Steer-by-wire system with two motor powerpacks

Abstract

A steer-by-wire system is provided. The steer-by-wire system comprises a first power pack and a second power pack, and a steering operably coupled to the first power pack and the second power pack, wherein the steering rack is configured to move linearly in response to the rotation of the motors of the first power pack and the second power pack. The first power pack further comprises a time generator circuit configured to generate motor position timing and provide it to controllers of the first power pack and the second power pack, wherein the time generator circuit is the only motor position timestamp generating component between the first power pack and the second power pack of the steer-by-wire system.

Description

Technology Field

[0001] Various embodiments of the present disclosure generally relate to a steering system for a vehicle, and more specifically to a steer-by-wire system. Background Technology

[0002] Vehicles require a steering system to control the direction of travel. Previously, mechanical steering systems were used. Such mechanical steering systems typically involve a mechanical coupling or connection between the steering wheel and the vehicle's road wheels. For example, in a conventional steering system consisting of a steering wheel, a steering column, a power-assisted rack and pinion system, and tie rods, the driver turns the steering wheel, causing the vehicle's road wheels to rotate through various mechanical components. Thus, the movement of the steering wheel causes a corresponding movement of the road wheels. The movement of these mechanical systems is often powered by the use of hydraulic assist devices or electric motors.

[0003] Mechanical steering systems are expected to be replaced or supplemented by electric-driven steering systems, generally known as "steer-by-wire" systems. These steer-by-wire systems replace, to varying degrees, the mechanical coupling between the steering wheel and the road wheels, for example, with one or more sensors, actuators, and electronic devices. The steer-by-wire system aims to eliminate the physical or mechanical connection between the steering wheel and the vehicle wheels and to change the direction of the vehicle wheels and provide feedback to the driver using electrically controlled motors. Despite the elimination of the mechanical coupling between the steering wheel and the road wheels, the steer-by-wire system is expected to not only produce the same functionality and steering feeling as conventional mechanically coupled steering systems but also implement advanced steering system features. Requirements for conventional steering functions and advanced steering features, such as adjustable steering feel, can be realized through the design of advanced control systems.

[0004] The following embodiments have been described in relation to these considerations and other general considerations. Additionally, while relatively specific problems have been discussed, it should be understood that the embodiments are not limited to solving specific problems identified in the background art. The problem to be solved

[0005] The present disclosure relates to a method and apparatus for constructing a steer-by-wire system using dual motors. means of solving the problem

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

[0007] According to various embodiments of the present disclosure, a steer-by-wire system comprises: a first power pack including a first motor, a first motor position sensor configured to detect a first power pack motor position of the first motor, a first controller configured to receive the first power pack motor position from the first motor position sensor and control the first motor, and a time generator circuit; a second power pack including a second motor, a second motor position sensor configured to detect a second power pack motor position of the second motor, and a second controller configured to receive the second power pack motor position from the second motor position sensor and control the second motor; and a steering rack operably coupled to the first motor of the first power pack and the second motor of the second power pack, the steering rack being configured to move linearly in response to rotation of at least one of the first motor and the second motor, wherein the time generator circuit of the first power pack is configured to generate motor position timing and provide it to both the first controller and the second controller, and the time generator circuit is the only motor position timestamp generating component between the first power pack and the second power pack of the steer-by-wire system.

[0008] The first power pack motor position and the second power pack motor position are generated by the first motor position sensor and the second motor position sensor, respectively, without any timestamp indicating the time when the first and second power pack motor positions are measured by the first and second motor position sensors, respectively.

[0009] The motor position timing generated by the time generator circuit of the first power pack is provided to the second controller of the second power pack through the first controller of the first power pack.

[0010] The second controller is configured to obtain a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing received from the first controller to an instance of the second power pack motor position received by the second controller from the second motor position sensor.

[0011] The instance of the second power pack motor position is received simultaneously with the motor position timing.

[0012] The instance of the second power pack motor position is received immediately after the reception of the motor position timing.

[0013] The instance of the second power pack motor position is received immediately before the reception of the motor position timing.

[0014] The first controller is further configured to obtain the first combined motor position reading including a timestamp for the first power pack by adding the motor position timing received from the first controller to an instance of the first power pack motor position received by the first controller from the first motor position sensor; and to provide the first combined motor position reading including a timestamp for the first power pack to the second controller, wherein the second controller extracts the motor position timing generated by the time generator circuit from the first combined motor position reading including a timestamp for the first power pack.

[0015] The second controller is further configured to transmit the second combined motor position reading, which includes a timestamp for the second power pack, back to the first controller.

[0016] The first controller is configured to generate a first pinion angle value using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack, and the second controller is configured to generate a second pinion angle value using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack.

[0017] The first controller is configured to detect a first mechanical defect of the first motor using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack, and the second controller is configured to detect a second mechanical defect of the second motor using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack.

[0018] The first operation of the first power pack and the second operation of the second power pack are not synchronized in time.

[0019] The motor position timing generated by the time generator circuit of the first power pack is available to the second power pack and is the sole source of motor position timing information used by it.

[0020] The first controller and the second controller: receive the first power pack motor position and the motor position timing by the first controller at a first instance in time; obtain a first combined motor position reading including a timestamp for the first power pack by adding the first power pack motor position and the motor position timing by the first controller; transmit the first combined motor position reading including a timestamp for the first power pack by the first controller to the second controller; extract the motor position timing from the first combined motor position reading including a timestamp for the first power pack by the second controller; and obtain a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing to an instance of the second power pack motor position by the second controller; and further configured to transmit the second combined motor position reading, which includes a timestamp for the second power pack, to the first controller by the second controller.

[0021] The first controller and the second controller are further configured to: manage a first operation of the first power pack by the first controller using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack; and manage a second operation of the second power pack by the second controller using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack.

[0022] The motor position timing generated by the time generator circuit of the first power pack is used as the sole timing information for synchronizing the first operation of the first power pack and the second operation of the second power pack.

[0023] The second power pack is configured without the time generator circuit and is configured to provide timing information to the second motor position measured by the second motor position sensor of the second power pack by relying solely on the time generator circuit of the first power pack.

[0024] According to various embodiments of the present disclosure, a method performed by a steer-by-wire system comprises: receiving, at a first instance in time by a first controller of a first power pack of the steer-by-wire system, a first motor position of a first motor of the first power pack measured by a first motor position sensor of the first power pack, and a motor position timing measured by a time generator circuit of the first power pack; acquiring, by the first controller, a first combined motor position reading including a timestamp for the first power pack by adding the first motor position and the motor position timing; transmitting, by the first controller, the first combined motor position reading including a timestamp for the first power pack to a second controller of a second power pack of the steer-by-wire system; and extracting the motor position timing from the first combined motor position reading including a timestamp for the first power pack by the second controller. An operation of acquiring a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing to the second motor position of the second motor of the second power pack by the second controller, wherein the second motor position is measured by the second motor position sensor of the second power pack and provided to the second controller;and may include an operation of transmitting the second coupled motor position reading, which includes a timestamp for the second power pack, to the first controller by the second controller, wherein the steer-by-wire system further includes a steering rack operably coupled to the first motor of the first power pack and the second motor of the second power pack, and the steering rack is configured to be linearly movable in response to the rotation of at least one of the first motor and the second motor, wherein the time generator circuit is the only motor position timestamp generating component between the first power pack and the second power pack of the steer-by-wire system.

[0025] The above method comprises: an operation of managing a first operation of the first power pack by the first controller using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack; and an operation of managing a second operation of the second power pack by the second controller using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack.

[0026] The first operation includes an operation of generating a first pinion angle of the first motor and an operation of detecting a first mechanical defect of the first motor, and the second operation includes an operation of generating a second pinion angle of the second motor and an operation of detecting a second mechanical defect of the second motor.

[0027] This summary is provided to introduce, in a simplified form, a set of concepts that are described in more detail in the following detailed description. This summary is not intended to identify core or essential features of the claimed invention, nor is it intended to be used to limit the scope of the claimed invention. Effects of the invention

[0028] The present disclosure may provide a method and apparatus for performing steering control operations of a vehicle using dual motors in a steer-by-wire system. Brief explanation of the drawing

[0029] Various embodiments according to the present disclosure will be described with reference to the following drawings. FIG. 1 is a schematic diagram showing a steering device according to the embodiments thereof. FIGS. 2 to 7 are plan views showing parts of a steering device according to the embodiments. FIG. 8 is a schematic diagram showing a steering device according to the embodiments thereof. FIGS. 9 to 18 are drawings showing parts of a steering device according to the embodiments of the present invention. FIG. 19 is a diagram illustrating a method for estimating a rack bar position (rack stroke range) based on the difference between the first rotation information of a first motor and the second rotation information of a second motor according to one embodiment. FIG. 20 is a schematic diagram of a vehicle including a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 21 is a perspective view of a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 22 is a cross-sectional view of a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 23 is a partial cross-sectional view of a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 24 is a drawing illustrating power packs of the steer-by-wire system of FIG. 1 to FIG. 23 according to an exemplary embodiment of the present disclosure. FIG. 25 is a data flow diagram illustrating an example of implementation according to an exemplary embodiment of the present disclosure. Corresponding numbers and symbols in different drawings generally refer to corresponding parts unless otherwise indicated. The drawings are made to clearly illustrate relevant aspects of the embodiments and are not necessarily drawn to scale. Specific details for implementing the invention

[0030] In the detailed description that follows, reference is made to the accompanying drawings, which form part of the present disclosure, in which specific embodiments in which the present invention may be practiced are illustrated in an exemplary manner. These embodiments have been described in sufficient detail to enable those skilled in the art to practice the present invention, and it should be understood that other embodiments may be utilized and structural, logical, and electrical modifications may be made without departing from the spirit and scope of the invention. Accordingly, the following detailed description should not be interpreted in a limiting sense, and the scope of the present invention is defined only by the appended claims and their equivalents. Identical numbers in the drawings indicate identical components, which will be apparent from the context of use.

[0031] A steering device according to an embodiment of the present disclosure includes 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 device (110). The ball nut (141) may be rotatably connected to a rack bar (130) by a ball (144), and may be configured so that the rack bar (130) slides axially by the rotation of the ball nut (141). The first nut pulley (143a) may be provided on the outer surface of the ball nut (141), and the second nut pulley (143b) may be provided on the outer surface of the ball nut (141). The first motor pulley (142a) may be coupled to the first motor (145) (e.g., fixed to the shaft of the first motor (145)) or formed directly on the rotatable part of the first motor (145) and connected to the first nut pulley (143a) via the first belt (149a). The second motor pulley (142b) may be coupled to the second motor (147) (e.g., fixed to the shaft of the second motor (147)) or formed directly on the rotatable part of the second motor (147) and connected to the second nut pulley (143b) via the second belt (149a). The electronic control unit (110) may include one or more controllers or processors and may be configured to control the first and second motors (145 and 147). For example, the electronic control unit (110) can output one or more control signals to the first motor (145) and the second motor (147) in response to one or more electrical signals.

[0032] Referring to FIG. 1, in the steering device according to the embodiments, an angle sensor (105) and a torque sensor (107) are coupled to one side of a steering shaft (103) connected to a steering wheel (101). Alternatively, the angle sensor (105) and the torque sensor (107) may be located around the steering shaft (103).

[0033] In an autonomous driving mode in which an autonomous driving system drives a vehicle, or in a driver assistance mode in which a driver assistance system, such as an advanced driver assistance system (ADAS), assists the driver in driving the vehicle, the electronic control unit (110) controls the steering shaft motor (120), the first motor (145), and the second motor (147) by transmitting one or more control signals in response to electrical signals transmitted from various sensors mounted on or associated with the vehicle.

[0034] Additionally, in 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 in response to an electrical signal transmitted from an angle sensor (105) that detects the operation or rotation angle of the steering wheel (101) by the driver, an electrical signal transmitted from a torque sensor (107), and an electrical signal transmitted from various other sensors mounted on or associated with the vehicle.

[0035] In the embodiments of FIG. 1, an angle sensor (105) and a torque sensor (107) are each provided as an example, but it should be noted that they may be integrated into a single torque angle sensor.

[0036] The steering shaft motor (120) may be connected to or associated with a reduction gear configured to reduce the rotational speed of the steering shaft motor (120), which includes, but is not limited to, for example, one or more gears, one or more pulleys and / or one or more belts.

[0037] The steering shaft motor (120) provides a reaction force to the steering shaft (103) so that the driver can feel a steering reaction force in the opposite direction when operating the steering wheel (101) during normal driving, thereby providing the driver with an appropriate steering sensation. Therefore, the steering shaft motor (120) may be described as a reaction force motor. However, as shown below, the steering shaft motor (120) can operate according to autonomous steering as well as provide a reaction force when operating in autonomous driving mode, so it is described as a steering shaft motor (120) instead of the term reaction force motor.

[0038] In addition, the steering shaft motor (120) rotates the steering shaft (103) so that autonomous steering is performed under the control of the electronic control unit (110) without the driver's driving or will intervening when the autonomous driving mode is operated.

[0039] Additionally, in a steer-by-wire steering system, since the steering wheel (101) is not mechanically connected to the rack bar (130) and the road wheel (131), a device may be included to mechanically limit the rotational range of the steering wheel (101) to prevent the steering shaft (103) from rotating infinitely when the driver operates the steering wheel (101).

[0040] Accordingly, in the embodiments, a rotation angle limiting device (125) that prevents infinite rotation of the steering shaft (103) may be provided. Alternatively, the rotation angle limiting device (125) may be provided to limit the rotatable range of the steering wheel (101) to prevent the steering shaft (103) from rotating infinitely.

[0041] The first motor (145) and the second motor (147) slide the rack bar (130) through the rack-by-movement device (140) to perform steering of both road wheels (131) through the tie rod (133) and knuckle arm (135).

