WO2018083412A1

WO2018083412A1 - Increased friction steering column clamping system

Info

Publication number: WO2018083412A1
Application number: PCT/FR2017/052992
Authority: WO
Inventors: Mickael Sauquet; Alain Carrer; Rémi BERNARD
Original assignee: Roberts Bosch Automotive Steering Vendôme
Priority date: 2016-11-07
Filing date: 2017-10-31
Publication date: 2018-05-11
Also published as: CN109923021B; FR3058379B1; CN109923021A; HUP1900216A1; FR3058379A1

Abstract

The present invention relates to a steering column (1) of a vehicle comprising: a supporting base (2) intended for being attached to the chassis and including two clamping walls (20); a steering member intended for being connected to a steering wheel, hingedly mounted on the supporting base and arranged between the clamping walls; a clamping mechanism for locking the column, so that each clamping wall has an inner contact area in contact with an outer contact area of the steering member; in this column, the inner contact areas (28) and/or the outer contact areas have increased roughness compared with the rest of the faces (26) that support them.

Description

FRICTION STEERING COLLAR CLAMPING SYSTEM

INCREASED

The present invention relates to an adjustable vehicle steering column, more particularly to a steering column adjustable in rotation with respect to a support base fixed to the chassis of the vehicle.

The steering column according to the invention is intended in particular but not exclusively for a motor vehicle.

The steering columns transmit the rotation of the steering wheel to the wheels to change their orientation, for example in the following order: the steering wheel, the steering column, the intermediate axis, the rack and finally the wheels.

The current steering columns allow adjustment in depth and / or height of the steering wheel.

In a conventional manner, a steering column comprises: a steering member intended to be connected to a vehicle steering wheel,

a support base of this steering member with respect to the chassis of the vehicle,

- Clamping means arranged to lock the steering member on the support base.

On known steering columns, the height adjustment is made by rotation of the steering member about a horizontal axis mounted on the support base. This is called radial adjustment.

After choosing the position of the steering wheel, the driver actuates the locking system which fixes this position by clamping, in particular by means of a clamping screw, clamping walls of the support base around the steering member.

Vertical slip resistance is often critical, even in situations other than a vehicle accident. Indeed, in the context of a current use it may happen that a user exerts a vertical pressure on the steering wheel. For example, he can hang the latter by removing a jacket or hook to get into the vehicle.

Now there is very often a clearance between the clamping means and the support base and / or the steering member. Therefore, during such a vertical pressure, the steering member will slide slightly, a few tenths of a millimeter relative to the support base, before being actually blocked.

This game may be perceived as a lack of robustness, or even interpreted as a failure of the locking system.

To remedy this, the simplest solution is to obtain a sufficiently high minimum voltage to prevent slippage. However, these friction systems are limited in terms of resistance level of effort. Furthermore, depending on the configuration of the steering column, in particular its length between the clamping screw and the steering wheel, the lever arm is such that the necessary tension may be insufficient in case of attachment.

The technical problem that aims to solve the invention is to find a clamping system of the steering member to feel a stiffness even if hanging from the steering otherwise than increasing the clamping force.

For this purpose, an object of the invention is a steering column comprising:

a support base intended to be fixedly mounted relative to a vehicle chassis and comprising two clamping walls,

- A steering member intended to be connected to a vehicle steering wheel, this steering member being articulated to the support base and arranged between the two clamping walls,

a clamping mechanism arranged in such a way as to allow the clamping walls to be brought closer to one another in a manner to clamp the steering member between the clamping walls, to lock the steering column, so that when the steering column is locked, each clamping wall has on an inner face an internal contact zone in contact with a zone external contact of an outer face of the steering member,

each internal contact zone and / or each external contact zone being a rough contact zone, whose roughness is greater than that of the remainder of the face comprising this rough zone.

