, as a starting point, a particular embodiment which had proved particularly advantageous in practice among the various embodiments of the aforementioned prior angular adjustment device; it is an angular adjustment ring having a cross section of generally polygonal shape with helically developing sections in cooperation with an internal surface of complementary shape to the driving member, in particular the hub, while the coupling with the driven member, in particular the steering column, is of the type with longitudinal grooves. Experience has shown that the angular adjustment ring thus designed, explicitly mentioned for the first time in the publication JP 244665/1986 of the applicant, lent itself to a particularly economical manufacture, while offering ease of assembly and great security.

Normal conditions of manufacture by a suitable process of continuous extrusion of this type of ring have, however, revealed the practical need to accept tolerances likely to lead to a certain play in the coupling produced by the helical flanges with the correspondingly shaped internal surface of the hub. However, this play in the coupling with the driving element, in particular hub, is added to the existing play and conventionally tolerated in the splined coupling on the driven element, in particular steering column.

Hence the interest of the first specific object of the present invention consisting in reducing the clearance in the coupling of the adjustment ring in question with the driving element, in particular the steering wheel hub.

The means proposed for this purpose by the invention is the arrangement, according to at least some of the edges of the cross section of polygonal shape of the angular adjustment ring, of a radial projection providing between two sides of substantially radial orientation, a circular peripheral surface.

One will thus find, on or between at least some of the sides of the ring, such a radial projection connecting to a straight part, while on the internal surface of complementary shape of the driving element (hub) a hollow molding of corresponding section will of course be arranged in regad of each radial projection of the ring, these moldings alternating with straight sides, all in helical development. The coupling thus produced between the angular adjustment ring and the driving element therefore involves the cooperation of two systems of bearing surfaces with helical development: on the one hand, the tangential orientation surfaces which are generated by the sides of the polygonal section, and, on the other hand, the radially oriented surfaces which are generated by the sides of the projections. In other words, these projections form with the corresponding moldings of the hub a coupling of the helical groove type, while the sides of the polygonal section carry out a coupling by interlocking of the two complementary helical structures.

Experience shows that this combination of two distinct types of mating is a means of very considerable reduction in clearances, without it being necessary to increase the severity of manufacturing tolerances, in particular by extruding a profile from which the adjusting rings can be obtained by simple cutting, this cutting being followed by '' machining of the axial extension with retaining heel of the annular control screw.

This association also makes it possible, by a judicious choice of the radial development of the projections associated with the right sides of the adjustment ring, to limit the local stresses applied to the internal surface of the hub when the latter is made of light material, aluminum for example.

The shape of the right sides leads to give the tapping of the hub, intended to receive the thread of the control screw, a particularly advantageous shape because it avoids the burrs that otherwise appear during tapping.

According to another aspect of the invention, an angular adjustment device of the kind considered is combined with an axial adjustment device of the relative position of the two assembled elements.

In the case of a driving element, such as a steering wheel hub, assembled with a driven element such as a steering column, a threaded ring for axial adjustment screwed inside a threaded bore of the hub being intended to cooperate with, on the one hand, a front stop of the column, and on the other hand, with an axial locking means, according to an embodiment of the present invention, the abovementioned front stop is formed on the column at the birth of a smaller diameter free end portion with longitudinal grooves carrying and guiding said axial adjustment ring followed at a certain distance from the angular adjustment ring, the hub successively having on its side a first threaded bore adapted to cooperate with said axial adjustment ring , and a second helical conformation bore cooperating with the angular adjustment ring, the axial locking means comprising a screw adapted to be screwed inside the end part of the column and pressing the hub in contact with said front stop.

According to a particularly advantageous arrangement of the invention, the axial adjustment ring has a thread with an asymmetrical sawtooth profile with a substantially straight flank of the thread.

Furthermore, the threads of the two hub bores intended to cooperate, one with the axial adjustment ring, the other with the annular screw for controlling the axial adjustment ring, have the same pitch.

Being a driving element such as a steering wheel hub, assembled with a driven element, such as a steering column, having a hollow terminal part deformable by expansion, said means being coupled to this terminal part by a splined assembly, this assembly takes place, in this case, according to the invention, by means of the angular adjustment ring itself made expandable by means of a radial slot, the hub here successively comprising a smooth cylindrical bore of diameter substantially equal to external diameter of the hollow end portion of the column in the expanded state, followed by the helical conical bore receiving the angular adjustment ring, the system further comprising a device for expanding said end portion intended to intervene when are choose the relative angular position by screwing the control screw of the angular adjustment ring, then the relative axial position by sliding of this ring on the ca column grooves.

