WO2000069700A1

WO2000069700A1 - Mechanical device for radially fixing an element onto a shaft

Info

Publication number: WO2000069700A1
Application number: PCT/FR1999/001159
Authority: WO
Inventors: Jean-Pierre Eckenforff
Original assignee: Societe De Recherches, D'etudes Et De Valorisation
Priority date: 1999-05-14
Filing date: 1999-05-14
Publication date: 2000-11-23
Also published as: WO2000069700A8

Abstract

A device for radially fixing an element onto a shaft, whereby said shaft (1) is axially engaged in an orifice of the element (2) and non-circular profiled sections rotationally fix the element to the shaft. The element (2) comprises a radial cavity (22) which opens out onto a sector of the shaft, whereby the cavity receives a tappet (3) comprising a bearing surface to the right of said sector of the shaft (1), radial compression means (4) and elastic thrust means (5) disposed between the compression means and the tappet. The invention can be used, for example, to fix the steering wheel of a motor vehicle to the end of a steering column.

Description

"Mechanical device for radially fixing an organ on a shaft"

The present invention relates to a mechanical device for radially fixing an organ on a shaft which fits axially in this organ. More particularly, it applies to the attachment of a motor vehicle steering wheel to the end of the steering column, in particular when this steering wheel is fitted with equipment for protecting the driver in the event of a collision with an airbag known as " airbag ".

The fixing of a motor vehicle steering wheel to the end of the steering column is generally carried out by fitting a grooved bore located at the center of rotation of the steering wheel hub on the corresponding grooved end of the steering column. Airbag equipment is then attached, if necessary, to the steering wheel hub, generally by means of screws. It then covers the flywheel fixing screw or nut which is therefore no longer accessible until the equipment has been dismantled. This provision also requires that the steering wheel and the "airbag" equipment be mounted separately and successively and excludes that they are delivered preassembled in a unit which would then be mounted in a single operation on the steering column and therefore with a significant reduction. assembly time on the vehicle assembly line.

An object of the present invention is a device for pre-assembly of the steering wheel and airbag equipment sub-assembly and the mounting of such a sub-assembly in a single rapid operation on the steering column, in a time equivalent to that of the aforementioned conventional assembly, by screw or nut, of a flywheel alone.

Another object is to adapt to the grooved ends of the existing steering columns, which therefore do not have to be modified to receive a steering wheel fitted with "airbag" equipment in place of an old simple steering wheel, when it is desired to improve safety on an existing vehicle model by adding such a device. Another object is a device for radially fixing an organ on a shaft with improved safety compared to the usual axial fixing systems of the prior art.

Another object is to axially secure the steering wheel by automatic snap-fastening on the steering column in order to avoid its accidental dislocation in the event of forgetting to tighten its final fixing screw.

Another object is to prevent the cone of the magnesium aluminum hubs from bursting by excessive axial tightening without being obliged to add a steel insert to them. Another object is to allow easy removal of the flywheel using a different principle from cones with a slight slope whose self-wedging effect creates disassembly difficulties.

Another object is to allow perfect mechanical strength of the steering wheel on the column with a single screw requiring only a minimum tightening torque significantly lower than what is currently used and can be obtained with a conventional screwdriver.

Another object is to have a complete function allowing a steering column indexing necessary for a single position also allowing simultaneously and the nesting of a single connector of all the electrical connections.

Another object is the realization of such a fixing by combination of a tightening action by radial screwing with the putting under stress of an elastic means adapted to develop a complementary action of fastening in axial orientation maintaining constantly the tension d 'assembly.

Another object is a motor vehicle steering column of simplified structure designed for the implementation of a radial fixing of the steering wheel and also allowing better accuracy of its axial position.

The invention also relates to a motor vehicle steering wheel fixing device particularly suitable for steering wheels with a cast aluminum hub. Yet another object of the invention is a device for pre-assembling a steering wheel with a radial fixing device, to industrially constitute a sub-assembly ready for rapid assembly on the chain.

The means proposed by the invention to achieve all of these objectives are set out in the appended claims.