In other words :

the surface of each internal contact zone has a roughness greater than that of the remainder of the corresponding inner face of the clamping walls, and / or

the surface of each external contact zone has a roughness greater than that of the rest of the corresponding outer face of the steering member.

This increase in roughness causes an increase in the friction force between the contacting regions of the support base and the steering member. It thus makes it possible to feel a stiffness from the beginning of the attachment of the steering wheel, reducing in particular the risk of feeling a game that can be interpreted as a failure.

Furthermore, this increase in the friction force is achieved independently of the clamping force allowed by the clamping mechanism. The steering column according to the invention is therefore more easily adaptable to different types of steering column design, including with higher steering column lengths.

As it is a surface roughness, there is no play induced by these characteristics, unlike for example blocking mechanisms. Moreover, this makes it possible to limit the number of contact zones and its extent. This improves the overall size, the sound level during the bearing and the cost of the steering column.

The invention may optionally have one or more of the following features:

the clamping mechanism can include:

o a clamping screw, and

o clamping members mounted on the clamping screw and arranged on either side of the support base, the clamping screw successively passing through a first clamping wall, the steering member and a second clamping wall, in such a way that the rotation of the clamping screw in one direction or the other makes it possible to move the clamping members towards each other or to move them away from each other so as to clamp the support base, clamping or thereby loosening the steering member between the clamping walls; it is a simple way to make a tightening to lock or unlock a steering column;

the clamping screw can pass through the clamping walls and the walls of the steering member through through holes, said passage holes, the contact areas being distributed around these through holes, in particular to the edge of these passage holes, on the faces provided with these contact zones; thus the clamping force is transmitted directly to the contact areas, which reinforces the tightening; in addition, the rough contact areas will generate a more effective brake in case of attachment of the steering wheel; the movable element may be a driven cam in longitudinal displacement along the axis of the clamping screw by actuating a counter cam carried by the clamping screw;

each passage hole forms in the thickness of the corresponding clamping wall a peripheral edge, this peripheral edge being for example smooth; this allows easy sliding of parts possibly brought into contact with the peripheral portion, for example the clamping screw;

the cam may comprise sliders arranged inside the passage hole of the first clamping wall so as to slide against the edges of this passage hole; this allows a guide of the cam relative to the support base when adjusting the steering column; these edges may be formed by the smooth peripheral edge of the preceding paragraph;

the surface of each rough contact zone may have asperities distributed over its entire extent and conferring on it its roughness;

these asperities may be irregular in shape; the stiffness of irregular asperities is greater than that obtained with regular asperities;

the asperities can be formed by ablations of material in the corresponding rough contact area; it is a simple and economical form of achievement of asperities, by degradation of a surface;

the asperities can be obtained by sanding and / or blasting; asperities thus have shapes and distributions conferred by these methods of obtaining; they are also easier to achieve; in addition, by using irregular sand grains or broken shots, the surface of the rough zone includes a distribution random unevenness, reinforcing stiffness; asperities achieved by sanding allow a lower realization cost;

the asperities can be formed by projections of a material on the corresponding rough contact area; it is an alternative embodiment of irregular asperities;

the projections may be of tungsten carbide; this can for example be achieved by a method of electric arc projection or plasma;

the asperities can be formed by deformations of the surface of the corresponding rough contact area; these deformations can be made directly in a stamping tool, for example in the stamping tool to form the support base from a sheet metal plate and / or in the stamping tool to form a part the steering member from a sheet metal plate; in these latter cases, a paver with a high roughness, corresponding to the negative of these asperities, can be arranged on the stamping tool,

the support base and the steering member can be arranged in such a way that the internal contact areas move away from the external contact areas when the column is unlocked; this facilitates the adjustment;

