Mechanical rotary coupling with one-sided locking capability

Abstract

The subject of the invention is a mechanical coupling device for selectively rotationally coupling a first shaft with a second shaft. The coupling device comprises the following components: a first rotating mechanism which is determined to be fixedly connected with the first shaft in a rotating manner; -a first rotational mechanism, which is intended for rotationally fixed connection to the first shaft,-a second rotational mechanism, which is intended for rotationally fixed connection to the second shaft,-a rotationally fixed ring, which surrounds the first mechanism and the second mechanism along an overlapping section where the first mechanism and the second mechanism overlap; -a locking unit for the rotation of the first shaft through the second shaft, the locking unit comprising a groove defined by a ring and an elastic element and a rolling body enclosed in the groove; wherein the rolling body is held in a position clamped in the recess in such a way that the rolling body is pressed by an elastic element in the direction of an opening of the recess, the cross-section of the opening being smaller than the corresponding dimension of the rolling body; and wherein the first mechanism has a release section in order to allow rotation of the second shaft by the first shaft, the release section extending relative to the groove opening in order to be adapted to abut against the rolling body in order to disengage the rolling body from its clamped position.

Description

Technical Field

[0001] The present invention relates to the general field of mechanical force transmission and more particularly to a coupling device between a first and a second concentric rotating element, such as shaft ends, which allows the second element to be rotated by the first element and simultaneously locks the rotation of the first element by the second element. Background Art

[0002] The device can be used in a suitable manner to equip an electromechanical actuator for moving the arm of a steering column structure with a reversible motion converter of the lead screw nut type. However, the present invention is not limited to a specific application.

[0003] The steering column is one of the components forming the steering system of a vehicle. The steering column is present in all vehicles and enables the connection between the steering wheel and the wheels.

[0004] As is well known, the steering column includes: a fixed support member rigidly assembled at an upper structural element of the vehicle, such as a frame; and a steering shaft that supports the steering wheel and extends the fixed support member in the interior space of the vehicle towards the seat where the driver is sitting.

[0005] In practice, the space between the steering wheel and the seat must be large enough so that the driver can sit comfortably on the seat without having to twist for this purpose. This particularity often conflicts with the driving position in which the space measured between the steering wheel and the seat is rather limited in order to enable the driver to achieve a comfortable and reliable grip on the steering wheel.

[0006] To solve this problem, it has been proposed that the steering shaft be equipped with a feasible solution for moving in and out as required.

[0007] In this solution, the steering wheel can move between a retracted position and an extended position. In the retracted position, the steering wheel is far enough away from the seat so that the driver is not hindered when sitting down. In the extended position, the seat-steering wheel space is reduced so that a comfortable grip on the steering wheel can be achieved. It should be noted that this solution is particularly interesting for the equipment of autonomous vehicles in which, during the driving state, manual section control is not required and the retracted steering wheel position can be set for comfort purposes.

[0008] To control the feed of the steering shaft, an electromechanical drive has been proposed that can achieve the movement of the steering wheel without the intervention of the driver. Conventionally, an electric motor and a lead screw nut system are used in the electromechanical drive, where the lead screw is rotated to move the nut, and the position of the nut determines the feed of the steering shaft.

[0009] Typically, a lead screw nut system is designed irreversibly in such a way that the nut is allowed to move along the lead screw only in response to rotation of the lead screw caused by an electric motor and thus the spontaneous movement of the nut is prevented. Due to this particularity, it is possible to prevent the steering wheel from being adjusted unexpectedly by the force applied by the driver to the steering wheel, which is not allowed for ensuring vehicle control.

[0010] However, the irreversibility of the lead screw nut system requires limiting the speed at which the nut moves along the lead screw, which corresponds to limiting the speed at which the steering wheel can be adjusted. Summary of the Invention

[0011] In order to meet the comfort requirements of users, the object of the present invention is to propose a solution that enables reliable use of a reversible lead screw nut system, thereby shortening the waiting time associated with setting the steering wheel.

[0012] For this purpose, the present invention relates to a mechanical coupling device for selectively rotationally coupling a first shaft and a second shaft so as to enable the second shaft to be rotated by the first shaft and at the same time lock the rotation of the first shaft by the second shaft, wherein the coupling device comprises the following components:

[0013] - A first rotating mechanism that determines a structural element for rotationally and fixedly connecting to the first shaft or forming the first shaft;

[0014] - A second rotating mechanism that determines a structural element for rotationally and fixedly connecting to the second shaft or forming the second shaft, wherein the second mechanism extends concentrically with the first mechanism along the longitudinal axis;

[0015] - A rotationally fixed ring that radially surrounds the first mechanism and the second mechanism along an overlapping section with respect to the longitudinal axis, where the first mechanism and the second mechanism overlap in the longitudinal direction;

[0016] - A first locking unit for the rotation of the first shaft by the second shaft in a first rotation direction, wherein the first locking unit includes a first groove and a first elastic element and a first rolling body encapsulated in the first groove, wherein:

[0017] -- The first groove extends in the circumferential direction, which is defined as the deflection direction around the longitudinal axis, wherein the first groove is defined between the groove bottom wall formed by the second mechanism and the groove opening, and the first rotation direction is defined as the direction from the groove opening towards the groove bottom;

[0018] -- The first groove extends radially through the track formed by the second mechanism and is defined by the cylindrical inner wall of the ring relative to the track surface, wherein the track is shaped such that the radial extension of the groove decreases as it gets closer to the groove opening in the circumferential direction, so that the rolling element cannot escape from the groove through the groove opening;

[0019] -- The first elastic element is arranged between the bottom wall of the groove and the first rolling element, wherein the first elastic element passively presses the first rolling element away from the bottom wall of the groove under an elastic preloading force so as to press the first rolling element in the direction of the groove opening until the first rolling element is held in a clamping position between the track and the inner wall of the ring;

[0020] Wherein, the first mechanism has a release section to allow the second shaft to rotate along a first rotational direction by the first shaft, wherein the release section extends in the circumferential direction relative to the groove opening so as to be adapted to, when the first mechanism rotates in the first rotational direction opposite to the direction of the preloading force of the first elastic element, abut against the first rolling element and press the first rolling element in the direction of the bottom of the groove, and simultaneously achieve the following torque so as to overcome the preloading force of the first elastic element and disengage the first rolling element from the clamping position.

