STEER-BY-WIRE SYSTEM WITH GEARS FOR RACK POSITION DETECTION

Abstract

A steer-by-wire system comprises: a first drive unit, comprising a first motor with a first motor shaft and a first gear configured to be rotated by a rotation of the first motor shaft; a second drive unit, comprising a second motor with a second motor shaft and a second gear configured to be rotated by a rotation of the second motor shaft; and a rack operationally coupled to the first motor of the first drive unit and the second motor of the second drive unit, the rack being configured to be linearly movable in response to a rotation of at least one of the first motor and the second motor.A processor is configured to identify a linear position of the rack based on a position of the first gear of the first drive unit and a position of the second gear of the second drive unit using a Vernier algorithm.

Description

[0001] This application claims the benefits of US patent application number 63 / 726,248, filed on November 28, 2024, entitled “ABSOLUTE RACK POSITION SENSING THROUGH MOTOR SHAFT - DRIVEN POSITION SENSORS AND A VERNIER ALGORITHM”, and US patent application number 19 / 399,631, filed on November 25, 2025, entitled “STEER-BY-WIRE-SYSTEM HAVING GEARS FOR RACK POSITION DETECTION”. BACKGROUND

[0002] Various embodiments of the present disclosure generally relate to a steering system for a vehicle and in particular to a steer-by-wire system.

[0003] Vehicles require a steering system to control their direction of travel. Until now, mechanical steering systems have been used. These systems typically involve a mechanical linkage or connection between a steering wheel and the vehicle's wheels. For example, in a conventional steering system consisting of a steering wheel, steering column, power-assisted rack and pinion system, the driver turns the steering wheel, which, through the various mechanical components, causes the vehicle's wheels to turn. Thus, the movement of the steering wheel results in a corresponding movement of the wheels. The movement of such mechanical systems is often power-assisted through the use of hydraulic assists or electric motors.

[0004] It is expected that mechanical steering systems will be replaced or supplemented by electrically driven steering systems, commonly known as "steer-by-wire" systems. Such steer-by-wire systems replace, to varying degrees, the mechanical linkage between the steering wheel and the vehicle's wheels with one or more sensors, actuators, and electronics. The steer-by-wire system aims to eliminate the physical or mechanical connection between the steering wheel and the vehicle's wheels, using electrically controlled motors to change the direction of the vehicle's wheels and provide feedback to the driver.Although the mechanical linkage between the steering wheel and the road wheels has been eliminated, the steer-by-wire system is expected not only to produce the same functions and steering feel as a conventional mechanically coupled steering system, but also to implement advanced steering system features. Requirements for conventional steering functions and advanced steering features, such as adjustable steering feel, can be implemented through an advanced steering system design.

[0005] With regard to these and other general considerations, the following embodiments have been described. Although relatively specific problems have been discussed, it is understood that the embodiments should not be limited to solving the specific problems identified in the background. SUMMARY

[0006] The features and advantages of the present disclosure will be more easily understood and become apparent from the following detailed description, which should be read in conjunction with the accompanying drawings, and from the claims appended at the end of the detailed description.

[0007] According to some embodiments of the present disclosure, a steer-by-wire system may comprise: a first drive unit comprising a first motor with a first motor shaft and a first gear configured to be rotated by a rotation of the first motor shaft; a second drive unit comprising a second motor with a second motor shaft and a second gear configured to be rotated by a rotation of the second motor shaft; and a rack operationally coupled to the first motor of the first drive unit and the second motor of the second drive unit, the rack being configured to be linearly movable in response to a rotation of at least one of the first motor and the second motor.

[0008] The steer-by-wire system may further include a processor configured to identify a linear position of the rack based on the position of the first gear of the first drive unit and the position of the second gear of the second drive unit.

[0009] A Vernier algorithm can be used to identify the linear position of the rack based on the position of the first gear of the first drive unit and the position of the second gear of the second drive unit.

[0010] The first motor shaft can include a first shaft gear that is rotatably engaged with the first gear of the first drive unit, and the second motor shaft can include a second shaft gear that is rotatably engaged with the second gear of the second drive unit.

[0011] The transmission ratio between the first shaft gear and the first gear, which are rotatably engaged with each other, and the transmission ratio between the second shaft gear and the second gear, which are rotatably engaged with each other, can be different from each other.

[0012] The diameter or number of teeth of the first gear of the first drive assembly may be larger than the diameter or number of teeth of the first shaft gear, and the diameter or number of teeth of the second gear of the second drive assembly may be larger than the diameter or number of teeth of the second shaft gear.

[0013] The first drive unit can include a first gear position sensor configured to detect the position of the first gear of the first drive unit, and the second drive unit can include a second gear position sensor configured to detect the position of the second gear of the second drive unit.

[0014] The first gear of the first drive unit and / or the second gear of the second drive unit may contain magnetic material, and the first gear position sensor and / or the second gear position sensor may be configured to detect a magnetic field to identify the position of the first gear of the first drive unit and / or the position of the second gear of the second drive unit, respectively.

[0015] The first gear of the first drive unit and / or the second gear of the second drive unit may contain metallic material, and the first gear position sensor and / or the second gear position sensor may be inductive sensors configured to identify the position of the first gear of the first drive unit and / or the position of the second gear of the second drive unit using electromagnetic induction associated with the metallic material of the first gear and / or the second gear, respectively.

[0016] The first gear can be rotatably mounted on an inner surface of a first drive unit housing, and the second gear can be rotatably mounted on an inner surface of a first drive unit housing.

[0017] The first drive unit can include a first circuit board on which a first gear position sensor is mounted, configured to detect a position of the first gear of the first drive unit, and the second drive unit can include a second circuit board on which a second gear position sensor is mounted, configured to detect a position of the second gear of the second drive unit.

[0018] The first gear of the first drive assembly, configured to be rotated by a rotation of the first motor shaft, may have a first groove in which a first magnet is fitted, and the second gear of the second drive assembly, configured to be rotated by a rotation of the second motor shaft, may have a second groove in which a second magnet is fitted.

[0019] At least one of the first motor shafts or the second motor shaft can have a shaft cover that covers a section of the first motor shaft or the second motor shaft, with the first shaft gear or the second shaft gear being provided on an outer surface of the shaft cover.

[0020] At least one of the first motor shafts or the second motor shaft can have a shaft cover that covers a section of the first motor shaft or the second motor shaft, with a magnet attached to the shaft cover.

[0021] The magnet can be located inside the shaft cover.

[0022] The steer-by-wire system may further include a rotary-to-linear conversion mechanism which is operationally coupled to the first motor of the first drive unit and the second motor of the second drive unit and is configured to convert a rotary motion generated by at least one of the first motor of the first drive unit and the second motor of the second drive unit into a linear motion for linear movement of the rack.

[0023] The rotary-to-linear conversion mechanism may include a rotatable part that surrounds at least part of the rack to be rotatably coupled to the rack, and the rack may be configured to be linearly movable in response to a rotation of the rotatable part of the rotary-to-linear conversion mechanism.

[0024] The steer-by-wire system may further comprise: a first belt that operationally connects the first motor of the first drive unit to the rotating part of the rotary-to-linear conversion mechanism; and a second belt that operationally connects the second motor of the second drive unit to the rotating part of the rotary-to-linear conversion mechanism, the first belt being coupled to one section of the rotating part of the rotary-to-linear conversion mechanism and the second belt being coupled to another section of the rotating part of the rotary-to-linear conversion mechanism.

[0025] The first motor shaft of the first drive unit and the second motor shaft of the second drive unit can be arranged so that they are coaxial to each other.

[0026] The steer-by-wire system may further include one or more bearings that support the rotatable part of the rotary-to-linear conversion mechanism, which surrounds at least part of the rack.

[0027] This summary is provided to introduce, in a simplified form, a selection of concepts that are described in detail below. This summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various embodiments according to the present disclosure are described with reference to the drawings: Fig. Figure 1 is a schematic view that schematically illustrates a steering device according to an embodiment of the present disclosure; Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. Figure 7 are partial views illustrating a steering device according to embodiments of the present disclosure; Fig. Figure 8 is a schematic view that schematically illustrates a steering device according to an embodiment of the present disclosure; Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17 to Fig. Figure 18 are partial views illustrating a steering device according to one embodiment of the present disclosure; Fig. Figure 19 is a diagram illustrating a method for estimating a rack position according to a difference between first rotation information of a first motor and second rotation information of a second motor according to an embodiment of the present disclosure; Fig. Figure 20 is a schematic view of a vehicle incorporating a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. Figure 21 is a perspective view showing a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. Figure 22 is a cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. Figure 23 is a partial cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. 24- Fig. Figure 25 is a perspective partial view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. 26- Fig. Figure 27 shows partial cross-sectional views to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure; Fig. Figure 28 is a partial top view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure; and Fig. Figure 29 is a perspective partial view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF EXECUTION FORMS

[0029] The following detailed description refers to the accompanying drawings, which form part of the present disclosure and illustrate specific embodiments in which the invention can be carried out. These embodiments are described in sufficient detail to enable a person skilled in the art to carry out the invention. It is understood that other embodiments may be used and that structural, logical, and electrical modifications may be made without departing from the basic concept and scope of the invention. The following detailed description is therefore not to be understood in a limiting sense, and the scope of the invention is defined only by the attached claims and equivalents thereof. Identical numbers in the figures refer to identical components, which should be obvious from the context of use.

[0030] A steering device according to one embodiment of the present disclosure comprises a ball nut 141, a first nut pulley 143a, a second nut pulley 143b, a first motor pulley 142a, a second motor pulley 142b, and an electronic control unit 110. The ball nut 141 can be rotatably coupled to a rack 130 by means of balls 144 and can be configured to displace the rack 130 in an axial direction by rotating the ball nut 141. The first nut pulley 143a can be provided on an outer circumferential surface of the ball nut 141, and the second nut pulley 143b can be provided on an outer circumferential surface of the first ball nut 141. The first motor pulley 142a can be coupled to a first motor 145 (e.g.,The first motor pulley 142b can be attached to a shaft of the first motor 145 or be formed directly on a rotatable part of the first motor 145 and connected to a first nut pulley 143a by a first belt 149a. The second motor pulley 142b can be coupled to a second motor 147 (e.g., attached to a shaft of the second motor 147) or formed directly on a rotatable part of the second motor 147 and connected to the second nut pulley 143b by a second belt 149a. The electronic control unit 110 can include one or more controllers or processors and can be configured to control the first and second motors 145 and 147. For example, the electronic control unit 110 outputs one or more control signals to the first motor 145 and the second motor 147 in response to one or more electrical signals.

[0031] With reference to Fig. 1 In a steering device according to the present disclosure, an angle sensor 105 and a torque sensor 107 can be coupled to a side of a steering shaft 103 which is connected to a steering wheel 101 or arranged around the steering shaft 103.

[0032] In an autonomous driving mode, in which an autonomous driving system drives the vehicle, or in a driver assistance mode, in which a driver assistance system, such as an Advanced Driver Assistance System (ADAS), assists a driver in operating the vehicle, the electronic control unit 110 controls a steering shaft motor 120, the first motor 145 and the second motor 147 by transmitting one or more control signals to the steering shaft motor 120, the first motor 145 and the second motor 147 in response to electrical signals transmitted by various sensors that are installed in or on or associated with a vehicle.

[0033] In a driver driving mode, the electronic control unit 110 controls the steering shaft motor 120, the first motor 145 and the second motor 147 by outputting one or more control signals to the steering shaft motor 120, the first motor 145 and the second motor 147 in response to electrical signals transmitted by the angle sensor 105, which detects an actuation or rotation angle of the steering wheel 101 by the driver, electrical signals transmitted by the torque sensor 107, and electrical signals transmitted by various other sensors that are installed in or on the vehicle or associated with it.

[0034] In a Fig. In the illustrated embodiment 1, the angle sensor 105 and the torque sensor 107 are provided as two separate and individual sensors. Alternatively, the angle sensor 105 and the torque sensor 107 can be integrated into a single sensor, such as a torque angle sensor.

[0035] The steering shaft motor 120 may be connected to or associated with a speed reducer configured to reduce the rotational speed of the steering shaft motor 120, including, for example, but not limited to, one or more gears, one or more pulleys and / or one or more belts.

[0036] During normal driving, the steering shaft motor 120 provides the driver with appropriate steering feedback by supplying a reaction force to the steering shaft 103, so that the driver can feel a steering reaction force against the driver's input of the steering wheel 101. The steering shaft motor 120 can also be referred to as a reaction force motor. However, as described below, the steering shaft motor 120 can not only provide the reaction force but also operate according to autonomous steering principles when the steering shaft motor 120 is operating in autonomous driving mode.

[0037] Additionally, the steering shaft motor 120 rotates the steering shaft 103, so that autonomous steering can be carried out under the control of the electronic control unit 110 without the involvement of driving or the intention of the driver when the steering shaft motor 120 is operating in autonomous driving mode.

[0038] Furthermore, in a steer-by-wire steering device, since the steering wheel 101 is not mechanically connected to the rack 130 and a wheel 131, a device for mechanically restricting or limiting a rotation range of the steering wheel 101 may be included to prevent the steering shaft 103 from rotating infinitely when the driver operates the steering wheel 101.

[0039] For example, a rotation angle limiting device 125 may be provided to limit or restrict a rotation range of the steering wheel 101 to prevent the steering shaft 103 from rotating infinitely.

[0040] The first motor 145 and the second motor 147 move the rack 130 or cause the rack 130 to move by means of a rack-and-pinion motion device 140 in order to steer the wheels 131 which are provided or connected to two opposite sides of the rack 130 by means of tie rods 133 and kingpin arms 135 by moving the rack 130.

[0041] The rack and pinion motion device 140 comprises the ball nut 141, the first nut pulley 143a, the second nut pulley 143b, the first motor pulley 142a, and the second motor pulley 142b. The ball nut 141 can be rotatably coupled to the rack 130 by means of the balls 144 and configured to displace the rack 130 in the axial direction of the rack and pinion motion device 140 by rotating the ball nut 141. The first nut pulley 143a can be provided on one side of the outer circumferential surface of the ball nut 141, and the second nut pulley 143b can be provided on the other side of the outer circumferential surface of the ball nut 141. The first motor pulley 142a can be coupled to the first motor 145 (e.g.,The first motor pulley 142b can be coupled to the second motor 147 (e.g., attached to a shaft of the first motor 145) or formed directly on a rotatable part of the first motor 145 and connected to the first nut pulley 143a by the first belt 149a. The second motor pulley 142b can be coupled to the second motor 147 (e.g., attached to a shaft of the second motor 147) or formed directly on a rotatable part of the second motor 147 and connected to the second nut pulley 143b by the second belt 149a.