[0042] The rack-by-movement device (140) includes a ball nut (141), a first nut pulley (143a), a second nut pulley (143b), a first motor pulley (142a), and a second motor pulley (142b). The ball nut (141) can be rotatably connected to the rack bar (130) by a ball (144), and can be configured so that the rack bar (130) slides in the axial direction of the rack bar movement device (140) by the rotation of the ball nut (141). The first nut pulley (143a) can be provided on one side of the outer surface of the ball nut (141), and the second nut pulley (143b) can be provided on the other side of the outer surface of the ball nut (141). The first motor pulley (142a) may be coupled to the first motor (145) (e.g., fixed to the shaft of the first motor (145)) or formed directly on the rotatable part of the first motor (145) and connected to the first nut pulley (143a) via the first belt (149a). The second motor pulley (142b) may be coupled to the second motor (147) (e.g., fixed to the shaft of the second motor (147)) or formed directly on the rotatable part of the second motor (147) and connected to the second nut pulley (143b) via the second belt (149a).

[0043] And, a ball (144) is coupled between the rack screw groove formed on the outer surface of the rack bar (130) and the nut screw groove formed on the inner surface of the ball nut (141), so that when the ball nut (141) rotates, the rack bar (130) slides in the axial direction.

[0044] However, for convenience of explanation, the drawings in the embodiments shown here illustrate, as an example, the angle sensor (105) and torque sensor (107) provided on the steering shaft (103), the vehicle speed sensor (102) for sending steering information to the electronic control unit (110), the ultrasonic sensor (104), and the image sensor (106). However, various other sensors such as radar and lidar may be provided, and a detailed description thereof will be omitted below.

[0045] In this steer-by-wire type steering system, since the steering wheel (101) is not mechanically connected to the rack bar (130) and the road wheel (131), a mechanical limiting device is required to prevent rotation of the rack bar (130) due to the rotational torque of the ball nut (141) rotated by the rack-by-movement device (140).

[0046] Accordingly, in the present embodiments, a rotation prevention member (150) that prevents rotation of the rack bar (130) while supporting axial sliding of the rack bar (130) may be provided.

[0047] In the embodiment illustrated in FIG. 1, a single anti-rotation member (150) is provided on one side of the rack bar (130). Alternatively, a plurality of anti-rotation members (150) may be provided to support the rack bar (130). The number of anti-rotation members (150), the axial position of the anti-rotation members (150), etc., may vary depending on the configuration and required operation of the first and second motors (145, 147), and the rotational force required for the ball nut (141) of the rack bar moving device (140).

[0048] As shown in FIG. 1, the first motor (145) and the second motor (147) can be arranged such that the axis (145a) of the first motor (145) and the axis (147a) of the second motor (147) are arranged coaxially with each other and parallel to the center axis of the rack bar (130).

[0049] In another embodiment illustrated in FIG. 2, the first motor (145) is positioned on one side of the rack bar (130) and the second motor (147) is positioned on the other side of the rack bar (130), so that the rack bar (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 positioned parallel to the central axis of the rack bar (130) and are positioned on opposite sides of the central axis of the rack bar (130).

[0050] Thus, by arranging the positions of the first motor (145) and the second motor (147) as shown in FIGS. 1 and 2, the volume of the first motor (145), the second motor (147), and the rack bar (130) becomes compact, and the assembly process of the first motor (145), the first belt (149a), the second motor (147), and the second belt (149b) can be simplified.

[0051] Referring to FIG. 3, the outer diameter (mD1) of the first motor pulley (142a) and the outer diameter (mD2) of the second motor pulley (142b) may be formed differently, and the outer diameter (nD1) of the first nut pulley (143a) and the outer diameter (nD2) of the second nut pulley (143b) may be formed identically.

[0052] That is, the first nut pulley (143a) and the second nut pulley (143b) rotate without phase difference while maintaining the same phase angle when the first motor (145) and the second motor (147) are operated, and the first motor pulley (142a) and the second motor pulley (142b) rotate while the phase difference gradually changes when the first motor (145) and the second motor (147) are operated.

[0053] Here, the first nut pulley (143a) and the second nut pulley (143b) are shown in FIG. 3 as being formed separately and coupled to one side and the other side of the outer surface of the ball nut (141), but as shown in FIG. 4, the outer diameters of the first nut pulley (143a) and the second nut pulley (143b) can be formed integrally with the same diameter, and this will be described later.

[0054] The first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0055] The first motor sensor (145s) detects the direction and angle of rotation of the shaft (145a) of the first motor (145) when the first motor (145) is operated and transmits it to the electronic control unit (110).

[0056] When the second motor (147) is operated, the second motor sensor (147s) detects the rotation direction and rotation angle of the shaft (147a) of the second motor (147), and the second motor sensor (147s) outputs a signal indicating the rotation direction and rotation angle of the shaft (147a) of the second motor (147) to the electronic control unit (110). The second motor sensor (147s) detects the direction and angle of rotation of the shaft (147a) of the second motor (147) when the second motor (147) is operated and transmits it to the electronic control unit (110).

[0057] Accordingly, the electronic control unit (110) can determine the sliding position of the rack bar (130) based on the first position value of the shaft (145a) of the first motor (145) detected by the first motor sensor (145s) and the second position value of the shaft (147a) of the second motor (147) detected by the second motor sensor (147s), and output a control signal to the first motor (145) and the second motor (147).

[0058] That is, the electronic control unit (110) sets the angle formed by the reference point of the axis (145a) of the first motor (145) when the first motor (145) is stopped and the reference point of the axis (147a) of the second motor (147) when the second motor (147) is stopped as the reference position value, and sets the angle formed by the reference point of the axis (145a) of the first motor (145) and the reference point of the axis (147a) of the second motor (147) after the first motor (145) and the second motor (147) are operated as the operating position value, and calculates the sliding position of the rack bar (130) based on the difference between the reference position value and the operating position value.

[0059] Here, the difference between the reference position value and the operating position value can be formed from 0° to 360°, and the maximum sliding amount of the rack bar (130) is set within this range, and the electronic control device (110) calculates the sliding position of the rack bar (130) based on at least one of the rotation ratio of the first motor pulley (142a) and the first nut pulley (143a), the rotation ratio of the second motor pulley (142b) and the second nut pulley (143b), the outer diameter and inner diameter of the ball nut (141), the outer diameter of the rack bar (130), and the lead angle of the rack screw groove and the nut screw groove.

[0060] Additionally, the electronic control unit (110) may set the difference between the reference position value and the operating position value as a movement value and calculate the sliding position of the rack bar (130) by comparing it with preset data, in which case the movement value can be formed from 0° to 360° and the maximum sliding amount of the rack bar (130) is set within this range.

[0061] Here, the preset data may be data that stores the sliding amount of the rack bar (130) corresponding to a movement value calculated based on at least one of the outer diameters of the first motor pulley (142a) and the second motor pulley (142b), the outer diameters of the first nut pulley (143a) and the second nut pulley (143b), the outer and inner diameters of the ball nut (141), and the outer diameter of the rack bar (130).

[0062] For example, the first motor pulley (142a) and the second motor pulley (142b) may have different outer diameters, and the first nut pulley (143a) and the second nut pulley (143b) may have the same outer diameter. In this way, the electronic control unit (110) can determine the sliding position of the rack bar (130) based on the first position value of the shaft (145a) of the first motor (145) detected by the first motor sensor (145s) and the second position value of the shaft (147a) of the second motor (147) detected by the second motor sensor (147s), and output a signal to control the first motor (145) and the second motor (147).

[0063] Referring to FIG. 4, the outer diameters of the first nut pulley (143a) and the second nut pulley (143b) can be formed integrally with the same diameter.

[0064] In this case, when the first nut pulley (143a) and the second nut pulley (143b) are formed integrally with the same outer diameter, the first belt (149a) is connected to one side of the integrally formed pulley and the second belt (149a) is connected to the other side, so that they can be connected to the first motor pulley (142a) and the second motor pulley (142b), respectively.

[0065] Additionally, the first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0066] The first motor sensor (145s) detects the direction and angle of rotation of the shaft (145a) of the first motor (145) when the first motor (145) is operated and transmits it to the electronic control unit (110).

[0067] The second motor sensor (147s) detects the direction and angle of rotation of the shaft (147a) of the second motor (147) when the second motor (147) is operated and transmits it to the electronic control unit (110).

[0068] Accordingly, the electronic control unit (110) can control the output value transmitted to the first motor (145) and the second motor (147) by calculating the sliding position of the rack bar (130) based on the first position value of the shaft (145a) of the first motor (145) received from the first motor sensor (145s) and the second position value of the shaft (147a) of the second motor (147) received from the second motor sensor (147s).

[0069] Referring to FIG. 5, the outer diameter (mD1) of the first motor pulley (142a) and the outer diameter (mD2) of the second motor pulley (142b) are formed identically, while the outer diameter (nD1) of the first nut pulley (143a) and the outer diameter (nD2) of the second nut pulley (143b) may be formed differently.

[0070] Since the first nut pulley (143a), the second nut pulley (143b), and the ball nut (141) must rotate at the same speed, the first nut pulley (143a) and the second nut pulley (143b) maintain the same phase angle and rotate without phase difference when the first motor (145) and the second motor (147) are operated, and the first motor pulley (142a) and the second motor pulley (142b) rotate with a gradually changing phase difference.

[0071] Additionally, the first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0072] The first motor sensor (145s) detects the direction and angle of rotation of the shaft (145a) of the first motor (145) when the first motor (145) is operated, and transmits a signal indicating the rotation direction and rotation angle of the shaft (145a) of the first motor (145) to the electronic control unit (110).

[0073] And, the second motor sensor (147s) detects the direction and angle of rotation of the shaft (147a) of the second motor (147) when the second motor (147) is operated and transmits it to the electronic control unit (110).

[0074] Accordingly, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s) through the calculation process described above, and control the output value transmitted to the first motor (145) and the second motor (147).

[0075] Referring to FIG. 6, the outer diameter (mD1) of the first motor pulley (142a) and the outer diameter (mD2) of the second motor pulley (142b) may be formed differently, and the outer diameter (nD1) of the first nut pulley (143a) and the outer diameter (nD2) of the second nut pulley (143b) may also be formed differently.

[0076] In this case as well, since the first nut pulley (143a), the second nut pulley (143b), and the ball nut (141) must rotate at the same speed, the first nut pulley (143a) and the second nut pulley (143b) maintain the same phase angle and rotate without phase difference when the first motor (145) and the second motor (147) are operated.

[0077] And, the first motor pulley (142a) and the second motor pulley (142b) rotate with a phase difference that gradually changes when the first motor (145) and the second motor (147) are operated.

[0078] The first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0079] Accordingly, the electronic control unit (110) can control the output value transmitted to the first motor (145) and the second motor (147) by calculating the sliding position of the rack bar (130) through the calculation process described above based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s).

[0080] Referring to FIG. 7, a first motor pulley (142-1) is provided on the outer surface of the first motor pulley (142a) and a first nut pulley (143-1) is provided on the outer surface of the first nut pulley (143a) so as to be coupled with a first belt (149-1) provided on the inner surface of the first belt (149a).

[0081] The first motor pulley (142-1) and the first nut pulley (143-1) are connected to the first belt tooth (149-1) to transmit power, so they are formed with a tooth shape of the same size as the first belt tooth (149-1).

[0082] A second motor pulley (142-2) is provided on the outer surface of the second motor pulley (142b), and a second nut pulley (143-2) is provided on the outer surface of the second nut pulley (143b), so that they can be combined with a second belt (149-2) provided on the inner surface of the second belt (149a).

[0083] Since the second motor pulley (142-2) and the second nut pulley (143-2) must be coupled to the second belt tooth (149-2) to transmit power, they are formed with a tooth shape of the same size as the second belt tooth (149-2).

[0084] Also, the number of the first motor pulley reach (142-1) and the second motor pulley reach (142-2) may be formed differently, and the number of the first nut pulley reach (143-1) and the second nut pulley reach (143-2) may be formed identically.

[0085] That is, the first motor pulley reach (142-1) and the second motor pulley reach (142-2) are formed with the same circumferential pitch as the gear module but with different pitch circle diameters and number of teeth, and the first nut pulley reach (143-1) and the second nut pulley reach (143-2) are formed with the same circumferential pitch as the gear module but with the same pitch circle diameters and number of teeth.

[0086] The first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0087] Accordingly, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s), and control the output value transmitted to the first motor (145) and the second motor (147).

[0088] That is, as with the calculation method described above, the difference between the reference position value and the operating position value can be formed from 0° to 360°, and the maximum sliding amount of the rack bar (130) is set within this range, and the electronic control device (110) calculates the sliding position of the rack bar (130) based on at least one of the pitch circle diameter ratio or tooth ratio of the first motor pulley (142a) and the first nut pulley (143a), the pitch circle diameter ratio or tooth ratio of the second motor pulley (142b) and the second nut pulley (143b), the outer diameter and inner diameter of the ball nut (141), and the outer diameter of the rack bar (130).

[0089] Additionally, the electronic control unit (110) may set the difference between the reference position value and the operating position value as a movement value, as in the calculation method described above, and calculate the sliding position of the rack bar (130) by comparing it with preset data. In this case, the movement value can be formed from 0° to 360°, and the maximum sliding amount of the rack bar (130) is set within this range.

[0090] Here, the preset data may be data that stores the sliding amount of the rack bar (130) corresponding to a movement value calculated based on at least one of the pitch circle diameter and number of teeth of the first motor pulley (142a) and the second motor pulley (142b), the pitch circle diameter and number of teeth of the first nut pulley (143a) and the second nut pulley (143b), the outer diameter and inner diameter of the ball nut (141), and the outer diameter of the rack bar (130).

[0091] Thus, by forming the first motor pulley reach (142-1) and the second motor pulley reach (142-2) differently and the first nut pulley reach (143-1) and the second nut pulley reach (143-2) equally, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s), and control the output value transmitted to the first motor (145) and the second motor (147).

[0092] Additionally, the number of the first motor pulley reach (142-1) and the second motor pulley reach (142-2) may be formed to be the same, and the number of the first nut pulley reach (143-1) and the second nut pulley reach (143-2) may be formed to be different.