[0021] The invention further relates to a correspondingly specified mechanical coupling device, which includes a second locking unit for the rotation of the first shaft by the second shaft along a second rotational direction opposite to the first rotational direction, wherein the second locking unit has a second groove defined between the ring and the first mechanism and the second mechanism, and a second elastic element and a second rolling element encapsulated in the second groove, wherein:

[0022] - The second groove extends in the circumferential direction and is defined between the corresponding groove bottom wall formed by the second mechanism and the corresponding groove opening, wherein the second groove is oriented such that the direction from the opening of the second groove towards the bottom wall of the second groove corresponds to the second rotational direction,

[0023] - The second groove extends radially through the track formed by the second mechanism and is defined by the cylindrical inner wall of the ring relative to the track, wherein the track is shaped such that the radial extension of the second groove decreases as it gets closer to the opening of the second groove in the circumferential direction, so that the second rolling element cannot escape from the second groove through the groove opening;

[0024] - The second elastic element is arranged between the bottom wall of the second groove and the second rolling element, wherein the second elastic element passively presses the second rolling element away from the bottom wall of the second groove so as to press the second rolling element in the direction of the opening of the second groove until the second rolling element is held in a clamping position between the track and the inner wall of the ring;

[0025] And wherein, the first mechanism has a second release section to allow the second shaft to rotate about the first axis in a second rotational direction, wherein the second release section extends circumferentially relative to the opening of the second groove so as to be adapted to, when the first mechanism rotates in the second rotational direction opposite to the pre-tensioning direction of the second elastic element, abut against the second rolling element and press the second rolling element in the direction of the bottom wall of the second groove, and simultaneously achieve the following torque so as to overcome the pre-tensioning force of the second elastic element and disengage the second rolling element from the clamping position.

[0026] The invention furthermore relates to a correspondingly provided mechanical coupling device, wherein, when the rolling element is released from the clamping position by the release section, the rotation of the second shaft about the first axis in the rotational direction locked by the corresponding locking unit is ensured by the first bearing surface of the first mechanism that abuts against the bearing surface of the second mechanism, wherein the first bearing surface and the second bearing surface can overlap each other circumferentially.

[0027] The invention furthermore relates to a correspondingly provided mechanical coupling device, wherein the rotation of the second shaft about the first axis in the rotational direction locked by the corresponding locking unit is ensured by the rolling element and the corresponding elastic element, and the rolling element and the corresponding elastic element form a contact interface between the release section of the first mechanism and the bottom wall of the groove of the locking unit.

[0028] The invention furthermore relates to a steering column assembly for a vehicle, for example a motor vehicle, having the following components:

[0029] - A steering column body, which is arranged for fixedly mounting on the vehicle structure;

[0030] - An arm, which is carried by the steering column body and extends longitudinally therein, wherein the arm at least partially fits into the steering column body and can be displaced translationally along the longitudinal direction with respect to the steering column body;

[0031] - An electromechanical actuator for causing the arm to move translationally along the longitudinal direction, wherein the electronic actuator comprises the following components:

[0032] -- An electric motor for performing rotary drive;

[0033] -- A motion converter of the ball screw type, which converts the rotation provided by the electric motor into the displacement of the arm, wherein the motion converter comprises: a screw, which is translationally fixed with respect to the steering column body; and a nut, which is rotationally fixed and is translationally fixedly connected to the arm along the longitudinal direction;

[0034] -- A correspondingly provided mechanical rotational coupling device for rotationally coupling the screw to a drive shaft rotatably driven at the output end of the electric motor.

[0035] The invention furthermore relates to a correspondingly designed steering column structural component, wherein the mechanical rotation coupling device is an integral component of the drive mechanism, which integral component is arranged in a housing fastened to the steering column body, and the rotation provided by the electric motor is transmitted to the screw via this integral component, wherein the drive mechanism includes a drive shaft which is driven by the electric motor, wherein the first mechanism has a pinion which extends beyond the overlapping section, and wherein the pinion has a tooth section which interacts with the tooth section of the drive shaft.

[0036] The invention furthermore relates to a correspondingly designed steering column structural component, wherein the ring is formed by the housing.

[0037] The invention furthermore relates to a correspondingly designed steering column structural component, wherein the ring is mounted on the housing.

[0038] The invention furthermore relates to a correspondingly designed steering column structural component, wherein one or more rolling elements are rollers.

[0039] The invention furthermore relates to a correspondingly designed steering column structural component, wherein one or more elastic elements are formed by metal strips. Description of the Drawings

[0040] Further features and advantages of the invention become apparent upon reading the following detailed description of the specification, for the understanding of which reference is made to the drawings. Among them:

[0041] Figure 1 A perspective view of a steering column structural component according to an embodiment of the invention is shown, which steering column structural component includes a bracket, an arm displaceable relative to the bracket, and an electromechanical actuator for moving the arm;

[0042] Figure 2 Shown from Figure 1 a detailed view of the drive mechanism motor unit of the electromechanical actuator;

[0043] Figure 3A Shown from Figure 2 a first exploded view of the components of the drive mechanism motor, which particularly shows the mechanical coupling device 38;

[0044] Figure 3B From a perspective different from that of Figure 3A shown from Figure 2 a second exploded view of the components of the drive mechanism motor;

[0045] Figure 4 Along the torque plane A-A from Figure 1 a cross-sectional view of the overlapping section of the mechanical coupling device according to the invention is shown;

[0046] Figure 5 shows a detailed view from Figure 4 ;

[0047] Figure 6A shows a cross-sectional view of a mechanically coupled device corresponding to the mechanically coupled device from Figure 4 and shows the rotational locking dynamics;

[0048] Figure 6B shows a cross-sectional view of a mechanically coupled device corresponding to the mechanically coupled device from Figure 4 and shows the rotational coupling dynamics. DETAILED DESCRIPTION

[0049] In the following description, identical, similar or analogous elements are provided with the same reference numerals.

[0050] Reference is made to Figure 1 which shows a steering column structural assembly 10 for a steering system of a vehicle. The structural assembly 10 includes: a bracket 12 which defines a location for rigid fastening at an upper structural element of the vehicle, such as at a steering shaft; a steering column body 14 carried by the bracket 12; and an arm 16 carried by the steering column body 14. The arm 16 surrounds a steering shaft 18 which is arranged to carry a steering wheel (not shown) of the vehicle.