[0042] Furthermore, the balls 144 are rotatably arranged between a rack screw groove formed on an outer circumferential surface of the rack 130 and a nut screw groove formed on an inner circumferential surface of the ball nut 141, so that the rack 130 can be moved in the axial direction of the rack motion device 140 by the rotation of the ball nut 141.

[0043] In the embodiments of the present disclosure described above, however, the angle sensor 105 and the torque sensor 107 are provided on or around the steering shaft 103, and the steering device according to one embodiment of the present disclosure may include a vehicle speed sensor 102, an ultrasonic sensor 104, and an image sensor 106 for transmitting steering information to the electronic control unit 110. Various types of sensors, such as radar and lidar, may also be added to an embodiment of the present disclosure.

[0044] In a steer-by-wire steering device, since the steering wheel 101 is not mechanically connected to the rack 130 and the wheel 131, a device for mechanically limiting the rack 130 may be included to prevent the rack 130 from rotating due to a torque of the ball nut 141, which is rotated by the rack motion device 140.

[0045] For example, a rotation prevention element 150 is configured to support the axial displacement of the rack 130 and to prevent the rotation of the rack 130.

[0046] In a Fig. In the illustrated embodiment, a single anti-rotation element 150 is provided on one side of the rack 130. Alternatively, a plurality of anti-rotation elements 150 can be provided to support the rack 130. The number of anti-rotation elements 150, the axial position of the anti-rotation element 150, or the like can vary depending on the configuration and required operation of the first and second motors 145 and 147 and the required torque of the ball nut 141 of the rack motion device 140.

[0047] In a Fig. In the illustrated embodiment, the first motor 145 and the second motor 147 are arranged such that they face each other, so that a shaft 145a of the first motor 145 and a shaft 147a of the second motor 147 are aligned coaxially and arranged parallel to a central axis of the rack 130.

[0048] In another in Fig. In the illustrated embodiment 2, the first motor 145 is arranged on one side of the rack 130 and the second motor 147 is arranged on the other side of the rack 130, so that the rack 130 is positioned between the shaft 145a of the first motor 145 and the shaft 147a of the second motor 147, and the shaft 145a of the first motor 145 and the shaft 147a of the second motor 147 are arranged parallel to the central axis of the rack 130 and are located on two opposite sides of the central axis of the rack 130.

[0049] As described above, the exemplary arrangements of the first and second motors 145 and 147 and the rack 130, which are shown in Fig. 1 and Fig. 2 are illustrated, reducing the package size of the steering device, which makes it more compact in volume, and simplifying the process of assembling the steering device, the first motor 145, the first belt 149a, the second motor 147 and the second belt 149b.

[0050] With reference to Fig. 3. The outer diameter mD1 of the first motor pulley 142a and the outer diameter mD2 of the second motor pulley 142b can be different from each other, and the outer diameter nD1 of the first mother pulley 143a and the outer diameter nD2 of the second mother pulley 143b can be the same.

[0051] This means that the first nut pulley 143a and the second nut pulley 143b rotate while maintaining the same phase angle without a phase difference between them when the first motor 145 and the second motor 147 are operating. The first motor pulley 142a and the second motor pulley 142b rotate while a phase difference between them gradually changes when the first motor 145 and the second motor 147 are operating.

[0052] In a Fig. In the illustrated embodiment 3, the first nut pulley 143a and the second nut pulley 143b are provided separately and connected to one section and the other section of the outer circumferential surface of the ball nut 141. However, as shown in Fig. Figure 4 illustrates that the first nut pulley 143a and the second nut pulley 143b are integrated as a single piece with the same outer diameter. This is described below.

[0053] The first motor 145 can have a first motor sensor 145s configured to detect a rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have a second motor sensor 147s configured to detect a rotational position of the shaft 147a of the second motor 147.

[0054] When the first motor 145 is operating, the first motor sensor 145s detects a direction and angle of rotation of the shaft 145a of the first motor 145, and the first motor sensor 145s outputs a signal indicating the direction and angle to the electronic control unit 110.

[0055] When the second motor 147 is operating, the second motor sensor 147s detects the direction and angle of rotation of the shaft 147a of the second motor 147, and the second motor sensor 147s outputs a signal indicating the direction and angle of rotation of the shaft 147a of the second motor 147 to the electronic control unit 110.

[0056] Therefore, the electronic control unit 110 can determine a linear position of the rack 130 based on a first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and a second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s, and output a control signal to the first motor 145 and the second motor 147.

[0057] This means that the electronic control unit 110 sets an angle between a reference point on the shaft 145a of the first motor 145 when the first motor 145 is stopped and a reference point on the shaft 147a of the second motor 147 when the second motor 147 is stopped, to a reference position value. The electronic control unit 10 sets an angle between the reference point on the shaft 145a of the first motor 145 and the reference point on the shaft 147a of the second motor 147 after the first and second motors 145 and 147 have been operated, to an operating position value. The electronic control unit 10 determines the linear position of the rack 130 based on the difference between the reference position value and the operating position value.

[0058] For example, the difference between the reference position value and the operating position value can be set from 0° to 360°. A maximum displacement of the rack 130 is set within this range. The electronic control unit 110 determines the displacement position of the rack 130 based on at least one of the following: a rotation ratio between the first motor pulley 142a and the first nut pulley 143a, a rotation ratio between the second motor pulley 142b and the second nut pulley 143b, an outer diameter and an inner diameter of the ball nut 141, an outer diameter of the rack 130, or a helix angle between the rack bolt groove and the nut bolt groove.

[0059] Additionally, the electronic control unit 110 can determine the linear position of the rack 130 by setting the difference between the reference position value and the operating position value to a motion value and comparing the motion value with preset data. For example, the motion value can be set from 0° to 360°, and the maximum displacement of the rack 130 can be set within this range.

[0060] The preset data can be data that includes the displacement amount of the rack 130, which corresponds to the movement value determined on the basis of at least one of the outer diameters of the first and second motor pulleys 142a and 142b, the outer diameters of the first and second nut pulleys 143a and 143b, the outer and inner diameters of the ball nut 141 and / or the outer diameter of the rack 130.

[0061] For example, the first motor pulley 142a and the second motor pulley 142b have different outer diameters, and the first nut pulley 143a and the second nut pulley 143b have the same outer diameter, so that the electronic control unit 110 can determine the displacement position of the rack 130 based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s, and output a signal to control the first motor 145 and the second motor 147.

[0062] With reference to Fig. 4. The first nut pulley 143a and the second nut pulley 143b can be integrated into a single piece with the same outer diameter.

[0063] In an example where the first mother pulley 143a and the second mother pulley 143b are integrated into a single piece with the same outer diameter, the first belt 149a is coupled to one section of the integrated pulley, and the second belt 149b is coupled to the other section of the integrated pulley, so that the first belt 149a and the second belt 149b can each be connected to the first motor pulley 142a and the second motor pulley 142b, respectively.

[0064] Furthermore, the first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0065] When the first motor 145 is operating, the first motor sensor 145s detects the direction and angle of rotation of the shaft 145a of the first motor 145, and the first motor sensor 145s transmits the direction and angle to the electronic control unit 110.

[0066] When the second motor 147 is operating, the second motor sensor 147s detects the direction and angle of rotation of the shaft 147a of the second motor 147, and the second motor sensor 147s transmits a signal indicating the direction and angle to the electronic control unit 110.

[0067] Therefore, the electronic control unit 110 can determine the linear position of the rack 130 based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s, and output a signal to control the first motor 145 and the second motor 147.

[0068] In an exemplary embodiment, which is described in Fig. As illustrated in Figure 5, the outer diameter mD1 of the first motor pulley 142a and the outer diameter mD2 of the second motor pulley 142b can be the same, and the outer diameter nD1 of the first mother pulley 143a and the outer diameter nD2 of the second mother pulley 143b can be different.

[0069] The first nut pulley 143a, the second nut pulley 143b, and the ball nut 141 rotate at the same speed. Therefore, the first nut pulley 143a and the second nut pulley 143b maintain the same phase angle and rotate without a phase difference when the first motor 145 and the second motor 147 are operating. However, the first motor pulley 142a and the second motor pulley 142b rotate with a gradually changing phase difference.

[0070] Furthermore, the first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0071] When the first motor 145 is operating, the first motor sensor 145s detects the direction and angle of rotation of the shaft 145a of the first motor 145, and the first motor sensor 145s outputs a signal indicating the direction and angle of rotation of the shaft 145a of the first motor 145 to the electronic control unit 110.

[0072] Furthermore, when the second motor 147 is operating, the second motor sensor 147s detects the direction and rotation angle of the shaft 147a of the second motor 147, and the second motor sensor 147s transmits the direction and rotation angle of the shaft 147a of the second motor 147 to the electronic control unit 110.

[0073] Therefore, the electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the linear position of the rack 130 by the above-mentioned determination process based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s.

[0074] In an exemplary embodiment, which is described in Fig. As shown in Figure 6, the outer diameter mD1 of the first motor pulley 142a and the outer diameter mD2 of the second motor pulley 142b can be different from each other, and the outer diameter nD1 of the first mother pulley 143a and the outer diameter nD2 of the second mother pulley 143b can also be different from each other.

[0075] Even in this case, the first nut pulley 143a, the second nut pulley 143b, and the ball nut 141 rotate at the same speed. Therefore, the first nut pulley 143a and the second nut pulley 143b maintain the same phase angle and rotate without a phase difference when the first motor 145 and the second motor 147 are operating.

[0076] Furthermore, the first motor pulley 142a and the second motor pulley 142b rotate while a phase difference is gradually changed when the first motor 145 and the second motor 147 are operating.

[0077] The first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0078] Therefore, the electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the linear position of the rack 130 by the above-mentioned determination process based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s.

[0079] In an exemplary embodiment of Fig. 7. First motor pulley teeth 142-1 are provided on an outer circumferential surface of the first motor pulley 142a, and first nut pulley teeth 143-1 are provided on an outer circumferential surface of the first nut pulley 143a. The first motor pulley teeth 142-1 and the first nut pulley teeth 143-1 can be coupled to first belt teeth 149-1, which are provided on an inner circumferential surface of the first belt 149a.

[0080] Since the first engine pulley teeth 142-1 and the first nut pulley teeth 143-1 are coupled with the first belt teeth 149-1 to transmit power, the first engine pulley teeth 142-1 and the first nut pulley teeth 143-1 are the same size as the first belt teeth 149-1.

[0081] Second motor pulley teeth 142-2 are provided on an outer circumferential surface of the second motor pulley 142b, and second nut pulley teeth 143-2 are provided on an outer circumferential surface of the second nut pulley 143b. The second motor pulley teeth 142-2 and the second nut pulley teeth 143-2 can be coupled to second belt teeth 149-2, which are provided on an inner circumferential surface of the second belt 149b.

[0082] Since the second motor pulley teeth 142-2 and the second nut pulley teeth 143-2 are coupled with the second belt teeth 149-2 to transmit power, the second motor pulley teeth 142-2 and the second nut pulley teeth 143-2 can be the same size as the second belt teeth 149-2.

[0083] Furthermore, the number of teeth on the first motor pulley 142-1 and the number of teeth on the second motor pulley 142-2 can be different, and the number of teeth on the first nut pulley 143-1 and the number of teeth on the second nut pulley 143-2 can be the same.

[0084] The first motor pulley teeth 142-1 and the second motor pulley teeth 142-2 have the same circumferential pitch, different pitch circle diameters, and a different number of teeth. The first nut pulley teeth 143-1 and the second nut pulley teeth 143-2 have the same circumferential pitch, the same pitch circle diameter, and a different number of teeth.

[0085] The first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0086] Therefore, the electronic control unit 110 can determine the linear position of the rack 130 based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s, and output a signal to control the first motor 145 and the second motor 147.

[0087] This means that, as in the determination method mentioned above, the difference between the reference position value and the operating position value can be set from 0° to 360°, and the maximum displacement of the rack 130 is set within this range. The electronic control unit 110 determines the displacement position of the rack 130 based on at least one of the following: a pitch circle diameter ratio or a tooth number ratio between the first motor pulley 142a and the first nut pulley 143a, a pitch circle diameter ratio or a tooth number ratio between the second motor pulley 142b and the second nut pulley 143b, the outer and inner diameters of the ball nut 141, or the outer diameter of the rack 130.

[0088] Additionally, similar to the determination method mentioned above, the electronic control unit 110 can determine the displacement position of the rack 130 by setting the difference between the reference position value and the operating position value to the movement value and comparing the movement value with preset data. In this case, the movement value can be set from 0° to 360°, and the maximum displacement of the rack 130 is set within this range.

[0089] In this case, the preset data can be data that includes the displacement amount of the rack 130, which corresponds to the movement value determined on the basis of at least one of the pitch circle diameters and the number of teeth of the first and second motor pulleys 142a and 142b, the pitch circle diameters and the number of teeth of the first and second nut pulleys 143a and 143b, the outer and inner diameters of the ball nut 141 and / or the outer diameter of the rack 130.

[0090] As described above, the number of teeth on the first motor pulley 142-1 and the number of teeth on the second motor pulley 142-2 are different, while the number of teeth on the first nut pulley 143-1 and the number of teeth on the second nut pulley 143-2 are the same. The electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the displacement position of the rack 130 based on the first position of the shaft 145a of the first motor 145, detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, detected by the second motor sensor 147s.

[0091] Additionally, the number of teeth on the first motor pulley 142-1 and the number of teeth on the second motor pulley 142-2 can be the same, and the number of teeth on the first nut pulley 143-1 and the number of teeth on the second nut pulley 143-2 can be different.

[0092] The first motor pulley teeth 142-1 and the second motor pulley teeth 142-2 have the same circumferential pitch, the same pitch circle diameter, and the same number of teeth. The first nut pulley teeth 143-1 and the second nut pulley teeth 143-2 have the same circumferential pitch but different pitch circle diameters and different numbers of teeth.

[0093] Furthermore, the first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0094] Therefore, the electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the displacement position of the rack 130 by the above-mentioned determination process based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s.

[0095] Additionally, the number of teeth on the first motor pulley 142-1 and the number of teeth on the second motor pulley 142-2 may be different, and the number of teeth on the first nut pulley 143-1 and the number of teeth on the second nut pulley 143-2 may be different.

[0096] This means that the first motor pulley teeth 142-1 and the second motor pulley teeth 142-2 can have the same circumferential pitch but different pitch circle diameters and a different number of teeth. Similarly, the first nut pulley teeth 143-1 and the second nut pulley teeth 143-2 have the same circumferential pitch but different pitch circle diameters and a different number of teeth.

