Patent Publication Number: US-11378995-B2

Title: Ambient light device for dial type shifting apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean Patent Application No. 10-2019-0145671, filed on Nov. 14, 2019, which application is hereby incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an ambient light device for a dial type shifting apparatus. 
     BACKGROUND 
     In general, a vehicle equipped with an automatic transmission controls the hydraulic pressure within a shift range set according to the running speed of the vehicle so that a shift gear of a target shift stage range may be automatically operated. 
     The automatic transmission generates a gear ratio by using a hydraulic circuit, a planetary gear, and friction elements to perform the shift, and control of these components is handled by a Transmission Control Unit (TCU). 
     A Shift By Wire (hereinafter referred to as SBW) system, which is an electronic transmission system for a vehicle, is an electronic transmission system having no mechanical connection structure such as a cable between a transmission and a shifting apparatus (a lever, a button, a dial) unlike a conventional mechanical transmission system, and is a system in which if a signal generated at the operation of the electronic shifting apparatus (the shift lever, the button or the dial) is delivered to the Transmission Control Unit (TCU), a transmission actuator (a shift cable motor, a select cable motor) is operated by an electronic signal instructed by the TCU, and the hydraulic pressure is applied or blocked to the hydraulic circuit for each shift stage by an operation of the transmission actuator, thereby electronically performing a shift control. 
     Therefore, the SBW-based automatic transmission may deliver the driver&#39;s shift will to the TCU as an electric signal through a simple operation of the electronic shifting apparatus (the shift lever, the button or the dial), thereby proceeding the shifting to a drive (D) stage, a reverse (R) stage, a Null stage (a Nd stage, a Nr stage), or the like more easily, and also enable the miniaturization of the shifting apparatus, thereby securing a wide space between a driver seat and a passenger seat. 
     A method of performing the shifting in the electronic transmission system is largely classified into a lever type using a lever, a button type using a button, and a dial type using a dial. 
     The dial type shifting apparatus is a configuration of generating a shift signal as the shift dial corresponding to the rotating component rotates with respect to the housing corresponding to the fixed component, and has the disadvantage in that it is difficult to implement ambient light in a dial type shifting apparatus having a shift dial operated to be rotated. 
     Ambient light is a decorative mood lamp that emits a soft light instead of the direct light of a light source at the necessary portion of a vehicle interior at night, and if the light from the light source comes directly into the driver&#39;s eyes, the fatigue of the driver&#39;s eyes is increased when driving at night, which reduces concentration and interferes with safe driving, such that in order to prevent this, the ambient light is implemented at the necessary portion of the vehicle interior instead of the direct light of the light source. 
     If the ambient light is implemented in the shifting apparatus operated by the driver, the driver may visually secure the shifting when the driver performs the shifting at night, but it is generally difficult to implement the ambient light in the dial type shifting apparatus having the shift dial rotated by the driver&#39;s operation. 
     Further, even if the ambient light is implemented in the dial type shifting apparatus having the shift dial operated to be rotated, as a structure in which a component having light for covering the light of the light source mostly covers 90% or more of the light of the light source, it is not possible to properly implement the ambient light due to the excessive light loss. 
     The foregoing explained as the background is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. 
     SUMMARY 
     The present disclosure relates to an ambient light device for a dial type shifting apparatus. Particular embodiments relate to an ambient light device for a dial type shifting apparatus capable of implementing ambient light in a shift dial rotated by a driver&#39;s operation. 
     An embodiment of the present disclosure provides an ambient light device for a dial type shifting apparatus that is a configuration that is configured to fix a printed circuit board (PCB), a light source, and a light guide to a main housing corresponding to a fixed component, and has a reflector and a lighting window for reflecting the light of the light source to the shift dial that is a rotating component rotated by the driver&#39;s operation, thereby implementing ambient light in a dial type shifting apparatus having a shift dial rotated by the driver&#39;s operation, and through this configuration, may implement the ambient light without the light loss of the light source as much as possible, thereby enhancing merchantability. 
     An ambient light device for a dial type shifting apparatus according to embodiments of the present disclosure includes a PCB coupled to a main housing, a light source fixed to the PCB, a light guide coupled to the main housing and for delivering light of the light source, and a light emitting mechanism provided in a shift dial coupled rotatably with respect to the main housing and for reflecting the light of the light source delivered through the light guide to emit it to the outside of the shift dial in an ambient light form. 
