Retractable steering system for a vehicle and method for controlling the same

Abstract

Retractable steering system for a vehicle, the retractable steering system comprising: a steering tube (14) connected to a steering wheel (10) via a steering spindle (12), a steering column housing (16) mounted on a crash pad (100), wherein the steering tube (14) is extendably inserted into the steering column housing (16), an electric motor (20) mounted on an outer circumference of the steering column housing (16), a lead screw (22) which is fixedly connected to an output shaft of the electric motor (20), a lead nut (24) into which the lead screw (22) is rotatably inserted, a retraction holder (30) which is attached to the guide nut (24), a gear train (40) mounted on the retraction bracket (30), the steering tube (14) and the steering column housing (16) and configured to form a travel path of the steering tube (14) that is longer than a travel path of the guide nut (24) and the retraction bracket (30), and a control device (60) electrically connected to the electric motor (20) and configured to control an operation of an electric motor control unit (62) electrically connected to the electric motor (20) and to control an operation of the electric motor (20) according to each driving mode, wherein the gear train (40) comprises: a movable rack (42) mounted on an outer surface of the steering tube (14), a stationary rack (44) mounted on an inner surface of the steering column housing (16), and a rotatable gear (46) rotatably provided on the retraction holder (30) connected to the guide nut (24) and meshing with the movable rack (42) and the fixed rack (44).

Description

[0001] The invention relates to a retractable steering system for a vehicle, and more particularly to a retractable steering system for a vehicle configured to receive a steering wheel, a steering shaft, a cover, and the like in a crash pad to maximize the space utilization of an interior of an autonomous vehicle, and a method for controlling the same.

[0002] Generally, a steering wheel used for a driver to steer a vehicle is mounted on a crash pad located in front of a driver's seat of the vehicle, a steering shaft is connected to the steering wheel, and a steering tube is coupled to an outer diameter portion of the steering shaft.

[0003] In addition, a steering column housing is tiltably mounted on the crash pad, and the steering spindle and the steering tube are retractably inserted and arranged in the steering column housing.

[0004] Therefore, by tilting the steering column housing in an up / down direction, the vertical angle of the steering wheel can be adjusted to a level desired by the driver. By inserting the steering shaft and steering tube into or retracting the steering column housing, the forward / backward length of the steering wheel can be adjusted to a level desired by the driver.

[0005] However, there is a problem that the space utilization of a driver's seat deteriorates due to the steering wheel when an autonomous driving mode or a stop mode in which the driver does not need to directly operate the steering wheel is selected as a driving mode of the autonomous vehicle.

[0006] For example, since the steering wheel protrudes toward the driver's seat and occupies a part of a space of the driver's seat, there is a problem in that the space utilization for providing a space for reading, viewing multimedia contents, sleeping, and the like for the driver deteriorates.

[0007] When the driver's seat is swiveled, the steering wheel causes interference, making it difficult to ensure a swivel trajectory of the driver's seat.

[0008] DE 10 2018 212 739 A1 describes a retractable steering system for a vehicle, comprising a steering tube connected to a steering wheel via a steering spindle, a steering column housing mounted on a crash pad, the steering tube being extendably inserted into the steering column housing, an electric motor mounted on an outer circumference of the steering column housing, a lead screw fixedly connected to an output shaft of the electric motor, a lead nut into which the lead screw is rotatably inserted, a retraction bracket fastened to the lead nut, a gear train mounted on the retraction bracket, the steering tube and the steering column housing and configured to form a movement path of the steering tube that is longer than a movement path of the lead nut and the retraction bracket.

[0009] DE 10 2016 125 839 A1 describes a method for controlling a retractable steering system with an electric motor, a steering tube and a steering column housing, into which the steering tube is extendably inserted and is movable with respect to the steering column housing by means of the electric motor according to each driving mode, which includes an autonomous driving mode and a manual driving mode, wherein, when a control device determines that a current driving mode of a vehicle is the autonomous driving mode, the electric motor is controlled by the control device electrically connected to the electric motor such that it rotates backwards in order to move and accommodate the steering tube in the steering column housing for a first predetermined time, and when the control device determines that the current driving mode is the manual driving mode, the electric motor is controlled by the control device such that it rotates forwards in order to move the steering tube,which is accommodated in the steering column housing, to extend into a predetermined first position for a first predetermined time so that a driver directly operates a steering wheel.

[0010] Another retractable steering system for a vehicle is known from DE 10 2019 114 991 A1.

[0011] The object of the invention is to provide a retractable steering system for a vehicle, which is configured to maximize the space utilization of a driver's seat by performing a retraction operation in which a steering wheel, a steering shaft, a cover, and the like are accommodated in the crash pad when an autonomous driving mode, a stop mode, or an entry / exit mode in which a driver does not need to directly operate the steering wheel is selected as a driving mode of an autonomous vehicle, and which is configured to ensure the comfort of use and the safety of a steering wheel by performing an extension operation in which the steering wheel, a steering shaft, a cover, and the like are spread out from an interior of a crash pad toward a driver's seat when a driving mode of an autonomous vehicle is changed to a manual driving mode in which a driver directly operates the steering wheel.an autonomous driving failure mode and an active safety mode to cope with a collision avoidance inability.

[0012] The object is achieved according to the invention by a retractable steering system according to the features of claim 1 and a method for controlling a retractable steering system according to the features of claim 14. Advantageous further developments are described in the subclaims.

