Linear guiding function for spindles

Abstract

The present invention relates to a steering system (1) for steer-by-wire steering of a vehicle, and to a vehicle to be steer-by-wire steered which comprises said steering system (1), the system (1) comprising: a rack bar (20) for displacing steered wheels (14) of the vehicle; an actuator (40) configured to move the rack bar (20) in an axial direction (A) of the rack bar (20); and a guiding member (30) for guiding the rack bar (20), wherein the guiding member (30) is configured to circumferentially surround and slidingly engage a guided portion (26) of the rack bar (20) so as to allow the rack bar (20) to move in the axial direction (A) while preventing the rack bar (20) to move in a circumferential direction (U) and radial direction (R) of the rack bar (20); wherein the guided portion (26) of the rack bar (20) comprises a tapered guiding groove (22) having two engaging faces (23) opposing each other in the circumferential direction (U) of the rack bar (20); wherein the guiding member (30) comprises: a guiding member housing (31), and a pre-tensioned engagement member (36) arranged in the guiding member housing (31) and having a tapered rack bar engaging portion (64), a housing engaging portion (68) and a pre-tensioning means (70), wherein the guiding member housing (31) has a holding portion (32) for holding the pre-tensioned engagement member (36), the holding portion (32) including two holding faces (33) opposing each other in the circumferential direction (U) of the rack bar (20), wherein the pre-tensioning means (70) is configured to cause the tapered rack bar engaging portion (64) to engage the engaging faces (23) of the tapered guiding groove (22) with a pre-tension, and to cause the housing engaging portion (68) to engage the holding faces (33) with a pre-tension, and wherein the two engaging faces (23) are respectively formed to point toward the central axis (AX) of the rack bar (20).

