Patent Publication Number: US-2023142843-A1

Title: Steering-assisting device

Description:
TECHNICAL FIELD 
     The present embodiments relate to a steering assist device. 
     BACKGROUND ART 
     In general, a vehicle adopts a power steering assist device as means to ensure steering stability by reducing the steering force of the steering wheel. Conventionally, hydraulic power steering (HPS) has been widely used as power steering assist devices but are recently being replaced with electric power steering (EPS) which facilitates steering using a motor, instead of a hydraulic pump, and is eco-friendly. 
     To achieve the above-described goals, the electronic steering system adopts an electronic controller unit (ECU), which means an electronic control device that controls the status of the vehicle&#39;s engine, automatic transmission, or ABS by a computer. Further, with the development of vehicle and computer performance, the ECU is also serving to control all parts of the vehicle including the driving system, the braking system, and the steering system, as well as to control the automatic transmission. 
     Recently, as the ECU plays an important role, requirements for the reliability of the ECU are increasing. Accordingly, rather than relying on a single ECU, a redundancy system is adopted which includes a redundant ECU that replaces the existing ECU when the ECU fails to normally work or stops working due to errors or physical shocks to the existing ECU. 
     As the redundancy system widens its scope, the steering motor, such as the one for moving the rack bar, also adopts a dual winding motor which has two or more coil windings around a single motor to allow for a normal operation when the coil, a key component of the motor, stops working or fails to work due to errors or physical shocks, like in the above-described ECU, as a part of the redundancy system. 
     As the dual winding motor is driven, vibration may occur. A need exists for a method for minimizing such vibration. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     In the foregoing background, the disclosure provides a steering assist device which is connected with the rack bar to minimize the vibration caused according to the winding pattern when at least one coil fails. 
     Technical Solution 
     To achieve the foregoing objectives, in an aspect, the disclosure provides a steering assist device comprising a stator around which a plurality of coils are wound, a rotator rotated by the stator, and a connector transferring a rotational force, generated as the rotator rotates, to a rack bar, wherein the connector is connected to the rack bar in a direction of minimizing vibration generated depending on a winding pattern of the stator when at least one of the coils of the stator fails. 
     Advantageous Effects 
     According to the disclosure, the steering assist device changes the direction of connection with the rack bar depending on the winding pattern of the stator, reducing noise and vibration in the steering assist device when the coil of the stator fails. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view exemplarily illustrating an example of a steering assist device according to an embodiment of the disclosure; 
         FIG.  2    is a view illustrating a winding pattern of a stator according to an embodiment; 
         FIG.  3    is a view exemplarily illustrating the direction and strength of vibration in a steering assist device when the second U-phase, V-phase, and W-phase coils in the winding pattern of the stator of  FIG.  2    according to an embodiment; 
         FIG.  4    is a view illustrating an example in which a connector transfers a rotational force to a rack bar through a driving belt according to an embodiment; 
         FIG.  5    is a view illustrating a winding pattern of a stator according to another embodiment; 
         FIG.  6    is a view exemplarily illustrating the direction and strength of vibration in a steering assist device when the second U-phase, V-phase, and W-phase coils in the winding pattern of the three-phase coils of  FIG.  5    according to an embodiment; 
         FIG.  7    is a view illustrating that a connector transfers a rotational force to a rack bar through a driving belt according to another embodiment; 
         FIGS.  8 A and  8 B  are views illustrating that a connector is connected in a direction in which vibration is generated to reduce the vibration according to an embodiment; 
         FIGS.  9 A and  9 B  are views illustrating that a connector is connected in a direction in which vibration is generated to reduce the vibration according to another embodiment; and 
         FIG.  10    is a view exemplarily illustrating that a housing is fixed with a rack bar according to an embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     In the following description of examples or embodiments of the present disclosure, reference will be made to the accompanying drawings in which it is shown by way of illustration specific examples or embodiments that can be implemented, and in which the same reference numerals and signs can be used to designate the same or like components even when they are shown in different accompanying drawings from one another. Further, in the following description of examples or embodiments of the present disclosure, detailed descriptions of well-known functions and components incorporated herein will be omitted when it is determined that the description may make the subject matter in some embodiments of the present disclosure rather unclear. The terms such as “including”, “having”, “containing”, “constituting” “make up of”, and “formed of” used herein are generally intended to allow other components to be added unless the terms are used with the term “only”. As used herein, singular forms are intended to include plural forms unless the context clearly indicates otherwise. 
