Steering column assembly having telescopic arm and electromechanical actuator for actuating arm

Abstract

Steering column assembly (1) for a vehicle comprising a steering wheel, the steering column assembly comprising:-a frame (2) arranged for being fixedly mounted on a vehicle structure; -a telescopic arm (3) extending in a longitudinal direction (AX) carried by the frame, the longitudinal extent of which determines the position of the steering wheel, the arm (3) comprising at least two translationally displaceable segments (14, 16); and-an electromechanical actuator (25) for longitudinally displacing said segments (14, 16) between an extended position and a retracted position of said arm (3), the electromechanical actuator comprising:-an electric motor (26); -a motion converter (31) converting the rotation provided by said electric motor (26) into translation of the first segment (14); and-a transmission system (32) driving the second segment (16) in translation in response to the translation of the first segment.

Description

Technical Field

[0001] The present invention relates to the general field of motor vehicles and, more particularly, to a steering column assembly of a vehicle steering system. Background Art

[0002] The steering column is one of the components that make up the vehicle's steering system. The steering column is present on all vehicles and allows the transmission between the steering wheel and the wheels.

[0003] As is known, a steering column comprises a fixed bracket rigidly mounted on a superstructure element of the vehicle, such as the chassis, and an arm which adjusts the position of the steering wheel by extending the fixed bracket into the vehicle compartment towards the seat on which the driver sits.

[0004] In practice, the space between the steering wheel and the seat should be large enough to allow the driver to sit comfortably in the seat without having to twist his limbs for this purpose. This characteristic is often in conflict with the driving posture, in which the measured space between the steering wheel and the seat is rather limited in order to ensure that the driver can grip the steering wheel comfortably and safely.

[0005] To solve this problem, it has been proposed to make the arm telescopic, that is, to give it the ability to retract and extend. The arm then takes the form of a stepped structure, comprising a plurality of segments that are nested and can move in translation relative to each other.

[0006] With this solution, the steering wheel becomes displaceable between a retracted position, in which it is far enough from the seat so as not to interfere with the driver's seating, and an extended position, in which the space between the seat and the steering wheel is reduced. Note that this solution is particularly interesting for fitting on autonomous vehicles, where the retracted position of the arm can be adopted for comfort purposes in vehicle driving situations where manual trajectory control is not required.

[0007] To manipulate the forward movement of the telescopic arm, electromechanical actuation has been proposed, allowing the steering wheel to be displaced without driver intervention, as opposed to mechanical actuation which requires manual operation by the driver each time it is used.

[0008] A conventional electromechanical actuation system comprises an electromechanical actuator for displacing one segment relative to the other. Although such a system seems to be effective for an arm consisting of only two segments associated, of which only one is displaced along the second, such a system imposes a limit on the maximum stroke of the arm. In fact, unless the length of the segments of the telescopic arm is increased and therefore the length of the steering column is increased, which is not always possible given the space available in the vehicle, the stroke of the arm is limited both structurally and functionally.

[0009] In order to meet a given stroke length of the arm without causing an increase in the overall length of the steering column, it has been proposed to increase the number of segments displaced relative to each other and to provide multiple actuators, each dedicated to displacing one segment relative to another. However, such a multi-stage actuator design presents certain difficulties, such as:

[0010] - the complexity of distributing the control commands to the actuators increases in order to assign the correct instructions to the actuators, and

[0011] - Increased electrical consumption and noise generation, either due to the need to increase the displacement speed of each segment in order to meet a given actuation time in the case of a cascade actuation of the segments, or due to the simultaneous actuation of the segments (which requires that each actuator be supplied with the energy required to perform its function at the same moment).

[0012] The object of the present invention is to propose an electromechanical actuation structure of an arm of a steering column which at least partially avoids the above-mentioned disadvantages of the known solutions. Summary of the invention

[0013] To this end, the subject of the invention is a steering column assembly for a steering system of a vehicle, such as an automobile, comprising:

[0014] - a frame configured to be fixedly mounted on the structure of the vehicle;

[0015] a telescopic arm extending in the longitudinal direction, carried by the frame and having a longitudinal extent allowing the position of the vehicle steering wheel to be adjusted, the arm comprising at least two segments at least partially nested in succession, a first segment being displaceable in longitudinal translation relative to the frame carrying it, and a second segment being displaceable in longitudinal translation relative to the first segment by being at least partially nested in it,

[0016] - an electromechanical actuator for displacing the segment in translation in the longitudinal direction between an extended position of the arm, in which the arm has a maximum measured longitudinal extent, and a retracted position of the arm, in which the arm has a minimum measured longitudinal extent, the electromechanical actuator comprising:

[0017] - an electric motor for driving the rotation;

[0018] a motion converter that converts the rotation provided by the electric motor into a translation of the first segment relative to the frame, the motion converter comprising an active element that is fixed in translation relative to the frame and a driven element that translates integrally with the first segment in the longitudinal direction; and

[0019] - A transmission system that drives the second segment in translation in response to the translation of the first segment.

