Abstract:
A structure of a lever for a drive-by-wire system installed in a vehicle may include a lever body rotatably mounted on a console surface of the vehicle, and an acceleration lever and a steering roller installed in the lever body, such that it is possible to control a change of a gear shift stage, acceleration, and a change of a proceeding direction of the vehicle in a unified manner, and there is no risk of erroneous manipulations of an accelerator pedal and a brake pedal, and acceleration and a proceeding direction is changed using a finger, thereby improving performance in manipulating the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Korean Patent Application No. 10-2014-103183, filed on Aug. 11, 2014, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a structure of a lever for a drive-by-wire system installed in a vehicle, and more particularly, to a structure of a lever for a drive-by-wire system, in which a lever body is rotatably mounted on a console surface of the vehicle, and an acceleration lever and a steering roller are installed in the lever body, such that it is possible to control a change of a gear shift stage, acceleration, and a change of a proceeding direction of the vehicle in a unified manner. 
     2. Description of Related Art 
     In general, a drive-by-wire system, so-called an X-by-wire system, which is applied to a vehicle, refers to a system in which an electrical connection structure which uses an actuator, an electronic control unit (ECU), and the like, is substituted for a mechanical connection structure that is positioned between a control mechanism (for example, a gear shift lever) in the vehicle and an apparatus (for example, a transmission), which is actually operated. 
     The drive-by-wire system is widely classified into a throttle-by-wire system, a brake-by-wire system, a shift-by-wire system, a steer-by-wire system, and the like. 
     The throttle-by-wire system controls flows of air and fuel, which flow into cylinders, in accordance with a position of an accelerator pedal in an electrical manner, the brake-by-wire system brakes the vehicle in accordance with an electrical signal from a brake pedal, the shift-by-wire system performs a gear shift operation of the vehicle in accordance with an electrical signal from the gear shift lever, and the steer-by-wire system changes a direction of the vehicle in accordance with an electrical signal from a steering wheel. 
     The drive-by-wire system has advantages in that the drive-by-wire system is very excellent in terms of vibration and noise characteristics in comparison with a mechanical system, is hardly affected by a spatial restriction unlike the mechanical system, and may provide improved driving performance because a steering device, a brake device, a suspension device, and the like are operated together. 
     However, the drive-by-wire system of the vehicle in the related art has problems of the vehicle in the related art as they are, because the mechanical connection structure is just substituted by the electronic connection structure, but there is no manipulation mechanism capable of maximizing the advantages of the drive-by-wire system. 
     That is, there are problems in that a driver is injured by the steering wheel at the time of a vehicle collision accident, there is a risk of an accident due to erroneous manipulation when the driver manipulates the accelerator pedal and the brake pedal with the right foot, and there is a problem in that the driver repeatedly manipulates the pedals when the vehicle travels on a highway or over a long distance which causes an ankle injury. 
     There is a problem in that because the gear shift lever protrudes from the console surface even at normal times, an accommodation space, buttons for performing functions necessary to drive the vehicle, and the like cannot be freely disposed at the periphery of the gear shift lever. 
     The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY  
     Various aspects of the present invention are directed to providing a structure of a lever for a drive-by-wire system, which may control a change of a gear shift stage, acceleration, and a change of a proceeding direction of a vehicle in a unified manner, by integrating functions of an acceleration pedal and a steering wheel into a lever of the vehicle. 
     The present invention has also been made in an effort to provide a structure of a lever for a drive-by-wire system, in which there is no risk of erroneously manipulating an accelerator pedal and a brake pedal, and acceleration and proceeding directions may be changed by a finger, thereby improving performance in manipulating a vehicle. 
     Technical problems to be achieved in an exemplary embodiment of the present invention are not limited to the aforementioned technical problems, and any other not-mentioned technical problems will be obviously understood from the description below by those skilled in the technical field to which the present invention pertains. 
