Patent Publication Number: US-2021170842-A1

Title: Vehicle Door Check Mechanism and Vehicle Door Opening and Closing Apparatus Having the Same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2019-0160950, filed on Dec. 5, 2019, in the Korean Intellectual Property Office, which application is hereby incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a vehicle door check mechanism and a vehicle door opening and closing apparatus having the same. 
     BACKGROUND 
     Vehicles have door apertures for ingress and egress of vehicle passengers to and from a passenger compartment. A vehicle door is closed to block the door aperture and is opened to enable ingress and egress of passengers to and from the passenger compartment through the door aperture. 
     Vehicle doors are divided into swing doors and sliding doors. The swing door is opened and closed by swinging around a hinge mounted between the swing door and the vehicle body. The sliding door is opened and closed by sliding a roller mounted on the sliding door along a rail mounted on the vehicle body. 
     The swing door is very easy to open and close, thereby enabling quick ingress and egress of passengers. However, when the swing door is opened, a space for ingress and egress is relatively small. When the vehicle is located in a narrow space, a swing trajectory of the door is not secured, which makes the opening and closing operation thereof difficult. 
     The sliding door is very easy to open and close even when the vehicle is located in a narrow space. When the sliding door is opened, a space for ingress and egress is relatively large. However, the sliding door requires relatively more force and time to open and close, which hinders quick ingress and egress of passengers. 
     According to the related art, as a vehicle door is operated by a single opening and closing method, it may be difficult to adequately respond to the needs of customers seeking ease of use, diversity, and novelty. 
     Meanwhile, the swing door includes a vehicle door check mechanism such as a check strap allowing the swing door to be held and stopped at predetermined intervals when the swing door is opened. The vehicle door check mechanism may be disposed between the vehicle door and the vehicle body. However, as the vehicle door check mechanism according to the related art has a straight structure, it may be difficult to install the vehicle door check mechanism when a space between the swing door and the vehicle body is narrow as in a pillarless vehicle. In addition, it may be difficult to reliably ensure a check operation of the vehicle door check mechanism. 
     The above information described in this background section is provided to assist in understanding the background of the inventive concept, and may include any technical concept which is not considered as the prior art that is already known to those skilled in the art. 
     SUMMARY 
     Embodiments of the present disclosure solves problems occurring in the prior art while advantages achieved by the prior art are maintained intact. 
     The present disclosure relates to a vehicle door check mechanism and a vehicle door opening and closing apparatus having the same. Particular embodiments relate to a vehicle door check mechanism that can be applied to vehicles of various structures and a vehicle door opening and closing apparatus having the same. 
     An embodiment of the present disclosure provides a vehicle door check mechanism having a curved structure corresponding to a swing trajectory of a vehicle door, thereby being applied to vehicles of various structures, and a vehicle door opening and closing apparatus having the same. 
     According to an embodiment of the present disclosure, a vehicle door check mechanism may include a strap body mounted on a portion of a vehicle door adjacent to a rotation axis of the vehicle door, and configured to move with the vehicle door as the vehicle door swings around the rotation axis, and a hold unit configured to allow the strap body to be held at regular intervals, wherein the strap body may be curved to have a predetermined curvature radius. 
     A center of the curvature radius may be located on the rotation axis of the vehicle door, and the strap body may have a fixed end which is fixed to the vehicle door, and a free end which is spaced apart from the vehicle door. 
     The hold unit may include a first hold member and a second hold member disposed on both sides of the strap body. The first hold member may have a plurality of recesses spaced apart from each other in a longitudinal direction of the first hold member, and the second hold member may have a plurality of recesses spaced apart from each other in a longitudinal direction of the second hold member. The strap body may have a first projection selectively received in any one of the recesses of the first hold member, and a second projection selectively received in any one of the recesses of the second hold member. 
     The first hold member may have a first cushion material contacting the first projection, and the second hold member may have a second cushion material contacting the second projection. 
     The hold unit may include a hold member located below the strap body. The strap body may have a roller rotatably mounted on the free end. The hold member may have a plurality of recesses, the recesses may be spaced apart from each other in a longitudinal direction of the hold member, and the roller may be selectively received in any one of the recesses. 
     The strap body may have a plurality of recesses facing the rotation axis of the vehicle door, and the hold unit may include a cam member having a projection selectively received in any one of the recesses of the strap body. 
     The cam member may allow the projection to be biased toward the recesses by a biasing element. 
     The hold unit may further include a guide roller guiding a movement of the strap body. The guide roller may be disposed to face the cam member. 
     The vehicle door check mechanism may further include a guide member guiding a movement of the strap body. 
     The strap body may have a plurality of inner peripheral recesses facing the rotation axis of the vehicle door, and a plurality of outer peripheral recesses opposing the plurality of inner peripheral recesses. The hold unit may include a first ball selectively received in any one of the outer peripheral recesses, and a second ball selectively received in any one of the inner peripheral recesses. 
     The vehicle door check mechanism may further include a strap housing guiding a movement of the strap body, and the first ball and the second ball may be mounted in the strap housing. 
     The first ball may be supported by a first ball support, and the first ball support may be elastically supported by a first elastic member. The second ball may be supported by a second ball support, and the second ball support may be elastically supported by a second elastic member. 
     According to another embodiment of the present disclosure, a vehicle door opening and closing apparatus may include a vehicle door, a rail mounted on a vehicle body, a roller unit mounted on the vehicle door, and allowing the vehicle door to open and close in one mode selected from a sliding mode, in which the vehicle door slides along the rail, and a swing mode, in which the vehicle door swings in a predetermined position of the rail, and a vehicle door check mechanism disposed between the vehicle door and the roller unit. The vehicle door check mechanism may include a strap body mounted on a portion of a vehicle door adjacent to a rotation axis of the vehicle door, and moving with the vehicle door as the vehicle door swings around the rotation axis, and a hold unit allowing the strap body to be held at regular intervals. The strap body may be curved to have a predetermined curvature radius. 
     The roller unit may include a hold lock, and the roller unit may be releasably held in the predetermined position of the rail by the hold lock. The vehicle door may swing around the rotation axis when the roller unit is held in the predetermined position of the rail by the hold lock, and the vehicle door may slide along the rail when the roller unit is released by the hold lock. 