[0013] The invention provides a retractable (e.g., collapsible) steering system for a vehicle, the retractable steering system comprising: a steering tube connected to a steering wheel via a steering spindle (or a steering shaft), a steering column housing mounted on (or in) a crash pad such that the steering tube is extendable (or extendable) inserted into the steering column housing, an electric motor mounted on an outer diameter portion of the steering column housing, a lead screw fixedly connected to an output shaft of the electric motor, a lead nut into which the lead screw is rotatably inserted, a retraction bracket (or a collapsing bracket) fixed to the lead nut, a gear train mounted on the retraction bracket, the steering tube and the steering column housing and configured to form a forward / backward movement path of the steering tube (orgenerated) that is longer than a forward / backward movement distance of the lead nut and the retraction holder, and a control device electrically connected to the electric motor and configured to control an operation of an electric motor control unit electrically connected to the electric motor and control an operation of the electric motor according to each travel mode.

[0014] According to various aspects of the invention, the retractable steering system may further comprise: telescopic covers (e.g., fairings or shrouds) connected to a rear surface of the steering wheel and a front end portion of the steering column housing to cover the steering shaft and the steering tube, wherein the telescopic covers are extended when the steering shaft and the steering tube move in a first direction, and the telescopic covers overlap each other when the steering shaft and the steering tube move in a second direction opposite to the first direction.

[0015] According to various aspects of the invention, the covers may include: a first cover attached to a steering wheel connector mounted on the rear surface of the steering wheel, a third cover attached to the front end portion of the steering column housing by means of a connecting bracket, and a second cover sized to be inserted into the third cover and sized to allow the first cover to be inserted into the second cover, so that the second cover is slidably connected to the first cover and the third cover.

[0016] According to the invention, the gear train comprises: a movable rack mounted on an outer surface of the steering tube, a fixed rack mounted on an inner surface of the steering column housing, and a rotatable gear rotatably and axially provided on the retraction bracket connected to the lead nut, wherein the rotatable gear is configured to mesh with both the movable rack and the fixed rack.

[0017] According to various exemplary embodiments of the invention, the forward / backward movement distance of the steering tube may be set to be equal to or greater than twice the forward / backward movement distance of the guide nut and the retraction bracket.

[0018] According to further various exemplary embodiments of the invention, the control device may comprise: an assisted and automated driving control unit (ADCU) configured to provide current driving mode information of an autonomous vehicle, an electric motor control unit (MCU) electrically connected to the electric motor and configured to provide a turn-on signal or a turn-off signal for the electric motor, an airbag control unit (ACU) configured to provide a vehicle collision avoidance impossibility signal, a steering control module (SCM) electrically connected to the ADCU, the MCU, and the ACU and configured to control a rotation direction of the electric motor and an electrical power supply to the electric motor based on the driving mode information, the turn-on signal, the turn-off signal, and the collision avoidance impossibility signal,and a driver actuation switch connected to the SCM and configured to provide an entry signal to the SCM.

[0019] According to another exemplary embodiment of the invention, when the SCM receives an autonomous driving mode as a current driving mode from the ADCU, the SCM may perform electric current control such that the electric motor rotates reversely to move and accommodate the steering shaft and the steering tube in the steering column housing for a first predetermined time.

[0020] According to another further exemplary embodiment of the invention, when the SCM receives the retract signal from the driver actuation switch, the SCM may determine that a current condition is a park stop condition, and the SCM may perform electrical current control such that the electric motor rotates reversely to move and accommodate the steering shaft and the steering tube in the steering column housing for the first predetermined time.

[0021] According to yet another exemplary embodiment of the invention, when the SCM receives the electric motor off signal from the MCU, the SCM may determine that a current condition is an entry / exit condition, and the SCM may perform electric current control such that the electric motor rotates reversely to move and accommodate the steering shaft and the steering tube in the steering column housing for the first predetermined time.

[0022] According to yet another further exemplary embodiment of the invention, when the SCM receives a manual drive mode as a current drive mode from the ADCU, the SCM may perform electric current control such that the electric motor rotates forward to extend the steering shaft and the steering tube accommodated in the steering column housing to a predetermined position for a first predetermined time so that a driver directly operates the steering wheel.

[0023] According to yet another exemplary embodiment of the invention, when the SCM receives the electric motor turn-on signal from the MCU, the SCM may determine that a current condition of the vehicle is a vehicle start condition, and the SCM may perform electric current control such that the electric motor rotates forward to extend the steering shaft and the steering tube accommodated in the steering column housing to a predetermined position for the first predetermined time so that a driver directly operates the steering wheel.

[0024] According to another exemplary embodiment of the invention, when the SCM receives an autonomous driving failure mode as a current driving mode from the ADCU, the SCM may perform electric current control such that the electric motor rotates forward to extend the steering shaft and the steering tube accommodated in the steering column housing to a predetermined position within a second predetermined time shorter than the first predetermined time, so that a driver directly operates the steering wheel.

[0025] According to yet another exemplary embodiment of the invention, when the SCM receives the collision avoidance impossibility signal from the ACU, the SCM may perform electric current control such that the electric motor rotates forward to extend the steering shaft and the steering tube accommodated in the steering column housing to a predetermined position within a third predetermined time shorter than the second predetermined time, so that a driver directly operates the steering wheel.

[0026] According to yet another exemplary embodiment of the invention, a receiving space in which the steering wheel is inserted and received may be formed in a front surface of the crash pad.

[0027] Various aspects of the invention provide the following effects through the above-mentioned solutions.