[0020] The invention also relates to a steering column assembly as defined above, wherein a transmission system drives the second segment to translate in response to the translation of the first segment, the transmission system comprising:

[0021] a threaded rod having a longitudinal axis, which translates integrally with the second segment and which is at the same time freely rotatable about its axis, and

[0022] - a first nut and a second nut carried by the threaded rod, each of the first nut and the second nut comprising a thread for cooperating with the threaded rod, the first nut being blocked from rotating about the threaded rod and being fixed to the frame, the second nut being blocked from rotating about the threaded rod and being fixed to the second segment.

[0023] The invention also relates to a steering column assembly as defined above, wherein a transmission system drives the second segment to translate in response to the translation of the first segment, the transmission system comprising:

[0024] - two wheels, separated from each other in the longitudinal direction and coupled in rotation by a belt or a chain, these wheels forming a pulley and each wheel being movable in rotation about a respective axis, the wheels being movable in translation integrally with the first segment;

[0025] - a first attachment element, which connects the belt to the frame; and

[0026] - A second attachment element connecting the belt to the second segment.

[0027] The invention also relates to a steering column assembly as defined above, wherein the transmission system drives the second segment in translation in response to the translation of the first segment, the transmission system comprising two consecutive transmission stages, wherein:

[0028] - one transmission stage is dedicated to displacing the attachment element attached to the frame;

[0029] - another transmission stage dedicated to displacing the attachment element attached to the second segment;

[0030] Each level includes:

[0031] - two pulleys which are movable in rotation about their respective axes of rotation, which pulleys are movable in translation integrally with the first segment; and

[0032] - a belt or chain which rotatably connects the corresponding pulleys;

[0033] And among them:

[0034] - the pulley of one stage is rotationally coupled to the pulley of another stage;

[0035] - The attachment elements attached to the frame are fixed to a belt or chain of one level, while the attachment elements attached to the second segment are fixed to a belt or chain of another level.

[0036] The invention also relates to a steering column assembly as defined above, wherein:

[0037] - the electric motor is fixed to the frame;

[0038] - the active element of the motion converter is a screw extending in the longitudinal direction, the threaded rod being driven in rotation by an electric motor and being translationally immobile relative to the frame;

[0039] The driven element of the motion converter is a nut carried by a screw, which is blocked from rotating and translates integrally with the first segment.

[0040] The invention also relates to a steering column assembly as defined above, wherein:

[0041] - an electric motor is fixed to the first segment;

[0042] - the active element of the motion converter is a nut which is blocked from rotating and fixed to the frame;

[0043] The driven element of the motion converter is a screw extending in the longitudinal direction and carrying a nut, the screw being driven in rotation by an electric motor and translating integrally with the first segment.

[0044] The invention also relates to a steering column assembly as defined above, wherein:

[0045] - the electric motor is fixed to the frame;

[0046] - the active element of the motion converter is a pinion with an axis perpendicular to the longitudinal direction, which is driven in rotation about its axis by an electric motor,

[0047] The driven element is a rack that translates integrally with the first segment, the pinion meshing with the rack.

[0048] The invention also relates to a steering column assembly as defined above, wherein:

[0049] - an electric motor is fixed to the first segment;

[0050] -The active element of the motion converter is a rack fixed to the frame;

[0051] The driven element is a pinion with an axis perpendicular to the longitudinal direction, which is driven in rotation by the electric motor and meshes with the rack.

[0052] The invention also relates to a steering column assembly as defined above, wherein:

[0053] - the electric motor is fixed to the frame;

[0054] The active element of the motion converter is a wheel with a longitudinal axis, which is defined by:

[0055] - an outer wall with teeth that allow the wheel to be driven in rotation by an electric motor;

[0056] - an inner wall including threads;

[0057] The driven element of the motion converter is a screw that is tightened / loosened along the inner wall of the wheel and that translates integrally with the first segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features and advantages of the present invention will become apparent from reading the following detailed description, for which reference should be made to the accompanying drawings, in which:

[0059] Figure 1 is a perspective view of a steering column assembly according to one embodiment of the present invention, the steering column assembly comprising a frame, a telescopic arm carried by the frame, and an electromechanical actuator for extending / retracting the telescopic arm.

[0060] Figure 2 Shown from different angles Figure 1 A steering column assembly with a portion of the frame covered to reveal the electromechanical actuator.

[0061] Figure 3 yes Figure 1 Cross-sectional view of a steering column assembly.