     The roller unit may include a roller bracket having a roller rolling along the rail, and a body connecting the roller bracket and the vehicle door, and the hold unit may be mounted on the body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of embodiments of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure, which is mounted on a rear door of a vehicle; 
         FIG. 2  illustrates a selector adjacent to an outside handle of a vehicle, an actuator connected to the selector, and hold locks; 
         FIG. 3  illustrates a state in which the door of  FIG. 1  is opened in a sliding mode; 
         FIG. 4  illustrates a state in which the door of  FIG. 1  is opened in a swing mode; 
         FIG. 5  illustrates an operation in which an upper roller unit and a lower roller unit move along an upper rail and a lower rail in a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure; 
         FIG. 6  illustrates an upper roller unit and a lower roller unit in a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure; 
         FIG. 7  illustrates an operation in which a vehicle door is opened and closed in a swing mode by an upper roller unit and a lower roller unit of a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure; 
         FIG. 8  illustrates an upper roller unit and a lower roller unit in a vehicle door opening and closing apparatus according to another exemplary embodiment of the present disclosure; 
         FIG. 9  illustrates an operation in which a vehicle door is opened and closed in a swing mode by an upper roller unit and a lower roller unit of a vehicle door opening and closing apparatus according to another exemplary embodiment of the present disclosure; 
         FIG. 10A  illustrates a perspective view of an upper hold lock and a lower hold lock; 
         FIG. 10B  illustrates a state in which an upper hold lock and a lower hold lock hold corresponding strikers; 
         FIG. 10C  illustrates a state in which an upper hold lock and a lower hold lock release corresponding strikers; 
         FIG. 10D  illustrates a state in which an upper hold lock and a lower hold lock are enabled to receive corresponding strikers; 
         FIG. 11  illustrates a main latch mounted on a vehicle door and a main striker; 
         FIG. 12  illustrates a perspective view of a center rail in a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure; 
         FIG. 13  illustrates a cross-sectional view of a swing guide of a center rail; 
         FIG. 14  illustrates a cross-sectional view of a sliding guide of a center rail; 
         FIG. 15  illustrates a structure in which a center roller unit is held in a swing guide of a center rail; 
         FIG. 16  illustrates an operation in which a center roller unit is released from a swing guide of a center rail; 
         FIG. 17  illustrates a vehicle door check mechanism mounted on a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure; 
         FIG. 18  illustrates a state of a strap body of the vehicle door check mechanism when the vehicle door illustrated in  FIG. 17  is opened in a swing mode; 
         FIG. 19  illustrates a perspective view of a vehicle door check mechanism according to an exemplary embodiment of the present disclosure; 
         FIG. 20  illustrates a state of the strap body illustrated in  FIG. 19  when a vehicle door is closed in a swing mode; 
         FIG. 21  illustrates a state of the strap body illustrated in  FIG. 19  when a vehicle door is opened in a swing mode; 
         FIG. 22  illustrates a perspective view of a vehicle door check mechanism according to another exemplary embodiment of the present disclosure; 
         FIG. 23  illustrates a perspective view of the strap body illustrated in  FIG. 22  when a vehicle door is opened in a swing mode; 
         FIG. 24  illustrates a perspective view of the strap body illustrated in  FIG. 22  which has moved on a hold member when a vehicle door is closed in a swing mode; 
         FIG. 25  illustrates a perspective view of the hold member of the vehicle door check mechanism illustrated in  FIG. 22 ; 
         FIG. 26  illustrates a vehicle door check mechanism according to another exemplary embodiment of the present disclosure; 
         FIG. 27  illustrates a vehicle door check mechanism according to another exemplary embodiment of the present disclosure; 
         FIG. 28  illustrates an enlarged view of the vehicle door check mechanism illustrated in  FIG. 27 ; 
         FIG. 29  illustrates a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure, which is applied to a front door of a vehicle, in a state in which the front door is opened in a sliding mode; 
         FIG. 30  illustrates a state in which the front door of  FIG. 29  is opened in a swing mode; 
         FIG. 31  illustrates a vehicle door opening and closing apparatus according to an exemplary embodiment of the present disclosure, which is applied to a front door and a rear door of a vehicle, in a state in which the front door and the rear door are opened in a sliding mode; and 
         FIG. 32  illustrates a state in which the front door and the rear door of  FIG. 31  are opened in a swing mode. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals will be used throughout to designate the same or equivalent elements. In addition, a detailed description of well-known techniques associated with the present disclosure will be omitted in order not to unnecessarily obscure the gist of the present disclosure. 
     Terms such as first, second, A, B, (a), and (b) may be used to describe the elements in exemplary embodiments of the present disclosure. These terms are only used to distinguish one element from another element, and the intrinsic features, sequence or order, and the like of the corresponding elements are not limited by the terms. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meanings as those generally understood by those with ordinary knowledge in the field of art to which the present disclosure belongs. Such terms as those defined in a generally used dictionary are to be interpreted as having meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted as having ideal or excessively formal meanings unless clearly defined as having such in the present application. 
     A vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may allow a vehicle door to open and close selectively in any one mode of a sliding mode and a swing mode. In other words, the vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may be a transform-type door opening and closing apparatus. The sliding mode may allow the vehicle door to open and close by sliding in a longitudinal direction of a vehicle, and the swing mode may allow the vehicle door to open and close by swinging inwards and outwards. 
     Referring to  FIG. 1 , a vehicle body  1  may have a plurality of door apertures  2  and  3 , and the plurality of door apertures  2  and  3  may be divided into a front aperture  2  and a rear aperture  3 . A plurality of vehicle doors  4  and  5  may include a front door  4  covering and uncovering the front aperture  2 , and a rear door  5  covering and uncovering the rear aperture  3 . As the front door  4  is opened, the front door  4  may uncover the front aperture  2 , and as the front door  4  is closed, the front door  4  may cover the front aperture  2 . As the rear door  5  is opened, the rear door  5  may uncover the rear aperture  3 , and as the rear door  5  is closed, the rear door  5  may cover the rear aperture  3 . 
     The vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may be applied to the front door  4 , the rear door  5 , and the like.  FIGS. 1 to 16  illustrate a vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure, which is applied to the rear door  5 . Hereinafter, the rear door  5  will be referred to as the vehicle door  5 , and the rear aperture  3  will be referred to as the door aperture  3 . 
     The vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may include one or more rails  11  and  12  mounted on the vehicle body  1 , and the rails  11  and  12  may extend in the longitudinal direction of the vehicle. Referring to  FIG. 1 , an upper rail  11  may be mounted on an upper edge of the vehicle body  1 , and a lower rail  12  may be mounted on a lower edge of the vehicle body  1 . The upper rail  11  and the lower rail  12  may extend in the longitudinal direction of the vehicle. The upper rail  11  may be disposed on an upper edge of the door aperture  3 , and the lower rail  12  may be disposed on a lower edge of the door aperture  3 . 
     The vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may include roller units  21  and  22  guided along the rails  11  and  12 . The roller units  21  and  22  may allow the vehicle door  5  to open and close in one mode selected from the sliding mode and the swing mode. In particular, the roller units  21  and  22  may be releasably held in predetermined positions of the rails  11  and  12  by hold locks  31  and  32 . Specifically, when the roller units  21  and  22  are held in the predetermined positions of the rails  11  and  12  by the hold locks  31  and  32 , the vehicle door  5  may be opened and closed in the swing mode in which the vehicle door swings in the predetermined positions of the rails  11  and  12 . When the roller units  21  and  22  are released by the hold locks  31  and  32 , the vehicle door  5  may be opened and closed in the sliding mode in which the vehicle door slides along the rails  11  and  12 . 
     Referring to  FIGS. 1 and 3 , an upper roller unit  21  may be mounted on an upper end of the vehicle door  5 , and the upper roller unit  21  may slide along the upper rail  11 . A lower roller unit  22  may be mounted on a lower end of the vehicle door  5 , and the lower roller unit  22  may slide along the lower rail  12 . 
     Referring to  FIG. 2 , the vehicle door  5  may include an outside handle  6 , and a selector  40  for selecting the sliding mode and the swing mode may be adjacent to the outside handle  6 . The selector  40  may have a first switch  41  selecting the sliding mode, and a second switch  42  selecting the swing mode. 