The characteristics and advantages of the invention will become apparent from the following description of several exemplary embodiments, with reference to the appended drawings where:

- Figure 1 is an axial sectional view of a device according to a first embodiment of the invention pre-assembled in a steering wheel hub of a motor vehicle after installation on a conventional steering column adapted for this purpose;

- Figure 2 is a corresponding view in cross section along the plane II-II of Figure 1; - Figure 3 is a view similar to that of Figure 1 (partially truncated) showing the device in the complete fixing position of the steering wheel on the column;

- Figures 4 and 5 are detail views of an embodiment of the stirrup in respectively axial section along the plane IV-IV of Figure 5 and transverse along the plane V-V of Figure 4;

- Figure 6 is a view similar to that of Figure 1 according to a second embodiment of a hub equipped according to the invention in combination with a steering column designed and adapted for this purpose;

- Figure 7 is an axial sectional view of a device for pre-assembling a steering wheel with a device according to the invention;

- Figure 8 is a similar view partially showing the same device in another angular position called waiting;

- Figures 9 and 1 0 are plan views respectively corresponding to Figures 7 and 8 (arrows IX and X); - Figures 1 1 and 1 2 are sectional views along the planes XI-XI and

XII-XII respectively of Figures 7 and 8; - Figure 1 3 is an axial sectional view of a device according to a third embodiment of the invention;

- Figures 1 4, 1 5 and 1 6 are views in axial section showing in three successive positions a device according to a fourth embodiment of the invention;

- Figure 1 7 is a sectional view along the radial plane XVII -XVII of Figure 1 6; and

- Figure 1 8 is a cross-sectional view along the plane XVIII of Figure 1 7; - Figure 1 9 is a schematic view showing an elastic sub-assembly. FIRST FORM OF IMPLEMENTATION

According to the embodiment shown in FIGS. 1 to 3, one end of the steering column 1 conventionally provided with peripheral longitudinal grooves 1 1 and with a threaded axial bore 1 2, is fitted into a flywheel hub 2. This hub comprises by molding a cavity 22 forming a radial housing extending radially in the usual radial protuberance 20 and opening on the front wall 23 of the hub, being delimited by two side walls substantially parallel to the axial plane XX of the hub, a bottom wall 25 perpendicular to the column and an end wall 27 parallel thereto. The housing opens onto a sector of approximately 90 ° from the grooved surface 1 1 of the column. In the end wall 27 opens a tapped bore 28 with a flared inlet 29 on the end wall of the protrusion 20. We can still recognize the usual conical fitting surface 1 3 of the column cooperating with the corresponding cone 26 of the hub.

The device intended to equip the radial housing 22 according to the invention is essentially composed of three parts, namely a pusher 3, a control screw 4 and a stirrup 5.

The pusher 3 is a piece formed to present, opposite the column 1, a grooved support surface 31 advantageously extended by a smooth bearing surface 32, a blind bore 33 opening out with an inlet chamfer 34 on the radially external face which has two bearing surfaces 35.

The control screw 4 comprises a body adapted to be screwed into the internal thread 28 of the hub with an imprint 43 for key. It has a stud 41 adapted to fit into the blind bore 33 of the pusher with an end portion 44 forming a conical centering pilot in front of a groove 45 fitted with a spring ring 46 adapted to establish close contact with the wall of the bore 33 of the pusher. At the base of the stud 41 a frustoconical shoulder 42 is intended to cooperate with the stirrup.

The stirrup 5 is an elastic U-shaped piece made from a section of spring steel strip with two arms of unequal length on either side of a cut middle part to allow free passage of the stud 41 of the control screw. The reference 51 designates the long or external arm of the stirrup which is intended to be placed on the front side of the steering wheel, while the short or internal arm 52 comes to bear on the bottom 25 of the radial housing 22, the corresponding face of the pusher 3 showing clearance for this purpose. In the pre-assembly position illustrated in FIG. 1, the body of the pusher is pinched between the two arms 51, 52.

FIGS. 4 and 5 show an embodiment of the stirrup with a square orifice 53 for passage formed between two sections 55 of reduced thickness forming elastic bridges between bearing spans 54 intended to cooperate with the bearing spans 35 of the pusher. The reference 56 designates for its part the bearing surfaces intended to cooperate with the frustoconical shoulder 42 of the control screw.

According to yet another aspect of the invention, the usual screw for axially fixing the flywheel to the column is replaced here by part 6 also forming an axial screw suitable for tapping the column but with a head part having a groove 61 with a side 61 a for the end portion 51 b of the external face of the long arm 51 of the stirrup following a nesting cone 62. Finally on the front side of the steering wheel is provided a key imprint 63 advantageously identical to the key imprint 43 of the control screw 4.