[0097] Furthermore, the first motor 145 can have the first motor sensor 145s, which is configured to detect the rotational position of the shaft 145a of the first motor 145, and the second motor 147 can have the second motor sensor 147s, which is configured to detect the rotational position of the shaft 147a of the second motor 147.

[0098] Therefore, the electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the displacement position of the rack 130 by the above-mentioned determination process based on the first position of the shaft 145a of the first motor 145, which is detected by the first motor sensor 145s, and the second position of the shaft 147a of the second motor 147, which is detected by the second motor sensor 147s.

[0099] In an exemplary embodiment of Fig. 8 To prepare for a case in which one of the first motor sensor 145s and the second motor sensor 147s is not functional, a rotary gear 139, rotatably engaged with a rack thread 130b provided on the rack 130, can be rotatably coupled to the rack 130, and a rotary angle sensor 137s can be configured to detect a rotary angle of the rotary gear 139.

[0100] The rotary gear 139 can be configured to rotate while supported on a rack housing by means of a bearing. The rotation angle sensor 137s can be installed on or around a shaft 137 of the rotary gear 139 and configured to detect a rotation angle of the rotary gear 139 and transmit the rotation angle of the rotary gear 139 to the electronic control unit 110.

[0101] Therefore, even if one of the first motor sensor 145s and the second motor sensor 147s is not functional, the electronic control unit 110 can output a signal to control the first motor 145 and the second motor 147 by determining the displacement position of the rack 130 based on the pre-stored transmission ratio between the rack thread 130b and the rotary gear 139 and the rotation angle of the rotary gear 139 received from the rotation angle sensor 137s.

[0102] Furthermore, various embodiments of a rotation prevention element or means in the steering device mentioned above can be provided below.

[0103] Some embodiments of the anti-rotation element 150 are described in more detail below with reference to Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17 to Fig. 18 described.

[0104] As in Fig. As illustrated in Figure 9, the anti-rotation element 150 can be coupled to one radial side and the other radial side of the rack 130 and support two opposite sides of the rack 130, thus preventing the rack 130 from rotating.

[0105] The anti-rotation element 150 can include a shaft 230 configured to support a support surface 130-1 formed on the outer circumferential surface of the rack 130, and a support yoke 240 configured to support the outer circumferential surface of the rack 130 opposite or corresponding to a position where the shaft 230 is supported.

[0106] The support surface 130-1, which is formed on the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0107] The support surface 130-1 can be recessed from the outer circumferential surface of the rack 130 and can be designed as a curved surface, a flat surface or a combination thereof.

[0108] The support surface 130-1 extends in an axial direction of the rack 130 in order to be supported by the shaft 230 when the rack 130 moves in the axial direction of the rack 130.

[0109] Optionally, a coating layer can be provided on the support surface 130-1 and made of a low-friction material with a low coefficient of friction, such as fluorinated resin or ceramic, to minimize or reduce friction with the shaft 230.

[0110] The shaft 230, which supports the support surface 130-1 of the rack 130, can include an upper end support section 231, a body section 233 and a lower end support section 235.

[0111] When the rack 130 moves, the shaft 230 is held in place by a rack housing (e.g. 160 made of Fig. 10) supported and is configured to be rotatable, so that the body section 233 supports the support surface 130-1 of the rack 130, thereby preventing the rack 130 from rotating.

[0112] A needle bearing 236 can be coupled to the body section 233 to minimize or reduce friction with the support surface 130-1 of the rack 130.

[0113] The upper end support section 231, which has a larger diameter than the body section 233, can be provided above the body section 233, and an upper end bearing 234 can be coupled to the upper end support section 231 to be rotatably supported on the rack housing.

[0114] An upper plug 232 can be coupled to a top surface of the upper end support section 231 to prevent foreign substances from being introduced into the rack housing.

[0115] The lower end support section 235, which has a smaller diameter than the body section 233, can be provided below the body section 233, and a lower end bearing 238 can be coupled to the lower end support section 235 to be rotatably supported on the rack housing.

[0116] The support yoke 240, which supports the outer circumferential surface of the rack 130 opposite a position where the shaft 230 is supported, supports the rack 130 in the direction of the shaft 230 when the rack 130 moves, thus preventing the rack 130 from rotating.

[0117] A support section 241 with a curved surface can be formed at an end section of the support yoke 240 and can be supported on the outer circumferential surface of the rack 130, making close contact with it. The support section 241 with a curved surface can have a curved surface that is identical to the outer circumferential surface of the rack 130.

[0118] The support yoke 240 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0119] An elastic ring 245 can be coupled to an outer circumferential surface of the support yoke 240 to prevent rattling noises with the rack housing.

[0120] One or more elastic rings 245 can be coupled to the outer circumferential surface of the support yoke 240.

[0121] The elastic ring 245 can be made of a material capable of absorbing vibrations and noise and exhibiting predetermined elasticity and stiffness. For example, the elastic ring 245 can be made of one or more materials selected from a group consisting of natural rubber (NR), nitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), fluororubber (FPM), styrene butadiene rubber (SBR), chlorosulfonated polyethylene (CSM), urethane, and silicone, all of which possess the aforementioned properties.

[0122] A yoke plug 243 can be coupled to an end section of the support yoke 240, press-fitted or screwed to the rack housing and fix the support yoke 240.

[0123] Furthermore, an elastic body can be coupled between the support yoke 240 and the yoke plug 243 and elastically support the support yoke 240 in the direction of the rack 130.

[0124] As in Fig. As illustrated in Figure 10, the anti-rotation element 150 can be coupled to one radial side and the other radial side of the rack 130 and support two opposite sides of the rack 130, thus preventing the rack 130 from rotating.

[0125] The anti-rotation element 150 can include a needle bearing 220 configured to support the support surface 130-1 formed on the outer circumferential surface of the rack 130, a support yoke 225 rotatably coupled to the needle bearing 220, and a rack bushing 229 configured to support the outer circumferential surface of the rack 130 opposite a position where the needle bearing 220 is supported.

[0126] The support surface 130-1 can be formed on the outer circumferential surface of the rack 130. For example, the support surface 130-1 can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0127] The support surface 130-1 can be recessed into the outer circumferential surface of the rack 130. The support surface 130-1 can be designed as a curved surface or a flat surface.

[0128] The support surface 130-1 extends longitudinally in the axial direction of the rack 130. And the support surface 130-1 can be supported by the needle bearing 220 when the rack 130 moves in the axial direction of the rack 130.

[0129] A coating layer can be provided on the support surface 130-1 and made of a low-friction material, such as fluorinated resin or ceramic, to minimize or reduce friction with the needle bearing 220.

[0130] The needle bearing 220 can be configured to support the support surface 130-1 of the rack 130, the needle bearing 220 can have a support shaft 221 provided on a central section of the needle bearing 220, and the support shaft 221 is attached to the support yoke 225 so that the needle bearing 220 can be rotatably supported by the support yoke 225.

[0131] An outer ring 222 of the needle bearing 220 is supported on the support surface 130-1 and is configured to rotate when the rack 130 moves, in order to prevent the rack 130 from rotating.

[0132] The outer ring 222 of the needle bearing 220 can be arranged in a position that projects from an end section of the support yoke 225, so that the outer ring 222 can be supported on the support surface 130-1.

[0133] The support yoke 225 supports the needle bearing 220 in the direction of the support surface 130-1 when the rack 130 moves, in order to prevent the rack 130 from rotating.

[0134] The support yoke 225 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0135] An elastic ring 226 can be coupled to the outer circumferential surface of the support yoke 225 to prevent rattling noises with the rack housing 160.

[0136] One or more elastic rings 226 can be coupled to the outer circumferential surface of the support yoke 225.

[0137] The elastic ring 226 can be made of a material capable of absorbing vibrations and noise and exhibiting predetermined elasticity and stiffness. Therefore, the elastic ring 226 can be made of one or more materials selected from a group consisting of natural rubber (NR), nitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), fluororubber (FPM), styrene butadiene rubber (SBR), chlorosulfonated polyethylene (CSM), urethane, and silicone, all of which possess the aforementioned properties.

[0138] A yoke plug 227 can be coupled to one end of the support yoke 225, press-fitted or screwed to the rack housing 160, and configured to fix the position of the support yoke 225.

[0139] Furthermore, an elastic body 228 can be coupled between the support yoke 225 and the yoke plug 227 and elastically support the support yoke 225 by exerting an elastic force in the direction of the rack 130.

[0140] The rack bushing 229, which supports the outer circumferential surface of the rack 130 against another outer circumferential surface of the rack 130, which supports the needle bearing 220, can be formed in a semi-cylindrical shape, which is produced by cutting a part of an outer circumferential surface thereof.

[0141] The rack bushing 229 supports the rack 130 in the direction of the needle bearing 220 in the radial direction of the rack bushing 229 when the rack 130 moves, thus preventing the rack 130 from rotating.

[0142] The rack bushing 229 can have a curved surface that is identical to or corresponds to the outer circumferential surface of the rack 130, so that it is in close contact with and supported on the outer circumferential surface of the rack 130.

[0143] A bushing coupling groove 166-1, with which the rack bushing 229 is coupled, can be formed on an inner circumferential surface of the rack housing 160.

[0144] The rack bushing 229 can have a fastening projection 229a formed on or around an end section of an outer circumferential surface of the rack bushing 229 to prevent the axial position of the rack bushing 229 from being separated or rotated when the rack 130 moves.

[0145] A fastening groove 166-2 can be formed on the inner circumferential surface of the rack housing 160, and the fastening projection 229a of the rack bushing 229 can be coupled to the fastening groove 166-2 of the rack housing 160.

[0146] The rack bushing 229 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0147] In a Fig. In the illustrated embodiment 11, the anti-rotation element 150 can be configured to prevent the rack 130 from rotating about its central axis. The anti-rotation element 150 supports the outer circumferential surface of the rack 130 and can also be supported on the inner circumferential surface of the rack housing 160.

[0148] The anti-rotation element 150 can include a support element 210, one end section of which is arranged or supported in a rack support groove 132 formed on the outer circumferential surface of the rack 130, and the other end section of which is arranged or supported in a housing groove 162 formed on the inner circumferential surface of the rack housing 160, and an elastic element 212 coupled to the support element 210 and configured to elastically support the inner circumferential surface of the rack housing 160.

[0149] The rack support groove 132, which is formed on the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0150] The rack support groove 132 can be recessed into the outer circumferential surface of the rack 130. The rack support groove 132 can have a curved surface or a flat surface.

[0151] The rack support groove 132 can extend longitudinally in the axial direction of the rack 130 and be supported by the support element 210 when the rack 130 moves in the axial direction of the rack 130.

[0152] A coating layer can be provided on the rack support groove 132 and made of a low-friction material, such as fluoropolymer or ceramic, to reduce or minimize friction with the support element 210.

[0153] The housing groove 162, in which the other end section of the support element 210 is supported, can be formed in a position that faces the rack support groove 132 in the radial direction of the rack 130.

[0154] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0155] The housing groove 162 can be recessed into the inner circumferential surface of the rack housing 160 and have a curved surface or a flat surface, so that the support element 210 can prevent the rotation of the rack 130 when the rack 130 moves in the axial direction of the rack 130.

[0156] One end section and the other end section of the support element 210 are coupled to the rack support groove 132 and the housing groove 162 respectively, and a coupling groove 211, with which the elastic element 212 is coupled, is formed on the other end section of the support element 210.

[0157] The support element 210 can have a predetermined stiffness and elasticity and can be made of one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0158] The elastic element 212 is coupled to the coupling groove 211 of the support element 210, supports the support element 210, and is configured to exert an elastic force in the direction of the rack 130 while being elastically supported on the inner circumferential surface of the rack housing 160. This ensures that the support element 210 maintains a predetermined distance to avoid colliding with the inner circumferential surface of the rack housing 160 when the rack 130 moves axially. Therefore, rattling noises between the support element 210 and the rack housing 160 are prevented.

[0159] For example, the elastic element 212 can be designed as a curved thin plate.

[0160] A plug bolt 215 can be arranged at an axial end of the support element 210, can be configured to prevent separation of the support element 210, and can be coupled to the inner circumferential surface of the rack housing 160. For example, the plug bolt 215 can be press-fitted and coupled to the inner circumferential surface of the rack housing 160.

[0161] The plug bolt 215 includes a support section 215a, which is configured to support the support element 210 in the axial direction of the rack 130, and a fixing section 215b, which extends from the support section 215a and is fixed to the inner circumferential surface of the rack housing 160.

[0162] The outer circumferential surface of the fixing section 215b has a threaded section which is screwed to the inner circumferential surface of the rack housing 160.

[0163] Furthermore, a fixing element 217 can be coupled to an axial end of the plug bolt 215 to prevent the plug bolt 215 from being loosened and separated.

[0164] A fixing projection 217a, which projects in the radial direction of the rack housing 160, can project from an outer circumferential surface of the fixing element 217.

[0165] A fixing groove 164 can be formed on the inner circumferential surface of the rack housing 160, and the fixing projection 217a of the fixing element 217 can be inserted into the fixing groove 164 and supported by it.

[0166] In one embodiment of Fig. 12 The anti-rotation element 150 can be supported on the outer circumferential surface of the rack 130 and the inner circumferential surface of the rack housing and prevent the rack 130 from rotating about the central axis.

[0167] The anti-rotation element 150 can include a support bushing 205 configured to support the support surface 130-1 formed on the outer circumferential surface of the rack 130, a bushing holder 200 coupled to the outer circumferential surface of the rack 130 and having an inner circumferential surface on which the support bushing 205 is supported, and an elastic element 207 coupled between the bushing holder 200 and the support bushing 205 and configured to elastically support the support bushing 205 by exerting an elastic force in the direction of the rack 130.

[0168] For example, the support surface 130-1, which is formed on the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0169] The support surface 130-1 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0170] The support surface 130-1 extends longitudinally in the axial direction of the rack 130 and is supported by the support bushing 205 when the rack 130 moves in the axial direction.

[0171] A coating layer can be provided on the support surface 130-1 and made of a low-friction material, such as fluoropolymer or ceramic, to minimize or reduce friction with the support bushing 205.

[0172] The housing groove 162, with which the bushing holder 200 is coupled and in which it is supported, is formed on the inner circumferential surface of the rack housing 160 and is positioned so that it faces the support surface 130-1 in the radial direction of the rack 130.

[0173] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0174] The housing groove 162 can be recessed from the inner circumferential surface of the rack housing 160 and can have a curved surface or a flat surface.