     When a user presses the first switch  41  and the sliding mode is selected, the vehicle door  5  may slide along the upper rail  11 , the lower rail  12 , and a center rail  13  as illustrated in  FIG. 3  as the user pushes the outside handle  6  toward the front of the vehicle or pulls the outside handle  6  toward the rear of the vehicle. In the sliding mode, the vehicle door  5  may move between a first open position OP 1  in which the vehicle door  5  is fully opened and a first closed position CP 1  in which the vehicle door  5  is fully closed, as illustrated in  FIGS. 1 and 3 . 
     When the user presses the second switch  42  and the swing mode is selected, the vehicle door  5  may swing as illustrated in  FIG. 4  as the user pushes or pulls the outside handle  6  toward a passenger compartment of the vehicle or toward the exterior side of the vehicle. In the swing mode, the vehicle door  5  may move between a second open position OP 2  in which the vehicle door  5  is fully opened and a second closed position CP 2  in which the vehicle door  5  is fully closed, as illustrated in  FIGS. 7 and 9 . In particular, when the vehicle door  5  is held in the first closed position CP 1 , it may be operated in the swing mode. 
     The upper roller unit  21  may have an upper hold lock  31 , and the vehicle body  1  may have a first upper striker  31   a  and a second upper striker  31   b  protruding downwardly from a roof of the vehicle body  1 . The first upper striker  31   a  may be aligned with or adjacent to a virtual axis of the first closed position CP 1 , and the second upper striker  31   b  may be aligned with or adjacent to a virtual axis of the first open position OP 1 . 
     According to an exemplary embodiment, as illustrated in  FIGS. 1 and 3 , the upper hold lock  31  may releasably hold the first upper striker  31   a  in the first closed position CP 1 , and releasably hold the second upper striker  31   b  in the first open position OP 1 . That is, one upper hold lock  31  may selectively hold the first upper striker  31   a  and the second upper striker  31   b . As the upper hold lock  31  holds the first upper striker  31   a , the upper roller unit  21  may be firmly held in the first closed position CP 1 , so that the vehicle door  5  may be kept in the first closed position CP 1 . As the upper hold lock  31  holds the second upper striker  31   b , the upper roller unit  21  may be firmly held in the first open position OP 1 , so that the vehicle door  5  may be kept in the first open position OP 1 . 
     According to another exemplary embodiment, the upper hold lock  31  may releasably hold the first upper striker  31   a  in the first closed position CP 1  so that the vehicle door  5  may be kept in the first closed position CP 1 . That is, the upper hold lock  31  may be an upper closed hold lock which keeps the closed state of the vehicle door  5  in the first closed position CP 1 . An upper open hold lock (not shown) may be mounted on the upper roller unit  21 , and may releasably hold the second upper striker  31   b  in the first open position OP 1 . That is, the upper closed hold lock, which releasably holds the first upper striker  31   a  in the first closed position CP 1 , and the upper open hold lock, which releasably holds the second upper striker  31   b  in the first open position OP 1 , may be individually mounted on the upper roller unit  21 . 
     Referring to  FIGS. 4 and 9 , the upper roller unit  21  may have an upper rotation axis CX 1 , and the vehicle door  5  may rotate around the upper rotation axis CX 1 . When the upper roller unit  21  is firmly held in the first closed position CP 1  by the upper hold lock  31  and the first upper striker  31   a , the vehicle door  5  may rotate around the upper rotation axis CX 1 . 
     The lower roller unit  22  may have a lower hold lock  32 , and the vehicle body  1  may have a first lower striker  32   a  and a second lower striker  32   b  protruding upwardly from the bottom of the vehicle body  1 . The first lower striker  32   a  may be aligned with or adjacent to the virtual axis of the first closed position CP 1 , and the second lower striker  32   b  may be aligned with or adjacent to the virtual axis of the first open position OP 1 . 
     According to an exemplary embodiment, as illustrated in  FIGS. 1 and 3 , the lower hold lock  32  may releasably hold the first lower striker  32   a  in the first closed position CP 1 , and releasably hold the second lower striker  32   b  in the first open position OP 1 . That is, one lower hold lock  32  may selectively hold the first lower striker  32   a  and the second lower striker  32   b . As the lower hold lock  32  holds the first lower striker  32   a , the lower roller unit  22  may be firmly held in the first closed position CP 1 , so that the vehicle door  5  may be kept in the first closed position CP 1 . As the lower hold lock  32  holds the second lower striker  32   b , the lower roller unit  22  may be firmly held in the first open position OP 1 , so that the vehicle door  5  may be kept in the first open position OP 1 . 
     According to another exemplary embodiment, the lower hold lock  32  may releasably hold the first lower striker  32   a  in the first closed position CP 1  so that the vehicle door  5  may be kept in the first closed position CP 1 . That is, the lower hold lock  32  may be a lower closed hold lock which keeps the closed state of the vehicle door  5  in the first closed position CP 1 . A lower open hold lock (not shown) may be mounted on the lower roller unit  22 , and may releasably hold the second lower striker  32   b  in the first open position OP 1 . That is, the lower closed hold lock, which releasably holds the first lower striker  32   a  in the first closed position CP 1 , and the lower open hold lock, which releasably holds the second lower striker  32   b  in the first open position OP 1 , may be individually mounted on the lower roller unit  22 . 
     According to an exemplary embodiment, the vehicle door  5  may be releasably held in the first closed position CP 1  by the upper hold lock  31  and the lower hold lock  32 , so that the vehicle door  5  may be kept in the first closed position CP 1  by the upper hold lock  31  and the lower hold lock  32 . That is, the upper hold lock  31  and the lower hold lock  32  may function as the closed hold lock which holds the vehicle door  5  in the first closed position CP 1 . 
     Referring to  FIGS. 4 and 9 , the lower roller unit  22  may have a lower rotation axis CX 2 , and the vehicle door  5  may rotate around the lower rotation axis CX 2 . When the lower roller unit  22  is firmly held in the first closed position CP 1  by the lower hold lock  32  and the first lower striker  32   a , the vehicle door  5  may rotate around the lower rotation axis CX 2 . 
     As illustrated in  FIG. 4 , the upper rotation axis CX 1  and the lower rotation axis CX 2  may be vertically aligned, and the vehicle door  5  may rotate around the vertically aligned upper and lower rotation axes CX 1  and CX 2 . 
     Referring to  FIG. 2 , the selector  40  may be electrically connected to an actuator  43 , and the actuator  43  may be configured to operate the upper hold lock  31  and the lower hold lock  32 . 
     As the user selects the selector  40 , the actuator  43  may selectively perform a hold operation in which the upper hold lock  31  holds the first upper striker  31   a  and the lower hold lock  32  holds the first lower striker  32   a , and a release operation in which the upper hold lock  31  releases the first upper striker  31   a  and the lower hold lock  32  releases the first lower striker  32   a.    
     When the user presses the first switch  41  of the selector  40  in a state in which the vehicle door  5  is closed, the upper hold lock  31  may release the first upper striker  31   a  and the lower hold lock  32  may release the first lower striker  32   a  simultaneously by the release operation of the actuator  43 . Thus, the user may slide the vehicle door  5  in the longitudinal direction of the vehicle body  1  so that the vehicle door  5  may be opened and closed in the sliding mode. 