     An exemplary embodiment of the present invention provides a structure of a lever for a drive-by-wire system, including, a lever body which is rotatably coupled to a console surface of a vehicle by a console side connecting portion formed at a lower side of the console surface and by a central axis rod, a rotary motor which rotates a lever body by rotating a motor gear that is fastened to engage with a central axis gear formed at one end of the central axis rod, a gear shift control unit which recognizes a change in position of a gear shift magnet embedded in the motor gear, and changes a gear shift stage of the vehicle, an acceleration lever which has a rear end rotatably coupled in the lever body, and protrudes through a first opening hole formed in one side surface of the lever body, a first elastic unit which is coupled to the acceleration lever in the lever body, and provides elastic restoring force to the acceleration lever, an acceleration control unit which recognizes a change in position of an acceleration magnet embedded in the acceleration lever, and accelerates the vehicle, a steering roller which is mounted in the lever body so as to be exposed through a second opening hole formed in the other side surface of the lever body, a second elastic unit which is coupled to the steering roller in the lever body, and provides elastic restoring force to the steering roller, and a steering control unit which recognizes a change in position of a steering magnet attached to an end of the steering roller, and changes a proceeding direction of the vehicle, in which a change of a gear shift stage, acceleration, and a change of a proceeding direction of the vehicle are controlled in a unified manner. 
     The structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention may further include a central axis groove portion which is coupled to the other end of the central axis rod, and has a plurality of curved teeth that curvedly protrudes, and a bullet unit which is disposed below the central axis groove portion, has a return spring and a solenoid coil embedded therein, pushes a bullet rod upward, in which the curved teeth of the central axis groove portion are caught by the bullet rod of the bullet unit, such that shift feeling is generated when the lever body is rotated. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, when the lever button disposed in the vehicle is operated, the lever body may pop up in a stepwise manner by the central axis groove portion and the bullet unit as the rotary motor is rotated, when a stop button disposed in the vehicle is operated, the lever body may be temporarily fixed as the rotation of the rotary motor is stopped, and when the stop button is operated, the gear shift control unit may recognize a position of the gear shift magnet embedded in the motor gear as a P-stage. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, in a state in which the stop button is operated, when the lever body is rotated rearward by a length corresponding to one curved tooth of the central axis groove portion, the gear shift control unit may recognize the changed position of the gear shift magnet as an R-stage, when the lever body is rotated rearward by a length corresponding to two curved teeth of the central axis groove portion, the gear shift control unit may recognize the changed position of the gear shift magnet as an N-stage, and when the lever body is rotated rearward by a length corresponding to three curved teeth of the central axis groove portion, the gear shift control unit may recognize the changed position of the gear shift magnet as a D-stage. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, in a state in which the stop button is operated, when the lever body is rotated forward, the rotary motor may be operated to return the lever body to an initial position (P-stage state) when the stop button is operated. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, when the lever body is rotated rearward by a length corresponding to four or more curved teeth of the central axis groove portion, the rotary motor may be operated to return the lever body to the position (D-stage state) at which the lever body is moved rearward by a length corresponding to three curved teeth of the central axis groove portion. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, the first elastic unit may be formed as a flat spring having a lateral cross section having a parallelogram shape, the second elastic unit may be formed as a flat spring having a cross section in a forward and rearward direction which has an elliptical shape, and the second elastic unit may be coupled to an upper portion of the first elastic unit. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, the first elastic unit may include a slit which is formed to penetrate a lower surface of the first elastic unit, and a contact portion which is disposed in the slit, forms a cantilevered beam structure having three sides spaced apart from the first elastic unit, and one side coupled to the first elastic unit, and comes into contact with the acceleration lever, and in which a manipulation of the acceleration lever does not affect the steering roller and the second elastic unit by the contact portion. 
     The structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention may further include, a rectilinear motor which is disposed at a rear side of the first elastic unit, and has a rectilinear rod that is movable forward and rearward, in which the rectilinear rod pushes one end of the first elastic unit and deforms the shape of the lateral cross section of the first elastic unit when the rectilinear rod is moved forward, and the shape of the second elastic unit is also deformed by the deformation of the shape of the first elastic unit, such that a steering effort of the steering roller is changed. 