     Terms, such as “first”, “second”, “A”, “B”, “(A)”, or “(B)” may be used herein to describe elements of the disclosure. Each of these terms is not used to define essence, order, sequence, or number of elements etc., but is used merely to distinguish the corresponding element from other elements. 
     When it is mentioned that a first element “is connected or coupled to”, “contacts or overlaps” etc. a second element, it should be interpreted that, not only can the first element “be directly connected or coupled to” or “directly contact or overlap” the second element, but a third element can also be “interposed” between the first and second elements, or the first and second elements can “be connected or coupled to”, “contact or overlap”, etc. each other via a fourth element. Here, the second element may be included in at least one of two or more elements that “are connected or coupled to”, “contact or overlap”, etc. each other. 
     When time relative terms, such as “after,” “subsequent to,” “next,” “before,” and the like, are used to describe processes or operations of elements or configurations, or flows or steps in operating, processing, manufacturing methods, these terms may be used to describe non-consecutive or non-sequential processes or operations unless the term “directly” or “immediately” is used together. 
     In addition, when any dimensions, relative sizes etc. are mentioned, it should be considered that numerical values for an elements or features, or corresponding information (e.g., level, range, etc.) include a tolerance or error range that may be caused by various factors (e.g., process factors, internal or external impact, noise, etc.) even when a relevant description is not specified. Further, the term “may” fully encompasses all the meanings of the term “can”. 
     A steering assist device  10  according to an embodiment is described below with reference to  FIG.  1   . 
       FIG.  1    is a view exemplarily illustrating an example of a steering assist device  10  according to an embodiment of the disclosure. 
     Referring to  FIG.  1   , a steering assist device  10  according to an embodiment of the disclosure may include a rotator  110 , a stator  120 , a connector  130 , and a housing  140 . 
     The steering assist device may be a motor that includes the rotator  110  formed of a permanent magnet and the stator  120  surrounding the rotator  110  and having a coil winding and converts electric energy into mechanical energy as the rotator  110  is axially rotated by the magnetic field generated between the stator  120  and the rotator  110  according to application of current to the stator  120 . 
     The steering assist device  10  transfers the rotational force to the rack bar  410  and is connected to the rack bar  410  in the direction along which the vibration generated thereby is minimized, reducing the vibration of the steering assist device  10 . 
     The stator  120  may receive the rotator  110  in the center. The stator  120  may include a plurality of coil slots for receiving the coil. Specifically, the stator  120  may include a coil winding in a thin metal line through which current may flow to generate a magnetic field. The stator  120  may include the coil slots for receiving the coil. 
     The coil slots may be arranged while maintaining a predetermined distance from the rotator  110 . An even number of coil slots may be formed. The plurality of coil slots may be arranged while being spaced apart from each other along the circumferential direction. Each coil slot may include two poles protruding from the stator  120  to the rotator  110  and which the conductive line is wound around. Each coil slot may implement three phases, which may be denoted by U, V, and W. 
     The rotator  110  may be rotated by the stator  120  and be formed of a permanent magnet. Further, if current is applied to the stator  120 , the rotator  110  may be rotated clockwise or counterclockwise around the rotational axis depending on the magnetic field relationship between the rotator  110  and the stator  120 . 
     The connector  130  may transfer the rotational force, generated as the rotator  110  rotates, to the rack bar  410 . The connector  130  is connected to the center of the rotator  110  and may include a shaft that is formed in the direction of the rotational axis in the center of the rotator  110  to rotate alongside the rotator  110 . 
     The housing  140  may receive the stator  120  and the rotator  110 . The housing  140  may form the outer appearance of the steering assist device  10 . The housing  140  may be formed in a cylindrical shape, but is not limited to a specific shape as long as its shape is capable of receiving the stator  120  and the rotator  110  and the rotator  110  is rotatable therein. The housing  140  may be formed of a metal to remain in shape even at a high temperature. 