[0175] Additionally, a stepped projection section 163 with a larger diameter can be formed at an end section of the housing groove 162 on the inner circumferential surface of the rack housing 160, and an end section of the stepped projection section 163 can have an opening in the axial direction of the rack 130.

[0176] The bushing holder 200 has a cylindrical shape. For example, the bushing holder 200 can have a cut-out section, which is produced by cutting a radial side of the bushing holder 200, and a projecting inner circumferential surface 201 that projects radially inwards.

[0177] Furthermore, a bushing coupling groove 203, with which the support bushing 205 is coupled, can be formed on the projecting inner circumferential surface 201. A flange section 206, which projects radially, is supported by or on the stepped projection section 163 of the rack housing 160 and can be formed at an axial end of the bushing holder 200.

[0178] The flange section 206 is supported by or on the stepped projection section 163 to prevent the bushing holder 200 from separating when the rack 130 moves in the axial direction.

[0179] The support bushing 205, which is coupled to the bushing coupling groove 203 of the bushing holder 200, includes a projecting support section 205a that projects from a central section of the support bushing 205, and the elastic element 207 is coupled to the projecting support section 205a.

[0180] For example, the elastic element 207 can be formed in a ring shape and in a conical shape, in which an inner circumferential surface and an outer circumferential surface of the elastic element 207 are stepped in the axial direction, so that the protruding support section 205a can be coupled to an inner circumferential surface of the elastic element 207.

[0181] The elastic element 207 elastically supports the support bushing 205 to exert an elastic force in the direction of the rack 130, and the elastic element 207 can be positioned between the bushing holder 200 and the support bushing 205, forming a gap or space 202 so that the support bushing 205 cannot collide with the bushing holder 200 when the rack 130 moves in the axial direction, in order to prevent or reduce rattling noises between the support bushing 205 and the bushing holder 200.

[0182] The bushing holder 200 and the support bushing 205 can have a predetermined stiffness and elasticity and can be made of one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0183] In one embodiment of Fig. 13 The anti-rotation element 150 can support the outer circumferential surface of the rack 130 to prevent the rack 130 from rotating about the central axis of the anti-rotation element 150, and can be supported by the inner circumferential surface of the rack housing 160.

[0184] The anti-rotation element 150 can include a rack bushing 250, comprising an inner circumferential support section 251, which is inserted into and supported by the rack support groove 132 formed on the outer circumferential surface of the rack 130, and an outer circumferential support section 253, which is inserted into and supported by the housing groove 162 formed on the inner circumferential surface of the rack housing 160, and an elastic element 252, which is coupled to the outer circumferential surface of the rack bushing 250 and is configured to elastically support the rack bushing 250.

[0185] For example, the rack support groove 132, which is formed on the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0186] The rack support groove 132 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0187] The rack support groove 132 extends longitudinally in the axial direction of the rack 130 in order to be supported by the rack bushing 250 when the rack 130 moves in the axial direction.

[0188] A coating layer can be provided on the rack support groove 132 and made of a low-friction material, such as fluoropolymer or ceramic, to minimize or reduce friction with the rack bushing 250.

[0189] The inner circumferential support section 251 projects radially inwards from the inner circumferential surface of the rack bushing 250 at a position facing the rack support groove 132.

[0190] The outer circumferential support section 253 projects radially outwards from the outer circumferential surface of the rack bushing 250 and is coupled to the housing groove 162.

[0191] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0192] The housing groove 162 can be recessed from the inner circumferential surface of the rack housing 160 and can have a curved surface or a flat surface.

[0193] Two or more outer circumferential support sections 253 can be formed on the outer circumferential surface of the rack bushing 250 and be spaced apart from each other in a circumferential direction.

[0194] For example, a pair of outer circumferential support sections 253 can be formed on the outer circumferential surface of the rack bushing 250 in the circumferential direction at a position corresponding to the inner circumferential support section 251.

[0195] The rack bushing 250 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0196] The elastic element 252 can be coupled to the outer circumferential surface of the rack bushing 250 and can have a ring shape.

[0197] The elastic element 252 can be made of a material capable of absorbing vibrations and noise and exhibiting predetermined elasticity and stiffness. Therefore, the elastic element 252 can be made of one or more materials selected from a group consisting of natural rubber (NR), nitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), fluororubber (FPM), styrene butadiene rubber (SBR), chlorosulfonated polyethylene (CSM), urethane, and silicone, all of which possess the aforementioned properties.

[0198] A coupling groove 252-1, with which the elastic element 252 is coupled, can be formed on the outer circumferential surface of the rack bushing 250.

[0199] The rack bushing 250 can have a cut-out section 254 that is cut in the axial direction, so that the rack bushing 250 is deformable in the radial direction.

[0200] Two or more cut-out sections 254, spaced apart from each other in the circumferential direction, may be provided.

[0201] The cut-out sections 254 can be designed such that one end or the other end of the rack bushing 250 is open at a position where the cut-out section 254 is formed.

[0202] The cut-out sections 254, which are open at one end of the rack bushing 250, and the cut-out section 254, which is open at the other end of the rack bushing 250, can be spaced apart from each other in the circumferential direction and formed in an offset manner.

[0203] Therefore, the rack bushing 250 is elastically supported in the radial direction by an elastic force of the elastic element 252, so that the rack bushing 250 cannot collide with the rack housing 160 when the rack 130 moves in the axial direction, in order to prevent or reduce rattling noises between the rack bushing 250 and the rack housing 160.

[0204] In a Fig. In the illustrated embodiment 14, the anti-rotation element 150 can support the outer circumferential surface of the rack 130 to prevent the rack 130 from rotating about the central axis of the rack 130, and can be supported by the inner circumferential surface of the rack housing 160.

[0205] The anti-rotation element 150 can include a rotary element 191 configured to support the support surface 130-1 formed on the outer circumferential surface of the rack 130, and a support bushing 190 coupled to the housing groove 162 formed on the inner circumferential surface of the rack housing 160, and configured such that the rotary element 191 is rotatably coupled to the support bushing 190.

[0206] For example, the support surface 130-1, which is formed on the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0207] The support surface 130-1 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0208] The support surface 130-1 extends longitudinally in the axial direction of the rack 130 in order to be supported by the rotary element 191 when the rack 130 moves in the axial direction.

[0209] Two or more support surfaces 130-1 can be formed on the outer circumferential surface of the rack 130 and be spaced apart from each other in the circumferential direction of the rack 130.

[0210] For example, a pair of support surfaces 130-1 can be formed on opposite sides of the rack 130 with respect to the center of the rack 130.

[0211] The rotating elements 191 can be configured as a roller or ball that is movably arranged in an inner surface of the support bushing 190 (e.g. within one or more elongated holes of the support bushing 190) and is configured to be rotatable or rollable while supported on the support surface 130-1 of the rack 130.

[0212] The rotating elements 191 can be rotatably supported on both the inner and outer surfaces of the support bushing 190.

[0213] A coating layer can be provided on the support surface 130-1 and made of a low-friction material, such as fluoropolymer or ceramic, to reduce or minimize friction with the rotating element 191.

[0214] The housing groove 162, in which the support bushing 190 is arranged, is formed on the inner circumferential surface of the rack housing 160 at a position that faces a support surface 130-1 of the rotating element 191 in the radial direction.

[0215] The support bushing 190 is coupled to the housing groove 162 of the rack housing 160, and the rotary element 191 is rotatably coupled to the support bushing 190.

[0216] The support bushing 190 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0217] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0218] The housing groove 162 can be recessed from the inner circumferential surface of the rack housing 160 and can have a curved surface or a flat surface.

[0219] In a Fig. In the illustrated embodiment 15, the anti-rotation element 150 can support the outer circumferential surface of the rack 130 to prevent the rack 130 from rotating about the central axis and is supported by the inner circumferential surface of the rack housing.

[0220] The anti-rotation element 150 can include a rack bushing 180, which includes one or more rotation support sections 183 rotatably arranged between the rack support groove 132 formed on the outer circumferential surface of the rack 130 and the housing groove 162 formed on the inner circumferential surface of the rack housing 160, an elastic support section 185 arranged between the rack support groove 132 formed on the outer circumferential surface of the rack 130 and the housing groove 162 formed on the inner circumferential surface of the rack housing 160 and elastically supported by it, and a connecting section 181 connecting the rotation support section 183 and the elastic support section 185.

[0221] The rack support groove 132 can be formed on the outer circumferential surface of the rack 130. For example, the rack support groove 132 can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0222] The rack support groove 132 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0223] The rack support groove 132 extends longitudinally in the axial direction of the rack 130 and is supported by the rotary support section 183 and the elastic support section 185 when the rack 130 moves axially. The rotary support section 183 and the elastic support section 185 can be arranged in the rack support groove 132.

[0224] The housing groove 162 is formed on the inner circumferential surface of the rack housing 160 at the position that faces or corresponds to the rack support groove 132 in the radial direction.

[0225] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0226] The housing groove 162 can be recessed from the inner circumferential surface of the rack housing 160 and can have a curved surface or a flat surface.

[0227] A coating layer can be provided on the rack support groove 132 and the housing groove 162 and can be made of a low-friction material, such as fluoropolymer or ceramic, to minimize or reduce friction with the rack bushing 180.

[0228] The rack bushing 180 can have two or more rotary support sections 183 and / or two or more elastic support sections 185.

[0229] Balls can be coupled to the rotary support sections 183, and the balls can be spaced apart from each other in the axial direction.

[0230] The elastic support section 185 can have a substantially cylindrical shape. The elastic support section 185 can have an opening on one side.

[0231] The rack bushing 180 is elastically supported by the rack support groove 132 and the housing groove 162 by an elastic deformation force of the elastic support section 185, thereby maintaining a predetermined interval so that the rack bushing 180 does not collide with the rack housing 160 when the rack 130 moves in the axial direction, in order to prevent rattling noises between the rack bushing 180 and the rack housing 160.

[0232] In a Fig. In the illustrated embodiment 16, the anti-rotation element 150 can support the outer circumferential surface of the rack 130 to prevent the rack 130 from rotating about the central axis, and the anti-rotation element 150 can be supported by the inner circumferential surface of the rack housing 160.

[0233] The anti-rotation element 150 can include a rack bushing 170 having a first support section 171 and a second support section 175. The first support section 171 can be configured to support the support surface 130-1 formed on the outer circumferential surface of the rack 130. The second support section 175 can extend from or be connected to the first support section 171, can be configured to support the outer circumferential surface of the rack 130, and can have an outer circumferential surface on which a locking projection 173, coupled to the housing groove 162, is formed on the inner circumferential surface of the rack housing 160.

[0234] For example, the support surface 130-1, which is formed on a part of the outer circumferential surface of the rack 130, can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0235] The support surface 130-1 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0236] The support surface 130-1 extends longitudinally in the axial direction of the rack 130 in order to be supported by the first support section 171 when the rack 130 moves in the axial direction.

[0237] An inner circumferential surface 171a of the first support section 171 can be in close contact with and supported by the support surface 130-1 of the rack 130, and an outer circumferential surface of the first support section 171 can be spaced away from the inner circumferential surface of the rack housing 160.

[0238] A coating layer can be provided on the support surface 130-1 and the outer circumferential surface of the rack 130 and can be made of a low-friction material, such as fluoropolymer or ceramic, to minimize or reduce friction with the rack bushing 170.

[0239] The second support section 175 extends from the first support section 171 in the circumferential direction or is connected to it and surrounds the outer circumferential surface of the rack 130.

[0240] The fixing projection 173 extends radially from the outer circumferential surface of the second support section 175.

[0241] The housing groove 162 can be formed on the inner circumferential surface of the rack housing 160, and the fixing projection 173 of the second support section 175 can be inserted into or coupled to the housing groove 162, thereby preventing the rack bushing 170 from rotating.

[0242] For example, the housing groove 162 can be formed by machining or grinding the inner circumferential surface of the rack housing 160.

[0243] The housing groove 162 can be recessed from the inner circumferential surface of the rack housing 160 and can have a curved surface or a flat surface.

[0244] The rack bushing 170 can have a predetermined stiffness and elasticity and can be made from one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0245] In a Fig. In the illustrated embodiment 17, the anti-rotation element 150 can be supported by a guide cover 155 which is coupled to the rack housing 160, and can support the outer circumferential surface of the rack 130 to prevent the rack 130 from rotating about the central axis.

[0246] The anti-rotation element 150 can include a support element 151 coupled to the outer circumferential surface of the rack 130, wherein the guide cover 155 is coupled to the rack housing 160 and has an inner circumferential surface that supports the support element 151, and a fastening element 159 configured to fasten the guide cover 155 to the rack housing 160.

[0247] The support element 151 can be coupled to the outer circumferential surface of the rack 130. For example, the support element 151 can be coupled to a coupling groove 134 formed on the outer circumferential surface of the rack 130 by press fitting, bonding, or the like. The coupling groove 134 can be formed by machining or grinding the outer circumferential surface of the rack 130.

[0248] The coupling groove 134 can be recessed into the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0249] The rack housing 160 can have an opening at a position facing or corresponding to the support element 151, and the guide cover 155 is coupled to and covers the opening of the rack housing 160.

[0250] The inner circumferential surface of the guide cover 155 can have a support groove 155-1 into which and through which the support element 151 is inserted and supported.

[0251] The support groove 155-1 of the guide cover 155 extends longitudinally in the axial direction of the rack 130, so that the support element 151 can be supported by the support groove 155-1 when the rack 130 moves in the axial direction.

[0252] The support groove 155-1 can, for example, without being limited to, have a trapezoidal shape with a width that increases in the direction of the support element 151.

[0253] The support element 151 can have a trapezoidal shape with a width that decreases from the outer circumferential surface of the rack 130 in the direction of the support groove 155-1.

[0254] Two opposing side surfaces of the support groove 155-1 can be in close contact with and supported by the support element 151, and an inner upper surface of the support groove 155-1, which is positioned between the two opposing side surfaces of the support groove 155-1, can be spaced away from one end of the support element 151.

[0255] A coating layer can be provided on the support groove 155-1 or the support element 151 and can be made of a low-friction material, such as fluoropolymer or ceramic, to reduce or minimize friction.

[0256] The support groove 155-1 may contain grease to minimize friction with the support element 151.

[0257] The guide cover 155 can be attached to the rack housing 160 by means of the fastening element 159.

[0258] Furthermore, an elastic element 157 can be arranged between the guide cover 155 and the rack housing 160, which is penetrated by the fastening element 159 and is configured to elastically support the guide cover 155 and the rack housing 160.