[0093] The first motor pulley reach (142-1) and the second motor pulley reach (142-2) are formed with the same circumferential pitch as the gear module, and the same pitch circle diameter and number of teeth, and the first nut pulley reach (143-1) and the second nut pulley reach (143-2) are formed with the same circumferential pitch as the gear module, but the same pitch circle diameter and number of teeth.

[0094] Additionally, the first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0095] Accordingly, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s) through the calculation process described above, and control the output value transmitted to the first motor (145) and the second motor (147).

[0096] In addition, the number of the first motor pulley reach (142-1) and the second motor pulley reach (142-2) may be formed differently, and the number of the first nut pulley reach (143-1) and the second nut pulley reach (143-2) may also be formed differently.

[0097] That is, the first motor pulley reach (142-1) and the second motor pulley reach (142-2) are formed with the same circumferential pitch as the gear module but with different pitch circle diameters and number of teeth, and the first nut pulley reach (143-1) and the second nut pulley reach (143-2) are formed with the same circumferential pitch as the gear module but with different pitch circle diameters and number of teeth.

[0098] Additionally, the first motor (145) may be equipped with a first motor sensor (145s) that detects the rotational position of the shaft (145a) of the first motor (145), and the second motor (147) may be equipped with a second motor sensor (147s) that detects the rotational position of the shaft (147a) of the second motor (147).

[0099] Accordingly, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the first position value transmitted from the first motor sensor (145s) and the second position value transmitted from the second motor sensor (147s) through the calculation process described above, and control the output value transmitted to the first motor (145) and the second motor (147).

[0100] Referring to FIG. 8, in case either the first motor sensor (145s) or the second motor sensor (147s) becomes inoperable, a separate rotating gear (139) that rotates by meshing with the rack gear (130b) is installed on one side of the rack bar (130), and a rotation angle sensor (137s) that detects the rotation angle of the rotating gear (139) may be provided.

[0101] The rotating gear (139) can be installed to be supported in a rack housing (not shown) via a bearing (not shown) and to rotate, and the rotation angle sensor (137s) can be installed on the shaft (137) of the rotating gear (139) to detect the rotation angle of the rotating gear (139) and transmit it to the electronic control unit (110).

[0102] Accordingly, even if either the first motor sensor (145s) or the second motor sensor (147s) becomes inoperable, the electronic control unit (110) can calculate the sliding position of the rack bar (130) based on the pre-stored gear ratio of the rack gear (130b) and the rotation angle received from the rotation angle sensor (137s) and control the output value transmitted to the first motor (145) and the second motor (147).

[0103] Meanwhile, various embodiments of a rotation prevention member that can be provided in the aforementioned steering device will be described below with reference to the drawings.

[0104] Referring to FIGS. 9 to 18, the anti-rotation member (150) in the embodiments described above will be examined in more detail as follows.

[0105] As shown in FIG. 9, the anti-rotation member (150) is coupled to one side and the other side of the rack bar (130) in the radial direction to support the rack bar (130) from both sides, thereby preventing the rack bar (130) from rotating about the central axis.

[0106] The anti-rotation member (150) may include a shaft (230) that supports a support surface (130-1) formed on the outer surface of a rack bar (130), and a support yoke (240) that supports the outer surface of a rack bar (130) opposite to the position where the shaft (230) is supported.

[0107] The support surface (130-1) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0108] This support surface (130-1) is formed by being recessed on the outer surface of the rack bar (130) and can be formed as a curved or flat surface.

[0109] The support surface (130-1) is formed to be long in the axial direction so that it can be supported on the shaft (230) when the rack bar (130) slides in the axial direction.

[0110] The support surface (130-1) may be provided with a coating layer formed of a low-friction material having a low coefficient of friction, such as fluoropolymer or ceramic, to minimize friction with the shaft (230).

[0111] The shaft (230) supporting the support surface of the rack bar (130) may largely include an upper support portion (231), a body portion (233), and a lower support portion (235).

[0112] The shaft (230) is supported by the rack housing (see 160 in FIG. 10) when the rack bar (130) slides, and as it rotates, the body part (233) supports the support surface (130-1), thereby preventing the rack bar (130) from rotating.

[0113] A needle bearing (236) may be attached to the body part (233) to minimize friction with the support surface (130-1).

[0114] An upper support member (231) with an enlarged diameter is provided on the upper side of the body member (233), and an upper bearing (234) can be coupled to the upper support member (231) to be rotatably supported on the rack housing.

[0115] A top plug (232) may be attached to the upper side of the upper support member (231) to prevent foreign substances from the outside from entering the rack housing.

[0116] A lower support member (235) with a reduced diameter is provided on the lower side of the body member (233), and a lower bearing (238) can be coupled to the lower support member (235) to be rotatably supported on the rack housing.

[0117] A support yoke (240) that supports the outer surface of the rack bar (130) opposite the position where the shaft (230) is supported prevents rotation of the rack bar (130) by supporting the rack bar (130) toward the shaft (230) when the rack bar (130) slides.

[0118] The support yoke (240) may have a curved support portion (241) formed at its end with a curve identical to the outer surface of the rack bar (130) so as to be closely supported on the outer surface of the rack bar (130).

[0119] Since the support yoke (240) is required to have a certain degree of rigidity and elasticity, it may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0120] An elastic ring (245) can be attached to the outer surface of the support yoke (240) to prevent rattle noise with the rack housing.

[0121] One or more elastic rings (245) may be attached to the outer surface of the support yoke (240).

[0122] Since the elastic ring (245) is required to be formed of a material capable of absorbing vibration and noise while having a predetermined elasticity and rigidity, it may be formed of one or more materials selected from the group consisting of NR (Natural Rubber), NBR (Nitrile Butadiene Rubber), CR (Chloroprene Rubber), EPDM (Ethylene Propylene Terpolymer), FPM (Fluoro Rubber), SBR (Styrene Butadine Rubber), CSM (Chlorosulphonated Polyethylene), urethane, silicone, etc., which have such properties.

[0123] A yoke plug (243) that is press-fitted or screw-coupled to the rack housing to fix the position of the support yoke (240) may be attached to the end of the support yoke (240).

[0124] Additionally, an elastic body is combined between the support yoke (240) and the yoke plug (243) to elastically support the support yoke (240) toward the rack bar (130).

[0125] As shown in FIG. 10, the anti-rotation member (150) is coupled to one side and the other side of the rack bar (130) in the radial direction to support the rack bar (130) from both sides, thereby preventing the rack bar (130) from rotating about the central axis.

[0126] The anti-rotation member (150) may include a needle bearing (220) that supports a support surface (130-1) formed on the outer surface of a rack bar (130), a support yoke (225) to which the needle bearing (220) is rotatably coupled, and a rack bush (229) that supports the outer surface of the rack bar (130) opposite to the position where the needle bearing (220) is supported.

[0127] The support surface (130-1) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0128] This support surface (130-1) is formed by being recessed on the outer surface of the rack bar (130) and can be formed as a curved or flat surface.

[0129] The support surface (130-1) is formed to be long in the axial direction so that it can be supported by the needle bearing (220) when the rack bar (130) slides in the axial direction.

[0130] The support surface (130-1) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the needle bearing (220).

[0131] A needle bearing (220) supporting the support surface (130-1) of a rack bar (130) has a support shaft (221) provided at its center and fixed to the support yoke (225) so that it can be rotatably supported on the support yoke (225).

[0132] The outer ring (222) of the needle bearing (220) is supported on the support surface (130-1) during sliding of the rack bar (130) and rotates, thereby preventing the rack bar (130) from rotating.

[0133] The outer ring (222) of the needle bearing (220) can be positioned at a location protruding from the end of the support yoke (225) so as to be supported on the support surface (130-1).

[0134] The support yoke (225) prevents rotation of the rack bar (130) by supporting the needle bearing (220) toward the support surface (130-1) when the rack bar (130) slides.

[0135] Since the support yoke (225) is required to have a certain degree of rigidity and elasticity, it may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0136] An elastic ring (226) can be attached to the outer surface of the support yoke (225) to prevent rattle noise with the rack housing (160).

[0137] One or more elastic rings (226) may be attached to the outer surface of the support yoke (225).

[0138] Since the elastic ring (226) is required to be formed of a material capable of absorbing vibration and noise while having a certain elasticity and rigidity, it may be formed of one or more materials selected from the group consisting of NR (Natural Rubber), NBR (Nitrile Butadiene Rubber), CR (Chloroprene Rubber), EPDM (Ethylene Propylene Terpolymer), FPM (Fluoro Rubber), SBR (Styrene Butadine Rubber), CSM (Chlorosulphonated Polyethylene), urethane, silicone, etc., which have such properties.

[0139] A yoke plug (227) that fixes the position of the support yoke (225) by being press-fitted or screw-coupled to the rack housing (160) can be attached to the end of the support yoke (225).

[0140] Additionally, an elastic body (228) is combined between the support yoke (225) and the yoke plug (227) to elastically support the support yoke (225) toward the rack bar (130).

[0141] The rack bushing (229) supporting the outer surface of the rack bar (130) opposite the position where the needle bearing (220) is supported may be formed in a semi-cylindrical shape with a portion of the outer surface cut out.

[0142] The rack bush (229) prevents rotation of the rack bar (130) by supporting the rack bar (130) toward the radial needle bearing (220) when the rack bar (130) slides.

[0143] The rack bush (229) can be formed with the same curve as the outer surface of the rack bar (130) so as to be closely supported on the outer surface of the rack bar (130).

[0144] A bushing connection groove (166-1) to which a rack bushing (229) is connected may be formed on the inner surface of the rack housing (160).

[0145] The rack bush (229) may have a fixing projection (229a) formed on the outer surface of the end to prevent the rack bar (130) from shifting its axial position or rotating when sliding.

[0146] A fixing groove (166-2) to which a fixing projection (229a) is coupled may be formed on the inner surface of the rack housing (160).

[0147] Since the rack bush (229) is required to have a certain degree of rigidity and elasticity, it may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0148] As shown in FIG. 11, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing (160) and can prevent the rack bar (130) from rotating about the central axis.

[0149] The anti-rotation member (150) may include a support member (210) having one end supported in a rack support groove (132) formed on the outer surface of a rack bar (130) and the other end supported in a housing groove (162) formed on the inner surface of a rack housing (160), and an elastic member (212) coupled to the support member (210) to elastically support the inner surface of the rack housing (160).

[0150] The rack support groove (132) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0151] These rack support grooves (132) are formed by being recessed on the outer surface of the rack bar (130) and can be formed as curved or flat surfaces.

[0152] The rack support groove (132) is formed axially so that it can be supported by the support member (210) when the rack bar (130) slides axially.

[0153] The rack support groove (132) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the support member (210).

[0154] A housing groove (162) is formed at a position facing the rack support groove (132) in the radial direction, in which the other end of the support member (210) is supported.

[0155] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0156] These housing grooves (162) are formed to be recessed on the inner circumference of the rack housing (160) so as to prevent the support member (210) from rotating the rack bar (130) when the rack bar (130) slides in the axial direction, and can be formed as curved or flat surfaces.

[0157] The support member (210) has one end and the other end connected to the rack support groove (132) and the housing groove (162), and a connecting groove (211) is formed at the other end to which an elastic member (212) is connected.

[0158] Since the support member (210) is required to have a certain degree of rigidity and elasticity, it may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0159] The elastic member (212) is coupled to the coupling groove (211) of the support member (210) and elastically supported on the inner surface of the rack housing (160), thereby supporting the support member (210) toward the rack bar (130), so that when the rack bar (130) slides in the axial direction, the support member (210) does not collide with the inner surface of the rack housing (160), thereby maintaining a certain distance. Thus, rattle noise between the support member (210) and the rack housing (160) can be prevented.

[0160] The elastic member (212) can be formed from an arched thin plate.

[0161] A plug bolt (215) for preventing the support member (210) from detaching may be coupled to the inner surface of the rack housing (160) at the axial end of the support member (210). The plug bolt (215) may be coupled by press-fitting it into the inner surface of the rack housing (160).

[0162] The plug bolt (215) includes a support portion (215a) that supports the support member (210) in the axial direction, and a fixing portion (215b) that is connected to the support portion (215a) and fixed to the inner circumference of the rack housing (160).

[0163] A screw portion is formed on the outer surface of the fixed portion (215b) so that it can be screw-coupled to the inner surface of the rack housing (160).

[0164] Additionally, a fixing member (217) can be attached to the axial end of the plug bolt (215) to prevent loosening and detachment of the plug bolt (215).

[0165] The fixing member (217) may have a fixing projection (217a) formed to protrude radially on the outer surface.

[0166] A fixing groove (164) may be formed on the inner surface of the rack housing (160) in which a fixing projection (217a) of a fixing member (217) is inserted and supported.

[0167] As illustrated in FIG. 12, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing, and can prevent the rack bar (130) from rotating about a central axis.

[0168] The anti-rotation member (150) may include a support bush (205) that supports a support surface (130-1) formed on the outer surface of a rack bar (130), a bush holder (200) that is coupled to the outer surface of the rack bar (130) and has the support bush (205) supported on its inner surface, and an elastic member (207) that is coupled between the bush holder (200) and the support bush (205) to elastically support the support bush (205) toward the rack bar (130).

[0169] The support surface (130-1) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0170] This support surface (130-1) is formed by being recessed on the outer surface of the rack bar (130) and can be formed as a curved or flat surface.

[0171] The support surface (130-1) is formed to be long in the axial direction so that it can be supported by the support bush (205) when the rack bar (130) slides in the axial direction.

[0172] The support surface (130-1) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the support bush (205).

[0173] A housing groove (162) is formed on the inner surface of the rack housing (160) at a position facing the support surface (130-1) in the radial direction, to which a bush holder (200) is coupled and supported.

[0174] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0175] These housing grooves (162) are formed by being recessed into the inner surface of the rack housing (160) and can be formed as curved or flat surfaces.