       FIG.  2    is a view illustrating a winding pattern of a stator  120  according to an embodiment. 
     Referring to  FIG.  2   , the stator  120  may have a dual winding structure in which first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils and second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′) and W-phase ( 213 ,  213 ′) coils are wound around the stator  120 . Specifically, the stator  120  may configure a winding pattern as shown in  FIG.  2    by implementing three phases in each of the plurality of coil slots, and the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils and the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′) and W-phase ( 213 ,  213 ′) coils may be wound in pair. In other words, there may be 12 coil slots implementing the three phases. 
     Specifically, among the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils, two pairs of the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils are wound clockwise in the order of U-phase, V-phase, and W-phase, and two pairs of the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) may be wound counterclockwise in the order of U-phase, V-phase, and W-phase. 
       FIG.  3    is a view exemplarily illustrating the direction and strength of vibration in a steering assist device  10  when the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils in the winding pattern of the stator of  FIG.  2    according to an embodiment. 
     Referring to  FIGS.  3   , T1 to T12 respectively may correspond to the positions of the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils and the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils of  FIG.  2   . For example, the first W phase  203  may correspond to T11 of  FIG.  3   . 
     When the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils and continuous second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils are wound around the stator  120  in a symmetrical structure, the connector  130  may be connected with the rack bar  410  in a direction of the middle of the angle between the center of the stator  120  and the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils. Specifically, it may be shown that in the arrangement of the three-phase coils in  FIG.  2   , the vibration strength and direction are shown in the direction of the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′), and a vibration strength similar to that of the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) is shown in the symmetrical direction, i.e., the direction of the continuous second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′). Accordingly, to minimize the vibration of the steering assist device, the connector  130  may be connected with the rack bar  410  in the direction of the middle of the angle between the center of the stator  120  and the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′). In other words, it may be the middle value of the angle between the center of the stator and T1 and T8. 
     The angle of connection between the steering assist device  10  and the rack bar  410  is not limited to the above-described direction of the middle of the angle between the center of the stator  120  and the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) but may rather be varied depending on actual measurements. As an example, as shown in  FIG.  3   , if the vibration is measured as largest in the direction of T9, the steering assist device  10  may be connected with the rack bar  410  in the direction corresponding to T9. 
       FIG.  4    is a view illustrating an example in which a connector  130  transfers a rotational force to a rack bar  410  through a driving belt  420  according to an embodiment. 
     Referring to  FIG.  4   , the connector  130  may include a driving belt  420  that transfers the rotational force, generated as the rotator  110  rotates, to the rack bar  410 . Specifically, the connector  130  may include a motor pulley  430  and a nut pulley  450  to transfer the rotational force through the driving belt  420 . The motor pulley  430  may be coupled to one side of the driving belt  420  to transfer the rotational force of the rotator  110  via the driving belt  420 , and the nut pulley  450  may be mounted on the outer circumferential surface of one side of the ball nut  450  and be coupled to the other side of the driving belt  420 . Here, the ball nut  450  may be coupled with the rack bar  410  via a ball and rotate to slide the rack bar  410 . In other words, if current is applied to the stator  120  so that the rotator  110  is rotated by the magnetic field relationship between the coil wound around the stator and the permanent magnet of the rotator  110 , and the shaft is thus rotated, the motor pulley  430  is rotated, and the nut pulley  450  connected to the driving belt  420  is rotated, and thus, the ball nut  450  coupled with the nut pulley  450  is rotated, reciprocating the rack bar  410 . 
     The connector  130  may be connected with the rack bar  410  through the driving belt  420  so that the belt tension of the driving belt  420  faces in the direction of the vibration due to the winding pattern of the stator  120  as shown in  FIG.  3   . In other words, the belt tension of the driving belt  420  may be formed as indicated by the arrow of  FIG.  4   . 
       FIG.  5    is a view illustrating a winding pattern of a stator  120  according to another embodiment. 