- According to the preceding paragraph, the steering member may comprise on each side at least one boss vis-à-vis the inner faces of the clamping walls, the bosses comprising a smooth sliding face arranged to be in contact with these inner faces-ci when the steering column is locked and when unlocked, these contacts being made in an area of the inner faces of the clamping walls other than said internal contact areas; this allows to limit the game when unlocking, while allowing easy sliding of the steering member against the support base, thus reducing the noise caused during adjustment;

the sliding faces may be flat and the areas of the internal faces of the clamping walls in contact with them are planar; this facilitates sliding and further limits the game;

the steering member may comprise gripping walls vis-à-vis the clamping walls, interconnected on one side and free of the other, these gripping walls being connected by an arcuate portion, the bosses being arranged in the arcuate portion and at the edge of the gripping walls, each gripping wall comprising an outer contact area; thus during tightening, the clamping walls bear on these sliding surfaces and deform around them by approaching each other, to come into contact with the gripping walls; it is a simple embodiment of the two preceding paragraphs;

- the management body may include:

a lower body articulated on the support base and comprising the engagement walls and the arcuate portion,

o an upper tube fitted into the lower body in contact with the arcuate portion, the gripping walls extending along the lower tube, at a distance from the latter, and on either side of a longitudinal axis present the steering column;

the distortion of the previous paragraph is thus reinforced; Moreover, the depth adjustment can thus be easily made by sliding the upper tube in the lower body;

alternatively or in addition to bosses on the steering member, the internal faces of the clamping walls may comprise bosses arranged vis-à-vis the outer faces of the steering member, the bosses comprising a smooth sliding face arranged in such a way as to be in contact with these external faces when the steering column is locked and when it is unlocked, the support base and the steering member being arranged in such a way that the internal contact areas away from external contact areas when the column is unlocked; this also limits any play during unlocking, while allowing easy sliding of the steering member against the support base, thus reducing the noise caused during adjustment;

the bosses can be obtained by stamping a sheet metal plate of the steering member, in particular a sheet metal plate forming the arcuate portion and the engagement walls; this allows for example to achieve them in a single operation during the stamping of the sheet metal plate;

the bosses are inserts on the steering member, in particular on the arcuate portion, for example by being clipped therein; this makes it possible to simplify the elements embossing the sheet metal plate, by making these parts separately;

the sliding faces are curved;

the sliding faces are offset radially and outwardly relative to the external contact areas; the bosses may for example be offset radially and outwardly by about 3 tenths of millimeters with respect to the external contact areas; the steering member may be adjustable in rotation about a pivot axis, the passage holes in the clamping walls having slightly curved edges, in particular in curvatures corresponding to an arc of a circle centered on the pivot axis and in a plane perpendicular to this pivot axis.

Other features and advantages of the invention will appear on reading the detailed description of the following nonlimiting examples, for the understanding of which reference will be made to the appended drawings, among which:

Figure 1 is a perspective view of an example of a steering column according to the invention, seen from the left side;

Figure 2 is a perspective view of the steering column of Figure 1 as seen from the right;

Figure 3 is an exploded view of Figure 1;

Figure 4 is a front perspective view of a lower body of the steering member of the steering column of the preceding figures;

- Figures 5 and 6 are side views of the lower body of Figure 4, respectively the right side and the left side;

Figures 7 and 8 are vertical longitudinal sections of the support base of the steering column of Figures 1 to 3, respectively on the right side and the left side.

Figures 1 to 3 illustrate a steering column 1 for a motor vehicle according to the invention, incorporating a cap 2 forming a support base for a steering member 3. Indeed, this cap 2 is intended to be fixed to the frame of the vehicle, when assembling the latter. The steering member 3 comprises a tube, said upper tube 6, connected to a flying end 7, the latter being intended to be connected to the steering wheel (not shown) of the vehicle. The steering wheel tip 7 forms the end of a free steering shaft rotating about an axis of rotation. This rotation makes it possible to transmit the rotations of the steering wheel to the steering mechanisms (not shown) which cause the orientation of the wheels of the vehicle. This axis of rotation is called the steering column axis.