In the pre-assembled position of the device according to the invention illustrated in Figures 1 and 2, the flywheel partially visible in Figure 2 with its hub 2, easily fits on the column 1, being assumed here that its grooves

21 are indexed relative to the axis xx of the pusher 3 and of the radial screw 4. The fluting of the bearing face 31 of the plunger therefore comes to be placed opposite the fluting 11 of the column, the pusher being held by the stud 41 and by pinching the two arms 51, 52 of the stirrup. Pusher and caliper thus preassembled are held in good place by the bottom 25 and the two side walls of the radial housing 22 which, taking into account their release mold, require the pusher to be placed in its only good operating position.

The grooved 31 and smooth 32 bearing surfaces of the pusher are at this stage at a distance greater than the diameter of the grooves 1 1 of the shaft 1 so as not to hinder the penetration of the latter into the orifice 21. On the other hand, the end 51 a of the long arm of the stirrup is located with respect to the axis of the shaft, at a distance less than the maximum diameter of the cone 62 so as to allow it to snap behind the flank 61 a, The steering wheel is thus placed on the steering column 1 previously equipped on the chain of the axial screw 6, it can be permanently fixed by tightening the radial compression means that constitutes the radial control screw 4 and this by means of the same screwdriver that has already been used to install said axial screw 6. Work on the chain can be simplified and accelerated insofar as the steering column can be delivered by its manufacturer fully equipped with screw 6 .

Starting from the pre-assembly position illustrated in Figure 1, this operation leads to the finished assembly position illustrated in Figure 3 where:

- The grooves 31 of the pusher 3 are fitted into the grooves of the facing sector of the groove 1 1 of the column 1;

- The smooth bearing surface 32 of the pusher has come into contact with the cylindrical surface of the axial screw 6; - The caliper 5 is advanced radially inward and elastically deployed to exert an axial clamping action on the bearing surface 26 of the hub on the bearing surface 1 3 of the column.

This clamping action mainly develops from the moment when the pusher 3 has itself come into abutment on the column 1. From this moment, in fact, the radial thrust exerted by the frustoconical bearing 42 of the body of the screw 4 on the bearing surfaces 56 of the stirrup produces a tilting action suggested by the arrow F in FIG. 1, during which the two arms 51 and 52 of the stirrup are gradually driven outward by tilting their bent roots around the corresponding bearing surfaces 35 of the pusher. The long arm 51 of the stirrup is thus advanced behind the bearing 61 a of the head of the part 6, while the short arm 52 comes into elastic abutment against the bottom 25 of the radial housing

22. Given the flexibility imparted to the central part of the stirrup, this tilting action can be carried out easily, that is to say with a moderate radial pressure, allowing the hub to slide on the column 1 up to 'with full interlocking of the bearing 26 on the bearing 1 3 of complementary shape to the column. The pushing action exerted by the control screw 4 is limited to the immediate vicinity of the orifice 53 of the stirrup, therefore at the top of the frustoconical bearing 42.

In a second step, the arms 51, 52 can no longer move away, the radial pressure exerted on the pusher increases rapidly, thereby ensuring its blocking against the column; the effective bearing surface on the stirrup is widened with deformation of the bottom of the stirrup until it extends over the entire surface of the frustoconical bearing 42 of the screw 4 (Fig. 3), thus decreasing the lever arm relative to the bearing surfaces 54.

Maximum deformation security for the stirrup is ensured by a stud 41 of chosen length so that its end face 47 comes into contact with the bottom 36 of the blind hole 33 of the pusher when the stirrup reaches its maximum admissible deformation: this thus avoids any risk of permanent deformation of the caliper. The easing relief of the central part of the base of the stirrup on either side of the orifice 53 for passage of the stud 43 as illustrated in FIGS. 4 and 5 is a means of promoting action. tilting of the arms 51 and 52. Such an arrangement of the stirrup is not necessary when the thickness of the strip or strip of spring steel constituting the stirrup remains below a certain threshold, of the order of 2 mm for example.

Anyway, the final tightening effect achieved is determined by the choice of the tightening torque of the torque wrench used for the radial screw 4 and also for the axial screw 6. This tightening torque is chosen according to the invention so that the bending stresses undergone by the two arms of the stirrup remain below the elastic limit of these.

The radial screw 4 being thus tightened, the mounting of the flywheel 2 on the column 1 is finished and carried out with a safety and an efficiency not only comparable, but even superior to the safety and the efficiency of a conventional axial fixing.