[0176] Additionally, a stepped portion (163) is formed on the inner surface of the rack housing (160) such that the diameter is expanded at the end of the housing groove (162), and the end of the stepped portion (163) may be formed to be open in the axial direction.

[0177] The bush holder (200) has a cylinder shape with one side cut in the radial direction, and an inner protruding surface is formed at a position facing the cut portion to protrude radially inward.

[0178] Additionally, a bushing coupling groove (203) to which a support bushing (205) is coupled is formed on the inner protruding surface (201), and a flange portion (206) that protrudes radially and is supported by the stepped portion (163) of the rack housing (160) may be formed at the axial end of the bushing holder (200).

[0179] The flange portion (206) is supported by the step portion (163) and prevents the bush holder (200) from coming off when the rack bar (130) slides axially.

[0180] The support bush (205) coupled to the bush coupling groove (203) of the bush holder (200) includes a protruding support portion (205a) formed to protrude from the center and to which an elastic member (207) is coupled.

[0181] The elastic member (207) is formed in an annular shape, and the inner and outer surfaces are formed in a cone shape with axial steps, so that the protruding support member (205a) can be coupled to the inner surface of the elastic member (207).

[0182] This elastic member (207) elastically supports the support bush (205) toward the rack bar (130) between the bush holder (200) and the support bush (205), thereby maintaining a certain distance (202) so that the support bush (205) does not collide with the bush holder (200) when the rack bar (130) slides axially. Thus, rattle noise between the support bush (205) and the bush holder (200) can be prevented.

[0183] Since these bush holders (200) and support bushes (205) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0184] As shown in FIG. 13, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing (160) and can prevent the rack bar (130) from rotating about the central axis.

[0185] The anti-rotation member (150) may include a rack bush (250) having an inner support member (251) supported by a rack support groove (132) formed on the outer surface of a rack bar (130) and an outer support member (253) supported by a housing groove (162) formed on the inner surface of a rack housing (160), and an elastic member (252) coupled to the outer surface of the rack bush (250) to elastically support the rack bush (250).

[0186] The rack support groove (132) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0187] These rack support grooves (132) are formed by being recessed on the outer surface of the rack bar (130) and can be formed as curved or flat surfaces.

[0188] The rack support groove (132) is formed to be long in the axial direction so that it can be supported by the rack bushing when the rack bar (130) slides in the axial direction.

[0189] The rack support groove (132) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the rack bush (250).

[0190] An inner support portion (251) is formed on the inner surface of the rack bushing (250) at a position facing the rack support groove (132) in the radial direction, protruding inward in the radial direction.

[0191] An outer support portion (253) is formed on the outer surface of the rack bush (250) to protrude radially outward and is coupled to the housing groove (162).

[0192] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0193] The housing groove (162) is formed as a recess on the inner surface of the rack housing (160) and can be formed as a curved or flat surface.

[0194] The outer support members (253) are spaced out in the circumferential direction from the outer surface of the rack bush (250), and two or more may be formed.

[0195] The outer support member (253) may be formed as a pair on both sides in the circumferential direction at a position facing the inner support member (251) on the outer surface of the rack bush (250).

[0196] Since such rack bushings (250) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0197] The elastic member (252) coupled to the outer surface of the rack bush (250) can be formed in a ring shape.

[0198] Since the elastic member (252) is required to be formed of a material capable of absorbing vibration and noise while having a predetermined elasticity and rigidity, it may be formed of one or more materials selected from the group consisting of NR (Natural Rubber), NBR (Nitrile Butadiene Rubber), CR (Chloroprene Rubber), EPDM (Ethylene Propylene Terpolymer), FPM (Fluoro Rubber), SBR (Styrene Butadine Rubber), CSM (Chlorosulphonated Polyethylene), urethane, silicone, etc., which have such properties.

[0199] A coupling groove (252-1) to which an elastic member (252) is coupled may be formed on the outer surface of the rack bush (250).

[0200] The rack bush (250) may have an axially cut section (254) formed to facilitate elastic deformation in the radial direction.

[0201] The incisions (254) are spaced apart in the circumferential direction, and two or more may be formed.

[0202] The cut portion (254) may be formed so that one end of the rack bush (250) is open or the other end is open.

[0203] The incision (254) formed with one end open and the incision (254) formed with the other end open may be spaced apart in the circumferential direction and formed staggered from each other.

[0204] Accordingly, by elastically supporting the rack bush (250) in the radial direction by the tightening force of the elastic member (252), a certain distance is maintained so that the rack bush (250) does not collide with the rack housing (160) when the rack bar (130) slides in the axial direction. Thus, rattle noise between the rack bush (250) and the rack housing (160) can be prevented.

[0205] As shown in FIG. 14, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing (160) and can prevent the rack bar (130) from rotating about the central axis.

[0206] The anti-rotation member (150) may include a rotating member (191) that supports a supporting surface (130-1) formed on the outer surface of a rack bar (130), and a support bush (190) that is rotatably coupled to the rotating member (191) and coupled to a housing groove (162) formed on the inner surface of a rack housing (160).

[0207] The support surface (130-1) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0208] This support surface (130-1) is formed by being recessed on the outer surface of the rack bar (130) and can be formed as a curved or flat surface.

[0209] The support surface (130-1) is formed to be long in the axial direction so that it can be supported by the rotating member (191) when the rack bar (130) slides in the axial direction.

[0210] Two or more support surfaces (130-1) may be formed on the outer surface of the rack bar (130) at circumferentially spaced apart.

[0211] The support surfaces (130-1) can be formed as a pair at positions facing each other in the radial direction of the rack bar (130).

[0212] The rotating member (191) may be a roller or ball that is coupled to the inner surface of the support bush (190) and supported on the support surface (130-1) of the rack bar (130).

[0213] The rotating member (191) can be connected to both the inner and outer sides of the support bush (190).

[0214] The support surface (130-1) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the rotating member (191).

[0215] A housing groove (162) is formed on the inner surface of the rack housing (160) at a position facing the support surface rotating member (191) in the radial direction, to which a support bush (190) is coupled and supported.

[0216] The support bush (190) is rotatably coupled to the rotating member (191) and coupled to the housing groove (162) of the rack housing (160).

[0217] Since such support bushes (190) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0218] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0219] These housing grooves (162) are formed by being recessed into the inner surface of the rack housing (160) and can be formed as curved or flat surfaces.

[0220] As shown in FIG. 15, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing, and can prevent the rack bar (130) from rotating about the central axis.

[0221] The anti-rotation member (150) may include a rack bushing (180) having a rotational support member (183) that is coupled to a rack support groove (132) formed on the outer surface of a rack bar (130) and a housing groove (162) formed on the inner surface of a rack housing (160) to provide rotational support, an elastic support member (185) that is coupled to a rack support groove (132) formed on the outer surface of a rack bar (130) and a housing groove (162) formed on the inner surface of a rack housing (160) to provide elastic support, and a connecting member (181) that connects the rotational support member (183) and the elastic support member (185).

[0222] The rack support groove (132) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0223] These rack support grooves (132) are formed by being recessed on the outer surface of the rack bar (130) and can be formed as curved or flat surfaces.

[0224] The rack support groove (132) is formed to be elongated in the axial direction so that it can be supported by the rotational support member (183) and the elastic support member (185) when the rack bar (130) slides in the axial direction. The rotational support member (183) and the elastic support member (185) can be placed in the rack support groove (132).

[0225] A housing groove (162) is formed on the inner surface of the rack housing (160) at a position facing the rack support groove (132) in the radial direction.

[0226] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0227] The housing groove (162) is formed as a recess on the inner surface of the rack housing (160) and can be formed as a curved or flat surface.

[0228] The rack support groove (132) and the housing groove (162) may be provided with a coating layer formed of a low-friction material, such as fluoropolymer or ceramic, to minimize friction with the rack bush (180).

[0229] The rack bush (180) may be provided with two or more rotational support members (183). And / or the rack bush (180) may be provided with two or more elastic support members (185).

[0230] A ball may be coupled to the rotational support member (183), and two or more balls may be coupled and spaced apart in the axial direction.

[0231] The elastic support member (185) may have a cylindrical shape. The elastic support member (185) may have an opening on one side.

[0232] By elastically supporting the rack bush (180) in the rack support groove (132) and the housing groove (162) by the elastic deformation force of the elastic support member (185), a certain distance is maintained so that the rack bush (180) does not collide with the rack housing (160) when the rack bar (130) slides in the axial direction. Therefore, rattle noise between the rack bush (180) and the rack housing (160) can be prevented.

[0233] As shown in FIG. 16, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the inner surface of the rack housing (160) and can prevent the rack bar (130) from rotating about the central axis.

[0234] The anti-rotation member (150) may include a rack bushing (170) having a first support member (171) that supports a support surface (130-1) formed on the outer surface of a rack bar (130), and a second support member (175) that is connected to the first support member (171), supports the outer surface of the rack bar (130), and has a fixing projection (173) formed on the outer surface that is coupled to a housing groove (162) formed on the inner surface of a rack housing (160).

[0235] The support surface (130-1) formed on the outer surface of the rack bar (130) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0236] This support surface (130-1) is formed by being recessed on the outer surface of the rack bar (130) and can be formed as a curved or flat surface.

[0237] The support surface (130-1) is formed to be long in the axial direction so that it can be supported by the first support part (171) when the rack bar (130) slides in the axial direction.

[0238] The first support member (171) is supported such that its inner surface (171a) is in close contact with the support surface (130-1) of the rack bar (130), and its outer surface may be spaced apart from the inner surface of the rack housing (160).

[0239] A coating layer formed of a low-friction material, such as fluoropolymer or ceramic, may be provided on the support surface (130-1) and the outer surface of the rack bar to minimize friction with the rack bush (170).

[0240] The second support member (175) is connected to the first support member (171) in a circumferential direction and is formed to wrap around the outer surface of the rack bar (130).

[0241] The outer surface of the second support member (175) is provided with a fixing projection (173) formed to protrude radially.

[0242] A housing groove (162) is formed on the inner surface of the rack housing (160) so that the fixing projection (173) of the second support part (175) is coupled thereto to prevent the rack bushing (170) from rotating.

[0243] The housing groove (162) can be formed by cutting or grinding the inner surface of the rack housing (160).

[0244] These housing grooves (162) are formed by being recessed into the inner surface of the rack housing (160) and can be formed as curved or flat surfaces.

[0245] Since such rack bushings (170) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0246] As shown in FIG. 17, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the guide cover (155) coupled to the rack housing (160), and can prevent the rack bar (130) from rotating about the central axis.

[0247] The anti-rotation member (150) may include a support member (151) coupled to the outer surface of the rack bar (130), a guide cover (155) coupled to the rack housing (160) and having the support member (151) supported on its inner surface, and a fastening member (159) that fixes the guide cover (155) to the rack housing (160).

[0248] A support member (151) is attached to the outer surface of the rack bar (130). The support member (151) is attached to a coupling groove (134) formed on the outer surface of the rack bar (130) by press-fitting or bonding, and the coupling groove (134) can be formed by cutting or grinding the outer surface of the rack bar (130).

[0249] These connecting grooves (134) are formed by being recessed on the outer surface of the rack bar (130) and can be formed as curved or flat surfaces.

[0250] A rack housing (160) located radially opposite to a support member (151) is formed to be open, and a guide cover (155) is attached to the open portion.

[0251] A support groove (155-1) in which a support member (151) is inserted and supported may be formed on the inner surface of the guide cover (155).

[0252] These support grooves (155-1) are formed axially so that the support member (151) can be supported when the rack bar (130) slides axially.

[0253] The support groove (155-1) can be formed in a trapezoidal shape that widens toward the support member (151).

[0254] The support member (151) can be formed in a trapezoidal shape that becomes narrower in width as it goes from the outer surface of the rack bar (130) toward the support groove (155-1).

[0255] Both sides of the support groove (155-1) are in close contact with and supported by the support member (151), and the inner side of the support groove (155-1) may be spaced apart from the end of the support member (151).

[0256] A coating layer formed of a low-friction material, such as fluoropolymer or ceramic, may be provided on the support groove (155-1) or the support member (151) to minimize friction.

[0257] The support groove (155-1) can be filled with grease to minimize friction with the support member (151).

[0258] The guide cover (155) can be fixed to the rack housing (160) by a fastening member (159).

[0259] Additionally, a fastening member (159) passes through between the guide cover (155) and the rack housing (160), and an elastic member (157) that elastically supports the guide cover (155) and the rack housing (160) can be coupled.

[0260] A sealing member (158) that prevents moisture or dust from entering from the outside may be applied to the end of the guide cover (155) and the outer surface of the rack housing (160).

[0261] Since these support members (151) and guide covers (155) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0262] As illustrated in FIG. 18, the anti-rotation member (150) is supported on the outer surface of the rack bar (130) and the housing cover (154) which is coupled to the rack housing (160), and can prevent the rack bar (130) from rotating about the central axis.

[0263] The anti-rotation member (150) may include a support member (151) supported on the outer surface of the rack bar (130), a housing cover (154) fixed to the rack housing (160) and having the support member (151) coupled to its inner surface, and a fastening member (159) that fixes the housing cover (154) to the rack housing (160).

[0264] A rack support groove (134) is formed on the outer surface of the rack bar (130) to support a support member (151).

[0265] The rack support groove (134) is formed to be long in the axial direction so that the support member (151) can be supported when the rack bar (130) slides in the axial direction.

[0266] These rack support grooves (134) are formed by being recessed on the outer surface of the rack bar (130) and can be formed as curved or flat surfaces.

[0267] A rack housing (160) located radially opposite to the rack support groove (134) is formed to be open, and a housing cover (154) is attached to the open portion.

[0268] A cover support groove (156) to which a support member (151) is coupled may be formed on the inner surface of the housing cover (154).

[0269] The rack support groove (134) can be formed in a trapezoidal shape that widens toward the housing cover (154).

[0270] The support member (151) can be formed in a trapezoidal shape that becomes narrower in width as it goes from the cover support groove (156) toward the rack support groove (134).