[0259] A sealing element or seal 158 can be applied to the ends of the guide cover 155 and the outer circumferential surface of the rack housing 160 to prevent moisture or dust from being introduced from the outside of the rack housing 160.

[0260] The support element 151 and the guide cover 155 can have a predetermined stiffness and elasticity and can be made of one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0261] In a Fig. In the illustrated embodiment 18, the anti-rotation element 150 can be supported by a housing cover 154, which is coupled to the rack housing 160, and the outer circumferential surface of the rack 130, thereby preventing the rack 130 from rotating about the central axis of the rack 130.

[0262] The anti-rotation element 150 can include the support element 151, which supports the outer circumferential surface of the rack 130, wherein the housing cover 154 is attached to the rack housing 160 and has the inner circumferential surface to which the support element 151 is coupled, and the fastening element 159, which is configured to fasten the housing cover 154 to the rack housing 160.

[0263] A rack support groove 134, through which the support element 151 is supported, is formed on the outer circumferential surface of the rack 130.

[0264] The rack support groove 134 extends longitudinally in the axial direction of the rack 130, so that the support element 151 can be supported by the rack support groove 134 when the rack 130 moves in the axial direction.

[0265] The rack support groove 134 can be recessed from the outer circumferential surface of the rack 130 and can have a curved surface or a flat surface.

[0266] The rack housing 160 can have an opening at a position corresponding to or facing the rack support groove 134, and the housing cover 154 is coupled to the opening of the rack housing 160.

[0267] A cover support groove 156, in which the support element 151 is positioned, can be formed on the inner circumferential surface of the housing cover 154.

[0268] The rack support groove 134 can, for example, but is not limited to, have a trapezoidal shape with a width that increases towards the housing cover 154.

[0269] The support element 151 can have a trapezoidal shape with a width that decreases from the cover support groove 156 towards the rack support groove 134.

[0270] Two opposing side surfaces of the rack support groove 134 can be in close contact with and supported by the support element 151, and an inner surface of the rack support groove 134, which is positioned between the two opposing side surfaces of the rack support groove 134, can be spaced away from the end of the support element 151.

[0271] A coating layer can be provided on the rack support groove 134 or the support element 151 and can be made of a low-friction material, such as fluoropolymer or ceramic, to reduce or minimize friction.

[0272] The rack support groove 134 can be greased or filled to reduce or minimize friction with the support element 151.

[0273] The housing cover 154 can be attached to the rack housing 160 by means of the fastening element 159.

[0274] The seal or sealing element 158 ​​can be applied to the end section of the housing cover 154 and the outer circumferential surface of the rack housing 160 to prevent moisture or dust from being introduced from the outside of the rack housing 160.

[0275] The support element 151 and the housing cover 154 can have a predetermined stiffness and elasticity and can be made of one or more materials selected from a group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and phenolformaldehyde (PF).

[0276] As described above, a steer-by-wire steering device according to some embodiments of the present disclosure can include a plurality of motors and provide a steering force for a rack. Additionally, a steer-by-wire steering device according to some embodiments of the present disclosure can prevent unnecessary rotation of a rack, even though a means for preventing rack rotation is provided and the pinion is excluded.

[0277] The following describes various embodiments of a method for determining the position of a rack in a steer-by-wire steering system. Some embodiments of the rack-determining method described below can be applied independently of the motor configuration, position, and shape mentioned above. However, certain embodiments of the rack-determining method can be applied to the aforementioned motor configuration, position, and shape. Furthermore, the rack-determining method can be applied in exemplary embodiments of the steer-by-wire steering system that do not include the anti-rotation element, or it can be applied in any type of anti-rotation element.

[0278] In the steer-by-wire steering system, the electronic control unit 110 can control the operating processes of one or more drive motors (e.g., 145 and 147). For example, the electronic control unit 110 can receive information or one or more signals from one or more sensors assigned to the vehicle and control one or more drive motors based on the information or signals received from one or more sensors.

[0279] One or more sensors include various sensors, such as a steering angle sensor, a steering torque sensor, a vehicle speed sensor, a rack position sensor, and any type of sensor that is attached to or provided in the vehicle in connection with the vehicle's steering system. However, as described above, according to some embodiments of the present disclosure, the pinion may not be included in the steer-by-wire steering device if the rack is configured to be moved by the first motor and the second motor. In this case, the rack position sensor, which is configured to detect an absolute position of the rack, may not be included in the steer-by-wire steering device.Alternatively, the rack position sensor, configured to detect the absolute position of the rack, can be included in a gearbox configured to connect the first and / or second motor to the rack.

[0280] First, various embodiments for identifying the absolute position (or an absolute angle) of the rack are described. Then, an embodiment is described that includes an absolute angle sensor configured to detect the absolute position (or an absolute angle) of the rack.

[0281] The electronic control unit 110 can control the operation of the steering shaft motor 120. The electronic control unit 110 can be configured as a single, physically integrated chip. Alternatively, the electronic control unit 110 can be configured using a variety of chips. For example, each of the reaction force motor, drive motor, main control unit, and any component of the steer-by-wire steering system includes one or more chips to perform its necessary operations.

[0282] In addition, the electronic control unit 110 can control the direction of travel of the vehicle according to the driver's steering intention by controlling the operating processes of the multitude of drive motors (e.g. 145 and 147).

[0283] Multiple electronic control units 110 can be provided in the steer-by-wire steering system to ensure redundancy and to perform the same operation consistently or stably, even if any one of the multiple electronic control units 110 is abnormal or inoperative. Alternatively, the multiple electronic control units 110 include a master electronic control unit and a sub-electronic control unit. The master electronic control unit can control the operation of the steer-by-wire steering system when the master electronic control unit is in a normal state, and the sub-electronic control unit can control the operation of the steer-by-wire steering system when the master electronic control unit is abnormal or inoperative.

[0284] The electronic control unit 110 can control the vehicle's steering in response to various pieces of information. The steer-by-wire (SBW) system may require precise information regarding the position of the rack and pinion to accurately control the vehicle's steering, especially when multiple motors are used to drive the rack.

[0285] For this purpose, the electronic control unit 110 can receive the rack position information from the rack position sensor. Alternatively, the electronic control unit 110 can estimate the rack position using the positions of the multiple motors without the rack position sensor.

[0286] For example, the electronic control unit 110 can receive rotation information from each of the motors from the plurality of motor position sensors. In an exemplary embodiment of the present disclosure, the motor rotation information can include rotation information from the first motor and rotation information from the second motor. The rotation information of the first motor can be received from a first motor position sensor that is contained in or associated with the first motor. The rotation information of the second motor can be received from a second motor position sensor that is contained in or associated with the second motor.

[0287] The motor position sensor can detect rotational information from each of the motors. It can detect the rotation of a motor shaft. Alternatively, it can detect the rotation of any rotatable component or structure connected to or associated with the motor shaft. The sensor can detect a rotational position between 0 and 360 degrees relative to the motor's rotation. For example, it can measure the angle of rotation and / or the position of the motor.

[0288] For example, the motor position sensor can be an optical sensor or encoder configured to detect a position by emitting light onto a rotating plate or disk. Alternatively, the motor position sensor can be a magnetic sensor or encoder configured to measure the position of a rotor by detecting a magnetic field. Alternatively, the motor position sensor can be an incremental sensor or encoder configured to measure a change in the relative position of a rotor by outputting a predetermined pulse. Alternatively, the motor position sensor can be an absolute sensor or encoder configured to measure the absolute position of a rotor by outputting a unique value with respect to a given position. The motor position sensor according to certain embodiments of this disclosure can provide a precise position and / or speed of the motor.

[0289] For example, a Hall sensor that measures the position of a motor by detecting a change in the magnetic flux of a rotor to which a permanent magnet or magnetic material is attached or mounted can be used as the motor position sensor. The motor of the steer-by-wire steering device can be a brushless direct current (BLDC) motor, and three Hall sensors with a phase difference of 120 degrees or 60 degrees can be arranged or configured to detect the position of the motor. Additionally, the motor position sensor can be a resolver configured to measure a position analogously by using a change in voltage, or an inductive position sensor configured to detect a position using an electromagnetic induction principle. In the present disclosure, any type of sensor can be used as the motor position sensor.

[0290] The motor position sensor can measure an absolute position or an absolute angle value based on a specific position of the motor. Alternatively, the motor position sensor can detect a relative position with respect to a reference position. Alternatively, the motor position sensor can measure the electrical position of a rotor in a BLDC or permanent magnet synchronous motor (PMSM).

[0291] A rotation angle in a single revolution is an angle between 0 and 360 degrees, and therefore a rotation angle can only be represented in a single revolution. Consequently, the absolute position of the motor, which lies beyond 360 degrees, cannot be identified because the angle of the motor's rotor resets after a complete revolution. However, there is an absolute motor position sensor that can measure the motor's position over multiple revolutions, but it has a complex configuration and structure and is more expensive.

[0292] Without using an absolute motor position sensor, some embodiments of the present disclosure can detect an absolute position of the rack using at least two motor position sensors that measure a relative position.

[0293] For example, if two motors are moving the same rack and have different rotational speeds, the angles of rotation measured by the two motor position sensors of the two motors can range from 0 degrees to 360 degrees. If the motor position sensor is not an absolute angle sensor, the angle measured by the motor position sensor is not recorded or stored, and the angle of rotation detected by the motor position sensor of the first motor can be between 0 degrees and 360 degrees, and the angle of rotation detected by the motor position sensor of the second motor can also be between 0 degrees and 360 degrees.

[0294] The electronic control unit 110 can receive the rotation angle detected by the motor position sensor of the first motor and the rotation angle detected by the motor position sensor of the second motor. The electronic control unit 110 estimates the absolute position of the rack using the two rotation angles (i.e., motor positions) detected by each of the two motor position sensors of the two motors.

[0295] As described above, in certain embodiments of the present disclosure, the first motor and the second motor are operatively connected to a single ball nut, which is operatively coupled to the rack, and move the rack at different rotational speeds. Although the first motor and the second motor rotate at different speeds, they must therefore rotate the ball nut at the same speed. Therefore, the motor pulley of the first motor and the motor pulley of the second motor can be configured with different gear ratios.

[0296] The transmission ratio can refer, for example, but is not limited to, a ratio of the number of threads or diameters of pulleys. For instance, the transmission ratio can be the ratio between the number of threads or diameter of a motor pulley connected to a motor shaft of the first motor and the number of threads or diameter of a motor pulley connected to a motor shaft of the second motor. There can be a significant difference in the transmission ratio if the diameters of the motor pulleys are different.

[0297] The first motor and the second motor can rotate at different speeds, and the electronic control unit 110 can receive different motor rotation information from the motor position sensors of the first and second motors.

[0298] The electronic control unit 110 can determine the absolute position of the rack using preset information and motor rotation information from the first and second motors.

[0299] For example, the difference in rotational speed between the two motors can vary depending on the absolute position of the rack.

[0300] For example, the electronic control unit 110 can determine the absolute position of the rack by monitoring a change in the rotation information of the two motors. For example, the electronic control unit 110 can determine the position of the rack using equation 1. R=K360×θ+K×n

[0301] R represents a linear position of the rack, θ represents a phase difference between the first rotation information of the first motor and the second rotation information of the second motor, K represents a distance by which the rack is moved while a phase difference between the first rotation information and the second rotation information changes from 0 and becomes 0 the next time the phase difference moves in one direction, and n represents the number of times the phase difference becomes 0 while the rack moves in one direction.

[0302] This means that the electronic control unit 110 can cumulatively identify the position of the rack by consistently monitoring the phase difference between the first rotation information of the first motor and the second rotation information of the second motor and recording the number of times the phase difference becomes 0.

[0303] In another example, the electronic control unit 110 can determine the position of the rack based on a preset reference value. The movable range of the rack is structurally limited. Therefore, the multitude of rack positions corresponding to the first rotation information from the first motor and the second rotation information from the second motor can be calculated in advance and stored in the memory of the electronic control unit 110 in the form of a table or other data formats.

[0304] When the first rotation information from the first motor and the second rotation information from the second motor are received, the electronic control unit 110 can estimate the absolute position of the rack by comparing the first and second rotation information from the first and second motors with pre-stored data. However, in this case, the first and second rotation information must be designed to have different values ​​within a linearly movable range of the rack. Therefore, a difference in the gear ratio between the first and second motors must be set so that the first and second rotation information from the first and second motors do not overlap or correspond to two or more absolute positions of the rack.

[0305] For example, the electronic control unit 110 can estimate the absolute position of the rack using equation 2. A={(first rotation information+m)×first translation ratio} B={(second rotation information+m)×second translation ratio} Rack position R = intersection of A and B.

[0306] Here, m is a natural number equal to or greater than 1 and equal to or less than a maximum movement distance of the rack.

[0307] Fig. Figure 19 is a diagram illustrating a method for estimating the position of a rack using a difference between first rotation information from a first motor and second rotation information from a second motor. Fig. Figure 19 illustrates a relationship between the first rotation information of the first motor and the second rotation information of the second motor and a linear position of a rack within a movable range of 0 to 75 mm (or + / - 85 mm). As described above, the first and second gear ratios can be adjusted so that the first rotation information of the first motor and the second rotation information of the second motor do not overlap or correspond to multiple positions of the rack.

[0308] Referring now to Fig. Figure 20 illustrates a steer-by-wire system 10 for use in a vehicle 1 according to an exemplary embodiment. In a conventional automotive steering system, such as an electric power steering system (EPS system), a steering wheel is mechanically coupled to one or more road wheels (e.g., front road wheels). However, the steer-by-wire system 10 according to an embodiment of the present disclosure removes this mechanical connection and instead electronically controls a steering angle of road wheels 30 based on a measurement from a steering wheel or handwheel 20 and / or one or more control signals from a controller 50, and provides feedback to a driver or operator of the vehicle 1 using a plurality of actuators, such as electric motors.Furthermore, in the steer-by-wire system 10, the steering angle of road wheels 30 can be controlled by one or more control signals generated by an autonomous driving system or an advanced driver assistance system (ADAS) and / or by the controller 50 based on data from one or more sensors.

[0309] The steer-by-wire system 10 enables the driver or operator of the vehicle 1 to control the direction of the vehicle 1 or the road wheels 30 of the vehicle 1 by operating the steering wheel 20. The steering wheel 20 is operationally or mechanically coupled to or fixed to a steering shaft (or steering column) 22. The steering wheel 20 can be connected directly or indirectly to the steering shaft 22. For example, the steering wheel 20 can be connected to the steering shaft 22 by a gear, a shaft, a belt, and / or any connecting element. Alternatively, the steering wheel 20 can be fixed to the steering shaft 22. The steering shaft 22 can rotate together with the steering wheel 20.

