Patent Publication Number: US-2021180370-A1

Title: Vehicular door lock device and vehicular door lock system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2019-226257, filed on Dec. 16, 2019, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This disclosure generally relates to a vehicular door lock device and a vehicular door lock system. 
     BACKGROUND DISCUSSION 
     JP2005-88812A (Reference 1) describes a vehicle including a vehicle body in which a door opening is formed on a side portion, and a front slide door and a rear slide door that open and close the door opening. The front slide door opens a front half of the door opening by sliding forward, and the rear slide door opens a rear half of the door opening by sliding rearward. 
     As described above, in a vehicle including double slide doors, a striker cannot be installed on a center pillar in a point that the center pillar is not present. In other words, in the vehicle as described above, a door lock device that restrains the slide door in a full closed position is needed even without a striker to be installed on the center pillar. Note that such a circumference is a circumference that is not limited to a vehicle including double slide doors and is also mostly common to a vehicle without a striker located in such a way as to face an end portion in a close direction of a door. 
     A need thus exists for a vehicular door lock device and a vehicular door lock system which are not susceptible to the drawback mentioned above. 
     SUMMARY 
     A vehicular door lock device that solves the problem described above is a vehicular door lock device that is provided on one of a door and a vehicle body, and restrains the door to the vehicle body by engaging with a striker provided on another of the door and the vehicle body. The vehicular door lock device includes a base being fixed to one of the door and the vehicle body, a first hook and a second hook each including a base end portion being rotatably supported by the base, and a driving body that is rotatably supported by the base and drives the first hook and the second hook. The first hook and the second hook rotate between an engaged position of sandwiching the striker by tip portions being close to each other and a retracted position in which the tip portions are separated from each other. The driving body is displaced between a first position in which the first hook and the second hook are disposed in the engaged position and a second position in which the first hook and the second hook are disposed in the retracted position. 
     A vehicular door lock system that solves the problem described above includes the vehicular door lock device described above, and the striker. The striker is provided on a lower end of a door opening to be opened and closed by the door in a state where a portion sandwiched between the first hook and the second hook extends in a vehicle front-rear direction. The vehicular door lock device is provided on the door in a state where a rotational shaft line of the first hook and a rotational shaft line of the second hook extend in the vehicle front-rear direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein: 
         FIG. 1  is a side view illustrating a schematic configuration of a vehicle according to a first embodiment; 
         FIG. 2  is a perspective view of a lower lock device and a lower lock driving device according to the first embodiment; 
         FIG. 3  is a front view of the lower lock device according to the first embodiment; 
         FIG. 4  is a side view of the lower lock driving device according to the first embodiment; 
         FIG. 5  is a perspective view of a floor of a vehicle body according to the first embodiment; 
         FIG. 6  is an exploded perspective view of the floor of the vehicle body according to the first embodiment; 
         FIG. 7  is a perspective view of the lower lock device and a peripheral configuration when a first hook and a second hook are located in a retracted position in the first embodiment; 
         FIG. 8  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in the retracted position in the first embodiment; 
         FIG. 9  is a perspective view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in an engaged position in the first embodiment; 
         FIG. 10  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in the engaged position in the first embodiment; 
         FIG. 11  is a perspective view of the lower lock device and the peripheral configuration when the first hook and the second hook return to the retracted position in the first embodiment; 
         FIG. 12  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook return to the retracted position in the first embodiment; 
         FIG. 13  is a perspective view of a lower lock device and a lower lock driving device according to a second embodiment; 
         FIG. 14  is a front view of the lower lock device according to the second embodiment; 
         FIG. 15  is a perspective view of the lower lock device and a peripheral configuration when a first hook and a second hook are located in a retracted position in the second embodiment; 
         FIG. 16  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in the retracted position in the second embodiment; 
         FIG. 17  is a perspective view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in an engaged position in the second embodiment; 
         FIG. 18  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook are located in the engaged position in the second embodiment; 
         FIG. 19  is a perspective view of the lower lock device and the peripheral configuration when the first hook and the second hook return to the retracted position in the second embodiment; 
         FIG. 20  is a front view of the lower lock device and the peripheral configuration when the first hook and the second hook return to the retracted position in the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
     A first embodiment of a vehicle including a vehicular door lock system will be described below. In the following description, it is assumed that an axis extending in a vehicle width direction is an X axis, an axis extending in a vehicle front-rear direction is a Y axis, and an axis extending in a vehicle up-down direction is a Z axis. 
     As illustrated in  FIG. 1 , the vehicle  10  includes a vehicle body  20  including a door opening  21 , and a slide door  30  that opens and closes the door opening  21 . 
     The vehicle body  20  includes upper rails  22 F and  22 R disposed above the door opening  21 , center rails  23 F and  23 R disposed at the front and the rear of the door opening  21 , respectively, and door driving units  24 F and  24 R that drive the slide door  30 . Further, the vehicle body  20  includes a front striker  25 F provided at the front of the door opening  21 , a rear striker  25 R provided at the rear of the door opening  21 , and lower strikers  26 F and  26 R ( 26 ) provided on a lower end portion of the door opening  21  at the center in the front-rear direction of the door opening  21 . 
     The upper rail  22 F and the center rail  23 F are disposed at the front with respect to the center in the front-rear direction of the door opening  21 , and the upper rail  22 R and the center rail  23 R are disposed at the rear with respect to the center in the front-rear direction of the door opening  21 . The upper rails  22 F and  22 R and the center rails  23 F and  23 R extend substantially in the front-rear direction. 
     The door driving units  24 F and  24 R are configured to include, for example, a motor and a transmission mechanism for transmitting power of the motor to the slide door  30 . The transmission mechanism of the door driving units  24 F and  24 R can also be configured to include a pulley and a belt, and can also be configured to include a drum and a cable. Note that the door driving units  24 F and  24 R can be built in the slide door  30 . 
     The slide door  30  includes a first slide door  30 F that opens and closes a range from the center to a front end in the front-rear direction of the door opening  21 , and a second slide door  30 R that opens and closes a range from the center to a rear end in the front-rear direction of the door opening  21 . It is assumed that a position when the slide door  30  fully opens the door opening  21  is a “full open position”, and a position when the slide door  30  fully closes the door opening  21  is a “full closed position”. It can be said that the slide door  30  according to the present embodiment is a so-called power slide door in a point that the door driving units  24 F and  24 R cause open/close operations between the full closed position and the full open position. 
     The first slide door  30 F performs the open operation by moving to the front, and performs the close operation by moving to the rear. On the other hand, the second slide door  30 R performs the open operation by moving to the rear, and performs the close operation by moving to the front. In other words, the first slide door  30 F and the second slide door  30 R perform the open operation by moving in a direction away from each other, and perform the close operation by moving in a direction close to each other. 
     The first slide door  30 F includes an upper guide unit  31 F and a center guide unit  32 F that move along the upper rail  22 F and the center rail  23 F, respectively, and a door handle  33 F disposed on a surface facing a compartment. Further, the first slide door  30 F includes a front lock device  34 F that restrains a front end portion of the first slide door  30 F to the vehicle body  20 , a center lock device  35 F that couples a rear end portion of the first slide door  30 F and a front end portion of the second slide door  30 R, and a lower lock device  40 F ( 40 ) that restrains a lower end portion of the first slide door  30 F to the vehicle body  20 . 