[0028] First, in the case of autonomous driving mode, stop mode, and entry / exit mode, in which the driver does not need to directly operate the steering wheel, the retraction process is performed in such a way that the steering wheel, steering shaft, covers, and the like are accommodated in the crash pad. As a result, it is possible to maximize the space utilization of the driver's seat by expanding its space.

[0029] Second, when the vehicle starts or when the vehicle is operating in manual drive mode, the extension operation is performed such that the steering wheel, steering shaft, covers, and the like are extended from the interior of the crash pad to the position where the driver can operate the steering wheel. As a result, it is possible to provide the driver with comfortable use of the steering wheel.

[0030] Third, in the case of the autonomous driving failure mode, the extension operation is performed such that the steering wheel, steering shaft, covers, and the like are quickly extended to the position where the driver can operate the steering wheel. As a result, it is possible to realize safe driving by allowing the driver to quickly steer (or control) the vehicle by operating the steering wheel.

[0031] Fourth, in the case of the active safety mode, to cope with the impossibility of avoiding a collision, the deployment process is performed in such a way that the steering wheel equipped with the airbag is more quickly extended to the position where the airbag is appropriately deployed toward the driver. As a result, it is possible to easily protect the driver by appropriately deploying the airbag.

[0032] It is understood that the term "vehicle" or "vehicular" or other similar term, as used herein, encompasses general motor vehicles, such as passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft, including a variety of boats and ships, aircraft, and the like, as well as hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from feedstocks other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more power sources, for example, both gasoline power and electric power.

[0033] The invention is explained in more detail with reference to the drawing. The drawing shows: Fig. 1 is a side view of a retractable steering system for a vehicle according to various exemplary embodiments of the invention; Fig. 2 and Fig. 3 are bottom views of a gear train of the retractable steering system for a vehicle according to various exemplary embodiments of the invention; Fig. 4 is a side view of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in a state in which covers are extended; Fig. 5 a section along the line AA in Fig. 4; Fig. 6 is a side view of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in a state where the covers overlap each other; Fig. 7 is a schematic plan view of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in a state in which a steering wheel is received in a crash pad; Fig. 8 is a view showing a configuration of a control device of the retractable steering system for a vehicle according to various exemplary embodiments of the invention; and Fig. 9 to 11 are flowcharts of examples of operation of the retractable steering system for a vehicle according to various exemplary embodiments of the invention.

[0034] It should be understood that the attached drawings are not necessarily to scale and represent a somewhat simplified representation of various features illustrating the basic principles of the invention. The specific design features of the present invention, including, for example, specific dimensions, orientations, positions, and shapes disclosed herein, will be determined in part by the particular intended application and usage environment.

[0035] In the figures, reference numerals refer to the same or equivalent parts of the present invention throughout the individual figures of the drawing.

[0036] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention has been described in connection with exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, variations, and other embodiments which may be included within the scope of the invention as defined by the appended claims.

[0037] An exemplary embodiment of the invention will now be described in detail with reference to the accompanying drawings.

[0038] Fig. 1 is a side view of a retractable steering system for a vehicle according to various exemplary embodiments of the invention, Fig. 2 is a view of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in an extended state in which a steering tube is moved by a gear train toward a driver's seat at a rear side, and Fig. 3 is a view of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in a retracted state in which the steering tube is moved by the gear train into a steering column housing at a front side.

[0039] As in the Fig. 1 and Fig. 2, the retractable steering system includes a steering spindle 12 connected to a steering wheel 10, a steering tube 14 in which the steering spindle 12 is inserted and secured, and a steering column housing 16 mounted in a crash pad such that the steering tube 14 is extendably inserted into the steering column housing 16.

[0040] An electric motor 20 is mounted at a predetermined position on an outer diameter portion of the steering column housing 16. A lead screw 22 is connected to an output shaft of the electric motor 20 so as to be rotatable in place, and the lead screw 22 is arranged parallel to a longitudinal direction of the steering column housing 16.

[0041] A lead nut 24 is fixed to the lead screw 22, and a retraction holder 30 is mounted on an inner end portion of the lead nut 24.

[0042] Therefore, when the lead screw 22 is rotated in place by operation of the electric motor 20, the lead nut 24 and the retraction holder 30 move linearly together in a forward / backward direction thereof.

[0043] A gear train 40 is mounted on the retraction bracket 30, the steering tube 14, and the steering column housing 16 and is configured to form a forward / backward movement path of the steering tube 14 that is longer than a forward / backward movement path of the guide nut 24 and the retraction bracket 30.

[0044] For this purpose, the gear train 40 may include a movable rack 42 mounted longitudinally on an outer surface of the steering tube 14, a fixed rack 44 mounted longitudinally on an inner surface of the steering column housing 16, and a rotatable gear 46 rotatably and axially provided on the retraction bracket 30 and configured to engage both the movable rack 42 and the fixed rack 44.

[0045] When the lead nut 24 and the retraction bracket 30 move linearly toward the driver's seat at the rear, since the lead screw 22 is rotated forward by forward rotation of the electric motor 20 in place, the rotatable gear 46 moves along the fixed rack 44 while rotating in one direction and simultaneously pushes the movable rack 42 toward the driver's seat at the rear.

[0046] Therefore, as in Fig. 2, an extension operation is performed such that the steering tube 14 and the steering shaft 12, on which the movable rack 42 is mounted, move straightly toward the driver's seat at the rear, and the steering wheel 10, which is fixed to the steering shaft 12, is placed in a position in which a driver can directly operate the steering wheel 10.