     According to the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention, the rectilinear motor may recognize a signal generated by a lane departure warning system of the vehicle, and move the rectilinear rod maximally forward. 
     The present invention having the aforementioned configuration includes the lever body which is rotatably mounted on the console surface of the vehicle, and the acceleration lever and the steering roller which are installed in the lever body, so as to control a change of a gear shift stage, acceleration, and a change of a proceeding direction of the vehicle in a unified manner, thereby simplifying the structure in the vehicle, and reducing production costs of the vehicle. 
     By simplifying the structure in the vehicle, a safety device such as a large capacity airbag and a protective plate may be actively applied, and by eliminating the steering wheel and the accelerator panel in the vehicle, injuries to the driver may be prevented at the time of a collision accident. 
     According to an exemplary embodiment of the present invention, the accelerator pedal is substituted by the acceleration lever, thereby preventing an accident due to erroneous manipulations of the accelerator panel and the brake pedal, and removing inconvenience when the driver repeatedly manipulates the accelerator panel when the vehicle travels on a highway or over a long distance. 
     According to an exemplary embodiment of the present invention, the acceleration lever is manipulated using four fingers, and the steering roller is manipulated using a sensitive thumb, such that precise and comfortable manipulations are available, and operating characteristics of the vehicle may be remarkably increased. 
     According to an exemplary embodiment of the present invention, the central axis groove portion is coupled to the other end of the central axis rod, and the bullet unit is disposed below the central axis groove portion, such that shift feeling is generated at the lever body, thereby allowing the driver to clearly recognize the change of the gear shift stage when the driver manipulates the lever body to change the gear shift stage of the vehicle. 
     According to an exemplary embodiment of the present invention, the lever body returns to the P-stage state or the D-stage state by the rotary motor when the driver rotates the lever body forward, or rotates the lever body excessively rearward, thereby preventing the lever body from deviating due to manipulation mistakes of the driver. 
     According to an exemplary embodiment of the present invention, an expensive motor driven power steering (MDPS) motor, which was used in the related art to increase or decrease a steering effort of the steering wheel in proportion to a traveling state of the vehicle, is substituted by a simple rectilinear motor, thereby reducing costs of the vehicle. 
     The present invention is connected with the lane departure warning system of the vehicle, so as to maximize the steering effort of the steering roller by moving the rectilinear rod maximally forward when the vehicle deviates from the lane, thereby preventing an accident that occurs when the vehicle deviates from the lane, and remarkably improving safety of the vehicle. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating an appearance in which a structure of a lever for a drive-by-wire system according to an exemplary embodiment of the present invention is installed in a vehicle. 
         FIG. 2  is a bottom perspective view illustrating a connection structure between a lever body according to the exemplary embodiment of the present invention and a console surface. 
         FIG. 3  is a projection perspective view illustrating an overall appearance of the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention. 
         FIG. 4  is a projection perspective view illustrating the lever body and components in the lever body according to the exemplary embodiment of the present invention. 
         FIG. 5  is an exploded view illustrating the components in the lever body according to the exemplary embodiment of the present invention. 
         FIG. 6  is a projection side view illustrating a bullet unit and components in the bullet unit according to the exemplary embodiment of the present invention. 
         FIG. 7A ,  FIG. 7B ,  FIG. 7C ,  FIG. 7D ,  FIG. 7E  and  FIG. 7F  are side views illustrating rotation of a motor gear, and a position of a gear shift magnet in accordance with rotation of the lever body according to the exemplary embodiment of the present invention. 
         FIG. 8  is an exploded view illustrating an acceleration lever, a first elastic unit, a second elastic unit, and a steering roller according to the exemplary embodiment of the present invention. 
         FIG. 9A  is a perspective view illustrating an appearance of the first elastic unit according to the exemplary embodiment of the present invention. 
         FIG. 9B  is side views illustrating operational states of the acceleration lever and the first elastic unit according to the exemplary embodiment of the present invention. 