     Further, the first slide door  30 F includes a front lock driving device  36 F that drives the front lock device  34 F, a lower lock driving device  50 F ( 50 ) that drives the lower lock device  40 F, the door handle  33 F, a remote control  37 F that relays power transmitted among the front lock driving device  36 F, the center lock device  35 F, and the lower lock device  40 F. Furthermore, the first slide door  30 F includes a first cable  381 F that connects the front lock driving device  36 F and the remote control  37 F, a second cable  382 F that connects the remote control  37 F and the center lock device  35 F, a third cable  383 F that connects the remote control  37 F and the lower lock device  40 F, and a fourth cable  384 F that connects the remote control  37 F and the front lock driving device  36 F. 
     The front lock device  34 F includes a latch  341  that engages with the front striker  25 F. The front lock device  34 F switches between an engagement state where the latch  341  engages with the front striker  25 F and a release state where the latch  341  does not engage with the front striker  25 F. 
     The center lock device  35 F includes a latch  351  that engages with a center striker  35 R of the second slide door  30 R, which will be described later. The center lock device  35 F switches between an engagement state where the latch  351  engages with the center striker  35 R and a release state where the latch  351  does not engage with the center striker  35 R. 
     The lower lock device  40 F switches between an engagement state where a first hook  421  and a second hook  422 , which will be described later, engage with the lower striker  26 F and a release state where the first hook  421  and the second hook  422  do not engage with the lower striker  26 F. 
     Then, by being in the engagement state, the front lock device  34 F, the center lock device  35 F, and the lower lock device  40 F restrain the first slide door  30 F in the full closed position. 
     The front lock driving device  36 F shifts the front lock device  34 F from the release state to the engagement state, and shifts the front lock device  34 F from the engagement state to the release state. After the first slide door  30 F performs the close operation to the vicinity of the full closed position, the front lock driving device  36 F shifts the front lock device  34 F from the release state to the engagement state, and thus moves the first slide door  30 F to the full closed position. 
     On the other hand, when the first slide door  30 F performs the open operation from the full closed position, the front lock driving device  36 F shifts the front lock device  34 F from the engagement state to the release state, and thus releases a restraint of the first slide door  30 F by the front lock device  34 F. Further, when the front lock driving device  36 F shifts the front lock device  34 F from the engagement state to the release state, the front lock driving device  36 F pulls the first cable  381 F. 
     The lower lock driving device  50 F shifts the lower lock device  40 F from the release state to the engagement state. After the front lock driving device  36 F shifts the front lock device  34 F to the engagement state, that is, after the first slide door  30 F is disposed in the full closed position, the lower lock driving device  50 F shifts the lower lock device  40 F to the engagement state. In this way, the lower lock driving device  50 F restrains the lower end portion of the first slide door  30 F to the vehicle body  20 . 
     Note that a timing at which the lower lock driving device  50 F shifts the lower lock device  40 F to the engagement state can be the same timing as a timing at which the front lock driving device  36 F shifts the front lock device  34 F to the engagement state. 
     When the front lock driving device  36 F shifts the front lock device  34 F to the release state, that is, when the front lock driving device  36 F pulls the first cable  381 F, the remote control  37 F pulls the second cable  382 F and the third cable  383 F. Then, the remote control  37 F shifts the center lock device  35 F and the lower lock device  40 F from the engagement state to the release state. 
     Further, when a user performs an open operation on the door handle  33 F, the remote control  37 F pulls the second cable  382 F, the third cable  383 F, and the fourth cable  384 F. Then, the remote control  37 F shifts the front lock device  34 F, the center lock device  35 F, and the lower lock device  40 F from the engagement state to the release state. 
     Next, the second slide door  30 R will be described. 
     The second slide door  30 R includes an upper guide unit  31 R and a center guide unit  32 R that move along the upper rail  22 R and the center rail  23 R, respectively, and a door handle  33 R disposed on a surface facing the compartment. Further, the second slide door  30 R includes a rear lock device  34 R that restrains a rear end portion of the second slide door  30 R to the vehicle body  20 , the center striker  35 R coupled to the rear end portion of the first slide door  30 F, and a lower lock device  40 R ( 40 ) that restrains a lower end portion of the second slide door  30 R to the vehicle body  20 . 
     Further, the second slide door  30 R includes a rear lock driving device  36 R that drives the rear lock device  34 R, a lower lock driving device  50 R ( 50 ) that drives the lower lock device  40 R, the door handle  33 R, and a remote control  37 R that relays power transmitted between the rear lock driving device  36 R and the lower lock device  40 R. Furthermore, the second slide door  30 R includes a first cable  381 R that connects the rear lock driving device  36 R and the remote control  37 R, a third cable  383 R that connects the remote control  37 R and the lower lock device  40 R, and a fourth cable  384 R that connects the remote control  37 R and the rear lock driving device  36 R. 
     The second slide door  30 R is configured substantially similarly to the first slide door  30 F except for a point that the second slide door  30 R includes the rear lock device  34 R instead of the front lock device  34 F, a point that the second slide door  30 R includes the center striker  35 R instead of the center lock device  35 F, and a point that the second slide door  30 R does not include a cable corresponding to the second cable  382 F. Thus, description of the configuration in the second slide door  30 R except for the center striker  35 R will be omitted. 
     The center striker  35 R is installed on the front end portion of the second slide door  30 R and in a position facing the center lock device  35 F of the first slide door  30 F in the front-rear direction. The center striker  35 R is a subject engaged with the latch  351  of the center lock device  35 F. 
     Next, the lower lock device  40  and the lower lock driving device  50  will be described in detail. In the present embodiment, both of the lower lock devices  40 F and  40 R correspond to one example of a “vehicular door lock device”. Further, the lower lock devices  40 F and  40 R have a symmetrical shape with respect to a surface orthogonal to the front-rear direction, and the lower lock driving devices  50 F and  50 R have a symmetrical shape with respect to the surface orthogonal to the front-rear direction. Thus, in the following description, the lower lock device  40 F and the lower lock driving device  50 F will be described by using the reference signs of the lower lock device  40  and the lower lock driving device  50 . 
     As illustrated in  FIGS. 2 and 3 , the lower lock device  40  includes a base  41  assembled to the slide door  30 , the first hook  421  and the second hook  422  that engage with the lower striker  26 , and a driving link  43  that drives the first hook  421  and the second hook  422 . Further, the lower lock device  40  includes a first link  441  that couples the first hook  421  and the driving link  43 , a second link  442  that couples the second hook  422  and the driving link  43 , a pole  45  that engages with the driving link  43 , and a release lever  46  that drives the pole  45 . Further, the lower lock device  40  includes a hook biasing spring  471  that biases the second hook  422 , a pole biasing spring  472  that biases the pole  45 , and a release lever biasing spring  473  that biases the release lever  46 . 
     Further, the lower lock device  40  includes a first support shaft  481  as one example of a “support shaft” that rotatably supports both of the first hook  421  and the second hook  422 , a second support shaft  482  that rotatably supports the driving link  43 , a third support shaft  483  that rotatably supports the pole  45 , and a fourth support shaft  484  that rotatably supports the release lever  46 . Furthermore, the lower lock device  40  includes a first coupling shaft  491  that relatively rotatably couples the first hook  421  and the first link  441 , a second coupling shaft  492  that relatively rotatably couples the driving link  43  and the first link  441 , a third coupling shaft  493  that relatively rotatably couples the second hook  422  and the second link  442 , and a fourth coupling shaft  494  that relatively rotatably couples the driving link  43  and the second link  442 . 
     As illustrated in  FIGS. 2 and 3 , the base  41  includes a first base  411  and a second base  412  having a flat plate shape. The first base  411  extends in a direction intersecting the second base  412  from the second base  412 . Thus, the base  41  has a substantially L shape in a plan view from above. The first base  411  is fixed to the slide door  30  via a fastening member such as a bolt. The second base  412  is coupled to the lower lock driving device  50  via a fastening member such as a bolt. 