Description

[0001]August 02, 2023 1 Applicant: NSK Europe Ltd. "LINEAR GUIDING FUNCTION FOR SPINDLES" Our Ref.: N 5374WO - asc / tha Description The present invention relates to a steering system for steer-by-wire steering of a vehicle and to a vehicle to be steer-by-wire steered, wherein the vehicle includes said steering system. In the prior art, steering systems are known, wherein a driver steers a steering wheel, the steering wheel being connected to a steering column which in turn is engaged with a rack bar, such that the steering column transmits the driver’s turning of the steering wheel to the rack bar. The rack bar is displaced in the vehicle width direction for pivoting the wheels of the vehicle in accordance with the driver’s steering / turning of the steering wheel. Furthermore, electrically as well as hydraulicly supported steering systems are known for supporting a driver of a vehicle during steering by transmitting an additional turning force to the steering column or to the rack bar, in addition to the driver’s steering force supplied by steering / turning the steering wheel. Recently, steer- by-wire systems are under development, wherein the rack bar is moved by an actuator solely on the basis of a steering wheel signal generated in accordance with a steering operation of the steering wheel, without any mechanical connection between the steering wheel and the rack bar. In view of the above, it is an object of the present invention to provide an improved steering system for a vehicle, particularly to provide an improved steer-by-wire steering system for a vehicle. The problem is solved by the subject-matter of the independent claims. Preferred embodiments are defined by the dependent claims. According to an aspect, a steering system for steer-by-wire steering of a vehicle is August 02, 2023 2 provided, the system comprising: a rack bar for displacing steered wheels of the vehicle; an actuator configured to move the rack bar in an axial direction of the rack bar; and a guiding member for guiding the rack bar, wherein the guiding member is configured to circumferentially surround and slidingly engage a guided portion of the rack bar so as to allow the rack bar to move in the axial direction while preventing the rack bar to move in a circumferential direction and radial direction of the rack bar; wherein the guided portion of the rack bar comprises a tapered guiding groove having two engaging faces opposing each other in the circumferential direction of the rack bar; wherein the guiding member comprises: a guiding member housing, a pre-tensioned engagement member arranged in the guiding member housing and having a tapered rack bar engaging portion, a housing engaging portion and a pre-tensioning means, wherein the guiding member housing has a holding portion for holding the pre-tensioned engagement member, the holding portion including two holding faces opposing each other in the circumferential direction of the rack bar, wherein the pre-tensioning means is configured to cause the tapered rack bar engaging portion to engage the engaging faces of the tapered guiding groove with a pre-tension, and to cause the housing engaging portion to engage the holding faces with a pre-tension, and wherein the two engaging faces are respectively formed to point toward the central axis of the rack bar. The guiding member is particularly configured to allow the rack bar to move in the axial direction relative to the guiding member and the actuator, while preventing the rack bar from moving in the circumferential direction and the radial direction of the rack bar relative to the guiding member and the actuator. The steering system for steer-by-wire steering a vehicle as provided herein advantageously ensures precisely guiding the rack bar via the guiding member, and furthermore advantageously renders an engagement between a steering column and the rack bar, which provides a guiding and moving function in the conventional steering systems, unnecessary. Accordingly, the vehicle can particularly be manufactured August 02, 2023 3 without a steering column which connects the steering wheel and the rack bar. This in turn advantageously allows to reduce the weight of the vehicle, reduces manufacturing costs and further allows to provide a convenient steering for a driver, wherein the force for axially displacing the rack bar and for accordingly steering the vehicle is provided by the actuator. The steering system accordingly provides for an efficient steering support for a driver when steering the vehicle. Furthermore, since no engagement and accordingly no crossing point between a steering column and the rack bar is to be configured for the steering system, the rack bar may particularly be axially shortened, wherein the rack bar may for example be adjusted to a predetermined minimal length which still ensures precise steering of the wheels to be steered, which are connected to the rack bar for example via one or more knuckles. Furthermore, owing to the shortening of the rack bar compared to conventional steering systems, a distance between the actuation of the rack bar and the guidance of the rack bar can accordingly be shortened, reducing possible bending stress at the actuator when moving the rack bar, and accordingly ensuring an increased service life of the steering system. Furthermore, the guiding member which circumferentially surrounds and slidingly engages the guided portion of the rack bar advantageously ensures low manufacturing costs and precise guidance of the rack bar along its axial direction, back and forth between the wheels to be steered. Still further, since the guiding member engages the rack bar in a manner which prevents circumferential movement of the rack bar while allowing an axial movement of the rack bar, a simplified actuation via the actuator may be provided, such as a ball screw, for example, such that a linear movement can be applied to the rack bar with advantageously reduced friction. Furthermore, the guiding member which particularly comprises a pre-tensioned August 02, 2023 4 engagement member, which in turn particularly includes the pre-tensioning means, particularly provides for a reduced tolerance of the engagement between the tapered rack bar engaging portion and the tapered guiding groove, particularly between two states in which the rack bar is actuated in opposing directions substantially parallel to the axial direction of the rack bar. This further particularly enhances the steering control of the steering system, which is normally affected in case the tolerance for the engagement between the two states is too large. Thus, the guiding member which is configured to prevent the rack bar to move in a circumferential direction, particularly owing to its pre-tensioned engagement member which is configured to engage the engaging faces of the tapered guiding groove, particularly provides for a steering system with improved prevention of a circumferential movement of the rack bar, and thus with an improved guidance of a rack bar in a steering system for steer-by-wire steering of a vehicle. Specifically, the guiding member and particularly its pre-tensioned engagement member which is configured to engage the engaging faces of the tapered guiding groove with a pre-tension advantageously allows for securely engaging both of the engaging faces of the tapered guiding groove with a pre-tension, and thus allows for securely reducing the tolerance when preventing a circumferential movement of the rack bar. This in turn particularly enhances the steering control of the steering system, which is normally affected in case the tolerance for the engagement toward the tapered guiding groove is too large, particularly when switching the direction in which the rack bar is actuated. Still further, the two engaging faces of the tapered guiding groove opposing each other in the circumferential direction, which are respectively formed to point toward the central axis of the rack bar, allow to reduce or to neutralize a radial force which may act onto the tapered rack bar engaging portion when the rack bar is actuated, and further particularly when the direction in which the rack bar is actuated is changed, particularly changed to the opposite direction. August 02, 2023 5 Accordingly, the steering system as defined above advantageously provides for an improved steering system for a vehicle, particularly reducing the weight of the steering system while ensuring steering accuracy and reducing a steering force which a driver has to be apply for steering the vehicle, which in turn allows to efficiently support a driver. The guided portion of the rack bar may particularly include a constant cross section over a predetermined axial length of the rack bar. Accordingly, the rack bar, along its constant cross section which is at least partially engaged by the guiding member, may axially move back and forth in the axial direction along said predetermined axial length, actuated or moved by the actuator, without losing guidance by the guiding member. The pre-tensioning means may particularly be configured to cause the tapered rack bar engaging portion to snugly engage the engaging faces of the tapered guiding groove with a pre-tension, and to cause the housing engaging portion to engage the holding faces of the guiding member housing. That is, the pre-tensioning means may particularly be configured to cause the tapered rack bar engaging portion to contact both engaging faces of the tapered guiding groove in a pre-tensioned manner. The two engaging faces of the tapered guiding groove may particularly be respectively formed to point toward the central axis of the rack bar, i.e. particularly to point toward the rotation axis of the rack bar. In other words, the two engaging faces of the tapered guiding groove may particularly be respectively formed to be substantially parallel to a radial direction of the rack bar. The two engaging faces of the tapered guiding groove may particularly be respectively formed to at least partially extend substantially in the radial direction of the rack bar and substantially in the axial direction of the rack bar. A friction reducing finish and / or coating may be provided on the surface of the tapered guiding groove, particularly on the two engaging faces, and / or on the surface of the tapered rack bar engaging portion. When viewed in an axial direction, the tapered guiding groove may for example substantially have a wedge-shape or may substantially be wedge-shaped. August 02, 2023 6 Owing to the pre-tensioning means, the contour of the tapered rack bar engaging portion may particularly substantially correspond to the tapered contour of the tapered guiding groove, for example the substantially wedge-shaped contour of the tapered guiding groove, such that a circumferential movement of the rack bar relative to the guiding member and / or relative to the actuator is limited, particularly blocked or prevented, while an axial movement of the rack bar relative to the guiding member and / or relative to the actuator is allowed. The axial movement of the rack bar relative to the guiding member and / or relative to the actuator is particularly allowed within a predetermined axial length at which the guided portion is provided at the rack bar. The guiding member is particularly provided separately and distanced from the actuator. The guiding member particularly does not include or engage with a steering column and / or an actuator for displacing the rack bar. The guiding member housing may particularly be fixable to a frame of the vehicle or with respect to a frame of the vehicle. In a state in which the steering system for steer-by-wire steering of a vehicle is mounted to a vehicle, the guiding member housing may particularly be fixed to a frame of the vehicle or with respect to a frame of the vehicle. This particularly allows to advantageously support the holding portion, which in turn allows to reliably hold the pre-tensioned engagement member in position, particularly to reliably hold the tapered rack bar engaging portion in position for engaging the tapered guiding groove, particularly for engaging the tapered guiding groove over a long working life. In particular embodiments, the actuator may be configured to axially or longitudinally move the rack bar in two substantially axial or longitudinal opposite directions of the rack bar, e.g. particularly to move the rack bar substantially back and forth in its axial direction and / or to move the rack bar substantially left and right in the vehicle width direction. The axial or longitudinal movement of the rack bar advantageously prompts a pivoting of the wheels to be steered about a substantially vertical direction of the respective wheel in accordance with a turning or steering of the steering wheel of the August 02, 2023 7 vehicle, in order to steer the vehicle in the desired direction. This advantageously ensures efficient, convenient and reliable steering of the vehicle in accordance with the steering wheel steered or turned by a driver of the vehicle. In particular embodiments the guided portion of the rack bar includes one or more tapered guiding grooves, wherein each of the tapered guiding grooves may have two engaging faces opposing each other in a circumferential direction of the rack bar. The one or more tapered guiding grooves may be axially and / or circumferentially distant with respect to one another. In particular embodiments, the guiding member includes one or more pre-tensioned engagement members and / or one or more guiding member housings. In exemplary embodiments, more than one pre-tensioned engagement members may be configured to engage the one tapered guiding groove, i.e. the same tapered guiding groove, particularly with its respective tapered rack bar engaging portion. The more than one pre-tensioned engagement members may for example be configured to engage one tapered guiding groove at axially distant positions. The engagements of the tapered guiding groove by more than one pre-tensioned engagement member advantageously further reduces the tolerance in the engagements of the tapered guiding groove, particularly when changing the direction of the actuation of the rack bar. In further exemplary embodiments, more than one pre-tensioned engagement members may for example be configured to engage circumferentially and / or axially distant tapered guiding grooves. This particularly enhances the reliability of the engagement of more than one tapered guiding groove via more than one pre-tensioned engagement member. The one or more pre-tensioned engagement members may be disposed so as to August 02, 2023 8 correspond to the one or more tapered guiding grooves. The one or more pre- tensioned engagement members may particularly be configured to form a form-fit engagement with respect to the one or more tapered guiding grooves. Said form-fit engagement particularly configures a form-fit with respect to the circumferential direction of the rack bar and with respect to the radial direction of the rack bar. That is, said form-fit engagement particularly provides for limiting or preventing circumferential and / or rotational movement of the rack bar, and particularly provides for limiting or preventing radial movement of the rack bar. The one or more tapered guiding grooves, and accordingly the one or more pre- tensioned engagement members may be provided at predetermined positions regularly or irregularly distributed along the circumference and / or axial length of the rack bar, particularly the guided portion of the rack bar. For efficiently preventing the movement of the rack bar in the circumferential direction, the guiding member or particularly the guiding member housing may preferably be rotationally fixed, for example by securing or mounting the guiding member housing of the steering system to a frame or to a vehicle body portion of the vehicle, such that the guiding member housing cannot rotate. In further particular embodiments, the guiding member housing may be positionally fixed, i.e. the guiding member housing may particularly be rotationally fixed as well as axially fixed, for example by securing or mounting the guiding member housing of the steering system to a frame or to a vehicle body portion of the vehicle, such that the guiding member housing cannot rotate nor move substantially parallel and / or perpendicular to the axial direction of the rack bar. In particular embodiments, the steering system does not include a steering column. Particularly, the steering system does not include a steering column physically or mechanically connecting the steering wheel with the rack bar. However, in particular embodiments, the steering system is configured to electrically transmit an input signal or steering signal reflective of a steering movement or turning of the steering wheel to the actuator, such that the actuator upon receipt of the input signal is configured actuate the rack bar so as to move the rack bar in its axial direction in accordance with August 02, 2023 9 the steering movement or turning of the steering wheel which the input signal is reflective of. The electrical transmission of the input signal to the actuator may particularly include a transmission via an electrically conducting wire, an optical fiber and / or a wireless transmission. The steering system may particularly include a steering control unit which is configured to determine a steering movement or turning of the steering wheel and to transmit an input signal reflective of the steering movement or turning of the steering wheel to the actuator. Accordingly, the steering system provides for an efficient steering support for a driver. In particular embodiments of the steering system, a steering force for pivoting or turning the wheels to be steered may be completely