     Referring to  FIG.  5   , the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils and continuous second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils are alternately wound around the stator  120  and, when the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils fail, the connector  130  may be connected with the rack bar  410  in the direction along which the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils are wound. Specifically, as shown in  FIG.  5   , the first U-phase ( 201 ), V-phase ( 202 ) and W-phase ( 203 ) coils may be wound counterclockwise in the order of the first U-phase ( 201 ′), V-phase ( 202 ) and W-phase ( 203 ) coils, the second U-phase ( 211 ), V-phase ( 212 ), and W-phase ( 213 ) coils may be wound counterclockwise in the order of the second U-phase ( 211 ), V-phase ( 212 ), and W-phase ( 213 ) coils, next to the above-described first U-phase ( 201 ′), V-phase ( 202 ) and W-phase ( 203 ) coils, the other first U-phase ( 201 ′), V-phase ( 202 ′) and W-phase ( 203 ′) coils may be wound in the same order as the above-described first U-phase ( 201 ), V-phase ( 202 ) and W-phase ( 203 ) coils, next to the second U-phase ( 211 ), V-phase ( 212 ), and W-phase ( 213 ) coils, and the other second U-phase ( 211 ′), V-phase ( 212 ′), and W-phase ( 213 ′) coils may be wound in the same order as the above-described second U-phase ( 211 ), V-phase ( 212 ), and W-phase ( 213 ) coils, next to the second U-phase ( 211 ), V-phase ( 212 ), and W-phase ( 213 ) coils. When the winding pattern of the stator  120  is the above-described winding pattern, the connector  130  may be connected with the rack bar  410  in the direction along which the first U-phase ( 201 ), V-phase ( 202 ) and W-phase ( 203 ) coils are wound or the other first U-phase ( 201 ′), V-phase ( 202 ′) and W-phase ( 203 ′) coils are wound. 
       FIG.  6    is a view exemplarily illustrating the direction and strength of vibration in a steering assist device  10  when the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils in the winding pattern of the three-phase coils of  FIG.  5    according to an embodiment. 
     Referring to  FIG.  6   , it may be shown that in the arrangement of the three-phase coils of  FIG.  5   , the vibration strengths and directions are shown to two opposite sides of the directions of the continuous first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′). Accordingly, the connector  130  may be connected with the rack bar  410  in the direction in which the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils are wound to minimize the vibration of the steering assist device  10 . The connector  130  may be connected in the direction in which any one coil among the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils is wound and, in the case shown in  FIG.  6   , the connector  130  may be connected in the direction of T8. In contrast, when the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils fail, the vibration strengths and directions will be shown to two opposite sides of the directions of the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) so that the connector  130  may be connected with the rack bar  410  in the direction in which the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils are wound to minimize the vibration of the steering assist device  10 . 
     According to the foregoing description, the steering assist device  10  may change the direction of connection with the rack bar  410  depending on the winding pattern in the winding pattern of the stator  120 , thereby minimizing the vibration and noise of the driven steering assist device  10  when the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils fail. 
       FIG.  7    is a view illustrating an example in which a connector  130  transfers a rotational force to a rack bar  410  through a driving belt  420  according to another embodiment. 
     Referring to  FIG.  7   , the connector  130  may transfer the rotational force to the rack bar  410  through the driving belt  420  to minimize the vibration direction and strength of the steering assist device  10  shown in  FIG.  6   . The connector  130  may be connected so that the belt tension of the driving belt  420  is formed in the direction of the vibration due to the winding pattern of the stator  120  as shown in  FIG.  6   . When there are two or more vibration directions as shown in  FIG.  6   , the connector  130  may be connected in any one of the two directions. In other words, the connector  130  may be connected with the rack bar  410  in any one direction of T2 or T8. 
     The connector  130  may transfer the rotational force of the rotator  110  to the rack bar  410  using a reducer including a worm shaft and a worm wheel. Specifically, the connector  130  may be connected with the reducer in the direction of minimizing the vibration and noise of the steering assist device  10  depending on the winding pattern, and the reducer may reciprocate the rack bar  410  through the pinion gear by the rotational force received from the connector  130 . 
       FIGS.  8 A and  8 B  are views illustrating that a connector  130  is connected in a direction in which vibration is generated to reduce the vibration according to an embodiment. 
