Patent Publication Number: US-11383606-B2

Title: Port locking actuator device for vehicle inlet

Description:
The disclosure of Japanese Patent Application No. JP2017-197233 filed on Oct. 10, 2017 including the specification, drawings, claims and abstract is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a port locking actuator device for a vehicle inlet, the port locking actuator device enabling a locking pin driving mechanism of the port locking actuator device to be provided with a simple configuration. 
     BACKGROUND ART 
     In each of electric vehicles (including plug-in hybrid vehicles, etc.), a vehicle inlet is a charging port equipped in the vehicle in order to charge drive power from external power supply equipment to an in-vehicle power storage device (which refers to any of secondary batteries and other power storage function-equipped elements and devices in general) via a contact charging method. In other words, a charging connector at a distal end of a charging cable of the external power supply equipment is removably connected to the vehicle inlet and power is charged from the external power supply equipment to the in-vehicle power storage device passing sequentially through the charging cable, the charging connector and the vehicle inlet, etc. In order to prevent the charging connector from being mistakenly removed during charging, the vehicle inlet is equipped with a port locking actuator device. The port locking actuator device electrically locks connection between the vehicle inlet and the charging connector (that is, prevents disconnection) and unlocks the connection (that is, enables disconnection). Locking/unlocking is performed by reversibly displacing a locking displaceable element having an appropriate configuration (e.g., a locking pin) to a locked position and an unlocked position. In other words, the locking displaceable element engages with the part of the connection between the vehicle inlet and the charging connector at the locked position to prevent cancellation of the connection between the vehicle inlet and the charging connector (locked state). Also, the locking displaceable element is retracted from the part of the connection between the vehicle inlet and the charging connector at the unlocked position to allow cancellation of the connection between the vehicle inlet and the charging connector (unlocked state). 
     Examples of conventional port locking actuator devices are disclosed in Patent Literatures 1 to 4 indicated below. Each of the port locking actuator devices described in Patent Literatures 1 to 4 acts on a latch disposed at a charging connector to prevent a latched state (state of hooking the latch) from being cancelled mistakenly. The latch is intended to hold connection of the charging connector to a vehicle inlet by engaging a claw of the latch with an engagement protrusion (latch engagement portion) formed at an outer peripheral surface of a vehicle inlet from the outer circumferential side (that is, prevent the charging connector from being pulled off from the vehicle inlet, by hooking the latch). The latch is retracted outwardly by operating (pressing) a latch release button (latch release operation section) provided at the charging connector. Consequently, the claw of the latch is disengaged from the engagement protrusion, enabling the charging connector to be pulled off from the vehicle inlet. 
     Each of the port locking actuator devices described in Patent Literatures 1 to 4 includes a locking pin (locking displaceable element) and a locking pin driving mechanism. When performing charge, the locking pin driving mechanism electrically makes the locking pin project in an axis direction of the locking pin to displace the locking pin to a position adjacent to a back surface of the latch (locked position). Consequently, even if the latch release button is mistakenly operated during charging, the latch cannot be retracted outward because of the latch coming into abutment with the locking pin and the latch is thus prevented from being removed from the engagement protrusion. In other words, the connection between the charging connector and the vehicle inlet is locked. Also, after an end of the charging, the locking pin driving mechanism electrically retracts the locking pin in the axis direction of the locking pin to displace the locking pin at a position retracted from the back surface of the latch (unlocked position). Consequently, the charging connector can be removed from the vehicle inlet by operating the latch release button to retract the latch outwardly and thereby remove the latch from the engagement protrusion. In other words, the connection between the charging connector and the vehicle inlet is unlocked. 
     Citation List 
     Patent Literature 
     Patent Literature 1: Japanese Patent No. 5926173 
     Patent Literature 2: Japanese Patent Laid-Open No. 2012-209098 
     Patent Literature 3: Japanese Patent Laid-Open No. 2014-118693 
     Patent Literature 4: Japanese Patent Laid-Open No. 2014-120421 
     SUMMARY OF INVENTION 
     Technical Problem 
     There are various styles of disposition of the locking pin relative to a direction of insertion/removal of the charging connector to/from the vehicle inlet (the direction corresponding to a direction along a center axis of at least a distal end of the vehicle inlet). For example, in the port locking actuator device described in Patent Literature 1, the axis of the locking pin is disposed in a direction horizontal and perpendicular to the insertion/removal direction of the charging connector. Also, in each of the port locking actuator devices described in Patent Literatures 2 and 3, the axis of the locking pin is disposed in a direction vertical and perpendicular to the insertion/removal direction of the charging connector. Also, in the port locking actuator device described in Patent Literature 4, the axis of the locking pin is disposed in a direction parallel to the insertion/removal direction of the charging connector. 