     When the user presses the second switch  42  of the selector  40  in a state in which the vehicle door  5  is closed, the upper hold lock  31  may hold the first upper striker  31   a  and the lower hold lock  32  may hold the first lower striker  32   a  simultaneously by the hold operation of the actuator  43 , and the upper roller unit  21  and the lower roller unit  22  may be firmly held in the first closed position CP 1 . Thus, the user may swing the vehicle door  5  toward an interior space and an exterior space of the vehicle so that the vehicle door  5  may be opened and closed in the swing mode. 
     According to an exemplary embodiment, as illustrated in  FIG. 2 , one actuator  43  may operate the upper hold lock  31  and the lower hold lock  32  simultaneously. 
     According to another exemplary embodiment, an actuator operating the upper hold lock  31  and another actuator operating the lower hold lock  32  may be individually connected to the selector  40 . 
       FIGS. 10A to 10D  illustrate the upper hold lock  31  and the lower hold lock  32  according to an exemplary embodiment of the present disclosure. Referring to  FIGS. 10A  to  10 D, each of the upper hold lock  31  and the lower hold lock  32  may include a catch  71 , a pawl  72  releasably engaging with the catch  71 , and a lever  73  operatively connected to the pawl  72 . The lever  73  may be connected to the actuator  43  through a cable  75 . As the cable  75  is reversed (pulled) by the actuator  43 , the catch  71  may release the strikers  31   a  and  32   a . A portion of the catch  71 , the pawl  72 , and the lever  73  may be covered by a cover plate  76 , and the cover plate  76  may be attached to a mounting plate  74 . The strikers  31   a  and  32   a  may be fixed to the vehicle body  1  by a mounting plate  78 . 
     Referring to  FIGS. 10A to 10D , the upper hold lock  31  may releasably hold the first upper striker  31   a , and the lower hold lock  32  may releasably hold the first lower striker  32   a.    
     The catch  71  may be pivotally mounted on the mounting plate  74  through a first pivot shaft  71   a . The catch  71  may have a slot  71   b  receiving the strikers  31   a  and  32   a , and the catch  71  may engage and release the strikers  31   a  and  32   a . The catch  71  may move between an engaging position (see  FIG. 10B ) and a release position (see  FIG. 1C ). The engaging position refers to a position in which the catch  71  engages with the strikers  31   a  and  32   a  as illustrated in  FIG. 10B , and the release position refers to a position in which the catch  71  releases the strikers  31   a  and  32   a  as illustrated in  FIG. 10C . When the catch  71  is in the engaging position as illustrated in  FIG. 10B , the catch  71  may engage with the strikers  31   a  and  32   a  so that the catch  71  may hold the strikers  31   a  and  32   a . When the catch  71  is in the release position as illustrated in  FIG. 10C , the catch  71  may release the strikers  31   a  and  32   a . Thus, the strikers  31   a  and  32   a  may be released from the slot  71   b  of the catch  71  or be received in the slot  71   b  of the catch  71 . The catch  71  may be biased toward the release position by a first biasing element  71   c  such as a torsion spring. The first biasing element  71   c  may be disposed around the first pivot shaft  71   a . The catch  71  may have a locking shoulder  71   d.    
     The pawl  72  may be pivotally mounted on the mounting plate  74  through a second pivot shaft  72   a , and the pawl  72  may move between a pawl locking position (see  FIG. 10B ) and a pawl release position (see  FIGS. 10C and 10D ). The pawl locking position refers to a position in which the pawl  72  engages with the catch  71  and the catch  71  is kept in the engaging position, and the pawl release position refers to a position in which the pawl  72  releases the catch  71  and the catch  71  is allowed to move from the engaging position to the release position. As illustrated in  FIG. 10B , when the pawl  72  is in the pawl locking position, the movement (rotation) of the catch  71  may be restricted by the pawl  72  so that the catch  71  may be kept in the engaging position. As illustrated in  FIGS. 10C and 10D , when the pawl  72  is in the pawl release position, the movement (rotation) of the catch  71  may not be restricted by the pawl  72  so that the catch  71  may move from the engaging position to the release position. The pawl  72  may be biased toward the pawl locking position (see  FIG. 10B ) by a second biasing element  72   c  such as a torsion spring. The second biasing element  72   c  may be disposed around the second pivot shaft  72   a.    
     The pawl  72  may have a locking projection  72   d  locked to the locking shoulder  71   d  of the catch  71 . As illustrated in  FIG. 10B , as the pawl  72  is moved to the pawl locking position by the second biasing element  72   c , the locking projection  72   d  of the pawl  72  may be locked to the locking shoulder  71   d  of the catch  71  and the movement (rotation) of the catch  71  may be restricted, so that the catch  71  may be kept in the engaging position. As illustrated in  FIG. 10C , as the pawl  72  is moved to the pawl release position by the lever  73 , the locking projection  72   d  of the pawl  72  may be released from the locking shoulder  71   d  of the catch  71  and the movement (rotation) of the catch  71  may be allowed, so that the catch  71  may be moved to the release position by the first biasing element  71   c.    
     The lever  73  may be pivotally mounted on the mounting plate  74  through a third pivot shaft  73   a . The lever  73  may be connected to the actuator  43  through the cable  75 . An end of the cable  75  may be fixed to the lever  73 , and the cable  75  may be advanced or reversed by the actuator  43 . As the actuator  43  moves the cable  75 , the lever  73  may pivot around the third pivot shaft  73   a . The lever  73  may move the pawl  72  to the pawl release position (see  FIG. 10C ) by reversing the cable  75 . 
     The lever  73  may be operatively connected to the pawl  72  through a pin  72   b  and an opening  73   b . The pin  72   b  may be provided on the pawl  72 , and the opening  73   b  may be provided in the lever  73 . The pin  72   b  may be movably received in the opening  73   b . As the lever  73  pivots around the third pivot shaft  73   a , the pin  72   b  may move in the opening  73   b , allowing the pawl  72  to move. 
     As illustrated in  FIG. 10B , when the cable  75  is advanced by the actuator  43 , the locking projection  72   d  of the pawl  72  may be locked to the locking shoulder  71   d  of the catch  71  and the movement (rotation) of the catch  71  may be restricted so that the catch  71  may be kept in the engaging position. The strikers  31   a  and  32   a  may be held in the slot  71   b  of the catch  71 . That is, the upper hold lock  31  and the lower hold lock  32  may hold the corresponding strikers  31   a  and  32   a.    
     As illustrated in  FIG. 10C , when the cable  75  is reversed by the actuator  43 , the lever  73  may move the pawl  72  to the pawl release position. The locking projection  72   d  of the pawl  72  may be released from the locking shoulder  71   d  of the catch  71  and the movement (rotation) of the catch  71  may be allowed, so that the catch  71  may be moved to the release position by the first biasing element  71   c , and the strikers  31   a  and  32   a  may be released from the slot  71   b  of the catch  71 . Thus, the upper hold lock  31  and the lower hold lock  32  may release the corresponding strikers  31   a  and  32   a , and the upper roller unit  21  and the lower roller unit  22  may slide along the upper rail  11  and the lower rail  12 . 