[0047] In contrast, when the lead nut 24 and the retraction holder 30 move forward in a straight line, since the lead screw 22 is rotated backward in place by a reverse rotation of the electric motor 20, the rotatable gear 46 moves along the fixed rack 44 while rotating in the other direction and at the same time pulls the movable rack 42 forward.

[0048] Therefore, as in Fig. 3, a retraction operation is carried out such that the steering tube 14, on which the movable rack 42 is mounted, is inserted and received in the steering column housing 16 at the front thereof.

[0049] Based on the operation of the gear train 40, the forward / backward moving distance of the steering tube 14 (about 150 mm) can be set to twice or more than the forward / backward moving distance of the guide nut 24 and the retraction holder 30 (about 75 mm).

[0050] Therefore, when the steering tube 14 is moved forward to the maximum and is inserted and received in the steering column housing 16 at the front, the steering shaft 12 is also moved forward to the maximum, and the steering wheel 10 connected to the steering shaft 12 is also inserted and received in a receiving space 102 formed in a front surface of a crash pad 100, as shown in Fig. 7 is shown.

[0051] A space of the driver's seat is expanded when the steering tube 14 is moved forward to the maximum and is inserted and accommodated in the steering column housing 16 at the front, and the steering wheel 10 is also moved forward and accommodated in the accommodation space 102 of the crash pad 100, as described above. As a result, it is possible to maximize the space utilization of the driver's seat by providing the driver with space for reading, viewing multimedia content, sleeping, and the like, and it is possible to easily ensure a pivoting trajectory of the driver's seat by preventing the steering wheel from interfering with the driver's seat when the driver's seat is pivoted.

[0052] Meanwhile, since the steering shaft 12 and the steering tube 14 are driving components, it is necessary to prevent contact of the steering shaft 12 and the steering tube 14 with the driver's body and to protect the steering shaft 12 and the steering tube 14 from external force and foreign matter.

[0053] For this purpose, the steering spindle 12 and the steering tube 14 are covered by covers arranged between the crash pad 100 and the steering wheel 10, so that the external appearances of the steering spindle 12 and the steering tube 14 are not visible.

[0054] However, since the covers may interfere with the forward movement of the steering tube 14 and the steering wheel 10, telescopic covers 50 are mounted between a rear surface of the steering wheel 10 and a front end portion of the steering column housing 16 to avoid the interference, as shown in Fig. 4 is shown.

[0055] The telescopic covers 50 are structured to cover the steering shaft 12 and the steering tube 14, and are configured to extend when the steering shaft 12 and the steering tube 14 move rearward and overlap each other when the steering shaft 12 and the steering tube 14 move forward therefrom.

[0056] More detailed information can be found in Fig. 4, the covers 50 include a first cover 51 fixed to a caster connector 11 mounted on a rear surface of the steering wheel 10, a third cover 53 fixed to the front end portion of the steering column housing 16, and a second cover 52 sized to be inserted into the third cover 53 and allowing the first cover 51 to be inserted into the second cover 52, and the second cover 52 is slidably connected to the first cover 51 and the third cover 53.

[0057] In the present case, as in Fig. 5, the first cover 51 is attached and fixed to a front end portion of the caster connector 11 by means of screws 55. As shown in Fig. 4, the third cover 53 may be attached and fixed to the front end portion of the steering column housing 16 by means of a separate connecting bracket 54.

[0058] For reference, the steering wheel connector 11 is a component configured to transmit an electrical signal to components such as an airbag and a remote control device provided on the steering wheel 10.

[0059] Therefore, as in Fig. 6, when the steering wheel 10 and the steering tube 14 move forward, the first cover 51 is inserted into the second cover 52 and overlaps the second cover 52, and continuously, the second cover 52 is inserted into the third cover 53 and overlaps the third cover 53, so that the steering wheel 10 and the steering tube 14 can be easily inserted and received in the steering column housing 16 at the front.

[0060] In contrast, when the steering wheel 10 and the steering tube 14 move toward the driver's seat at the rear, the second cover 52 is extended from the third cover 53, and continuously, the first cover 51 is extended from the second cover 52, so that the first, second and third covers 51, 52 and 53 are extended when the steering wheel 10 and the steering tube 14 move completely toward the driver's seat at the rear, as shown in Fig. 4 is shown.

[0061] Meanwhile, an operation of controlling the entire retractable steering system according to various exemplary embodiments of the invention may be performed by a single integrated control device configured to control the operation of the electric motor 20 for each traveling mode, or by a control device formed by combining a plurality of control devices.

[0062] For this purpose, as in Fig. 8, the controller 60 includes an assisted and automated driving control unit (ADCU) 61 configured to provide current drive mode information of an autonomous vehicle to a steering control module (SCM) 64, an electric motor control unit (MCU) 62 configured to provide the SCM 64 with an on / off signal for the electric motor, an airbag control unit (ACU) 63 configured to provide the SCM 64 with a vehicle collision avoidance impossibility signal, the SCM 64 configured to control a rotation direction of the electric motor and an electric power supply to the electric motor based on the drive mode information, the on / off signal, and the collision avoidance impossibility signal, and a driver operation switch 65 configured to provide the SCM 64 with an entry signal.

[0063] In the present case, an operation sequence and a control operation of the retractable steering system according to various exemplary embodiments of the invention will be described below.

[0064] Fig. 9 is a flowchart illustrating an operation sequence of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in an autonomous driving mode and a manual driving mode.

[0065] To Fig. 9, when the SCM 64 receives the manual drive mode as the current drive mode from the ADCU 61, the SCM 64 performs pulse width modulation (PWM) electric power supply control to rotate the electric motor 20 forward so that the steering shaft 12 and the steering tube 14 accommodated in the steering column housing 16 extend to a position in which the driver directly operates the steering wheel 10 for a first predetermined time (about 7 seconds).

