Patent Publication Number: US-2023159084-A1

Title: Steer by wire type steering apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit and priority from Korean Patent Application No. 10-2021-0160395, filed in the Republic of Korea on Nov. 19, 2021, the entire contents of which are hereby incorporated by reference for all purposes as if fully set forth into the present application. 
     BACKGROUND 
     Field of the Disclosure 
     Embodiments of the present disclosure relate to a steer by wire type steering apparatus. 
     Description of the Related Art 
     In general, power steering has been developed and applied to a vehicle steering apparatus to provide convenience in driving operation by assisting a driver&#39;s operating force of a steering wheel. Power steering was developed and applied in hydraulic type using hydraulic pressure, electro-hydraulic type using hydraulic pressure and electric power of the motor at the same time, and electric type using only electric power of the motor. 
     Recently, instead of removing a mechanical connection device such as a steering column or a universal joint or a pinion shaft between the steering wheel and the vehicle wheel, the Steer By Wire (SBW) type steering apparatus for steering a vehicle using an electric motor has been developed and applied. 
     However, in the case of such a steer by wire type steering system, since there is no mechanical connection between the steering shaft and the vehicle wheels, the driver&#39;s steering wheel rotation can rotate indefinitely, thereby reducing the driver&#39;s steering feeling and steering stability. 
     In addition, in the steer by wire type steering system, the need for a steer by wire type steering apparatus that can provide an accurate and continuous reaction force to the driver is emerging in order to provide an accurate sense of reaction force to the driver and to maintain a constant sense of reaction force transmitted to the steering wheel even when a high load is transmitted to the reduction gear that reduces the rotation speed of the motor. 
     SUMMARY OF THE DISCLOSURE 
     Embodiments of the present disclosure provide a steer by wire type steering apparatus capable of providing an accurate feeling of reaction force to the driver and maintain a constant feeling of reaction force transmitted to the steering wheel even when a high load is transmitted to the reduction gear. 
     In addition, the purpose of the embodiments of the present disclosure are not limited thereto, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. 
     A steer by wire type steering apparatus according to the embodiments of the present disclosure may comprise a steering shaft coupled to a steering wheel to rotate, a steering sensor for detecting a rotation direction of the steering shaft, an electronic controller for operating a steering motor in forward and reverse directions according to the rotation direction sensed by the steering sensor, a first pulley provided on a shaft of the steering motor, a second pulley provided on the steering shaft, a driving belt coupled to the first pulley and the second pulley, and a belt support member that rotationally supports one side of the driving belt and is coupled to a reduction gear housing. 
     According to the embodiments of the present disclosure, there is provided a steer by wire type steering apparatus that provide an accurate feeling of reaction force to the driver, and even if a high load is transmitted to the reduction gear, the feeling of reaction force transmitted to the steering wheel can be constantly maintained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a schematic view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure; 
         FIGS.  2  to  5    are perspective views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure; 
         FIGS.  6  and  7    are exploded perspective views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure; 
         FIG.  8    is a perspective view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure; 
         FIG.  9    is a cross-sectional view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure; 
         FIGS.  10  and  11    are front views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     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”. 
       FIG.  1    is a schematic view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure.  FIGS.  2  to  5    are perspective views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure.  FIGS.  6  and  7    are exploded perspective views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure.  FIG.  8    is a perspective view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure.  FIG.  9    is a cross-sectional view illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure.  FIGS.  10  and  11    are front views illustrating a steer by wire type steering apparatus according to the embodiments of the present disclosure. 
     Referring to  FIGS.  1  to  11   , a steer by wire type steering apparatus according to the embodiments of the present disclosure may include a steering shaft  103  coupled to a steering wheel  101  to rotate, a steering sensor  105  and  107  for detecting a rotation direction of the steering shaft  103 , an electronic controller  110  for operating a steering motor  120  in forward and reverse directions according to the rotation direction sensed by the steering sensor  105  and  107 , a first pulley  123  provided on a shaft  121  of the steering motor  120 , a second pulley  127  provided on the steering shaft  103 , a driving belt  125  coupled to the first pulley  123  and the second pulley  127 , and a belt support member  180  that rotationally supports one side of the driving belt  125  and is coupled to a reduction gear housing  150 . 