     As illustrated in  FIG. 10D , even though the cable  75  is advanced by the actuator  43  in a state in which the locking projection  72   d  of the pawl  72  is released from the locking shoulder  71   d  of the catch  71 , the catch  71  may be kept in the release position by the first biasing element  71   c  so that the movement (rotation) of the catch  71  may be allowed. In this state, the strikers  31   a  and  32   a  may be allowed to be received in the slot  71   b  of the catch  71 . That is, in a state in which the movement (rotation) of the catch  71  is allowed as the locking projection  72   d  of the pawl  72  is released from the locking shoulder  71   d  of the catch  71 , when the upper roller unit  21  and the lower roller unit  22  slide between the first closed position CP 1  and the first open position OP 1 , the strikers  31   a  and  32   a  may be allowed to be received in the slot  71   b  of the catch  71 . When a force applied by the upper hold lock  31  and the lower hold lock  32  in a state in which the strikers  31   a  and  32   a  are received in the slot  71   b  of the catch  71  is greater than a spring force of the first biasing element  71   c , the catch  71  may be moved to the engaging position. As illustrated in  FIG. 10B , as the locking projection  72   d  of the pawl  72  is locked to the locking shoulder  71   d  of the catch  71 , the catch  71  may hold the strikers  31   a  and  32   a.    
     Referring to  FIG. 5 , each of the upper rail  11  and the lower rail  12  may be mounted on the vehicle body  1  through a mounting bracket  15 , and the mounting bracket  15  may have a shape corresponding to that of the upper rail  11  and the lower rail  12 . Each of the upper rail  11  and the lower rail  12  may have a first extension portion  51  extending straightly in the longitudinal direction of the vehicle, and a second extension portion  52  extending from the first extension portion  51  toward the interior space of the vehicle. The second extension portion  52  may be bent with respect to the first extension portion  51  at a predetermined angle. 
     Referring to  FIG. 6 , each of the upper roller unit  21  and the lower roller unit  22  may include a roller bracket  64  having rollers  65  and  66  rolling along the rails  11  and  12 , and a body  60  connecting the roller bracket  64  and the vehicle door  5 . 
     The body  60  may extend diagonally so as not to contact the first extension portion  51  and the second extension portion  52 . The body  60  may have a first end portion  61  facing the interior side of the vehicle, and a second end portion  62  facing the exterior side of the vehicle. The first end portion  61  of the body  60  may be attached to the roller bracket  64 , and the second end portion  62  of the body  60  may be attached to the vehicle door  5 . 
     The roller bracket  64  may rotatably support the rollers  65  and  66 , and the rollers  65  and  66  may roll along the upper rail  11  and the lower rail  12 . As illustrated in  FIG. 6 , a middle roller  65  and two side rollers  66  disposed on both sides of the middle roller  65  may be rotatably mounted on the roller bracket  64 . A rotation axis of the middle roller  65  may be orthogonal to a rotation axis of the side roller  66 . 
     According to an exemplary embodiment, as illustrated in  FIG. 6 , the first end portion  61  of the body  60  may be pivotally connected to the roller bracket  64  through a pivot pin  68 , and the second end portion  62  of the body  60  may be fixed to the vehicle door  5 . Thus, the vehicle door  5  may swing around the pivot pin  68  adjacent to the roller bracket  64 . The body  60  may have a pivot lug  63  protruding from the first end portion  61  toward the roller bracket  64 , and the roller bracket  64  may be connected to the pivot lug  63  through the pivot pin  68 . The roller bracket  64  may be shaped so as not to interfere with the body  60  when the vehicle door  5  swings. The upper rotation axis CX 1  and the lower rotation axis CX 2  may be defined by the pivot pin  68 . For example, the upper rotation axis CX 1  and the lower rotation axis CX 2  may be a virtual axis extending vertically along a center point of the pivot pin  68 , and the upper rotation axis CX 1  and the lower rotation axis CX 2  may be vertically aligned, so that the vehicle door  5  may swing around the vertical rotation axis that virtually connects the upper rotation axis CX 1  and the lower rotation axis CX 2 . The upper hold lock  31  may be fixed to the roller bracket  64  of the upper roller unit  21 , and the lower hold lock  32  may be fixed to the roller bracket  64  of the lower roller unit  22 . 
     When, by the hold operation of the actuator  43 , the upper hold lock  31  firmly holds the roller bracket  64  of the upper roller unit  21  in the first closed position CP 1  and the lower hold lock  32  firmly holds the roller bracket  64  of the lower roller unit  22  in the first closed position CP 1 , the vehicle door  5  may swing around the upper rotation axis CX 1  of the upper roller unit  21  and the lower rotation axis CX 2  of the lower roller unit  22  as illustrated in  FIG. 7 . The vehicle door  5  may move between the second closed position CP 2  in which the vehicle door  5  is closed and the second open position OP 2  in which the vehicle door  5  is opened. When the vehicle door  5  swings, another adjacent door  4  or other components may be spaced apart from the vehicle door  5  by a predetermined gap S 1  so as not to interfere with the door  4  or the other components. For example, the vehicle door  5  may be a rear door, and another adjacent door  4  may be a front door. 
     According to the exemplary embodiment illustrated in  FIGS. 6 and 7 , as the pivot pin  68  is located between the roller bracket  64  and the first end portion  61  of the body  60 , the rotation axes CX 1  and CX 2  of the vehicle door  5  may be relatively far from the vehicle door  5 . Since a swing trajectory T 1  and a rotation radius R 1  of the vehicle door  5  are relatively increased, the gap S 1  between the vehicle door  5  and the adjacent door  4  may be relatively increased. If the gap S 1  between the vehicle door  5  and the adjacent door  4  is reduced, the vehicle door  5  may interfere with the adjacent door  4  when the vehicle door  5  moves toward the second open position OP 2 , and an open space created by the swing of the vehicle door  5  may be relatively narrowed since the swing trajectory T 1  of the vehicle door  5  is relatively reduced. 
     According to another exemplary embodiment, as illustrated in  FIGS. 8 and 9 , the first end portion  61  of the body  60  may be fixed to the roller bracket  64 , and the second end portion  62  of the body  60  may be pivotally connected to the vehicle door  5  through a pivot pin  68   a . Thus, the vehicle door  5  may swing around the pivot pin  68   a  adjacent to the second end portion  62  of the body  60 . 
     Referring to  FIGS. 8 and 9 , the roller bracket  64  may be fixed to the first end portion  61  of the body  60  by welding, using fasteners, and/or the like. The second end portion  62  of the body  60  may be pivotally connected to the vehicle door  5  through the pivot pin  68   a . A pivot lug  69  may be mounted to the vehicle door  5  by welding, using fasteners, and/or the like. The pivot lug  69  may protrude toward the body  60 . The pivot lug  69  may be pivotally connected to the second end portion  62  of the body  60  through the pivot pin  68   a . The second end portion  62  of the body  60  may be shaped so as not to interfere with the vehicle door  5  when the vehicle door  5  swings. The upper rotation axis CX 1  and the lower rotation axis CX 2  may be defined by the pivot pin  68   a . For example, the upper rotation axis CX 1  and the lower rotation axis CX 2  may be a virtual axis extending vertically along a center point of the pivot pin  68   a , and the upper rotation axis CX 1  and the lower rotation axis CX 2  may be vertically aligned, so that the vehicle door  5  may swing around the vertical rotation axis that virtually connects the upper rotation axis CX 1  and the lower rotation axis CX 2 . The upper hold lock  31  may be fixed to the body  60  of the upper roller unit  21 , and the lower hold lock  32  may be fixed to the body  60  of the lower roller unit  22 . 