supplied by the actuator, and particularly not at all be supplied by the driver. Herein, in case a direction is given with the indication substantially or about, the respective direction may be understood to be in a range of 0° to 10°, preferably in a range of 0° to 5° deviating from the respective direction. Herein, in case a measure or an amount is given with the indication substantially or about, the respective measure or amount may be understood to be in a range of 0% to 10%, preferably in a range of 0% to 5% deviating from the respective measure or amount. The rack bar as provided herein may particularly have a substantial longitudinal extension, i.e. have an extension in a longitudinal or axial direction which is at least 5 times, or particularly at least 10 times larger than an extension in any other direction perpendicular to said longitudinal or axial direction. The rack bar may at least partially have a rod shape, particularly a substantially circular cross sectional shape. The engaged guided portion of the rack bar at which the guiding member engages the rack bar, as well as an actuated portion of the rack bar at which the actuator may engage the rack bar may be formed at the rod shape or the substantially circular shape. Accordingly, the rack bar is not limited to strictly having a rod shape or a substantially August 02, 2023 10 circular shape. Furthermore, the rack bar may at least partially have a polygonal or otherwise contoured shape in cross section, in order to provide the rack bar with sections for engagement and / or with a predetermined bending stiffness, thus enhancing the longitudinal or axial guidance of the rack bar, as well as a precise steering in the further. A radial direction as described herein is particularly extending radially outward from an axis along the substantial axial or longitudinal extension of the rack bar. Said axis may be contemplated as axis or central axis or rotational axis of a substantial circular portion of the rack bar, which may particularly relate to a rotational symmetry axis for the substantial circular portion of the rack bar. Accordingly, the radial direction particularly points radially outward from the axis of the rack bar. A circumferential direction of the rack bar may particularly be substantially perpendicular to the axial or longitudinal direction of the rack bar, and / or may be substantially perpendicular to the radial direction of the rack bar. In particular embodiments of the steering system, the rack bar may be slidably positioned in the surrounding guiding member. In other words, the guiding member may be configured to surround a whole circumference of the guided portion of the rack bar, particularly at a portion of the rack bar at which the guiding member engages with the rack bar. In some embodiments, the guiding member may include a sliding member, particularly a sliding bush, which may be configured to circumferentially surround the rack bar, and / or to slidingly guide the rack bar. In further particular embodiments, the guided portion of the rack bar and the guiding member may be configured to not include an undercut relative to one another with respect to the direction along which the rack bar is slidably coupled to the guiding member, i.e. with respect to the axial direction of the rack bar. August 02, 2023 11 Advantageously, if a portion from the guided portion to at least one axial end of the rack bar and the guiding member are configured free of an undercut relative to one another with respect to the axial direction, this enables the guiding member to be slidingly mounted onto the guided portion from the at least one axial end of the rack bar, even if the guiding member is formed in one piece or pre-assembled. On the other hand, at least at one axial end of the guided portion of the rack bar, the rack bar and the guiding member may configure a form-fit relative to one another, particularly a form- fit with respect to the axial direction of the rack bar. This form-fit at the axial end of the guided portion of the rack bar configured between the rack bar and the guiding member advantageously allows for limiting the axial movement of the rack bar relative to the guiding member, and accordingly allows to define a pivoting limit for pivoting the wheel(s) to be steered. The form-fit may be configured as an undercut of the of the rack bar relative to the guiding member, for example as a closed or raised cross section at an axial end of the guided portion of the rack bar, particularly the tapered guiding groove of the rack bar, which is particularly closed or raised relative to the outer contour along the guided portion of the rack bar, wherein the outer contour may particularly include a constant cross section along the guided portion of the rack bar, the cross section being substantially perpendicular to the axial direction of the rack bar. In particular embodiments of the steering system, the pre-tensioned engagement member may comprise at least two engagement parts, wherein the pre-tensioning means is configured to push the engagement parts apart in the circumferential direction and / or the radial direction, and / or to apply a rotating force in opposite rotation directions to the engagement parts. The pre-tensioning means may for example be at least partially disposed between the at least two engagement parts. The at least two engagement parts may for example include two or more engagement August 02, 2023 12 parts opposing each other in the circumferential direction of the rack bar. The at least two engagement parts may for example include at least one engagement part facing and / or pre-tensioned engaging one or both engaging faces of the tapered guiding groove, and at least one engagement part facing and / or pre-tensioned engaging one or both holding faces of the holding portion of the guiding member housing. For example, the at least two engagement parts may include at least one radial inner engagement part and at least one radial outer engagement part, wherein the at least one radial outer engagement part is disposed radially outward of the at least one radial inner engagement part. The at least one radial inner engagement part and the at least one radial outer engagement part may for example be configured to face each other and / or to engage each other. The engagement between the at least one radial inner engagement part and the at least one radial outer engagement part may for example be configured to transmit the pre-tension of the pre-tensioning means into a movement of the at least one radial inner engagement part or the at least one radial outer engagement part in the circumferential direction and / or the radial direction. The at least two engagement parts and the pre-tensioning means configured to push the engagement parts apart in the circumferential direction and / or the radial direction, and / or to apply a rotating force in opposite rotation directions to the engagement parts advantageously allow for securely engaging the holding faces of the guiding member housing with the housing engaging portion with a pre-tension, while at the same time engaging the engaging faces of the tapered guiding groove with the tapered rack bar engaging portion with a pre-tension, Furthermore, this particularly allows for configuring the guiding member with a reduced overall size, particularly when the pre-tensioning means is configured to push the engagement parts apart in the circumferential direction and / or the radial direction, and / or to apply a rotating force in opposite rotation directions to the engagement parts. Specifically, when the pre-tensioning means is configured to push the engagement August 02, 2023 13 parts apart in the circumferential direction, and / or to apply a rotating force in opposite rotation directions to the engagement parts, a size of the guiding member in the radial direction may be reduced. In other exemplary embodiments, the pre-tensioned engagement member may comprise only one engagement part, wherein the pre-tensioning means is configured to push the engagement part in the circumferential direction and / or the radial direction. The one engagement part may for example be configured to partially or completely circumferentially surround the rack bar. One engagement part particularly allows for reducing the number of parts of the steering system, which in turn particularly facilities the assembly of the steering system. In particular embodiments of the steering system, the tapered rack bar engaging portion may be formed by at least two of the engagement parts. This advantageously allows for securely engaging both of the engaging faces of the tapered guiding groove with the tapered rack bar engaging portion with a pre-tension. Furthermore, this particularly enhances the steering control of the steering system, which is normally affected in case the tolerance for the engagement of the guiding groove is too large, particularly when switching the direction in which the rack bar is actuated. In particular embodiments of the steering system, the housing engaging portion may be formed by at least two of the engagement parts. This advantageously allows for securely engaging both of the holding faces of the guiding member housing with the housing engaging portion with a pre-tension. Furthermore, this particularly enhances the steering control of the steering system, which is normally affected in case the tolerance for the engagement toward the guiding member housing is too large, particularly when switching the direction in which the rack August 02, 2023 14 bar is actuated. In particular embodiments of the steering system, the rack bar engaging portion, the housing engaging portion and the pre-tensioning means may be formed integrally. The rack bar engaging portion, the housing engaging portion and the pre-tensioning means may for example be integrally formed including an elastomeric material particularly for the pre-tensioning means, and / or the housing engaging portion and the pre-tensioning means may for example be integrally formed as a bridge-shaped part. The bridge-shaped part may have a relaxed state and a pre-tensioned state, wherein in the pre-tensioned state, for example when the bridge-shaped part is assembled to the rack bar, the length of the bridge shaped part may be reduced, particularly providing a pre-tension in a radial outward direction and / or in a radial inward direction. The bridge-shaped part may for example comprise or consist of an elastomeric material, a metal material, for example a spring steel, and / or a plastic material, for example an injection-molded plastic. The bridge-shaped part particularly forms an integral engagement part which, particularly when being in the pre-tensioned state, i.e. particularly when being in the assembled state of the guiding member, is configured to engage the holding faces of the guiding member housing with a pre-tension, while at the same time engaging the engaging faces of the tapered guiding groove with a pre-tension. This advantageously configures the guiding member of the steering system with an easily manufacturable integral engagement part. In particular embodiments of the steering system, the pre-tensioning means may comprise a rubber spring, wherein the rubber spring is optionally molded onto a portion of the pre-tensioned engagement member. August 02, 2023 15 The pre-tensioning means may for example be molded onto one or more of the engagement parts. The pre-tensioning means may for example be arranged between two engagement parts, and / or molded between two engagement parts. This advantageously allows for at least partially pre-manufacturing the pre-tensioned engagement member. This in turn advantageously allows for pre-adjusting the pre- tension of the engagement part(s) relative to the holding faces of the guiding member housing and / or relative to the engaging faces of the tapered guiding groove. In particular embodiments of the steering system, the holding portion of the guiding member housing may comprise a tapered holding groove, the two holding faces being formed by the inner walls of the holding groove. The inner walls of the holding groove may particularly be inner walls of the holding groove which are circumferentially opposed to one another. The holding groove may particularly be tapered, such that with increased radial distance from the axis of the rack bar, the inner walls of the holding groove have a reduced distance in the circumferential direction with respect to one another. In particular embodiments of the steering system, the rack bar may be slidably positioned in the surrounding guiding member housing, wherein the guiding member housing optionally comprises a support portion for slidably supporting the rack bar. The slidable positioning of the rack bar, and particularly the sliding portion advantageously reduce the friction when actuating the rack bar along the axial direction and improves the guiding performance. The sliding portion may for example include a sliding member which is formed of plastic and which includes a lubricant, a friction reducing finish and / or a friction reducing August 02, 2023 16 coating at a face facing the rack bar. The sliding portion may particularly be disposed on an opposite side of the tapered guiding groove, particularly such that the sliding portion and the tapered guiding groove are disposed diametrically opposed each other at the rack bar. The sliding member may for example include or be sliding bush. The sliding member may particularly be formed to at least partially correspond to the radial outer contour of the rack bar. Thus, the supporting portion and particularly the sliding member advantageously support the rack bar, particularly slidingly support the rack bar, thus providing for an increased working life of the steering system. In exemplary embodiments, the sliding portion and particularly the sliding member may be disposed to cover the tapered guiding groove. The sliding portion and particularly the sliding member may be disposed and formed to cover the tapered guiding groove, such that a radial inner portion of the sliding portion or sliding member is configured to face and / or engage and / or contact the engaging faces of the tapered guiding groove. Furthermore, the sliding portion and particularly the sliding member may be disposed and formed to cover the tapered guiding groove, such that a radial outer portion of the sliding portion or sliding member has two faces opposing each other in the circumferential direction and respectively pointing toward the central axis of the rack bar. In particular embodiments of the steering system, the pre-tensioned engagement member may be held in place in the axial direction with respect to the guiding member housing by means of a washer. In further exemplary embodiments, the steering system and particularly the guiding member may comprise a retaining member, for example a retaining ring, which is August 02, 2023 17 configured to hold the pre-tensioned engagement member in place in the axial direction with respect to the guiding member housing. The retaining member may be screwed, press-fitted or glued into the guiding member housing. The retaining member may clamp the washer between the retaining member and the pre-tensioned engagement member. The washer may include a fail-safe-protrusion substantially corresponding to the tapered guiding groove and protruding into the tapered guiding groove. This way, the fail-safe-protrusion can prevent rotation of the rack bar in case of destruction or loss of the pre-tensioned engagement member. The washer may be rotationally fixed with respect to the guiding member housing by a form-fit connection with the guiding member housing and / or the retaining member. The pre-tensioned engagement member being held in place advantageously allows for securely predetermining the pre-tension for engaging the engaging faces of the tapered guiding groove and / or for securely predetermining the pre-tension for engaging the holding faces of the holding portion. Therefore, the pre-tensioned engagement member being held in place particularly enhances the steering control of the steering system, which is normally affected in case the geometric tolerance and / or force tolerance for the engagement toward the tapered guiding groove and / or guiding member housing is too large, particularly when switching the direction in which the rack bar is actuated. In particular embodiments of the steering system, the guided portion and the guiding member may be in annular engagement. The annular engagement between the guiding member and the guided portion advantageously allows to evenly distribute loads from the rack bar to the guiding member, which accordingly ensures an increased service life of the steering system. In particular embodiments, the annular engagement between the guiding member and the guided portion may include a circumferential coding. This advantageously enhances mechanical surveillance of the rack bar over the August 02, 2023 18 service life of the steering system, and particularly enhances the evaluation of bending or torsional displacements of the rack bar over its service life, for example in order to distinctly detect and evaluate wear of the engagement between the rack bar and the guiding member. In particular embodiments of the steering system, the guiding member and particularly the tapered rack bar engaging portion of the guiding member may axially extend in a range of about 5 mm to about 150 mm, preferably in a range of about 20 mm to about 80 mm. The guiding member and particularly the tapered rack bar engaging portion of the guiding member may axially extend in a range which is different from the above mentioned ranges, as long as it provides the guiding member and particularly the tapered rack bar engaging