         FIG. 10A  is a side view illustrating an appearance in the lever body when a rectilinear rod according to the exemplary embodiment of the present invention is not moved forward. 
         FIG. 10B  is a side view illustrating an appearance in the lever body when the rectilinear rod according to the exemplary embodiment of the present invention is moved forward. 
         FIG. 11  is a flow chart illustrating logic for controlling a movement amount of the rectilinear rod according to whether a speed of a vehicle is increased or decreased, and whether a lane departure warning system is operated. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the technical field to which the present invention pertains may easily carry out the present invention. However, the present invention may be implemented in various different forms, and is not limited to the exemplary embodiments described herein. 
     A part irrelevant to the description will be omitted to clearly describe the present invention, and the same or similar constituent elements will be designated by the same reference numerals throughout the specification. 
     Terms or words used in the specification and the claims should not be interpreted as a general and dictionary meaning and should be interpreted as a meaning and a concept which conform to the technical spirit of the present invention based on a principle that an inventor can appropriately define a concept of a term in order to describe his/her own invention by the best method. 
       FIG. 1  is a schematic view illustrating an appearance in which a structure of a lever for a drive-by-wire system according to an exemplary embodiment of the present invention is installed in a vehicle,  FIG. 2  is a bottom perspective view illustrating a connection structure between a lever body  20  and a console surface  10  according to the exemplary embodiment of the present invention,  FIG. 3  is a projection perspective view illustrating an overall appearance of the structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention,  FIG. 4  is a projection perspective view illustrating the lever body  20  and components in the lever body  20  according to the exemplary embodiment of the present invention, and  FIG. 5  is an exploded view illustrating the components in the lever body  20  according to the exemplary embodiment of the present invention. 
     The structure of the lever for a drive-by-wire system according to the exemplary embodiment of the present invention includes the lever body  20 , a rotary motor  30 , a gear shift control unit  33 , an acceleration lever  40 , a first elastic unit  50 , an acceleration control unit  42 , a steering roller  60 , a second elastic unit  70 , and a steering control unit  62 , and the structure of the lever may control a change of a gear shift stage, acceleration, and a change of a proceeding direction of the vehicle in a unified manner. 
     As illustrated in  FIG. 1 , the lever body  20  according to an exemplary embodiment of the present invention may be installed on the console surface  10  in the vehicle, but may also be installed at various positions such as at the left side of a driver seat, or a position in the related art where a steering wheel is disposed, in consideration of the type of vehicle, a driver&#39;s preference, and the like. 
     Specifically, as illustrated in  FIG. 2 , the lever body  20  is rotatably coupled to the console surface  10  by a pair of console side connecting portions  11 , which is formed at a lower side of the console surface  10 , and a central axis rod  26 , and a through hole  23  is formed at a rear end of the lever body  20  so that the central axis rod  26  may pass through the through hole  23 . 
     The central axis rod  26  may be formed in an angled shape, and connected with the through hole  23  of the lever body  20 , which is formed to have a shape corresponding to the shape of the central axis rod  26 , or the central axis rod  26  may be connected with the lever body  20  by ultrasonic welding. 
     That is, the central axis rod  26  and the lever body  20  are coupled to each other so as to transmit rotational motion to each other, such that when the lever body  20  is rotated, the central axis rod  26  is also rotated, and on the contrary, when the central axis rod  26  is rotated, the lever body  20  is also rotated. 
     As illustrated in  FIGS. 2 and 3 , a central axis gear  25  is coupled to one end of the central axis rod  26  which is connected with the lever body  20 , and the central axis gear  25  is fastened so as to engage with a motor gear  31  installed below the central axis gear  25 . 
     A support plate  15  is installed below the console surface  10 , and the motor gear  31  is rotated in accordance with rotation of a rotary motor  30  coupled to the support plate  15 , thereby rotating the central axis gear  25  and the central axis rod  26 . 
     When the central axis gear  25  and the central axis rod  26  are rotated, the lever body  20 , which is coupled to the central axis rod  26 , is rotated, and pops up toward an upper side of the console surface  10  through an aperture  12  of the console surface  10 , and is stopped at a position at which the driver may conveniently manipulate the lever body  20 . 