     In the steer by wire type steering apparatus according to embodiments of the present disclosure, an angle sensor  105  and a torque sensor  107  are combined as steering sensors for sensing the rotation direction of the steering shaft  103  on one side of the steering shaft  103  connected to the steering wheel  101 , when the driver manipulates the steering wheel  101 , the angle sensor  105  and the torque sensor  107  that sense it send an electric signal to the electronic controller  110  to operate the steering motor  120  and the pinion motor  130 . 
     The electronic controller  110  controls the steering motor  120  and the pinion motor  130  based on the electrical signals transmitted from the angle sensor  105  and the torque sensor  107  and the electrical signals transmitted from other sensors mounted on the vehicle. 
     The steering motor  120  is connected to a speed reduction gear  135  for reducing the number of revolutions of the steering motor  120 , and provides a reaction force to the steering shaft  103  so as to feel a steering reaction force in the opposite direction when the driver operates the steering wheel  101  during normal driving. And during autonomous driving, steering is performed by the control of the electronic controller  110  without the driver&#39;s will. 
     The pinion motor  130  slides the rack bar  111  connected to the pinion shaft  113  to steer the vehicle wheels  119  on both sides through the tie rod  115  and the knuckle arm  117 . 
     However, in the drawings in the embodiments of the present disclosure, for convenience of explanation, the angle sensor  105  and the torque sensor  107 , a vehicle speed sensor  104  for transmitting steering information to the electronic control device  110 , and a wheel rotation angle sensor  106  are illustrated as an example, but a motor position sensor, various radars, lidar, and image sensors such as cameras may be provided, and a detailed description thereof will be omitted below. 
     In such a steer by wire type steering apparatus, since the steering shaft  103  and the pinion shaft  113  are not mechanically connected and the driver&#39;s steering wheel  101  operation force is significantly reduced compared to a general steering device, there is a need for a mechanical device that eliminates the sense of heterogeneity felt by the driver and provides steering stability at high speeds. 
     Accordingly, the steering motor  120  adjusts the driver&#39;s steering wheel operation force by applying a rotational force in the opposite direction to the driver&#39;s steering will, that is, in the opposite direction to the direction in which the steering shaft  103  rotates. 
     As the steering sensors  105  and  107  for detecting the rotation direction of the steering shaft  103 , the angle sensor  105  and the torque sensor  107  are used as described above. The electronic controller  110  operates the steering motor  120  in forward and reverse directions according to the rotation direction sensed by the steering sensors  105  and  107 . 
     The speed reduction gear  190  for reducing the rotation speed of the steering motor  120  includes a first pulley  123  provided on a shaft  121  of the steering motor  120 , and a second pulley  127  provided on the steering shaft  103 , and a driving belt  125  coupled to the first pulley  123  and the second pulley  127 . 
     And, a belt support member  180  is provided which rotates and supports one side of the driving belt  125  and is coupled to the reduction gear housing  150 . Accordingly, the driving belt  125  is assembled to match the tension of the driving belt  125  when assembling the driving belt  125  and the tension of the driving belt  125  is maintained constant after assembly. 
     The belt support member  180  is provided in the steering column  100  separated from the pinion shaft  113 , the steering column  100  has a column housing  116  in which the steering shaft  103  is built-in. The steering column  100  is provided with a reduction gear housing  150  coupled to a column housing  116  in which the driving belt  125 , the first pulley  123 , the second pulley  127 , and the like are built-in, the steering motor  120 , the electronic controller  110  coupled to the reduction gear housing  150  and electrically connected to the steering motor  120 , a mounting bracket  112  for being fixed to the vehicle body. 
     The belt support member  180  includes a rotating member  181  supported on one side of the driving belt  125  and having a cylindrical shape, a bearing  187  supported on an inner circumferential surface of the rotating member  181 , a support shaft  183  coupled to an inner side of the bearing  187 , and a fixing member  185  coupled to the reduction gear housing  150  through the support shaft  183 . 
     The support shaft  183  includes a bearing coupling portion  183   a  to which the bearing  187  is coupled to an outer circumferential surface, and an eccentric support portion  183   b  having a central axis biased toward one side in a radial direction from a central axis of the bearing coupling portion  183   a  and having an outer diameter different from an outer diameter of the bearing coupling portion  183   a.    
     Therefore, when the support shaft  183  is rotated with respect to the central axis of the eccentric support portion  183   b , the rotation member  181  coaxially coupled to the bearing coupling portion  183   a  is movable in a direction closer to or away from the drive belt  125 . 
