steering column sleeve incorporating a system for adjusting the relative position between two tubes

Abstract

The invention relates to a steering column sleeve (103) comprising two elements consisting of an outer tube (101) and an inner tube (102) movable in translation relative to each other along a reference axis (X), and at least one adjustment system (10) of a resisting force opposing a relative translational movement between the two elements (101, 102), the pressure mechanism comprising: at least one friction pad (20), supported by a first (101) of the two elements (101, 102);a clamping surface (30) integral with a second (102) of the two elements (101, 102), the friction pad (20) being configured to be in contact and bearing against the clamping surface (30), the second (102) of the two elements (101, 102) having a surface inscribed in a cylindrical envelope (E), the steering column sleeve being characterized in that the second (102) of the two elements (101, 102) comprises a guide cavity (40) extending axially with respect to the reference axis (X), the cavity (40) forming a hollow space (41) with respect to the cylindrical envelope (E), the friction pad (20) being configured to penetrate at least partially into the guide cavity (40) to guide in translation the first (101) of the two elements (101, 102) with respect to the second (102). (Fig. 5);

Description

Title of the invention: steering column sleeve comprising a system for adjusting a relative position between two tubes Technical field of the invention

[0001] The invention relates, in general, to the technical field of systems for adjusting a resistive force opposing a relative translational movement between two elements.

[0002] The invention relates more specifically to systems for adjusting a resistive force opposing a relative translational movement between two elements, these two elements being constituted in particular by an outer tube and an inner tube of a sheath of a steering column in order to allow adjustment of the position of a steering wheel, for example in depth, of a vehicle, such as a motor vehicle. State of the prior art

[0003] The steering wheels of motor vehicles are very frequently adjustable in depth and height by means of an adjustment system controlled by a user of the vehicle. Such an adjustment system generally comprises an adjustment mechanism located on a sleeve of a steering column of the motor vehicle and may be manual or electric. In the case of an electric system, an assembly consisting of a worm gear reducer associated with a screw-nut system converts the rotational movement of an electric motor into translational movement, said electric motor then being sized to achieve the desired adjustment speed taking into account the friction forces present in the steering column and more generally in the kinematic chain.

[0004] Depth adjustment is generally achieved by means of a two-tube telescopic system: an outer tube and an inner tube configured to translate inside the outer tube, said outer tube comprising a pressure mechanism such as a screw which applies a force to an inner tube. This force is necessary to mask the operating play and ensure minimum stiffness of the connection. The electric motor is then sized to achieve the desired adjustment speed taking these forces into account.

[0005] Such pressure mechanisms generally comprise a screw, screwed into a body and secured to the outer tube, provided with an interface allowing a torque and / or an angle to be applied to it and a friction pad rubbing on the inner tube. Once the various components of the mechanism are in place in the body, a tightening procedure combining torque and angle makes it possible to obtain a compressive force of a desired predetermined value that determines the pressure force applied to the inner tube by the friction pad. Such a procedure for adjusting this predetermined value is carried out once in the factory during the manufacture of the steering column. Then, during the phases of adjustment of the position of the steering wheel by a user, the effort required to carry out this depth adjustment, whether manual or electric, must overcome this predetermined force of relative clamping of the two tubes, corresponding to the clamping of the friction pad against the inner tube, in order to be able to translate them relatively one of the tubes in relation to the other.

[0006] Whatever the system used for adjusting the force resisting the relative translational movement, it is clear that the friction pads are always supplemented, on the one hand, by a system ensuring the angular guidance of the inner tube relative to the outer tube during an adjustment, and on the other hand, by a system allowing the force to be taken up when a torque is applied to the inner tube.

[0007] Both systems require additional components and manufacturing operations that generate additional costs. The result is a generally bulky, complex and expensive mechanism. Statement of the invention

[0008] The invention aims to remedy all or part of the drawbacks of the state of the art by proposing in particular an adjustment system that is simple to use, compact, and inexpensive.