     As illustrated in  FIG. 3 , the first hook  421  and the second hook  422  are a plate-shaped member having a substantially triangular shape in a front view. The first hook  421  and the second hook  422  are disposed on a lower end portion of the first base  411  by the first support shaft  481  having the front-rear direction as a shaft direction. In other words, a rotational shaft line of the first hook  421  and the second hook  422  extends in the front-rear direction. 
     In the first hook  421 , when a portion supported by the first support shaft  481  and the first coupling shaft  491  is assumed to be a base end portion, the first hook  421  includes an engagement claw  423  and a recessed portion  424  on a tip portion. The engagement claw  423  extends in a rotational direction of the first hook  421 , and the recessed portion  424  is recessed in an opposite direction to the direction in which the engagement claw  423  extends. 
     Similarly, in the second hook  422 , when a portion supported by the first support shaft  481  and the third coupling shaft  493  is assumed to be a base end portion, the second hook  422  includes an engagement claw  423  and a recessed portion  424  on a tip portion. The engagement claw  423  extends in a rotational direction of the second hook  422 , and the recessed portion  424  is recessed in an opposite direction to the direction in which the engagement claw  423  extends. A size of the recessed portion  424  of the first hook  421  and the second hook  422  is a size corresponding to the lower striker  26 . 
     The first hook  421  and the second hook  422  rotate about a shaft line of the first support shaft  481  between an engaged position of sandwiching the lower striker  26  by bringing the tip portions closer to each other and a retracted position in which the tip portions are separated from each other. In the present embodiment, when the first hook  421  and the second hook  422  rotate between the engaged position and the retracted position, the first hook  421  and the second hook  422  have a positional relationship having substantial line symmetry with respect to a straight line passing through the center of the first support shaft  481  and extending in the up-down direction in  FIG. 3 . Further, when the first hook  421  and the second hook  422  are located in the engaged position, the lower striker  26  fits into the recessed portion  424  of the first hook  421  and the second hook  422 . 
     As illustrated in  FIGS. 2 and 3 , the driving link  43  has a flat plate shape. The driving link  43  is disposed on a central portion of the first base  411  by the second support shaft  482  having the front-rear direction as a shaft direction. In other words, the driving link  43  is disposed at an interval from the first hook  421  and the second hook  422  in the up-down direction. As illustrated in  FIG. 3 , the driving link  43  includes an engagement protrusion  431  extending in a direction orthogonal to a rotational direction of the driving link  43 , a slide surface  432  extending in the rotational direction of the driving link  43 , and a regulation surface  433  extending in a direction that intersects the slide surface  432 . The driving link  43  corresponds to one example of a “driving body”. 
     As illustrated in  FIG. 3 , the first link  441  constitutes a four-joint link mechanism together with the driving link  43 , the first base  411 , and the first hook  421 . In the four-joint link mechanism including the first link  441 , a distance between shaft lines of the first support shaft  481  and the second support shaft  482  is longer than a distance between shaft lines of the first coupling shaft  491  and the second coupling shaft  492 . Further, a distance between shaft lines of the first support shaft  481  and the first coupling shaft  491  and a distance between shaft lines of the second support shaft  482  and the second coupling shaft  492  are shorter than the distance between the shaft lines of the first coupling shaft  491  and the second coupling shaft  492 . The first link  441  corresponds to a so-called intermediate link, and transmits power of the driving link  43  to the first hook  421 . 
     On the other hand, the second link  442  constitutes a four-joint link mechanism together with the driving link  43 , the first base  411 , and the second hook  422 . In the four-joint link mechanism including the second link  442 , the distance between the shaft lines of the first support shaft  481  and the second support shaft  482  is longer than a distance between shaft lines of the third coupling shaft  493  and the fourth coupling shaft  494 . Further, a distance between shaft lines of the first support shaft  481  and the third coupling shaft  493  and a distance between shaft lines of the second support shaft  482  and the fourth coupling shaft  494  are shorter than the distance between the shaft lines of the third coupling shaft  493  and the fourth coupling shaft  494 . The second link  442  corresponds to a so-called intermediate link, and transmits power of the driving link  43  to the second hook  422 . 
     The four-joint link mechanism including the first link  441  and the four-joint link mechanism including the second link  442  share the driving link  43 . Thus, when the driving link  43  rotates, the first hook  421  and the second hook  422  rotate together. Further, when one of the first hook  421  and the second hook  422  rotates, the other of the first hook  421  and the second hook  422  rotates with the driving link  43 . In other words, the first hook  421 , the second hook  422 , the driving link  43 , the first link  441 , and the second link  442  operate with each other. Therefore, when a position of the driving link  43  is determined, positions of the first hook  421  and the second hook  422  are also uniquely defined. 
     In the following description, it is assumed that a position of the driving link  43  when the first hook  421  and the second hook  422  are disposed in the engaged position is a “first position”, and a position of the driving link  43  when the first hook  421  and the second hook  422  are disposed in the retracted position is a “second position”. Further, the driving link  43  is displaced between the first position and the second position by rotating about the shaft line of the second support shaft  482 . 
     As illustrated in  FIGS. 2 and 3 , the pole  45  is disposed on an upper portion of the first base  411  by the third support shaft  483  having the front-rear direction as a shaft direction. In other words, the pole  45  is disposed above the driving link  43 . The pole  45  includes a first engagement piece  451  and a second engagement piece  452  extending in a direction that intersects the shaft direction of the third support shaft  483 . The first engagement piece  451  extends toward the driving link  43 , and the second engagement piece  452  extends toward the second base  412 . 
     As illustrated in  FIG. 2 , the release lever  46  is disposed on an upper portion of the second base  412  by the fourth support shaft  484  having the width direction as a shaft direction. The release lever  46  includes a first lever  461  and a second lever  462  extending in a direction that intersects the shaft direction of the fourth support shaft  484 . The first lever  461  extends toward the first base  411 , and the second lever  462  extends along the first base  411 . An end portion of the third cable  383 F extending from the remote control  37 F is fixed to a tip of the second lever  462 . When the third cable  383 F is pulled, the release lever  46  rotates in a direction in which a tip of the first lever  461  is lowered. 
     As illustrated in  FIGS. 2 and 3 , the hook biasing spring  471  is a so-called extension coil spring. The hook biasing spring  471  has one end engaged with the third support shaft  483 , and has another end engaged with the third coupling shaft  493 . The hook biasing spring  471  biases the second hook  422  in a direction in which the second hook  422  rotates from the engaged position toward the retracted position. 
     As described above, when the second hook  422  rotates, the first hook  421  rotates, and thus it can also be said that the hook biasing spring  471  biases both of the first hook  421  and the second hook  422 . Further, when the second hook  422  rotates, the driving link  43  rotates, and thus it can also be said that the hook biasing spring  471  biases the driving link  43  in a direction from the first position toward the second position. In this respect, the hook biasing spring  471  can replace the configuration in which the first hook  421  is biased, and can also replace the configuration in which the driving link  43  is biased. 
     As illustrated in  FIGS. 2 and 3 , the pole biasing spring  472  is a so-called torsion coil spring. The pole biasing spring  472  has one end engaged with the first base  411 , and has another end engaged with the second engagement piece  452  of the pole  45 , while the third support shaft  483  is inserted. The pole biasing spring  472  biases the pole  45  in a direction in which the first engagement piece  451  pushes the driving link  43 . 