     The latch of the charging connector is disposed at an upper portion of the charging connector at a center in a width direction in a section orthogonal to the axis of the distal end of the charging connector. Therefore, with the manner of disposition of the locking pin described in Patent Literature 1, in order to displace the locking pin in the width direction to bring the locking pin to the position of the latch, inevitably, the locking pin needs to be long and an amount of displacement of the locking pin between the locked position and the unlocked position needs to be large. Also, with the manner of disposition of the locking pin described in each of Patent Literatures 2 and 3, the axis of the locking pin is disposed in the vertical direction at a position close to the distal end of the vehicle inlet to displace the locking pin in the vertical direction. As a result, a dimension in the vertical direction of the port locking actuator device inevitably becomes large at the position close to the distal end of the vehicle inlet. Therefore, where a space for disposition of the port locking actuator device, the space being wide in the vertical direction, cannot be secured at the position close to the distal end of the vehicle inlet, this manner of disposition cannot be employed. 
     On the other hand, with a manner of disposition of the locking pin described in Patent Literature 4, the aforementioned problems in the disposed positions of the locking pins described in Patent Literatures 1 to 3 hardly occur. However, the locking pin driving mechanism described in Patent Literature 4 needs a complex configuration using a cam. 
     The present invention relates to a port locking actuator device having a structure in which an axis of a locking pin is disposed in a direction parallel to an insertion/removal of a charging connector, like the port locking actuator device described in Patent Literature 4. The present invention solves the aforementioned problem in the port locking actuator device described in Patent Literature 4 and enables a locking pin driving mechanism to be provided with a simple configuration by eliminating the need for a cam. The present invention also solves a new problem accompanied by eliminating the need for a cam. 
     Solution to Problem 
     A port locking actuator device according to the present invention is a port locking actuator device for locking a state in which a charging connector is connected to a vehicle inlet that allows the charging connector to be removably connected thereto, the port locking actuator device being installed at the vehicle inlet, wherein: the charging connector and the vehicle inlet include a latch device that inhibits or allows pull-out of the charging connector connected to the vehicle inlet; the latch device includes a latch and a latch release operation section included in the charging connector and a latch engagement portion included in an outer peripheral surface of the vehicle inlet; the latch device inhibits pull-out of the charging connector by the latch being engaged with the latch engagement portion from an outer peripheral side of the vehicle inlet with the charging connector connected to the vehicle inlet, and allows pull-out of the charging connector by the latch release operation section being operated to retract the latch outwardly from that state and the engagement being thereby cancelled; the port locking actuator device includes a locking pin and a locking pin driving mechanism; the locking pin driving mechanism electrically makes the locking pin project in an insertion/removal direction of the charging connector to dispose the locking pin at a predetermined locked position adjacent to a back surface of the latch and thereby inhibits the latch from being retracted outwardly, and electrically retracts the locking pin in the insertion/removal direction of the charging connector from that state to dispose the locking pin at a predetermined unlocked position retracted from the back surface of the latch and thereby allows the latch to be retracted outwardly; the locking pin driving mechanism include a motor, a preceding gear to be driven by the motor, a round gear that meshes with the preceding gear, a feed screw coaxially fixed to the round gear, and a slider threadably connected to the feed screw; the locking pin is mounted in the slider; a center axis of the locking pin and a center axis of the feed screw are each disposed in parallel with a center axis of the vehicle inlet that is parallel to the insertion/removal direction of the charging connector; and a positional relationship between the feed screw and the locking pin relative to the vehicle inlet is set in such a manner that an interaxial distance between the center axis of the vehicle inlet and the center axis of the feed screw is larger than an interaxial distance between the center axis of the vehicle inlet and the center axis of the locking pin. 