     It is configured so that a boss part protruded upward is formed in the main housing, the light guide is installed to be fitted into the outside of the boss part, the PCB and the light source are positioned below the light guide, and the light emitting mechanism is positioned above the light guide. 
     The boss part protruded upward is formed in the main housing, and the light guide includes a cylindrical part installed to be fitted into the outside of the boss part. A leg part protruded downward from the cylindrical part to face the light source is fixed to the PCB. 
     An optic is formed on the upper surface of the cylindrical part to scatter the light of the light source. 
     The shift dial includes a lower dial coupled rotatably with respect to the main housing, and an upper dial coupled with the lower dial, the upper surface of the cylindrical part of the light guide faces the lower dial, and a portion facing the upper surface of the cylindrical part in the lower dial is configured as a light transmission part through which light may pass. 
     The light emitting mechanism includes a reflector coupled to the upper portion of the lower dial to be positioned above the light transmission part, and a lighting window coupled with the upper dial to cover the opened upper portion of the upper dial. The light of the light source having passed through the light transmission part and then reflected from the reflector is reflected again through the surface of the lower dial and the inside surface of the upper dial and then emitted to the outside through the lighting window, thereby implementing ambient light. 
     A pattern layer for implementing a pattern of a specific shape by using the light reflected from the reflector is formed on the surface of the lower dial. 
     The lower surface of the reflector facing the light transmission part is formed of an inclined surface to reflect the light of the light source to the surface of the lower dial. 
     According to an ambient light device for the dial type shifting apparatus according to embodiments of the present disclosure, a light source is coupled to a main housing corresponding to a fixed component, a reflector is coupled to a shift dial that is a rotating component rotating with respect to the main housing, and the light of the light source is reflected from the reflector and then emitted to the outside of the shift dial, thereby implementing ambient light. 
     A light guide for delivering the light of the light source to the reflector is positioned between the light source and the reflector, and the light guide is coupled to be fixed to the main housing that is a fixed component. 
     An embodiment according to the present disclosure is a configuration that is configured to fix the PCB, the light source, and the light guide to the main housing corresponding to the fixed component, and has the reflector and the lighting window for reflecting the light of the light source to the shift dial that is the rotating component rotated by the driver&#39;s operation, thereby implementing the ambient light in the dial type shifting apparatus having the shift dial rotated by the driver&#39;s operation, and through this configuration, may faithfully implement the ambient light while minimizing the light loss of the light source in the dial type shifting apparatus having the shift dial rotated by the driver&#39;s operation, thereby enhancing merchantability. 
     Further, an embodiment of the present disclosure is a configuration in which the bearing has been installed between the boss part of the main housing and the rotator coupled with the shift dial, and may prevent the direct contact between the boss part corresponding to the fixed component and the shift dial and the rotator corresponding to the rotating components to prevent generation of the friction force through the bearing at the rotation operation of the shift dial, thereby achieving wear prevention and noise prevention due to the friction force to enhance the durability, and furthermore, eliminating the occurrence of heterogeneous feeling due to the friction, thereby enhancing the operation feeling. 
     Further, embodiments of the present disclosure may eliminate generation of the friction force between the boss part corresponding to the fixed component and the shift dial and the rotator corresponding to the rotating components by using the bearing to eliminate the stuck phenomenon of the shift dial rotating from the Null stage to the D stage or from the Null stage to the R stage, thereby improving the quality. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective diagram of a dial type shifting apparatus for an electronic transmission system according to an embodiment of the present disclosure; 
         FIGS. 2 and 3  are a coupling perspective diagram and a coupled state cross-sectional diagram of  FIG. 1 , respectively; 
         FIG. 4  is an enlarged diagram of a portion on which a bearing has been installed in  FIG. 3 ; 
         FIG. 5  is an enlarged diagram of a portion on which a bearing holder has been installed according to an embodiment of the present disclosure; 
         FIG. 6  is an enlarged diagram of a portion on which a dial flange has been formed according to an embodiment of the present disclosure; 
         FIG. 7  is a diagram for explaining a configuration of providing an operation feeling and a return force of a shift dial according to an embodiment of the present disclosure; 
         FIG. 8  is an exploded perspective diagram of an ambient light device according to an embodiment of the present disclosure; 
         FIG. 9  is a coupled state cross-sectional diagram of  FIG. 8 ; and 
         FIG. 10  is a plane diagram of a dial type shifting apparatus in which ambient light has been illuminated according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Hereinafter, an ambient light device for a dial type shifting apparatus according to a preferred embodiment of the present disclosure will be described with reference to the accompanying drawings. 