     As illustrated in  FIG. 2 , the release lever biasing spring  473  is a so-called torsion coil spring. The release lever biasing spring  473  has one end engaged with a support plate  51  of the lower lock driving device  50 , which will be described later, and has another end engaged with the second lever  462  of the release lever  46 , while the fourth support shaft  484  is inserted. The release lever biasing spring  473  biases the release lever  46  in a direction in which the tip of the first lever  461  of the release lever  46  moves away from the second engagement piece  452  of the pole  45 . 
     Next, the lower lock driving device  50  will be described. 
     As illustrated in  FIGS. 2 and 4 , the lower lock driving device  50  includes the support plate  51  having a flat plate shape, a drive gear  52  rotatably supported by the support plate  51 , an active lever  53  rotatably supported by the support plate  51 , a coupling link  54  rotatably supported by the support plate  51 , a close lever  55  that couples the active lever  53  and the coupling link  54 , and a driving unit  56  that drives the drive gear  52 . 
     The support plate  51  is coupled to the base  41  of the lower lock device  40  with a fastening member such as a bolt. The support plate  51  can also be integrally formed with the base  41  of the lower lock device  40 . The active lever  53  includes a gear portion  531  that meshes with the drive gear  52 , and a lever portion  532  coupled to the coupling link  54 . The lever portion  532  extends toward the first base  411  of the lower lock device  40 . 
     Then, the support plate  51 , the active lever  53 , the coupling link  54 , and the close lever  55  constitute a four-joint link mechanism. Thus, when the active lever  53  rotates in one direction and another direction, the close lever  55  moves up and down. The driving unit  56  is configured to include a motor and a transmission mechanism for transmitting power of the motor to the drive gear  52 . The driving unit  56  rotates the active lever  53  by rotating the drive gear  52 . In this way, the lower lock driving device  50  operates the close lever  55  at any timing. 
     Next, a configuration according to the lower striker  26  will be described. 
     As illustrated in  FIGS. 5 and 6 , the vehicle body  20  includes a floor  27  in which the lower striker  26  described above is disposed, and a covering plate  28  that covers the lower striker  26 . 
     The floor  27  includes a housing recessed portion  271  that houses the lower striker  26 . The housing recessed portion  271  is provided in an outer end of the floor  27  in the width direction. In other words, the housing recessed portion  271  is provided in a lower end of the door opening  21 . In the lower striker  26 , a rod-like portion engaging with the first hook  421  and the second hook  422  of the lower lock device  40  extends in the front-rear direction. In other words, in the lower striker  26 , the portion sandwiched between the first hook  421  and the second hook  422  extends in the front-rear direction. 
     The covering plate  28  includes a slit  281  having the width direction as a long-side direction and having the front-rear direction as a short-side direction. In other words, the slit  281  extends in a direction orthogonal to the direction in which the rod-like portion of the lower striker  26  extends, i.e., the width direction. The covering plate  28  is fixed to the floor  27  of the vehicle body  20  while covering the housing recessed portion  271 . At this time, the covering plate  28  is preferably flush with the floor  27  of the vehicle body  20 . Further, the covering plate  28  exposes the rod-like shape of the lower striker  26  to above from the slit  281 . 
     In the present embodiment, one example of a “vehicular door lock system” including the lower lock device  40 , the lower lock driving device  50 , the lower striker  26 , and the covering plate  28  described above is constituted. 
     Action of the present embodiment will be described. 
     Specifically, with reference to  FIGS. 1 and 7 to 12 , action of the lower lock device  40  and the lower lock driving device  50  during the close operation and the open operation of the slide door  30  will be described. 
     In the vehicle  10 , when there is a request for the close operation of the slide door  30  from a user, the door driving units  24 F and  24 R are driven, and the close operation of the slide door  30  starts. When the slide door  30  performs the close operation to the vicinity of the full closed position, the front lock driving device  36 F and the rear lock driving device  36 R are driven instead of the door driving units  24 F and  24 R. As a result, the front lock device  34 F and the rear lock device  34 R shift to the engagement state, and the slide door  30  is disposed in the full closed position in which the slide door  30  fully closes the door opening  21 . 
     When the slide door  30  is disposed in the full closed position, the rear end portion of the first slide door  30 F and the front end portion of the second slide door  30 R are located the closest to each other. Thus, the latch  351  of the center lock device  35 F of the first slide door  30 F engages with the center striker  35 R of the second slide door  30 R. In other words, when the slide door  30  is disposed in the full open position, the center lock device  35 F also shifts to the engagement state. Power for shifting the center lock device  35 F to the engagement state is a force of the center striker  35 R pushing the latch  351  due to the close operation of the slide door  30 . 
     At a stage at which the front lock device  34 F, the rear lock device  34 R, and the center lock device  35 F shift to the engagement state, moment due to a dead weight acts on the slide door  30  and an elastic force of a weather strip compressed between the vehicle body  20  and the slide door  30  acts on the slide door  30 , and thus an attitude of the lower end portion of the slide door  30  is not determined. Thus, the attitude of the lower end portion of the slide door  30  needs to be stable with the lower lock device  40  in the engagement state. 
     Thus, after the slide door  30  is disposed in the full closed position, the lower lock driving device  50  is driven. Specifically, the driving unit  56  is driven, and thus the active lever  53  rotates in a direction indicated by a solid line arrow in  FIG. 7 . Then, the close lever  55  rises in a direction indicated by a solid line arrow in  FIG. 8 , and the close lever  55  pushes the engagement protrusion  431  of the driving link  43  upward. As a result, the driving link  43  rotates in a first rotational direction R 1  from the second position, and power is transmitted to the first hook  421  and the second hook  422  via the first link  441  and the second link  442 . Further, when the driving link  43  rotates in the first rotational direction R 1 , the first engagement piece  451  of the pole  45  slides on the slide surface  432  of the driving link  43 . 
     As illustrated in  FIGS. 9 and 10 , when the close lever  55  rises the highest, the driving link  43  is disposed in the first position. When the driving link  43  is disposed in the first position, the pole  45  rotates based on a biasing force of the pole biasing spring  472 , and the first engagement piece  451  of the pole  45  engages with the regulation surface  433  of the driving link  43 . In other words, it is impossible for the driving link  43  to rotate toward the second position. 
     Further, when the driving link  43  is disposed in the first position, the first hook  421  and the second hook  422  rotate about the shaft line of the first support shaft  481  in directions different from each other, and thus are located in the engaged position of sandwiching the lower striker  26 . In this way, a movement of the lower portion of the slide door  30  in the width direction is restricted, and the attitude of the slide door  30  in the full closed position is stable. Further, when the first hook  421  and the second hook  422  rotate to the engaged position, the hook biasing spring  471  is extended. 
     As illustrated in  FIG. 10 , when the first hook  421  and the second hook  422  rotate to the engaged position, the first hook  421  brings the lower striker  26  relatively into the width direction, and thus the first hook  421  brings the lower portion of the slide door  30  inward in the width direction. Thus, as illustrated in  FIGS. 8 and 10 , a position of the lower portion of the slide door  30  when the first hook  421  and the second hook  422  are disposed in the engaged position is located inward in the width direction further than a position of the lower portion of the slide door  30  when the first hook  421  and the second hook  422  are disposed in the retracted position. In other words, the first hook  421  and the second hook  422  rotate from the retracted position to the engaged position, and thus the lower portion of the slide door  30  moves inward in the width direction. Further, when the first hook  421  and the second hook  422  are disposed in the engaged position, only the first hook  421  is in a contact state with the lower striker  26  in order to fasten the slide door  30  that is to move outward in the width direction. 