portion with sufficient strength, particularly with sufficient strength for preventing a circumferential movement of the rack bar over a predetermined life span. The axial extension of the guiding member and particularly of the tapered rack bar engaging portion of the guiding member as defined above advantageously provides for a stiff guidance of the rack bar along the axial direction via the guiding member, advantageously reducing bending stress at the actuator for actuating the rack bar so as to move along the axial direction. The reduced bending stress at the actuator in turn advantageously increases the service life of the steering system. At the same time, the guiding member particularly has a comparatively small weight, which enhances the efficiency of the steering system, thus ensuring an efficient and reliable steering. The guided portion of the rack bar may particularly have an axial extension which corresponds to the general movement of the rack bar in the vehicle width direction in order to pivot a steerable wheel, or to pivot two steerable wheels of an axis of a vehicle. In particular embodiments of the steering system, the rack bar may have an actuated portion at a first longitudinal section of the rack bar and the guided portion at a second longitudinal section of the rack bar, wherein the first longitudinal section and the second longitudinal section of the rack bar are axially spaced apart from one another. August 02, 2023 19 In other words, the first longitudinal section of the rack bar at which the actuator engages and the second longitudinal section of the rack bar at which the guiding member engages may be longitudinally spaced apart from one another. The actuated portion of the rack bar may particularly be a portion which engages with the actuator of the steering system in order to move the rack bar in its axial direction. Providing distinct axially distant portions for guiding the rack bar in the axial direction and for actuating the rack bar to move in the axial direction allows for increasing the efficiency of the actuated movement of the rack bar via the actuator, and for precisely and reliably guiding the rack bar via the guiding member. Moreover, since the rack bar does not have to be connected to a steering column, the length of the rack bar can still be advantageously reduced, particularly providing the steering system with a reduced weight. In further exemplary embodiments, the guided portion may particularly have a radial innermost outer contour which is greater than a radial outermost contour of the rack bar in the front and / or in the rear of the guided portion of the rack bar. In other words, the second longitudinal section of the rack bar at which the guided portion is provided may have a radial innermost outer contour which is greater than a radial outermost contour of the rack bar in the front and / or in the rear of the second longitudinal section of the rack bar. This advantageously facilitates assembling of the rack bar with the guiding member, since the rack bar may for example simply be inserted through the guiding member. In exemplary embodiments, one or more axially limiting parts may be assembled to the guided portion, particularly at respective axial ends of the guided portion. The axially limiting parts may be configured to provide an axial movement stop when touching the guiding member. In particular embodiments of the steering system, the actuator may include a ball screw August 02, 2023 20 to axially move the rack bar. In other exemplary embodiments of the steering system, the actuator may include a rotatable spiral to axially move the rack bar, such as or similar to an internal thread, or a pinion to axially move the rack bar. The actuator may particularly be in engagement with the actuated portion of the rack bar in order to move the rack bar in the axial direction when the actuator is in an actuating state. The actuated portion of the rack bar may particularly include a spiral-shaped portion in accordance with the actuator, such as or similar to an external thread, such that the actuator, by applying a rotational actuation, causes the rack bar to move in the axial direction of the rack bar. The actuator which may particularly be a ball screw advantageously, and particularly owing to the prevented movement of the rack bar in the circumferential (rotational) direction, allows to translate a rotational actuation into a linear or axial movement of the rack bar in particularly space as well as frictional efficient manner. Furthermore, the actuator as defined above, which may particularly be a ball screw, further enhances the axial guidance of the rack bar further to the axial guidance provided by the guiding member. In particular embodiments of the steering system, the actuator may be configured to be electrically controlled to axially move the rack bar in response to a steering movement of a user of the vehicle. In further particular embodiments, the actuator may be configured to be exclusively electrically controlled to axially move the rack bar in response to the steering movement of a user of the vehicle. Electrically controlling the actuator to axially move the rack bar in response to the steering movement of the user of the vehicle August 02, 2023 21 advantageously configures the steering system to be suitable for steer-by-wire steering, such that no steering column is necessary for the steering system, which in turn advantageously reduces the weight of the steering system. The actuator may be powered by a powering unit, particularly an electric powering unit. The powering unit may particularly be configured to receive an input signal initiated by a driver turning the steering wheel of the vehicle. Upon turning the steering wheel of the vehicle, and upon according receipt of the input signal by the electric powering unit, the electric powering unit may be configured to power the actuator which switches into the actuating state and, due to its engagement with the rack bar, moves the rack bar in the axial direction. Without being limited thereto, the rack bar may particularly be powered in a vehicle width direction, so as to effect a pivoting of one or more steered wheels, particularly about a substantially vertical axis of the respective steered wheel. The guiding member being configured to circumferentially surround the rack bar and to limit or prevent the circumferential movement of the rack bar provides for a simple linear guidance of the rack bar which stiffly engages and / or encloses the rack bar. This in turn particularly provides for a reduced bending stress at the actuator of the steering system, which accordingly increases the service life of the steering system. The guiding member which includes the guiding member housing, which is for example fixable to a frame of the vehicle, and the pre-tensioned engagement member is accordingly formed of multiple parts which may respectively be secured to one another and / or pre-tensioned with respect to one another so as to circumferentially surround and slidingly engage with the guided portion of the rack bar, allowing the rack bar to move in the axial direction while limiting or preventing the rack bar from moving in the circumferential direction and the radial direction of the rack bar. Forming the guiding member of multiple parts which are securable to one another and / or which may be pre-tensioned with respect to one another advantageously facilitates the assembly of the guiding member to the guided portion, or in other words facilitates installing the rack bar relative to the guiding member in form-fit manner with August 02, 2023 22 respect to the circumferential direction and the radial direction of the rack bar. According to another aspect, a vehicle to be steer-by-wire steered is provided, the vehicle including: a steering wheel; and a steering system according to the aspect relating to the steering system, wherein the steering wheel is communicatively connected to the actuator. In particular embodiments of the vehicle, the steering wheel is communicatively, particularly electrically, connected to the actuator, and more particularly is mechanically disconnected from the actuator. Thus, the vehicle to be steer-by-wire steered particularly provides for an improved steering support for a vehicle, which allows for steer-by-wire steering the vehicle, such that the driver of the vehicle, owing to the communicatively connected actuator for moving the rack bar, merely needs to apply a comparatively reduced force for turning the steering wheel in order to conveniently steer the vehicle in a desired direction. The vehicle may particularly include a steering control unit which is communicatively connected to the steering wheel. The steering control unit in turn may particularly be communicatively connected to the actuator and / or a powering unit, particularly an electric powering unit, which is configured to power the actuator. The actuator is particularly configured to translate a rotational movement into a linear or axial movement of the rack bar, wherein the guiding member ensures that the linear or axial movement of the rack bar does not include any rotation of the rack bar, which in turn ensures precisely effecting the steered wheels to pivot in accordance with the turning of the steering wheel. The steering control unit may particularly be configured to determine a steering movement or turning of the steering wheel due to a steering or turning of the steering wheel by a driver and / or a computer. In response to the determination of the steering movement or turning of the steering wheel, the steering control unit may be configured to send an input signal reflective of the determined steering movement or turning of August 02, 2023 23 the vehicle to the powering unit to power the actuator of the steering system. The powering unit may be configured to bring the actuator in an actuating state in which the actuator moves the rack bar along the axial direction of the rack bar, in order to pivot the wheels to be steered in accordance with the determined steering movement or turning of the steering wheel. In view of the steer-by-wire steered vehicle as defined above, no steering column connected to the rack bar is necessary. The vehicle not having a steering column for mechanically connecting the steering wheel with the rack bar particularly allows for shortening the rack bar, which in turn advantageously reduces the weight of the steering system of the vehicle, thus providing an efficient and convenient steering support for the driver. These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments. Figure 1a schematically shows a steering system according to the prior art; Figure 1b shows schematic sketch of a steering system according to an embodiment of the present invention; Figure 2a shows a rack bar and an actuator according to an exemplary embodiment of the present invention; Figure 2b shows a cross section of a rack bar according to an exemplary embodiment of the present invention; Figures 3a to 3b show schematic cross sections of a rack bar in engagement with a guiding member according to exemplary embodiments of the August 02, 2023 24 present invention; Figure 3c shows a schematic cross section of a rack bar in engagement with a guiding member according to an exemplary embodiment of the present invention; Figures 4a to 4c show a rack bar in engagement with a pre-tensioned engagement member according to exemplary embodiments of the present invention; Figures 5a to 6c show schematic cross sections and partial cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre-tensioned engagement member according to exemplary embodiments of the present invention; Figures 7a to 7d show schematic cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary embodiments of the present invention; Figures 8a to 8c show schematic cross sections and partial cross sections of a rack bar in engagement with a guiding member according to exemplary embodiments of the present invention; Figures 9a to 9c show a schematic cross section of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary embodiments of the present invention; Figures 10a to 11c show schematic cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary August 02, 2023 25 embodiments of the present invention; Figures 12a to 12b show schematic cross sections of a rack bar in engagement with a guiding member according to exemplary embodiments of the present invention; Figures 13a to 13c show schematic cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary embodiments of the present invention; Figures 14a to 14c show schematic cross sections of a rack bar in engagement with a guiding member according to exemplary embodiments of the present invention; Figures 15a to 15c show schematic cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary embodiments of the present invention; and Figures 16a to 17b show schematic cross sections of a rack bar in engagement with a guiding member and a rack bar in engagement with a pre- tensioned engagement member according to exemplary embodiments of the present invention. Figure 1a schematically shows a steering system 100 according to the prior art. Even though shown with respect to the steering system 100 according to the prior art, some parts of the steering system 100 may also be present in a steering system 1 according to an embodiment of the present invention, as will particularly be emphasized in view of the other figures 1b, 2a, 2b, and 3a to 3f. As shown in Fig. 1a, the steering system 100 according to the prior art particularly August 02, 2023 26 includes a steering wheel 10 to be steered by a user or driver of the vehicle. The steering wheel 10 is connected to the rack bar 20 via the steering column 12, wherein the steering column 12 translates a turning of the steering wheel 10 into a lateral motion of the rack bar 20, such that the steering column 12 powers the rack bar 20 to substantially move left and right in the vehicle width direction W. Owing to the movement of the rack bar 20 in the vehicle width direction W which particularly corresponds to a substantially axial movement or movement along axial direction A of the rack bar 20 back and forth, the respective wheels 14 are pivoted about a substantially vertical direction V of each wheel 14. Figure 1b shows a schematic sketch of a steering system 1 according to an embodiment of the present invention. As shown in Fig.1b, the steering system 1 according to an embodiment of the present invention particularly includes a rack bar 20 which is longitudinally guided, particularly along the axial direction A of the rack bar 20, by a guiding member 30. The guiding member 30 may particularly engages the rack bar 20 at an engaged portion 26 of the rack bar 20, as exemplarily shown in Fig.2a, such that the guiding member 30 limits or prevents a rotational movement of the rack bar 20 about its axis which is also particularly indicated by the axial direction A. The guiding member 30 further particularly limits or prevents a radial movement of the rack bar 20 relative to the guiding member 30 and / or relative to an actuator 40. As further shown in Fig.1b, the steering system 1 particularly includes the actuator 40 which is configured to move the rack bar 20 in the axial direction A of the rack bar 20 in an actuating state of said actuator 40. In particular embodiments, the actuator 40 engages the rack bar 20 at an actuated portion 28 of the rack bar 20, as exemplarily shown in Fig.2a. The actuator 40 may particularly be configured, particularly owing to the prevented rotational movement of the rack bar 20, to translate a rotational actuation at or within the actuator 40 into a linear movement of the rack bar 20. In particular embodiments, and as exemplarily shown in Fig.2a, the actuator 40 may August 02, 2023 27 include or be connected to a powering unit 46 which powers the actuator 40 via a power connector 44. The powering unit 46 may particularly be configured to apply a rotational actuation or rotational motion at the actuator 40 or at a portion of the actuator 40 which faces the rack bar 20 via the power connector 44. The powering unit 46 may particularly be an electric powering unit 46 which is configured to receive an input signal upon turning a steering wheel 10, for example from a steering control unit (not shown). Accordingly, the steering system 1 may particularly include a steering wheel 10 as exemplarily depicted in Fig.1a. However, the steering wheel 10 of the steering system 1, as schematically shown in Fig.1b, is particularly not mechanically connected to the rack bar 20 via a steering column 12. The steering control unit of the steering system 1 may particularly be configured to determine a steering movement or turning of the steering wheel 10, as for example initiated by a driver or user of a vehicle which comprises the steering system 1. In further exemplary embodiments, the steering movement or turning of the steering wheel 10 may also be initiated by a vehicle computer, which may particularly include imaginary initiation on the basis of a steering command issued by the vehicle computer, particularly in the case of an autonomous vehicle. Upon determination of the steering movement or turning of the steering wheel 10, the steering control unit is particularly configured to send an input signal to the powering unit 46, wherein the input signal is particularly reflective of the determined steering movement or turning of the steering wheel 10, for example in that the input signal includes a turning angle and / or an angular displacement of the steering wheel 10 detected by a suitable detector. Upon receipt of the input signal reflective of the determined steering movement or turning of the steering wheel 10, the powering unit 46 is configured to power the actuator 