The upper tube 6 is slidably mounted in a lower body 5 along an axis of axial adjustment, coaxial with the steering column axis. The reference A designates in the drawings indifferently these two axes. This sliding allows a first adjustment in depth of the steering wheel, also called axial adjustment.

The lower body 5 is mounted free to rotate about a pivot axis 4, or pivot shaft, carried by the cap 2. This is an embodiment for the articulation of the steering member 3 to the cap 2. This rotation allows a radial adjustment of the wheel around an axis of rotation C. The pivot axis 4 is intended to be horizontal when the steering column 1 is mounted in the vehicle. This radial adjustment is still called height adjustment.

The cap 2 comprises a left clamping wall 20 and a right clamping wall 21. The lower body 5 is arranged between the two clamping walls 20, 21.

A clamping mechanism is arranged to allow the cap 2 and the steering member 3 to be tightened together, and in particular, the cap 2, the lower body 5 and the upper tube 6. This makes it possible to lock the entire column. steering in a fixed position relative to the vehicle frame, and thus maintain in position the steering wheel during use of the vehicle. More particularly, the clamping mechanism is arranged so that when the steering column 1 is locked, the clamping mechanism moves said clamping walls 20, 21 towards one another. Thus, this makes it possible to grip the steering member 3, here its lower body 5, between the clamping walls 20, 21.

Once the steering column 1 is locked, each clamping wall 20, 21 has on an internal face an internal contact zone in contact with an external contact zone of an outer face of the steering member 3, here of the body lower 5, as will be detailed later.

According to the invention, each internal contact zone and / or each external contact zone is a rough contact zone. That is, the roughness of a given rough contact area is greater than that of the remainder of the face comprising this rough area.

This makes it possible to confer an initial stiffness between the steering member 3 and the cap 2. Thus, if the steering wheel is hooked up by the driver, exerting a vertical force, this will prevent the feeling of play.

In the example shown, only the contact areas of the inner faces of the cap 2 are rough, and will hereinafter referred to as rough contact areas.

The clamping mechanism is also arranged to be able to loosen, the cap 2 and the steering member 3, and in particular, the cap 2, the lower body 5 and the upper tube 6 then being tightened together. It is then possible to make the axial and / or radial adjustments of the steering wheel.

In the exemplary embodiment illustrated, the clamping mechanism comprises:

a clamping screw 9, a clamping lever 8 mounted at a first end of the clamping screw 9,

- Clamping members mounted on the clamping screw 9. The clamping members comprise in this example a movable member 10, here formed by a cam 10 mounted on the side of the outer face 24 of the left clamp wall 20. They comprise also a stop 12, in particular a needle stop, and a clamping nut 13, mounted at a second end of the clamping screw 9 and at the side of the external face 25 of the right clamping wall 21.

As can be seen in FIG. 3, the clamping screw 9 comprises a longitudinal axis corresponding to the direction of clamping of the movable element 10 against the cap 2 and therefore of the latter and of the steering member 3. longitudinal axis is hereinafter called clamping axis B.

The abutment 12 having a larger diameter than the through hole 23 of the clamping screw through the right clamping wall 21, it forms a stop relative to a translational movement of the clamping screw 9 along the axis tightening B.

Here the cam 10 comprises a central hole through which the clamping screw 9 passes, so that the cam 10 can slide along the clamping screw 9 and through this central hole.

The cam 10 may comprise ramps 81 cooperating with cam paths (not shown) fixed relative to the clamping screw, in particular carried by the lever 8. Thus, according to the rotation of the lever 8 in locking or unlocking, the paths of cam drive the cam 10 in displacement along the clamping screw 9, respectively towards or away from the left clamping wall 20.

An elastic element 11 can be arranged between the cam 10 and the left clamp wall 20 to facilitate the spacing of the cam 10 of this wall during unlocking. A locking member 11 with teeth may also be arranged on the left clamping wall 20 to allow locking of the lower body 5 in the event of a collision. These teeth engrain with unrepresented teeth of the cam 10 and located here on the face opposite to the ramps 81.