[0051] The steering shaft 18 extends along an AX axis oriented in a longitudinal direction. The steering shaft 18 extends along the arm 16 which likewise has a longitudinal extension and is arranged for a rotationally rigid coupling with the steering wheel. The steering shaft 18 in particular has a free end 20 which projects beyond the arm 16 in the longitudinal direction in order to receive the steering wheel of the vehicle by pressing.

[0052] In the example from Figure 1 , the free end 20 has a generally circular profile in a longitudinal cross-section and defines a recess which is arranged to receive a projection which forms a pin constructed at a corresponding recess in the steering wheel. It should be noted, however, that any different type of shape can be provided in order to correspond to the negative structure of the recess constructed at the steering wheel, into which the free end 20 engages. The free end 20 can thus for example have an outer groove which co-operates with an inner groove constructed at the corresponding recess in the steering wheel in order to ensure a rotational coupling.

[0053] In the context of the present invention, the steering column structural assembly 10 is arranged to enable the longitudinal position of the steering wheel in the passenger compartment of the vehicle equipped with it to be set.

[0054] For this purpose, the arm 16 is mounted at the steering column body 14 and has longitudinal mobility there. Specifically, the arm 16 and the steering column body 14 are designed such that they allow relative movement in the longitudinal direction, which in practice corresponds to the movement of the arm 16 with respect to the steering column body 14, since the steering column body 14 is fixedly connected to the bracket 2 in the longitudinal direction, and the bracket is fixed after being installed in the vehicle. It should be noted that the steering column body 14 can be pivotally assembled with respect to the bracket 12 so as to additionally enable height adjustment of the steering wheel in the passenger compartment, yet always maintaining a longitudinal connection with the bracket 12.

[0055] In the example from Figure 1 the steering column body 14 has a hole 22 in which the arm 16 is slidably assembled so as to enable longitudinal movement of the arm 16.

[0056] Supplementally thereto, the steering shaft 18 is translationally connected to the arm 16 such that the steering shaft is driven by the arm during longitudinal movement of the arm 16. It goes without saying that, based on the fact that the steering shaft 18 carries the steering wheel and is at the same time translationally fixedly connected to the movement of the arm 16, the relative positioning of the arm 16 with respect to the steering column body 14 determines the position of the steering wheel in the passenger compartment of the vehicle.

[0057] In practice, the arm 16 acts like a muscle: its actuation causes a change in the longitudinal extension of the steering shaft 18 and correspondingly causes the movement of the steering wheel fixedly connected to the steering shaft 18.

[0058] Advantageously, the steering shaft 18 is telescopic along its extension in the arm 16 so as to maintain its ability to transmit the rotation of the steering wheel and at the same time ensure translational freedom.

[0059] The movement of the arm 16 relative to the steering column body 14 is ensured by an electromechanical adjustment actuator 24. The electromechanical actuator 24 includes an electric motor 26, which translationally drives the arm 16 through a drive mechanism 28.

[0060] The drive mechanism 28 particularly includes a motion converter 30 of the lead screw - nut type, which converts the rotation provided by the electric motor 26 into the pushing of the arm 16. The motion converter 30 has a screw 31 and a nut 32 carried by the screw. The nut 32 and the screw 31 have cooperating external or internal threads.

[0061] According to Figure 1In the embodiment shown, the screw 31 can be translationally fixed with respect to the steering column body 14 and rotated about its rod axis AX1. The rod axis AX1 is substantially parallel to the longitudinally oriented axis AX, which coincides with the axis of rotation of the arm 16, which has a tubular shape in this example. In practice, there can be a small angular deviation between the axis AX1 and the axis AX, which does not affect the proper operation of the electromechanical actuator 24.

[0062] The screw 31 is assembled at the steering column body 14 and has a first free end 31a and a second end 31b, at which the rod is stopped to prevent displacement.

[0063] Supplementally thereto, the nut 32 is translationally fixedly connected to the arm 16 in such a way that the nut is fixedly mounted at the arm and is stopped to prevent rotation about the screw 31. The nut 32 extends radially around the screw 31 in the radial direction AY1, where the radial direction AY1 is defined as the direction intersecting orthogonally to the rod axis AX1.

[0064] In the example from Figure 1 it results that the axis AX1 of the screw 31 does not coincide with the axis of rotation AX of the arm 16, so that rotation of the nut 32 cannot be achieved. This necessarily causes the nut 32 to move longitudinally along the screw 31 when the screw 31 rotates. Nevertheless, the steering column assembly 10 according to the invention is not limited to the specific arrangement of the screw 31. Other arrangements of the screw 31 are allowed if the following two conditions are met:

[0065] - The nut 32 is translationally fixedly connected to the arm 16, and

[0066] - The screw 31 carrying the nut 32 is fixedly connected to the steering column body 14 in the longitudinal direction.

[0067] As a non-limiting example, it can be provided that the nut 32 is stopped along the screw 31 to prevent rotation by a specially designed locking mechanism.

[0068] Looking at the steering column assembly 10 arranged in a vehicle, the electric motor 26 is then activated during the step of setting the longitudinal position of the steering wheel in order to rotate the screw 31. In response thereto, the nut 32 moves along the screw 31 and in its longitudinal movement drives the arm 16 (to which the nut is fastened). Depending on the thread direction of the screw 31 and thus of the nut, the rotation of the screw caused by the electric motor 26 causes the arm 16:

[0069] - The so-called retracted direction denoted by S1, which guides the steering wheel closer to the driver's seat of the vehicle; - or the so-called extended direction denoted by S2, which guides the steering wheel away from the driver's seat

[0070] with the passage of time

[0071] In the context of the present invention, the motion converter 30 exhibits reversibility so as to be able to utilize the ISO-power of the electric motor 26 to achieve a higher speed of movement of the nut 32 along the screw and thus a higher speed of setting of the longitudinal position of the steering wheel. This reversible property of the motion converter 30 corresponds to the feasibility of rotation of the screw 31 in order to translationally drive the nut 32, but conversely also corresponds to the movement of the nut 32 in the longitudinal direction in order to cause, in response thereto, rotation of the screw 31.