[0062] Figure 4 is a schematic diagram of a steering column assembly according to the present invention, wherein the electromechanical actuator for extending / retracting the telescopic arm includes a transmission system according to an alternative embodiment.

[0063] Figure 5 is a schematic diagram of a steering column assembly according to the present invention, wherein the electromechanical actuator for extending / retracting the telescopic arm includes a transmission system according to another alternative embodiment.

[0064] Figure 6 is a partial schematic diagram of a steering column assembly according to the present invention, wherein the electromechanical actuator for extending / retracting the telescopic arm comprises a motion converter according to an alternative embodiment.

[0065] Figure 7 is a partial schematic diagram of a steering column assembly according to the present invention, wherein the electromechanical actuator for extending / retracting the telescopic arm comprises a motion converter according to another alternative embodiment.

[0066] Figure 8is a schematic diagram of a steering column assembly according to the present invention, wherein the electromechanical actuator for extending / retracting the telescopic arm includes a transmission system according to yet another alternative embodiment. DETAILED DESCRIPTION

[0067] In the following description, the same, similar or like elements will be denoted by the same reference numerals.

[0068] refer to Figures 1 to 3 , shows a steering column assembly 1 for a vehicle steering system according to one embodiment of the invention. The assembly 1 comprises a frame 2 for fixing to an element of the body structure of the vehicle and an arm 3 carried by the frame 2. The arm 3 extends along a longitudinal direction marked by an axis AX.

[0069] The frame 2 is in the form of a structure defining a recess 4 in which the arm 3 extends at least partially. The frame 2 comprises a base 6 shaped so as to allow it to be rigidly fixed to the dashboard, chassis or any other structural element of the vehicle. To this end, the base 6 notably comprises fixing holes referenced 7. The frame 2 also comprises a housing 8 fixed to the base 6. The housing 8 is in the form of an assembly between a bracket 9 and a cover 11. The bracket 9 is in the general shape of a channel with a longitudinal section having a U-shaped profile. The cover 11 is mounted on the bracket 9 so as to close the U-shaped profile. The recess 4 is jointly defined by the inner surfaces of the bracket 9 and the cover 11.

[0070] The arm 3 surrounds a steering shaft 13 having a longitudinal direction, which is arranged to carry a vehicle steering wheel (not shown) in a rigidly connected manner. More specifically, the steering shaft 13 comprises a free end 15 which protrudes longitudinally from the arm 3 to receive the vehicle steering wheel by fitting.

[0071] In the example shown in the figures, the free end 15 has a hexagonal profile in longitudinal section. However, it should be noted that any other type of shape can be considered to correspond to the negative image of the indentation formed on the steering wheel and the free end 15 engages in this negative image. For example, the free end 15 can include external splines that cooperate with external splines formed at the corresponding indentation of the steering wheel.

[0072] In particular, in the context of the present invention, the arm 3 is telescopic in nature, having the ability to be extended / retracted relative to the frame 2 .

[0073] To this end, it comprises a first segment 14 and a second segment 16 which is nested in the first segment 14 and can be displaced along the first segment 14. Figure 3It can be seen in particular that the first segment 14 comprises a through hole 17, whose axis coincides with the axis AX, and the second segment 16 is slidably mounted in the through hole 17. In the example shown, the hole 17 is cylindrical, and its axis of revolution coincides with the axis AX, but the present invention is not limited to this shape. In practice, the hole 17 may have another shape, such as a prismatic shape, without departing from the scope of the present invention.

[0074] The second section 16 is longitudinally displaceable between a retracted position and an extended position along the bore 17. The retracted and extended positions of the second section 16 are defined such that the second section 16 is received in the bore 17 to a greater extent in the retracted position than in the extended position.

[0075] The first segment 14 is carried by the frame 2. These two elements are shaped so as to allow their relative displacement along the longitudinal direction, which in practice corresponds to a displacement of the first segment 14 relative to the frame 2 which is fixed once mounted in the vehicle.

[0076] The longitudinal displacement of the first segment 14 is limited between a retracted position in which the first segment 14 extends completely in the recess 4 , or at least a large portion of the first segment 14 extends in the recess 4 , and an extended position in which the first segment 14 protrudes longitudinally from the recess 4 .

[0077] In addition, the steering shaft 13 is also essentially retractable along its extension in the arm 3. The steering shaft 13 is in particular connected in translation with the arm 3, so that the extension or retraction of the arm respectively brings about the extension or retraction of the steering shaft 13. Assuming that the steering shaft 13 carries the steering wheel and is displaced in translation integrally with the arm 3, the extended state of the arm 3 makes it possible to adjust the position of the steering wheel in the vehicle cabin. In practice, the arm 3 acts like a muscle: its actuation leads to a change in the longitudinal extent of the steering shaft 13 and therefore to a displacement of the steering wheel integral with the steering shaft 13.