[0009] To do this, according to a first aspect of the invention, a steering column sleeve is proposed comprising two elements consisting of an outer tube and an inner tube movable in translation relative to each other along a reference axis, and at least one system for adjusting a resistive force opposing a relative translational movement between the two elements, the pressure mechanism comprising: - at least one friction pad, supported by a first of the two elements; - a clamping surface secured to a second of the two elements, the friction pad being configured to be in contact and in abutment against the clamping surface, the second of the two elements having a surface inscribed in a cylindrical envelope, the sheath of the steering column being characterized in that the second of the two elements comprises a guide cavity extending axially relative to the reference axis, the cavity forming a hollow space relative to the cylindrical envelope, the friction pad being configured to penetrate at least partly into the guide cavity to guide the first of the two elements in translation relative to the second.

[0010] Thanks to such a combination of characteristics, the same friction pad configured for adjusting the resistive force to oppose the relative translational movement between the two elements, is also configured to cooperate in a guide cavity and thus ensure the angular guidance of the inner tube relative to the outer tube during their relative translation in the case of an adjustment. Such a guide cavity therefore makes it possible to guarantee freedom of translation during the adjustment and to constrain the angular position of the tubes relative to each other during this adjustment.

[0011] According to one embodiment, the guide cavity is delimited by a continuous wall of the second of the two elements. Such a cavity can be obtained simply by local deformation of the tubular wall of the tube, for example by stamping or die-casting. Of course, other manufacturing methods can be used to produce such a guide cavity, for example by extrusion or even during the production of the tube, by drawing. Such a characteristic allows improved reinforcement of the second of the two elements in that the wall is structurally continuous, that is to say without discontinuity in the structure which could be formed by a hole. Preferably, the thickness of the wall is continuous so as to further improve the structural strength of the second of the two elements.

[0012] According to one embodiment, the second of the two elements has a perimeter taken in its cross-section around the reference axis, at right angles to the adjustment cavity, equal to the perimeter of its cylindrical envelope.

[0013] According to one embodiment, the guide cavity comprises an orifice opening into the wall of the second of the two elements. Such an opening may be, for example, a groove extending parallel to the reference axis and serving as a guide rail for the friction pad so as to guide it during translation and prevent any relative rotation of the two inner and outer tubes.

[0014] According to one embodiment, the guide cavity supports at least a portion of the clamping surface. In such a configuration, the guide cavity is both configured to guide the friction pad while having surface contact with the friction pad making it possible to ensure resistance opposing the translational movement of the two tubes of the steering column sleeve.

[0015] According to one embodiment, the guide cavity is configured so that, when a torque is applied between the two elements around the reference axis, the second element exerts on the friction pad a force whose resultant preferably has a component orthogonal to the reference axis, for example radial.

[0016] According to one embodiment, the guide cavity has two guide side walls, preferably symmetrical with respect to each other, for example with respect to a plane parallel to or containing the reference axis, the guide side walls being oriented towards the inside of the second of the two elements, the clamping surface being carried by one and / or the other of the guide side walls. The orientation of the guide side walls is such that, in this configuration, a pivoting of the second of the two elements around the reference axis causes the friction pad to slide along one or the other of the guide side walls, depending on the direction of rotation, resulting in a force from said guide side wall on the friction pad, the resultant of which has a component parallel to a clamping axis adjustment system tending to move the friction pad away from the second of the two elements.

[0017] According to one embodiment, the sheath comprises an energy storage means, configured to exert, directly or indirectly, an elastic stress on the friction pad tending to keep the friction pad pressed against the clamping surface. Preferably, this energy storage means works at least partly axially, and is generally oriented along the clamping axis. In this way, the elastic stress generated by an energy storage means makes it possible to absorb part of the resultant of the forces of the guide wall on the friction pad.

[0018] According to one embodiment, the adjustment system comprises an annular body having an outer surface provided with a radial thread extending coaxially to a clamping axis, for example orthogonal or even radial relative to the reference axis, and configured to cooperate with a tapped hole in the first of the two elements, the annular body being configured to apply a predetermined pressure to the friction pad. In such a configuration, the first of these two members comprises a radial interface in the manner of a screw that can be screwed into the first of the two elements, in particular into a tapped hole in the outer tube.

[0019] According to one embodiment, the adjustment system comprises a spring forming an energy storage means, preferably a spring washer, arranged between the annular body and the friction pad. Such a spring washer has a generally conical shape, an axis of symmetry of which is arranged coaxially with the clamping axis in the assembled position of use.