In this example, the locking element and the elastic element are a single piece, here a sheet metal plate. Nevertheless, this is not mandatory, the elastic member could be a spring and the locking member could be another tooth system (s).

In the illustrated example, the locking element 11 is fixed on the left clamping wall 20, at the bottom at the lower edge of this wall 20, and at the top at a fixing arch 14 arranged that the outer face 24 of this wall 20. In particular, the bottom and the top of the blocking element 11 can be clipped and / or inserted on this wall 20.

The clamping screw 9 is arranged through passage holes 52, 53 of the lower body 5, in which it is free to rotate about the clamping axis B. Thus, this clamping screw 9 is carried by the lower body 5 These passage holes are more visible in Figures 4 to 6.

The lower body 5 comprises an arcuate portion 60 connecting two sidewalls, arranged on either side and in contact with the upper tube 6. Each of these sidewalls is pierced to form one of the through holes 52, 53 of the screw. tightening 9.

Here these flanks each comprise a gripping wall 50, 51. The latter each have an outer face 56, 57.

Each side also comprises a transfer member 54, 55 of clamping force, fixed on an inner face of the corresponding engagement wall 50, 51, namely a face opposite to its outer face 56, 57. Each member of transfer 54, 55 is in direct contact with the upper tube 6. In this example, each transfer member 54, 55 defines a bottom wall, which with the arcuate portion 60 defines a housing 63, extending longitudinally along the longitudinal axis A of the steering column 1. The upper tube 6 is mounted telescopically movable in this housing 63, thus allowing the axial adjustment of the column 1.

According to the invention, and as illustrated in FIG. 4, the arcuate portion 60 and the gripping walls 50, 51 may be formed by a single sheet metal plate of generally "U" section.

The through holes 52, 53 formed here through the transfer members 54, 55 and the engagement walls 50, 51 have a height slightly greater than the diameter of the clamping screw 9 passing therethrough.

This thus creates a height clearance on either side of the clamping screw 9. This clearance can be from 1 to 8 tenths of a millimeter. It is this game that in the absence of rough area could lead to a displacement without initial stiffness in case of attachment of the steering wheel.

To overcome a feeling of failure due to such a game, the cap 2 thus includes internal rough areas 29, 28 arranged on the internal faces 27, 26 of its clamping walls 21, 20. These rough areas 29, 28 are respectively illustrated in FIGS. 7 and 8.

Each of the clamping walls 20, 21 comprises a through hole 22, 23 of the clamping screw 9.

According to the invention and as in this example, these through holes 22, 23 formed in the clamping walls 20, 21 are arranged in such a way that the clamping screw 9 can be rotated relative to the cap 2 and solidarily to the lower body 5.

In particular, these through holes 22, 23 may have an arcuate shape, with edges corresponding to centered circles. on the pivot axis 4. This is the case in the illustrated example, where these passage holes form arcuate oblong holes 22, 23, and are hereinafter referred to as left windows 22 and right 23. The clamping screw 9 can then move along these windows 22, 23, including maintaining the orientation of the clamping axis B, including a horizontal orientation.

The left and right outer faces 56 of the lower body 5 are respectively facing the inner faces 26, 27 of the left and right clamping walls 21.

It is around windows 22, 23 that each inner face

26, 27 comprises an internal contact zone 28, 29 which comes into contact with an external contact zone 58, 59 of the lower body 5. The internal contact zones 28, 29 are symbolized in FIGS. filled with points.

Similarly, the external contact areas 58, 59 are arranged around the through holes 52, 53 formed in the engagement walls 50, 51. They are symbolized by a shaded area in FIGS. 5 and 6.

In particular, in the illustrated example, these contact zones go up to the edge of the through holes 22, 23, 52, 53. In other words, these through holes 22, 23, 52, 53 are formed in the zones contact 28, 29, 58, 59.