     The manipulation of the lever body  20  may be performed by a lever button  13  and a stop button  14  disposed on the console surface  10  as illustrated in the exemplary embodiment, but the lever button  13  and the stop button  14  may be disposed anywhere in the vehicle (for example, on a center fascia or at a front side of a driver seat), and the manipulation of the lever body  20  may be automatically performed in some cases by recognizing whether or not the driver is seated on the driver seat, and the like. 
     In the exemplary embodiment of the present invention, the lever button  13  serves to allow the lever body  20  to pop up by rotating the rotary motor  30 , and the stop button  14  serves to stop the lever body  20  at a position desired by the driver. 
     A support frame  16  is additionally coupled to the support plate  15  disposed below the console surface  10 , and serves to prevent the lever body  20  from being excessively moved downward when the lever body  20  is moved downward through the aperture  12 . 
     The lever body  20  may be rotated in accordance with the rotation of the rotary motor  30  as described above, or may be rotated as the driver holds the lever body  20  with a hand and moves the lever body  20  forward and rearward. 
     A gear shift magnet ( 32  in  FIG. 7A ) is embedded in the motor gear  31  so as to indicate whether the motor gear  31  is rotated and a rotation amount of the motor gear  31 , and a gear shift control unit  33 , which is disposed to be adjacent to the motor gear  31 , recognizes a change in position of the gear shift magnet  32 , and changes the gear shift stage of the vehicle. 
     That is, when the driver operates the lever button  13 , the lever body  20  pops up, and in this case, the gear shift control unit  33  first recognizes the position of the gear shift magnet  32  in the motor gear  31 . Thereafter, when the driver holds the lever body  20  and moves the lever body  20  forward and rearward, the position of the gear shift magnet  32  is varied as the motor gear  31  is rotated, and the gear shift control unit  33  recognizes the change in position of the gear shift magnet  32  and changes the gear shift stage of the vehicle. 
     As illustrated in  FIGS. 4 and 5 , the acceleration lever  40 , the first elastic unit  50 , the steering roller  60 , the second elastic unit  70 , and the like are mounted in the lever body  20 . 
     The acceleration lever  40  is rotatably coupled to the lever body  20  as acceleration projections  41  formed at a rear end of the acceleration lever  40  are inserted into projection grooves  24  formed in an inner surface of the lever body  20 , and the acceleration lever  40  may protrude through a first opening hole  21  formed in one side surface (a lower surface in the illustrated exemplary embodiment) of the lever body  20 . 
     The first elastic unit  50  is disposed on an upper portion of the acceleration lever  40  and provides elastic restoring force to the acceleration lever  40 , and the propensity of the acceleration lever  40  to consistently protrude through the first opening hole  21  is maintained by the first elastic unit  50 . 
     An acceleration magnet is embedded in the acceleration lever  40  so as to indicate whether the acceleration lever  40  is rotated and a rotation amount of the acceleration lever  40 , and an acceleration control unit  42 , which is disposed to be adjacent to the acceleration lever  40 , recognizes a change in position of the acceleration magnet and accelerates the vehicle. 
     That is, like an operation of the driver pressing an accelerator pedal in the related art, when the driver holds the acceleration lever  40  with four fingers and then presses the acceleration lever  40 , the acceleration lever  40  is rotated about the acceleration projections  41 , and in this case, the acceleration control unit  42  recognizes a change in position of the acceleration magnet and accelerates the vehicle. 
     A second opening hole  22  is formed in the other side surface (an upper surface in the illustrated exemplary embodiment) of the lever body  20 , and the steering roller  60  is mounted in the lever body  20  so as to be exposed through the second opening hole  22 . 
     The second elastic unit  70  is disposed on a lower portion of the steering roller  60  and provides elastic restoring force to the steering roller  60 , and the propensity of the steering roller  60  to be positioned at a center instead of being rotated leftward and rightward is maintained by the second elastic unit  70 . 