[0066] Alternatively, when the SCM 64 receives the autonomous driving mode as a current driving mode from the ADCU 61, the SCM 64 performs the PWM electric power supply control to rotate the electric motor 20 reversely so that the steering shaft 12 and the steering tube 14 are moved and accommodated in the steering column housing 16 for the first predetermined time (about 7 seconds).

[0067] For this purpose, the SCM 64 first determines which of the driving modes is the current driving mode (S101).

[0068] If the determination result indicates that the current driving mode is the manual driving mode, the SCM 64 determines whether the current state is the retraction state (S102).

[0069] That is, the SCM 64 determines whether the current state is the retracted state or the extended state, wherein the retracted state represents a state in which the steering tube 14 is inserted and accommodated in the steering column housing 16 and the steering wheel 10 is also accommodated in the accommodation space 102 formed in the front surface of the crash pad 100, as shown in Fig. 7, and the extended state represents a state in which the steering tube 14 is moved straightly toward the driver's seat at the rear and the steering wheel 10 is placed in the position in which the driver can directly operate the steering wheel 10.

[0070] When the determination result indicates that the current state is the retraction state, the SCM 64 performs the electric power supply control to rotate the electric motor 20 forward so that the extension operation is performed within the first predetermined time (about 7 seconds) (S104).

[0071] More detailed information is available with reference to Fig. 2 described above, the extension operation is performed within the first predetermined time (about 7 seconds), so that since the lead screw 22 is rotated forward by the forward rotation of the electric motor 20 in place, the lead nut 24 and the retraction holder 30 are moved linearly toward the driver's seat at the rear, and the rotatable gear 46 moves along the fixed rack 44 while rotating in one direction and at the same time pushes the movable rack 42 toward the driver's seat at the rear, so that the steering tube 14 and the steering shaft 12, to which the movable rack 42 is mounted, move linearly toward the driver's seat at the rear, and the steering wheel 10 is placed in the position where the driver can directly operate the steering wheel 10.

[0072] In this case, if the determination result in step S102 indicates that the current state is the extension state, the SCM 64 maintains the current state as it is (S103).

[0073] Therefore, in the manual driving mode, manual driving can be performed in which the driver directly operates the steering wheel 10.

[0074] When the SCM 64 receives a motor turn-on signal from the MCU 62, the SCM 64 determines that the current condition is a vehicle start condition, and the SCM 64 performs electric power supply control to rotate the electric motor 20 forward so that the steering shaft 14 housed in the steering column housing 16 extends to the position where the driver directly operates the steering wheel 10 within the first predetermined time, thus enabling the extension operation. As a result, manual driving, in which the driver directly operates the steering wheel 10, can be performed when the vehicle starts.

[0075] In contrast, when the determination result in step S101 indicates that the current driving mode is the autonomous driving mode, the SCM 64 determines whether the current state is the retraction state (S105).

[0076] When the determination result indicates that the current state is the extension state, the SCM 64 performs the electric power supply control to rotate the electric motor 20 reversely so that the retraction operation is performed within the first predetermined time (about 7 seconds) (S107).

[0077] More detailed information is available with reference to Fig. 2 described above, the retraction operation is performed within the first predetermined time (about 7 seconds), so that since the lead screw 22 is rotated reversely by the reverse rotation of the electric motor 20 in place, the lead nut 24 and the retraction holder 30 are moved forward linearly, and the rotatable gear 46 moves along the fixed rack 44 while rotating in the other direction and simultaneously pulls the movable rack 42 forward, so that the steering tube 14 with the movable rack 42 mounted thereon is inserted and received in the steering column housing 16 at the front, and at the same time, the steering wheel 10 is inserted and received in the receiving space 102 formed in the front surface of the crash pad 100.

[0078] Therefore, the space of the driver's seat is expanded in the autonomous driving mode, and as a result, it is possible to maximize the space utilization of the driver's seat by providing the space for reading, viewing multimedia contents, sleeping, and the like for the driver, and it is possible to easily ensure the pivoting trajectory of the driver's seat by preventing the steering wheel from interfering with the driver's seat when the driver's seat is pivoted.

[0079] For reference, the SCM 64 may determine the retracted state and the extended state based on the amount of forward or reverse rotation of the electric motor 20 or using a signal from a position sensor configured to detect a position of the steering tube 14.

[0080] When the SCM 64 receives the retraction signal from the separate driver operation switch 65, the SCM 64 determines that the current condition is a parking stop condition, and the SCM 64 performs the electric power supply control to reversely rotate the electric motor 20 so that the steering shaft 12 and the steering tube 14 can be moved and accommodated in the steering column housing 16 for the predetermined time, thus performing the retraction operation. As a result, the wide space of the driver's seat can be utilized even in the parking stop state of the vehicle.

[0081] Alternatively, when the SCM 64 receives a motor-off signal from the MCU 62, the SCM 64 determines that the current condition is a getting-in / out condition, and the SCM 64 performs electric power supply control to reversely rotate the electric motor 20 so that the steering shaft 12 and the steering tube 14 are moved and accommodated in the steering column housing 16 for the first predetermined time, allowing the retraction operation to be performed. As a result, it is possible to improve the getting-in / out comfort by ensuring a wide passageway for the driver to get in and out of the vehicle.

[0082] Fig. 10 is a flowchart illustrating an operation of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in an autonomous driving failure mode.