[0078] from Figure 2 It can be seen in particular that the first segment 14 is guided to translate along the recess 4 by two longitudinally extending slide grooves 19. The slide grooves 19 are arranged transversely on both sides of the first segment 14 along an axis AY perpendicular to the axis AX. Each of them is formed by a pair of grooves that jointly restrict the bearing ball 20. Specifically, each slide groove 19 is formed by a first groove (not shown) formed on the inner surface of the bracket 9 and a groove 21 formed by the first segment 14 facing the first groove. The bearing ball 20 forms an interface between the frame 2 and the first segment 14.

[0079] It will be appreciated that the longitudinal displacement of the arm segments 14 and 16 determines the longitudinal extent of the arm 3 and, more generally, the longitudinal extent of the steering column assembly 1. In general, the longitudinal extent of the arm 3 is adjustable between an arm retracted state and an arm extended state, these positions being adjusted by the extended / retracted state of the two segments 14, 16 constituting the arm 3. In practice, the extended state of the arm 3 corresponds to a situation in which the first and second segments 14, 16 are each in an extended position, as opposed to a situation in which the first and second segments 14, 16 are each in a retracted position (which marks the retracted state of the arm 3).

[0080] Considering a steering column assembly 1 installed in a vehicle, i.e., a frame 2 is fixed and an arm 3 extends from the frame 2 toward the driver's seat, then:

[0081] - the extension of the telescopic arm 3 corresponds to a translation of the first and second segments 14 , 16 in the direction marked S1 , which causes a displacement of the steering wheel carried by the steering shaft 13 towards the driver's seat; and necessarily

[0082] The retraction of the arm 3 corresponds to a translation of the first and second segments 14 , 16 in a direction opposite to S1 , which causes the steering wheel to move away from the driver's seat.

[0083] from Figure 3 It can be seen that the steering shaft 13 is advantageously formed by the association of two sections 22 and 23, wherein the first section 22 is connected in translation to the second section 16 and comprises a free end constituting the free end 15 of the steering shaft 13. These sections 22 and 23 are nested in one another, extend coaxially and are centered on the longitudinal axis AX. They are coupled together in rotation by a form fit and can slide relative to one another in the longitudinal direction in order to be able to follow the extension or retraction of the arm 3. Figure 3 In the example shown, the rotational coupling of the segments 22 , 23 is ensured by splines protruding from radially facing segment surfaces.

[0084] The basic idea of ​​the invention is to provide a solution that allows a combined displacement of the first and second segments 14, 16 by the same energy source. In this respect, the steering column assembly 1 according to the invention comprises an electromechanical actuator 25 for extending / retracting the arm 3.

[0085] The electromechanical actuator 25 comprises an electric motor 26 which drives the translation of the first section 14 and the second section 16 of the telescopic arm 3 via a drive mechanism. The drive mechanism comprises two modules that work together:

[0086] a motion converter 31 which converts the rotation provided by the electric motor 26 into a translation of the first segment relative to the frame 2 , and

[0087] A transmission system 32 which drives the second segment 16 in translation in response to the translation of the first segment 14 by the motion converter.

[0088] exist Figures 1 to 3 In the example shown in FIG. 2 , the motion converter 31 is composed of a rack 33 and a pinion 34 meshing with the rack 33 .

[0089] The pinion 34 is mounted so as to be able to pivot about a transversely oriented axis and is fixed to the frame 2. This pinion 34 is driven in rotation by the electric motor 26, which is mounted in a housing 36, which is fastened to the bracket 9 of the frame 2 by screws 37. More specifically, the rotation at the motor output is transmitted indirectly to the pinion 34 via a reducer (not shown) housed in the housing 36. This reducer ensures a reduction in the rotation speed measured at the output of the electric motor 26, which together with the electric motor 26 forms a reducer-motor unit. However, the invention is by no means limited to this particular arrangement and allows the pinion 34 to be driven directly by the electric motor 26.

[0090] The toothed rack 33 extends longitudinally and comprises teeth oriented vertically along an axis AZ orthogonal to the longitudinally oriented axis AX and the transversely oriented axis AY. Figure 2 As can be seen in particular in the figure, the rack 33 is rigidly fixed to the first segment 14 by means of a fixing element referenced 38. It is transversely aligned with the pinion 34, thus allowing them to mesh.

[0091] In operation, ie upon extension / retraction movement of the arm 3 , the rotation of the pinion 34 , which is prevented from translating relative to the frame 2 , causes the rack 33 to be displaced longitudinally, thereby taking the first segment 14 with it as it moves.