[0271] Both sides of the rack support groove (134) are in close contact with and supported by the support member (151), and the inner side of the rack support groove (134) may be spaced apart from the end of the support member (151).

[0272] A coating layer formed of a low-friction material, such as fluoropolymer or ceramic, may be provided on the rack support groove (134) or the support member (151) to minimize friction.

[0273] The rack support groove (134) may be filled with grease to minimize friction with the support member (151).

[0274] The housing cover (154) can be fixed to the rack housing (160) by a fastening member (159).

[0275] A sealing member (158) that prevents moisture or dust from entering from the outside may be applied to the end of the housing cover (154) and the outer surface of the rack housing (160).

[0276] Since these support members (151) and housing covers (154) are required to have a certain degree of rigidity and elasticity, they may be formed from one or more materials selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), phenol formaldehyde (PF), etc.

[0277] As described above, a steer-by-wire steering device according to some embodiments of the present disclosure may have a plurality of motors and may provide steering force to a rack bar. In addition, a steer-by-wire steering device according to some embodiments of the present disclosure may be provided with means to prevent rotation of the rack bar and may prevent unnecessary rotation of the rack bar even if a pinion is excluded.

[0278] Below, various embodiments of the method for calculating the rack bar position in such a steer-by-wire steering system are described. The method for calculating the rack bar position described below can be applied regardless of the position and shape of the motor described above. Alternatively, the method for calculating the rack bar position may be applied to the specific position and shape of the motor described above. Furthermore, the method for calculating the rack bar position may be applied regardless of the presence or absence of a rotation-prevention member, or it may be applied in combination with a specific rotation-prevention member.

[0279] In a steer-by-wire steering system, the electronic control unit (110) can control the operation 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 associated with the vehicle and control one or more drive motors based on the information or signals received from one or more sensors.

[0280] The aforementioned one or more sensors include various sensors configured in the vehicle necessary for steering, such as a steering angle sensor, a steering torque sensor, a vehicle speed sensor, and a rack position sensor. However, as described above, a pinion may not exist when the rack bar is configured to move by the first motor and the second motor. In this case, a rack position sensor for sensing the absolute position of the rack bar may not exist. Alternatively, a rack position sensor for sensing the absolute position of the rack bar may be installed on the gearbox connecting the first motor, the second motor, and the rack bar.

[0281] First, various embodiments for verifying the absolute position (or absolute angle) of a rack bar are described. Subsequently, embodiments using an absolute angle sensor to sense the absolute position (or absolute angle) of the rack bar are described.

[0282] The electronic control unit (110) may control the operation of the steering shaft motor (120). The electronic control unit (110) may be composed of a single physically integrated chip. Alternatively, the electronic control unit (110) may be composed of two or more chips. If it is composed of two or more chips, it may be divided into a reaction motor, a driving motor, a main control unit, etc., and may perform the aforementioned operations.

[0283] Meanwhile, the electronic control unit (110) can control the operation of a plurality of drive motors (e.g., 145, 147) to control the direction of travel of the vehicle according to the driver's steering intention.

[0284] A steer-by-wire steering system may be provided with a plurality of electronic control units (110), which is intended to ensure redundancy and continuously or stably perform the same operation even if any one of the plurality of electronic control units (110) is abnormal or inoperable. Alternatively, the plurality of electronic control units (110) may include a main electronic control unit and a sub electronic control unit. When the main electronic control unit is in a normal state, the main electronic control unit can control the operation of the steer-by-wire steering system, and when the main electronic control unit is abnormal or inoperable, the sub electronic control unit can control the operation of the steer-by-wire steering system.

[0285] The electronic control unit (110) can receive various information and control the steering of the vehicle. In the case of controlling the rack bar using two motors in the aforementioned steer-by-wire (SBW) system, accurate steering control is possible only if the position information of the rack bar is accurately recognized.

[0286] To this end, the electronic control unit (110) can receive position information of the rack bar from the rack position sensor. Alternatively, if there is no rack position sensor, the electronic control unit (110) may directly estimate the position information of the rack bar using two motor position information.

[0287] For example, the electronic control unit (110) can receive rotation information of each motor from two motor position sensors. The rotation information of each motor may include rotation information of the first motor and rotation information of the second motor. The rotation information of the first motor may be received from a motor position sensor configured in the first motor. The rotation information of the second motor may be received from a motor position sensor configured in the second motor.

[0288] The motor position sensor can sense rotation information of each motor. The motor position sensor can detect the rotation of the motor shaft. Alternatively, the motor position sensor may detect the rotation of any rotating member connected to the motor shaft. The motor position sensor can sense rotation information between 0 and 360 degrees for the rotation of each motor. The motor position sensor can measure the rotation angle and position of the motor.

[0289] The motor position sensor may be an optical encoder sensor that detects position by illuminating a disk with light. Alternatively, the motor position sensor may be a magnetic encoder sensor that measures the rotor's position using a magnetic sensor. Or, the motor position sensor may be an incremental encoder sensor that measures relative position changes by outputting a constant pulse. Or, the motor position sensor may be an absolute encoder sensor that measures absolute position by outputting a unique value for a specific location. Such motor position sensors can provide precise position and speed information.

[0291] Meanwhile, a Hall sensor that measures position by detecting changes in magnetic flux of a rotor to which a permanent magnet is attached may also be used as a motor position sensor. Used in BLDC motors, a motor position sensor may be configured by arranging three Hall sensors with a phase difference of 120 degrees or 60 degrees. In addition, there are resolvers that measure position in an analog manner using voltage changes, and inductive position sensors that sense position using the principle of electromagnetic induction. The motor position sensor in this specification may utilize the various types of sensors described above.

[0292] As explained above, motor position sensors can measure absolute angle values ​​based on a specific position of the motor. Alternatively, motor position sensors can sense a relative position indicating how much the motor has moved from a reference position. Furthermore, motor position sensors can measure the electrical position of the rotor in BLDC and PMSM motors. However, motor position sensors differ in terms of price and size, as well as in terms of measurement values ​​and precision.

[0293] When measuring a single rotation angle to measure a rotation angle between 0 and 360 degrees, position detection is possible only during a single rotation. In this case, it is difficult to verify the absolute position because it is reset when rotating beyond one full revolution. Although motor position sensors capable of measuring multiple rotation angles exist, they require the use of absolute sensors and have the disadvantages of a complex structure and high cost.

[0294] The present disclosure provides a method for obtaining absolute position information of a rack bar using two motor position information when each motor position sensor measures a relative position.

[0295] For example, two motors may be controlled to move the same rack bar but have different rotational speeds. In this case, the rotational information from the motor position sensors of the two motors may continuously change between 0 degrees and 360 degrees. If it is not an absolute angle sensor, this is not recorded or stored, and the rotational information sensed by the motor position sensor of the first motor may be one of the values ​​between 0 degrees and 360 degrees. Similarly, the rotational information sensed by the motor position sensor of the second motor may also be one of the values ​​between 0 degrees and 360 degrees.

[0296] The electronic control unit (110) can monitor rotation information of the first motor and rotation information of the second motor. The electronic control unit (110) estimates the absolute position of the rack bar using motor rotation information (motor position) generated from the two motors.

[0297] As explained above, the first motor and the second motor are connected to a single ball nut at different rotational speeds to move the rack bar. Therefore, even though the first and second motors rotate at different speeds, the ball nut must be rotated at the same speed. To achieve this, the motor pulley of the first motor and the motor pulley of the second motor may be configured with different gear ratios.

[0298] For example, the gear ratio may refer to, for example, but is not limited to, the ratio of the number of threads or diameters of the pulleys. For example, the gear ratio may be the ratio between the number of threads or diameter of the motor pulley connected to the motor shaft of the first motor and the number of threads or diameter of the motor pulley connected to the motor shaft of the second motor. There may be a significant difference in the gear ratio if the diameters of the motor pulleys are different.

[0299] In this structure, the first motor and the second motor rotate at different rotational speeds, and the electronic control unit (110) can receive different motor rotation information from the position sensors of the two motors.

[0300] The electronic control unit (110) can calculate the absolute position of the rack bar using preset information and motor rotation information of each motor.

[0301] For example, the difference in rotational speed between two motors can vary depending on the absolute position of the rack bar.

[0302] For example, the electronic control unit (110) can calculate the absolute position of the rack bar by monitoring the absolute angle change of the rotation information of each motor. For example, the electronic control unit (110) can determine the position of the rack bar using Equation 1.

[0303] [Mathematical Formula 1]

[0304]

[0305] R represents the moving position of the rack bar, θ represents the phase difference between the first rotation information of the first motor and the second rotation information of the second motor, K represents the distance the rack bar has moved while the phase difference between the first rotation information and the second rotation information changes from 0 to 0 the next time the phase difference becomes 0 when the rack bar moves in one direction, and n represents the number of times the phase difference becomes 0 while the rack bar moves in one direction.

[0306] That is, the electronic control unit (110) can continuously monitor the phase difference between the first rotation information of the first motor and the second rotation information of the second motor and record the number of times the phase difference becomes zero, thereby cumulatively confirming the position of the rack bar.

[0307] As another example, the electronic control unit (110) can determine the position of the rack bar based on a preset reference value. The rack bar has a structurally limited range of movement. Therefore, taking into account that the rack bar cannot move infinitely, the position of the rack bar can be predicted in advance based on the values ​​of first rotation information and second rotation information. The first rotation information and second rotation information based on the predicted position of the rack bar can be stored in advance in the electronic control unit (110) in a table or other data storage form.

[0308] When the electronic control unit (110) receives rotation information of the motor, it can directly estimate the absolute position of the rack bar by comparing it with previously stored data. However, in this case, the first rotation information and the second rotation information must be designed to have different values ​​across the entire stroke range of the rack bar. Therefore, the difference in gear ratio between the first motor and the second motor must be set so that the first rotation information and the second rotation information do not overlap at two or more absolute positions of the rack bar.

[0309] For example, the electronic control unit (110) can estimate the absolute position of the rack bar using the following mathematical formula 2.

[0310] [Mathematical Formula 2]

[0311] A = {(1st rotation information + m) × 1st gear ratio}

[0312] B = {(2nd rotation information + m) × 2nd gear ratio}

[0313] Rack bar position R = the intersection of A and B.

[0314] m is a natural number greater than or equal to 1 and less than or equal to the maximum travel distance of the rack bar.

[0315] FIG. 19 is a diagram illustrating a method for estimating a rack stroke range based on the difference between first rotation information and second rotation information. Referring to FIG. 19, first rotation information and second rotation information are shown in a Rack displacement (mm) situation from 0 to 75 using two motor rotation information (motor angles). As described above, the first gear ratio and the second gear ratio can be adjusted so that there is no overlap between the first rotation information and the second rotation information in the corresponding Rack displacement value.

[0316] Now, referring to FIG. 20, a steer-by-wire system (10) used in a vehicle (1) according to an exemplary embodiment is illustrated. In conventional automotive steering systems, such as electric power steering (EPS) systems, the steering wheel is mechanically connected 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 eliminates this mechanical connection and instead electronically controls the steering angle of the road wheels (30) based on measurements from the steering wheel or hand wheel (20) and / or one or more control signals from a controller (50), and uses a plurality of actuators, such as electric motors, to provide feedback to the driver or operator of the vehicle (1). Additionally, in the steer-by-wire system (10), the steering angle of the road wheel (30) may be controlled by one or more control signals generated by a controller (50) based on one or more control signals generated by an autonomous driving system or an advanced driver assistance system (ADAS) and / or data from one or more sensors.

[0317] A steer-by-wire system (10) allows 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) through the operation of the steering wheel (20). The steering wheel (20) is operably or mechanically coupled or fixed to a steering shaft (or steering column) (22). The steering wheel (20) may be connected directly or indirectly to the steering shaft (22). For example, the steering wheel (20) may be connected to the steering shaft (22) via a gear, shaft, belt and / or any connecting means. Alternatively, the steering wheel (20) may be fixed to the steering shaft (22). The steering shaft (22) may rotate together with the steering wheel (20).

[0318] One or more steering wheel sensors (40) may be configured to detect the position, angular displacement, or movement (25) of the steering shaft (22) or steering wheel (20), and to detect the torque of the angular displacement or movement (25) of the steering shaft (22) or steering wheel (20). The steering wheel sensors (40) provide an electrical signal to the controller (50) indicating the angular displacement and / or torque (25). The controller (50) transmits and / or receives a signal to and from the upper actuator (27) to actuate the upper actuator (27) (e.g., a steering feedback actuator having an electric motor) 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) in response to the control signals received from the controller (50) to provide feedback to the driver or operator (similar to the feedback provided by the wheels in a manually steering vehicle).

[0319] In a steer-by-wire system (10), the steering wheel (20) can be mechanically separated from the road wheel (30). Therefore, the steer-by-wire steering system (10) must provide the same "road feel" to the driver or operator through a direct mechanical connection as the driver receives. Additionally, it is desirable to have a device that provides a mechanical backup "road feel" in the event of multiple electronic failures in the steer-by-wire system. Furthermore, a device that provides a good on-center feel and accurate torque change when the steering wheel is rotated is also desirable. Accordingly, the vehicle (1) may include an upper actuator (27) (e.g., a steering feedback actuator).

[0320] The upper actuator (27) may include, for example, but is not limited to, an electric motor connected to a steering shaft or steering column (22). For example, a gear or belt assembly may connect the output of the upper actuator (27) to the steering shaft (22). Alternatively, the upper actuator (27) may be directly coupled to the steering shaft (22) or the hand wheel (20). The upper actuator (27) may be operated to provide resistance to the rotation of the steering wheel (20). A 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 each rotation (25) of the steering wheel (20). In response to a signal from the sensors (40), the controller (50) generates and transmits a signal corresponding to the detected torque and each rotation of the steering wheel (20) detected by the sensors (40), and the upper actuator (27) generates a resistance torque to the rotation of the steering wheel (20) in response to the signal from the controller (50) to provide a steering sensation to the driver.