Other advantages, characteristics and details will emerge from the explanatory description which follows, given with reference to the appended drawings given by way of example and in which:

- Figure 1 is a longitudinal sectional view of a preferred embodiment of a system according to the invention for the adjustment in angular position and in axial position of the hub of a steering wheel of a motor vehicle rotatably coupled to a steering column ;

FIG. 2 is a view similar to FIG. 1, showing the state of the system after adjusting the axial position of the hub;

- Figure 3 is a view similar to Figure 2, showing the state of the system after adjusting the angular position of the hub;

- Figure 4 is a sectional view along line IV-IV of Figure 3;

- Figures 5, 6 and 7 are detail views respectively showing the hub, the angular adjustment ring and the annular control screw thereof;

- Figure 8 is a longitudinal sectional view of another embodiment of the combined angular and axial adjustment system;

- Figure 9 is a detail view of the angular adjustment ring of Figure 8;

- Figure 10 is a sectional view of another form of expandable end portion of the steering column; Figure 11 is a view similar to that of Figure 9 showing a variant. According to the embodiment chosen and shown in Figures 1 to 7, the reference 10 designates the end part of the steering column of a motor vehicle usually comprising rectilinear grooves 10A, for example 40 regularly reported at its outer periphery and an internal thread 33 intended to receive the screw 31 of a locking means 30. The reference 11 designates a flywheel hub connected to the circle of the flywheel (not shown) via for example two diametrical branches 12, 13 partially shown in FIG. 4.

Reference 17 designates a split elastic metal ring. Its internal surface has a series of rectilinear grooves 18, of equal number and capable of fitting onto the grooves 10A of the column 10. The external surface of this ring 17 comprises a thread 19 with an asymmetrical "sawtooth" profile, and more precisely a thread of which one of the thread flanks is substantially straight. The other side is inclined for example at an angle of 12 to 15 ° relative to to the axis of the ring 17.

A cylindrical bore 15 of the hub 11 is tapped in a manner complementary to the thread of the ring 17. A stop 9 with a flat contact surface, perpendicular to the axis of the column, is defined in the form of an annular shoulder between the central part of the column and its end part of smaller diameter and comes to cooperate with the end of the ring 17 to determine the axial position of the hub 11 on the column 10. The reference 20 designates the ring for adjusting the angular position of the hub 11 on the column 10. Its external surface has a cross section of generally polygonal shape with helical development visible in FIG. 6, the right sides 29 of tangential orientation of which are supplemented by projections 28 of radial orientation delimited by substantially radial sides 81 and a substantially circular peripheral end 82.

The adjusting ring 20 is fitted on the one hand on the column 10 and secured in rotation with this column by means of the splines 20A and 10A, on the other hand inside a bore 16 whose internal surface has a helical shape molded complementary to the external shape of the ring 20. An axial displacement of this ring 20 causes an angular displacement of the hub 11: thus one can define continuously and precisely, the angular position of the means 11 on the column 10 by adjusting the position axial of the ring 20 inside the bore 16.

The axial position of the ring 20 inside the bore 16 is controlled by screwing, in a thread 40A tapped in the faces 21 of the internal surface of this bore, a control ring 25.

The ring 25 (FIG. 7) is split at 25A and is axially coupled by its internal surface to the ring 20 and movable in rotation relative to the latter. This coupling includes an annular heel 22 which extends the ring 20 axially.

This heel 22 has a peripheral shoulder 23 on which the ring 25 engages by clipping thanks to the elasticity that gives it its 25A slot. Its external surface is provided with a thread capable of meshing the threads 40A of the sides 21 of the bore 16 to the hub 11.

The control ring 25 has indentations 25B allowing it to be driven by a key of suitable shape.

Experience shows that the association, in the external surface of the ring 20 and in the complementary surface of the bore 16, of a helical structure with tangential faces 29 with a helical structure with ribs 28 makes it possible to have clearances , very reduced without having to use tolerances that are too difficult to observe economically.

In particular, the body of the ring 20 can be cut from a rough drawing bar of suitable profile. It can also be obtained by molding, in particular from sintered material.

Another advantage of this arrangement is that the stress exerted by the ring 20 on the mating surfaces of the bore 16 can be reduced: in fact, by increasing the height of the radial sides 81, the surface is increased. This makes it possible to reduce the specific pressure exerted on the material of the hub and in particular to give it a value compatible with the use of light metals such as aluminum for the production of the hub.