[0072] Nevertheless, an accidental translational movement of the nut 32, that is to say outside the setting phase, is still not desired. Thus, when the electric motor 26 is in a stationary state, that is to say the setting is not activated, the fixed position of the steering wheel must be ensured. The force exerted by the driver on the steering wheel during the driving state must not be allowed to cause movement of the steering wheel by means of the electromechanical adjustment actuator 24.

[0073] The basic concept on which the present invention is based thus aims to lock the screw 31 against rotation by means of the motor 26 outside the setting phase, thereby preventing longitudinal movement of the nut 32. If the nut 32 is locked during the non-setting phase, this causes locking of the position of the arm 16 and thus of the position of the steering wheel, the position of which is determined by the position of the arm 16.

[0074] In this regard, the main particularity of the present invention is that the drive mechanism 28 has a mechanical coupling device 38 in order to allow rotation of the screw by means of the electric motor and at the same time to lock the rod against rotation by means of the nut.

[0075] As can be seen in detail in Figure 2 the drive mechanism 28 has the form of a bevel gear transmission which is integrated into a housing 40 fastened to the steering column body 14. The housing 40 has fastening holes for this purpose, which are marked with 41. The electric motor 26 is likewise fastened to the housing 40, thereby ensuring the assembly of the electric motor 26 at the steering column body 14. The connection between the electric motor 26 and the drive mechanism 28 forms a so-called transmission motor unit.

[0076] The drive mechanism 28 has a drive shaft 42 which is coupled to an invisible motor output shaft. The drive shaft 42 has the form of a worm and extends in a direction orthogonal to the longitudinal direction. The rotation of the drive shaft caused by the motor is transmitted to the screw 31 via the mechanical coupling device 38, which forms the interface between these two elements.

[0077] Referring to Figure 2 , Figure 3A and 3B, the mechanical coupling device 38 is formed by a combination of a ring 44, a first transmission mechanism 46, a second transmission mechanism 48, a pair of rolling elements 50, and a pair of elastic elements 52.

[0078] These elements will be described below with reference to the screw 31 and the drive shaft 42, as their dimensions and orientations are defined with respect to their defined positions at the interface between the screw 31 and the drive shaft 42.

[0079] The first mechanism 46 has the form of a structural assembly formed by a rigid connection between a pinion 54 and a tongue 56 that are joined or integrally constructed. The pinion 54 is arranged concentrically with the screw 31 along AX1. The pinion has an external tooth portion configured to cooperate with the drive shaft 42. In the example of the figures, the drive shaft 42 and the pinion 54 are helical gears with a left-handed rise, which produces a reduction ratio. The pinion 54 has a through-opening in its middle that defines a cylindrical inner wall 54a with a longitudinal axis. In addition, the pinion is defined in the longitudinal direction by two side walls 54b that are perpendicular to the longitudinal direction. The side walls 54b can respectively correspond to disks or faces that form the negative structure of the gear profile of the pinion 54. The side walls 54b are defined radially by the corresponding external radial profile of the tooth portion of the pinion 54 and by the inner profile defined by the cylindrical inner wall. The tongue 56 has the form of a cylindrical section. The tongue extends longitudinally beyond the side wall 54b of the pinion 54 facing the screw 31. More precisely, the tongue 56 extends in an arc-shaped section in the AZ1 direction corresponding to the deflection direction around the axis AX1.

[0080] It should be noted that the electromechanical actuator 24 is not limited to the orientation of the electric motor 26 and correspondingly is also not limited to the orientation of the drive shaft 42 and the shape of the threads of the drive shaft 42 and the pinion 54. In the present example, it applies that the threads of the pinion 54 can form the required helical gear mechanism, starting from the fact that the drive shaft 42 extends orthogonally to the longitudinal direction of the screw 31. However, other orientations of the electric motor 26 and thus the drive shaft 42 can also be set by changing the threads of the pinion 54 without departing from the framework of the present invention.

[0081] The second mechanism 48 has the form of a stepped shaft with a hollow body. The second mechanism extends concentrically with the screw 31 along AX1 in the longitudinal direction. The second mechanism consists of a cascaded structure of concentric rings that extend respectively in the longitudinal extension of the other rings. Specifically, the second mechanism 48 is defined in the longitudinal direction by an interlocking ring 58 and a terminating ring 60. When observing the longitudinal direction defined from the screw 31 to the drive shaft 42, the following components can be identified at the second mechanism 48: a coupling ring 62 that extends the interlocking ring 58, a guiding ring 64 that extends the guiding ring 64, and a terminating ring 60 that extends the guiding ring 64.

[0082] Functionally, the engaging ring 58 is shaped such that it advantageously receives the second end 31b of the screw 31 by press-fitting to ensure the rotational coupling of the second mechanism 48 with the screw 31. This particularity causes a translational locking of the screw 31 at the drive mechanism. The engaging ring 58 additionally serves as a longitudinal stop against which the tongue 56 abuts.

[0083] The guide ring 64 is slidably fitted into the opening of the pinion 54 to ensure the concentricity of the first and second mechanisms.

[0084] The coupling ring 62 has a radial projection 66. The radial projection 66 extends over a circumferential portion of the coupling ring 62. Two radial recesses 68 are formed in the projection 66, and one of the two rolling elements 50 and one of the two elastic elements 52 are respectively arranged in the two radial recesses. The recesses extend circumferentially at the circumferential ends of the radial projection 66 respectively. In the example from Figure 3A and 3B the recess 68 is defined longitudinally by the remaining walls 66 of the two projections. The protruding remaining walls 66 are responsible for holding the rolling element 50 longitudinally.

[0085] However, the present invention is not limited to the specific shape of the projection 66 and also allows holding the rolling element and the spring element between the first and second mechanisms extending oppositely longitudinally.

[0086] The rolling element 50 has the form of a roller oriented longitudinally, and the elastic element has the form of a spring respectively formed by a metal strip.

[0087] The coupling ring 62 is oriented longitudinally at a section C of the so-called overlapping portion of the tongue 56 of the mechanical coupling device 38 and the first mechanism 46.

[0088] In the example from the drawings, the ring 44 has a cylindrical outer surface and an inner surface. The ring is oriented such that the axis of rotation of its inner surface coincides with the axis AX1 of the screw 31. The ring is press-fitted into a corresponding recess formed in the housing 40 at its outer surface to lock its rotation along AX1, while its inner surface slidably surrounds the first and second mechanisms at the overlapping section C.