     After the driving link  43  is disposed in the first position, the driving unit  56  of the lower lock driving device  50  is driven, and thus the active lever  53  rotates in a direction indicated by a solid line arrow in  FIG. 9 . In other words, the close lever  55  is lowered in a direction indicated by a solid line arrow in  FIG. 10 , and the close lever  55  is separated from the engagement protrusion  431  of the driving link  43 . However, the pole  45  makes it impossible for the driving link  43  to rotate toward the second position, and thus the driving link  43  remains in the first position even after the active lever  53  is separated from the engagement protrusion  431  of the driving link  43 . In other words, the first hook  421  and the second hook  422  also remain in the engaged position. 
     Subsequently, when there is a request for the open operation of the slide door  30  from a user, the front lock driving device  36 F and the rear lock driving device  36 R are driven. As a result, the front lock device  34 F and the rear lock device  34 R shift to the release state, and the center lock device  35 F and the lower lock device  40  shift to the release state. 
     As illustrated in  FIG. 11 , in the lower lock device  40 , the remote control  37 F pulls the third cable  383 F in a direction indicated by a solid line arrow, and thus the release lever  46  rotates in a direction indicated by a solid line arrow. In other words, as illustrated in  FIG. 12 , the first lever  461  of the release lever  46  is lowered, and the first lever  461  of the release lever  46  pushes down the second engagement piece  452  of the pole  45 . Then, the first engagement piece  451  of the pole  45  is separated from the driving link  43 , and the first engagement piece  451  of the pole  45  does not engage with the regulation surface  433  of the driving link  43 . 
     The first hook  421  and the second hook  422  are biased by the hook biasing spring  422  in the direction in which the first hook  421  and the second hook  422  rotate from the engaged position toward the retracted position. Thus, after the pole  45  does not engage with the driving link  43 , the first hook  421  and the second hook  422  rotate toward the retracted position, and the driving link  43  rotates in a second rotational direction R 2 . When the first hook  421  and the second hook  422  return to the retracted position, the driving link  43  returns to the second position. In this way, the lower lock device  40  shifts to the state illustrated in  FIGS. 7 and 8 , i.e., the release state. 
     When the front lock device  34 F, the rear lock device  34 R, the center lock device  35 F, and the lower lock device  40  shift to the release state, the slide door  30  is not restrained to the vehicle body  20 . Thus, the door driving units  24 F and  24 R are driven, and the open operation of the slide door  30  starts. 
     Effects of the first embodiment will be described. 
     (1) The first hook  421  and the second hook  422  sandwich the lower striker  26 , and thus the lower lock device  40  restrains the slide door  30  to the vehicle body  20 . In other words, as long as the first hook  421  and the second hook  422  can sandwich the lower striker  26 , the lower lock device  40  can restrain the slide door  30  to the vehicle body  20 . In this respect, flexibility in arrangement of the first hook  421  and the second hook  422  with respect to the lower striker  26  is more likely to be increased. Therefore, the lower lock device  40  can restrain the slide door  30  in the full closed position regardless of an installation place of the lower striker  26 . 
     (2) Power of the driving link  43  is transmitted to the first hook  421  and the second hook  422  by the link mechanism. Thus, the lower lock device  40  can achieve a power transmission mechanism for rotating the first hook  421  and the second hook  422  in different directions with a simple configuration. 
     (3) The lower lock device  40  includes the pole  45  that restricts rotation of the driving link  43  to the second position by engaging with the driving link  43  disposed in the first position. Thus, the lower lock device  40  can fasten the first hook  421  and the second hook  422  in the engaged position even without the lower lock driving device  50  continuing to be driven. Further, the lower lock device  40  can simplify the configuration of the device in a point that the pole  45  may be one. 
     (4) The lower lock device  40  includes the first support shaft  481  that rotatably supports both of the first hook  421  and the second hook  422 . Thus, the lower lock device  40  can simplify the configuration of the device as compare to a case where a support shaft that rotatably supports the first hook  421  and a support shaft that rotatably supports the second hook  422  are different members. 
     (5) The lower striker  26  protruding from the floor  27  is suppressed by the covering plate  28  that covers the lower striker  26 . Thus, when a user gets on and off the vehicle  10 , the user is less likely to feel the lower striker  26  as a hindrance. 
     (6) When an impact acts on the slide door  30  inward in the width direction, the engagement between the second hook  422  and the lower striker  26  can suppress displacement of the slide door  30  inward in the width direction. For example, upon a side collision with the vehicle  10 , the engagement between the second hook  422  and the lower striker  26  can suppress displacement of the slide door  30  toward the compartment, and can suppress entry of a colliding object with the vehicle  10  into the compartment. 
     Second Embodiment 
     A lower lock device  60  according to a second embodiment will be described below in detail. In the second embodiment, a configuration common to the first embodiment has the same reference sign, and description is omitted or simplified. Furthermore, since a shape and an arrangement of a constituent member are slightly different from those of the lower lock driving device  50  according to the first embodiment, a lower lock driving device  50  according to the second embodiment has the same reference sign and description is omitted. Further, In the second embodiment, the lower lock device  60  corresponds to one example of a “vehicular door lock device”. 
     As illustrated in  FIGS. 13 and 14 , the lower lock device  60  includes a base  61  assembled to a slide door  30 , a first hook  621  and a second hook  622  that engage with a lower striker  26 , and a driving link  63  that drives the first hook  621  and the second hook  622 . Further, the lower lock device  60  includes a first link  641  that couples the first hook  621  and the driving link  63 , a second link  642  that couples the second hook  622  and the driving link  63 , a first pole  651  and a second pole  652  that respectively engage with the first hook  621  and the second hook  622 , a coupling lever  66  that operates together with the first pole  651  and the second pole  652 , and a release lever  67  that drives the coupling lever  66 . 
     Further, the lower lock device  60  includes a driving link biasing spring  681  that biases the driving link  63 , a pole biasing spring  682  that indirectly biases the first pole  651  and the second pole  652 , and a release lever biasing spring  683  that biases the release lever  67 . Further, the lower lock device  60  includes a first support shaft  691  as one example of a “support shaft” that rotatably supports both of the first hook  621  and the second hook  622 , a second support shaft  692  that rotatably supports the driving link  63 , third support shafts  693  and  694  that respectively rotatably support the first pole  651  and the second pole  652 , and a fourth support shaft  695  that rotatably supports the release lever  67 . Furthermore, the lower lock device  60  includes a first coupling shaft  696  that relatively rotatably couples the first hook  621  and the first link  641 , a second coupling shaft  697  that relatively rotatably couples the driving link  63 , the first link  641 , and the second link  642 , and a third coupling shaft  698  that relatively rotatably couples the second hook  622  and the second link  642 . 
     As illustrated in  FIGS. 13 and 14 , the base  61  includes a first base  611  and a second base  612  having a flat plate shape. The first base  611  extends in a direction intersecting the second base  612  from the second base  612 . Thus, the base  61  has a substantially L shape in a plan view from above. The first base  611  is fixed to the slide door  30  via a fastening member such as a bolt. The second base  612  is coupled to the lower lock driving device  50  via a fastening member such as a bolt. 
     As illustrated in  FIG. 14 , the first hook  621  and the second hook  622  are a plate-shaped member having a substantially fan shape in a front view. The first hook  621  and the second hook  622  are disposed on a lower end portion of the first base  611  by the first support shaft  691  having the front-rear direction as a shaft direction. In other words, a rotational shaft line of the first hook  621  and the second hook  622  extends in the front-rear direction. 