[0083] To Fig. 10, when the SCM 64 receives the autonomous driving failure mode as a current driving mode from the ADCU 61, the SCM 64 performs the PWM electric power supply control to rotate the electric motor 20 forward so that the steering shaft 12 and the steering tube 14 accommodated in the steering column housing 16 extend to the position in which the driver directly operates the steering wheel 10 within a second predetermined time (about 4 seconds) shorter than the first predetermined time.

[0084] For this purpose, the SCM 64 first determines whether the autonomous driving mode is operating normally (S201).

[0085] For example, when the SCM 64 receives the autonomous driving failure mode as a current driving mode from the ADCU 61, the SCM 64 determines that the autonomous driving mode is not operating normally.

[0086] If the determination result indicates that the autonomous driving mode is not operating normally, the SCM 64 determines whether the current state is the retraction state (S202).

[0087] That is, the SCM 64 determines whether the current state is the retracted state or the extended state, wherein the retracted state represents a state in which the steering tube 14 is inserted and accommodated in the steering column housing 16 and the steering wheel 10 is also accommodated in the accommodation space 102 formed in the front surface of the crash pad 100, as shown in Fig. 7, and the extended state represents a state in which the steering tube 14 is moved straightly toward the driver's seat at the rear and the steering wheel 10 is placed in the position in which the driver can directly operate the steering wheel 10.

[0088] When the determination result indicates that the current state is the retraction state, the SCM 64 performs the electric power supply control to rotate the electric motor 20 forward so that the extension operation is performed within the second predetermined time (about 4 seconds) (S204).

[0089] In the present case, the extending operation can be performed within the second predetermined time (about 4 seconds) by increasing the electric current to be supplied during the PWM electric power supply control for rotating the electric motor 20 forward thereof.

[0090] More detailed information is available with reference to Fig. 2 described above, the extension operation is performed within the second predetermined time (about 4 seconds), so that since the lead screw 22 is rotated forward by the forward rotation of the electric motor 20 in place, the lead nut 24 and the retraction holder 30 are moved linearly toward the driver's seat at the rear, and the rotatable gear 46 moves along the fixed rack 44 while rotating in one direction and at the same time pushes the movable rack 42 toward the driver's seat at the rear, so that the steering tube 14 and the steering shaft 12, to which the movable rack 42 is mounted, move linearly toward the driver's seat at the rear, and the steering wheel 10 is placed in the position where the driver can directly operate the steering wheel 10.

[0091] In this case, if the determination result in step S202 indicates that the current state is the extension state, the SCM 64 maintains the current state as it is (S203).

[0092] Therefore, in the autonomous driving failure mode, manual driving can be performed in which the driver directly operates the steering wheel 10.

[0093] Fig. 11 is a flowchart illustrating an operation of the retractable steering system for a vehicle according to various exemplary embodiments of the invention in an active safety mode for coping with a collision avoidance impossibility.

[0094] To Fig. 11, when the SCM 64 receives a collision avoidance impossibility signal (e.g., a collision signal for deploying an airbag) from the ACU 63, the SCM 64 performs the PWM electric power supply control to rotate the electric motor 20 forward so that the steering shaft 12 and the steering tube 14 accommodated in the steering column housing 16 extend to the position in which the driver directly operates the steering wheel 10 within a third predetermined time (about 2 seconds) shorter than the second predetermined time.

[0095] For this purpose, the ACU 63 first detects whether the frontal collision may occur according to a signal from a collision detection sensor (S301).

[0096] Next, the SCM 64 determines whether collision avoidance is possible (S302).

[0097] For example, when the SCM 64 receives the collision avoidance impossible signal (e.g., the collision signal for deploying the airbag) from the ACU 63, the SCM 64 determines that collision avoidance is impossible.

[0098] If the determination result indicates that collision avoidance is impossible, the SCM 64 determines whether the current state is the entry state (S303).

[0099] That is, the SCM 64 determines whether the current state is the retracted state or the extended state, wherein the retracted state represents a state in which the steering tube 14 is inserted and accommodated in the steering column housing 16 and the steering wheel 10 is also accommodated in the accommodation space 102 formed in the front surface of the crash pad 100, as shown in Fig. 7, and the extended state represents a state in which the steering tube 14 is moved straightly toward the driver's seat at the rear and the steering wheel 10 is placed in the position in which the driver can directly operate the steering wheel 10.

[0100] When the determination result indicates that the current state is the retraction state, the SCM 64 performs the electric power supply control to rotate the electric motor 20 forward so that the extension operation is performed within the third predetermined time (about 2 seconds) (S305).

[0101] In the present case, the extending operation can be performed within the third predetermined time (about 2 seconds) by further increasing the electric current to be supplied during the PWM electric power supply control for rotating the electric motor 20 forward thereof.

[0102] More detailed information is available with reference to Fig.2 described above, the extension operation is performed within the third predetermined time (about 2 seconds), so that since the lead screw 22 is rotated forward by the forward rotation of the electric motor 20 in place, the lead nut 24 and the retraction holder 30 are moved linearly toward the rear driver's seat, and the rotatable gear 46 moves along the fixed rack 44 while rotating in one direction and simultaneously pushes the movable rack 42 toward the rear driver's seat, so that the steering tube 14 and the steering shaft 12, to which the movable rack 42 is mounted, move linearly toward the rear driver's seat, and the steering wheel 10 is placed in the position where the driver can directly operate the steering wheel 10.

[0103] In this case, if the determination result in step S301 indicates that the current state is the extension state, the SCM 64 maintains the current state as it is (S304).