     A dial type shifting apparatus for an electronic transmission system according to an embodiment of the present disclosure includes a main housing  100  having a boss part  110  protruded upward as illustrated in  FIGS. 1 to 10 . 
     The main housing  100  is installed to be fixed to a vehicle body (a console, a center fascia, or the like) of the side portion of a driver seat, and the main housing  100  is formed integrally with the boss part  110  formed in a cylindrical shape and protruded upward. 
     The boss part  110  includes a primary boss  111  of a cylindrical shape having a predetermined diameter, and a secondary boss  112  formed in a cylindrical shape having a larger diameter than that of the primary boss  111  and positioned outside the primary boss  111 . 
     A bearing  200  is installed to be fitted into the outside of the boss part  110 , a rotator  300  is installed to be fitted into the outside of the bearing  200 , and the rotator  300  is coupled with a shift dial  400  rotated by a driver&#39;s hand&#39;s operation. 
     The bearing  200  includes an inner ring  210  forcibly press-fitted into the outside of the secondary boss  112  to be coupled integrally with the secondary boss  112 , an outer ring  220  forcibly press-fitted into the inside of the rotator  300  to be coupled integrally with the rotator  300 , and a plurality of balls  230  positioned between the inner ring  210  and the outer ring  220 . 
     The rotator  300  is coupled to the lower portion of the shift dial  400  to extend downward from the shift dial  400  to be formed integrally with the shift dial  400 , the rotator  300  and the bearing  200  become a structure that is covered by the shift dial  400  not to be exposed outward, and the shift dial  400  and the rotator  300  are rotated together at the driver&#39;s operation. 
     The bearing  200  is installed to be inserted into a gap between the secondary boss  112  and the rotator  300 , and is installed so that the bearing  200  is fitted into the outside of the secondary boss  112 , and the rotator  300  is fitted into the outside of the bearing  200 . 
     That is, the inner ring  210  of the bearing  200  is coupled by being fitted into the outside of the secondary boss  112  in a forcibly press-fitting method, and the rotator  300  coupled with the shift dial  400  is coupled by being fitted into the outside of the outer ring  220  of the bearing  200  in the forcibly press-fitting method. 
     At this time, bearing support projections  112   a ,  310  in which the lower end of the bearing  200  has been seated are formed at the outside of the secondary boss  112  and the inside of the rotator  300 , respectively, and the bearing support projections  112   a ,  310  serve to support the lower end of the bearing  200  to restrain the downward movement of the bearing  200 . 
     The bearing support projection  112   a  formed at the secondary boss  112  supports the lower end of the inner ring  210  of the bearing  200 , and the bearing support projection  310  formed at the rotator  300  supports the lower end of the outer ring  220  of the bearing  200 . 
     Therefore, if the driver rotates the shift dial  400 , the rotator  300  rotates together with the shift dial  400 , and the outer ring  220  of the bearing  200  rotates together with the rotator  300 , and at this time, the secondary boss  112  of the main housing  100  and the inner ring  210  of the bearing  200  coupled with the secondary boss  112  become fixed components that do not rotate. 
     As described above, an embodiment according to the present disclosure is a configuration in which the bearing  200  has been installed between the boss part  110  of the main housing  100  and the rotator  300  coupled with the shift dial  400 , and may prevent the direct contact between the boss part no corresponding to the fixed component and the shift dial  400  and the rotator  300  corresponding to the rotating components to prevent generation of the friction force through the bearing  200  at the rotation operation of the shift dial  400 , thereby achieving wear prevention and noise prevention due to the friction force to enhance the durability, and furthermore, may eliminate the occurrence of the heterogeneous feeling due to the friction, thereby enhancing the operation feeling. 