This superiority should firstly result from the radial clamping action developed on the grooved periphery of the column between the sector 31 covered by the pusher and the complementary sector 21 of the hub: this centripetal clamping action carried out between two complementary bearing surfaces of a belt around the fluted periphery of the column seems to constitute a characteristic, on the one hand, new in this field and, on the other hand, of great utility by allowing a total elimination of the play between grooves.

Another cause of superiority should result from the quality of axial tightening produced by the stirrup between the bearing 61 a of the axial screw head and the bearing bearing 1 3 of the column. An important aspect of this quality seems to consist in the reversibility of the tightening in the sense that the disassembly of the steering wheel remains easy, even after a long period of service: thanks, in fact, to the conservation of its elasticity, the caliper remains capable of resume its initial shape (as illustrated in Figure 1) after simply unscrewing the radial control screw 4. To separate the flywheel from the column, it suffices to unscrew the screw 4 until the end 51a is released of the long arm of the stirrup of the groove 61. The steering wheel becomes free immediately and can be removed without tensile force, which is not the case with the conical supports currently used with axial locking. Note here the usefulness of the spring ring 46 which, while allowing the relative rotation of the stud 41 within it, is fairly tightly pressed against the internal wall of the blind bore 33 to ensure, by moving back, the radial drive of pusher 3, even in the event of a strong tightening of it against the fluting of the column.

Another advantage is given by securing the automatic locking of the flywheel which, in addition to its angular hold by the grooves, can no longer disengage axially from the column thanks to the engagement of the end 51 a of the stirrup in groove 61 of the screw or nut 6. SECOND EMBODIMENT

These advantages can be further accentuated in an embodiment of the kind illustrated in FIG. 6 with a steering column specially designed for the implementation of the present invention. This figure is similar to Figure 1 with reference numbers plus

1 00 to distinguish equivalent but modified elements.

The column 1 01 adapted to receive the hub 102 no longer has any axial threading or tapping but has at its front end a head portion coming in one piece with the groove 1 61 latching and support behind the cone of engagement 1 62 for the long arm 51 of the stirrup 5.

A groove 1 1 1 extends here over the entire length of the column facing the grooves 1 31 of the plunger 1 03 of complementary shape. An abutment shoulder 1 1 3 replaces the conical fitting seat 1 3 of the previous and usual embodiment, in cooperation with a corresponding abutment bearing 1 26 which can here advantageously form an angle of the order of 45 ° with the axis since, thanks to the invention, it is possible to dispense with any conical fitting or fitting effect by means of a simple stop.

Instead of bearing surfaces with a conical abutment or shoulder, it is possible to provide radiused bearing surfaces or shoulder, taking into account small differences in diameter between the fluted part of the columns and the columns themselves.

Anyway, these bearing surfaces and abutment shoulders are advantageously supplemented according to the invention by the cylindrical fitting 1 27 extending over a certain length of the column 1 01. This makes it possible to extend the holding area of the hub on the column over the entire available length of the hub.

The distance separating the shoulder 1 1 3 from the face 1 61a from the groove 1 61 can be obtained more precisely in the case of the production of a one-piece column and can only contribute to an improvement in the quality and the correct axial position of the steering wheel.

Finally, FIG. 6 illustrates two examples of accessory means which can advantageously be provided on the clamping screw 4 to make it captive. One of these means is a clip washer 1 71 arranged in a groove in the stem of the screw upstream of the frustoconical bearing 1 41.

The other of these means is a stopper washer 17 2 forcibly engaged and immobilized on the periphery of the inlet 1 29 of the thread 1 28. Any one of these means or any equivalent means can advantageously be provided to oppose complete disengagement of the tapping control screw 28 (1 28) intended to receive it in the protuberance of the hub.

The same problem arises in the opposite direction in the case where the steering wheel is not mounted on a steering column, the screw would be tightened and would risk coming out of the internal thread 28 (Figures 1 and 2). In this case, the pusher can abut on the grooves of the hub located opposite the radial housing 22.

It is therefore appropriate that the screw 4 remains engaged at a minimum value in the internal thread 28 in order to be able to bring the pusher and the stirrup back in good place. The minimum total distance separating the grooves 31 of the pusher from the end of the screw on the cavity side 43 for the key must therefore be greater than the maximum total distance separating the grooves from the hub located opposite the face 27 into which the end of the tapping opens 28. PRE-ASSEMBLY APPARATUS

With reference to FIGS. 7 to 12, there will be described a device for pre-assembling a flywheel arranged according to one or other of the embodiments considered above of the invention.