[0089] It should be noted that the outer surface of the ring 44 is not limited to having a circular profile. The outer surface can in particular be prismatic, that is, have a polygonal profile. In this case, it goes without saying that when the ring is press-fitted into the recess in the housing 40, rotation of the ring 44 cannot be achieved, and the recess is shaped such that it has a profile that forms a negative structure of the profile of the outer surface.

[0090] Alternatively, the ring 44 can also be a component part of the housing 40, i.e., it is formed directly by the housing 40. In this case, it goes without saying that the housing 40 easily forms an annular inner surface that serves as the inner surface of the ring 44.

[0091] The drive mechanism 28 further includes:

[0092] - a ball bearing 70 having an outer ring fixedly carried by the housing 40 and an inner ring surrounding the end ring 60. As can be understood, such an arrangement forms a bearing for rotationally guiding the screw 31 by the second mechanism 48;

[0093] - an adjusting ring 72 that fits into the housing 40 and through which a threaded element 74 extends, and the threaded element is clamped into the end ring 60 to help axially hold the screw 31 with respect to the steering column body 14.

[0094] According to the attached Figure 4 and Figure 5 describe the arrangement of the elements extending at the overlapping section C.

[0095] The inner wall of the ring 44, marked 76, surrounds the protrusion 66 and the tongue 56. This inner wall extends radially around the notch 68 to jointly define the groove 78.

[0096] Each groove 78 is as follows:

[0097] - is defined radially not only by a track 80 corresponding to the radial profile of the protrusion 66 obtained from the associated notch 68 but also by the inner surface of the ring 44, thereby ensuring the radial retention of the corresponding rolling element 50;

[0098] - is defined circumferentially by a groove bottom wall 82 corresponding to the circumferential end of the protrusion obtained from the associated notch 68 and by a groove opening 84 corresponding to the circumferential end of this notch

[0099] to define.

[0100] As can be understood, the notch 68 corresponds to the volume that is grooved out in the protrusion 66 and defines the circumferential extension of the protrusion.

[0101] The main special feature lies in the orientation of the grooves. The grooves 78 have oppositely arranged orientations, i.e., the circumferential direction defined by the direction from the bottom wall 82 towards the groove opening 84 of one groove corresponds to the oppositely arranged direction of the other groove.

[0102] Each track 80 of the second mechanism 48 is shaped such that the radial extension of the corresponding groove 78 decreases as it gets closer to the groove opening 84 in the circumferential direction. This radial cross-sectional contraction is designed such that the radial extension of the groove 78 measured at the groove opening 84, marked with M in Figure 5 is less than the radial dimension of the rolling element 50 marked with D. It follows that the rolling element 50 cannot disengage from the groove 78 through the groove opening 84.

[0103] Thus, at each groove 78, the assigned rolling element 50 is held in the groove not only by the groove bottom wall 82 but also by the groove opening 84 in the circumferential direction.

[0104] The rolling element 50 has the shape of a roller that is oriented such that its axis extends in the longitudinal direction.

[0105] Regarding the elastic elements 52, these elastic elements respectively have the form of metal strips and are respectively arranged pre-tensioned between the groove bottom wall 82 of a single groove 78 and the roller 50. These elastic elements are constructed such that they passively press the roller 50 away from the groove bottom wall 82 under an elastic pre-tensioning force in order to press the roller in the direction of the groove opening 84. Since the roller 50 cannot disengage from the groove 78 through the groove opening 84, the roller 50 is thus held in a clamped position between the track 80 and the inner ring surface 76.

[0106] In practice, the pre-tensioning force is ensured by designing the metal strip such that the installation of the metal strip between two protruding remaining walls forces the deformation of the metal strip.

[0107] Since the roller 50 cannot disengage from the groove 78 through the groove opening 84, the roller 50 is thus held in a clamped position between the track 80 and the inner ring surface 76.

[0108] In practice, the structural assembly is formed by the groove 78 and a pair formed by the roller 50 and the spring 52 arranged in the groove, and each structural assembly represents a so-called locking unit 90.

[0109] The following will explain the dynamics of rotation or the locking of the rotation of the screw 31 based on Figure 6A and 6B where, for better understanding, the components of the same locking assembly are marked with the letter a or the letter b.

[0110] Refer to Figure 6ADuring the non-setting phase, that is to say when the electric motor 26 is in a stationary state, the longitudinal pulse acting on the nut 32 tends to put the screw 31 into rotation. Depending on the direction of the longitudinal force applied to the nut 32, this rotation can correspond to the screwing in or out of the rod 31.

[0111] It is thus considered that the screw 31 tends to rotate about its rod axis AX1 in any direction marked R1. Since the second mechanism 48 is rotationally fixed to the screw 31, it goes without saying that the second mechanism 48 also tends to be put into rotation in the direction R1.

[0112] In the example from Figure 6A this direction R1 is set opposite to the direction of the pre-tension force exerted by the spring 52a on the roller 50a of the first locking assembly 90a. Since the spring 52a presses the roller 50a in a direction opposite to the direction R1 in order to keep this roller locked between the inner wall 76 of the ring defining the first assembly and the track 80a, the second mechanism 48 is stopped from rotating in the direction R1.

[0113] This is because in order to enable the rotation of the second mechanism 48, the roller 50a must be able to rotate about itself by rolling on the inner wall 76 of the ring. However, this rotation is prevented by the clamping action exerted on the roller, which is itself clamped between the track 80a and the inner wall 76 of the ring due to the combined effect of the reduced radial extension of the groove 78a and the elastic pre-tension force of the spring 52a.

[0114] Since the second mechanism 48 is stopped from rotating in the direction R1, the screw is stopped from rotating in the same direction R1.

[0115] It is also considered that the screw 31 tends to rotate about its rod axis AX1 in a direction R2 opposite to the direction R1 by the longitudinal force applied to the nut 32, and then the second locking assembly 90b ensures anti-rotation.

[0116] Similarly, the clamping action exerted based on the combined effect of the reduced radial extension of the groove 78b and the elastic pre-tension force of the spring 52b on the roller 50b of the second assembly 90b prevents the rotation of this roller 50b. This clamping action is in this case generated by the elastic pre-tension force that presses the roller 50b in a direction opposite to the direction R2 in order to keep this roller locked between the inner wall 76 of the ring defining the second assembly and the track 80b.