[0104] Therefore, when the vehicle collision avoidance is impossible, the steering wheel 10 can be quickly moved to the position where the driver directly operates the steering wheel 10 within the third predetermined time, and the airbag mounted in the steering wheel 10 can be easily deployed toward the driver, so that injury to the driver caused by the deployment of the airbag is easily prevented.

[0105] Furthermore, the term "controller," "control unit," "control device," or "control module" refers to a hardware device comprising a memory and a processor configured to execute one or more steps interpreted as an algorithm structure. The memory stores algorithm steps, and the processor executes the algorithm steps to perform one or more processes of a method according to various exemplary embodiments of the invention.The control device according to exemplary embodiments of the invention may be implemented by a non-volatile memory configured to store algorithms for controlling the operation of various components of a vehicle or data via software instructions for executing the algorithms, and a processor configured to perform an operation described above using the data stored in the memory. The memory and the processor may be individual chips. Alternatively, the memory and the processor may be integrated into a single chip. The processor may be implemented as one or more processors. The processor may include various logic circuits and operation circuits, may process data according to a program provided by the memory, and may generate a control signal according to the processing result.

[0106] The control device may be at least one microprocessor operated by a predetermined program which may comprise a series of instructions for carrying out the method involved in the aforementioned various exemplary embodiments of the invention.

[0107] The invention described above can also be implemented as computer-readable codes in a computer-readable recording medium. The computer-readable recording medium is any data storage device capable of storing data that can subsequently be read by a computer system. Examples of the computer-readable recording medium include a hard disk drive (HDD), a solid-state disk (SSD), a silicon disk drive (SDD), a read-only memory (ROM), a random access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, etc., and implementation as carrier waves (e.g., transmission over the Internet).

[0108] In various exemplary embodiments of the invention, each operation described above may be performed by a control device, and the control device may be configured by a plurality of control devices or an integrated single control device.

[0109] In various exemplary embodiments of the invention, the control device may be implemented in a form of hardware or software, or may be implemented in a combination of hardware and software.

[0110] For ease of explanation and precise definition in the appended claims, the terms "top," "bottom," "inside," "outside," "front," and "rear" are used to describe features of the exemplary embodiments with reference to the positions of these features as shown in the figures. It is further understood that the term "connect" or variations thereof refer to both direct and indirect connection.