The threading of the thread 40A in the hub 16 only concerns flat surfaces, complementary to the sections 29 of the ring 25; it follows that the sections of thread 40A naturally end in a tapered shape, which avoids burrs at the tapping and simplifies the manufacturing process, while allowing to retain all of the bearing surfaces offered by the moldings.

The operation of such a system will now be described.

Initially, the ring 17 is assembled in the bore 15 of the hub 11, and the ring 20 associated with its control element 25 in the bore 16 of the hub 11. The ring 17 is introduced by screwing inside the bore 15, using an appropriate key, until reaching for example the position shown in the Figure 1. It is prudent to check at least the last thread of the thread at the bottom of the bore 15 to limit the stroke of the ring 17 and thus prevent its penetration into the second bore 16. The stamping of this last thread will be so that it will keep the ring 17 at a distance greater than the slight recoil it will have during the final blocking without hampering its jamming effect on the column 10 or coming into contact with the ring 20. Once the ring 17 thus positioned, the first thread of the tapping is proceeded to mating at the entrance to the bore 15 so as to trap the ring between two extreme positions.

The ring 20 and its associated control element 25 are freely introduced into the bore 16 of the hub 11, until the control element 25 engages the threads 40A of the bore. Then by rotation of the control element 25, the ring 20 is engaged in the bore 16 to the position shown in Figure 1; it is then proceeded to matting the first thread of the bore 16 to make the system non-removable. In a second step, the hub 11 with the ring 17 and the ring 20 associated with its control ring 25 thus assembled, is engaged by its rear face., Corresponding to that or opens the bore 15, on the end part of the column 10, the grooves of the rings 17, 20 fitting into the grooves 10A of the column. The hub 11 is advanced on the column 10 until the front face of the ring 17 comes to bear against the shoulder 9 of the column 10.

This position defines an initial axial position of the hub 11 relative to the column 10, in fact the position furthest from the dashboard. If this position is not that desired, with particular reference to the vehicle dashboard, this position is adjusted as described below.

The hub 11 is disengaged from the column 10 and, by means of a key inserted in the grooves 18, the ring 17 is rotated to adjust its position inside the bore 15. Next, the hub 11 is again engaged on column 10 to be in the position shown in Figure 2 which is assumed to correspond to the desired axial adjustment position.

Each rotation of the ring 17 in the bore 15 in one direction or the other will have the effect of modifying the axial position of the hub by a value corresponding to the thread pitch 19, for example by 2 millimeters, ie in the direction of approximation to the dashboard, or in the opposite direction.

It should be noted that the position of the stop 9 on the column 10 is determined so that, in the two extreme positions of the ring 17 in the bore 15, the terminal end of the column 10 never protrudes beyond the front face of the hub 11.

Thirdly, the angular position of the hub 11 is adjusted relative to the column

10, in order to position the lateral branches 12, 13 in a horizontal plane.

This adjustment is carried out by driving the control ring 25 in rotation by means of an appropriate key inserted in the indentations 25B, the hub 11 remaining in the position shown in FIG. 2. This rotary control has the effect of driving the ring 20 following a translational movement, the latter being locked in rotation by its interlocking with the grooves 10A of the column 10. This translational movement of the ring 20 imparts a rotational movement to the hub 11 taking into account the cooperation between the helical surfaces of the ring 20 and the bore 16. FIG. 3 represents the state of the system, once the angular adjustment has been completed. It will be noted that these two adjustments of the axial position, on the one hand, and of the angular position, on the other hand, remain independent of each other.

Finally, in a fourth step, the system is blocked, in particular an axial blocking intended to immobilize the ring 17 on the column 10.

The blocking device 30 essentially consists of a screw 31 which, through a washer 32, is screwed into the hollow tapped end portion 33 of the column 10. As a variant, the blocking can be ensured by a nut screwed onto a threaded end portion of the column.

The washer 32 comes to bear against the external front surface of the hub 11, the tightening of the screw 31 causing a radial tightening of the ring 17 on the grooves 10A of the column 10, and an axial tightening of this same ring 17 against the stop 9.

During the tightening operation, the elasticity of the split ring 17 and the bearing effect produced by the conical surfaces formed by the inclined sides of the thread 19, ensure a tightening of the ring on the grooves 10A of the column 10, with in particular the effect of limiting the contact pressure of the ring 17 on the stopper 9. In addition, the elasticity of the ring 17 makes it possible to obtain a continuous circumferential contact surface between all of the threads of the thread 19 and the corresponding threads of the thread of the bore 15 of the hub 11.