[0321] 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 the steering rack (36) in response to control signals received from the controller (50). For example, the lower actuator (32) generates rotational movement in response to control signals from the controller (50), and the rotational movement of the lower actuator (32) is converted into linear movement of the steering rack (36). Tie rods and knuckles (37) connect the steering rack (36) to a road wheel or vehicle wheel (30) and convert the linear movement of the steering rack (36) into rotation of the road wheel (30).

[0322] When in use, the steering wheel (20) is angularly displaced (25), and the steering shaft (22) can also be angularly displaced. A sensor (40) detects the angular displacement and torque (25) of the steering shaft (22) connected to the steering wheel (20), and the sensor (40) transmits signals indicating the relative amount of the angular displacement and torque (25) of the steering shaft (22) to a controller (50). The controller (50) transmits control signals indicating the relative amount of angular displacement and / or torque of the steering shaft (22) to a lower actuator (32). In response, the lower actuator (32) moves the steering rack (36) to rotate the road wheel (30). Thus, the controller (50) controls the distance the steering rack (36) moves based on the amount of angular displacement (25) of the steering wheel (20). The movement of the steering rack (36) changes the position of the road wheels (30) of the vehicle (1) by operating the tie rods and knuckles (37). Thus, when the steering wheel (20) is rotated, the road wheels (30) are controlled to rotate.

[0323] To perform specified functions and desired processing as well as corresponding calculations (e.g., identification of motor parameters, control algorithm(s), etc.), the controller (50) may include processor(s), computer(s), DSP(s), memory, storage device, register(s), timing, interrupt(s), communication interface(s), and input / output signal interfaces, etc., and may include combinations including at least one of these, but is not limited thereto. For example, the controller (50) may include input signal processing and filtering that enables accurate sampling and conversion or acquisition of these signals from the communication interface. Although FIG. 20 illustrates the controller (50) as a single controller, a person skilled in the art will understand that the controller (50) may be distributed among a number of vehicle controllers, such as the first circuit (320) of the first power pack (300) and the second circuit (420) of the second power pack (400).

[0324] FIG. 21 is a perspective view for showing a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 22 is a cross-sectional view for explaining a steer-by-wire system according to an exemplary embodiment of the present disclosure. FIG. 23 is a partial cross-sectional view for explaining a steer-by-wire system according to an exemplary embodiment of the present disclosure.

[0325] The lower actuator (32) (e.g., a road wheel actuator) may include a first power pack (300) and a second power pack (400).

[0326] The first power pack (300) may include a first motor (310) having a first motor shaft (311), a first circuit (320), and a first sealing bearing (330). The second power pack (400) may include a second motor (410) having a second motor shaft (411), a second circuit (420), and a second sealing bearing (430).

[0327] The first and second circuits (320 and 420) may include any suitable circuits and electronic components, such as a microprocessor, processor, computer and / or memory, mounted thereon. The first and second circuits (320 and 420) may be configured, for example, to supply power to the first and second motors (310 and 320), to enable or disable the operation of the first and second motors (310 and 320), and to change the speed and / or rotational direction of the first and second motors (310 and 320), but are not limited thereto.

[0328] The first or second sealing 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 rotate smoothly by being rotatably supported by the first or second sealing bearing (330 or 430). The first or second sealing bearing (330 or 430) may have one or more sealing shields or protective barriers mounted on the sides of the bearing to protect against external contamination such as dust, sand, and water. For example, the first or second sealing bearing (330 and 430) may be located around a hole in the first or second power pack housing (350 or 450) through which the first or second motor shaft (311 or 411) passes, so that the first or second sealing bearing (330 or 430) can prevent external contaminants such as dust, moisture and debris from entering the first or second power pack housing (350 or 450). The first or second sealing bearing (330 or 430) can prevent a common point of intrusion of external contaminants from inside the gear cavity into the first or second power pack (300 or 400). Because the first or second sealing bearing (330 or 430) has an integral shield inside, less space is required in the first or second power pack (300 or 400), and production efficiency can be improved.

[0329] The first drive pulley (360) may be provided on the first motor shaft (311). For example, the first drive pulley (360) may be formed directly on the first motor shaft (311) or attached to the first motor shaft (311). The first drive pulley (360) may have an outer surface that engages with the inner surface of the first drive belt (370). The first drive pulley (360) of the first power pack (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 power pack (300) to a driven pulley (520) of the rotary-to-linear conversion mechanism (500). The first motor (310) can provide rotational torque to the first drive pulley (360) through the first motor shaft (311). The rotational force of the first drive pulley (360) is transmitted to the first drive belt (370). As rotational force is applied to the first drive belt (370), the rotational force of the first motor (310) of the first power pack (300) is transmitted to the rotation-linear conversion mechanism (500).

[0330] A second drive pulley (460) may be provided on a second motor shaft (411). For example, the second drive pulley (460) may be formed directly on the second motor shaft (411) or attached to the second motor shaft (411). The second drive pulley (460) may have an outer surface that engages with the inner surface of the second drive belt (470). The second drive pulley (460) of the second power pack (400) is rotatably connected to a rotary-linear conversion mechanism (500) via the second drive belt (470). For example, the second drive belt (470) operably connects the second drive pulley (460) of the second power pack (400) to a driven pulley (520) of the rotary-linear conversion mechanism (500). The second motor (410) may provide rotational torque to the second drive pulley (460) via the second motor shaft (411). The rotational force of the second drive pulley (460) is transmitted to the second drive belt (470). As the rotational force is applied to the second drive belt (470), the rotational force of the second motor (410) of the second power pack (400) is transmitted to the rotation-linear conversion mechanism (500).

[0331] The above rotary-linear conversion mechanism (500) (e.g., nut-screw mechanism and ball nut-screw mechanism) may be configured to convert 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 linear motion to move the steering rack (36) linearly. The rotary-linear conversion mechanism (500) may include a rotatable part (510). For example, the rotatable part (510) may include a nut or a ball nut, but may not be necessary. At least a portion of the steering rack (36) is retained inside or surrounded by the rotatable part (510). The rotatable part (510) has a track groove (521) with internal threads, and at least a portion of the steering rack (32) has a track groove (615) with external threads for a rotational arrangement of rotating bodies (522) (e.g., balls). Rotating bodies (522) are positioned between a threaded track groove (521) inside the rotatable part (510) and a threaded track groove (615) outside the steering rack (36). The rotating bodies (522) may be metal spheres and reduce friction and transfer load between adjacent parts. The rotatable part (510) is rotatably supported by the steering rack (36) through the rotating bodies (522) and the bearing assembly (540). However, in other embodiments of the present disclosure, the threaded track groove (521) inside the rotatable part (510) and the threaded track groove (615) outside the steering rack (36) may engage directly with each other without the rotating bodies (522).

[0332] One or more bearings (540) may support the rotational movement of the rotatable part (510) of the rotation-linear conversion mechanism (500) (e.g., ball nut or nut) by supporting the rotatable part (510). For example, the first bearing (540-1) supports one side of the rotatable part (510), and the second bearing (540-2) supports the other side of the rotatable part (510). The bearing (540) may be, for example, a single row deep groove bearing, but is not limited thereto. The bearing (540) may be located between the rotation-linear conversion mechanism (500) and a non-rotating structure (e.g., but not limited to, the first gear housing (380) or the second gear housing (480)). A bearing (540) is used to rotatably support a rotatable part (510) for rotating relative to a non-rotating structure.

[0333] A first drive belt (370) operably coupled to the first motor (310) of the first power pack (300) is rotatably coupled to one part of the driven pulley (520), and a second drive belt (470) operably coupled to the second motor (410) of the second power pack (400) is rotatably coupled to another part of the driven pulley (520). The outer diameter of one part of the driven pulley (520) to which the first drive belt (370) is coupled and the outer diameter of the other part of the driven pulley (520) to which the second drive belt (470) is coupled may be the same. However, if necessary to identify the linear position of the steering rack (36) using a vernier algorithm, the outer diameter of one part of the driven pulley (520) to which the first drive belt (370) is coupled may be different from the outer diameter of the other part of the driven pulley (520) to which the second drive belt (470) is coupled. Additionally, the number of teeth of one part of the driven pulley (520), which is provided to the rotatable part (510) of the rotary-linear conversion mechanism (500) and operably coupled to the first motor (310) of the first power pack (300), and the number of teeth of the other part of the driven pulley (520), which is provided to the rotatable part (510) of the rotary-linear conversion mechanism (500) and operably coupled to the second motor (410) of the second power pack (400), are the same as each other. However, if necessary to identify the linear position of the steering rack (36) using a vernier algorithm, the number of teeth of one part of the driven pulley (520), which is provided to the rotatable part (510) of the rotary-linear conversion mechanism (500) and operably coupled to the first motor (310) of the first power pack (300), may differ from the number of teeth of another part of the driven pulley (520), which is provided to the rotatable part (510) of the rotary-linear conversion mechanism (500) and operably coupled to the second motor (410) of the second power pack (400).

[0334] A flange protruding from the outer surface of the driven pulley (520) of the rotary-linear conversion mechanism (500) may be positioned between the first drive belt (370) and the second drive belt (470), and accordingly, the first drive belt (370) and the second drive belt (470) are positioned spaced apart from each other to keep them in place and prevent interference with each other.

[0335] Both the first drive pulley (360) of the first power pack (300) and the second drive pulley (460) of the second power pack (400) are rotatably connected to one driven pulley (520) of the rotary-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) is such that the inner engagement surfaces of the belts (370 and 470) wrap around and engage with both the first and second drive pulleys (360 and 460) of the first and second power packs (300 and 400) and the driven pulley (520) fixed to the rotatable part (510) of the rotary-linear conversion mechanism (500). At least one of the first drive pulley (360) of the first power pack (300) and the second drive pulley (460) of the second power pack (400) causes rotation of the driven pulley (520) and the rotatable part (510) of the rotation-linear conversion mechanism (500), and then the rotation of the rotatable part (510) of the rotation-linear conversion mechanism (500) is converted into linear motion of the steering rack (36) by the rotation-linear conversion mechanism (500).

[0336] The first motor position sensor (390) responds to the rotation of the first motor shaft (311). The first motor position sensor (390) may be positioned to be in a sensing relationship with the first motor shaft (311). For example, the first motor position sensor (390) may be located adjacent to or around the first motor shaft (311). The first motor position sensor (390) may detect or sense each position of the first motor (310) (e.g., each position of the first drive pulley (360) or each position of the first motor shaft (311)) in a single-rotation range of 0 to 360 degrees (0-360°). The first motor position sensor (390) may generate output signals indicating the sensed each position of the first motor shaft (311). The first motor position sensor (390) is electrically connected to the first circuit board (320).

[0337] The second motor position sensor (490) responds to the rotation of the second motor shaft (411). The second motor position sensor (490) may be positioned to be in a sensing relationship with the second motor shaft (411). For example, the second motor position sensor (490) may be located adjacent to or around the second motor shaft (411). The second motor position sensor (490) may detect or sense each position of the second motor (410) (e.g., each position of the second drive pulley (460) or each position of the second motor shaft (411)) in a single-rotation range of 0 to 360 degrees (0-360°). The second motor position sensor (490) may generate output signals indicating the sensed each position of the second motor shaft (411). The second motor position sensor (490) is electrically connected to the second circuit board (420).

[0338] The first motor position sensor (390) and the second motor position sensor (490) may each be any suitable device(s) for generating a signal that responds to the rotation of the first motor shaft (311) and the second motor shaft (411). For example, the first and second motor position sensors (390 and 490) may be inductive sensors, magnetic sensors (e.g., Hall effect sensors), magnetoresistive (MR) sensors, or any other sensor known in the relevant art field having a similar function.

[0339] An induction sensor may be a sensor configured to operate based on the principle of electromagnetic induction to detect or measure adjacent metal objects. An inductor generates a magnetic field when current flows through it. Conversely, when the magnetic field through it changes, current flows through a circuit containing the inductor. This effect can be used to detect metal objects interacting with a magnetic field. For example, an induction sensor according to an embodiment of the present disclosure may utilize the embodiments described in U.S. Patent Application Serial No. 18 / 930,897 titled “Inducive Sensor System Comprising Inducive Torque and Position Sensor Assemblies,” the entirety of which is incorporated herein by reference. In an embodiment for an inductive sensor, an excitation or transmitter coil set configured to generate an electromagnetic field for a first or second motor shaft (311 or 411) or a first or second drive pulley (360 or 460), and a receiver coil set configured to detect an electromagnetic field around the first or second motor shaft (311 or 411) may be included in or mounted thereon on a first or second circuit board (320 or 420), and a target having a metal pattern or one or more conductive loops configured to influence the electromagnetic field generated by the said excitation or transmitter coil set may be included in or attached thereon to the first or second motor shaft (311 or 411) or the first or second drive pulley (360 or 460). The inductive sensor can reduce the size of the first and second power packs (300 and 400) and lower the manufacturing cost of the steer-by-wire system (10).

[0340] In an embodiment for a magnetic sensor (e.g., a Hall effect sensor), the first or second motor shaft (311 or 411) or the first or second drive pulley (360 or 460) may have a magnetic gradient formed on the surface of the first or second motor shaft (311 or 411) or the first or second drive pulley (360 or 460) defined by a plurality of alternating north and south magnetically charged elements spaced circumferentially around the circumference of the first or second motor shaft (311 or 411) or the first or second drive pulley (360 or 460). A magnetic sensor configured to detect or sense a magnetic field around a first or second motor shaft (311 or 411) or a first or second drive pulley (360 or 460) may be included in or mounted thereon on a first or second circuit board (320 or 420).