Claims

[1] Retractable steering system for a vehicle, the retractable steering system comprising: a steering tube (14) connected to a steering wheel (10) via a steering spindle (12), a steering column housing (16) mounted on a crash pad (100), wherein the steering tube (14) is extendably inserted into the steering column housing (16), an electric motor (20) mounted on an outer circumference of the steering column housing (16), a lead screw (22) which is fixedly connected to an output shaft of the electric motor (20), a lead nut (24) into which the lead screw (22) is rotatably inserted, a retraction holder (30) which is attached to the guide nut (24), a gear train (40) mounted on the retraction bracket (30), the steering tube (14) and the steering column housing (16) and configured to form a travel path of the steering tube (14) that is longer than a travel path of the guide nut (24) and the retraction bracket (30), and a control device (60) electrically connected to the electric motor (20) and configured to control an operation of an electric motor control unit (62) electrically connected to the electric motor (20) and to control an operation of the electric motor (20) according to each driving mode, wherein the gear train (40) comprises: a movable rack (42) mounted on an outer surface of the steering tube (14), a stationary rack (44) mounted on an inner surface of the steering column housing (16), and a rotatable gear (46) rotatably provided on the retraction holder (30) connected to the guide nut (24) and meshing with the movable rack (42) and the fixed rack (44). [2] A retractable steering system according to claim 1, further comprising: telescopic covers (50) connected to a rear surface of the steering wheel (10) and a front end portion of the steering column housing (16) to cover the steering spindle (12) and the steering tube (14), wherein the telescopic covers (50) are extended when the steering spindle (12) and the steering tube (14) move in a first direction, and the telescopic covers (50) overlap each other when the steering spindle (12) and the steering tube (14) move in a second direction opposite to the first direction. [3] A retractable steering system according to claim 2, wherein the covers (50) comprise: a first cover (51) attached to a caster connector (11) mounted on the rear surface of the steering wheel (10), a third cover (53) which is fixed to the front end portion of the steering column housing (16) by means of a connecting bracket (54), and a second cover (52) dimensioned to be insertable into the third cover (53) and allowing the first cover (51) to be inserted into the second cover (52) such that the second cover (52) is slidably connected to the first cover (51) and the third cover (53). [4] A retractable steering system according to any one of claims 1 to 3, wherein the moving distance of the steering tube (14) is set to be equal to or greater than twice the moving distance of the guide nut (24) and the retractable holder (30). [5] Retractable steering system according to one of claims 1 to 4, wherein the control device (60) comprises: an assisted and automated driving control unit (ADCU) (61) configured to provide current driving mode information of an autonomous vehicle, the electric motor control unit (MCU) (62) which is electrically connected to the electric motor (20) and is configured to provide a switch-on signal or a switch-off signal for the electric motor (20), an airbag control unit (ACU) (63) configured to provide a vehicle collision avoidance impossibility signal, a steering control module (SCM) (64) electrically connected to the ADCU (61), the MCU (62) and the ACU (63) and configured to control a rotation direction of the electric motor (20) and an electric power supply to the electric motor (20) according to the current driving mode information, the switch-on signal, the switch-off signal and the collision avoidance impossibility signal, and a driver actuation switch (65) connected to the SCM (64) and configured to provide an entry signal to the SCM (64). [6] Retractable steering system according to claim 5, each driving mode has an autonomous driving mode, and wherein, when the SCM (64) receives the autonomous driving mode as a current driving mode from the ADCU (61), the SCM (64) is configured to control the electric motor (20) to rotate reversely to move and accommodate the steering shaft (12) and the steering tube (14) in the steering column housing (16) for a first predetermined time. [7] A retractable steering system according to claim 5 or 6, wherein when the SCM (64) receives the retract signal from the driver actuation switch (65), the SCM (64) is configured to determine that a current condition of the vehicle is a park stop condition, and the SCM (64) is configured to control the electric motor (20) to rotate reversely to move and accommodate the steering shaft (12) and the steering tube (14) within the steering column housing (16) for a first predetermined time. [8] A retractable steering system according to any one of claims 5 to 7, wherein when the SCM (64) receives the disable signal from the MCU (62), the SCM (64) is configured to determine that a current condition of the vehicle is an ingress / egress condition, and the SCM (64) is configured to control the electric motor (20) to rotate reversely to move and accommodate the steering shaft (12) and the steering tube (14) within the steering column housing (16) for a first predetermined time. [9] Retractable steering system according to one of claims 5 to 8, each driving mode having a manual driving mode, and wherein, when the SCM (64) receives the manual drive mode as a current drive mode from the ADCU (61), the SCM (64) is configured to control the electric motor (20) to rotate forward to extend the steering shaft (12) and the steering tube (14), which are housed in the steering column housing (16), to a predetermined position for a first predetermined time so that a driver directly operates the steering wheel (10). [10] A retractable steering system according to any one of claims 5 to 9, wherein, when the SCM (64) receives the power-on signal from the MCU (62), the SCM (64) is configured to determine that a current condition of the vehicle is a vehicle start condition, and the SCM (64) is configured to control the electric motor (20) to rotate forward to extend the steering shaft (12) and the steering tube (14) housed in the steering column housing (16) to a predetermined position for a first predetermined time so that a driver directly operates the steering wheel (10). [11] Retractable steering system according to one of claims 5 to 9, wherein each driving mode has an autonomous driving failure mode, and wherein, when the SCM (64) receives the autonomous driving failure mode as a current driving mode from the ADCU (61), the SCM (64) is configured to control the electric motor (20) to rotate forward to extend the steering shaft (12) and the steering tube (14), which are accommodated in the steering column housing (16), to a predetermined position within a second predetermined time that is shorter than a first predetermined time, so that a driver directly operates the steering wheel (10). [12] A retractable steering system according to any one of claims 5 to 11, wherein, when the SCM (64) receives a collision avoidance impossibility signal from the ACU (63), the SCM (64) is configured to control the electric motor (20) to rotate forward to extend the steering shaft (12) and the steering tube (14) housed in the steering column housing (16) to a predetermined position within a third predetermined time shorter than a second predetermined time so that a driver directly operates the steering wheel (10). [13] A retractable steering system according to any one of claims 1 to 12, wherein a receiving space (102) in which the steering wheel (10) is inserted and received is formed in a front surface of the crash pad (100). [14] A method for controlling a retractable steering system having an electric motor (20), a steering tube (14) and a steering column housing (16), into which the steering tube (14) is extendably inserted and is movable with respect to the steering column housing (16) by means of the electric motor (20) according to each driving mode, which includes an autonomous driving mode, a manual driving mode and an autonomous driving error mode, the method comprising: when a control device (60) determines that a current driving mode of a vehicle is the autonomous driving mode, controlling the electric motor (20) by the control device (60) electrically connected to the electric motor (20) such that it rotates backward to move and accommodate the steering tube (14) in the steering column housing (16) for a first predetermined time, when the control device (60) determines that the current driving mode is the manual driving mode, controlling the electric motor (20) by the control device (60) such that it rotates forward to extend the steering tube (14), which is accommodated in the steering column housing (16), into a predetermined first position for a first predetermined time so that a driver directly operates a steering wheel (10), and when the control device (60) determines that the current driving mode is the autonomous driving failure mode in which the autonomous driving mode does not operate normally, controlling the electric motor (20) by the control device (60) such that it rotates forward to extend the steering tube (14) accommodated in the steering column housing (16) to a predetermined second position within a second predetermined time which is shorter than the first predetermined time, so that the driver directly operates the steering wheel (10). [15] The method of claim 14, further comprising: when the control device (60) receives a retraction signal, controlling the electric motor (20) by the control device (60) such that it rotates backward to move and accommodate the steering tube (14) in the steering column housing (16) for the first predetermined time. [16] The method of claim 14 or 15, further comprising: when the control device (60) receives a switch-off signal for the electric motor (20), controlling the electric motor (20) by the control device (60) such that it rotates backward to move and accommodate the steering tube (14) in the steering column housing (16) for the first predetermined time. [17] A method according to any one of claims 14 to 16, wherein, when the control device (60) determines that a current condition of a vehicle is a vehicle start condition, controlling the electric motor (20) by the control device (60) to rotate forward to extend the steering tube (14) received in the steering column housing (16) to a predetermined position for the first predetermined time so that a driver directly operates the steering wheel (10). [18] Method according to one of claims 14 to 17, further comprising: when the control device (60) receives a collision avoidance impossibility signal, controlling the electric motor (20) by the control device (60) such that it rotates forward to extend the steering tube (14) accommodated in the steering column housing (16) to a predetermined position within a third predetermined time which is shorter than the second predetermined time, so that a driver directly operates the steering wheel (10).

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