[0092] In practice, within the motion converter 31 , the pinion 34 resembles a so-called “active” element, since it acts on the rack to displace it under the action of the electric motor 26 , the rack constituting a “driven” element, the displacement of which corresponds to the translation of the first section 14 of the telescopic arm 3 .

[0093] Regarding the transmission system 32, according to Figures 1 to 3 The embodiment shown comprises a threaded rod 41 mounted on the first segment 14 and extending longitudinally. More specifically, the threaded rod 41 extends along a rod axis vertically offset from the axis AX and parallel to the longitudinally oriented axis. The axis AX coincides with the axis of revolution of the hole 17 of the first segment.

[0094] The threaded rod 41 translates integrally with the first segment 14 and at the same time is free to rotate about its axis. For this purpose, the first segment 14 comprises two bearings 42, 43, at each of which the threaded rod 41 is ensured to be blocked from translation while maintaining the freedom of rotation along its axis.

[0095] The transmission system 32 also includes two nuts 46 and 47, which are carried by the threaded rod 41 and each of which has a thread that cooperates with the thread of the threaded rod 41. The two nuts are identified as follows:

[0096] - a first nut 46 fixedly connected to the frame 2, and

[0097] A second nut 47 fixedly connected to the second segment 16 .

[0098] exist Figure 3 In the example of the second nut 47, the second segment 16 is attached by a deformable coupling 48, which is arranged to deform in the event of an impact in the event of a vehicle collision. More specifically, the coupling 48 is attached to the second nut 47 by riveting and to the second segment 16 by welding. As for the first nut 46, it is attached to the frame 2 by a bolt marked 49. It should be noted that the attachment of the first and second nuts to the frame 2 and the second segment 16, respectively, is not limited to the arrangement in the figure. For example, the second nut 47 can be attached directly to the second segment 16, i.e. without the deformable coupling 48 as an interface.

[0099] In operation, the first segment 14, in its longitudinal displacement caused by the motion converter 31, carries with it the threaded rod 41, which is mounted on the first segment 14. Since once the first nut 46 is fixed to the frame 2, and the first segment 14 rotates integrally with the frame 2 (relative displacement in the longitudinal direction is only possible through the sliding coupling 19), the longitudinal displacement of the threaded rod 41 necessarily causes the threaded rod 41 to rotate about its axis.

[0100] Furthermore, if the extension axis of the threaded rod 41 does not coincide with the axis of revolution of the second segment, a rotation of the second nut 47 is not possible. In the case of a rotation of the threaded rod 41 , this necessarily results in a displacement of the second nut 47 along the threaded rod 41 .

[0101] The kinematics of the operation of the transmission system 32 and, more specifically, the free / blocked states of translation / rotation of the first and second nuts 46, 47 have been explained based on a specific arrangement of the threaded rod 41 that does not allow these nuts to rotate. It should be noted that the invention is not limited to this arrangement of the threaded rod 41, but allows different arrangements, as long as three conditions are met:

[0102] The first nut 46 translates integrally with the frame 2 and is prevented from rotating about the axis of the threaded rod 41;

[0103] - the second nut 47 translates integrally with the second segment 16; and

[0104] The threaded rod 41 carrying the first nut 46 and the second nut 47 translates integrally with the first segment 14 .

[0105] As a non-limiting example, the provision nuts 46 , 47 may be prevented from rotating along the threaded rod 41 by specific dedicated prevention members without departing from the scope of the present invention.

[0106] In general, the pinion 34 of the motion converter 31 is rotated by the electric motor 26 and drives the first segment 14 in translation by cooperating with the rack 33 of the motion converter 31. This translation of the first segment 14 is reflected by the transmission system 32 in an equally direct translation of the second segment 16.

[0107] It should be understood that within the scope of the present invention, the threaded rod 41 and the nuts 46, 47 have threads oriented so that the displacement of the first segment 14 from its retracted position to its extended position in the S1 direction necessarily causes the second segment to be displaced also in the S1 direction. It follows that the translation of the first segment 14 in the direction opposite to the S1 direction imposed by the electric motor 26 is reflected in the translation of the second segment 16 also in the direction opposite to the S1 direction.

[0108] It should be noted that the present invention is not limited to the fact that the translation speed of the second segment 16 is the same as the translation speed of the first segment 14, even if they are displaced simultaneously. In fact, it may be advantageous to provide a displacement speed difference between the two segments 14, 16, in particular if they have different stroke lengths between their respective extended and retracted positions.

[0109] Based on reference Figures 1 to 3 The displacement speed difference between the first and second segments of the electromechanical actuator 25 can be achieved by the thread difference of each element of the transmission system 32. More specifically, the threaded rod 41 can be formed so that the pitch of the threaded portion thereof cooperating with the first nut 46 is different from the pitch of the other threaded portion thereof cooperating with the second nut 47.