The preferred embodiment as described above or any other equivalent embodiment may have certain additional characteristics. The hub 11 may have an external surface of polygonal and preferably hexagonal shape in order to facilitate the welding of the arms 12, 13 of the steering wheel in any positions that may be necessary, as indicated in dashed lines in FIG. 4.

The threads of the bores 15, 16 of the hub 11 can advantageously have the same pitch, of 2 mm for example, to allow their realization, with perfect concentricity, in a single operation using an appropriate tool.

Finally, the hub 11 can advantageously be made of aluminum with the polygonal profile following a helical outline of its bore 16 produced during the molding or stretching operation of the hub. Figure 8 is a longitudinal sectional view of another embodiment of the invention for assembling a steering wheel hub of a motor vehicle on a column of management.

The end part of the steering column 100 is hollow and has a slot 10B extending parallel to the grooves 10A so as to be elastically deformable in the radial direction under the effect of an expansion means 50.

The hub 11A has, towards its end facing the dashboard and the main body of the column 100, a cylindrical bore 15A. Following this bore, there is a bore 16 suitable for receiving the angular adjustment device of the type already described. However, in this embodiment, the angular adjustment ring 20 is split at 20B so as to be elastically deformable, as indicated in FIG. 9, in which we will also note the absence of internal grooves 20A in the vicinity and on both sides. other of the slot 20B of the ring 20, as well as in the part diametrically opposite to the slot 20B.

In this example, the means for expanding the column 100 and for locking the axial position of the hub 11 on this column consists of a screw 50 of generally conical shape which, once engaged in the hollow end of the column 100 , cooperates with the internal wall of the latter machined in a complementary profile.

More specifically, the screw 50 is broken down into three parts: a screw head 51 projecting from the terminal end of the column 100, a part 52 of the screw body having a frustoconical shape extended by a terminal part 53 of cylindrical shape provided a thread 54 at its periphery.

In a complementary manner, the internal wall of the hollow terminal end of the column 100 is machined so as to present, from the end of the column, a bore 55 of conical shape extended by a bore 56 of cylindrical shape. The conical bore 55 extends over a length substantially equal to that of the part 52 of the screw 50.

Finally, the cylindrical bore which extends the conical bore 55 is tapped to cooperate with the thread 54 of the screw 50, the resulting tapping partially overflowing, if need is, on the tapered bore 55 for the passage of the screw 50.

The assembly of the hub 11A on the column 100 is carried out in the manner described below. Initially, the ring 20 associated with its control ring 25 is presented opposite the bore 16 with its slot 20B preferably located along a vertical axis and freely introduced into the bore 16 of the hub 11A, until that the thread at the outer periphery of the control element 25 engages in the threads 40A of the faces 21 of the bore 16. Then, by rotation of the control element 25 by means of an appropriate key, the ring 20 is, for example, engaged to the bottom of the bore 16. In a second step, the hub 11A and ring 20 assembly coupled to its control element 25, is engaged by the bore 15 on the part end of the column 100, so that the slot 20B of the ring is substantially opposite a slot 10B of the column. The hub 11A is advanced on the column 100 until it reaches a position which separates it from the dashboard of the vehicle by a predetermined distance. This position can for example be defined by means of a removable wedge (not shown) placed between the dashboard and the adjacent end surface of the hub 11A.

Once the axial positioning of the hub 11A has been obtained, it is preferable not to immediately adjust the angular position.

Also, in a third step, the locking screw 50 is introduced freely inside the column 100, until its threaded end 53 comes to mesh with the thread of the cylindrical bore 56 of the column 100 Then, a pre-tightening of the screw 50 is carried out until its conical part 52 forming a tightening cone comes to bear on the conical bores 55 of the column 100.

The advance of the screw 50 with the cooperation between the conical bearing surfaces of the screw 50 and of the column 100, results in a radial expansion of the column 100 rendered elastically deformable by the presence of the slot 10B. This radial expansion causes a tightening between the grooves 20A of the ring and the grooves 10A of the column 100.

The purpose of this pre-tightening is to eliminate the play inevitably present between the grooves 10A, 20A, without blocking the ring 20 which must remain movable in translation to allow the angular adjustment of the hub 11A.

In a fourth step, the angular adjustment of the hub 11A is carried out. The rotation of the control element 25 by means of an appropriate key fitted into the indentations 25B, drives the ring 20, fixed in rotation, according to a movement of rotation of the hub 11A until reaching, for example, the position shown in the figure 8.