40, particularly via the power connector 44, particularly in a powering direction corresponding to a clockwise or counter-clockwise steering movement or turning of the steering wheel 10. The actuator 40 in turn, which particularly engages an actuated August 02, 2023 28 portion 28 of the rack bar 20 (see Fig.2a), actuates the rack bar 20 via said actuated portion 28 so as to axially move the rack bar 20 substantially in the axial direction A or substantially opposite to the axial direction A, i.e. substantially back or forth in the axial direction A, depending on the determined clockwise or counter-clockwise steering movement or turning of the steering wheel 10. Comparing Fig. 1a to Fig. 1b, wherein the steering system 1 according to Fig. 1b particularly does not require a steering column 12 as connection between the steering wheel 10 and the rack bar 20, the steering system 1 accordingly allows to particularly shorten the rack bar 20 compared to the prior art steering system 100, because no crossing point of the rack bar 20 with respect to a steering column 12 needs to be configured, such that a weight of the steering system 1 can advantageously be reduced. The powering unit 46 may particularly include an electric motor which is configured to power the power connector 44, such as a pulley, in order to apply a rotational actuation or rotational motion at or within the actuator 40. The actuator 40 may particularly include a ball screw 42 (see Fig. 2a), wherein the ball screw 42 is particularly fixed along the axial direction A, for example by securing the ball screw 42 to a housing 50 or to a vehicle body portion. By rotating the axially fixed ball screw 42, the rotation of the ball screw 42 powers the rack bar 20 to move back and forth in the axial direction A. In case a ball screw 42 is used to translate a rotational actuation into an axial movement of the rack bar 20, the rack bar 20 particularly includes a spiral portion, such as or similar to an outer threaded portion. Besides frictional efficiently powering an axial movement of the rack bar 20, the ball screw 42 advantageously further enhances the axial guidance of the rack bar 20, which accordingly provides for a precise steering over an increased service life. Figure 2a shows a rack bar 20 and an actuator 40 according to an exemplary embodiment of the present invention. As shown in Fig.2a, the rack bar 20 particularly includes a guided portion 26 at which August 02, 2023 29 the guiding member 30 (not shown in Fig.2a, but particularly shown in Figs.3a to 17b) engages the rack bar 20. The guided portion 26 of the rack bar 20 particularly includes a tapered guiding groove 22 having two engaging faces 23 opposing each other, particularly opposing each other in the circumferential direction U of the rack bar 20. The tapered guiding groove may at least partially be formed at a radially outer portion of the rack bar 20 and may accordingly particularly be configured to face the surrounding guiding member 30 as shown in Figs.3a to 17b. The tapered guiding groove 22 accordingly is particularly guided by the guiding member 30, which may include one or more pre-tensioned engagement members 36 for at least partially engaging the tapered guiding groove 22.. As shown in Fig.2a, the guided portion 26 particularly longitudinally extends along a predetermined axial length 27 of the rack bar 20, such that the rack bar 20 particularly includes a longitudinally or axially extending guided portion 26 along which an engagement of the guiding member 30 is ensured when moving the rack bar 20 along the axial direction A. Along the axial length 27 of the guided portion 26, the tapered guiding groove 22 may at least partially be constant in a cross section substantially perpendicular to the axial direction A. As further shown in Fig.2a, the rack bar 20 particularly includes an actuated portion 28 which longitudinally extends over a predetermined axial length 29 of the rack bar 20, at which the actuator 40 is configured to engage the rack bar 20, in order to move the rack bar 20 in the axial direction A. The longitudinally or axially extending actuated portion 28 advantageously ensures an engagement of the actuator 40 when moving the rack bar 20 along the axial direction A. Along the axial length 29 of the actuated portion 28, the actuated portion 28 may at least partially have a spiral shape or particularly an outer threaded shape. As shown in Fig.2a, the guided portion 26 is disposed at a first longitudinal section of the rack bar 20 and the actuated portion 28 is disposed at a second longitudinal section of the rack bar 20, wherein the first longitudinal section and the second longitudinal August 02, 2023 30 section may be adjacent to one another or be axially distant from one another. Without being limited to it, but in preferable embodiments as exemplarily shown in Fig.2a, the guided portion 26 and the actuated portion 28 particularly do not interfere with each other but are disposed axially spaced apart at the rack bar 20. This advantageously ensures an efficient and precise guidance of the rack bar 20. However, in case it is intended to further shorten the rack bar 20 and to further reduce the weight of the steering system 1, the guided portion 26 and the actuated portion 28 may at least partially overlap, such that the guided portion 26 for example at least partially extends into the actuated portion 28 or through the actuated portion 28. For example, one or more tapered guiding grooves 22 of the guided portion 26 may at least partially extend into the actuated portion 28. One or more tapered guiding grooves 22 of the guided portion 26 may for example interrupt the spiral shape or outer threaded shape of the actuated portion 28 along a predetermined axial length at which the axial length 27 of the guided portion 26 and the axial length 29 of the actuated portion 29 overlap. As indicated in Fig.2a, by rotating the actuator 40 or the ball screw 42 of the actuator, wherein the actuator 40 is fixed in the axial direction A, the actuated portion 28 which is engaged by the actuator 40 is pushed or powered left or right in accordance with the rotational direction of the actuator 40. The rotational direction of the actuator 40 is particularly dependent on the power as provided by the powering unit 46, which in turn is particularly dependent on the steering movement or turning of the steering wheel 10, i.e. particularly dependent on a clockwise or counter-clockwise turning of the steering wheel 10 as particularly determinable by the steering control unit. In this way, the actuator 40 may particularly be configured to move the rack bar 20 in the axial direction A which may particularly be substantially parallel to or correspond to the vehicle width direction W in order to pivot the wheel(s) 14, which is (are) connected to the rack bar 20. Figure 2b shows a cross section of a rack bar 20 according to an exemplary embodiment of the present invention. The rack bar 20 as shown in Fig.2b particularly August 02, 2023 31 refers to the rack bar 20 as shown in Fig.2a, as indicated by the two arrows 2b at the guided portion 26. The cross section as shown in Fig.2b is particularly taken at the guided portion 26 of the rack bar 20, particularly perpendicular to the axial direction A, i.e. in a plane substantially spanned by the radial direction R and the circumferential direction U of the rack bar 20. As shown in Fig.2b, the rack bar 20 at its guided portion 26 particularly includes the tapered guiding groove 22 which is suitably formed for a form-fit engagement with the guiding member 30, to particularly configure a form-fit engagement in the circumferential direction U and the radial direction R, while allowing a relative axial movement between the guiding member 30 and the rack bar 20. As exemplarily shown in figures 2a and 2b, however without being limited thereto, the guided portion 26 may include at least one tapered guiding groove 22 with which the guiding member 30 may engage, particularly via one or more pre-tensioned engagement members 36. As shown in Fig.2b, the tapered guiding groove 22 particularly has two engaging faces 23 opposing each other in the circumferential direction U of the rack bar 20, wherein the two engaging faces 23 are respectively formed to point toward the central axis AX of the rack bar 20. The tapered guiding groove 22 and its two engaging faces 23 may substantially correspond to the respective guiding grooves 22 and their respective engaging faces 23 as exemplarily shown in Figs.3a to 17b. That is, the tapered guiding groove 22 as exemplarily shown in Figs. 3a to 17b may particularly have two engaging faces 23 opposing each other in the circumferential direction U of the rack bar 20, wherein the two engaging faces 23 are respectively formed to point toward the central axis AX of the rack bar 20. Figures 3a to 3b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30 according to exemplary embodiments of the present invention. August 02, 2023 32 Figure 3a particularly shows a cross-section in a plane which is substantially parallel to the axial direction A or the axis AX of the rack bar 20 and which is substantially parallel to the radial direction R of the rack bar 20. Figure 3b particularly shows a cross-section in a plane which is substantially perpendicular to the axial direction A or the axis AX of the rack bar 20. The rack bar 20 and its engagement as shown in Fig.3b may particularly relate to the same engagement of the rack bar 20 as shown in Fig.3a. As shown in Figs. 3a and 3b, the guiding member 30 particularly includes the pre- tensioned engagement member 36. Even though exemplarily shown with two engagement parts 65, the pre-tensioned engagement member 36 may also include more than two engagement parts 65, as for example shown in Fig.3c. Figure 3c shows a schematic cross section of a rack bar 20 in engagement with a guiding member 30 according to an exemplary embodiment of the present invention. Fig. 3c particularly shows an alternative based on Figs.3a and 3b, but wherein the pre-tensioned engagement member 36 includes more than two engagement parts 65. As long as not mentioned otherwise, the exemplary engagement as shown in Fig.3c may correspond to the ones as shown in Figs.3a and 3b. Figures 4a to 4c show a rack bar 20 in engagement with a pre-tensioned engagement member 36 according to exemplary embodiments of the present invention. Figs.4a to 4c particularly show different states or different types for axially holding the pre-tensioned engagement member 36 and particularly its engagement parts 65 in position, relative to the guiding member housing 31, and particularly relative to the holding portion 32 of the guiding member housing 31. August 02, 2023 33 The exemplary engagements as shown in Figs. 4a to 4c particularly relate to the engagements as shown in Figs.3a and 3b. As long as not mentioned otherwise, the exemplary engagements as shown in Figs.4a to 4c may correspond to the ones as shown in Figs.3a and 3b. As shown in Figs. 3a, 3b and 4a to 4c, the pre-tensioned engagement member 36 particularly includes two engagement parts 65, i.e. particularly exactly two engagement parts 65, which are configured to engage the tapered guiding groove 22 of the rack bar 20, at the guiding portion 26 of the rack bar 20. Accordingly, the two engagement parts 65 particularly form the tapered rack bar engaging portion 64, the tapered rack bar engaging portion 64 being configured to engage the tapered guiding groove 22, and particularly to engage the circumferentially opposed engaging faces 23 with a pre-tension. Each of the two engagement parts 65 may be configured to engage and / or contact one of the engaging faces 23 with a pre-tension. A pre-tensioning means 70 may particularly be at least partially disposed between the two engagement parts 65, or may be disposed between the two engagement parts 65. The pre-tensioning means 70 of the pre-tensioned engagement member 36 may particularly be disposed with respect to the two engagement parts 65, so as to circumferentially bias the two engagement parts 65, i.e. particularly to cause the two engagement parts 65 to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension. As shown in Figs.3a, 3b and 4a to 4c, the guiding member 30 may particularly include a guiding member housing 31. The guiding member housing 31 may include a holding portion 32 for holding the pre-tensioned engagement member 36, particularly for holding the pre-tensioned engagement member 36 in place relative to the guiding August 02, 2023 34 member housing 31, particularly for holding the pre-tensioned engagement member 36 in place relative to the guiding member housing 31 in the circumferential direction U and / or in the axial direction A. The holding portion 32 may particularly include two holding faces 33 opposing each other in the circumferential direction U of the rack bar 20. The holding faces 33 may particularly form limit stops in two opposite directions along the circumferential direction U. In the present embodiment, the holding portion 32 is formed as a holding ring that is press-fitted into the interior of the guiding member housing. Alternatively or in addition, a form-fit connection may be provided to prevent rotation of the holding ring with respect to the rest of the guiding member housing 31. The pre-tensioning means 70 may particularly include an elastomeric member and / or a spring, or other means suitable for causing the engagement parts 65 to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension and / or to engage the holding faces 33 of the holding portion 32 with a pre-tension. As exemplarily shown in Fig.3a but without being limited thereto, the pre-tensioned engagement member 36 may particularly include pre-tensioning means 70 which are disposed at a face of the engagement part 65 which faces a holding face 33 of the two holding faces 33. Therefore, as exemplarily shown in Fig.3a, the housing engaging portion 68 may be formed by the two engaging parts 65 and / or by the two pre-tensioning means 70 which are disposed on faces of the engagement parts 65 facing the two circumferentially opposed holding faces 33. As shown in Figs.3b, 4a and 4c, the guiding member 30 may for example include a fail-safe member 75 in the form of a washer. The fail-safe member 75 may particularly include a fail-safe protrusion formed to engage the tapered guiding groove 22. The fail- safe member 75 may further be configured to engage the guiding member housing 31, particularly to engage the holding faces 33 of the guiding member housing 31. The fail- August 02, 2023 35 safe member 75 may particularly be formed as a one-piece member, and may be configured to hold the pre-tensioned engagement member 36 in place in the axial direction A. In case one of the engagement parts 65 or one of the pre-tensioning means 70 fails, the fail-safe member 75 may be configured to engage the engaging faces 23 at the rack bar 20 and to engage the holding faces 33 of the guiding member housing 31, in order to prevent a rotation of the rack bar 20. In order to provide a simple fail-safe member 75, and in order to prevent further failing parts, the fail-safe member 75 may be provided without pre-tensioning means 70, such that the fail-safe member 75 does not engage the engaging faces 23 and the holding faces 33 with a pre-tension, but rather as a predetermined limit stop. The fail-safe member 75 accordingly particularly allows for securing a minimum of steering control of the steering system, which is affected by the tolerance of the engagement between the fail-safe member 75 and the engaging faces 23 and the holding faces 33, but which is sufficient to steer the vehicle in predetermined conditions to a repair station for example. As shown in Fig.4a, the pre-tensioned engagement member 36 and / or the fail-safe member 75 may be axially held in position relative to the guiding member housing 31 with a retaining member in form of a cover screw 74. The cover screw 74 may for example include an outer thread for screwing the cover screw 74 into an inner thread of the guiding member housing 31, or into an inner thread of a portion which is fixed relative to the guiding member housing 31. In alternative embodiments, the pre-tensioned engagement member 36 and / or the fail- safe member 75 may for example be axially held in position relative to the guiding member housing 31 by a different type of retaining member 72, such as a retaining ring, as for example shown in Fig.5a. As shown in Figs.3b and 4a to 4c, the guiding member 30 may particularly include a August 02, 2023 36 rack bush 76. The rack bush 76 may for example be disposed at one axial end or at both axial ends of the pre-tensioned engagement member 36. The rack bush 76 may particularly be formed to circumferentially surround the rack bar 20. The outer circumference of the rack bush 76 may at least partially be held by the guiding member housing 31. The rack bush 76 may for example be radially held in position by the guiding member housing 31. The rack bush 76 accordingly particularly provides for an improved guidance of the rack bar 20, particularly preventing a skewed positioning of the rack bar 20 in the guiding member housing 31. The guiding member housing 31 and the guiding portion 32 of the guiding member housing 31 may be fixed, particularly radially fixed. The guiding member housing 31 may for example be fixed via one or more fixing members, and / or may be frictionally fixed, and / or be fixed via a form fit (positive fit), The guiding member housing 31 may for example be fixed to a frame of the vehicle or with respect to a frame of the vehicle. As shown in Fig.3c, in comparison to Figs.3a, 3b and 4a to 4c, the pre-tensioned engagement member 36 may include more than two engagement parts 65. The pre-tensioned