In the example shown, the internal contact area 28, 29 of each clamping wall 20, 21 is a rough contact area.

Asperities of irregular shapes are distributed randomly over the entire surface of each of these rough contact areas 28, 29.

According to the invention, as in the example illustrated, the asperities may for example be arranged so that the rough areas have a profile having: an arithmetic average roughness Ra of between 5 and 15 micrometers (μm), namely that the average arithmetic deviation with respect to the average line of the surface of the rough zone is in this example between 5 and 15 microns (pm ), and

a maximum roughness Rz of between 50 and 90 μm, namely that the difference between the deepest and the highest relief roughness is between 50 and 90 μm.

In this example, these asperities were formed by degradation of the surface of the inner faces 26, 27 of the clamping walls 20, 21, here by sanding non-round grains, preferably of irregular shapes.

These examples of sand are purely illustrative and other types of sand could be used.

During sanding, the parts outside the corresponding internal contact area are masked.

Moreover, the windows 22, 23 are made in the thickness of the sheet forming the clamping walls 20, 21. Consequently, they are delimited by a peripheral wafer 30, formed in the thickness of these clamping walls 20, 21.

In this illustrated mode, at least the peripheral portion 30 of the window 22 of the left clamping wall 20 is smooth. This can be obtained in particular by masking this peripheral portion 30 during sanding.

The peripheral edge of the window 23 of the right clamping wall 21 can also be smooth.

In the illustrated example, the engagement walls 50, 51 are offset outwardly relative to the arcuate portion 60. However, the arcuate portion 60 comprises on each side of the lower body 5 bosses 61, 62. The latter extend radially relative to the remainder of the arcuate portion 60 and each have a flat face, called sliding face. In FIGS. 5 and 6, these sliding faces are presented with hatches that are narrower than those of the external contact zones 58, 59. It should be noted that alternatively, these sliding faces could be curved, the faces facing each other. these sliding faces, here the inner faces of the clamping walls 20, 21, being planar.

These sliding faces are offset radially with respect to the external contact zones 58, 59.

The bosses 61, 62 may, for example, be offset radially and outwards by 3 tenths of millimeters with respect to the external contact zones 59, 58.

When the steering column 1 is assembled, these bosses 62, 61 are here in contact with the internal faces 26, 27, clamp faces, above the rough areas 28, 29, so in a smooth zone, called sliding 65, 66. These sliding zones are illustrated by a shaded area in FIGS. 7 and 8.

The operation of the steering column 1 according to the illustrated example will now be detailed.

The locking operation of the lever 8 pushes the cam 10 coming into direct or indirect contact, as here by intermediate support on the sheet metal plate forming the blocking element 11. The cam 10 thus bears against this left clamping wall 20. In doing so, the clamping screw 9 transmits a voltage to the stop 12. At least a portion of this stopper 12 and the cam 10 are thereby brought closer to each other.

Thus, the cam 10 and the abutment 12 clamp the cap 2, thus bringing the clamping walls 20, 21 closer to the cap 2, which thus themselves take the lower body 5 in a vice, thereby bringing the gripping walls closer together. 50, 51. The clamping force is thus transmitted via the contact zones 28, 29, 58, 59, as close as possible to the clamping screw 9.

The clamping force is then transferred to the transfer members 54, 55 in the direction of the arcuate portion 60, with these transfer members 54, 55 being arranged to approach the arcuate portion 60 as the engagement walls 50, 51 move toward each other. The upper tube 6 is thus caught in a vice between these transfer members 54, 55 and the arcuate portion 60.

The steering member 3 is thus locked in a given position, both radially and axially.

During this clamping, the clamping walls 20, 21 bear on the sliding faces of the bosses 62, 61 and come close to each other by deformation, thus ensuring contact between the surfaces 28, 29, 58 and 59.

The bosses 62, 61 may be obtained by stamping the sheet metal plate forming the arcuate portion 60 and the engagement walls 50, 51.