[0341] A processor included in at least one of the controller (50), the first circuit (320), the second circuit (420), or the electronic control unit of the vehicle (1) may be configured to identify the linear position of the steering rack (36) based on the position of the first motor (310) detected by the first motor position sensor (390) and the position of the second motor (410) detected by the second motor position sensor (490). For example, a vernier algorithm may be used to determine the linear position of the steering rack (36) based on the position of the first motor (310) and the position of the second motor (410). The rotation ratio associated with the first motor (310) and the rotation ratio associated with the second motor (410) may be different from each other. For example, the rotation ratio may be a ratio of the number of rotations or angular velocities of the motors. In an exemplary embodiment, the number of teeth of the first drive pulley (360) provided on the first motor shaft (311) of the first motor (310) of the first power pack (300) and the number of teeth of the second drive pulley (460) provided on the second motor shaft (411) of the second motor (410) of the second power pack (400) are different from each other, and accordingly, the rotation ratio associated with the first motor (310) and the rotation ratio associated with the second motor (410) are different from each other. In another exemplary embodiment, the outer diameter of the first drive pulley (360) provided on the first motor shaft (311) of the first motor (310) of the first power pack (300) may be different from the outer diameter of the second drive pulley (460) provided on the second motor shaft (411) of the second motor (410) of the second power pack (400). The above-described vernier algorithm can calculate values ​​using two related variables having different phases or periods. Because the rotation ratio of the first motor (310) and the second motor (410) is different, the processor can identify the linear position of the steering rack (36) by using the phase difference between the position of the first motor (310) detected by the first motor position sensor (390) and the position of the second motor (410) detected by the second motor position sensor (490), which has a different period.By using a vernier algorithm based on different rotation ratios caused by the configuration of the first drive pulley (360), the second drive pulley (460), and the driven pulley (520) in relation to the position of the steering rack (36) and / or the movement of the steering rack (36), the position of the steering rack (36) can be determined without a learning algorithm, an electronic rotation counter, or a linear position sensor for detecting the linear position of the steering rack (36).

[0342] One or more rack supports (550) may be configured to support the steering rack (36). The rack supports (550) may limit the rotation of the steering rack (36) to prevent the steering rack (36) from rotating relative to a non-rotating structure (e.g., but not limited to, a rack housing (560)). For example, to prevent rotation of the steering rack (36), the rack supports (550) may include a preloaded roller or a rotatable rack shoe, and the steering rack (36) may have a generally flat or slightly curved surface or a shape corresponding to the shape of the rack supports (550) so that it can slide relative to the rack housing (560) without rotating. A cross-section of a portion of the steering rack (36) may be generally D-shaped and may have a flat or slightly curved surface to be operablely associated with the rack supports (550). Alternatively, the steering rack (36) has a groove (or protrusion) that engages with a key and a protrusion (or groove) of the rack support (550) to limit the rotational movement of the steering rack (36).

[0343] The rack support (550) can limit the linear range of movement of the steering rack (36). The rack support (550) can provide a stop position that limits the movement of the steering rack (36) (e.g., the linear range of movement of the steering rack (36)), thereby preventing the steering rack (36) from exceeding the linear range of movement by limiting the linear movement of the steering rack (36).

[0344] For example, one rack support (550) may be placed on one side of the rack housing (560), and another rack support (550) may be placed on the other side of the rack housing (560).

[0345] The first gear housing (380) has an internal space for accommodating a first drive pulley (360), a first drive belt (370), and a portion of the driven pulley (520) of the rotary-linear conversion mechanism (500). The second gear housing (480) has an internal space for accommodating a second drive pulley (460), a second drive belt (470), and a portion of the driven pulley (520) of the rotary-linear conversion mechanism (500). The first gear housing (380) may further include a first bearing (540-1), and the second gear housing (480) may further include a second bearing (540-2). The first gear housing (380) and the second gear housing (480) may be formed as separate parts and joined together.

[0346] The shape of the first gear housing (380) and the shape of the second gear housing (480) may be symmetrical to each other. The first gear housing (380) and the second gear housing (480) are joined to each other in the central portion of the rack housing (560). The first motor shaft (311) of the first motor (310) of the first power pack (300) and the second motor shaft (411) of the second motor (410) of the second power pack (400) may be arranged coaxially with each other. The first drive belt (370) and the second drive belt (470) are arranged parallel to each other and are joined to the common driven pulley (520) of the rotation-linear conversion mechanism (500).

[0347] The first gear housing (380) and the second gear housing (480) of this configuration can reduce the complexity of the parts and make the assembly and production of the steer-by-wire system (10) easier.

[0348] Now, referring to FIG. 24, FIG. 24 is a data flow diagram illustrating power packs (i.e., a first power pack (300) and a second power pack (400)) of a steer-by-wire system of FIG. 1 through 23 according to an exemplary embodiment of the present disclosure. In particular, additional components and operations of the first power pack (300) and the second power pack (400) will be described in more detail with reference to FIG. 24.

[0349] As illustrated in FIG. 24, the first power pack (300) includes (i.e., in addition to the components already discussed above with reference to FIG. 21 through 23) a first power pack motor position sensor (2402) (i.e., the first motor position sensor (390) of FIG. 23), a time generator circuit (2404), and a first circuit (320) (also referred to herein as the “first controller”).

[0350] As discussed above with reference to FIG. 23, the first power pack motor position sensor (2402) can detect or sense the angular position of the first motor (310) (e.g., the angular position of the first drive pulley (360) or the angular position of the first motor shaft (311)) within a single-turn range of 0 to 360 degrees (0-360°), and can generate output signals indicating the sensed angular position of the first motor shaft (311) while electrically connected to the first circuit board (320).

[0351] The time generator circuit (2404) may be configured as part of the first circuit (320) or may be a separate circuit having its own processor and memory (e.g., a microcontroller, a microchip, a combination of electronic devices forming the circuit, etc.). The time generator circuit (2404) may be configured to generate timestamps for output signals generated by the first power pack motor position sensor (2402). For example, whenever the first power pack motor position sensor (2402) reads (i.e., detects) and outputs the angular position of the first motor (310) (also referred to herein as the "first power pack motor position" of the first motor (310)), the time generator circuit (2404) may provide a timestamp to be associated (i.e., added) with each of these readings. The above timestamp may include a date and time of any format and precision (e.g., in nanoseconds or at a similar level) without departing from the scope of the embodiments disclosed herein.

[0352] In particular, as a non-limiting example, the operations of the time generator circuit (2404) and the first power pack motor position sensor (2402) may be synchronized so that the time generator circuit (2404) recognizes whenever the first power pack motor position sensor (2402) performs a reading and generates a timestamp at each reading point. Other methods and techniques for associating sensor measurements with timestamps may also be applied to the operations of the time generator circuit (2404) and the first power pack motor position sensor (2402) without departing from the scope of the embodiments disclosed herein.

[0353] In the embodiments, the time generator circuit (2404) is provided in only one of the first circuit (320) or the second circuit (420) (also referred to herein as the “second controller”) (i.e., the time generator circuit is the only motor position timestamp generating component between the first and second power packs (300, 400) of the steer-by-wire system). In other words, the steer-by-wire system of FIGS. 21 through 23 is provided with only a single (i.e., one) time generator circuit (2404). Consequently, the power pack among the first and second power packs (300, 400) that lacks the time generator circuit (2404) will not be aware of when its respective motor position sensor (i.e., 2402 or 2432) performs a measurement. In other words, the motor position timing (i.e., timestamp) generated by the time generator circuit (2404) of the first power pack (300) (i.e., in the exemplary configuration shown in FIG. 24) will be the sole source of motor position timing information available to and used by the second power pack (400).

[0354] Additionally, in the embodiments, at least some first operations of the first power pack and at least some second operations of the second power pack are not time-synchronized. For example, the first power pack motor position sensor (2402) and the second power pack motor position sensor (i.e., the second motor position sensor (490) of FIG. 23) are not synchronized with each other to perform measurements at exactly the same time. Consequently, the motor position timing (i.e., timestamp) generated by the time generator circuit (2404) of the first power pack (300) (i.e., in the exemplary configuration shown in FIG. 24) will be used as the sole timing information to synchronize the first operations of the first power pack (300) and the second operations of the second power pack (400) that are not synchronized.

[0355] In the embodiments, and as illustrated in FIG. 24, the first circuit (320) may include a first power pack data transmitter (2406), a first power pack data receiver (2408), and a first power pack other process circuit (2410). The first power pack data transmitter (2406) may be configured as part of the processor of the first circuit (320). The first power pack data transmitter (2406) may be configured to process first power pack related data (e.g., the first power pack motor position of the first motor (310), timestamps generated by the time generator circuit (2404), etc.) and to transmit such first power pack related data to the second power pack (400) (i.e., the second circuit (420) of the second power pack (400)) through a communication interface (2499).

[0356] For example, the first power pack data transmitter (2406) may be configured to (i) obtain a first combined motor position reading including a timestamp for the first power pack (300) by combining the first power pack motor position of the first motor (310) measured (i.e., detected) by the first power pack motor position sensor (2402) and each motor position timing (i.e., timestamp) generated by the time generator circuit (2404) for the corresponding measurement (received by the first circuit (320); and (ii) transmit (i.e., provide) the first combined motor position reading including a timestamp for the first power pack (300) to the second circuit (420) (i.e., the second power pack data receiver (2436) of the second circuit (420), which will be discussed in more detail below) via the communication interface (2499).

[0357] In the embodiments, the first power pack data receiver (2408) may be configured to receive data (e.g., data related to the second power pack, etc.) from the second power pack (400). Additionally, the first power pack other process circuit (2410) may be configured to perform one or more processes to manage the operation of the first power pack (300) using the data received by the first circuit (320) (e.g., data related to the first power pack, data related to the second power pack, data from other ECUs discussed above in FIGS. 1 to 23, etc.).

[0358] For example, the first power pack other process circuit (2410) may be configured to use the received data to calculate a first pinion angle value for a steer-by-wire system (i.e., a linear position of the steering rack (36) calculated using a Vernier algorithm). As another example, the first power pack other process circuit (2410) may also be configured to use the received data to detect one or more mechanical defects (e.g., belt slip, belt skip, etc.) occurring within the first power pack (300). That is, said mechanical defects may be detected using methods disclosed in U.S. Patent Application No. 19 / 358,613 filed on October 15, 2025, the entire contents of said application incorporated herein by reference. Other processes and methods related to the operation of the first power pack (300) may also be performed by the first power pack other process circuit (2410) without departing from the scope of the embodiments disclosed herein.

[0359] In the embodiments, the communication interface (2499) between the first power pack (300) and the second power pack (400) may be configured as a Controller Area Network with Flexible Data-Rate CAN-FD communication interface / protocol. Alternatively, the communication interface (2499) may be configured using an Ethernet-based communication interface / protocol. Other types of physical and / or non-physical communication interfaces / protocols other than CAN-FD and Ethernet may also be used as the communication interface (2499) without departing from the scope of the embodiments disclosed herein. In the embodiments, the timestamp (i.e., motor position timing) generated by the time generator circuit (2404) may be based on the timestamp associated with the communication interface (2499). For example, assume that the communication interface (2499) is a CAN-FD communication interface / protocol, and that when the first power pack motor position sensor (2402) performs a measurement (or provides an output to the first circuit (320)), the interface displays (shows) the time of 4:10:36 PM ET on November 3, 2025. Then, the time generator circuit (2404) reads (i.e., detects) this time (4:10:36 PM ET on November 3, 2025) associated with the CAN-FD communication interface / protocol, and can use this time as a timestamp for the corresponding measurement / output.

[0360] Now, looking at the second power pack (400) as illustrated in FIG. 24 and discussed above, the second power pack (400) may have all the components of the first power pack already discussed, except for the time generator circuit (2404), which is limited to being provided to only one of the two power packs. In particular, the second power pack (400) may include a second power pack motor position sensor (2432) configured for the second power pack, which is configured identically to the first power pack motor position sensor (2402) but configured for the second power pack (i.e., the second motor position sensor (490) of FIG. 23). Additionally, the second circuit (420) may include a second power pack data receiver (2436) (identical to the first power pack data receiver (2408) but configured for the second power pack (400)), a second power pack data transmitter (2434) (identical to the first power pack data transmitter (2406) but configured for the second power pack (400)), and a second power pack other process circuit (2438) (identical to the first power pack other process circuit (2410) but configured for the second power pack (400)).

[0361] For example, a second power pack data receiver (2436) is configured to receive data from the first power pack (300) (and / or any other ECUs in the system of FIGS. 1 through 23). A second power pack data transmitter (2434) may be configured to transmit data (e.g., second power pack related data) to the first power pack (300) (and / or any other ECUs in the system of FIGS. 1 through 23). And finally, a second power pack other process circuit (2438) may be configured to use any received data to manage the operation of the second power pack (400) and / or the steer-by-wire system (e.g., to calculate a second pinion angle for the steer-by-wire system, or to determine one or more mechanical defects occurring within the second power pack (400), etc.).

[0362] In the embodiments, since the second power pack (400) is not equipped (i.e., configured) to generate its own timestamps (i.e., motor position timing and / or motor position timing information) for the second power pack motor positions generated by the second power pack motor position sensor (2432) for the second motor (410), the second power pack is configured to rely on the first power pack (300) for these timestamps. For example, and as will be discussed in more detail below with reference to FIG. 25, the second circuit (420) of the second power pack (400) (i.e., the second power pack data transmitter (2434) of the second circuit (420)) may be configured to obtain a second combined motor position reading including a timestamp for the second power pack (300) by combining the second power pack motor position of the second motor (410) measured (i.e., detected) by the second power pack motor position sensor (2432) and each motor position timing (i.e., timestamp) received from the first circuit (320) of the first power pack (300) (i.e., from the first power pack data transmitter (2406) of the first circuit (320). These second combined motor position readings containing timestamps (and the first combined motor position readings containing timestamps received from the first power pack (300)) may be used in processes and operations performed by the second power pack other process circuit (2438) to manage the operation of the second power pack (400) and / or the steer-by-wire system.

[0363] In the embodiments, the first power pack (300) and the second power pack (400) may be configured to have a master / slave (or master / follower) relationship. For example, as shown in FIG. 24, the first power pack (300) is configured to play the "master" role, while the second power pack (400) is configured to play the "follower" role. Consequently, at the start of the steer-by-wire system, the first power pack (300) will play the master role and the second power pack (400) will play the follower role. These master and follower roles of the two power packs may be changed during the operation of the steer-by-wire system. More specifically, at any point during the operation of the steer-by-wire system of FIG. 24, the first power pack (300) may be replaced to act as a follower and the second power pack (400) may be replaced to act as a master. In the embodiments, the power pack configured to act as a master will host the time generator circuit (2404).