     Further, embodiments of the present disclosure may eliminate generation of the friction force between the boss part  110  corresponding to the fixed component and the shift dial  400  and the rotator  300  corresponding to the rotating components by using the bearing  200  to eliminate the stuck phenomenon of the shift dial  400  rotating from the Null stage to the D stage or from the Null stage to the R stage, thereby improving the quality. 
     An embodiment according to the present disclosure further has a configuration of restraining the upward movement of the bearing  200  by using a bearing holder  500 , thereby preventing the upward separation of the bearing  200 . 
     The bearing holder  500  is positioned in the shift dial  400  and fitted into a gap between the primary boss in and the secondary boss  112  to be installed to contact the upper surface of the bearing  200 . 
     Describing it in more detail, a light guide  600  is installed to be fitted into the outside of the primary boss  111  to be coupled with the primary boss  111 , a cylindrical holder coupling part  510  constituting the bearing holder  500  is fitted into a gap between the light guide  600  and the secondary boss  112 , and the upper and lower ends of the holder coupling part  510  are formed in the cross section of a triangular protrusion, respectively, such that an upper triangular protrusion cross section  511  is coupled to the upper side of the light guide  600  in a latching structure, and a lower triangular protrusion cross section  512  is coupled to a latching projection  112   b  formed inside the secondary boss  112  in a latching structure. 
     A bearing pressing part  520  constituting the bearing holder  500  is formed to be protruded outward from the holder coupling part  510 , and presses the upper surface of the inner ring  210  of the bearing  200  when the holder coupling part  510  is installed to be inserted into the gap between the light guide  600  and the secondary boss  112 , such that the bearing  200  is pressed by the bearing holder  500 , thereby preventing the upward movement and separation. 
     The shift dial  400  largely includes a lower dial  410  coupled with the rotator  300  and rotating with respect to the main housing  100 , and an upper dial  420  coupled with the lower dial  410  and operated by a driver. 
     Although a lighting window  430  may be included in the shift dial  400 , the lighting window  430  is described as a component of a light emitting mechanism for implementing ambient light in another embodiment of the present disclosure. 
     Describing the inside surface of the shift dial  400  in more detail in an embodiment according to the present disclosure, the lower inside surface of the lower dial  410  is formed integrally with a dial flange  440  protruded toward the bearing  200  installed between the secondary boss  112  and the rotator  300 . 
     The lower end of the dial flange  440  is configured to be slightly spaced apart from the upper side of the bearing  200 , and if the bearing  200  is moved upward by an external force, the upper surface of the bearing  200  contacts the lower end of the dial flange  440 , and therefore, the dial flange  440  serves to prevent the upward separation of the bearing  200  together with the bearing holder  500 . 
     The dial type shifting apparatus according to embodiments of the present disclosure further includes a device for implementing ambient light. 
     That is, an ambient light device for the dial type shifting apparatus according to the present disclosure further includes a Printed Circuit Board (PCB)  710  coupled to be fixed to the main housing  100 , a plurality of light sources  720  fixed to the PCB  710 , the light guide  600  coupled to the main housing  100  and for delivering the light of the light source  720 , and a light emitting mechanism provided in the shift dial  400  coupled rotatably with respect to the main housing  100  and for reflecting the light of the light source  720  delivered through the light guide  600  to emit it to the outside of the shift dial  400  in an ambient light form. 
     D stage, R stage, and Null stage signals generated by the rotation operation of the shift dial  400  and a P stage signal generated by the pressing operation of a P stage button  740  are delivered to the Transmission Control Unit (TCU) through the PCB  710 , a transmission actuator is operated by a signal commanded from the Transmission Control Unit, and hydraulic pressure is applied or blocked to a hydraulic circuit for each shift stage of the transmission by an operation of the transmission actuator, thereby electronically performing a shift control. 
     The light source  720  installed to the PCB  710  is an LED light source, and may implement the ambient light (the mood light) when the light source  720  is turned on according to the driver&#39;s switch operation. 
     Describing a configuration for implementing the ambient light in more detail, it is configured so that the light guide  600  is installed to be fitted into the outside of the primary boss  111  formed in the main housing  100  to be coupled with the primary boss  111 , the PCB  710  and the light source  720  are positioned below the light guide  600 , and the light emitting mechanism is positioned above the light guide  600 . 