As can be seen in FIG. 7, such an apparatus comprises as main element a cylindrical spindle 7 with a vertical axis standing on a base 71 and crossed by a spindle axis 72 carrying, beyond the base 71, a rod or control arm 73. The outside diameter of the spindle 7 corresponds to the minimum diameter of the top of the grooves of the hub 2 so as to allow the engagement of this hub until it stops on the base 71.

The spindle axis 72 has, in an upper part, a flat 74 opposite two bores 76 of the spindle each fitted with a ball 77 adapted to protrude from the diameter of the spindle by a height h (FIG.

1 1) determined by an annular abutment bearing provided for this purpose at the corresponding outlet of the bores 76.

Finally, the spindle axis carries a cylindrical head 78 adapted to bear on the terminal entry face of the spindle and having a flat 79.

Figures 9 and 1 1, on the one hand, and 1 0 and 1 2, on the other hand, show two angular positions provided for the rod 73.

In the position of Figures 9 and 1 1 the balls 77 are protruding, being supported on the cylindrical part of the spindle axis, while the flats 74 and 79 are oriented downward in these figures.

In the position of Figures 1 0 and 1 2 the rod having rotated 90 °, the flat 74 having come opposite the balls 77, they can enter inside the surface of the spindle, while the flat 79 of the spindle head came to be placed directly above said balls. This second situation corresponds to that illustrated in FIG. 8.

It is this second situation which is chosen for the fitting of the flywheel hub on the spindle, with its protuberance 20 presented opposite. of the flat 79 of the head of the spindle axis and the radial housing 22 facing the balls 77 for the moment retracted. The flywheel being fitted onto the spindle until it abuts on the base 71 thereof, the front wall 23 of the hub is placed approximately halfway up the head 78 of the spindle axis.

The apparatus returns to the active position in FIGS. 7, 9 and 1 1 by 90 ° rotation of the rod 73, so as to push the balls 77 projecting and to put the cylindrical seat 78 of the head of the spindle axis facing the end 51 a of the stirrup. It is then proceeded to the introduction into the radial housing 22 of the pusher 3 previously placed between the legs of the stirrup 5, the control screw 4 being introduced on its side automatically in the radial thread 28 of the hub with engagement of the stud 41 in the hole 33 of the pusher. The operation is then completed by screwing in the control screw 4 which automatically stops at a torque provided when the pusher 3 thus comes into contact with the balls 77 and the end 51 a of the stirrup in contact with the cylindrical seat 78.

The assembly operation being then completed, the device is finally returned automatically to its standby position in FIG. 8 by pivoting the link 73: the balls 77 can again retract and the flat 79 being brought back to face from the end 51 a of the stirrup, the flywheel fitted with the device 3-4-5 preset in its standby position can be effortlessly removed from the device. In order to ensure the conservation of this preset while avoiding any displacement of the screw 4, in particular during transport and various handling operations, there is advantageously a coating on the threads of this screw, ensuring braking of its rotation.

The distance provided between the outside diameter of the spindle head 78 and the bearing surface offered by the flat 79 corresponds to the value of the snap. The steering wheel is thus prepared for mounting on the chain, being in particular ready to snap in automatically.

In these embodiments considered above, the elastic pushing means interposed between the pusher and the radial screw forming compression means consisted of the stirrup 5 adapted to deploy axially between the bottom wall of the radial cavity 2 and the bearing surface 61 a of the latching groove 61 formed at the end of the steering column. Although offering the various advantages analyzed above, this type of arrangement is in no way limitative of the present invention: this will become apparent from the description below of other embodiments.

THIRD EMBODIMENT

In the embodiment illustrated in Figure 1 3, we recognize an arrangement similar to that of Figure 1 with, as common elements designated by the same references: - steering column 1 with head portion 6 having the groove snap-fastening 61 following the interlocking cone 62;

- flywheel hub 2 with the cavity 22 forming a radial housing;

- control screw 4 forming compression means with its stud 41 engaged in a blind bore of the pusher. We discover two differences concerning the configuration of the pushers and that of the elastic means.

The pusher designated here by the reference 203 extends from the bottom wall 25 to the immediate vicinity of the front wall 23 of the hub and has projecting on its face facing the column 1 a protruding element 230 adapted to snap into the groove 61 with an inclined face 230A comparable to that of a latch bolt. On the face of the pusher 203 which is faced with the column 1, there is the grooved part 231 and a smooth surface 232.