     Referring to  FIG. 9 , when the upper hold lock  31  firmly holds the roller bracket  64  of the upper roller unit  21  in the first closed position CP 1 , and the lower hold lock  32  firmly holds the roller bracket  64  of the lower roller unit  22  in the first closed position CP 1 , the vehicle door  5  may swing around the upper rotation axis CX 1  of the upper roller unit  21  and the lower rotation axis CX 2  of the lower roller unit  22 . Thus, the vehicle door  5  may move between the second closed position CP 2  in which the vehicle door  5  is closed and the second open position OP 2  in which the vehicle door  5  is opened. 
     According to the exemplary embodiment illustrated in  FIGS. 8 and 9 , as the pivot pin  68   a  is located between the second end portion  62  of the body  60  and the vehicle door  5 , the rotation axes CX 1  and CX 2  of the vehicle door  5  may be relatively close to the vehicle door  5 . Since a rotation radius R 2  of the vehicle door  5  is relatively shortened, a gap S 2  between the vehicle door  5  and another adjacent door  4  may be relatively reduced, resulting in improved exterior styling. Even though the rotation axes CX 1  and CX 2  of the vehicle door  5  are close to the vehicle door  5 , a swing trajectory T 2  of the vehicle door  5  is not reduced, and thus an open space created by the swing of the vehicle door  5  may not be narrowed. 
     Referring to  FIG. 11 , a main latch  80  may be mounted on a rear end of the vehicle door  5 , and a main striker  81  may be fixed to the vehicle body  1 . The main latch  80  may releasably engage with the main striker  81 . When the vehicle door  5  is in the first closed position CP 1  or the second closed position CP 2 , the main latch  80  may engage with the main striker  81  by an engaging operation of the outside handle  6  so that the vehicle door  5  may be locked in the first closed position CP 1  or the second closed position CP 2 . When the vehicle door  5  is in the first closed position CP 1  or the second closed position CP 2 , the main latch  80  may release the main striker  81  by a release operation of the outside handle  6  so that the vehicle door  5  may be allowed to move in the sliding mode or the swing mode. When the vehicle door  5  is held in the first closed position CP 1  and the main latch  80  releases the main striker  81 , a center roller unit  23  may be released from the center rail  13 , and thus the vehicle door  5  may be opened and closed in the swing mode. 
     The vehicle door opening and closing apparatus, according to exemplary embodiments of the present disclosure, may further include the center rail  13  mounted at a central portion of the vehicle body  1 , and the center roller unit  23  guided along the center rail  13 . 
     Referring to  FIGS. 1 and 3 , the center rail  13  may extend from a rear edge of the door aperture  3  in the longitudinal direction of the vehicle. The center roller unit  23  may be pivotally mounted at a central portion of the vehicle door  5 . In particular, the center roller unit  23  may be mounted in a position adjacent to the rear end of the vehicle door  5 . The center roller unit  23  may be guided along the center rail  13 . 
     Referring to  FIG. 12 , the center rail  13  may include a sliding guide  91  extending straightly in the longitudinal direction of the vehicle, and a swing guide  92  extending from the sliding guide  91  toward the interior side of the vehicle. The swing guide  92  may be bent at a predetermined angle with respect to the sliding guide  91  through a bending portion  93 , and the bending portion  93  may be curved at a predetermined radius. 
     Referring to  FIGS. 13 to 15 , the center roller unit  23  may include a roller bracket  101  and rollers  105  and  106  rotatably mounted on the roller bracket  101 . The roller bracket  101  may be pivotally mounted at the central portion of the vehicle door  5 . The rollers  105  and  106  may roll along the center rail  13 . As illustrated in  FIG. 15 , a middle roller  105  and two side rollers  106  disposed on both sides of the middle roller  105  may be rotatably mounted on the roller bracket  101 . A rotation axis of the middle roller  105  may be orthogonal to a rotation axis of the side roller  106 . 
     When the vehicle door  5  slides in the longitudinal direction of the vehicle as the sliding mode is selected, the sliding guide  91  may guide the center roller unit  23 . 
     Referring to  FIGS. 12 and 14 , the sliding guide  91  may include a stopper wall  95  preventing the rollers  105  and  106  of the center roller unit  23  from being separated from the sliding guide  91 . The stopper wall  95  may extend along a length of the sliding guide  91  and a length of the bending portion  93 . The stopper wall  95  may protrude vertically downward from the top of the sliding guide  91 . As the stopper wall  95  closes an upper area of the sliding guide  91  and an upper area of the bending portion  93 , the center roller unit  23  may be prevented from moving away from the sliding guide  91  toward the exterior side of the vehicle as illustrated in  FIG. 14 . 
     When the vehicle door  5  is opened and closed in the swing mode as the swing mode is selected, the swing guide  92  may guide the rollers  105  and  106  of the center roller unit  23  to be released from the center rail  13 . 
     An exterior side of the swing guide  92  may be entirely opened toward the exterior space of the vehicle. A guide projection  94  may protrude upwardly from the bottom of the swing guide  92 , and the guide projection  94  may extend along a length of the swing guide  92 . When the vehicle door  5  swings from the second closed position CP 2  to the second open position OP 2  along the swing trajectory T 1  or T 2 , the middle roller  105  of the center roller unit  23  may be guided along the guide projection  94  as illustrated in  FIG. 13 . 
     A front end  95   a  of the stopper wall  95  of the sliding guide  91  and a rear end  94   a  of the guide projection  94  may be located so as not to interfere with the swing trajectories T 1  and T 2  of the vehicle door  5 . In addition, as illustrated in  FIG. 16 , an axis X 1  of the sliding guide  91  and an axis X 2  of the swing guide  92  may intersect at a predetermined angle a. In particular, the angle a of intersection between the axis X 1  of the sliding guide  91  and the axis X 2  of the swing guide  92  may be an obtuse angle, so that the center roller unit  23  may easily be released from the swing guide  92  of the center rail  13  or may easily be held in the swing guide  92  of the center rail  13 . The center rail  13  may include a space  98  allowing the rollers  105  and  1   o   6  of the center roller unit  23  to be released from the center rail  13  or be held in the center rail  13  when the vehicle door  5  swings in the swing mode. The space  98  may be defined between the front end  95   a  of the stopper wall  95  and the rear end  94   a  of the guide projection  94  as the front end  95   a  of the stopper wall  95  and the rear end  94   a  of the guide projection  94  are spaced apart from each other. Thus, there is no interference when the rollers  105  and  1   o   6  of the center roller unit  23  are released from the center rail  13  or are held in the center rail  13  in the swing mode. 
     Referring to  FIGS. 17 and 18 , a vehicle door check mechanism  110  may be disposed between the vehicle door  5  and the rails  11  and  12  of the vehicle body to allow the vehicle door  5  to be held and stopped at regular intervals. When the vehicle door  5  is opened in the swing mode, the vehicle door check mechanism  110  may allow the vehicle door  5  to be held and stopped at predetermined intervals. 