     The light guide  600  is a component for delivering the light generated from the light source  720  toward a reflector  730  to be described later, and includes a cylindrical part  610  installed to be fitted into the outside of the primary boss  111 , and a plurality of leg parts  620  protruded downward from the cylindrical part  610  to face the light source  720  fixed to the PCB  710 . 
     The leg part  620  is configured to be formed in the same number as the light source  720  so that the leg part  620  and the light source  720  are matched one by one, respectively. 
     Further, an optic  630  for scattering light to spread the light of the light source  720  evenly is formed on the entire upper surface of the cylindrical part  610  constituting the light guide  600 . 
     It is possible to implement the scattered reflection of the light by the optic  630 . 
     As the light guide  600  is positioned below the lower dial  410  constituting the shift dial  400 , the optic  630  formed on the upper surface of the cylindrical part  610  of the light guide  600  is configured to face the lower dial  410 , such that a portion facing the optic  630  formed on the upper surface of the cylindrical part  610  in the lower dial  410  is configured as a light transmission part  411  through which light may pass. 
     The light transmission part  411  of the lower dial  410  may be an air layer, or may also be formed of a transparent window through which light may pass. 
     The light emitting mechanism includes the reflector  730  installed to be fitted into the upper side of the lower dial  410  to be positioned above the light transmission part  411 , and the lighting window  430  coupled with the upper dial  420  to cover the opened upper portion of the upper dial  420 . 
     The lighting window  430  may be formed of a transparent window or a translucent window through which light may pass. 
     If the LED light source  720  is turned on through a control of the PCB  710  by the driver&#39;s switch operation, the light generated from the light source  720  moves through the light guide  600  and then passes through the light transmission part  411  of the lower dial  410 , the light having passed through the light transmission part  411  of the lower dial  410  is reflected through the reflector  730  coupled to the upper side of the lower dial  410 , and the light of the light source  720  reflected from the reflector  730  is reflected again through the surface of the lower dial  410  and the inside surface of the upper dial  420  and then is emitted to the outside of the shift dial  400  through the lighting window  430 , thereby implementing the ambient light. 
     Therefore, an embodiment according to the present disclosure is a configuration that may sufficiently implement the ambient light while minimizing the light loss of the light source  720  in the dial type shifting apparatus having the shift dial  400  rotated by the driver&#39;s operation, and through this configuration, may enhance the merchantability. 
     That is, an embodiment of the present disclosure is a configuration in which the PCB  710 , the light source  720 , and the light guide  600  are configured to be fixed to the main housing  100  corresponding to the fixed component, and has the reflector  730  and the lighting window  430  for reflecting the light of the light source  720  to the shift dial  400  that is the rotating component rotated by the driver&#39;s operation, thereby implementing the ambient light and through this configuration, may faithfully implement the ambient light while minimizing the light loss of the light source  720  in the dial type shifting apparatus having the shift dial  400  rotated by the driver&#39;s operation. 
     According to an embodiment of the present disclosure, since a pattern layer  450  that may implement a pattern of a specific shape by using the light reflected from the reflector  730  is formed on the surface of the lower dial  410 , the light of the light source  720  reflected from the reflector  730  may be irradiated to the pattern layer  450  formed on the surface of the lower dial  410 , and the light irradiated to the pattern layer  450  may be exposed to the outside through the lighting window  430  constituting the shift dial  400 , thereby implementing the ambient light. 
     For example, it is possible to implement the ambient light (L 1 ) giving the feeling that the light spreads radially through the pattern layer  450  as in  FIG. 10 , and to implement the ambient light of various patterns according to the shape of the pattern layer  450 . 
     Further, according to an embodiment of the present disclosure, the lower surface of the reflector  730  facing the light transmission part  411  in the reflector  730  is preferably formed of the surface of the lower dial  410 , that is, an inclined surface  731  in order to evenly reflect the light of the light source  720  to the pattern layer  450 , such that the angle of the inclined surface  731  is formed at the inclination angle of the shape in which the angle between the pattern layers  450  gradually increases radially toward the outside. 