The elastic means interposed between this pusher 203 and the bearing surface 42 of the control screw is reduced on its side to a simple washer 205 finding support on the radially inner side on the shoulder frustoconical 42 of the body of the screw 4 and, on the radially outer side, on bearing surfaces 235 of the pusher.

In the position shown, the hub 2 is fitted onto the column 1, with the pusher 203 preset during the manufacture of the flywheel to allow the latching of the projecting element 230 in the latching groove 61.

A first safety lock is thus ensured as in the previous embodiments.

The complete locking of the hub 2 on the steering column is then ensured by compression of the pusher 203 against the facing face of the column 1 by the advance of the control screw 4 until the splines 231 and / or contact of the smooth bearing 232.

Under the effect of the stresses resulting from its deformation during this clamping action, the washer 205 exerts on the pusher an elastic clamping force which ensures the safety of the assembly.

FOURTH EMBODIMENT (Figures 1 4 to 1 6)

Figures 1 4 to 1 6 show this embodiment in a radial section view in three different situations, namely:

- In Figure 1 4, the steering wheel is assembled in the free state without constraint; - In Figure 1 5, the pusher is put under maximum pressure, locked and ready to be unlocked;

- In Figure 1 6, the pusher is in immobilization of the steering wheel on the column and axially secured.

In the hub designated here by the reference 302, there is a radial cavity 322 but with a raised bottom wall 324 and forming an asymmetrical V-profile locking notch. The socket cone 326 of the hub is recognized on the column 1 which is not visible in FIG. 1 4 but present in FIGS. 1 5 and 1 6.

The pusher 303 which is found with its grooved support face at 331 and smooth at 332 has a projection 330 on this face projecting towards the axis of the hub with a straight face 330A on the inside and an inclined face 330B on the outside, as an extension of the wall external of the pusher which is here spaced from the wall 323 of the front of the hub by a pin spring 360 said to hold and automatically reset, of which Figures 1 7 and 1 8 show an advantageous embodiment. In these figures, the resetting and retaining spring consists of a steel wire like a piano wire, the ends of which are bent in the form of hooks facing the axis of the hub.

When fitting into the two holes 391, intended to receive the arms of the spring and comprising a retaining face 392, the tip of the end 361 of the hook closes on itself and resumes its shape at the end of fitting , the end 361 bearing on the face 392, preventing any dislocation.

The spring having to exert a push along arrow A, it is advisable to put it in tension to pull it according to arrow B. To maintain this effort, the arms therefore exert a push according to arrow C balanced by a retainer at 361 in the direction hook bending curve.

To obtain the desired thrust A, the spring is therefore closed on itself during its manufacture at an acute angle at points C; the two hooks are therefore in the free state near the axis. When installing the spring as drawn, the angles in C will open, causing the thrust A by a bearing in C balanced by 361.

To improve the flexibility of the assembly, there is provided, as shown, in the center of articulation of the spring, a winding forming a turn.

Any other shape, especially in a U shape, can also be adopted to achieve the same result.

In order not to hinder the radial downward movement of the pusher during resetting, there may be provided in its front face a groove receiving the end of the turn which will be driven radially in the direction of the axis when the pressurization of the push on the axis. This radial stressing of the spring will have the effect, during rearming, of not opposing the descent of the pusher and therefore of its rearming but on the contrary of facilitating it.

The pusher has, on the other hand, projecting on its axially internal opposite wall, a trigger notch 337 adapted to fit with play in the notch or locking groove 325.

In the body of the pusher 303, there is a blind bore 333 extended by an end portion 333 'of reduced diameter.

We find a control screw 304 comparable to the control screw 4 of the previous embodiments, but mounted here in a hinge pin 340 formed for this purpose in the protrusion 320 of the hub with a radial passage 340A allowing a certain angular movement of the control screw 304, the latter having a head 343 around which the passage widens into a clearance chamber 329 at the inlet of which there is the safety retaining washer 1 72 already present in the example Figure 6.

In extension of the body of the control screw 304, there is a stud 341 engaged in the blind bore 333 of the pusher with a tapered end portion 345 ending in a conical cap 347 adapted to slide in the end portion 333 'of the bore blind, while the tapered portion 345 of the stud has a diameter slightly smaller than the internal diameter of the spring ring 346.

Finally, the elastic means interposed here between the bearing 342 of the control screw and the inlet chamfer 334 of the bore of the pusher consists of a stack 350 of Belleville washers 351, 352 of opposite taper on either side a flat washer.