engagement member 36 may for example include at least four engagement parts 65 which may for example be adjacently disposed in the circumferential direction U of the rack bar 20. In between each adjacent pair of engagement parts 65, a pre-tensioning means 70 may be disposed, wherein the pre- tensioning means 70 are configured to push the engagement parts 65 apart in the circumferential direction U of the rack bar 20. Thus, at least four engagement parts 65 may for example include two or more circumferentially inner engagement parts 65, which are configured to engage the tapered guiding groove 22, and include two or more circumferentially outer August 02, 2023 37 engagement parts 65, which are configured to engage the holding faces 33 of the guiding member housing 31. Meanwhile the accordingly circumferentially inner disposed pre-tensioning means 70 particularly allows for compensating a tolerance of the two circumferentially inner engagement parts 65 relative to the engaging faces 23 of the tapered guiding groove 22, the circumferentially outer disposed pre-tensioning means 70 particularly allow for compensating a tolerance of the circumferentially stacked engagement parts 65 relative to the holding faces 33 of the holding portion 32 of the guiding member housing 31. Further exemplary embodiments are shown in Figs.5a to 17b. Those embodiments particularly focus on a different pre-tensioning direction, and / or on a different engagement of the pre-tensioned engagement member 36 relative to the tapered guiding groove 22 of the rack bar 20 and / or relative to the guiding portion 32 of the guiding member housing 31. If not mentioned otherwise, the exemplary embodiments as shown in Figs.5a to 17b may correspond to the ones as shown in Figs.3a to 4c, particularly with respect to the rack bush 76, which may for example be replaced or supplemented with one or more guiding members 60, with respect to the fail-safe member 75, with respect to the cover screw 74, which may for example be replaced or supplemented with one or more guiding members 60 such as retaining rings, and / or with respect to the fixture of the guiding member housing 31. As shown in the exemplary embodiments as shown in Figs.3a to 17b, the rack bar 20 may include one or more tapered guiding grooves 22, such that even though some embodiments depict only one or more than one tapered guiding groove 22 to be engaged, it is understood that the respective embodiment may accordingly be adapted to include a rack bar 20 with more than one tapered guiding groove 22 or with only one tapered guiding groove 22. Figure 5a schematically shows a partial cross section of a rack bar 20 in engagement with a guiding member 30, Figs.5b, 5c and 6a show schematic cross sections a rack August 02, 2023 38 bar 20 in engagement with a guiding member 30, and Figs.6b and 6c show a rack bar 20 in engagement with a pre-tensioned engagement member 36 respectively according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs.5b 5c, 6a, 6b and 6c may particularly correspond to the exemplary embodiment as shown in Fig.5a. As shown in Figs. 5a to 6c, the pre-tensioned engagement member 36 may for example include at least four or four engagement parts 65. The engagement parts 65 may particularly be adjacently disposed relative to one another in the axial direction A of the rack bar 20. The pre-tensioned engagement member 36 may particularly includes two tooth washers which respectively have a tapered rack bar engaging portion 64, also referred to as a first pair of tooth washers, and include two tooth washers which respectively have a housing portion 68, also referred to as a second pair of tooth washers. The tooth washers may be adjacently disposed relative to one another in the axial direction A so as to contact one another. The tooth washers may include inclined teeth at least at a side which faces the axially adjacent tooth washer. As shown in Figs.5a to 6c, the pre-tensioned engagement member 36 may include one or more pre-tensioning means 70. The pre-tensioning means 70 may for example be disposed at one or both axial ends of the pre-tensioned engagement member 36. The pre-tensioning means 70 may particularly be configured to bias the tooth washers in the axial direction A, particularly such that the tooth washers of the first pair of tooth washers force each other in opposite directions along the circumferential direction U, and such that the tooth washers of the second pair of tooth washers force each other in opposite directions along the circumferential direction U. Based on the pre-tensioning means 70 biasing the tooth washers in the axial direction August 02, 2023 39 A toward each other and the inclined teeth of the tooth washers of the first and second pairs of tooth washers, the engaging faces 23 of the tapered guiding groove(s) 22 and the holding faces 33 of the holding portion(s) 32 may respectively engaged with a pre- tension. Specifically, based on the pre-tensioning means 70 biasing the tooth washers in the axial direction A toward each other and the inclined teeth of the tooth washers of the first and second pairs of tooth washers, the axially adjacent tooth washers, particularly of the first and second pair of tooth washers, may engage with each other via their respective inclined teeth, such that a rotational force is exerted in opposite directions along the circumferential direction U of the rack bar 20. onto the tooth washers which face and particularly contact each other. As shown in Figs.5a, 5b, 6b, 6c, the guiding member 30 may particularly include one or more washers 38 for pre-defining an axial biasing force of the pre-tensioning means 70 toward the tooth washers, and for holding the pre-tensioned engagement member 36 in place in the axial direction A. Figures 7a and 7b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30, and Figs.7c and 7d show a rack bar 20 in engagement with a pre-tensioned engagement member 36, respectively according to exemplary embodiments of the present invention; Figures 7a to 7d may particularly relate to the same embodiment. As shown in Figs. 7a to 7d, the pre-tensioned engagement member 36 may for example include a radial inner engagement part 65 which forms a rack bar engaging portion 64 engaging the tapered guiding groove 22, and a radial outer engagement part 65 which forms a housing engaging portion 68 engaging the holding portion 32, wherein the holding portion 32 may particularly be formed as a tapered holding groove 35. August 02, 2023 40 The radial inner engagement part 65 and the radial outer engagement part 65 may particularly be disposed to face each other in the radial direction R of the rack bar 20. In others words, the radial inner engagement part 65 and the radial outer engagement part 65 may be radially adjacently disposed relative to one another. As shown in Figs.7a to 7d, between the radial inner engagement part 65 and the radial outer engagement part 65, a pair of further engagement parts 65 may be at least partially encased by the radial inner engagement part 65 and the radial outer engagement part 65. Between the at least partially encased further engagement parts 65, a pre-tensioning means 70 may be disposed, pushing the at least partially encased further engagement parts 65 apart one another, particularly pushing the at least partially encased further engagement parts 65 apart in the axial direction A of the rack bar 20. The radial inner engagement part 65 and the radial outer engagement part 65 may respectively have inclined inner walls. The inner walls of the radial inner engagement part 65 and the radial outer engagement part 65 are particularly inclined in a manner, such that the pair of further engagement parts 65 which are pushed apart one another respectively contact the inclined inner walls and force the radial inner engagement part 65 and the radial outer engagement part 65 apart one another in the radial direction R of the rack bar 20. Thus, the holding portion 32 and particularly the holding faces 33 of the tapered holding groove 35 are engaged by the radial outer engagement part 65 with a pre-tension, and the engaging faces 23 of the tapered guiding groove 22 are engaged by the radial inner engagement part 65 with a pre-tension. The at least partially encased engagement parts 65 may for example be ball-shaped or elliptically shaped in order to reliably force the radial inner engagement part 65 and the radial outer engagement part 65 apart one another in the radial direction R of the rack bar 20. August 02, 2023 41 As shown in Fig. 7b, the guiding member 30 may particularly include one or more washers 38 for securing the radial forcing apart of the radial inner engagement part 65 and the radial outer engagement part 65 into the respective grooves 22, 35. Figures 8a and 8b show schematic cross sections and Fig.8c shows a partial cross sections of a rack bar 20 in engagement with a guiding member 30 according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs. 8a, 8b and 8c may particularly correspond to the same exemplary embodiment. As shown in Figs. 8a to 8c, the pre-tensioned engagement member 36 may for example include one or more engagement parts 65, or only one engagement part 65. The one or more engagement parts 65 may particularly integrally form or have a tapered rack bar engaging portion 64.and a housing engaging portion 68. The one or more engagement parts 65 may particularly be substantially plate-shaped or disc-shaped. The one or more engagement parts 65 may particularly include a radial protrusion, protruding toward the axis AX of the rack bar 20 and forming the tapered rack bar engaging portion 64. The plate-shape or disc-shape of the one or more engagement parts 65, and particularly its distal ends, may particularly form the housing engaging portion 68. As shown in Figs.8a and 8b, the pre-tensioning means 70 may particularly be disposed opposite to the tapered guiding groove 22 and the engagement part 65 relative to the rack bar 20. Thus, the pre-tensioning means 70 may particularly be configured to force the rack bar 20 toward the engagement part 65, in order to engage the engaging faces 23 and the holding faces 33 with a pre-tension. As shown in Figs.8a to 8c, the guiding member housing 31 may include or at least August 02, 2023 42 partially house a supporting portion 78, wherein the supporting portion 78 and / or a sliding member 60 disposed between the supporting portion 78 and the rack bar 20 is configured to face and / or contact the rack bar 20, particularly to slidingly contact the rack bar 20. The guiding member 30 may particularly include an adjustment member 82. The adjustment member 82 may for example include a thread to be threadably adjustable positioned in the guiding member housing 31. The supporting portion 78 may particularly be positioned between the adjustment member 82 and the rack bar 20, particularly in a substantial radial direction R of the rack bar 20. The pre-tensioning means 70 may at least partially be disposed between the adjustment member 82 and the supporting portion 78. By threadably adjusting the position of the adjustment member 82 in the guiding member housing 31, a pre-tension of the supporting portion 78 toward the rack bar 20 may be adjusted, and a pre-tension with which the rack bar engaging portion 64 of the engagement part 65 engages the engaging faces 23 and with which the housing engaging portion 68 of the engagement part 65 engages the holding faces 33 may be predefined. Figure 9a shows a schematic cross section of a rack bar 20 in engagement with a guiding member 30, and Figs.9b and 9c show a rack bar 20 in engagement with a pre- tensioned engagement member 36, respectively according to exemplary embodiments of the present invention; The exemplary embodiments as respectively shown in Figs. 9a, 9b and 9c may particularly correspond to the same exemplary embodiment. As shown in Figs. 9a to 9c, the pre-tensioned engagement member 36 may for example include six or more engagement parts 65 or six engagement parts 65, particularly for engaging two tapered guiding grooves 22 and two holding portions 32. The pre-tensioned engagement member 36 may particularly include two separate August 02, 2023 43 engagement parts 65 for engaging one tapered guiding groove 22, wherein each of the two engagement parts 65 for engaging one tapered guiding groove 22 is configured to engage one engaging face 23 of the tapered guiding groove 22 with a pre-tension. The two separate engagement parts 65 for engaging one tapered guiding groove 22 may particularly face each other and / or be adjacently disposed one another in the circumferential direction U. The pre-tensioned engagement member 36 may particularly include two separate engagement parts 65 for engaging one tapered holding groove 35, wherein each of the two engagement parts 65 for engaging one tapered holding groove 35 is configured to engage holding face 33 of the tapered holding groove 35 with a pre-tension. The two separate engagement parts 65 for engaging one tapered holding groove 35 may particularly face each other and / or be adjacently disposed one another in the circumferential direction U. Without being limited thereto, one of the two separate engagement parts 65 for engaging one tapered guiding groove 22 may integrally form one of the two separate engagement parts 65 for engaging one tapered holding groove 35. The engagement part 65 for integrally engaging one tapered guiding groove 22 and one tapered guiding groove 35 may particularly be configured to integrally engage one tapered guiding groove 22 and one tapered holding groove 35 which face each other in the radial direction R of the rack bar 20. The engagement part 65 for integrally engaging one tapered guiding groove 22 and one tapered guiding groove 35 may be configured to partially circumferentially extend around the rack bar 20, for example to circumferentially extend around about half of the rack bar 20, but particularly without engaging more than one tapered guiding groove 22 and / or more than one tapered holding groove 35. This engagement part 65 may in the following also be referred to as arc-shaped engagement part 65. The separate engagement part 65 which is configured to only engage the tapered guiding groove 22 may also be referred to as radial inner engagement part 65. The separate August 02, 2023 44 engagement part 65 which is configured to only engage the holding portion 32 and particularly the tapered holding groove 35 may also be referred to as radial outer engagement part 65, The radial inner engagement part 65 accordingly particularly includes or has a rack bar engaging portion 64. The radial outer engagement part 65 accordingly particularly includes or has a housing engaging portion 68. The arc-shaped engagement part 65 particularly includes or has a rack bar engaging portion 64 and a housing engaging portion 68. The radial inner engagement part 65 and the radial outer engagement part 65 may particularly be configured to face each other in the radial direction R of the rack bar 20. Between the radial inner engagement part 65 and the radial outer engagement part 65 a pre-tensioning means 70 may be disposed. The pre-tensioning means 70 is particularly configured to push the radial inner engagement part 65 and the radial outer engagement part 65 apart, particularly in the radial direction R of the rack bar 20. The radial inner engagement part 65 and the arc-shaped engagement part 65 may particularly be configured to face each other in the circumferential direction U of the rack bar 20. The radial outer engagement part 65 and the arc-shaped engagement part 65 may particularly be configured to face each other in the circumferential direction U of the rack bar 20. The pre-tensioning means 70 is accordingly particularly configured to push the radial inner engagement part 65 and its rack bar engaging portion 64 into the tapered guiding groove 22, and to push the radial outer engagement part 65 and its housing engaging portion 68 into the tapered holding groove 35. By pushing the radial inner engagement part 65 into the tapered guiding groove 22 and the radial outer engagement part 65 into the tapered holding groove 35, the circumferentially facing arc-shaped August 02, 2023 45 engagement part 65 may particularly be pushed toward an engaging face 23 of the tapered guiding groove 22 and a holding face 33 of the tapered holding groove 35. Thus, the pre-tensioning means 70 may particularly be configured to cause the radial inner engagement part 65 and the arc-shaped engagement part 65 to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension, and to cause the radial outer engagement part 65 and the arc-shaped engagement part 65 to engage the holding faces 33 of the holding portion 32, and particularly the tapered holding groove 35 of the holding portion 32, with a pre-tension. Meanwhile the engagement has been demonstrated with particular regards to one tapered guiding groove 22 and one holding portion 32, it is understood that the same applies for the engagement of the diametrically opposed tapered guiding groove 22 and holding portion 32, as particularly shown in Figs.9a to 9c. As shown in Figs.9a to 9c but without being limited thereto, the guiding member 30 may particularly include a sliding member 60 which closely surrounds the rack bar 20, particularly at the guided portion 26, and which includes one or more grooves corresponding to the one or more tapered guiding grooves 22 of the rack bar 20. The one or more grooves of the sliding member 60 corresponding to the one or more tapered guiding grooves 22 of the rack bar 20 may correspondingly engaged by the engagement parts 65 and particularly by the rack bar engaging portions 64 of the engagement parts 65. Figures 10a to 10c show a rack bar 20 in engagement with a pre-tensioned