[0310] One or more steering wheel sensors 40 can be configured to detect a position, angular displacement, or travel 25 of the steering shaft 22 or the steering wheel 20, as well as the torque of the angular displacement or travel 25 of the steering shaft 22 or the steering wheel 20. The steering wheel sensor 40 provides electrical signals to the controller 50 indicating the angular displacement and / or torque 25. The controller 50 sends and / or receives signals to and / or from an upper actuator 27 (e.g., a steering feedback actuator with an electric motor) to actuate the upper actuator 27 in response to the angular displacement and / or torque 25 of the steering wheel 20. The upper actuator 27 rotates or moves the steering wheel 20 to provide feedback to the driver or operator in response to the control signals received from the controller 50 (similar to the feedback provided by the wheels in a vehicle with manual steering).

[0311] In the steer-by-wire system 10, the steering wheel 20 can be mechanically isolated from the road wheels 30. Accordingly, the steer-by-wire steering system 10 must provide the driver or operator with the same "road feel" that the driver receives with a direct mechanical connection. Furthermore, it is desirable to have a device that provides a mechanical "road feel" in the event of multiple electronic faults in the steer-by-wire system. Additionally, a device that provides a positive centered feel and precise torque variation when the steering wheel is turned is also desirable. Therefore, the vehicle 1 can include the upper actuator 27 (e.g., the steering feedback actuator).

[0312] The upper actuator 27 can, for example, but is not limited to, comprise an electric motor connected to the steering shaft or steering column 22. For example, a gear or belt assembly can connect an output of the upper actuator 27 to the steering shaft 22. Alternatively, the upper actuator 27 can be directly coupled to the steering shaft 22 or the handwheel 20. The upper actuator 27 is actuated to provide resistance to the rotation of the steering wheel 20. The controller 50 is electrically coupled to the sensors 40 and the upper actuator 27. The controller 50 receives signals from the sensors 40 indicating the applied torque and the angular rotation 25 of the steering wheel 20.In response to the signals from the sensors 40, the controller 50 generates and transmits a signal corresponding to the detected torque and angular rotation of the steering wheel 20 as detected by the sensors 40, and the upper actuator 27 generates a resistance torque against the rotation of the steering wheel 20 in response to the signal from the controller 50 to provide the driver with the steering feel.

[0313] The controller 50 also transmits signals or commands to a lower actuator 32 (e.g., a road wheel actuator). The lower actuator 32 controls the linear movement of a rack 36 in response to the control signals received from the controller 50. For example, the lower actuator 32 generates a rotary movement in response to the control signals from the controller 50, and the rotary movement of the lower actuator 32 is converted into a linear movement of the rack 36. Tie rods and steering knuckles 37 connect the rack 36 to road or vehicle wheels 30 and convert the linear movement of the rack 36 into a rotation of the road wheels 30.

[0314] In use, the steering wheel 20 is moved angularly 25, causing the steering shaft 22 to also move angularly. The sensor 40 detects the angular displacement and the torque 25 of the steering shaft 22, which is coupled to the steering wheel 20, and the sensor 40 sends signals to the controller 50 indicating the relative amount of the angular displacement and the torque 25 of the steering shaft 22. The controller 50 sends control signals to the lower actuator 32 indicating the relative amount of the angular displacement and / or the torque of the steering shaft 22. In response, the lower actuator 32 moves the rack 36, causing the road wheels 30 to rotate. Thus, the controller 50 controls the distance by which the rack 36 is moved, based on the amount of the angular displacement 25 of the steering wheel 20. The movement of the rack 36 actuates the tie rods and steering knuckles 37 to reposition the road wheels 30 of the vehicle 1.Accordingly, when the steering wheel is turned 20 times, the road wheels are controlled 30 times to be turned.

[0315] To perform the prescribed functions and the desired processing and calculations (e.g., the identification of motor parameters, control algorithm(s), and the like), the controller 50 may, but is not limited to, include a processor (processors), a computer (computers), a DSP (digital signal processor), a memory, a register (registers), a timing controller, an interrupt (interrupts), a communication interface (communication interfaces), and input / output signal interfaces, and the like, as well as combinations comprising at least one of the foregoing. For example, the controller 50 may include input signal processing and filtering to enable accurate sampling and conversion or acquisition of such signals from communication interfaces. Although Fig. If, for example, the controller 50 is illustrated as a single controller, a person skilled in the art would understand that the controller 50 can be distributed among a multitude of vehicle controllers, such as a first circuit 320 of a first drive unit (also called powerpack) 300 and a second circuit 420 of a second drive unit 400.

[0316] Fig. Figure 21 is a perspective view showing a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 22 is a cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 23 is a partial cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 22 is a cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 23 is a partial cross-sectional view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. 24- Fig. Figure 25 is a perspective partial view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. 26- Fig. Figure 27 are partial cross-sectional views to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 28 is a partial top view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure. Fig. Figure 29 is a perspective partial view to illustrate a steer-by-wire system according to an exemplary embodiment of the present disclosure.

[0317] The lower actuator 32 (e.g. a road wheel actuator) can comprise a first drive unit 300 and a second drive unit 400.

[0318] The first drive unit 300 can comprise a first motor 310 with a first motor shaft 311, a first circuit 320, and a first sealed bearing 330. The second drive unit 400 can comprise a second motor 410 with a second motor shaft 411, a second circuit 420, and a second sealed bearing 430.

[0319] The first and second circuits 320 and 420 can comprise any suitable circuit and electronic components, such as a microprocessor, a processor, a computer, and / or memory. The first and second circuits 320 and 420 can be configured to control the first and second motors 310 and 320, for example, but not limited to, supplying power to the first and second motors 310 and 320, enabling or disabling their operation, and varying the speed and / or direction of rotation of the first and second motors 310 and 320.

[0320] The first or second sealed bearing 330 or 430 supports the first or second motor shaft 311 or 411, so that the first or second motor shaft 311 or 411 can be rotatably supported by the first or second sealed bearing 330 or 430 to rotate smoothly. The first or second sealed bearing 330 or 430 may have one or more sealing shields or protective barriers attached to the sides of the bearing to protect against external contamination, such as dirt, sand, and water.For example, the first or second sealed bearing 330 or 430 can be arranged around the hole in the first or second drive unit housing 350 or 450 through which the first or second motor shaft 311 or 411 passes. Therefore, the first or second sealed bearing 330 or 430 can prevent external contaminants, such as dust, moisture, and dirt, from entering the first or second drive unit housing 350 or 450. The first or second sealed bearing 330 or 430 can also prevent external contaminants from entering the first or second drive unit 300 or 400 from within a gear cavity. Because the first or second sealed bearing 330 or 430 has integral seals, less space can be required in the first or second drive unit 300 or 400, and production efficiency can be improved.

[0321] A first drive pulley 360 can be provided on the first motor shaft 311. For example, the first drive pulley 360 can be formed directly on the first motor shaft 311 or attached to the first motor shaft 311. The first drive pulley 360 can have an outer surface that engages with an inner surface of a first drive belt 370. The first drive pulley 360 of the first drive assembly 300 is rotatably connected to a rotary-to-linear conversion mechanism 500 via the first drive belt 370. For example, the first drive belt 370 connects the first drive pulley 360 of the first drive assembly 300 to a driven pulley 520 of the rotary-to-linear conversion mechanism 500. The first motor 310 can provide torque to the first drive pulley 360 via the first motor shaft 311.The torque of the first drive pulley 360 is transmitted to the first drive belt 370. When the torque is applied to the first drive belt 370, the torque of the first motor 310 of the first drive unit 300 is transmitted to the rotary-to-linear conversion mechanism 500.

[0322] A second drive pulley 460 can be provided on the second motor shaft 411. For example, the second drive pulley 460 can be formed directly on the second motor shaft 411 or attached to the second motor shaft 411. The second drive pulley 460 can have an outer surface that engages with an inner surface of a second drive belt 470. The second drive pulley 460 of the second drive assembly 400 is rotatably connected to the rotary-to-linear conversion mechanism 500 via the second drive belt 470. For example, the second drive belt 470 operatively connects the second drive pulley 460 of the second drive assembly 400 to the driven pulley 520 of the rotary-to-linear conversion mechanism 500. The second motor 410 can supply torque to the second drive pulley 460 via the second motor shaft 411.The torque of the second drive pulley 460 is transmitted to the second drive belt 470. When the torque is applied to the second drive belt 470, the torque of the second motor 410 of the second drive unit 400 is transmitted to the rotary-to-linear conversion mechanism 500.

[0323] The rotary-to-linear conversion mechanism 500 (such as a nut-and-bolt mechanism and a ball-and-nut-and-bolt mechanism) can be configured to convert a rotary motion transmitted from the first motor 300 and / or the second motor 400 via the first drive belt 310 and / or the second drive belt 410 into a linear motion to move the rack 36 linearly. The rotary-to-linear conversion mechanism 500 can include a rotatable cylinder part 510.

[0324] The rotatable cylinder part 510 can include a nut or a ball nut. At least a portion of the rack 36 is held within or surrounded by the rotatable cylinder part 510. The rotatable cylinder part 510 has a groove 521 with an internal thread on its inner surface, and at least a portion of the rack 36 has a groove 615 with an external thread for a rotatable assembly of rotatable bodies 522 (e.g., balls). The rotatable bodies 522 are arranged between the internally threaded groove 521 of the rotatable cylinder part 510 and the externally threaded groove 615 of the rack 36. The rotatable bodies 522 can be metal balls that reduce friction and transfer loads between adjacent components. The rotatable cylinder part 510 is rotatably supported by the rack 36 via the rotatable bodies 522 and a bearing 540.In alternative embodiments of the present disclosure, however, the groove 521 with internal thread of the rotatable cylinder part 510 and the groove 615 with external thread of the rack 36 can engage directly with each other without the rotatable bodies 522. The driven pulley 520 can be formed directly on the rotatable cylinder 510 or attached to the rotatable cylinder 510.

[0325] The bearing 540 can support the rotatable cylindrical part 510 of the rotary-to-linear conversion mechanism 500, thus enabling the bearing 540 to support the rotary motion of the rotatable cylindrical part 510. For example, the bearing 540 can be, but is not limited to, a four-point bearing. The bearing 540 can be positioned between the rotary-to-linear conversion mechanism 500 and a non-rotating structure, for example, but is not limited to, a first housing part 380 or a second housing part 480. The bearing 540 is used to rotatably support the rotatable cylindrical part 510 for rotation relative to the non-rotating structure.

[0326] An inner race 541 of the bearing 540 can be integrated with the rotatable cylinder part 510 as a single piece, such that the inner race 541 of the bearing 540 and the nut or ball nut of the rotary-to-linear conversion mechanism 500 are integrated to form a single cylinder part, thus providing a simpler assembly process and reducing manufacturing costs. For example, the inner race 541 of the bearing 540 can be formed integrally on the outer surface of the rotatable cylinder part 510. Alternatively, the inner race 541 can be attached to the outer surface of the rotatable cylinder part 510 as a separate piece from the rotatable cylinder part 510.

[0327] The bearing 540 can comprise an outer race (or outer ring) 542. The outer race 542 can be arranged concentrically around the inner race 541 with the rolling bodies 543 between them in a plane that is generally perpendicular to a rotatable axis of the rotatable cylinder part 510 or the inner race 541 or a displaceable axis of the rack 36. The inner race 541 is rotatable, but the outer race 542 is essentially non-rotatable.

[0328] A rack housing 560 accommodates at least one section of the rack 36, the rotatable cylinder part 510, and the bearing 540. The rack housing 560 has a groove 561 recessed into its inner surface. The outer race or outer ring 542 of the bearing 540 has a flange 544 projecting radially from its outer surface. The flange 544 of the outer race 542 has a larger outer diameter than the other part of the outer race 542. The flange 544 of the outer race 542 of the bearing 540 is positioned in the groove 561 of the rack housing 560, thus securing the outer race 542 of the bearing 540 within the rack housing 560.By providing the flange part 544 of the outer race or outer ring 542 of the bearing 540, the bearing 540 can be securely held in the rack housing 560 without an additional retaining device for the bearing 540, such as a retaining ring.

[0329] The rack housing 560 can consist of several parts. For example, the rack housing 560 comprises the first housing part 380 and the second housing part 480. A first groove section 381 of the groove 561 can be formed on an end section of the first housing part 380, and a second groove section 481 of the groove 561 can be formed on an end section of the second housing part 480, such that the first groove section 381 of the first housing part 380 and the second groove section 481 of the second housing part 480 can form the groove 561 into which the flange part 544 of the outer race 542 of the bearing 540 is inserted. This configuration simplifies the process of assembling the bearing 540 and a first support 545 into the rack housing 560. One or more fastening elements 563, such as a bolt, can fasten the first housing part 380 and the second housing part 480 together.

[0330] At least part of the first support 545 can be arranged together with the flange part 544 of the outer race or outer ring 542 of the bearing 540 in the groove 561 of the rack housing 560. The first support 545 can elastically support the flange part 544 of the outer race or outer ring 542 of the bearing 540. As shown in Fig. 23 and Fig. As illustrated in Figure 24, the first support 545 is arranged on one side of the flange part 544 facing the driven pulley 520. Alternatively, the first support 545 or an additional support can be arranged on the other side 548 of the flange part 544.

[0331] While the first support 545 is arranged on one side of the outer race or outer ring 542 of the bearing 540, where the flange part 544 is formed, a second support 546 can be arranged on the opposite side of the outer race or outer ring 542 of the bearing 540, so that the second support 546 can elastically support the opposite side of the outer race or outer ring 542.

[0332] The first and second supports 545 and 546 can prevent rattling and clattering that may be caused by the movement of the outer race or outer ring 542 of the bearing 540. The rack housing 560 can incorporate one or both of the first support 545 and the second support 546.

[0333] A third support 513 can support one side of the driven pulley 520 and be arranged in a groove 514 which is recessed by an outer surface of the rotatable cylinder part 510.

[0334] The first, second, and third supports 545, 546, and 513 may be made of elastic material and have a ring shape, such as a corrugated ring. For example, the first, second, and third supports 545, 546, and 513 may be a rubber ring, a spring, or a circular metal component with a corrugated or wavy shape (e.g., a corrugated spring or a corrugated washer). However, any material or shape may be used, provided that the first, second, and third supports 545, 546, and 513 can adequately support the flange part 544 or any other part of the outer race or outer ring 542 or the driven pulley 520.