[0364] Additionally, in the embodiments, each power pack (i.e., the first power pack (300) and the second power pack (400)) may host redundant circuits of their respective first circuit (320) and second circuit (420). That is, the first power pack (300) may have two first circuits (320), one of which may be a main controller and the other a backup (i.e., auxiliary) controller. Likewise, the second power pack (300) may have two second circuits (320), one of which may be a main controller and the other a backup (i.e., auxiliary) controller.

[0365] In such a configuration where each power pack includes two instances of its respective circuit (i.e., controller, ECU, etc.), the first power pack motor position may include motor positions measured by both of the two first circuits (320) (i.e., of the first motor (310)), and the second power pack motor position may include motor positions measured by both of the two second circuits (i.e., of the second motor (410)). Finally, a timestamp generated by the time generator circuit (2404) (e.g., timestamp A, to be discussed below with reference to FIG. 25) may also include timestamps of both motor positions (i.e., of the first motor (310)) measured by both of the two first circuits (320) (or two second circuits if the time generator circuit (2404) is hosted by the second power pack (400) instead of the first power pack (300)).

[0366] Now, referring to FIG. 25, FIG. 25 illustrates an implementation example according to an exemplary embodiment of the present disclosure (i.e., operations performed by the first and second power packs (300, 400)) (in the form of a data flow diagram). FIG. 25 includes numbers contained within circles. Each of these numbers is used to indicate a time point and may be presented in chronological order starting from the number "1" (but is not limited thereto). In the example of FIG. 25, it is assumed that the first power pack motor position sensor (2402) and the second power pack motor position sensor (2432) continuously provide motor position measurements to the first and second circuits (320, 420), respectively, at a predetermined interval (e.g., a predetermined interval set by the manufacturer).

[0367] Each of these numbers may describe an action in a flowchart related to actions performed by a steer-by-wire system (i.e., the first and second power packs (300, 400) of the steer-by-wire system). For example, the number "1" may correspond to the first action or the first set of actions (i.e., action 1) of a flowchart having multiple actions.

[0368] Starting from a first point in time (i.e., at the circular number "1" shown in FIG. 25), the first power pack motor position sensor (2402) measures the first power pack motor position of the first motor (310) (i.e., the PPK1 motor position shown in FIG. 25), and the time generator circuit (2404) generates a timestamp for this measurement by the first power pack motor position sensor (2402) (i.e., motor position timing; timestamp A shown in FIG. 25). Then, the PPK1 motor position and timestamp A are provided to the first circuit (320).

[0369] At a second point in time (i.e., at the circular number "2" shown in FIG. 25), the first power pack data transmitter (2406) of the first circuit (320) adds timestamp A to the PPK1 motor position (i.e., combines timestamp A with the PPK1 motor position) to obtain a first combined motor position reading (i.e., "PPK1 motor position + timestamp A" as shown in FIG. 25) containing a timestamp for the first power pack. Then, the first power pack data transmitter (2406) transmits the PPK1 motor position + timestamp A to the second power pack (400) (i.e., the second power pack data receiver (2436) of the second circuit (420) of the second power pack (400)).

[0370] At the third point in time (i.e., at the circular number "3" shown in FIG. 25), the second power pack data receiver (2436) receives the PPK1 motor position + timestamp A from the first power pack (300) and parses this data to obtain timestamp A. Then, timestamp A is provided by the second power pack data receiver (2436) to the second power pack data transmitter (2434).

[0371] At the fourth point in time (i.e., at the circular number "4" shown in FIG. 25), the second power pack data transmitter (2434) receives timestamp A from the second power pack data receiver (2436) and adds timestamp A to an instance of the second power pack motor position (i.e., the PPK2 motor position shown in FIG. 25) provided to the second circuit (420) by the second power pack motor position sensor (2432). In particular, timestamp A is added (i.e. combined) to the PPK2 motor position to obtain a second combined motor position reading (i.e., PPK2 motor position + timestamp A) containing a timestamp for the second power pack (400).

[0372] In the embodiments, the instance of the PPK2 motor position added to the timestamp A may be any one of the following: (i) an instance of the PPK2 motor position provided to (i.e. received) the second circuit (420) immediately before the timestamp A is received by the second power pack data transmitter (2434); (ii) an instance of the PPK2 motor position provided to (i.e. received) the second circuit (420) immediately after the timestamp A is received by the second power pack data transmitter (2434); or (iii) an instance of the PPK2 motor position provided to (i.e. received) the second circuit (420) simultaneously with the reception of the timestamp A by the second power pack data transmitter (2434).

[0373] When acquired, the PPK2 motor position + timestamp A is subsequently provided (i.e., transmitted) to the first power pack data receiver (2408) of the first circuit (320) of the first power pack (300) by the second power pack data transmitter (2434).

[0374] At the fifth point in time (i.e., at the circular number "5" shown in FIG. 25), the first power pack data receiver (2408) obtains the PPK2 motor position + timestamp A from the second power pack (400). Now, both power packs (i.e., the first and second power packs (300, 400)) have both the (PPK1 motor position + timestamp A) and (PPK2 motor position + timestamp A) data, and thus can advantageously "synchronize" their data with each other using the processes and operations performed by the first power pack other process circuit (2410) and the second power pack other process circuit (2438).

[0375] At the 6th point in time (i.e., at the circular number “6” shown in FIG. 25, and this may occur at any time for the first power pack other process circuit (2410) and the second power pack other process circuit (2438) when each power pack receives both the (PPK1 motor position + timestamp A) and (PPK2 motor position + timestamp A) data), the first power pack other process circuit (2410) and the second power pack other process circuit (2438) may each perform one or more processes and operations to manage the first power pack (300) and the second power pack (400) respectively using both the (PPK1 motor position + timestamp A) and (PPK2 motor position + timestamp A) data.

[0376] For example, assuming timestamp A is 4:10:36 PM ET on November 3, 2025, by using both the (PPK1 motor position + timestamp A) and (PPK2 motor position + timestamp A) data, each of the first power pack other process circuit (2410) and the second power pack other process circuit (2438) can determine whether a mechanical defect (e.g., belt slip or belt skip of the first or second motor (310 / 410), etc.) occurred within their respective power packs at the time of this timestamp of 4:10:36 PM ET on November 3, 2025. Additionally, the first power pack other process circuit (2410) and the second power pack other process circuit (2438) can each also calculate pinion angle values ​​for the steer-by-wire system for a specific timestamp of 4:10:36 p.m. 3

[0377] Although exemplary embodiments have been described in detail above, it should be understood that various changes, substitutions, and modifications may be made in this specification without departing from the spirit and scope of the application as defined in the appended claims.

[0378] Furthermore, the scope of this application is not intended to be limited to specific embodiments of the processes, machines, manufactures, and compositions, means, methods, and steps of materials described herein. As will be readily understood by those skilled in the art from this disclosure, existing or subsequently developed processes, machines, manufactures, compositions, means, methods, or steps that perform substantially the same function or achieve substantially the same results as the corresponding embodiments described herein may be utilized according to the said embodiments and alternative embodiments. Accordingly, the appended claims are intended to include such processes, machines, manufactures, compositions, means, methods, or steps within their scope.

[0379] Cross-reference to related patent application(s)

[0380] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 753,906, filed February 4, 2025, titled “PINION ANGLE SENSING WITH TWO MOTOR PPK POSITION SENSOR AND CAN FD COMMUNICATION,” the entire contents of said application incorporated herein by reference.

Claims

Claim 1 A steer-by-wire system comprises: a first power pack including a first motor, a first motor position sensor configured to detect a first power pack motor position of the first motor, a first controller configured to receive the first power pack motor position from the first motor position sensor and control the first motor, and a time generator circuit; and a second power pack including a second motor, a second motor position sensor configured to detect a second power pack motor position of the second motor, and a second controller configured to receive the second power pack motor position from the second motor position sensor and control the second motor. A steer-by-wire system comprising a steering rack operably coupled to the first motor of the first power pack and the second motor of the second power pack, the steering rack configured to be linearly movable in response to rotation of at least one of the first motor and the second motor, wherein the time generator circuit of the first power pack is configured to generate motor position timing and provide it to both the first controller and the second controller, and the time generator circuit is the only motor position timestamp generating component between the first power pack and the second power pack of the steer-by-wire system. Claim 2 A steer-by-wire system according to claim 1, wherein the first power pack motor position and the second power pack motor position are generated by the first motor position sensor and the second motor position sensor, respectively, without any timestamp indicating the time when the first and second power pack motor positions are measured by the first and second motor position sensors, respectively. Claim 3 A steer-by-wire system according to paragraph 2, wherein the motor position timing generated by the time generator circuit of the first power pack is provided to the second controller of the second power pack through the first controller of the first power pack. Claim 4 A steer-by-wire system according to paragraph 3, wherein the second controller is configured to obtain a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing received from the first controller to an instance of the second power pack motor position received by the second controller from the second motor position sensor. Claim 5 In paragraph 4, the instance of the second power pack motor position is received simultaneously with the motor position timing, in a steer-by-wire system. Claim 6 In paragraph 4, the instance of the second power pack motor position is received immediately after the reception of the motor position timing, in a steer-by-wire system. Claim 7 In paragraph 4, the instance of the second power pack motor position is received immediately before the reception of the motor position timing, in a steer-by-wire system. Claim 8 In claim 7, the first controller obtains the first combined motor position reading including a timestamp for the first power pack by adding the motor position timing received from the first controller to an instance of the first power pack motor position received by the first controller from the first motor position sensor; and is further configured to provide the first combined motor position reading including a timestamp for the first power pack to the second controller, wherein the second controller extracts the motor position timing generated by the time generator circuit from the first combined motor position reading including a timestamp for the first power pack, a steer-by-wire system. Claim 9 A steer-by-wire system according to claim 8, wherein the second controller is further configured to transmit back to the first controller the second combined motor position reading containing a timestamp for the second power pack. Claim 10 A steer-by-wire system according to claim 9, wherein the first controller is configured to generate a first pinion angle value using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack, and the second controller is configured to generate a second pinion angle value using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack. Claim 11 A steer-by-wire system according to claim 9, wherein the first controller is configured to detect a first mechanical defect of the first motor using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack, and the second controller is configured to detect a second mechanical defect of the second motor using the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack. Claim 12 A steer-by-wire system according to claim 1, wherein the first operation of the first power pack and the second operation of the second power pack are not synchronized in time. Claim 13 A steer-by-wire system according to claim 12, wherein the motor position timing generated by the time generator circuit of the first power pack is available to the second power pack and is the sole source of motor position timing information used by it. Claim 14 In claim 1, the first controller and the second controller: at a first time point, the first controller receives the first power pack motor position and the motor position timing; the first controller obtains a first combined motor position reading including a timestamp for the first power pack by adding the first power pack motor position and the motor position timing; the first controller transmits the first combined motor position reading including a timestamp for the first power pack to the second controller; the second controller extracts the motor position timing from the first combined motor position reading including a timestamp for the first power pack; and the second controller obtains a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing to an instance of the second power pack motor position. A steer-by-wire system further configured to transmit to the first controller, by the second controller, a second combined motor position reading including a timestamp for the second power pack. Claim 15 A steer-by-wire system, wherein the first controller and the second controller are further configured to: manage a first operation of the first power pack by the first controller using both the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack; and manage a second operation of the second power pack by the second controller using both the first coupled motor position reading including a timestamp for the first power pack and the second coupled motor position reading including a timestamp for the second power pack. Claim 16 A steer-by-wire system according to claim 15, wherein the motor position timing generated by the time generator circuit of the first power pack is used as the sole timing information for synchronizing the first operation of the first power pack and the second operation of the second power pack. Claim 17 A steer-by-wire system according to claim 16, wherein the second power pack is configured without the time generator circuit and provides timing information for the second motor position measured by the second motor position sensor of the second power pack by relying solely on the time generator circuit of the first power pack. Claim 18 A method performed by a steer-by-wire system, comprising: an operation of receiving, at a first time point, by a first controller of a first power pack of the steer-by-wire system, a first motor position of a first motor of the first power pack measured by a first motor position sensor of the first power pack, and a motor position timing measured by a time generator circuit of the first power pack; an operation of obtaining a first combined motor position reading including a timestamp for the first power pack by adding the first motor position and the motor position timing by the first controller; an operation of transmitting the first combined motor position reading including a timestamp for the first power pack by the first controller to a second controller of a second power pack of the steer-by-wire system; an operation of extracting the motor position timing from the first combined motor position reading including a timestamp for the first power pack by the second controller; and by the second controller, at the second motor position of the second motor of the second power pack A method comprising: an operation of obtaining a second combined motor position reading including a timestamp for the second power pack by adding the motor position timing, wherein the second motor position is measured by a second motor position sensor of the second power pack and provided to the second controller; and an operation of transmitting the second combined motor position reading including a timestamp for the second power pack to the first controller by the second controller, wherein the steer-by-wire system further comprises a steering rack operably coupled to the first motor of the first power pack and the second motor of the second power pack, wherein the steering rack is configured to be linearly movable in response to the rotation of at least one of the first motor and the second motor, and the time generator circuit is the only motor position timestamp generating component between the first power pack and the second power pack of the steer-by-wire system. Claim 19 A method according to claim 18, comprising: an operation of managing a first operation of the first power pack using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack by the first controller; and an operation of managing a second operation of the second power pack using both the first combined motor position reading including a timestamp for the first power pack and the second combined motor position reading including a timestamp for the second power pack by the second controller. Claim 20 In claim 19, the first operation comprises an operation of generating a first pinion angle of the first motor and an operation of detecting a first mechanical defect of the first motor, and the second operation comprises an operation of generating a second pinion angle of the second motor and an operation of detecting a second mechanical defect of the second motor.

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