     In the first hook  621 , when a portion supported by the first support shaft  691  and the first coupling shaft  696  is assumed to be a base end portion, the first hook  621  includes an engagement claw  623  and a recessed portion  624  on a tip portion. The engagement claw  623  extends in a rotational direction of the first hook  621 , and the recessed portion  624  is recessed in an opposite direction to the direction in which the engagement claw  623  extends. Further, the first hook  621  includes, on an end surface opposite to an end surface provided with the engagement claw  623  in the rotational direction of the first hook  621 , a regulation surface  625  intersecting a circumferential direction. Similarly, in the second hook  622 , when a portion supported by the first support shaft  691  and the third coupling shaft  698  is assumed to be a base end portion, the second hook  622  includes an engagement claw  623  and a recessed portion  624  on a tip portion. Further, the second hook  622  includes, on an end surface opposite to an end surface provided with the engagement claw  623  in a rotational direction of the second hook  622 , a regulation surface  625  intersecting the circumferential direction. 
     The first hook  621  and the second hook  622  rotate about a shaft line of the first support shaft  691  between an engaged position of sandwiching the lower striker  26  by bringing the tip portions closer to each other and a retracted position in which the tip portions are separated from each other. In the present embodiment, when the first hook  621  and the second hook  622  rotate between the engaged position and the retracted position, the first hook  621  and the second hook  622  have a positional relationship having substantial line symmetry with respect to a straight line passing through the center of the first support shaft  691  and extending in the up-down direction in  FIG. 14 . Further, when the first hook  621  and the second hook  622  are located in the engaged position, the lower striker  26  fits into the recessed portion  624  of the first hook  621  and the second hook  622 . 
     As illustrated in  FIGS. 13 and 14 , the driving link  63  is disposed on an upper portion of the first base  611  by the second support shaft  692  having the front-rear direction as a shaft direction. As illustrated in  FIG. 14 , the driving link  63  includes a first portion  631  and a second portion  632  extending in a direction that intersects the shaft direction of the second support shaft  692 . A tip of the first portion  631  is rotatably coupled to the first link  641  and the second link  642  via the second coupling shaft  697 . The second portion  632  extends toward the second base  612 . The driving link  63  corresponds to one example of a “driving body”. 
     As illustrated in  FIG. 14 , the first link  641  constitutes a four-joint link mechanism together with the driving link  63 , the first base  611 , and the first hook  621 . In the four-joint link mechanism including the first link  641 , a distance between shaft lines of the first support shaft  691  and the second support shaft  692  is longer than a distance between shaft lines of the first coupling shaft  696  and the second coupling shaft  697 . Further, a distance between shaft lines of the first support shaft  691  and the first coupling shaft  696  and a distance between shaft lines of the second support shaft  692  and the second coupling shaft  697  are shorter than the distance between the shaft lines of the first coupling shaft  696  and the second coupling shaft  697 . The first link  641  corresponds to a so-called intermediate link, and transmits power of the driving link  63  to the first hook  621 . 
     On the other hand, the second link  642  constitutes a four-joint link mechanism together with the driving link  63 , the first base  611 , and the second hook  622 . In the four-joint link mechanism including the second link  642 , the distance between the shaft lines of the first support shaft  691  and the second support shaft  692  is longer than a distance between shaft lines of the second coupling shaft  697  and the third coupling shaft  698 . Further, a distance between shaft lines of the first support shaft  691  and the third coupling shaft  698  and a distance between shaft lines of the second support shaft  692  and the second coupling shaft  697  are shorter than the distance between the shaft lines of the second coupling shaft  697  and the third coupling shaft  698 . The second link  642  corresponds to a so-called intermediate link, and transmits power of the driving link  63  to the second hook  622 . 
     The four-joint link mechanism including the first link  641  and the four-joint link mechanism including the second link  642  share the driving link  63 . Thus, when the driving link  63  rotates, the first hook  621  and the second hook  622  rotate together. Further, when one of the first hook  621  and the second hook  622  rotates, the other of the first hook  621  and the second hook  622  rotates with the driving link  63 . In other words, the first hook  621 , the second hook  622 , the driving link  63 , the first link  641 , and the second link  642  operate with each other. Therefore, when a position of the driving link  63  is determined, positions of the first hook  621  and the second hook  622  are also uniquely defined. 
     In the following description, it is assumed that a position of the driving link  63  when the first hook  621  and the second hook  622  are disposed in the engaged position is a “first position”, and a position of the driving link  63  when the first hook  621  and the second hook  622  are disposed in the retracted position is a “second position”. Further, the driving link  63  is displaced between the first position and the second position by rotating about the shaft line of the second support shaft  692 . 
     As illustrated in  FIGS. 13 and 14 , the first pole  651  and the second pole  652  are each disposed on an intermediate portion of the first base  611  by the third support shafts  693  and  694  having the front-rear direction as a shaft direction. 
     As illustrated in  FIG. 14 , the first pole  651  includes a first engagement piece  653  and a second engagement piece  654  extending in a direction that intersects the shaft direction of the third support shaft  693 . In the first pole  651 , the first engagement piece  653  extends toward the first hook  621 , and the second engagement piece  654  extends toward the second base  612 . The second engagement piece  654  of the first pole  651  includes a guide hole  655  that penetrates a tip. 
     Similarly, the second pole  652  includes a first engagement piece  653  and a second engagement piece  654  extending in a direction that intersects the shaft direction of the third support shaft  694 . In the second pole  652 , the first engagement piece  653  extends toward the second hook  622 , and the second engagement piece  654  extends in a direction away from the second base  612 . The second engagement piece  654  of the second pole  652  includes a guide hole  655  that penetrates a tip. 
     As illustrated in  FIG. 14 , the coupling lever  66  is disposed on the intermediate portion of the first base  611  in the up-down direction by the third support shaft  694 . In other words, a rotational shaft line of the coupling lever  66  coincides with a rotational shaft line of the second pole  652 . The coupling lever  66  includes a first lever  661  and a second lever  662  extending in a direction that intersects the shaft direction of the third support shaft  694 . The first lever  661  extends in a direction farther from the second base  612 , and the second lever  662  extends toward the second base  612 . 
     The first lever  661  includes, on the tip, a guide shaft  663  extending in a shaft direction of the third support shaft  694 . The guide shaft  663  is inserted through the guide hole  655  of the first pole  651  and the second pole  652 . Thus, when the coupling lever  66  rotates, the first pole  651  and the second pole  652  rotate. Specifically, when the coupling lever  66  rotates in a direction in which the second lever  662  rises, the first pole  651  rotates in a direction in which the first engagement piece  653  moves farther from the first hook  621 , and the second pole  652  rotates in a direction in which the first engagement piece  653  moves farther from the second hook  622 . 
     As illustrated in  FIG. 13 , the release lever  67  is disposed on a lower portion of the second base  612  by the fourth support shaft  695  having the width direction as a shaft direction. The release lever  67  includes a first lever  671  and a second lever  672  extending in a direction that intersects the shaft direction of the fourth support shaft  695 . The first lever  671  extends toward the first base  611 , and the second lever  672  extends along the first base  611 . A rear end of a third cable  383 F extending from a remote control  37 F is fixed to a tip of the second lever  672 . When the third cable  383 F is pulled, the release lever  67  rotates in a direction in which a tip of the first lever  671  rises. 