engagement member 36, and Figs.11a and 11b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30, respectively according to exemplary embodiments of the present invention; The exemplary embodiments as respectively shown in Figs. 10a, 10b, 10c, 11a and 11b may particularly correspond to the same exemplary embodiment. August 02, 2023 46 As shown in Figs. 10a to 11b, the pre-tensioned engagement member 36 may for example include one or more engagement parts 65, or only one engagement part 65, particularly for engaging two tapered guiding grooves 22 and two holding portions 32. The holding portions 32 may particularly be respectively formed as a tapered holding groove 35. For each tapered guiding groove 22 of the rack bar 20, the engagement part 65 may include a radial inward protrusion forming a rack bar engaging portion 64. For each holding portion 32 of the guiding member housing 31, the engagement part 65 may include a radial outward protrusion forming a housing engaging portion 68. The radial inward protrusion forming the rack bar engaging portion 64 may for example be disposed about at the middle of the engagement part 65 in the axial direction A. The radial inward protrusion forming the rack bar engaging portion 64 may for example be disposed in between two sliding members 60 in the axial direction A of the rack bar. Without being limited thereto, the engagement part 65 may particularly have a substantially circular or cylindrical shape. Furthermore, the guiding member 30 may particularly include a sliding member 60 or two sliding members 60. In case of two sliding members 60, said two sliding members 60 may be disposed axially distant from one another. The sliding member(s) 60 may be substantially circular or cylindrically shaped, particularly corresponding to the radial outer face of the rack bar 20 at the guided portion 26. At an axial end of the sliding member(s) 60 which faces the engagement part 65, particularly which faces the rack bar engaging portion 64 of the engagement part 65,, the sliding member(s) 60 may have a tapering. The tapering may have a reduced wall thickness towards the axial end of the sliding member 60 which faces the engagement part 65. August 02, 2023 47 The pre-tensioned engagement member 36 may particularly include one or two pre- tensioning means 70 which are disposed at axial ends of the engagement part(s) 65 and the sliding member(s) 60, so as to push the sliding member(s) 60 toward the radial inward protrusion of the engagement member(s) 65, i.e. toward the rack bar engaging portion 64 of the engagement member(s) 65. By axially pushing the sliding member(s) 60, particularly with the tapering toward the radial inward protrusion of the engagement part 65, the pre-tensioning means 70 cause(s) the sliding member 60 to engage the engaging faces 23 of the tapered holding groove 22 with a pre-tension, and to the engagement part(s) 65 to engage the holding faces 33 of the holding portion 32, particularly of the holding faces 33 of the holding groove 35, with a pre-tension. Figures 12a to 12b show schematic cross sections of a rack bar 20 in engagement with a guiding member 36 according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs. 12a and 12b may particularly correspond to the same exemplary embodiment. As shown in Figs.12a and 12b, the pre-tensioned engagement member 36 may for example include two or more engagement parts 65, or only two engagement parts 65, particularly for engaging a tapered guiding grooves 22 and a holding portion 32. The pre-tensioned engagement member 36 may particularly include a radial inner engagement part 65 which engages the tapered guiding groove 22 of the rack bar 20, and which particularly further engages the holding portion 32 of the guiding member housing 31. The guiding member 30 may particularly include an adjustment member 82. The adjustment member 82 may for example include or be a pin, particularly a threaded August 02, 2023 48 pin. The threaded pin may particularly be threadably adjustable, particularly from outside of the guiding member housing 31. The threaded pin may particularly be threadably mounted to the guiding member housing 31, and may particularly be adjustable with respect to its lengthwise extension from the guiding member housing 31. The direction of the lengthwise extension of the adjustment member 82 may particularly be inclined with respect to the axial direction A of the rack bar 20, particularly so as to cross the axial direction A in a side view of the rack bar 20 as shown in Figs.12a and 12b. The pre-tensioned engagement member 36 may particularly include an intermediary engagement part 65 which on its radial inner face faces and / or contacts the radial inner engagement part 65 and which on its radial outer face faces and / or contacts the adjustment member 82. The pre-tensioned engagement member 36 may particularly include a pre-tensioning means 70 which is disposed at an axial end of the radial inner engagement part 65, particularly at an axial end of the radial inner engagement part 65 which is opposite to an axial end of the radial inner engagement part 65 which faces the adjustment member 82. The pre-tensioning means 70 may particularly be fixed to the guiding member housing 31. The pre-tensioning means 70 may particularly be at least partially disposed in a cavity of the guiding member housing 31. The intermediary engagement part 65 may particularly be trapped or clamped between the radial inner engagement part 65 and the adjustment member 82. The intermediary engagement part 65 and the radial inner engagement part 65 may particularly have correspondingly inclined faces facing each other. The inclination of the inclined face of the radial inner engagement part 65 may particularly be such that August 02, 2023 49 a thickness of the radial inner engagement part 65 in the radial direction R reduces in a direction which is parallel to the axial direction A and facing away from the pre- tensioning means 70. The pre-tensioning means 70 may particularly push the radial inner engagement part 65 toward the intermediary engagement part 65. Based on the inclined faces of the radial inner engagement part 65 and the intermediary engagement part 65, wherein an axial movement of the intermediary engagement part 65 is particularly blocked by the adjustment member 82, the radial inner engagement part 65 engages the engaging faces 23 of the tapered guiding groove 22 and optionally also the holding faces 33 of the guiding member housing 31 with a pre-tension. In other exemplary embodiments, the intermediary engagement part 65 may engage the holding faces 33 of the guiding member housing 31 with a pre-tension. Figures 13a and 13b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30, and Fig.13c shows a rack bar 20 in engagement with a pre-tensioned engagement member 36, respectively according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs. 13a, 13b and 13c may particularly correspond to the same exemplary embodiment. As shown in Figs. 13a to 13c, the pre-tensioned engagement member 36 may for example include one engagement part 65 for each tapered guiding groove 22, wherein the engagement part 65 particularly engages the tapered guiding grooves 22 and a holding portion 32, wherein the tapered guiding groove 22 and the holding portion 32 may face each other in the radial direction R. As shown in Figs.13a to 13c, the guiding member 30 may include a support portion 78 for each tapered guiding groove 22, wherein the support portion 78 may particularly be biased in the radial direction R toward the engagement part 65 by an adjustment member 82, wherein radial outer pre-tensioning means 70 may be disposed between August 02, 2023 50 the adjustment member 82 and the support portion 78. The adjustment member 82 may particularly be threadably mounted to the guiding member housing 31 in order to adjust a pre-tension toward the support portion 78. The holding portion 32 may particularly be disposed in a cavity of the support portion 78, wherein a radial inner pre-tensioning means 70 may be displaced in said cavity. Based on the radial inner and radial outer pre-tensioning means 70 and the adjustment member 82, which may be threadably adjusted relative to the guiding member housing 31 to increase or lower the pre-tension which the radial inner and radial outer pre- tensioning means 70 provide, the engagement part 65 engages the tapered guiding groove 22 as well as the holding portion 32 and their respective faces with a pre- tension. As shown in Figs.13a to 13c, the guiding member 30 may particularly include two pre- tensioned engagement members 36. Without being limited thereto, the two pre- tensioned engagement members 36 may particularly be disposed on diametrically opposed sides of the rack bar 20. Figures 14a to 14c show schematic cross sections of a rack bar 20 in engagement with a guiding member 30 according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs. 14a, 14b and 14c may particularly correspond to the same exemplary embodiment. As shown in Figs. 14a to 14c, the pre-tensioned engagement member 36 may for example include three engagement parts 65, particularly three substantially circular engagement parts 65, wherein the three substantially circular engagement parts 65 may be adjacently disposed in the axial direction A of the rack bar 20. The pre-tensioned engagement member 36 may include an axial intermediary engagement part 65 and two axial outer engagement parts 65 between which the axial August 02, 2023 51 intermediary engagement part 65 is disposed in the axial direction A. The axial intermediary engagement part 65 may particularly include one rack bar engaging portion 64 for each tapered guiding groove 22 of the rack bar 20. Each axial outer engagement part 65 may particularly include one housing engaging portion 68 for engaging a holding portion 32 of the guiding member housing 31. The axial intermediary engagement part 65 may have an inclined face at each of its axial end at which at faces one of the two axial outer engagement parts 65. The inclined face may particularly be formed so as to have a reduced thickness in the radial direction R toward its axial distal end. Each of the two axial outer engagement parts 65 may have a corresponding inclined face corresponding to the respective inclined face of the axial intermediary engagement part 65 which the respective axial outer engagement part 65 faces. The pre-tensioned engagement member 36 may include one or more pre-tensioning means 70 which may particularly be disposed at axial ends of the three engagement parts 65. The guiding member 30 may particularly include one or more retaining members 72, such as retaining rings for example, particularly for holding the pre-tensioned engagement member 36 axially in position relative to the guiding member housing 31. The guiding member 30 may optionally further include one or more washers 38 for predefining a pushing force of the one or more pre-tensioning means 70 in the axial direction A. The one or more washers 38 may particularly be disposed axially between one of the engagement parts 65 and a retaining member 83 or between one of the engagement parts 65 and an axial support portion of the guiding member housing 31. Based on the pre-tensioning means 70 and the corresponding inclined faces of the three engagement parts 65, the axial intermediary engagement part 65 is pushed radially inwards so as to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension, and the two outer axial engagement parts 65 are respectively August 02, 2023 52 pushed radially outwards so as to engage the holding faces 33 of the holding portion(s) 22 with a pre-tension. Figures 15a and 15b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30, and Fig.15c shows a rack bar 20 in engagement with a pre-tensioned engagement member 36, respectively according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs.15a, 15b and 15c may particularly correspond to the same exemplary embodiment. The exemplary embodiment as shown in Figs.15a to 15c is particularly similar to the one as discussed with respect to Figs.14a to 14c, such that in the following, merely differences with respect to the embodiment as shown in Figs. 14a to 14c shall be discussed. As shown in Figs. 15a to 15c, the axial intermediary engagement part 65, and accordingly particularly its inclined faces at its axial ends, may have a substantially spherical shape, particularly at its radial outer face, which particularly allows for compensating an angular misalignment. The axial outer engagement parts 65 may accordingly have corresponding spherical inclined faces facing the axial intermediary engagement part 65. The axial intermediary engagement part 65, further to having a rack bar engaging portion 64, particularly at a radial inner side of the axial intermediary engagement part 65, may particularly have a housing engaging portion 68 engaging the holding portion 32 of the guiding member housing 31, particularly at a radial outer side of the axial intermediary engagement part 65. As furthermore shown in Figs.15a and 15b, the axial intermediary engagement part 65 may particularly have one or more grooves on a radial inner face, wherein in each August 02, 2023 53 groove on the radial inner face, a pre-tensioning member 70 may be disposed. Optionally, further a further engagement part 65 may be disposed in each groove on the radial inner face, such that the pre-tensioning member(s) 70 and / or the further engagement part(s) 65 as disposed in the one or more grooves may engage the tapered guiding groove 22. Based on the pre-tensioning means 70 as disposed in the one or more grooves on the radial inner face of the intermediary engagement part 65, the pre-tensioning means 70 disposed at axial ends of the three engagement parts 65 and the corresponding inclined faces of the three engagement parts 65, the housing engaging portion 68 of the axial intermediary engagement part 65 is pushed radially outwards so as to engage the holding faces 33 of the holding portion 22 with a pre-tension, and the pre-tensioning means 70 which are optionally disposed with further engagement parts 65 in grooves on the radial inner face of the axial intermediary engagement part 65 are pushed radially inwards so as to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension. As shown in Figs.15a and 15b but without being limited thereto, the guiding member 30 may particularly include a sliding member 60 which closely surrounds the rack bar 20, particularly at the guided portion 26, and which includes one or more grooves corresponding to the one or more tapered guiding grooves 22 of the rack bar 20. The one or more grooves of the sliding member 60 corresponding to the one or more tapered guiding grooves 22 of the rack bar 20 may correspondingly be engaged by the axial intermediary engagement part 65 and particularly by the rack bar engaging portions 64 of the axial intermediary engagement part 65. Figures 16b to 17b show schematic cross sections of a rack bar 20 in engagement with a guiding member 30, and Fig.16a shows a rack bar 20 in engagement with a pre-tensioned engagement member 36, respectively according to exemplary embodiments of the present invention. The exemplary embodiments as respectively shown in Figs. 16a, 16b, 17a and 17b August 02, 2023 54 may particularly correspond to the same exemplary embodiment. As shown in Figs.16a to 17b, the rack bar engaging portion 64, the housing engaging portion 68 and the pre-tensioning means 70 may be formed integrally. That is, the engagement part 65 as shown in Figs.16a to 17b particularly has a housing engaging portion 68 engaging the holding portion 32 of the guiding member housing 31, a rack bar engaging portion 64 engaging the tapered guiding groove 22 and pre-tensioning means 70 causing the housing engaging portion 68 to engage the holding faces 33 of the holding portion 32 with a pre-tension and causing the rack bar engaging portion 64 to engage the engaging faces 23 of the tapered guiding groove 22 with a pre-tension. The engagement part 65 may be formed in a bridge-shape, wherein the radial inner portion(s) of the bridge engage the tapered guiding groove 22, and wherein the radial outer portion(s) of the bridge engage the holding portion 32. The guiding member 30 may include one or more washers 38 and one or more retaining members 82 for preadjusting the axial extension of the engagement part 65 along the axial direction A, in order to particularly bend the legs of the bridge between the housing engaging portion(s)68 and the rack bar engaging portion(s) 64. Based on the preadjusted axial extension of the bridge-shaped engagement part 65, the integrally formed engagement part 65 engages the holding faces 33 with a pre- tension and the engaging faces 23 with a pre-tension. List of Reference Numerals 1 steering system 10 steering wheel 12 steering column 14 wheels 20 rack bar 22 tapered guiding groove August 02, 2023 55 23 engaging faces (of the tapered guiding groove) 26 guided portion 27 axial length (of the guided portion) 28 actuated portion 29 axial length (of the actuated portion) 30 guiding member 31 guiding member housing 32 holding portion 33 holding face (of the holding portion) 35 (tapered) holding groove 36 pre-tensioned engagement member 38 washer 40 actuator 42 ball screw 44 power connector 46 powering unit 50 housing 60 sliding member 64 (tapered) rack bar engaging portion 65 engagement part 68 housing engaging portion 70 pre-tensioning means 72 retaining member 74 cover screw 75 fail-safe member 76 rack bush 78 support portion (of the guiding member housing) 82 adjustment member 100 steering system A axial direction AX axis F driving direction August 02, 2023 56 R radial direction U circumferential direction V vertical direction W vehicle width direction