[0020] According to one embodiment, the sheath comprises a plurality, preferably two, adjustment systems, the friction pads of each of the adjustment systems being configured, for example, to penetrate at least partly into the same guide cavity to guide the first of the two elements in translation. It may also be preferred, depending on the uses, for all or part of the friction pads to penetrate into different guide cavities.

[0021] According to one embodiment, the second of the two elements comprises the inner tube, the first of the two elements comprising the outer tube of the sheath. brief description of the figures

[0022] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate: [fig.l]: a perspective view of a part of a steering column according to one embodiment; [fig.2]: another perspective view of part of a steering column according to this embodiment; [fig.3]: a detail of [fig.2]; [fig.4A]: a sectional view of a friction pad of an adjustment system in a guide cavity according to a first embodiment; [fig.4B]: a detail of [fig.4A]; [fig.4C]: a simplified view of [fig.4B]; [fig.5]: a sectional view of a friction pad of an adjustment system in a guide cavity according to a second embodiment; [fig.6]: a sectional view of a friction pad of an adjustment system in a guide cavity according to this second embodiment, in a stressed position; [fig.7]: a sectional view of a friction pad of an adjustment system in a guide cavity according to a third embodiment; [fig.8]: a sectional view of a friction pad of an adjustment system in a guide cavity according to a fourth embodiment; [fig.9]: a sectional view of a friction pad of an adjustment system in a guide cavity according to a fifth embodiment; [fig.10]: a sectional view of a first friction pad of an adjustment system in a guide cavity according to a sixth embodiment; [fig.l 1]: a sectional view of a second friction pad of an adjustment system in a guide cavity according to this sixth embodiment.

[0023] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED description of an embodiment

[0024] Figures 1 and 2 illustrate perspective views of a portion of a steering column 103 of a motor vehicle such as a car, provided with a sleeve 103. The sleeve 103 of the steering column is of the type comprising a telescopic system with two tubes 101, 102, an outer tube 101 and an inner tube 102 configured to translate inside the outer tube 101 along a reference axis X. The steering column comprises an axis, such as a steering shaft 105, guided in rotation in the sleeve 103, generally by plain or rolling bearings 106. The inner 102 and outer 101 tubes of the sheath 103 are axially traversed by the steering shaft having a distal end 105B projecting relative to the inner tube 102 and configured to be connected directly or indirectly to a steering wheel (not shown). Another end 105A of the steering shaft, projecting relative to the outer tube 101, has an interface such as a universal joint serving as an angle transmission for rotating a pinion meshing with a steering rack (not shown). The depth adjustment of the steering wheel for a user is enabled in particular by the translation of the inner tube 102 relative to the outer tube 101 of the sheath 103.

[0025] To drive and guide this relative translation of the tubes 101, 102 relative to each other, a drive mechanism is provided with a drive screw 200 of the relative axial position of the tubes 101, 102 extending along an axis X' parallel to the reference axis X and connected to the outer tube 101 fixed during axial adjustment. In this way, the drive screw 200 is integral in translation with the outer tube 101 by means of the guide bearings, for example two, which are configured to guide the drive screw 200 in rotation about its axis X'. The drive screw 200 meshes with a nut 201 secured to the inner tube 102 so that a rotation of the drive screw 200 around its axis X' causes a displacement of the nut 201 in translation relative to the drive screw 200 parallel to the reference axis X, and therefore an axial displacement of the inner tube 102 relative to the outer tube 101.

[0026] To mask the operating play and ensure minimum stiffness of the connection of the two tubes 101, 102 relative to each other, the sheath 103 of the steering column is provided with at least one friction pad 20, in particular two in this illustrated embodiment, supported by the outer tube 101 and configured to come into contact and bear against a clamping surface 30 of the inner tube 102. The system is configured so that a predetermined pressure of the friction pad 20 carried by the outer tube 101 is applied against the clamping surface 30 of the inner tube 102. Such pressure of the pad 20 aims to increase a resisting force to oppose the relative translational movement between these two elements constituted by the outer 101 and inner 102 tubes.

[0027] In the embodiment illustrated in Figures 1, 2 and 3, the sleeve 103 of the steering column comprises two adjustment systems 10. The invention proposes to integrate into at least one of the friction pads 20, at least one function of guiding the outer tube 101 in translation relative to the inner tube 102.