[0110] The steering column assembly 1 is not limited to the described arrangement of the electromechanical actuator 25, since it comprises a motion converter 31 and a transmission system 32, each of which maintains its Figures 1 to 3 The functions described in the illustrated embodiment.

[0111] For example, the motion converter 31 is not limited to an arrangement for which the pinion 34 constitutes the active element and the rack 33 corresponds to the driven element. The opposite arrangement can also be envisaged without departing from the scope of the invention. In this case, this involves making the electric motor 26 fixed relative to the first segment 14 and having the arrangement of the pinion 34 and the rack 33 reversed, i.e. having the transverse axis of rotation of the pinion 34 fixed relative to the first segment 14 and having the rack 33 mounted on the frame 2.

[0112] The present invention is not limited to Figures 1 to 3 The constituent elements of the electromechanical actuator 25 are described.

[0113] refer to Figure 4 , another architecture of the transmission system 32 is proposed. In this alternative embodiment, the threaded rod 41 and the pair of nuts 46, 47 are replaced by a belt 51, which connects a pair of wheels 52, 53 forming a pulley. These wheels 52, 53 are longitudinally aligned and are integrally translated with the first segment 14, each wheel being rotationally movable about a corresponding transversely oriented axis fixed to the first segment 14. Two attachment elements 56, 57 are each rigidly fixed to a point on a different belt portion, each different belt portion being defined to extend between the wheels 52, 53. It can be discerned that the first attachment element 56 is attached to the frame 2 and the second attachment element 57 is attached to the second segment 16.

[0114] Similar to the assembly formed by the threaded rod 41 and the nut pair 46, 47, this alternative embodiment provides for the second segment 16 to be longitudinally translated in the direction of S1 when the first segment 14 is also longitudinally translated in the direction of S1. Conversely, the longitudinal translation of the first segment 14 in the direction opposite to the direction of S1 produces the longitudinal translation of the second segment 16 also in the direction opposite to the direction of S1.

[0115] Figure 4 The alternative embodiment of the transmission system 32 shown does not allow for differentiation between the displacement speed of the second segment 16 and the displacement speed of the first segment 14. This feature is achieved by Figure 4 An alternative embodiment of the multi-belt type (such as Figure 5 shown) becomes possible.

[0116] This other variant of the transmission system 32 is generally in the form of two successive transmission stages, one dedicated to displacing the attachment element attached to the frame 2 and the other dedicated to displacing the attachment element attached to the second segment 16. Each of these stages includes two pulleys that can be rotated and moved around corresponding transversely oriented axes and translated integrally with the first segment 14, and also includes a belt that rotationally couples these two pulleys. Providing a pulley of one stage to be rotationally coupled with a pulley of another stage ensures that rotation is transmitted between the two stages. In addition, the attachment element attached to the frame is rigidly fixed to one of the two belts, while the attachment element attached to the second segment 16 is rigidly fixed to the other of these belts.

[0117] exist Figure 5 In the example shown, it can be discerned that:

[0118] - a first stage, which is associated by a first wheel 61, a compound gear mechanism 62 and a first belt 63. The compound gear mechanism 62 comprises a gear 62a in the form of a pulley, which is rotationally coupled to the first wheel 61 by a first belt 63. The compound gear mechanism 62 also comprises a pinion 62b, which is concentric with and rigidly connected to the gear 62a and has a smaller diameter than the gear 62a;

[0119] - a second stage, formed by the association of a second wheel 64 in the form of a pulley and a third wheel 66 in the form of a pulley, these wheels being coupled in rotation by a second belt 67;

[0120] a commutator which ensures the rotational coupling of the pinion 62 b forming the output of the first transmission stage to the second wheel 64 forming the input of the second transmission stage. The commutator is advantageously formed by an idler wheel 70 which is rotationally movable about a respective transversely oriented axis and is fixed to the first segment 14, the idler wheel 70 meshing with the pinion 62 b and the second wheel 64;

[0121] - an attachment element 68 which is attached to the frame 2 and the first belt 63;

[0122] An attachment element 69 which is attached to the second segment 16 and to the second belt 67 .

[0123] In this example, the diameter of the first wheel 61 is smaller than the diameter of the gear wheel 62a, each wheel forming a pulley of the first transmission stage, and as a complement, the diameter of the second wheel 64 is smaller than the diameter of the third wheel 66, each wheel forming a pulley of the second transmission stage. It can be understood that this particular arrangement makes the displacement speed of the second belt 67 lower than the displacement speed of the first belt 63. As a result, the longitudinal displacement speed of the second segment 16 is lower than the longitudinal displacement speed of the first segment 14.