     The second elastic unit  70  also serves to provide a steering effort (force required to change a direction of the vehicle) to the steering roller  60 . 
     A pair of steering magnets  61  is attached to a front end of the steering roller  60 , and the steering magnets  61  serve to indicate whether the steering roller  60  is rotated and a rotation amount of the steering roller  60 . 
     Like an operation of the driver rotating a steering wheel in the related art, when the driver positions the thumb on the steering roller  60  and rotates the steering roller  60  leftward and rightward, the positions of the steering magnets  61  attached to the steering roller  60  are varied, and in this case, the steering control unit  62 , which is disposed to be adjacent to the steering roller  60 , recognizes the change in position of the steering roller  60  and changes a proceeding direction of the vehicle. 
     Therefore, the driver may change the gear shift stage of the vehicle, accelerate the vehicle, and change the proceeding direction of the vehicle, just by holding the lever body  20  with one hand and rotating the lever body  20  forward and rearward, by pressing the acceleration lever  40  with four fingers, or by rotating the steering roller  60  leftward and rightward using the thumb. 
       FIG. 6  is a projection side view illustrating a bullet unit  34  and components in the bullet unit  34  according to the exemplary embodiment of the present invention, and  FIG. 7A ,  FIG. 7B ,  FIG. 7C ,  FIG. 7D ,  FIG. 7E  and  FIG. 7F  are side views illustrating the rotation of the motor gear  31  according to the rotation of the lever body  20 , and illustrating the position of the gear shift magnet  32 . 
     As illustrated in  FIGS. 4 and 6 , a central axis groove portion  27  on which a plurality of curved teeth  27   a  is formed is coupled to the other end (that is, a side opposite to a portion to which the central axis gear  25  is coupled) of the central axis rod  26 , and the bullet unit  34  is disposed below the central axis groove portion  27  and generates shift feeling when the lever body  20  is rotated. 
     Specifically, a return spring  36  is mounted in the bullet unit  34  and pushes a bullet rod  35  upward, and the bullet rod  35  climbs over the curved teeth  27   a  of the central axis groove portion  27 , such that shift feeling is generated at the lever body  20 . 
     That is, when the driver operates the lever button  13  to rotate the rotary motor  30 , the central axis gear  25 , which engages with the motor gear  31 , is rotated to move the lever body  20  upward. In this case, the curved teeth  27   a  of the central axis groove portion  27  are caught by the bullet rod  35  of the bullet unit  34 , such that the lever body  20  is moved upward in a stepwise manner with “click-rotation-click-rotation-click”. 
     Even when the driver holds the lever body  20  and intends to change the gear shift stage of the vehicle, the driver may surely recognize the change of the gear shift stage by the central axis groove portion  27  and the bullet unit  34 . 
     A solenoid coil  37  is mounted in the bullet unit  34 , and the solenoid coil  37  generates a magnetic field when electric power is applied to the solenoid coil  37 , and pushes the bullet rod  35  upward with strong force so as to allow the lever body  20  to be almost fixed. 
     The solenoid coil  37  serves to prevent the lever body  20  from being rotated by excessive force by the driver when the acceleration lever  40  is manipulated, or when the steering roller  60  is manipulated, to thereby prevent the change of the gear shift stage which is not desired by the driver. The solenoid coil  37  is manipulated by a separate button disposed in the vehicle, or automatically manipulated by the manipulation of the acceleration lever  40  or the steering roller  60 . 
     As illustrated in  FIG. 7A , the lever body  20  pops up as the rotary motor  30  is rotated by the operation of the lever button  13 , and is temporarily fixed as the rotary motor  30  is stopped by the operation of the stop button  14 , and in this case, the position of the gear shift magnet  32  embedded in the motor gear  31  is recognized as a P-stage by the gear shift control unit  33  (P-stage state). 