     The vehicle door check mechanism  110  may include a strap body  111  mounted on portions of the vehicle door  5  adjacent to the rotation axes CX 1  and CX 2 . Referring to  FIGS. 17 to 28 , the pivot lug  69  may have a mounting portion  69   a . The mounting portion  69   a  may be mounted to the vehicle door  5  by welding, using fasteners, and/or the like. Specifically, the strap body  111  may be mounted to the vehicle door  5  or the mounting portion  69   a  of the pivot lug  69 , and the strap body  111  may move with the vehicle door  5  when the vehicle door  5  swings around the rotation axes CX 1  and CX 2 . As illustrated in  FIGS. 17 and 18 , the strap body  111  may have a fixed end  191  fixed to the pivot lug  69  or the vehicle door  5 , and a free end  192  spaced apart from the vehicle door  5 . 
     The strap body  111  may be curved to have a predetermined curvature radius R, and the center of the curvature radius R of the strap body  111  may be located on the rotation axes CX 1  and CX 2  of the vehicle door  5 . When the vehicle door  5  swings around the rotation axes CX 1  and CX 2 , the strap body  111  may move along a circular pathway CPW defined by the swing trajectory of the vehicle door  5 . 
     The vehicle door check mechanism  110 , according to exemplary embodiments of the present disclosure, may include a guide member  112  guiding the movement of the strap body  111 . The guide member  112  may be mounted on the body  60  of the roller units  21  and  22 . The guide member  112  may have a guide passage  114  through which the strap body in passes, and the guide passage  114  may be shaped to correspond to a cross section of the strap body in. 
     When the vehicle door  5  is opened and closed in the swing mode, a hold unit allowing the strap body  111  to be held and stopped at regular intervals may be mounted on the roller units  21  and  22 . Specific examples of the hold unit will be illustrated in  FIGS. 19 to 28 . 
     As such, the vehicle door check mechanism  110  may allow the vehicle door  5  to be held and stopped at regular intervals when the vehicle door  5  moves along the swing trajectory. 
     Referring to  FIGS. 19 to 21 , the vehicle door check mechanism  110  may include a first hold member  121  and a second hold member  122  disposed on both sides of the strap body in, and the first hold member  121  and the second hold member  122  may be curved to correspond to the curvature of the strap body in. The first hold member  121  and the second hold member  122  may be mounted on the body  60  of the roller units  21  and  22 . The first hold member  121  may have a plurality of recesses  131  and  133 , and the plurality of recesses  131  and  133  may be spaced apart from each other in a longitudinal direction of the first hold member  121 . The second hold member  122  may have a plurality of recesses  132  and  134  corresponding to the plurality of recesses  131  and  133  of the first hold member  121 , respectively, and the plurality of recesses  132  and  134  may be spaced apart from each other in a longitudinal direction of the second hold member  122 . For example, a first recess  131  of the first hold member  121  may be spaced apart from a second recess  132  of the second hold member  122  in a radial direction of the circular pathway CPW, and a third recess  133  of the first hold member  121  may be spaced apart from a fourth recess  134  of the second hold member  122  in the radial direction of the circular pathway CPW. 
     The strap body  111  may have a first projection  113  protruding from the free end  192  toward the first hold member  121 , and a second projection  116  protruding from the free end  192  toward the second hold member  122 . The first projection  113  and the second projection  116  may be semicircular. The first projection  113  may be selectively received in any one of the recesses  131  and  133  of the first hold member  121 , and the second projection  116  may be selectively received in any one of the recesses  132  and  134  of the second hold member  122 . 
     The first hold member  121  may have a first cushion material  123  contacting the first projection  113 , and the first cushion material  123  may be attached to the first hold member  121  by coating and/or the like. The second hold member  122  may have a second cushion material  124  contacting the second projection  116 , and the second cushion material  124  may be attached to the second hold member  122  by coating and/or the like. For example, the first cushion material  123  and the second cushion material  124  may be polyoxymethylene (POM). Durability and operability of the vehicle door check mechanism  110  may be improved by the first and second cushion materials  123  and  124 . 
     As illustrated in  FIG. 20 , in a condition in which the vehicle door  5  is closed, the first projection  113  of the strap body  111  may be received in the first recess  131  of the first hold member  121 , and the second projection  116  of the strap body  111  may be received in the second recess  132  of the second hold member  122  so that the strap body  111  may be held and stopped in a first position. As illustrated in  FIG. 21 , in a condition in which the vehicle door  5  is partially opened, the first projection  113  of the strap body  111  may be received in the third recess  133  of the first hold member  121 , and the second projection  116  of the strap body  111  may be received in the fourth recess  134  of the second hold member  122  so that the strap body  111  may be held and stopped in a second position. In a condition in which the vehicle door  5  is fully opened, the first projection  113  and the second projection  116  of the strap body  111  may be stopped by the guide member  112 . 
       FIGS. 22 to 25  illustrate a vehicle door check mechanism  210  according to another exemplary embodiment of the present disclosure. Here, the vehicle door check mechanism  210  may include a strap body  211  having a fixed end  291  and a free end  292 , a roller  215  rotatably mounted on the free end  292  of the strap body  211 , and a hold member  250  mounted on the body  60  of the roller units  21  and  22 . 
     The strap body  211  may be mounted on portions of the vehicle door  5  adjacent to the rotation axes CX 1  and CX 2  in the same manner as in the preceding embodiment. Specifically, the strap body  211  may be mounted on the pivot lug  69  or the vehicle door  5 , and the strap body  211  may move with the vehicle door  5  when the vehicle door  5  swings around the rotation axes CX 1  and CX 2 . The fixed end  291  may be fixed to the mounting portion  69   a  of the pivot lug  69  or the vehicle door  5 , and the free end  292  may be spaced apart from the vehicle door  5 . 
     The hold member  250  may be curved to correspond to the curvature of the strap body  211 , and the hold member  250  may be located below the strap body  211 . The hold member  250  may be attached to the body  60  of the roller units  21  and  22 . 
     The hold member  250  may have a plurality of recesses  251 ,  252 , and  253 , and the plurality of recesses  251 ,  252 , and  253  may be spaced apart from each other in a longitudinal direction of the hold member  250 . 
     When the vehicle door  5  is opened and closed in the swing mode, the roller  215  may roll along the hold member  250 , and the roller  215  may be selectively received in any one of the recesses  251 ,  252 , and  253  of the hold member  250 , and thus the strap body  211  may be held and stopped at regular intervals. 
     Referring to  FIG. 26 , a vehicle door check mechanism  310  according to another exemplary embodiment of the present disclosure may include a strap body  311  mounted on the vehicle door  5 , and a strap housing  320  allowing the strap body  311  to be held and stopped at regular intervals. The strap body  311  may be mounted on portions of the vehicle door  5  adjacent to the rotation axes CX 1  and CX 2  in the same manner as in the preceding embodiment. Specifically, the strap body  311  may be mounted on the pivot lug  69  or the vehicle door  5 , and the strap body  311  may move with the vehicle door  5  when the vehicle door  5  swings around the rotation axes CX 1  and CX 2 . The strap body  311  may have a fixed end  391  fixed to the mounting portion  69   a  of the pivot lug  69  or the vehicle door  5 , and a free end  392  spaced apart from the vehicle door  5 . 