[0028] Figures 4A, 4B and 4C illustrate a first embodiment of the invention. The inner tube 102 has an outer surface inscribed in a cylindrical envelope E, and the outer tube 101 has a cylindrical inner surface. The inner surface of the outer tube 101 delimits a tubular interior space inside which the inner tube 102 penetrates and cooperates so that this cooperation forms a sliding pivot connection between the two tubes 101, 102.

[0029] The second 102 of the two elements 101, 102, i.e. the inner tube 102, is provided with a guide cavity 40 forming a hollow space 41 relative to the cylindrical casing E (see [fig.4C]). This guide cavity 40 extends axially relative to the reference axis X. The guide cavity 40 is carried by the inner tube 102 and open, substantially radially outwardly, precisely towards the outer tube 101 when it is located on a portion covered by said outer tube 101. At least one of the two friction pads 20 is configured to penetrate at least partially into the guide cavity 40 to guide the outer tube 101 in translation relative to the inner tube 102, the friction pad 20 forming an obstacle to the relative rotation of the tubes 101, 102 relative to each other.The sliding pivot connection made by the two inner tubes 102 and outer tubes 101 is thus constrained into a sliding connection thanks to the friction pads 20 so that the inner tube 102 translates inside the outer tube 101 along the reference axis X.

[0030] The guide cavity 40 is axially delimited by its two opposite ends 40'. In practice, a translation mechanism of the two tubes is controlled by the drive screw 200, itself controlled in rotation directly or indirectly by a geared motor 202. The translation mechanism is further configured so that the translation does not reach its two extremes 40', in particular by the placement, on the sheath, of stops to limit the translation of the two tubes 101, 102 relative to each other in one direction and / or both directions of translation. In the event of a vehicle collision, in particular exceptional translation of the two tubes 101, 102 in the direction of retraction of the inner tube 102 into the outer tube 101 beyond a nominal adjustment stroke, for example between 20 and 30 mm, the end 40' or the associated stop of the guide cavity 40 can be configured to participate in absorbing the shock.Advantageously, the guide cavity 40 allows translational guidance of the tubes 101, 102 during collision, following a collision travel extending beyond the nominal adjustment travel, for example over 80 or 100 mm so that the guide system does not interfere with the collision absorption system. In practice, the guide cavity 40 extends axially, on either side of the clamping surface 30 against which the friction pad(s) 20 bears, over a distance corresponding to the useful travel of the inner tube 102 in the outer tube 101.

[0031] The guide cavity 40 extends laterally along a width configured so that said guide cavity extends over an angular sector of a circumference of the inner tube 102 at least equal to 20 degrees, preferably 30 degrees and less than or equal to 60 degrees, preferably less than or equal to 45 degrees.

[0032] In this embodiment, the guide cavity 40 is delimited by a continuous wall 42 of the second 102 of the two elements 101, 102. In particular, in each section at right angles to the guide cavity 40, the periphery of the wall delimiting the tube around the reference axis X is closed and continuous, preferably in one piece. Likewise, the wall along this periphery is preferably configured so as to have a substantially constant thickness. The wall 42 delimiting the guide cavity 40 forms a flat relative to the cylindrical envelope E of the inner tube 102. The wall 42 has a flat outer surface 42' against which the associated friction pad 20 comes into contact and bears, creating a resistive force opposing a relative translational movement between the two elements 101, 102.The guide cavity 40 supports the clamping surface 30, said clamping surface 30 constituting, here, a part of the outer surface 42' of the wall 42 delimiting the guide cavity 40. A friction surface 20' of the friction pad 20 provided to rub against the clamping surface 30 has a complementary planar shape so as to maximize the surface contact with the clamping surface 30.

[0033] As illustrated in more detail in [fig.4B], the adjustment system 10 comprises an annular body 123 having an outer surface 121 provided with a thread 122 orthogonal to the reference axis X, in particular radial here, and configured to cooperate with a tapped hole 111 of the outer tube 101. The annular body 123 is configured to apply a predetermined pressure on the friction pad 20 in the manner of a tightening nut.