In the situation illustrated in FIG. 1 5, the elastic means 350 is placed under maximum pressure by screwing the control screw 304 as far as it will go until the head 343 abuts on the journal 340, the spring ring 346 being then advanced practically to the bottom of the first part of the bore 333, while the conical cap 347 arrived near the bottom of the blind bore 333 '. The hub is shown, on the other hand, engaged on the steering column 1 until it comes to bear on the face 330A of the spur 330 on the bearing surface 61 b offered by the bottom of the groove 61.

The pressurizing of the elastic means 350 must take place before engagement of the hub on the column, the pusher 303 remaining, under the action of the retaining spring 360, immobilized by engagement of its trigger catch 337 in the locking groove 325. According to the invention, this pressurization of the device is operated in the factory, the engagement on the column 1 posing no problem, since, as it is visible in FIG. 1 5, the radially protruding stud 330 of the pusher passes without hitting the cone of engagement 62.

The establishment of the hub on the column is completed by releasing the locking: for this purpose it suffices to exert on the hub (in fact on the steering wheel) a sufficient thrust to cause, after abutment of the face 330A of the chin 330 on the bottom 61 b of the groove 61, the release of the trigger notch

337 according to the arrow F in FIG. 1 5. By relaxing the elastic means 350, the pusher is pressed against the immobilization of the steering wheel on the column and secured axially, the chin 330 now being advanced inside the groove lock 61. The disassembly of the steering wheel if necessary is very easily accomplished by unscrewing the control screw 304 to the position of FIG. 14 with complete relaxation of the elastic means 350 and relocking of the rocking pusher under the thrust of the spring 360 ensuring the automatic reset. It is advantageous to proceed immediately with the pressurization of the device by tightening the screw 304 until the head 343 stops on the journal 340: the flywheel is thus prepared for a new assembly.

Many other variants are conceivable for carrying out the invention as defined in the claims. Thus, for example, the radial compression means constituted in the above examples by a screws could, without departing from the scope of the invention, be constituted by a system with levers, cams, etc. The elastic means of thrust can, for its part, take various forms: thus the elastic means constituted by the stack of washers 350 of FIG. 1 4 may comprise a plurality of washers, at least some of which have conicities of the same direction or opposite directions, alternating or not, the thicknesses, conicities and diameters of which may be possibly different, so as to obtain the pressure and radial displacement desired, if necessary grouped in a sub-assembly within an external or internal tube; an example of such a subset is shown in Figure 1 9.

The type of fastening described, based on a radial and not an axial tightening, eliminates the risks of overload of tightening which, on tapered shanks of flywheels in light alloys, tend to cause their bursting. This risk is usually avoided by adding a steel reinforcement insert which is no longer necessary in a fixing device according to the invention. The elimination of this insert is a significant double source of savings because it also leads to a simplification and an improvement in the molding rates of the steering wheel.

In all the examples considered, therefore, a safe, reliable and rapid assembly is obtained, by simply tightening the radial compression means, of a flywheel provided with all of its accessories and in particular a device.

"airbag" pre-assembled and conditioned. This avoids the connections of the foam coating between the two elements and possible differences in color. Furthermore, insofar as the assembly grooves on the steering column allow only one position for fitting the steering wheel, according to the "coding" principle, it could be envisaged to connect all of the different electrical circuits of the "airbag" device, of the horn, of the cruise control, of the radio circuits and others, by means of at least one automatic plug-in connector which will fit when the steering wheel is fitted the column, instead of, as is common practice, having to connect individually the different connectors specific to each of these functions.

The invention is of course not limited to the details of the embodiments which have just been described by way of explanatory examples. Thus, in the case of steering wheels comprising for their axial fixing on the steering column a nut instead of a screw, it is on a blind nut that the groove 61 of FIG. 1 will be arranged with its cone engagement 62 and key fingerprint 63.

In the case where the grooves of the hub are not indexed, there will be provided on the pusher a cylindrical support sector with the diameter of the top of the grooves of the column on which it will bear directly with the tightening stress determined by the characteristics of the means. push elastic.