Claims

August 02, 2023 57 Applicant: NSK Europe Ltd. "LINEAR GUIDING FUNCTION FOR SPINDLES" Our Ref.: N 5374WO - asc / tha Claims 1. Steering system (1) for steer-by-wire steering of a vehicle, the system (1) comprising: - a rack bar (20) for displacing steered wheels (14) of the vehicle; - an actuator (40) configured to move the rack bar (20) in an axial direction (A) of the rack bar (20); and - a guiding member (30) for guiding the rack bar (20), -- wherein the guiding member (30) is configured to circumferentially surround and slidingly engage a guided portion (26) of the rack bar (20) so as to allow the rack bar (20) to move in the axial direction (A) while preventing the rack bar (20) to move in a circumferential direction (U) and a radial direction (R) of the rack bar (20); -- wherein the guided portion (26) of the rack bar (20) comprises a tapered guiding groove (22) having two engaging faces (23) opposing each other in the circumferential direction (U) of the rack bar (20); -- wherein the guiding member (30) comprises: a guiding member housing (31), and a pre-tensioned engagement member (36) arranged in the guiding member housing (31) and having a tapered rack bar engaging portion (64), a housing engaging portion (68) and a pre-tensioning means (70), wherein the guiding member housing (31) has a holding portion (32) for holding the pre-tensioned engagement member (36), the holding portion (32) including two holding faces (33) opposing each other in the circumferential direction (U) of the rack bar (20), wherein the pre-tensioning means (70) is configured to cause the tapered rack bar engaging portion (64) to engage the engaging faces (23) of the tapered guiding groove (22) with a pre-tension, and to cause the housing engaging portion (68) to engage the holding faces (33) with a pre-tension, andAugust 02, 2023 58 wherein the two engaging faces (23) are respectively formed to point toward the central axis (AX) of the rack bar (20).

2. Steering system (1) according to claim 1, wherein the pre-tensioned engagement member (36) comprises at least two engagement parts (65), wherein the pre- tensioning means (70) is configured to push the engagement parts (65) apart in the circumferential direction (U) and / or the radial direction (R), and / or to apply a rotating force in opposite rotation directions to the engagement parts (65).

3. Steering system (1) according to claim 2, wherein the tapered rack bar engaging portion (64) is formed by at least two of the engagement parts (65).

4. Steering system (1) according to claim 2 or 3, wherein the housing engaging portion (68) is formed by at least two of the engagement parts (65).

5. Steering system (1) according to claim 1, wherein the rack bar engaging portion (64), the housing engaging portion (68) and the pre-tensioning means (70) are formed integrally.

6. Steering system (1) according to any one of the preceding claims, wherein the pre-tensioning means (70) comprises a rubber spring, wherein the rubber spring is optionally molded onto a portion of the pre-tensioned engagement member (36).

7. Steering system (1) according to any one of the preceding claims, wherein the holding portion (32) of the guiding member housing (31) comprises a tapered holding groove (35), the two holding faces (33) being formed by the inner walls of the holding groove (35).

8. Steering system (1) according to any one of the preceding claims, wherein the rack bar (20) is slidably positioned in the surrounding guiding member housing (31), wherein the guiding member housing (31) optionally comprises a support portion (78) for slidably supporting the rack bar (2).August 02, 2023 59 9. Steering system (1) according to any one of the preceding claims, wherein the pre-tensioned engagement member (36) is held in place in the axial direction (A) with respect to the guiding member housing (31) by means of a washer (38).

10. Steering system (1) according to any one of the preceding claims, wherein the actuator (40) includes a ball screw to axially move the rack bar (20).

11. Steering system (1) according to any one of the preceding claims, wherein the actuator (40) is configured to be electrically controlled to axially move the rack bar (20) in response to a steering movement of a user of the vehicle.

12. Vehicle to be steer-by-wire steered, the vehicle including: - a steering wheel (10); and - a steering system (1) according to any one of the claims 1 to 11, -- wherein the steering wheel (10) is communicatively connected to the actuator (40).

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