[0117] Reference Figure 6B During the setting phase, that is to say when the electric motor 26 is activated to put the drive shaft 42 into rotation, the first mechanism 46 is rotationally driven because its pinion 54 is engaged in the drive shaft 42.

[0118] First, observe the rotation of the first mechanism 46 in the direction S1. The rotation in the direction S1 causes the tongue portion 56 to rotate in the direction of the groove 78a of the first locking assembly 90a.

[0119] Specifically, the first circumferential end face 56a of the tongue portion 56 abuts against the first circumferential end wall of the protrusion 66 marked with 66a that extends radially until the groove opening 84a, as Figure 6B shown. The first circumferential end face 56a of the tongue portion 56 also extends radially along the groove opening 84a, so that the abutment of the first circumferential end face 56a against the first circumferential end wall 66a of the protrusion causes it to press the roller 50a in the direction of the groove bottom 82a of the groove 78a.

[0120] If the torque provided by the electric motor 26 is sufficient, the pressure exerted on the roller 50a by the first circumferential end face 56a of the tongue portion 56 can overcome the preload of the spring 52a. In this case, the roller 50a is caused to disengage from its clamping position in such a way that the roller moves in the direction of the groove bottom 82a against the preload of the spring 52a.

[0121] Once the first circumferential end face 56a of the tongue portion 56 abuts against the first circumferential end wall 66a of the protrusion 66, the first mechanism drives the second mechanism in its rotation. Correspondingly, since the first locking unit 90a does not react against the rotation of the roller 50a due to the release of the roller 50a, the rotational coupling of the first mechanism and the second mechanism in the direction R1 becomes effective. The screw 31, which is rotationally fixedly connected to the second mechanism 48, then rotates in the direction R1.

[0122] Furthermore, it should be noted that the second locking unit 90b is not responsible for preventing the rotation of the second mechanism 48 in this first rotational direction R1. Thus, the roller 50b of the second locking unit is naturally driven in the direction of the groove bottom 82b due to the rotation of the second mechanism 48 caused by the first mechanism 46 and can thus roll on the inner wall 76 of the ring 44. This is due on the one hand to the fact that:

[0123] - If the torque applied to the first mechanism 46 is sufficient to overcome the preload applied to the roller 50a by the spring 52a of the first locking assembly 90a; then

[0124] - The torque applied to the second mechanism is also sufficient to cause the roller 50b to move in the direction of the groove bottom 82b against the preload of the spring 52b of the second locking assembly 90b.

[0125] Similarly, in the case of rotationally driving the first mechanism 46 in the direction R2 opposite to the direction R1, the rotation of the screw 31 in the direction R2 can be achieved.

[0126] The second circumferential end face 56b of the tongue portion 56 abuts against the second circumferential end face 66b of the projection 66 that extends radially up to the groove opening 84b.

[0127] Similar to the first circumferential end face 56b, the second circumferential end face 56b also extends radially along the groove opening 84b, so that the abutment of the second circumferential end face 56b of the tongue portion 56 against the second circumferential end face 66b of the projection 66 causes it to press the roller 50b in the direction of the groove bottom 82b of the groove 78b.

[0128] If the torque provided by the electric motor 26 is sufficient, the pressure exerted on the roller 50b by the second circumferential end face 56b of the tongue portion 56 can overcome the preload force of the spring 52b. The detachment of the roller 50b from its clamping position occurs in such a way that the roller moves in the direction of the groove bottom 82b against the preload force of the spring 52b.

[0129] Once the first circumferential end face 56b of the tongue portion 56 abuts against the second circumferential end face 66b of the projection 66, the first mechanism 46 drives the second mechanism 48 in its rotation. Since the first locking unit 90a does not act against this rotation due to the release of the roller 50b, the rotational coupling of the first mechanism and the second mechanism in the direction R2 becomes effective. The screw 31, which is rotationally fixedly connected to the second mechanism 48, then rotates in the direction R2.

[0130] Due to the symmetry effect when the first mechanism 46 rotates in the direction R1, the first locking unit 90a is not responsible for preventing the rotation of the second mechanism 48 in this second rotation direction R2. Thus, the roller 50a of the first locking unit 90a is naturally driven in the direction of the groove bottom 82a due to the rotation of the second mechanism 48 caused by the first mechanism 46 and can then roll on the inner wall 76 of the ring 44.

[0131] In the previous description based on the drawings, the tongue portion 56 is shaped such that the circumferential end faces 56a and 56b respectively not only:

[0132] - form a release section that extends circumferentially relative to the groove opening so as to be suitable for abutting against the roller and pressing the roller in the direction of the corresponding groove bottom; and

[0133] - form a support section that extends circumferentially relative to one of the walls of the second mechanism so as to be suitable for abutting against the wall and driving the second mechanism in its rotational movement.

[0134] However, it should be noted that the present invention is not limited to this particularity. In practice, the tongue portion 56 can extend radially, so that the tongue portion only has circumferential end faces 56a, 56b, which are aligned with the openings of the grooves 78a, 78b of the first locking assembly or the second locking assemblies 90a, 90b in the circumferential direction.

[0135] In this arrangement, the dynamics of the rotational coupling of the first mechanism and the second mechanism 46, 48 can be maintained as described previously in the setting phase. The only difference is that the rotation of the second mechanism 48 caused by the first mechanism 46 means that the circumferential end faces 56a, 56b of the tongue portion press the rollers 50a, 50b towards the bottom of the grooves 82a, 82b until the springs 52a, 52b are sufficiently deformed to transfer the torque from the first mechanism 46 to the second mechanism 48.

[0136] Once in practice the rollers 50a, 50b press the springs 52a, 52b sufficiently against the bottom walls 82a, 82b of the grooves, they jointly form a material continuity between the observed circumferential end faces 56a, 56b and the opposing bottom walls 82a, 82b of the grooves. It should be noted that the springs are shaped in such a way that the deformation they undergo remains within the elastic range in order to maintain their ability to press the rollers towards the groove openings to clamp the rollers.