     As illustrated in  FIG. 7B , in a state in which the stop button  14  is operated, when the driver holds the lever body  20  and rotates the lever body  20  rearward (counterclockwise in the illustrated exemplary embodiment) by a length corresponding to one curved tooth  27   a  of the central axis groove portion  27  (that is, to such an extent that shift feeling is felt by the driver one time), the motor gear  31  is rotated forward (clockwise in the illustrated exemplary embodiment), such that the position of the gear shift magnet  32  is changed, and in this case, the gear shift control unit  33  recognizes the changed position of the gear shift magnet  32  as an R-stage (R-stage state). 
     As illustrated in  FIGS. 7C and 7D , when the driver rotates the lever body  20  rearward by a length corresponding to two or three curved teeth  27   a  in a similar manner, the gear shift stage of the vehicle may be changed to an N-stage (N-stage state) or to a D-stage (D-stage state). 
     As illustrated in  FIG. 7E , when the driver rotates the lever body  20  by a length corresponding to four or more curved teeth  27   a , the gear shift control unit  33  recognizes that the gear shift magnet  32  deviates from the D-stage state, such that the rotary motor  30  is operated. Based on the operation of the rotary motor  30 , the motor gear  31  is rotated counterclockwise, and rotates the lever body  20  clockwise, and the lever body  20  returns to the D-stage state. 
     As illustrated in  FIG. 7F , when the driver rotates the lever body  20  forward (clockwise), the gear shift control unit  33  recognizes that the gear shift magnet  32  deviates from the P-stage state, and the rotary motor  30  is operated. Based on the operation of the rotary motor  30 , the motor gear  31  is rotated clockwise, and rotates the lever body  20  counterclockwise, and the lever body  20  returns to the P-stage state. 
     That is, when the driver rotates the lever body  20  further forward than the P-stage state, or when the driver rotates the lever body  20  further rearward than the D-stage state, the lever body  20  may return to the P-stage state or the D-stage state by the rotary motor  30 . 
       FIG. 8  is an exploded view illustrating the acceleration lever, the first elastic unit  50 , the second elastic unit  70 , and the steering roller  60  according to the exemplary embodiment of the present invention,  FIG. 9A  is a perspective view illustrating an appearance of the first elastic unit  50  according to the exemplary embodiment of the present invention, and  FIG. 9B  is side views illustrating operational states of the acceleration lever  40  and the first elastic unit  50  according to the exemplary embodiment of the present invention. 
     As illustrated in  FIG. 8 , the first elastic unit  50  is formed as a flat spring having a lateral cross section having a parallelogram shape, and the second elastic unit  70  is formed as a flat spring having a cross section in a forward and rearward direction which has an elliptical shape, and the second elastic unit  70  may be coupled to an upper portion of the first elastic unit  50 . 
     specifically, when describing a coupling structure between the first elastic unit  50  and the second elastic unit  70 , extension portions  53  are first formed by extending a lower surface of the first elastic unit  50  to both sides, the extension portions  53  are inserted into and fixed to grooves in the lever body  20 , the second elastic unit  70  is coupled to the upper portion of the first elastic unit  50  by welding or riveting, and the second elastic unit  70  is inserted into a recessed groove  63 , which is formed in a lower portion of the steering roller  60 , and coupled to the steering roller  60 . 
     As illustrated in  FIGS. 9A and 9B , a slit  51  is formed to penetrate a lower surface of the first elastic unit  50 , and a contact portion  52 , which forms a cantilevered beam structure (a crossbeam having one end that is fixed, and the other end that is free) having three sides spaced apart from the first elastic unit  50 , and one side coupled to the first elastic unit  50 , and comes into contact with the acceleration lever  40 , is disposed in the slit  51 . 
     The contact portion  52  in the form of a cantilevered beam serves to prevent the second elastic unit  70  and the steering roller  60  into which the second elastic unit  70  is inserted from being affected by the manipulation of the acceleration lever  40 , and the manipulation of the acceleration lever  40  and the manipulation of the steering lever are performed independently. 
     That is, the contact portion  52  serves to prevent a steering effort of the steering roller  60  from being excessively raised due to deformation of the second elastic unit  70  caused by deformation of the first elastic unit  50  when the vehicle initially accelerates (in a low-speed state of the vehicle). 