[0034] The adjustment system further comprises an energy storage means 50, configured to exert, directly or indirectly, an elastic stress on the friction pad 20 tending to keep the friction pad 20 in abutment against the clamping surface 30, despite possible vibrations in dynamic behavior of the vehicle or to press the friction pad against the inner tube 101 during an adjustment. The energy storage means 50 comprises a spring washer 16 arranged between the annular body 123 and the friction pad 20, the spring washer 16 having a substantially conical shape, one base of which is oriented towards the friction pad 20. The spring washer 16 exerts a pressure force as a function of its compression.The spring washer 16 has a stiffness enabling it to generate the force which, depending on the screwing of the annular body 123 into the tapped hole 111 provided for this purpose, guarantees the minimum stiffness of the connection between the two outer tubes 101 and inner tubes 102.

[0035] This support of the spring washer 16 against the friction pad is indirect here given that the adjustment system 10 comprises a flat distribution washer 18, centered on a clamping axis A i0 and interposed between the spring washer 16 and the pad friction pad 20. Such a flat washer 18 has the function of distributing a force from the spring washer 16 over the surface of the friction pad 20, thus making it possible to distribute the pressure forces evenly over the friction pad 20.

[0036] The annular body 123 forming a screw nut, the spring washer 16, the flat washer 18, and the friction pad 20 are aligned along the clamping axis A i0 orthogonal to the reference axis X, and in particular here radial relative to said reference axis X.

[0037] During manufacturing, and once these different components have been put in place in the tapped hole 111, a tightening procedure combining torque and angle makes it possible to obtain the compression of the spring washer 16 to a desired value which determines the force applied to the inner tube 102 by the associated friction pad 20.

[0038] The friction pad 20, in rear contact with the washer 18 and rubbing frontally on the clamping surface 30 of the inner tube 102, is made of thermoplastic material with the possibility of adding a lubricating charge. The friction pad 20 can also be made of a metallic material such as, for example, sintered bronze.

[0039] The guide cavity 40 is configured so that, when a torque is applied between the inner 102 and outer 101 tubes around the reference axis X, the inner tube 102 exerts on the friction pad 20 a force whose resultant has a component R parallel to the clamping axis A i0. Indeed, a rotation of the inner tube 102 causes a pivoting of the guide cavity 40, in particular of the flat outer surface 42' against which the friction pad 20 is supported. This pivoting creates a force on the friction pad 20 whose resultant R is directed in a direction opposite to that of its support and tends to move the friction pad 20 away from the flat surface 30.

[0040] When a torque is applied to the inner tube 102, this tends to cause the friction pad 20 to rise towards the clamping nut 123. This movement is initially prevented by the force exerted by the spring washer 16. This ensures precise guidance of the translation of the inner tube 102 relative to the outer tube 101 during the phases of adjustment of the axial position of the steering wheel, where a relatively low torque is likely to be applied to the inner tube 102.

[0041] When the torque increases, the force of the spring washer 16 is no longer sufficient to prevent the movement and the latter compresses until it comes to a "block" or to the maximum compression stop. This position corresponds to a maximum compression position of the spring washer 16, which then has zero deflection and a generally flat shape. The force is then taken up by the annular body 123 forming a tightening nut. This ensures a recovery of the torque, even of a significant value, for example when force is applied to the steering wheel while an anti-theft device is engaged, the anti-theft device generally comprising a locking bolt blocking its rotation (not illustrated).

[0042] Figures 5 and 6 illustrate sectional views of a friction pad 20 of an adjustment system 10 in a guide cavity 40 according to a second embodiment.

[0043] This embodiment differs essentially from the first embodiment in that the guide cavity 40 is no longer formed by a simple continuous planar wall 42, but by a continuous wall 42 having a V-shaped section. More precisely, the guide cavity 40 has two guide side walls 44, 45 formed together in one piece with the wall of the inner tube 102, the two guide side walls 44, 45 being directed or oriented towards the inside of the inner tube 102 so as to form the guide cavity 40 which has a concave shape.

[0044] The guide cavity 40 supports the clamping surface 30. In fact, the friction pad 20 comprises a friction surface 20' having a substantially complementary shape with a V-shaped profile cooperating in the guide cavity 40. Thus, the convex shape of the friction pad 20 is configured to interface with the concave shape of the guide cavity 40 produced in the inner tube 102.