In a fifth and final step, the final axial immobilization of the hub 11A is carried out on the column 100 by additional screwing of the screw 50 causing a new expansion. This expansion of the end portion of the column 100 leads, on the one hand, to an increasingly tight fitting between the grooves 20A of the ring 20 and the grooves 10A of the column 100, and, on the other hand, an expansion radial of the ring 20 which comes into tight contact through its external peripheral surface with the internal wall of the bore 16 of the hub 11A. The ring 20 thus blocked between the column 100 and the hub 11A ensures the axial immobilization of the latter on the column 100.

This immobilization is all the more effective that the slot 20B of the ring 20 is located substantially opposite a slot 10B of the column 100 and that the ring 20 is devoid of grooves in the vicinity of the slot 20B, in order to obtain an almost total expansion of the ring 20 correspondingly increasing its contact surface with the hub 11A.

The diameter of the bore 15 of the hub 11A is determined so that, in the locking position of the system, the wall of the bore 15 is substantially in contact with the grooves 10A of the column 100 to avoid any possibility of deformation by twisting or developing the assembled system.

It appears from the above that the ring 20 of the angular adjustment device for the hub 11A performs three functions while ensuring independence between the axial positioning and the angular adjustment. The first function is performed by the grooves 20A of the ring 20 which allow the mounting of the hub 11A on the column 100 and its axial displacement until reaching the desired position. The second function is to allow the angular adjustment of the hub 11A by its displacement in translation inside the hub. Finally the third function is to ensure under the control of the locking screw 50 the immobilization of the hub.

In the event of incomplete tightening of the screw 50, it is impossible for the flywheel 11A to disengage from the column 100, since in such a movement the hub 11A would move the ring 20 until it stops against the screw head 51 whose diameter is greater than the inner diameter of the ring. Thus, the ring 20 associated with the screw 50 provides an additional safety function.

In the example described, the threaded part 53 of the locking screw 50 is located at its internal end engaged in the column 100 and in the extension of the conical part 52 of the screw. Conversely, the conical part 52 of the screw 50 can be located towards the internal end of the screw and in the extension of the threaded part 53. Other modes and means of causing the expansion of the column 10 can be used.

FIG. 10 shows in cross section an embodiment in which the expansion of the column 10A is made possible by giving the section of the hollow part, a variable radial thickness. The introduction into such a hollow part of an expansion and blocking means similar to the screw 50 causes the radial deformation and, consequently, the expansion of the column.

FIG. 11 shows in longitudinal section an exemplary embodiment in which the blocking element is, for example, constituted by a screw 60 terminated by a thread. The part of the screw forming a tightening cone is formed by an expansion cone attached freely around the body cylindrical of the screw between the screw head and an extraction ring 63 made integral with the screw. The function of this ring, in addition to that of axially retaining the expansion cone, is to drive this cone simultaneously back from the screw during a disassembly operation of the flywheel.

The threaded end part of the screw 60 meshes with a thread of a nut 54 mounted here inside the column and secured to it. Alternatively, the threaded end portion of the screw may engage in a tapped bore of a solid portion of the column.

The expansion mode represented in FIG. 11 can be used in either of the embodiments illustrated in FIGS. 8 and 10.

FIG. 11 also shows an alternative embodiment of the angular adjustment according to the invention. In this embodiment, the control means of the ring 20 of the angular adjustment is constituted by an annular screw 125 which is in simple support on the front face of the ring 20, while the opposite face of the latter is placed at the contact of a support spring 126 incorporated in a housing provided for this purpose in the hub 110.

The invention is of course in no way limited to the particular application which has been described by way of example for the mounting of a motor vehicle steering wheel. The system advantageously applies to the assembly of any driving element with a driven element whenever there can be a problem of precise and reliable adjustment of the relative positions of these elements in the axial and / or angular direction. Another interesting field of application can be found for example in the adjustment of camshafts.

The invention is also not limited to the details of the embodiments described above by way of illustration. In terms of axial adjustment, in an embodiment of the kind illustrated in Figures 1 to 3, the bearing face 9, instead of being straight, could, of course, be constituted by the conical bearing often available on certain steering columns .