     The strap body  311  may have an inner peripheral surface facing the rotation axes CX 1  and CX 2  of the vehicle door  5 , that is, the pivot lug  69 , and an outer peripheral surface opposing the inner peripheral surface. The strap body  311  may have a plurality of inner peripheral recesses  313 ,  315 , and  317  facing the rotation axes CX 1  and CX 2  of the vehicle door  5 , and a plurality of outer peripheral recesses  312 ,  314 , and  316  opposing the plurality of inner peripheral recesses  313 ,  315 , and  317 . The plurality of inner peripheral recesses  313 ,  315 , and  317  may be spaced apart from each other along the inner peripheral surface of the strap body  311 , and the plurality of outer peripheral recesses  312 ,  314 , and  316  may be spaced apart from each other along the outer peripheral surface of the strap body  311 . 
     The strap housing  320  may be mounted on the body  60  of the roller units  21  and  22 , and the strap housing  320  may have a passage through which the strap body  311  passes. Thus, the strap housing  320  may guide the movement of the strap body  311 . 
     A first ball  321  and a second ball  322  may be mounted in the strap housing  320 , allowing the strap body  311  to be held and stopped at regular intervals. The first ball  321  may be selectively received in any one of the outer peripheral recesses  312 ,  314 , and  316  of the strap body  311 , and the second ball  322  may be selectively received in any one of the inner peripheral recesses  313 ,  315 , and  317  of the strap body  311 . 
     The first ball  321  may be supported by a first ball support  325 , and the first ball support  325  may be elastically supported by a first elastic member  327 . The second ball  322  may be supported by a second ball support  324 , and the second ball support  324  may be elastically supported by a second elastic member  326 . 
     When the vehicle door  5  is opened and closed in the swing mode, the first ball  321  and the second ball  322  of the strap housing  320  may be symmetrically received in the recesses  312 ,  313 ,  314 ,  315 ,  316 , and  317  of the strap body  311 , and thus the strap body  311  may be held and stopped at regular intervals. 
     According to the exemplary embodiment illustrated in  FIG. 26 , the recesses  312 ,  313 ,  314 ,  315 ,  316 , and  317  of the strap body  311  may be arranged in a plane orthogonal to a height direction of the vehicle, and the first ball  321  and the second ball  322  of the strap housing  320  may be oppositely received in corresponding recesses selected from the recesses  312 ,  313 ,  314 ,  315 ,  316 , and  317  of the strap body  311 . Thus, the vehicle door check mechanism  310  may operate normally without being affected by deflection or deformation of the vehicle door  5 . 
     Referring to  FIGS. 27 and 28 , a vehicle door check mechanism  410  according to another exemplary embodiment of the present disclosure may include a strap body  411  mounted on the vehicle door  5 , a cam member  420  allowing the strap body  411  to be held and stopped at regular intervals, and a guide member  412  guiding the movement of the strap body  411 . 
     The strap body  411  may be mounted on portions of the vehicle door  5  adjacent to the rotation axes CX 1  and CX 2  in the same manner as in the preceding embodiment. Specifically, the strap body  411  may be mounted on the pivot lug  69  or the vehicle door  5 , and the strap body  411  may move with the vehicle door  5  when the vehicle door  5  swings around the rotation axes CX 1  and CX 2 . The strap body  411  may have a fixed end  491  fixed to the mounting portion  69   a  of the pivot lug  69  or the vehicle door  5 , and a free end  492  spaced apart from the vehicle door  5 . 
     The strap body  411  may have an inner peripheral surface facing the rotation axes CX 1  and CX 2  of the vehicle door  5 , that is, the pivot lug  69 , and an outer peripheral surface opposing the inner peripheral surface. A plurality of recesses  413 ,  414 ,  415 , and  416  may be spaced apart from each other along the inner peripheral surface of the strap body  411 . 
     The cam member  420  may have a projection  421  selectively received in any one of the recesses  413 ,  414 ,  415 , and  416  of the strap body  411 . The cam member  420  may be rotatably mounted on the body  60  of the roller units  21  and  22  through a shaft  426 . In particular, the cam member  420  may allow the projection  421  to be biased toward the recesses  413 ,  414 ,  415 , and  416  by a biasing element  425 . The biasing element  425  may be a torsion spring disposed around the shaft  426 . 
     The vehicle door check mechanism  410  may further include a guide roller  430  guiding the movement of the strap body  411 . The guide roller  430  may be rotatably mounted on the body  60  of the roller units  21  and  22 . In particular, the guide roller  430  may be disposed to face the cam member  420 , and the guide roller  430  may make rolling contact with the outer peripheral surface of the strap body  411 . 
     The guide member  412  may have a guide passage through which the strap body  411  passes and the guide passage may be shaped to correspond to a cross section of the strap body  411 . The guide member  412  may be mounted on the body  60  of the roller units  21  and  22 . 
     When the vehicle door  5  is opened and closed in the swing mode, the projection  421  of the cam member  420  may be received in any one of the recesses  413 ,  414 ,  415 , and  416  of the strap body  411 , and thus the strap body  411  may be held and stopped at regular intervals. 
       FIGS. 17 to 28  illustrate the vehicle door check mechanism  110 ,  210 ,  310 , or  410  applied to the roller units  21  and  22  of  FIG. 9 , but the vehicle door check mechanism  110 ,  210 ,  310 , or  410  may also be applied to the roller units  21  and  22  of  FIG. 6 . In addition, the vehicle door check mechanism  110 ,  210 ,  310 , or  410  according to the exemplary embodiments of the present disclosure may be applied to various swing-type vehicle doors, in addition to the vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure. For example, the strap body  111 ,  211 ,  311 , or  411  of the vehicle door check mechanism  110 ,  210 ,  310 , or  410  may be mounted on the vehicle door, and the first and second hold members  121  and  122  of the hold unit, the hold member  250 , the strap housing  320 , or the cam member  420  may be mounted on a hinge component (for example, a hinge bracket) connecting the vehicle door and the vehicle body. 
       FIGS. 1 to 28  illustrate the vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure applied to the rear door  5 . However, the vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure may be applied to various vehicle doors, such as front doors, in addition to rear doors. 
       FIGS. 29 and 30  illustrate the vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure applied to the front door  4 .  FIG. 29  illustrates a state in which the front door  4  is opened in the sliding mode, and  FIG. 30  illustrates a state in which the front door  4  is opened in the swing mode. 
       FIGS. 31 and 32  illustrate the vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure applied to both the front door  4  and the rear door  5 .  FIG. 31  illustrates a state in which the front door  4  and the rear door  5  are opened in the sliding mode, and  FIG. 32  illustrates a state in which the front door  4  and the rear door  5  are opened in the swing mode. 
     As set forth above, the vehicle door check mechanism according to exemplary embodiments of the present disclosure may have a curved structure corresponding to the swing trajectory of the vehicle door, which makes the mounting thereof easy even when a space between the vehicle door and the vehicle body is narrow as in a pillarless vehicle, and reliably ensures a vehicle door check operation. 
     The vehicle door opening and closing apparatus according to exemplary embodiments of the present disclosure may perform the opening and closing operations of the vehicle door by selectively switching the sliding mode and the swing mode, thereby meeting the needs of customers such as convenience and diversity. In addition, it may select the opening and closing operations of the vehicle door by taking the customer&#39;s situation and environment into consideration, thereby improving convenience and quality. 
     In terms of vehicle specifications, the vehicle door opening and closing structure may be standardized, regardless of vehicle models. Thus, the manufacturing cost and investment cost may be significantly reduced. 
     Hereinabove, although the present disclosure has been described with reference to exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure claimed in the following claims.