[0045] The friction pad 20 may have an axis of symmetry of revolution parallel or even coaxial with the clamping axis A i0, taking an inverted conical shape, for example, to cooperate in the V shape and rub against the two guide side walls 44, 45. In another preferred configuration, in particular to maximize the friction surfaces of the surface contact between the friction pad 20 and the guide cavity 40, the friction pad 20 may have two slopes, in particular with a symmetry with respect to a plane parallel to a plane containing the clamping axis A i0, for example in the shape of an inverted prism with a triangular base. The clamping surface 30 is carried by the two guide side walls 44, 45.

[0046] [Fig. 6] illustrates a position of the friction pad 20 when a torque is applied to it by the inner tube 102. Thanks to the slopes arranged at its guide interface, in particular by means of the guide side walls 44, 45 delimiting the concave guide cavity 40, these being V-shaped, the friction pad 20 moves away radially under the effect of the force exerted by the spring washer 16, until it comes into contact with an internal wall of the hole 111 housed in the outer tube. The symmetry of the guide side walls 44, 45 allows a similar torque recovery whether the torque applied is in one direction or the other. The guidance of the inner tube 102 is thus precise and the torque recovery has little or no impact on its precision.Furthermore, this concave shape with inclined side walls, of constant inclination in this embodiment, unlike a flat wall 42, offers better force absorption when a torque is applied to the inner tube 102 and guarantees better precision in guiding the translational movement. Preferably, the inclination of the guide walls is strictly lower. at 90 degrees relative to a straight line tangent to the envelope E, preferably greater than or equal to 30 degrees and preferably less than or equal to 60 degrees. Preferably, the guide cavity 40 is made so that the section of the tube remains constant, or even the thickness. The perimeter of the tube is then equal to the perimeter of a tube of the same perfectly cylindrical diameter, not having such a guide cavity 40, namely equal to the perimeter of its envelope E (see in particular figures 5, 6, 7, 8, 10 and 11).

[0047] [fig.7] illustrates a sectional view of a friction pad 20 of an adjustment system 10 in a guide cavity 40 according to a third embodiment.

[0048] This embodiment differs essentially from the second embodiment in that the guide cavity 40 is not formed by a simple continuous flat wall 42, but by a continuous wall 42 having a V-shaped section, but has a circular arc section. The wall is thus continuous with respect to the wall of the body of the tube, of constant thickness at the guide cavity 40. The wall 42 has a variable inclination, of constant variation, allowing a more gradual absorption of forces than a V-shape. Preferably, the circular arc of the section of the guide cavity 40 has a radius of curvature substantially equal to the radius of the tube which carries it, namely here of the inner tube 102.

[0049] It will be noted that the arcuate section of the wall 42 delimiting the guide cavity may have another shape, for example the shape of an oval arc.

[0050] [fig.8] illustrates a sectional view of a friction pad 20 of an adjustment system 10 in a guide cavity 40 according to a fourth embodiment.

[0051] This embodiment differs essentially from the second embodiment in that the same adjustment system 10 comprises a friction pad 20 provided with two distinct and separate friction surfaces 20', each friction surface 20' being here carried by two friction elements. It will be noted that it is possible to alternatively provide a friction pad in a single part whose shape is configured to have two friction surfaces 20', for example in the form of a pad having a cross-section in the shape of an inverted "U". Each of these two friction surfaces 20' is configured to be in contact and in abutment against the clamping surface 30 supported by the guide cavity 40, in particular in separate contact and in abutment against each of the clamping surfaces 30 carried by the guide side walls 44, 45.The advantage of this embodiment is to mask the play that there may be between the friction pad 20 and the body 101, the two friction elements or half-pads coming to bear on the interior surface of the hole 111.

[0052] Thanks to the guide cavity 40, the two friction elements of the friction pad 20 move apart under the effect of the torque exerted by the inner tube 102 on one of the two elements of the friction pad 20, the force exerted by the friction pad 20 comprising a component parallel to the clamping axis A i0 so that it is taken up by the washer spring 16 and by the annular body 123 forming a nut.

[0053] [Fig.9] illustrates a sectional view of a friction pad 20 of an adjustment system 10 in a guide cavity 40 according to a fifth embodiment.

[0054] This embodiment differs from the previous embodiments in that the guide cavity 40 comprises an orifice 43 opening into the wall of the second 102 of the two elements 101, 102, such a configuration however allowing less better recovery of the torque by the energy storage means 50.