[0137] In Figure 6A and 6B an example of, random directions of rotation are used in order to define the dynamic interaction of the components of the mechanical coupling device 38. It goes without saying that depending on the orientation of the threads of the screw 31 and the nut 32:

[0138] - The first rotation direction R1 can correspond to the rotation of the rod, which causes the nut to move in the direction S1 or S2 from Figure 1 ; and thus

[0139] - The second rotation direction R2, which is opposite to the direction R1, can correspond to the rotation of the rod, which causes the nut to move in the direction S2 or S1 from Figure 1

[0140] Independent of the pushing direction S1 or S2 corresponding to the rotation direction R1 or R2 of the screw 31, as described, the symmetrical combination of the locking units 90a, 90b of the mechanical coupling device 38 can achieve the anti-pushing of the nut 32 in one direction or the other caused by the anti-rotation of the screw 31.

[0141] It follows therefrom that the mechanical coupling device 38 can achieve locking the steering wheel carried by the steering shaft 18 in its position in the driving state in which the electric motor 26 is deactivated. ​

[0142] It should be noted in this regard that the coupling device 38 is not limited to its described form and in particular not to the existence of two locking units 90a, 90b. It can thus be expected that the steering wheel, i.e. the nut whose position defines the position of the steering wheel, is only blocked against displacement in the direction S1 or S2 of the longitudinal pulse applied to the steering wheel or the nut 32.

[0143] In this context, within the framework of the present invention, it is possible to provide, as provided, a single locking unit 90 which blocks the screw 31 against rotation in a single rotational direction, R1 or R2. Preferably, the selected rotational direction R1 or R2 of the screw (for which the coupling device 38 ensures anti-rotation in the non-set state of the steering wheel) corresponds to the translational direction S1. In fact, it is more likely that in the driving state, especially in the case of an accident (the energy of which throws the driver forward), the vehicle driver presses against the steering wheel in front of him.

[0144] In the example of the figures, the roller 50 is used as the rolling element of the locking unit 90, wherein, however, the present invention does not limit this particularity. The roller can in particular be replaced by ball or barrel roller bearings.

[0145] The present invention is also not limited to the use of a metal strip spring. In practice, any type of elastic element can be selected as long as it applies pressure to the rolling element in order to clamp the rolling element between the track 80 of the second mechanism and the inner wall 76 of the ring 44.

[0146] The coupling device 38 is thus described such that it relates to a transmission mechanism element which is arranged in the transmission mechanism housing 40 and forms an interface for reducing the rotational speed. In particular, the first mechanism 46 is described such that it has a pinion 54 which meshes with the drive shaft 42 directly driven by the electric motor 26 in order to produce a reduction ratio.

[0147] It should be noted that the coupling device 38 is not limited to a specific arrangement. In practice, the coupling device 38 can be arranged along the drive mechanism 28 at any arbitrary defined position as long as the coupling device fulfils its function of locking / rotating the screw 31. In other words, according to the present invention, it is not stipulated that the coupling device is an integral component of the transmission mechanism module and in particular that the first mechanism has a pinion 54 provided for cooperation with the drive shaft 42.

[0148] The coupling device 38 is described such that it counteracts an undesired influence which is associated with the use of a screw-nut type reversible transducer in the electromechanical actuator 24 for setting the position of the steering wheel in the steering column structural assembly. The coupling device enables such a differentiation of the rotation of the screw 31 that the rotation is allowed when desired and prevented when rotation is not intended. It should be noted, however, that the invention is not limited to a specific use.

[0149] On the one hand, a second mechanism 48 is described as being coupled to the screw 31. It should be noted that this particularity results directly from the arrangement of the motion transducer 30 and is not limited in itself. Thus, within the framework of the invention, the functional mode of the transducer can be reversed, in which case the screw 31 is translationally fixedly connected to the arm 16 and, complementarily, the nut 32 is translationally fixedly connected to the steering column body 14 and is rotationally driven via the drive mechanism 28 by the electric motor 26 in order to achieve a similar functional mode. In this case, the coupling device 38 is mounted reversely.

[0150] On the other hand and more generally, the use of the coupling device 38 according to the invention is not limited to applications in electromechanical adjustment actuators 24 having a reversible screw-nut transducer. The coupling device 38 can be a component in any mechanism in which the rotation of one shaft is desired to be selectively locked or allowed by a single locking unit in one direction or by two locking units in two directions by another shaft. The shafts correspond to mechanical mechanisms which transmit forces in the form of torque and rotational movement, and each mechanical mechanism can be referred to as an element which can rotate about a rotational axis, such as a pinion or a gear, regardless of its thickness.

Claims

1. A mechanical coupling device (38) for selectively rotationally coupling a first shaft to a second shaft to allow rotation of the second shaft by the first shaft and simultaneously lock rotation of the first shaft by the second shaft, wherein, the coupling device comprises the following components: - a first rotating mechanism (46) which defines a structural element for rotationally and fixedly connecting to the first shaft or forming the first shaft; - a second rotating mechanism (48) which defines a structural element for rotationally and fixedly connecting to the second shaft or forming the second shaft, wherein the second mechanism (48) extends concentrically with the first mechanism (46) along a longitudinal axis (AX1); - a rotationally fixed ring (44) which radially surrounds the first mechanism and the second mechanism (46, 48) along an overlapping section (C) with respect to the longitudinal axis (AX1), where the first mechanism and the second mechanism overlap in the longitudinal direction; - a first locking unit (90a) for locking rotation of the first shaft by the second shaft in a first rotation direction (R1), wherein the first locking unit (90a) comprises a first groove (78a) and a first elastic element (52a) and a first rolling element (50a) encapsulated in the first groove (78a), wherein: -- the first groove (78a) extends in a circumferential direction (AZ1) which is defined as a deflection direction around the longitudinal axis (AX1), wherein the first groove is defined between a groove bottom wall (82a) formed by the second mechanism (48) and a groove opening (84), and wherein the first rotation direction (R1) is defined as the direction from the groove opening (84a) towards the groove bottom (82a); -- the first groove (78a) is defined radially by a track (80a) formed by the second mechanism (48) and by a cylindrical inner wall (76) of the face of the ring (44) relative to the track (80a), wherein the track (80a) is shaped such that the radial extension of the groove (78a) decreases as it gets closer to the groove opening (84a) in the circumferential direction (AZ1), so that the rolling element (50a) cannot escape from the groove (78a) through the groove opening (84a); 82 -- the first elastic element (52a) is arranged between the groove bottom wall (82a) and the first rolling element (50a), wherein the first elastic element (52a) passively presses the first rolling element (50a) away from the groove bottom wall (82a) under an elastic preloading force to press the first rolling element towards the groove opening (84a) until the first rolling element (50a) is held in a clamping position between the track (80a) and the inner wall (76) of the ring; Wherein, the first mechanism has a release section (56a) to allow rotation of the second shaft along a first rotation direction (R1) by the first shaft. The release section (56a) extends circumferentially relative to the groove opening (84a) to be adapted to, when the first mechanism (46) rotates along the first rotation direction (R1) opposite to the pre-tightening direction of the first elastic element (52a), abut against the first rolling element (50a) and press the first rolling element in the direction of the groove bottom (82a), and simultaneously achieve the following torque to overcome the pre-tightening force of the first elastic element (52a) and disengage the first rolling element (50a) from the clamping position.