Alternatively, the bosses 62, 61 may be inserts on the arcuate portion 60, for example by being clipped.

According to the invention, at least one boss 61, 62 is arranged on each side of the steering member 3, here of the lower body 5. There is therefore at least one boss to the left of the axis A of the column and a right boss of this axis A. For example, the bosses 61, 62 may, as here, be two in number per side of the steering member 3, here the lower body 5.

When unlocking the lever 8, the cam paths no longer exert pressure on the cam 10, the stress on the clamping walls 20, 21 and the flanks of the lower body 5 decreases, and the cam 10 away from the left clamp wall 20. As a result, the upper tube 6, the lower body 5 and the cap 2 are no longer clamped together. It is then possible to adjust the flywheel axially along the axis A of the column 1 or radially around the axis of rotation C.

The cap 2 and the steering member 3 are arranged so that the rough contact areas 28, 29 deviate from the external contact areas 58, 59, upon unlocking.

According to the invention, as here, the sliding faces of the bosses 61, 62 are arranged to remain in contact with said sliding zones 65, 66 when the steering column 1 is unlocked. This maintains a smooth sliding contact with less noise compared to contact with rough surfaces. The setting is less noisy.

In this example, this is achieved by the radial offset of the sliding faces with respect to the rough contact areas 28, 29.

The clamping movement exerts sufficient force to hold the steering member 3 in position during normal use of the vehicle. For example, this clamping keeps the flywheel blocked despite the application of a vertical force at the steering wheel from 200 to 1000 Newtons.

Despite this tightening, as previously seen in the locked position, the steering column 1 has a slight clearance between the clamping screw 9 and the upper and lower edges of the through holes 52, 53 of the engagement walls 50, 51. However, thanks the roughness of the rough contact areas 28, 29, there is an increase in the coefficient of friction between the lower body 5 and the clamping walls 20, 21, to slow the vertical movement in case of attachment of the steering wheel. This avoids a feeling of defectiveness of the steering column 1. According to the invention, the coefficient of friction of the surfaces of the rough contact areas 28, 29 can be between 0.2 and 0.35, the surfaces outside these rough contact areas 28, 29 having a coefficient of friction included between 0, 1 and 0, 15.

Note that the face of the cam 10 opposite that carrying the ramps 81 may carry projections extending from this opposite face and forming sliders, not visible in these figures, in particular on either side of the central hole of the cam 10 in which the clamping screw 9 passes.

These sliders are arranged with a width allowing them to slide against the peripheral portion 30 of the window 22 of the left clamping wall 20, thus guiding the cam 10 in position during the axial adjustment. This sliding is facilitated because the peripheral edge 30 is smooth.

Claims

1. Steering column (1) comprising:

a support base (2) intended to be fixedly mounted relative to a vehicle chassis and having two clamping walls (20, 21),

- a steering member (3) intended to be connected to a vehicle steering wheel, said steering member being articulated to said support base and arranged between the two clamping walls,

a clamping mechanism arranged so as to allow the clamping walls to be brought closer to each other so as to clamp the steering member between the clamping walls, so as to lock the steering column, so that when the steering column is locked, each clamping wall has on an inner face (26, 27) an inner contact area (28, 29) in contact with an outer contact area (58, 59) of an outer face (56); , 57) of the steering member, the steering column being characterized in that each internal contact zone and / or each external contact zone is a rough contact zone, whose roughness is greater than that of the rest of the face including this rough area.

Steering column according to claim 1, characterized in that the clamping mechanism comprises:

a clamping screw (9), and

- clamping members (10, 13) mounted on the clamping screw and arranged on either side of the support base (2), the clamping screw (9) passing successively through a first clamping wall (20). , the steering member (3) and a second clamping wall (21), so that the rotation of the clamping screw in one direction or the other makes it possible to bring together or to move the clamping members away from each other so as to clamp the support base, thereby tightening or loosening the steering member between the clamping walls.