[0124] In this alternative embodiment of the transmission system 32, it is advantageous to provide for the pulley axes to be orthogonally offset so that the pulley portion to which the associated attachment element is fixed is located strictly along the axis of the transmission system 32. Figure 5 The axis marked X1 or X2 in FIG. 1 is oriented longitudinally. This feature aims to balance the diameter differences measured between the pulleys so as not to hinder the longitudinal displacement of the segments 14 , 16 of the arm 3 .

[0125] Another solution is to provide attachment elements 68 , 69 with variable geometry in orthogonal directions to compensate for the orthogonal displacement component of the belts 63 , 67 .

[0126] It should be noted that this alternative embodiment is not limited to the dimensioning of the elements. In the example shown, the diameter of the first wheel 61 is smaller than the diameter of the gear 62a, and the diameter of the second wheel 64 is smaller than the diameter of the third wheel 66. As mentioned above, this arrangement makes the longitudinal displacement speed of the second segment 16 lower than the longitudinal displacement speed of the first segment 14.

[0127] However, the present invention is not limited to this specific arrangement. Instead, the longitudinal displacement speed of the second segment 16 can be higher than the longitudinal displacement speed of the first segment 14 by:

[0128] - changing the sign of the diameter difference between the pulley stages; and

[0129] - The properties of the gear 62a-pinion 62b of the compound gear mechanism 62 are replaced by reversing the values ​​of their diameters.

[0130] Finally, it should be noted that based on Figure 4 and Figure 5 The alternative embodiments described are not limited to the use of belts in the strict sense. One or more chains may be used in place of a belt to achieve similar results. Similarly, any type of belt / chain may be used without departing from the scope of the invention, and the morphology (teeth, splines, etc.) may be modified as necessary to ensure a satisfactory connection.

[0131] Reference Figure 6 Turning to FIG. 9 , an alternative embodiment of the motion converter 31 is presented.

[0132] according to Figure 6 The first alternative embodiment shown proposes to use a screw 71-nut 72 assembly instead of Figures 3 to 5 An example rack 33 - pinion 34 assembly.

[0133] The screw 71 extends in the longitudinal direction and is blocked in translation relative to the frame 2 while being movable in rotation about its axis. The screw 71 carries a nut 72 fixed to the first section 14 of the telescopic arm 3 and blocked in rotation relative to the screw 71 .

[0134] The screw 71 is connected to an electric motor 26 which is also fixed to the frame 2 so that rotation of the screw 71 by the electric motor causes displacement of the nut 72 along the screw and thus of the longitudinal displacement of the first segment.

[0135] Here, the screw 71 corresponds to the driving element of the motion converter 31 , and the nut 72 corresponds to the driven element.

[0136] Figure 7 The second variant shown corresponds to Figure 6 The reverse arrangement of the first variant is shown. It is understood that the nut 72 corresponds here to the active element, while the screw 71 corresponds to the driven element of the motion converter 31 .

[0137] at last, Figure 8 A third alternative embodiment of the motion converter 31 is shown, comprising a gear 81 , a screw 82 and a pivot 83 .

[0138] Reference Figure 8 , the gear 81 is defined by an outer wall 81a and an inner wall 82b, wherein:

[0139] - the outer wall 81a has teeth allowing it to be coupled in rotation with the electric motor 26 fixed to the frame 2; and

[0140] - The inner wall 81b comprises a thread.

[0141] The screw 82 extends in the longitudinal direction and engages in the gear 81. More specifically, the screw 82 includes a thread that matches a thread of the inner wall 81b of the gear.

[0142] Furthermore, the screw 82 is pivotally mounted to the first segment 14 by being carried by a pivot 83 fixed to the first segment 14 .

[0143] With this arrangement, rotation of the gear 81 driven by the electric motor 26 causes tightening / loosening of the screw 82, resulting in translational displacement of the first segment.

Claims

1. A steering column assembly (1) for a steering system of a vehicle such as an automobile, the steering column assembly comprising: - a frame (2) configured to be fixedly mounted on the structure of a vehicle; - a telescopic arm (3) extending in a longitudinal direction (AX), said telescopic arm being carried by said frame (2) and having a longitudinal extent allowing the position of the steering wheel of said vehicle to be adjusted, said telescopic arm (3) comprising at least two segments (14, 16) at least partially nested in succession, a first segment (14) being displaceable in longitudinal translation relative to said frame (2) carrying it, and a second segment (16) being displaceable in longitudinal translation relative to said first segment (14) by being at least partially nested in said first segment (14); - an electromechanical actuator (25) for displacing the segments (14, 16) in translation along the longitudinal direction (AX) between an extended position of the arm (3), in which the arm has a maximum measured longitudinal extent, and a retracted position of the arm, in which the arm has a minimum measured longitudinal extent, the electromechanical actuator comprising: - an electric motor (26) for driving the rotation; a motion converter (31) which converts the rotation provided by the electric motor (26) into a translation of the first segment (14) relative to the frame (2), the motion converter (31) comprising an active element which is translationally fixed relative to the frame (2) and a driven element which translates integrally with the first segment (14) in the longitudinal direction; and - a transmission system (32) which drives the second segment (16) in translation in response to the translation of the first segment (14).