Claims

1) System for assembling a driving element, such as a hub (11) of a motor vehicle steering wheel and a driven element, such as a steering column (10), with an angular position adjustment device relative of said elements comprising an angular adjustment ring (20) cooperating with a means for controlling the axial displacement (25) of this ring along splines (2OA, 10A) for coupling between ring and column, this adjustment ring having a outer surface (26) of generally polygonal cross-section with helical developing faces, in cooperation with an internal surface (27) of complementary shape to the hub (11), characterized in that at least some of the sides of the ring have a radial projection (28) providing between two sides (81), of substantially radial orientation, a circular peripheral surface (82) and a straight part.

2) The system of claim 1, wherein the control means is a threaded ring (25) screwed into an internal thread (40A) of the straight portion (29) of the sections of the surface ^inner (40) of the means (11) characterized in that this ring is split for elastic crossing of a peripheral shoulder (23) of an axial extension (22) of the ring (20) for angular adjustment.

3) System according to claim 1, wherein the control means is a threaded ring screwed into a thread on the right side of the sides of the inner surface of the hub, characterized in that this threaded ring is in simple support on the front face of the angular adjustment ring (20), while the opposite face of the latter is in contact with a support spring.

4) System according to claim 1, 2 or 3, wherein the angular adjustment device is combined with a device for adjusting the axial relative position of the hub on the column, characterized in that it comprises a threaded ring (17) screwed inside a threaded bore (15) of the cooperating hub (11), on the one hand with a front stop (9) of the column (10) determined by an annular shoulder formed on said column at the birth of its free end portion of smaller diameter which carries the coupling grooves (10A), on the other hand with a locking means (30) immobilizing the ring (17) on the column (10 ).

5) System according to claim 4, characterized in that the hub successively comprises a first threaded bore (15) adapted to cooperate with the ring (17) for axial adjustment of a second bore (16) with helical conformation cooperating with the ring (20) for angular adjustment.

6) System according to claim 4 or 5, characterized in that the thread (19) of said ring (17) for axial adjustment has an asymmetrical "sawtooth" profile, one of the sides of which is substantially straight. 7) System according to any one of claims

4 to 6, characterized in that said axial adjustment ring (17) is split.

8) System according to any one of claims 4 to 7, characterized in that said locking means (30) comprises a clamping washer (32) bearing against the front surface of the hub (11) not engaged on the column ( 10) and a screw (31) engaged in the hollow end of the column (10).

9) System according to any one of claims 4 to 8, characterized in that the tapping of the two bores

(15, 16) have the same pitch, of the order of 2mm for example.

10) System according to claim 1, 2 or 3, wherein the angular position adjustment is combined with a device for adjusting the axial relative position of the hub on the column, characterized in that the column (10) has in its part terminal a recess (55) in which engages an expansion device (50, 60) which causes the radial expansion of the column (10) and causes the blocking of the grooves (10A) of the column in the grooves (20A ) of the angular adjustment ring (20), this ring (20) being split (20B) so that the radial expansion of the column produces a radial expansion of said ring (20) and thus secures the hub (11) on the column (10). 11) System according to claim 10, characterized in that the expansion device (50) comprises a threaded cylindrical end portion (53) located towards its internal end introduced into the hollow column (10) and cooperating with a complementary tapping practiced in a cylindrical part (56) of the internal wall of the column (10).

12) System according to claim 9 or 10, characterized in that said angular adjustment ring (20) is devoid of grooves (20A) in the vicinity and on either side of its slot (20B).

13) System according to any one of claims 9 to 11, characterized in that after blocking by the expansion device (50, 60) a cylindrical bore (15) of the hub (11) comes substantially into contact with the grooves ( 10A) of the column, the hub (11A) successively comprises a smooth bore (15A) of diameter substantially equal to the external diameter of the hollow end portion of the column (100) in the expanded state followed by the helical conformation bore receiving the angular adjustment ring (20). 14) System according to any one of claims

9 to 13, characterized in that the expansion device (50, 60) comprises a head (51, 62) having an abutment face preventing disassembly between hub and column in the event of incorrect tightening of the screw. 15) System according to any one of claims

9 to 14, characterized in that the hollowed out end portion of the column (100) has at least one slot (10B) extending parallel to the grooves (10A).

16) System according to any one of claims 9 to 14, characterized in that the hollowed out end portion of the column (100A) has a variable radial thickness which gives it the ability to deform under the action of the expansion device (50, 60).

17) System according to any one of claims 9 to 16, characterized in that the expansion device comprises a cylindrical body (60) rotating inside an intermediate body (61) of progressively section variable along its axis, the depression of which in the hollowed out end portion of the column (100, 100A) causes the expansion of this hollowed out part.