     Referring to  FIG.  8 A , in a case where the stator  120  of  FIG.  8 A  has a coil arrangement as shown in  FIG.  2   , and the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils fail, if the rotator is rotated by the current applied only to the first U-phase ( 201 ,  201 ′), V-phase ( 202 ,  202 ′) and W-phase ( 203 ,  203 ′) coils, vibration may be generated in the left and right directions as shown in  FIG.  8 A  (e.g., the T9 and T4 directions of  FIG.  3   ). Therefore, to reduce the vibration of the steering assist device  10 , referring to  FIG.  8 B , the connector  130  may be connected with the stator  120  in the direction in which vibration is generated, by changing the angle at which the stator  120  is disposed. The vibration of the steering assist device  10  may be reduced by holding the steering assist device  10 , which vibrates in the upper and lower directions, with the belt tension, which is formed towards the rack bar  410  (lower direction) by the driving belt  420 . In other words, as the stator  120  rotates counterclockwise so that the direction of vibration becomes the upper/lower direction, the vibration of the steering assist device  10  may be reduced. 
       FIGS.  9 A and  9 B  are views illustrating that a connector  130  is connected in a direction in which vibration is generated to reduce the vibration according to another embodiment. 
     Referring to  FIG.  9   , in  FIG.  9 A , when the second U-phase ( 211 ,  211 ′), V-phase ( 212 ,  212 ′), and W-phase ( 213 ,  213 ′) coils fail depending on the winding pattern as shown in  FIG.  8 A , vibration may be generated in the left/right direction. Accordingly, to reduce the vibration of the steering assist device  10 , the connector  130  may be connected with the stator disposed so that the direction of vibration of the stator  120  faces the rack bar, as shown in  FIG.  9 A . The position of the stator  120  is shifted from the upper surface to side surface of the rack bar  410 , so that the rack bar  410  is positioned in the direction of vibration of the steering assist device  10  and, as the steering assist device  10  is connected with the rack bar  410  through the driving belt  420 , the vibration of the steering assist device  10  in the left/right direction may be reduced. 
     In the disclosure, a change in the position of connection of the steering assist device  10  may be defined as a change in the connector  130 . 
       FIG.  10    is a view exemplarily illustrating that a housing  140  is fixed with a rack bar  410  according to an embodiment. 
     Referring to  FIG.  10   , the connector  130  may be connected with the rack bar  410  so that one surface of the housing  140  facing the rack bar  410  is spaced apart. Specifically, the connector  130  may be connected with the rack bar  410  in the direction of minimizing the vibration and noise of the steering assist device  10  depending on the winding pattern of the stator  120 . To further reduce vibration and noise, the connector  130  may be connected while being spaced apart from the rack bar  410  by a predetermined interval. Further, the housing  140  may be coupled by a bolting structure so that one surface of the housing  140  facing the rack bar  410  is fixed, thereby further reducing the vibration and noise of the steering assist device  10 . Further, the housing  140  may be coupled by a bolting structure so that one surface of the housing  140  facing the rack housing surrounding the rack bar  410  is fixed to the rack housing. 
     As described above, according to the disclosure, the steering assist device  10  may change the direction of connection with the rack bar  410  depending on the winding pattern of the stator  120 , thereby minimizing the vibration and noise of the steering assist device  10  when the coil of the stator  120  fails. 
     The above description has been presented to enable any person skilled in the art to make and use the technical idea of the present disclosure, and has been provided in the context of a particular application and its requirements. Various modifications, additions and substitutions to the described embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. The above description and the accompanying drawings provide an example of the technical idea of the present disclosure for illustrative purposes only. That is, the disclosed embodiments are intended to illustrate the scope of the technical idea of the present disclosure. Thus, the scope of the present disclosure is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the claims. The scope of protection of the present disclosure should be construed based on the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included within the scope of the present disclosure. 
     
       
     
     
       
     
     
       
     
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean Patent Application No. 10-2020-0045489 filed in the Korean Intellectual Property Office on Apr. 14, 2020, the disclosure of which is incorporated by reference herein in its entirety.