[0335] The first drive belt 370, which is operationally coupled to the first motor 310 of the first drive unit 300, is rotatably coupled to one section of the driven pulley 520, and the second drive belt 470, which is operationally coupled to the second motor 410 of the second drive unit 400, is rotatably coupled to the other section of the driven pulley 520. The outer diameter of the one section of the driven pulley 520 to which the first drive belt 370 is coupled and the outer diameter of the other section of the driven pulley 520 to which the second drive belt 470 is coupled can be the same.However, the outer diameter of one section of the driven pulley 520, to which the first drive belt 370 is coupled, may differ from the outer diameter of the other section of the driven pulley 520, to which the second drive belt 470 is coupled, if necessary to identify the linear position of the rack 36 using the Vernier algorithm. Furthermore, the number of teeth of a section of the driven pulley 520, which is provided on the rotatable part 510 of the rotary-to-linear conversion mechanism 500 and is operationally coupled to the first motor 310 of the first drive unit 300, and the number of teeth of another section of the driven pulley 520, which is provided on the rotatable part 510 of the rotary-to-linear conversion mechanism 500 and is operationally coupled to the second motor 410 of the second drive unit 400, are identical.The number of teeth of a section of the driven pulley 520, which is provided on the rotatable part 510 of the rotary-to-linear conversion mechanism 500 and is operationally coupled to the first motor 310 of the first drive unit 300, may, however, differ from the number of teeth of another section of the driven pulley 520, which is provided on the rotatable part 510 of the rotary-to-linear conversion mechanism 500 and is operationally coupled to the second motor 410 of the second drive unit 400, if necessary to identify the linear position of the rack 36 using the Vernier algorithm.

[0336] A flange projecting from the outer surface of the driven pulley 520 of the rotary-to-linear conversion mechanism 500 can be arranged between the first drive belt 370 and the second drive belt 470, such that the first drive belt 370 and the second drive belt 470 are positioned spaced apart from each other to hold the first drive belt 370 and the second drive belt 470 in place and prevent them from interfering with each other.

[0337] Both the first drive pulley 360 of the first drive unit 300 and the second drive pulley 460 of the second drive unit 400 are rotatably connected to a driven pulley 520 of the rotary-to-linear conversion mechanism 500 via the first drive belt 370 and the second drive belt 470, respectively. The configuration of the belts 370 and 470 allows an inner engagement surface of the belts 370 and 470 to engage with and encircle both the first and second drive pulleys 360 and 460 of the first and second drive units 300 and 400, and the driven pulley 520, which is attached to the rotatable part 510 of the rotary-to-linear conversion mechanism 500.The rotary motion of at least one of the first drive pulley 360 of the first drive assembly 300 and the second drive pulley 460 of the second drive assembly 400 causes a rotation of the driven pulley 520 and the rotatable part 510 of the rotary-to-linear conversion mechanism 500, and then the rotary motion of the rotatable part 510 of the rotary-to-linear conversion mechanism 500 is converted by the rotary-to-linear conversion mechanism 500 into the linear motion of the rack 36.

[0338] A first motor position sensor 390 responds to the rotation of the first motor shaft 311. The first motor position sensor 390 can be arranged in a sensing relationship with the first motor shaft 311. For example, the first motor position sensor 390 can be positioned adjacent to or around one end of the first motor shaft 311. The first motor position sensor 390 can detect or sensing an angular position of the first motor 310 (such as an angular position of a first drive gear 710 or an angular position of the first motor shaft 311) within a single rotation range that is a range from zero to three hundred and sixty degrees (0-360°). The first motor position sensor 390 can generate output signals indicating the detected angular positions of the first motor shaft 311. The first motor position sensor 390 is mounted on the first circuit board 320 and electrically connected to it.

[0339] A second motor position sensor 490 responds to the rotation of the second motor shaft 411. The second motor position sensor 490 can be arranged in a sensing relationship with the second motor shaft 411. For example, the second motor position sensor 490 can be positioned adjacent to or around one end of the second motor shaft 411. The second motor position sensor 490 can detect or sensing an angular position of the second motor 410 (such as an angular position of a second drive gear 810 or an angular position of the second motor shaft 411) within a single rotation range of zero to three hundred and sixty degrees (0-360°). The second motor position sensor 490 can generate output signals indicating the detected angular positions of the second motor shaft 411. The second motor position sensor 490 is mounted on the second circuit board 420 and electrically connected to it.

[0340] The first motor position sensor 390 can be any suitable device (or devices) for generating a signal in response to the rotation of the first motor shaft 311. For example, the first motor position sensor 390 can be an inductive sensor, a magnetic sensor (e.g., a Hall effect sensor), a magnetic resonance sensor (MR sensor), or any other sensor known in the art with similar capabilities.

[0341] In one embodiment, the first motor position sensor 390 can be a magnetic sensor (e.g., a Hall-effect sensor). The first motor shaft 311 can comprise a magnetic material such as a permanent magnet. For example, a first magnet 715 can be attached to one end of the first motor shaft 311. The first motor shaft 311 has a first shaft cover 711 that covers one end of the first motor shaft 311, and the first magnet 715 can be arranged within an interior of the first shaft cover 711 or coupled to the first shaft cover 711. In another example, a magnetic gradient is formed on a surface of the first motor shaft 311 and is defined by a plurality of alternating magnetically charged north and south elements spaced circumferentially around the circumference of the first motor shaft 311.The magnetic field between the magnetic material of the first motor shaft 311 and the first motor position sensor 390 can be varied as a function of the angular displacement of the first motor shaft 311. The first motor position sensor 390 can sense or detect the magnetic field around the first motor shaft 311 to identify an angular position of the first motor 311.

[0342] In another embodiment, the first motor position sensor 390 can be an inductive type sensor. The inductive type sensor can be configured to operate based on the principle of electromagnetic induction to detect or measure nearby metallic objects. An inductor develops a magnetic field when an electric current flows through it. Alternatively, a current flows through a circuit containing an inductor when the magnetic field through it changes. This effect can be used to detect metallic objects interacting with a magnetic field. For example, according to one embodiment of the present disclosure, the inductive type sensor can utilize aspects described in the publication dated 29.The US patent application filed in October 2024, serial number 18 / 930,897, entitled “INDUCTIVE SENSOR SYSTEM COMPRISING INDUCTIVE TORQUE AND POSITION SENSOR ASSEMBLIES”, is hereby incorporated herein by reference in its entirety.In one embodiment of the inductive-type sensor, an excitation or transmitter coil set configured to generate an electromagnetic field across the first motor shaft 311 and a receiver coil set configured to detect the electromagnetic field around the first motor shaft 311 can be contained in or attached to the first circuit board 320. Metallic material, such as a target with a metallic pattern or one or more conductive loops configured to influence the electromagnetic field generated by the excitation or transmitter coil set, can be contained in or attached to the first motor shaft 311 instead of the first magnet 715. The inductive-type sensor can reduce the size of the first drive assembly 300 and lower the manufacturing costs of the steer-by-wire system 10.

[0343] The first motor shaft 311 has a first drive gear 710. The first drive gear 710 can be attached to the first motor shaft 311 or be formed directly on the outer surface of the first motor shaft 311 as a toothed section. For example, as shown in the Fig. 26 and Fig. As shown in Figure 27, the first drive gear 710 is formed directly on or attached to an outer surface of the first shaft cover 711. When the first motor shaft 311 rotates, the first drive gear 710 rotates together.

[0344] A first driven gear 720 can be rotatably engaged with the first drive gear 710 of the first motor shaft 311. When the first motor shaft 311 rotates, the first drive gear 710 of the first motor shaft 311 drives the first driven gear 720 to rotate. The first driven gear 720 can be rotatably mounted on the inner surface of the first drive unit housing 350.

[0345] The diameter of the first driven gear 720 or the number of gear teeth of the first driven gear 720 is larger than the diameter of the first drive gear 710 or the number of gear teeth of the first drive gear 710 in order to accurately identify the angular position of the first driven gear 720 and to make the transmission ratios assigned to the first and second driven gears 710 and 810 slightly different.

[0346] A first gear position sensor 730 responds to the rotation of the first driven gear 720. The first gear position sensor 730 can be arranged in a sensing relationship with the first driven gear 720. For example, the first gear position sensor 730 can be positioned adjacent to or around the first driven gear 720. The first gear position sensor 730 can detect or sensing an angular position of the first driven gear 720 within a single rotation range of zero to three hundred and sixty degrees (0-360°). The first gear position sensor 730 can generate output signals indicating the detected angular positions of the first driven gear 720. The first gear position sensor 730 is mounted on the first circuit board 320 and electrically connected to it.

[0347] The first gear position sensor 730 can be any suitable device (or devices) for generating a signal in response to the rotation of the first driven gear 720. For example, the first gear position sensor 730 can be an inductive sensor, a magnetic sensor (e.g., a Hall effect sensor), a magnetic resonance sensor (MR sensor), or any other sensor known in the art with similar capabilities.

[0348] In one embodiment, the first gear position sensor 730 can be a magnetic sensor (e.g., a Hall effect sensor). The first driven gear 720 can comprise a magnetic material such as a permanent magnet. For example, a third magnet 725 can be coupled to the first driven gear 720. As shown in Fig. As illustrated in Figure 27, the first driven gear 720 can have a first groove 727 formed on a surface of the first driven gear 720 facing the first gear position sensor 730, such that the third magnet 725 can be arranged in the first groove 727 of the first driven gear 720. In another example, a magnetic gradient can be formed on a surface of the first driven gear 720 and defined by a plurality of alternating magnetically charged north and south elements spaced circumferentially around the circumference of the first driven gear 720. The magnetic field between the magnetic material of the first driven gear 720 and the first gear position sensor 730 can be varied as a function of the angular displacement of the first driven gear 720.The first gear position sensor 730 can detect or sensing the magnetic field around the first driven gear 720 to identify an angular position of the first driven gear 720.

[0349] In another embodiment, the first gear position sensor 730 can be an inductive type sensor. The inductive type sensor can be configured to operate based on the principle of electromagnetic induction to detect or measure nearby metallic objects. An inductor develops a magnetic field when an electric current flows through it. Alternatively, a current flows through a circuit containing an inductor when the magnetic field through it changes. This effect can be used to detect metallic objects interacting with a magnetic field. For example, according to one embodiment of the present disclosure, the inductive type sensor can utilize aspects described in the patent application dated 29.The US patent application filed in October 2024, serial number 18 / 930,897, entitled “INDUCTIVE SENSOR SYSTEM COMPRISING INDUCTIVE TORQUE AND POSITION SENSOR ASSEMBLIES”, is hereby incorporated herein by reference in its entirety.In one embodiment of the inductive-type sensor, an excitation or transmitter coil set configured to generate an electromagnetic field across the first driven gear 720, and a receiver coil set configured to detect the electromagnetic field around the first driven gear 720, can be contained in or attached to the first circuit board 320. Metallic material, such as a target with a metallic pattern or one or more conductive loops configured to influence the electromagnetic field generated by the excitation or transmitter coil set, can be contained in or attached to the first driven gear 720 instead of the third magnet 725. The inductive-type sensor can reduce the size of the first drive assembly 300 and lower the manufacturing costs of the steer-by-wire system 10.

[0350] The second motor position sensor 490 can be any suitable device (or devices) for generating a signal in response to the rotation of the second motor shaft 411. For example, the second motor position sensor 490 can be an inductive sensor, a magnetic sensor (e.g., a Hall effect sensor), a magnetic resonance sensor (MR sensor), or any other sensor known in the art with similar capabilities.

[0351] In one embodiment, the second motor position sensor 490 can be a magnetic sensor (e.g., a Hall effect sensor). The second motor shaft 411 can comprise a magnetic material such as a permanent magnet. For example, a second magnet 815 can be attached to one end of the second motor shaft 411. The second motor shaft 411 has a second shaft cover 811 that covers one end of the second motor shaft 411, and the second magnet 815 can be arranged within an interior of the second shaft cover 811 or coupled to the second shaft cover 811. In another example, a magnetic gradient is formed on a surface of the second motor shaft 411 and is defined by a plurality of alternating magnetically charged north and south elements spaced circumferentially around the circumference of the second motor shaft 411.The magnetic field between the magnetic material of the second motor shaft 411 and the second motor position sensor 490 can be varied as a function of the angular displacement of the second motor shaft 411. The second motor position sensor 490 can sense or detect the magnetic field around the second motor shaft 411 to identify an angular position of the second motor 410.

[0352] In another embodiment, the second motor position sensor 490 can be an inductive type sensor. The inductive type sensor can be configured to operate based on the principle of electromagnetic induction to detect or measure nearby metallic objects. An inductor develops a magnetic field when an electric current flows through it. Alternatively, a current flows through a circuit containing an inductor when the magnetic field through it changes. This effect can be used to detect metallic objects interacting with a magnetic field. For example, according to one embodiment of the present disclosure, the inductive type sensor can utilize aspects described in the publication dated 29.The US patent application filed in October 2024, serial number 18 / 930,897, entitled “INDUCTIVE SENSOR SYSTEM COMPRISING INDUCTIVE TORQUE AND POSITION SENSOR ASSEMBLIES”, is hereby incorporated herein by reference in its entirety.In one embodiment of the inductive-type sensor, an excitation or transmitter coil set configured to generate an electromagnetic field across the second motor shaft 411, and a receiver coil set configured to detect the electromagnetic field around the second motor shaft 411, can be contained in or attached to the second circuit board 420. Metallic material, such as a target with a metallic pattern or one or more conductive loops configured to influence the electromagnetic field generated by the excitation or transmitter coil set, can be contained in or attached to the second motor shaft 411 instead of the second magnet 415. The inductive-type sensor can reduce the size of the second drive assembly 400 and lower the manufacturing costs of the steer-by-wire system 10.

[0353] The second motor shaft 411 has a second drive gear 810. The second drive gear 810 can be attached to the second motor shaft 411 or be formed directly on the outer surface of the second motor shaft 411 as a toothed section. For example, as shown in the Fig. 26 and Fig. As shown in Figure 27, the second drive gear 810 is formed directly on or attached to an outer surface of the second shaft cover 811. When the second motor shaft 411 rotates, the second drive gear 810 rotates together.

[0354] A second driven gear 820 can be rotatably engaged with the second drive gear 810 of the second motor shaft 411. When the second motor shaft 411 rotates, the second drive gear 810 of the second motor shaft 411 drives the second driven gear 820 to rotate. The second driven gear 820 can be rotatably mounted on the inner surface of the second drive unit housing 450.