     As illustrated in  FIG. 14 , the driving link biasing spring  681  is a so-called torsion coil spring. The driving link biasing spring  681  has one end engaged with the first base  611 , and has another end engaged with the second portion  632  of the driving link  63 . The driving link biasing spring  681  biases the driving link  63  in a direction in which the driving link  63  rotates from the first position toward the second position. As described above, in the lower lock device  60 , when the driving link  63  rotates, the first hook  621  and the second hook  622  rotate, and thus it can also be said that the driving link biasing spring  681  biases both of the first hook  621  and the second hook  622 . In this respect, the driving link biasing spring  681  can replace the configuration in which the first hook  621  is biased, and can also replace the configuration in which the second hook  622  is biased. 
     As illustrated in  FIG. 14 , the pole biasing spring  682  is a so-called torsion coil spring. The pole biasing spring  682  has one end engaged with the engagement piece  613  integral with the first base  611 , and has another end engaged with the first lever  661  of the coupling lever  66 . The pole biasing spring  682  biases the coupling lever  66  in a direction in which the second lever  662  of the coupling lever  66  is lowered. In other words, the pole biasing spring  682  biases the first pole  651  in a direction in which the first engagement piece  653  of the first pole  651  pushes the first hook  621 , and biases the second pole  652  in a direction in which the first engagement piece  653  of the second pole  652  pushes the second hook  622 , via the coupling lever  66 . 
     As illustrated in  FIG. 13 , the release lever biasing spring  683  is a so-called torsion coil spring. The release lever biasing spring  683  has one end engaged with a support plate  51  of the lower lock driving device  50 , which will be described later, and has another end engaged with the second lever  672  of the release lever  67 , while the fourth support shaft  695  is inserted. As illustrated in  FIG. 14 , the release lever biasing spring  683  biases the release lever  67  in a direction in which the tip of the first lever  671  moves away from the second lever  662  of the coupling lever  66 . 
     In the present embodiment, one example of a “vehicular door lock system” including the lower lock device  60 , the lower lock driving device  50 , the lower striker  26 , and a covering plate  28  described above is constituted. 
     Action of the present embodiment will be described. 
     Specifically, with reference to  FIGS. 15 to 20 , action of the lower lock device  60  during a close operation and an open operation of the slide door  30  will be described. 
     In a vehicle  10 , when there is a request for the close operation of the slide door  30  from a user, door driving units  24 F and  24 R are driven, and the close operation of the slide door  30  starts. When the slide door  30  performs the close operation to the vicinity of a full closed position, a front lock driving device  36 F and a rear lock driving device  36 R are driven instead of the door driving units  24 F and  24 R. As a result, a front lock device  34 F and a rear lock device  34 R shift to an engagement state, and the slide door  30  is disposed in the full closed position in which the slide door  30  fully closes a door opening  21 . 
     When the slide door  30  is disposed in the full closed position, a rear end portion of a first slide door  30 F and a front end portion of a second slide door  30 R are located the closest to each other. Thus, a latch  351  of a center lock device  35 F of the first slide door  30 F engages with a center striker  35 R of the second slide door  30 R. In other words, when the slide door  30  is disposed in a full open position, the center lock device  35 F also shifts to the engagement state. 
     After the slide door  30  is disposed in the full closed position, the lower lock driving device  50  is driven. Specifically, a driving unit  56  is driven, and thus an active lever  53  rotates in a direction indicated by a solid line arrow in  FIG. 15 . Then, a close lever  55  rises in a direction indicated by a solid line arrow in  FIG. 16 , and the close lever  55  pushes the second portion  632  of the driving link  63  upward. As a result, the driving link  63  rotates in a first rotational direction R 1  from the second position, and power is transmitted to the first hook  621  and the second hook  622  via the first link  641  and the second link  642 . 
     As illustrated in  FIGS. 17 and 18 , when the close lever  55  rises the highest, the driving link  63  is disposed in the first position. When the driving link  63  is disposed in the first position, the first hook  621  and the second hook  622  are located in the engaged position of sandwiching the lower striker  26 . In this way, a movement of the lower portion of the slide door  30  in the width direction is restricted, and an attitude of the slide door  30  in the full closed position is stable. Further, when the driving link  63  rotates in the first rotational direction R 1 , the driving link biasing spring  681  is extended. 
     As illustrated in  FIG. 18 , when the driving link  63  is disposed in the first position, the first engagement piece  653  of the first pole  651  engages with the regulation surface  625  of the first hook  621 , and the first engagement piece  653  of the second pole  652  engages with the regulation surface  625  of the second hook  622 . In other words, it is impossible for the first hook  621  and the second hook  622  to rotate toward the retracted position, and it is impossible for the driving link  63  to rotate toward the second position. 
     Furthermore, when the first hook  621  and the second hook  622  are disposed in the engaged position, the first hook  621  brings the lower striker  26  relatively into the width direction, and thus the first hook  621  brings the lower portion of the slide door  30  inward in the width direction. Thus, as illustrated in  FIGS. 16 and 18 , a position of the lower portion of the slide door  30  when the first hook  621  and the second hook  622  are disposed in the engaged position is located inward in the width direction further than a position of the lower portion of the slide door  30  when the first hook  621  and the second hook  622  are disposed in the retracted position. 
     After the driving link  63  is disposed in the first position, the driving unit  56  of the lower lock driving device  50  is driven, and thus the active lever  53  rotates in a direction indicated by a solid line arrow in  FIG. 17 . In other words, the close lever  55  is lowered in a direction indicated by a solid line arrow in  FIG. 18 , and the close lever  55  is separated from the second portion  632  of the driving link  63 . Herein, the first hook  621  and the second hook  622  are in a state where the first pole  651  and the second pole  652  make it impossible for the first hook  621  and the second hook  622  to rotate toward the retracted position. Thus, even after the driving link  63  is separated from the active lever  53 , the first hook  621  and the second hook  622  remain in the engaged position. In other words, the driving link  63  also remains in the first position. 
     Subsequently, when there is a request for the open operation of the slide door  30  from a user, the front lock driving device  36 F and the rear lock driving device  36 R are driven. As a result, the front lock device  34 F and the rear lock device  34 R shift to the release state, and the center lock device  35 F and the lower lock device  60  shift to the release state. 
     As illustrated in  FIG. 19 , in the lower lock device  60 , the remote control  37 F pulls the third cable  383 F in a direction indicated by a solid line arrow, and thus the release lever  67  rotates in a direction indicated by a solid line arrow. In other words, as illustrated in  FIG. 20 , the tip of the first lever  671  of the release lever  67  rises, and the first lever  671  of the release lever  67  pushes up the second lever  662  of the coupling lever  66 . Then, the first lever  661  of the coupling lever  66  pushes down the second engagement piece  654  of the first pole  651  and the second engagement piece  654  of the second pole  652 . As a result, the first pole  651  rotates in a direction in which the first engagement piece  653  of the first pole  651  is separated from the first hook  621 , and the second pole  652  rotates in a direction in which the first engagement piece  653  of the second pole  652  is separated from the second hook  622 . As a result, the first engagement piece  653  of the first pole  651  does not engage with the regulation surface  625  of the first hook  621 , and the first engagement piece  653  of the second pole  652  does not engage with the regulation surface  625  of the second hook  622 . 
     As described above, the driving link  63  is biased by the driving link biasing spring  681  from the second position toward the first position. Thus, after the first pole  651  and the second pole  652  do not engage with the first hook  621  and the second hook  622 , respectively, the driving link  63  rotates in a second rotational direction R 2 , and the first hook  621  and the second hook  622  rotate toward the retracted position. When the driving link  63  returns to the second position, the first hook  621  and the second hook  622  return to the retracted position. In this way, the lower lock device  60  shifts to the state illustrated in  FIGS. 16 and 17 , i.e., the release state. 