2. The steering column assembly (1) according to claim 1, wherein: The transmission system (32) drives the second segment (16) to translate in response to the translation of the first segment (14), and the transmission system (32) includes: a threaded rod (41) having a longitudinal axis (AX), said threaded rod being integral in translation with said second segment (16) and at the same time being freely rotatable about its axis, and - a first nut (46) and a second nut (47) carried by the threaded rod (41), the first and second nuts (46, 47) each comprising a thread for cooperating with the threaded rod (41), the first nut (46) being prevented from rotating about the threaded rod (41) and being fixed to the frame (2), the second nut (47) being prevented from rotating about the threaded rod (41) and being fixed to the second segment (16).

3. The steering column assembly (1) according to claim 1, wherein: The transmission system (32) drives the second segment (16) to translate in response to the translation of the first segment (14), and the transmission system (32) includes: - two wheels (52, 53) separated from one another in the longitudinal direction and coupled in rotation by a belt (51) or a chain, these wheels forming a pulley and each wheel being movable in rotation about a respective axis, said wheels being movable in translation integrally with the first segment (14); - a first attachment element (56) connecting the belt (51) to the frame (2); and - A second attachment element (57) connecting said belt (51) to said second section (16).

4. The steering column assembly (1) according to claim 1, wherein: The transmission system (32) drives the second segment (16) to translate in response to the translation of the first segment (14), and the transmission system (32) includes two consecutive transmission stages, wherein: - a transmission stage dedicated to displacing an attachment element (68) attached to the frame (2); - another transmission stage dedicated to displacing an attachment element (69) attached to said second segment (16); Each level includes: - two pulleys (61, 62a; 64, 66) which are movable in rotation about their respective axes of rotation, said pulleys being movable in translation integrally with said first segment (14); and - a belt (63; 67) or a chain which connects in rotation the corresponding pulleys (61, 62a; 64, 66); And among them: - a pulley (62a, 64) of one stage is rotationally coupled to a pulley of another stage; - The attachment element (68) attached to the frame (2) is fixed to a belt (63) of one level, while the attachment element (69) attached to the second segment (16) is fixed to a belt (67) or chain of another level.

5. The steering column assembly (1) according to any one of claims 1 to 4, wherein: - the electric motor (26) is fixed to the frame (2); - the active element of the motion converter (31) is a screw (71) extending in the longitudinal direction (AX), the threaded rod (71) being driven in rotation by the electric motor (26) and being translationally immobile relative to the frame (2); The driven element of the motion converter (31) is a nut (72) carried by the screw (71), which nut (72) is blocked from rotating and translates integrally with the first segment (14).

6. The steering column assembly (1) according to any one of claims 1 to 4, wherein: - the electric motor (26) is fixed to the first segment (14); - the active element of the motion converter (31) is a nut (72) which is prevented from rotating and fixed to the frame (2); The driven element of the motion converter (31) is a screw extending in the longitudinal direction (AX) and carrying the nut (72), which is driven in rotation by the electric motor and translates integrally with the first segment (14).

7. The steering column assembly (1) according to any one of claims 1 to 4, wherein: - the electric motor (26) is fixed to the frame; the active element of the motion converter (31) is a pinion (34) having an axis perpendicular to the longitudinal direction, the pinion (34) being driven in rotation about its axis by the electric motor (26), The driven element is a rack (33) that translates integrally with the first segment (14), and the pinion (34) meshes with the rack.

8. The steering column assembly (1) according to any one of claims 1 to 4, wherein: - the electric motor (26) is fixed to the first segment (14); - the active element of the motion converter (31) is a rack (33) fixed to the frame (2); The driven element is a pinion (34) having an axis perpendicular to the longitudinal direction (AX), the pinion being driven in rotation by the electric motor (26), the pinion (34) meshing with the rack (33).

9. The steering column assembly (1) according to any one of claims 1 to 3, wherein: - the electric motor (26) is fixed to the frame (2); The active element of the motion converter (31) is a wheel (81) with a longitudinal axis, which is defined by: - an outer wall (81a) having teeth allowing the wheel to be driven in rotation by the electric motor; - an inner wall (81b) comprising a thread; The driven element of the motion converter is a screw (82) that is tightened / loosened along the inner wall (81b) of the wheel (81), the screw (82) translating integrally with the first segment (14).

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