2. The mechanical coupling device (38) according to claim 1, the mechanical coupling device including a second locking unit (90b) for rotation of the first shaft along a second rotation direction (R2) opposite to the first rotation direction (R1) by the second shaft. Wherein, the second locking unit (90b) has: a second groove (78b) defined between the ring (44) and the first mechanism and the second mechanism (46, 48); and a second elastic element (52b) and a second rolling element (50b) encapsulated in the second groove (78b), wherein: - the second groove (78b) extends circumferentially and is defined between a corresponding groove bottom wall (82b) formed by the second mechanism (48) and a corresponding groove opening (84b) here. The second groove (78b) is oriented such that the direction from the opening (84b) of the second groove towards the bottom wall (82a) of the second groove corresponds to the second rotation direction (R2); - the second groove (78b) is defined radially through a track (80b) formed by the second mechanism (48) and through a columnar inner wall (76) of the ring relative to the track (80b). The track (80b) is shaped such that the radial extension of the second groove (78b) decreases as it gets closer to the opening (84b) of the second groove along the circumferential direction (AZ1), so that the second rolling element (50b) cannot disengage from the second groove (78b) through the groove opening (84b); - the second elastic element (52b) is arranged between the bottom wall (82b) of the second groove and the second rolling element (50b). The second elastic element (52b) passively presses the second rolling element away from the bottom wall (82b) of the second groove to press the second rolling element in the direction of the opening (84b) of the second groove until the second rolling element (50b) is held in a clamping position between the track (80b) and the inner wall (76) of the ring. And wherein, the first mechanism has a second release section (56b) to allow rotation of the second shaft along a second rotation direction (R2) by the first shaft, wherein the second release section (56b) extends circumferentially (AZ1) relative to the opening (84b) of the second groove so as to be adapted to, when the first mechanism (46) rotates along the second rotation direction (R2) opposite to the pre-tensioning direction of the second elastic element (52b), abut against the second rolling element (50b) and press the second rolling element towards the bottom wall (82b) of the second groove, and simultaneously achieve the following torque to overcome the pre-tensioning force of the second elastic element (52b) and disengage the second rolling element (50b) from the clamping position.

3. The mechanical coupling device according to claim 1 or 2, wherein, when the rolling elements (50a; 50b) are released from the clamping position by the release section, rotation of the second shaft along the rotation direction (R1; R2) locked by the corresponding locking unit (90a, 90b) by the first shaft is ensured by the support surfaces (56a; 56b) of the first mechanism (46) abutting against the support surfaces (66a; 66b) of the second mechanism (48), wherein the first support surface and the second support surface can at least partially overlap each other circumferentially (AZ1).

4. The mechanical coupling device according to claim 1 or 2, wherein, rotation of the second shaft along the rotation direction locked by the corresponding locking unit (90a; 90b) by the first shaft is ensured by the rolling elements (50a; 50b) and the corresponding elastic elements (52a; 52b), and the rolling elements and the corresponding elastic elements form a contact interface between the release section (56a; 56b) of the first mechanism (46) and the groove bottom wall (82a; 82b) of the locking unit (90a; 90b).

5. A steering column structural assembly (10) for a vehicle, such as a steering system of a motor vehicle, the steering column structural assembly having the following components: - a steering column body (14) which is arranged for fixedly assembling at a vehicle structure; - an arm (16) which is carried by the steering column body (14) and extends herein along a longitudinal direction (AX), wherein, the arm (16) at least partially fits into the steering column body (14) and can be translated along the longitudinal direction with respect to the steering column body (14); - an electromechanical actuator (24) for translating the arm (16) along the longitudinal direction, wherein the electronic actuator includes the following components: -- an electric motor (26) for performing rotary drive; -- A motion converter (30) of the ball screw type that converts the rotation provided by the electric motor (26) into the pushing movement of the arm (16), wherein the motion converter (30) includes: a screw (31) that is translationally fixed with respect to the steering column body (14); and a nut (32) that is rotationally fixed and is translationally fixed to the arm (16) in the longitudinal direction (AX). -- The mechanical rotational coupling device (38) according to any one of the preceding claims, which is used to rotationally couple the screw (31) with a drive shaft (42) that is rotationally driven at the output end of the electric motor (26).

6. The steering column structure assembly (10) according to claim 5, wherein, the mechanical rotational coupling device (38) is an integral component of the drive mechanism (28), and this integral component is arranged in a housing (40) fastened to the steering column body (14), and the rotation provided by the electric motor (26) is transmitted to the screw (31) through this integral component, wherein the drive mechanism (28) includes the drive shaft (42), which is driven by the electric motor (26), wherein the first mechanism (46) includes a pinion (54) that extends beyond the overlapping section (C), and wherein the pinion (54) has teeth that cooperate with the teeth of the drive shaft (42).

7. The steering column structure assembly (10) according to claim 6, wherein, the ring (44) is formed by the housing (40).

8. The steering column structure assembly (10) according to claim 6, wherein, the ring (44) is mounted on the housing (40).

9. The steering column structure assembly (10) according to any one of claims 5 to 8, wherein, one or more of the rolling elements (50a; 50b) are rollers.

10. The steering column structure assembly (10) according to any one of claims 5 to 8, wherein, one or more of the elastic elements (52a; 52b) are formed by metal strips.

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