     An effect of the second embodiment will be described. The second embodiment can acquire the following effect in addition to the effects (1), (2), (4), (5), and (6) of the first embodiment. 
     (7) The lower lock device  60  includes the first pole  651  and the second pole  652  that restrict rotation of the first hook  621  and the second hook  622  to the retracted position, respectively. Thus, the lower lock device  60  can fasten the first hook  621  and the second hook  622  in the engaged position even without the lower lock driving device  50  continuing to be driven. Further, the lower lock device  60  can more firmly fasten the first hook  621  and the second hook  622  in the engaged position in a point that the lower lock device  60  includes the first pole  651  and the second pole  652  that engage with the first hook  621  and the second hook  622  disposed in the engaged position, respectively. 
     The present embodiment can be performed by making a modification as follows. The present embodiment and the following modification example can be combined as long as they are not technically inconsistent.
         Installation places of the lower striker  26  and the lower lock device  40  may be replaced. In other words, the lower lock device  40  may be disposed on the lower end portion of the door opening  21  of the vehicle body  20 , and the lower striker  26  may be installed on the lower end portion of the slide door  30 .   The driving link  43  may be constituted as a “driving body” that linearly advances and retreats in a specific direction. In this case, the lower lock device  40  may include, instead of the first link  441  and the second link  442 , a conversion mechanism for converting a linear motion of the driving body into a rotational motion of the first hook  421  and the second hook  422 .   The driving link  43  itself may be constituted as an actuator. For example, the driving link  43  may be constituted by a solenoid and the like.   A mechanism for transmitting power from the driving link  43  to the first hook  421  and the second hook  422  can be appropriately changed. For example, the power transmission mechanism may be a mechanism constituted by a plurality of gears, and may be a mechanism including a wire.   The lower lock device  40  may separately include a support shaft that supports the first hook  421  and a support shaft that supports the second hook  422 . Further, the lower lock device  40  may separately include a first driving link that drives the first hook  421  and a second driving link that drives the second hook  422 .   The lower lock device  40  may be provided on the upper portion of the slide door  30 . In this case, the lower striker  26  is an upper striker installed on the upper end portion of the door opening  21 .   The vehicle body  20  may include a lower rail disposed below the door opening  21 , and the slide door  30  may include a lower guide unit that moves in the front-rear direction along the lower rail. Also, in this case, the lower lock device  40  is in the engagement state, and thus an attitude of the lower end portion of the slide door  30  in the full closed position can be stable.   The slide door  30  may be provided on the front portion of the vehicle  10 , and may be provided on the rear portion of the vehicle  10 . In other words, a movement direction when the slide door  30  performs the open/close operations may be the width direction.   The slide door  30  may be a back door that opens and closes a door opening provided in the rear portion of the vehicle body  20 . Further, the slide door  30  may be a door that swings around a shaft line extending in the up-down direction or the front-rear direction.       

     A vehicular door lock device that solves the problem described above is a vehicular door lock device that is provided on one of a door and a vehicle body, and restrains the door to the vehicle body by engaging with a striker provided on another of the door and the vehicle body. The vehicular door lock device includes a base being fixed to one of the door and the vehicle body, a first hook and a second hook each including a base end portion being rotatably supported by the base, and a driving body that is rotatably supported by the base and drives the first hook and the second hook. The first hook and the second hook rotate between an engaged position of sandwiching the striker by tip portions being close to each other and a retracted position in which the tip portions are separated from each other. The driving body is displaced between a first position in which the first hook and the second hook are disposed in the engaged position and a second position in which the first hook and the second hook are disposed in the retracted position. 
     A conventional vehicular door lock device includes a latch including a groove that meshes with a striker. Then, the striker enters the groove of the latch due to a close operation of a door, and the latch meshes with the striker, and thus the door is restrained to a vehicle body. In this respect, in the vehicular door lock device having the configuration described above, the first hook and the second hook sandwich the striker, and thus the door is restrained to the vehicle body. In other words, in the vehicular door lock device having the configuration described above, as long as the first hook and the second hook can sandwich the striker, the door can be restrained to the vehicle body. Thus, flexibility in arrangement of the first hook and the second hook with respect to the striker is more likely to be increased. Therefore, the vehicular door lock device can restrain the door in a full closed position regardless of an installation place of the striker. 
     The vehicular door lock device described above may further include a first link that transmits power of the driving body to the first hook and constitutes a link mechanism together with the driving body and the first hook, and a second link that transmits power of the driving body to the second hook and constitutes a link mechanism together with the driving body and the second hook. 
     In the vehicular door lock device having the configuration described above, power of the driving body is transmitted to the first hook and the second hook by the link mechanism. In other words, the vehicular door lock device can achieve a power transmission mechanism for rotating the first hook and the second hook between the engaged position and the retracted position, with a simple configuration. 
     In the vehicular door lock device described above, the driving body may be biased in a direction from the first position toward the second position, and the vehicular door lock device may further include a pole that restricts displacement of the driving body to the second position by engaging with the driving body disposed in the first position. 
     The vehicular door lock device having the configuration described above can fasten the first hook and the second hook in the engaged position even without the driving body continuing to drive the first hook and the second hook. Further, the vehicular door lock device can simplify the configuration of the device in a point that the pole may be one. 
     In the vehicular door lock device described above, the first hook and the second hook may be biased in a direction from the engaged position toward the retracted position, and the vehicular door lock device may further include a first pole and a second pole that respectively restrict rotation of the first hook and the second hook to the retracted position by engaging with the first hook and the second hook disposed in the engaged position, respectively. 
     The vehicular door lock device having the configuration described above can fasten the first hook and the second hook in the engaged position even without the driving body continuing to drive the first hook and the second hook. Further, the vehicular door lock device can more firmly fasten the first hook and the second hook in the engaged position in a point that the vehicular door lock device includes the first pole and the second pole that engage with the first hook and the second hook disposed in the engaged position, respectively. 
     The vehicular door lock device described above may further include a support shaft that rotatably supports both of the first hook and the second hook. 
     The vehicular door lock device having the configuration described above can simplify the configuration of the device as compare to a case where a support shaft that rotatably supports the first hook and a support shaft that rotatably supports the second hook are different members. 
     A vehicular door lock system that solves the problem described above includes the vehicular door lock device described above, and the striker. The striker is provided on a lower end of a door opening to be opened and closed by the door in a state where a portion sandwiched between the first hook and the second hook extends in a vehicle front-rear direction. The vehicular door lock device is provided on the door in a state where a rotational shaft line of the first hook and a rotational shaft line of the second hook extend in the vehicle front-rear direction. 
     The vehicular door lock system having the configuration described above can acquire a similar operational advantageous effect to that of the vehicular door lock device described above. Further, in the vehicular door lock system, when an impact acts on the door inward in a vehicle width direction, the engagement between the hook located outward in the vehicle width direction among the first hook and the second hook and the striker can suppress displacement of the door inward in the vehicle width direction. In other words, in the vehicular door lock system, upon a side collision with the vehicle, the engagement between the hook located outward in the vehicle width direction and the striker can suppress displacement of the door toward the compartment. 
     The vehicular door lock system described above may further include a covering plate that covers the striker, and the covering plate may include a slit that exposes the striker. 
     The vehicular door lock system having the configuration described above can suppress the striker protruding from the lower end of the door opening. Thus, the vehicular door lock system can suppress a user who gets on and off the vehicle feeling the striker as a hindrance. 
     The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.