Claims

1 - Device for radially fixing an organ on a shaft, said shaft (1) being fitted axially in a corresponding orifice of this organ (2), non-circular complementary profiles integrating in rotation the organ with the shaft, characterized in that the member (2) comprises a radial cavity (22) opening onto a sector of the shaft, said cavity receiving a pusher (3) comprising a bearing face in line with said sector of the shaft (1) , a radial compression means (4) and an elastic pushing means (5, 205, 605) disposed between the compression means and the pusher. 2 - Fixing device according to claim 1, characterized in that the elastic pushing means is a stirrup (5) forming a spring crossed by an end stud (41) of a screw (4) forming a means of radial compression, this stud engaging in a blind bore (33) of the pusher (3), a shoulder (42) presented by the body of the screw at the root of the stud being adapted to be transmitted, via the stirrup and the push button, elastic blocking pressure on the shaft.

3 - Fixing device according to claim 2, characterized in that the stirrup (5) is a spring piece with U-shaped configuration with, on either side of a base, two arms (51, 52) respectively adapted to bear on a bearing surface (61 a) formed by a groove (61) at the end of the shaft (1) and on a bottom wall (25) of the radial cavity (22).

4 - Fixing device according to claim 3 characterized in that the base part of the stirrup comprises, on either side of a passage orifice (53) of the stud (41) an area of reduced section (55 ). 5 - Fastening device according to claim 2, characterized in that the shoulder (42) is conical.

6 - Fastening device according to claim 2, characterized in that the stud (41) has a sufficient length so that its end face (47) abuts on the bottom (36) of the blind bore (33) in order to do not exceed the expected elastic limit of the stirrup (6).

7 - A fixing device according to claim 3, characterized in that the groove (61) on the shaft (1) receiving the end of an arm (51) of the stirrup (5) is arranged in a screw head (6) screwed axially in the end of the shaft (1), in place of an axial fixing screw of the member (2) on the shaft

(1).

8 - Fixing device according to claim 3, characterized in that the groove (61) on the shaft (1) receiving the end of an arm (51) of the stirrup (5) is arranged in a cap nut screwed axially on a threaded end of the shaft (1), in place of an axial fixing nut of the member (2) on the shaft (1).

9 - A fixing device according to claims 7 or 8, characterized in that the groove (61) is preceded by an engagement cone (62) ensuring during the fitting of the member (2) on the shaft (1) the release of the end (51a) of an arm (51) of the stirrup (5) before its engagement and clipping in the groove (61).

10 - A fixing device according to claims 7, 8 or 9, characterized in that the screw or nut (6) receiving the groove (61) and the engagement cone (62) have a screwing impression identical to that of the screws (4).

11 - A fixing device according to claims 2 to 10, characterized by the association with the radial compression screw (4) of a means (161) known per se for limiting its axial movement avoiding involuntary dislocation of the stud (41 ) from its housing in the pusher.

12 - One-piece steering column adapted to be equipped by a device according to claim 1, characterized by a head part comprising at the front of a cylindrical bearing (101) a bearing bearing (113), a grooved zone (111 ) a caliper latching groove (161) and an interlocking cone (162).

13 - A device for pre-assembling a steering wheel equipped with a device according to any one of claims 1 to 11, characterized in that it comprises a cylindrical spindle (7), crossed by a spindle axis (72) carrying an arm of control (73) movable between two angular positions with means (77,78) adapted to present opposite the pusher (3), on the one hand, and the end 51a of the long arm (51) of the stirrup, on the other hand, stops for fixing predetermined radial positions for said pusher and stirrup arm.

1 4- fastening device according to claim 1, characterized in that the elastic pushing means comprises at least one washer (205) through which an end stud of a screw (4) forming radial compression means.

1 5- fixing device according to claim 1, characterized in that the elastic pushing means comprises a stack of washers (350) traversed by an end stud (341) of a screw (304) forming radial compression means .

1 6- fixing device according to claim 1, characterized by the provision at the end of the shaft of a latching groove (61) preceded by an engagement cone (62) in combination with a projecting element (230 ) of the pusher adapted to snap into said groove. 1 7- A fixing device according to claim 1, characterized by the provision at the end of the shaft of a groove (61) forming an axial abutment surface (61 b) in combination with a pusher (303) associated with a means compression (304) mounted oscillating on a pin (340) with a front projection (330) adapted to cooperate with said abutment bearing (61 b), and with a lateral projection (337) for locking, the cavity comprising a groove lock (325) adapted to cooperate with said lateral projection (337).

1 8- A fixing device according to claim 1 7, characterized by a retaining and resetting spring (360) adapted to return the pusher (303) in the position of engagement of the lateral projection (337) in the locking groove ( 325).