[0055] Here, the guide cavity 40 does not support the clamping surface 30, said clamping surfaces being carried by the side walls 102' bordering the orifice extending axially parallel to the reference axis X like a guide groove. The clamping surface 30 is therefore carried by the edges of the cylindrical body of the inner tube 102.

[0056] In this embodiment, the guide cavity 40 is not configured so that, when a torque is applied between the inner 102 and outer 101 tubes around the reference axis X, the inner tube 102 exerts on the friction pad 20 a force whose resultant has a component R parallel to the clamping axis A i0. However, it will be noted that the edge of these edges may comprise slopes (not illustrated) configured so that when a torque is applied between the two elements 101, 102 around the reference axis 100, the edge of said edges of the inner tube 102 exerts such a force on the friction pad 20.

[0057] The friction pad 20 is composed of a single piece and has a central projection 21 separating two wings carrying lateral friction surfaces 20', each of these friction surfaces 20' coming into surface contact and bearing against one and the other of the two external surfaces of the cylindrical body of the inner tube 102 bordering the orifice 43, on either side of the central projection 21.

[0058] Figures 10 and 11 illustrate sectional views of a first friction pad 20A and a second friction pad 20B of an adjustment system 10 in a guide cavity 40 according to a sixth embodiment.

[0059] The sheath 103 of the steering column comprises two adjustment systems 10, the friction pads 20 of each of the adjustment systems 10 being configured to penetrate at least partly into the same guide cavity to guide in translation the first 101 of the two elements 101, 102.

[0060] The guide cavity 40 is here similar to that of the second and fourth embodiments and has a V-shaped section. However, here, the first friction pad 20A of a first adjustment system 10 ensures the guidance and the torque recovery in a given direction, clockwise (see [fig. 10]), while the second friction pad 20B of a second adjustment system 10 ensures the guidance and the torque recovery in the other direction, counterclockwise (see [fig. 11]). This allows the clearance between the friction pad 20 and the outer tube 101 to be hidden.

[0061] Unlike the previous embodiments, in this sixth embodiment, the clamping axes A i0 of the adjustment systems 10 are not radial, but they are orthogonal to the reference axis X and parallel to a plane containing the radial axis with a predetermined center distance e in a transverse plane, the center distance e being substantially equal here to the radius of the corresponding tapped hole 111.

[0062] Naturally, the invention is described in the above by way of example. It is understood that those skilled in the art are able to carry out different variant embodiments of the invention without departing from the scope of the invention.

[0063] For example, the clamping axis A i0 may be oriented differently than orthogonally to the reference axis. In this case, the clamping axis is at least carried by an axis not parallel to the reference axis, either by a non-coplanar axis or by a secant axis.

[0064] To increase the precision of the guidance, the friction part can be extensible, that is to say it can extend laterally or radially relative to the clamping axis, or comprise a plurality of friction elements, for example more than two.

[0065] In the case where the steering column sleeve comprises a plurality of adjustment systems, it is understood that one of the adjustment systems may comprise a conventional friction pad in contact and bearing against a cylindrical zone of the inner tube while a second, or more, adjustment system comprises a friction pad configured to ensure the guidance and the recovery of the torque.

[0066] Furthermore, it is understood that the adjustment system may comprise a different structure without altering the function of the friction pad. For example, the adjustment systems may be electrically controlled.

[0067] The guide cavity may also comprise a combination of a space delimited by a wall 42 of the second of the two elements, whether the surface(s) are flat or inclined, and a through hole. The wall 42 is in this case discontinuous.

[0068] Furthermore, it may possibly be envisaged in another embodiment an inverted configuration of the friction pad and the guide cavity. In this configuration, the second of the two elements comprises the outer tube and the second of the two elements comprises the inner tube of the sheath, the friction pad then being supported by the inner tube. The guide cavity would then be formed by a hollow space relative to a cylindrical envelope in which is inscribed the inner surface of the outer tube inside which the inner tube is housed. The guide cavity is then carried by the outer tube and open, substantially radially inwards, precisely towards the inner tube when it is located on a portion crossed by said inner tube.