     Further, the dial type shifting apparatus according to embodiments of the present disclosure further includes a configuration for providing the operation feeling (the shift feeling) when the driver operates the rotation of the shift dial  400 , and returning the shift dial  400  to the return position when releasing the operating force from the rotated shift dial  400 . 
     That is, an operation feeling generation part  810  is formed integrally in the rotator  300 , and a groove  811  recessed in an arc shape is formed in the longitudinal middle part of the operation feeling generation part  810 . 
     The operation feeling generation part  810  is formed to expand in the radial direction of the rotator  300  and to have both ends extending along the circumferential direction. 
     Further, one end of a leaf spring assembly  820  is coupled to be fixed to the main housing  100 , a roller  830  is rotatably coupled to the other end of the leaf spring assembly  820 , and the roller  830  is inserted into the groove  811  or out of the groove  811  at the rotation of the shift dial  400  to contact the side surface of the operation feeling generation part  810 . 
     As illustrated in  FIG. 7 , when the roller  830  is positioned in the groove  811  of the operation feeling generation part  810 , the shift stage of the vehicle maintains the Null stage state. 
     If the driver rotates the shift dial  400  clockwise (an arrow R 1 ) in a state where the shift stage is in the Null stage, the roller  830  in the groove  811  of the operation feeling generation part  810  is out of the groove  811  by the rotation of the rotator  300  to contact the surface of the operation feeling generation part  810 , and at this time, the leaf spring assembly  820  accumulates the elastic force while being bent to the outside (an arrow M 1 ), and the shift stage is changed into the Nd stage or the D stage. 
     Further, if the driver releases the operating force from the shift dial  400  rotated to the Nd stage or the D stage, the leaf spring assembly  820  bent to the outside (an arrow M 1 ) exerts a force of moving in the opposite direction to the arrow M 1  by the restoring force, the roller  830 , which has been out of the groove  811  by the restoring force of the leaf spring assembly  820  to contact the surface of the operation feeling generation part  810 , performs an operation that is inserted into the groove  811  again, and through this operation of the roller  830 , the shift dial  400  positioned at the Nd stage or the D stage is rotated counterclockwise (an arrow R 2 ) through the restoring force of the leaf spring assembly  820  to return to the Null stage that is the return position. 
     Further, since the rotation from the Null stage to the Nr stage or the R stage, and the return operation from the Nr stage or the R stage to the Null stage is the same as described above, detailed description thereof will be omitted. 
     As described above, the dial type shifting apparatus according to embodiments of the present disclosure is a configuration in which the bearing  200  has been installed between the boss part  110  of the main housing  100  and the rotator  300  coupled with the shift dial  400 , and may prevent the direct contact between the boss part  110  corresponding to the fixed component and the shift dial  400  and the rotator  300  corresponding to the rotating components to prevent generation of the friction force through the bearing  200  at the rotation operation of the shift dial  400 , thereby achieving wear prevention and noise prevention due to the friction force to enhance the durability, and furthermore, eliminating the occurrence of the heterogeneous feeling due to the friction, thereby enhancing the operation feeling. 
     Further, the present disclosure may eliminate generation of the friction force between the boss part  110  corresponding to the fixed component and the shift dial  400  and the rotator  300  corresponding to the rotating components by using the bearing  200  to eliminate the stuck phenomenon of the shift dial  400  rotating from the Null stage to the D stage or from the Null stage to the R stage, thereby improving the quality. 
     Further, an embodiment of the present disclosure is a configuration that is configured to fix the PCB  710 , the light source  720 , and the light guide  600  to the main housing  100  corresponding to the fixed component, and has the reflector  730  and the lighting window  430  for reflecting the light of the light source  720  to the shift dial  400  that is the rotating component rotated by the driver&#39;s operation, thereby implementing the ambient light in the dial type shifting apparatus having the shift dial  400  rotated by the driver&#39;s operation, and through this configuration, may faithfully implement the ambient light while minimizing the light loss of the light source  720  in the dial type shifting apparatus having the shift dial  400  rotated by the driver&#39;s operation, thereby enhancing the merchantability. 
     While the present disclosure has illustrated and described specific embodiments, it will be apparent to those skilled in the art that the present disclosure may be variously improved and modified without departing from the spirit of the present disclosure provided by the following claims.