     For reference, the first elastic unit  50  has a structure in which two sheets of flat springs are stacked, such that although one flat spring is first broken after the acceleration lever  40  is used over a long period of time or at the time of a vehicle accident, the other flat spring may consistently provide elastic restoring force. 
       FIG. 10A  is a side view illustrating an appearance in the lever body  20  when a rectilinear rod  81  according to the exemplary embodiment of the present invention is not moved forward,  FIG. 10B  is a side view illustrating an appearance in the lever body  20  when the rectilinear rod  81  according to the exemplary embodiment of the present invention is moved forward, and  FIG. 11  is a flow chart illustrating logic for controlling a movement amount of the rectilinear rod  81  according to whether a speed of a vehicle is increased or decreased, and whether a lane departure warning system is operated. 
     As illustrated in  FIGS. 10A and 10B , a rectilinear motor  80 , which has the rectilinear rod  81  that is movable forward and rearward, is disposed at a rear side of the first elastic unit  50  that is formed as a parallelogram-shaped flat spring. 
     The rectilinear motor  80  moves the rectilinear rod  81  forward to push one end (a rear end in the illustrated exemplary embodiment) of the first elastic unit  50 , and thereby, the shape of the lateral cross section of the first elastic unit  50  is deformed, and the shape of the second elastic unit  70  is also deformed, such that the steering effort of the steering roller  60  is changed. 
     Specifically, the shape of the lateral cross section of the first elastic unit  50  is gradually changed from the parallelogram shape to a rectangular shape as the rectilinear rod  81  is moved forward, such that a height of the first elastic unit  50  is increased, and the second elastic unit  70  is pressed and flattened by the first elastic unit  50 , thereby increasing a spring constant. 
     In this case, the spring constant of the first elastic unit  50  may be greater than the spring constant of the second elastic unit  70 , and thereby, the second elastic unit  70  may also be deformed in accordance with the deformation of the first elastic unit  50 . 
     As illustrated in  FIG. 11 , the gear shift state of the lever body  20  is first confirmed (S 100 ), and thereafter, whether the gear shift state is a driving stage or a reversing stage (D-stage or R-stage) is confirmed (S 200 ). When the gear shift state is not the driving stage or the reversing stage (the gear shift stage is the P-stage or the N-stage), a stopped state of the vehicle is maintained (S 210 ), and when the gear shift state is the driving stage or the reversing stage, whether the speed of the vehicle is increased or decreased is confirmed (S 300 ). 
     The rectilinear rod  81  is not moved but remains at an initial position as it is (S 310 ) when the speed of the vehicle is “0”, an amount of forward movement of the rectilinear rod  81  is increased as the speed of the vehicle is increased (S 320 ), the amount of forward movement of the rectilinear rod  81  is decreased as the speed of the vehicle is decreased (S 340 ), and the amount of forward movement of the rectilinear rod  81  is maintained when the speed of the vehicle is maintained without being increased or decreased (S 330 ). 
     The rectilinear motor  80  and the rectilinear rod  81  may be connected with the lane departure warning system of the vehicle so as to improve safety of the vehicle (S 400 ). 
     The lane departure warning system of the vehicle refers to a system that assists the driver in driving the vehicle without deviating from the lane when the driver abruptly changes the lane due to driving while drowsy, or when there is a risk of collision due to changing a lane. 
     When a safety control signal is generated by the lane departure warning system, the rectilinear motor  80  moves the rectilinear rod  81  maximally forward, and the spring constant of the first elastic unit  50  is maximally increased, such that the steering effort of the steering roller  60  is maximized, and the steering roller  60  is hardly rotated (S 420 ). When a safety control signal is not generated by the lane departure warning system, the amount of forward movement of the rectilinear rod  81  is maintained as it is (S 410 ). 
     Therefore, the present invention may reduce production costs and weight of the vehicle by easily implementing safety control logic for the vehicle using a simple structure that uses the rectilinear motor  80  and the rectilinear rod  81 . 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.