[0069] The adjustment systems may have a different structure with regard to its adjustment. In particular, a control mechanism may be integrated to control the adjustment system, the adjustment mechanism comprising, for example, a cam bearing directly or indirectly on a support to generate a variation in pressure of the friction pad relative to the clamping surface parallel to the clamping axis fixed relative to the first of the two elements, so as to vary the pressure force of the friction pad against the clamping surface of the second of the two elements, between: a use position, in which a predetermined use pressure of the friction pad is applied against the clamping surface of the second of the two elements; and, an adjustment position, in which an adjustment pressure lower than the use pressure is applied by the friction pad against the clamping surface of the second of the two elements.

Claims

Claims

1. Steering column sleeve (103) comprising two elements constituted by an outer tube (101) and an inner tube (102) movable in translation relative to each other along a reference axis (X), and at least one adjustment system (10) of a resistive force opposing a relative translational movement between the two elements (101, 102), the pressure mechanism comprising: - at least one friction pad (20), supported by a first (101) of the two elements (101, 102); - a clamping surface (30) secured to a second (102) of the two elements (101, 102), the friction pad (20) being configured to be in contact and in abutment against the clamping surface (30), the second (102) of the two elements (101, 102) having a surface inscribed in a cylindrical envelope (E), the sheath of the steering column being characterized in that the second (102) of the two elements (101,102) comprises a guide cavity (40) extending axially relative to the reference axis (X) and being delimited by a continuous wall (42) of the second (102) of the two elements (101, 102), the guide cavity (40) forming a hollow space (41) relative to the cylindrical envelope (E) and having a concave shape, the friction pad (20) being configured to penetrate at least partly into the guide cavity (40) to guide in translation the first (101) of the two elements (101, 102) relative to the second (102), the guide cavity (40) supporting at least part of the clamping surface (30).,

2. Steering column sleeve (103) according to claim 1, characterized in that, in each section at right angles to the guide cavity (40), a periphery of the wall delimiting the tube of the second (102) of the two elements (101, 102) around the reference axis (X) is closed and continuous, preferably in one piece.

3. Steering column sleeve (103) according to claim 2, characterized in that the wall along the periphery of the wall delimiting the tube of the second (102) of the two elements (101, 102) around the reference axis (X) is configured so as to have a thickness sens- possibly constant.

4. Steering column sleeve (103) according to any one of the preceding claims, characterized in that the second (102) of the two elements (101, 102) has a perimeter taken in its cross section around the reference axis, at right angles to the adjustment cavity (40), equal to the perimeter of its cylindrical envelope (E).

5. Steering column sleeve (103) according to any one of the preceding claims, characterized in that the guide cavity (40) is configured so that when a torque is applied between the two elements (101, 102) around the reference axis (100), the second (102) of the two elements (101, 102) exerts on the friction pad (20) a force whose resultant preferably has a component (R) orthogonal to the reference axis (X).

6. Steering column sleeve (103) according to claim 5, characterized in that the guide cavity (40) has two guide side walls (44, 45), preferably symmetrical to each other, the guide side walls (44, 45) being oriented towards the inside of the second (102) of the two elements (101, 102), the clamping surface (30) being carried by one and / or the other of the guide side walls (44, 45).

7. Steering column sleeve (103) according to any one of the preceding claims, characterized in that it comprises an energy storage means (50), configured to exert, directly or indirectly, an elastic stress on the friction pad (20) tending to keep the friction pad (20) in abutment against the clamping surface (30).

8. Steering column sleeve (103) according to any one of the preceding claims, characterized in that the adjustment system (10) comprises an annular body (123) having an outer surface (121) provided with a radial thread (122) extending coaxially to a clamping axis (Ai0), for example orthogonal or even radial relative to the reference axis (X), and configured to cooperate with a tapped hole (111) of the first (101) of the two elements (101, 102), the annular body being configured to apply a predetermined pressure to the friction pad (20).

9. Steering column sleeve (103) according to claims 7 and 8, characterized in that the adjustment system (10) comprises a spring (16) forming an energy storage means (50), preferably a spring washer, arranged between the annular body and the friction pad.

10. Steering column sleeve (103) according to any one of the preceding claims, characterized in that it comprises a plurality, preferably two, adjustment systems (10), the friction pads (20) of each of the adjustment systems (10) being configured to penetrate at least partly into the same guide cavity to guide in translation the first (101) of the two elements (101, 102).

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