[0355] The diameter of the second driven gear 820 or the number of gear teeth of the second driven gear 820 is larger than the diameter of the second drive gear 810 or the number of gear teeth of the second drive gear 810 in order to accurately identify the angular position of the second driven gear 820 and to make the transmission ratios assigned to the first and second driven gears 710 and 810 slightly different.

[0356] A second gear position sensor 830 responds to the rotation of the second driven gear 820. The second gear position sensor 830 can be arranged in a sensing relationship with the second driven gear 820. For example, the second gear position sensor 830 can be positioned adjacent to or around the second driven gear 820. The second gear position sensor 830 can detect or sensing an angular position of the second driven gear 820 within a single rotation range of zero to three hundred and sixty degrees (0-360°). The second gear position sensor 830 can generate output signals indicating the detected angular positions of the second driven gear 820. The second gear position sensor 830 is mounted on the second circuit board 420 and electrically connected to it.

[0357] The second gear position sensor 830 can be any suitable device (or devices) for generating a signal in response to the rotation of the second driven gear 820. For example, the second gear position sensor 830 can be an inductive sensor, a magnetic sensor (e.g., a Hall effect sensor), a magnetic resonance sensor (MR sensor), or any other sensor known in the art with similar capabilities.

[0358] In one embodiment, the second gear position sensor 830 can be a magnetic sensor (e.g., a Hall effect sensor). The second driven gear 820 can comprise a magnetic material such as a permanent magnet. For example, a fourth magnet 825 can be coupled to the second driven gear 820. As shown in Fig.As illustrated in Figure 27, the second driven gear 820 can have a second groove 827 formed on a surface of the second driven gear 820 facing the second gear position sensor 830, such that the fourth magnet 825 can be arranged in the second groove 827 of the second driven gear 820. In another example, a magnetic gradient can be formed on a surface of the second driven gear 820 and defined by a plurality of alternating magnetically charged north and south elements spaced circumferentially around the circumference of the second driven gear 820. The magnetic field between the magnetic material of the second driven gear 820 and the second gear position sensor 830 can be varied as a function of the angular displacement of the second driven gear 820.The second gear position sensor 830 can detect or sensing the magnetic field around the second driven gear 820 to identify an angular position of the second driven gear 820.

[0359] In another embodiment, the second gear position sensor 830 can be an inductive type sensor. The inductive type sensor can be configured to operate based on the principle of electromagnetic induction to detect or measure nearby metallic objects. An inductor develops a magnetic field when an electric current flows through it. Alternatively, a current flows through a circuit containing an inductor when the magnetic field through it changes. This effect can be used to detect metallic objects interacting with a magnetic field. For example, according to one embodiment of the present disclosure, the inductive type sensor can utilize aspects described in the patent application dated 29.The US patent application filed in October 2024, serial number 18 / 930,897, entitled “INDUCTIVE SENSOR SYSTEM COMPRISING INDUCTIVE TORQUE AND POSITION SENSOR ASSEMBLIES”, is hereby incorporated herein by reference in its entirety.In one embodiment of the inductive-type sensor, an excitation or transmitter coil set configured to generate an electromagnetic field across the second driven gear 820, and a receiver coil set configured to detect the electromagnetic field around the second driven gear 820, can be contained in or attached to the second circuit board 420. Metallic material, such as a target with a metallic pattern or one or more conductive loops configured to influence the electromagnetic field generated by the excitation or transmitter coil set, can be contained in or attached to the second driven gear 820 instead of the fourth magnet 825. The inductive-type sensor can reduce the size of the second drive assembly 400 and lower the manufacturing costs of the steer-by-wire system 10.

[0360] A processor, contained in at least one of the controller 50, the first circuit 320, the second circuit 420, or an electronic control unit of the vehicle 1, can receive the angular position of the first driven gear 720 and the angular position of the second driven gear 820 from the first gear position sensor 730 and the second gear position sensor 830. The processor can receive the angular position of the first driven gear 720, detected by the first gear position sensor 730, and the angular position of the second driven gear 820, detected by the second gear position sensor 830, via inter-package communication or a device control network (Controller Area Network, CAN).The processor can identify the linear position of the rack 36 based on the angular position of the first driven gear 720, detected by the first gear position sensor 730, and the angular position of the second driven gear 820, detected by the second gear position sensor 830. For example, a Vernier algorithm can be used to determine the linear position of the rack 36 based on the angular positions of the first driven gear 720 and the second driven gear 820. The gear ratio between the first driven gear 720 and the first drive gear 710 is different from the gear ratio between the second driven gear 820 and the second drive gear 810.For example, the gear ratio between the first driven gear 720 and the first drive gear 710 is 16:36, and the gear ratio between the second driven gear 820 and the second drive gear 810 is 16:37. However, if the gear ratios between the first driven gear 720 and the first drive gear 710 and the second driven gear 820 and the second drive gear 810 differ, any gear ratio can be used for the first drive gear 710, the first driven gear 720, the second drive gear 810, and the second driven gear 820, if appropriate or necessary. The Vernier algorithm can compute a value using two related variables with different phases or cycles.Due to the different transmission ratios assigned to the first driven gear 720 and the second driven gear 820, the processor can identify the linear position of the rack 36 using the phase difference of the angular position of the first driven gear 720, detected by the first gear position sensor 730, and the angular position of the second driven gear 820, detected by the second gear position sensor 830, with different cycles.By using the Vernier algorithm based on the different rotation cycles of the first driven gear 720 and the second driven gear 820, caused by a difference between a gear ratio between the first driven gear 720 and the first drive gear 710 and another gear ratio between the second driven gear 820 and the second drive gear 810, the position of the rack 36 can be determined without a learning algorithm, an electronic rotation counter or a linear position sensor to detect the linear position of the rack 36.This is possible because both the first drive unit 300 and the second drive unit 400 are kept synchronized with the movement of the rack 36 by the common driven pulley 520, which is operationally connected to both the first drive belt 370 of the first drive unit 300 and the second drive belt 470 of the second drive unit 400, and the first drive belt 370 and the second drive belt 470 are operationally connected to the first motor shaft 311 and the second motor shaft 411, which rotate the first driven gear 710 and the second driven gear 810, respectively.

[0361] In contrast to an embodiment which sets the rotational ratios assigned to the first motor 310 and the second motor 410 by means of the first drive pulley 360, the second drive pulley 460, and the driven pulley 520 to determine a linear position of the rack 36, the sizes of the first and second drive units 300 and 400 can be further reduced or minimized by using different transmission ratios assigned to the first driven gear 720 of the first drive unit 300 and the second driven gear 820 of the second drive unit 400.

[0362] One or more rack supports 550 can be configured to support the rack 36. The rack support 550 can limit the rotation of the rack 36 to prevent it from rotating relative to a non-rotating structure, for example, but not limited to, a rack housing 560. To prevent rotation of the rack 36, for example, the rack support 550 includes a pre-tensioned roller or a rotatable rack shoe, and the rack 36 has a substantially flat or slightly curved surface or shape that corresponds to a shape of the rack support 550, such that the rack 36 is displaceable while being unable to rotate relative to the rack housing 560.The cross-section of a portion of the rack 36 can be substantially D-shaped and have a flat or slightly curved surface to be operationally associated with the rack support 550. Alternatively, the rack 36 has a groove (or projection) that interlocks with a projection (or groove) of the rack support 550 to limit the rotational movement of the rack 36.

[0363] The rack support 550 can limit the linearly movable range of the rack 36. The rack support 550 can provide stop positions that limit the travel of the rack 36 (e.g., a linearly movable range of the rack 36) and thus limit the linear movement of the rack 36, preventing the rack 36 from exceeding linear movement limits.

[0364] For example, one rack support 550 can be arranged on one side of the rack housing 560 and another rack support 550 can be arranged on the other side of the rack housing 560.

[0365] The first housing part 380 has an interior space for receiving the first drive pulley 360, the first drive belt 370, and a section of the driven pulley 520 of the rotary-to-linear conversion mechanism 500. The second housing part 480 has an interior space for receiving the second drive pulley 460, the second drive belt 470, and the other section of the driven pulley 520 of the rotary-to-linear conversion mechanism 500. The first housing part 380 and the second housing part 480 can be designed as separate pieces and coupled together.

[0366] The first housing part 380 and the second housing part 480 are nested together at the central section of the rack housing 560. The first motor shaft 311 of the first motor 310 of the first drive unit 300 and the second motor shaft 411 of the second motor 410 of the second drive unit 400 can be arranged coaxially. The first drive belt 370 and the second drive belt 470 are arranged parallel to each other and coupled to a common driven pulley 520 of the rotary-to-linear conversion mechanism 500.

[0367] These configurations of the first housing part 370 and the second housing part 380 can reduce component complexity and facilitate the assembly and production of the steer-by-wire system 10.

[0368] Although the exemplary embodiments have been described in detail, it is understood that various changes, substitutions, and modifications may be made here without deviating from the fundamental idea and scope of the application as defined by the appended claims. Furthermore, the scope of the present application is not intended to be limited to the specific embodiments of the process, the machine, the manufacture, and the composition of substances, agents, methods, and steps described in the description.As a person skilled in the art will readily recognize from the disclosure, processes, machinery, manufacturing, material compositions, agents, methods, or steps that currently exist or may be developed in the future, which perform essentially the same function or achieve essentially the same result as the corresponding embodiments described herein, may be used in accordance with the embodiments and alternative embodiments. Accordingly, the attached claims, within their scope, are intended to include such processes, machinery, manufacturing, material compositions, agents, methods, or steps.

Claims

[1] Steer-by-wire system, including: a first drive unit comprising a first motor with a first motor shaft and a first gear configured to be rotated by a rotation of the first motor shaft; a second drive unit comprising a second motor with a second motor shaft and a second gear configured to be rotated by a rotation of the second motor shaft; and a rack which is operationally coupled to the first motor of the first drive unit and the second motor of the second drive unit, wherein the rack is configured to be linearly movable in response to a rotation of at least one of the first motor and the second motor. [2] Steer-by-wire system according to claim 1, further comprising a processor configured to identify a linear position of the rack based on a position of the first gear of the first drive unit and a position of the second gear of the second drive unit. [3] Steer-by-wire system according to claim 2, wherein a Vernier algorithm is used to identify the linear position of the rack based on the position of the first gear of the first drive unit and the position of the second gear of the second drive unit. [4] Steer-by-wire system according to claim 1, wherein: the first motor shaft includes a first shaft gear that is rotatably engaged with the first gear of the first drive unit, and The second motor shaft includes a second shaft gear that is rotatably engaged with the second gear of the second drive unit. [5] Steer-by-wire system according to claim 4, wherein a transmission ratio between the first shaft gear and the first gear rotatably meshing with each other and another transmission ratio between the second shaft gear and the second gear rotatably meshing with each other are different from each other. [6] Steer-by-wire system according to claim 4, wherein: a diameter or number of teeth of the first gear of the first drive unit is greater than a diameter or number of teeth of the first shaft gear, and a diameter or number of teeth of the second gear of the second drive unit is greater than a diameter or number of teeth of the second shaft gear. [7] Steer-by-wire system according to claim 1, wherein: the first drive unit includes a first gear position sensor configured to detect the position of the first gear of the first drive unit, and The second drive unit includes a second gear position sensor configured to detect the position of the second gear of the second drive unit. [8] Steer-by-wire system according to claim 1, wherein: the first gear of the first drive unit and / or the second gear of the second drive unit contain magnetic material, and the first gear position sensor and / or the second gear position sensor are configured to detect a magnetic field to identify the position of the first gear of the first drive unit or the position of the second gear of the second drive unit. [9] Steer-by-wire system according to claim 1, wherein: the first gear of the first drive unit and / or the second gear of the second drive unit contain metallic material, and The first gear position sensor and / or the second gear position sensor are inductive sensors configured to identify the position of the first gear of the first drive unit and / or the position of the second gear of the second drive unit using electromagnetic induction associated with the metallic material of the first gear and / or the second gear, respectively. [10] Steer-by-wire system according to claim 1, wherein: the first gear is rotatably mounted on an inner surface of a first drive unit housing, and the second gear is rotatably mounted on an inner surface of a first drive unit housing. [11] Steer-by-wire system according to claim 1, wherein: the first drive unit comprises a first circuit board on which a first gear position sensor is mounted, configured to detect the position of the first gear of the first drive unit, and The second drive unit includes a second circuit board on which a second gear position sensor is mounted, configured to detect the position of the second gear of the second drive unit. [12] Steer-by-wire system according to claim 1, wherein: the first gear of the first drive unit, which is configured to be rotated by a rotation of the first motor shaft, has a first groove in which a first magnet is fitted, and The second gear of the second drive unit, which is configured to be rotated by a rotation of the second motor shaft, has a second groove in which a second magnet is fitted. [13] Steer-by-wire system according to claim 4, wherein: at least one of the first motor shaft or the second motor shaft has a shaft cover that covers a section of the first motor shaft or the second motor shaft, wherein the first shaft gear or the second shaft gear is provided on an outer surface of the shaft cover. [14] Steer-by-wire system according to claim 4, wherein: at least one of the first motor shaft or the second motor shaft has a shaft cover that covers a section of the first motor shaft or the second motor shaft, wherein a magnet is attached to the shaft cover. [15] Steer-by-wire system according to claim 4, wherein the magnet is arranged in an interior of the shaft cover. [16] Steer-by-wire system according to claim 1, further comprising a rotary-to-linear conversion mechanism operationally coupled to the first motor of the first drive unit and the second motor of the second drive unit and configured to convert a rotary motion generated by at least one of the first motor of the first drive unit and the second motor of the second drive unit into a linear motion for linearly moving the rack. [17] Steer-by-wire system according to claim 16, wherein: The rotary-to-linear conversion mechanism includes a rotatable part that surrounds at least part of the rack in order to be rotatably coupled to the rack, and the rack is configured to be linearly movable in response to a rotation of the rotatable part of the rotary-to-linear conversion mechanism. [18] Steer-by-wire system according to claim 17, further comprising: a first belt that operatively connects the first motor of the first drive unit to the rotating part of the rotary-to-linear conversion mechanism; and a second belt that operationally connects the second motor of the second drive unit to the rotating part of the rotary-to-linear conversion mechanism, wherein the first belt is coupled to a section of the rotatable part of the rotary-to-linear conversion mechanism and the second belt is coupled to another section of the rotatable part of the rotary-to-linear conversion mechanism. [19] Steer-by-wire system according to claim 1, wherein the first motor shaft of the first drive unit and the second motor shaft of the second drive unit are arranged such that they are coaxial to each other. [20] Steer-by-wire system according to claim 17, further comprising one or more bearings supporting the rotatable part of the rotary-to-linear conversion mechanism surrounding at least a part of the rack.

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