     The bearing support portion  183   d  is provided between the bearing coupling portion  183   a  and the eccentric support portion  183   b , and the bearing support portion  183   d  is formed by a stepped outer diameter on the outer peripheral surface of the bearing coupling portion  183   a . Then, the inner race of the bearing  187  is supported and coupled to the stepped portion connected between the bearing coupling portion  183   a  and the bearing support portion  183   d . The inner circumferential surface of the rotating member  181  is provided with a stepped portion  181   a  to which the outer race of the bearing  187  is supported and coupled. 
     The belt support member  180  includes a support member  182  that supports one side of the eccentric support portion  183   b  and supports the rotating member  181  toward the driving belt  125 . 
     The support member  182  is screwed to the reduction gear housing  150  and supports one side of the outer peripheral surface of the eccentric support portion  183   b  to fix the position of the support shaft  183 . Accordingly, the rotating member  181  maintains a constant force for supporting the driving belt  125 . 
     The support shaft  183  is provided with a through hole  183   c  passing through an inside of the support shaft  183  along the central axis of the eccentric support portion  183   b , and the fixing member  185  is inserted into the through hole  183   c.    
     Accordingly, the operator adjusts the tension of the driving belt  125  while rotating the support shaft  183  in a state in which the fixing member  185  is not completely fastened when assembling the support shaft  183 . Thereafter, the tension of the driving belt  125  is maintained by completely fastening the fixing member  185  and screwing the supporting member  182  to the reduction gear housing  150 . 
     And an insertion groove  155  into which the eccentric support portion  183   b  is inserted is provided in the reduction gear housing  150 , and a guide hole  151  into which the support member  182  is inserted is provided on a side surface of the insertion groove  155 . 
     The insertion groove  155  is formed to have the same diameter as the eccentric support portion  183   b , so that the eccentric support portion  183   b  is supported by the insertion groove  155  and rotates during assembly. Then the support member  182  supports the eccentric support portion  183   b  and is fixed to the guide hole  151 . 
     In addition, the reduction gear housing  150  is provided with a fixing hole  157  to which the fixing member  185  is coupled to the bottom of the insertion groove  155 , so that the fixing member  185  is fastened to the fixing hole  157  to fix the support shaft  183 . 
     The fixing member  185  includes a coupling portion  185   a  inserted into the through hole  183   c  and coupled to the fixing hole  157 , and a shaft support portion  185   b  having an enlarged diameter at one end of the coupling portion  185   a  and supporting the bearing coupling portion  183   a  of the support shaft  183  in an axial direction. And the fixing member  185  supports and fixes the support shaft  183  in the axial direction. 
     The guide hole  151  formed in the reduction gear housing  150  includes an inner hole  151   a  into which a body portion of the support member  182  is inserted and screwed, and an outer hole  151   b  having an inner diameter larger than that of the inner hole  151   a  and in which a head portion of the support member  182  is located. 
     In addition, as shown in  FIGS.  10  and  11   , the belt support member  180  includes a rotation preventing member  170  coupled to an outer circumferential surface of the eccentric support portion  183   b  to prevent rotation of the support shaft  183 . 
     Here, the rotation preventing member  170  includes a locking member  171  having a fixing protrusion  174  coupled to an outer circumferential surface of the eccentric support portion  183   b  at one end and rotatably coupled to the reduction gear housing  150  at an other end, and an elastic member  157  having one end supported by the reduction gear housing  150  and an other end supported by the locking member  171  to support the locking member  171  toward the eccentric support portion  183   b.    
     In addition, a coupling protrusion  184  engaged with the fixing protrusion  174  of the locking member  171  may be formed on the outer circumferential surface of the eccentric support portion  183   b , and the other end of the locking member  171  is coupled to the reduction gear housing  150  by a hinge  159 . 
     Accordingly, the operator adjusts the tension of the driving belt  125  while rotating the support shaft  183 , and then completely fastens the fixing member  185 . And, by coupling the fixing protrusion  174  of the locking member  171  to the coupling protrusion  184  of the eccentric support portion  183   b , the support shaft  183  is not rotated and maintains its original position. 
     In addition, a protruding bulkhead  152  may be provided inside the reduction gear housing  150 , a support groove  154  in which the elastic member  157  is inserted and supported is provided in the protruding bulkhead  152 . Accordingly, the separation of the elastic member  157  is prevented. 
     As described above, according to the embodiments of the present disclosure, there is provided a steer by wire type steering apparatus capable of providing an accurate feeling of reaction force to the driver and maintain a constant feeling of reaction force transmitted to the steering wheel even when a high load is transmitted to the reduction gear. 
     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.