3. Steering column according to claim 2, characterized in that the clamping screw passes through the clamping walls (20, 21) and the walls of the steering member (3) through through holes, said passage holes (22, 23, 52, 53), the contact zones (28, 29, 58, 59) being distributed around these through holes on the faces (26, 27, 56, 57) provided with these contact zones.

4. Steering column according to claim 3, characterized in that each through hole (22, 23, 52, 53) forms in the thickness of the corresponding clamping wall (20, 21) a smooth peripheral edge (30). .

5. Steering column according to any one of the preceding claims, characterized in that the surface of each rough contact zone (28, 29) has asperities distributed over its entire extent and conferring its roughness, these asperities being of shapes. irregular.

6. Steering column according to claim 5, characterized in that the asperities are formed by ablations of material in the corresponding rough contact area (28, 29).

7. Steering column according to claim 6, characterized in that the asperities are obtained by sandblasting and / or shot blasting.

8. Steering column according to claim 5, characterized in that the asperities are formed by projections of a material on the corresponding rough contact area (28, 29).

9. Steering column according to claim 8, characterized in that the projections are tungsten carbide.

Steering column according to one of the preceding claims, characterized in that the support base (2) and the steering element (3) are arranged in such a way that the internal contact areas (28, 29 ) deviate from the external contact areas (58, 59) when the column is unlocked, and in that the steering member comprises on each side at least one boss (62, 61) facing the faces internal members (26, 27) of the clamping walls (20, 21), the bosses comprising a smooth sliding face arranged to be in contact with these inner faces (26, 27) when the steering column is locked and when unlatched, these contacts being made in an area of the internal faces of the clamping walls other than the internal contact areas (28, 29).

11. Steering column according to claim 10, characterized in that the sliding faces are flat and the areas of the inner faces (26, 27) of the clamping walls (20, 21) in contact with them are planar.

Steering column according to claim 10 or 11, characterized in that the steering member (3) comprises engagement walls (50, 51) facing the clamping walls (20, 21), interconnected on one side and free of the other, these gripping walls being connected by an arcuate portion (62), the bosses (62, 61) being arranged in the arcuate portion and at the edge of the gripping walls, each gripping wall comprising an outer contact area (28, 29).

Steering column according to claim 12, characterized in that the steering member (3) comprises: a lower body (5) articulated on the support base and comprising the engagement walls (50, 51) and the arcuate portion (60),

- an upper tube (6) fitted in the lower body in contact with the arcuate portion (62), the gripping walls extending along the lower tube, at a distance therefrom, and on either side of a longitudinal axis (A) that presents the steering column.

Steering column according to one of Claims 10 to 13, characterized in that the bosses

(62, 61) are obtained by stamping a sheet metal plate of the steering member (3).

15. Steering column according to claim 14 when taken in combination with claim 12 or claim 13, characterized in that the bosses (62, 61) are obtained by stamping a sheet metal plate forming the arcuate portion (60 ) and the engagement walls (50, 51).

16. Steering column according to any one of claims 10 to 13, characterized in that the bosses (62, 61) are inserts on the steering member (3).

17. Steering column according to claim 16 when taken in combination with claim 12 or claim 13, characterized in that the bosses (61, 62) are inserts on the arcuate portion (60).

18. Steering column according to any one of claims 10 to 17, characterized in that the sliding faces are curved.

19. Steering column according to any one of claims 10 to 18, characterized in that the sliding faces are offset radially and outwardly relative to the outer contact areas (58, 59).

20. Steering column according to any one of the preceding claims, characterized in that the inner faces of the clamping walls comprise bosses arranged vis-à-vis the outer faces of the steering member, the bosses comprising a face smoothly slidably arranged to contact said outer faces when the steering column is locked and when it is unlocked, the support base and the steering member being arranged so that the internal contacts deviate from external contact areas when the column is unlocked.