     The present invention enables the locking pin driving mechanism to be provided with a simple configuration by eliminating the need for a cam. Here, in a locking pin driving mechanism, in order to obtain a driving force necessary for displacing a locking pin, there is a demand for forming a round gear so as to have a large diameter to obtain a large reduction ratio. However, where a center axis of a feed screw (that is, a center axis of the round gear) is disposed in parallel with a center axis of a vehicle inlet as with the present invention, if the round gear is formed so as to have a large diameter, a new problem of the round gear interfering with an outer sleeve of the vehicle inlet occurs. Disposing the locking pin and the round gear at respective positions that are outwardly away from the outer sleeve of the vehicle inlet enables forming the round gear so as to have a large diameter without interfering with the outer sleeve of the vehicle inlet. However, where a distance between the vehicle inlet center axis and the locking pin is specified in a standard, such disposition cannot be employed. Also, a driving force necessary for displacing the locking pin can be obtained by increasing the number of gears between a motor and the round gear instead of forming the round gear so as to have a large diameter. However, in such case, the number of gears is increased, resulting in complexity in configuration. Therefore, in the present invention, the positional relationship between the feed screw and the locking pin relative to the vehicle inlet is set in such a manner that the interaxial distance between the center axis of the vehicle inlet and the center axis of the feed screw is larger than the interaxial distance between the center axis of the vehicle inlet and the center axis of the locking pin. Consequently, the round gear can be formed so as to have a large diameter without interfering with the outer sleeve of the vehicle inlet. As a result, the number of gears between the motor and the round gear can be made small by setting a large reduction ratio between the round gear and the preceding gear meshing with the round gear, enabling the electrical driving mechanism for the locking pin to be provided with a simpler configuration. Note that although each of the locking pin driving mechanisms described in Patent Literatures 1 to 4 includes a spur gear or a worm wheel as the round gear, with the disposition of the round gear in Patent Literatures 1 to 4, even if the round gear is formed so as to have a large diameter, no problem of the round gear interfering with the outer sleeve of the vehicle inlet occurs. The problem of the round gear interfering with the outer sleeve of the vehicle inlet occurs only with the disposition of the round gear in the present invention. Also, according to the present invention, the locking pin and the feed screw are disposed non-coaxially, and thus, unlike a case where a locking pin and a feed screw are disposed coaxially, the locking pin can be displaced so as to pass the feed screw (that is, respective areas in the axis directions of the locking pin and the feed screw overlap each other). Consequently, a design that makes a total length of an assembled component of the locking pin, the slider and the feed screw short becomes possible, enabling a decrease in dimension of the port locking actuator device in the axis direction of the locking pin and the feed screw. As a result, even if a space for disposing the port locking actuator device is small in a direction along the center axis of the vehicle inlet, the port locking actuator device can easily be disposed. 
     In the present invention, it is possible that the locking pin is mounted in the slider so as to orient toward a direction opposite to a direction from the slider toward the round gear. Accordingly, the locking pin can be disposed without interfering with the round gear. 
     In the present invention, it is possible that the locking pin is disposed at a position at which the center axis of the locking pin falls within a plane of the round gear. Accordingly, the interaxial distance between the locking pin and the feed screw is short in comparison with a case where a locking pin is disposed at a position at which a center axis of the locking pin falls outside a plane of a round gear. Consequently, a section, in a direction orthogonal to the center axis of the feed screw, of the slider can be made small, enabling forming the slider so as to have a smaller size. Furthermore, the locking pin can be disposed at a position at which an entire diameter of the locking pin falls within the plane of the round gear. Consequently, the interaxial distance between the locking pin and the feed screw becomes shorter, enabling the section, in the direction orthogonal to the center axis of the feed screw, of the slider to be further smaller. Therefore, the slider can be formed so as to have a further smaller size. 
     In the present invention, it is possible that in a plane orthogonal to the respective center axes of the vehicle inlet, the locking pin and the feed screw, respective positions of the three center axes are aligned on a straight line. Here, it is assumed that a position of the center axis of the feed screw is disposed off a straight line connecting the center axis of the vehicle inlet and the center axis of the locking pin with the interaxial distance between the vehicle inlet and the locking pin and the interaxial distance between the locking pin and the feed screw kept at respective fixed values. In this case, the interaxial distance between the vehicle inlet and the feed screw is inevitably short in comparison with a case where the position of the center axis of the feed screw is disposed on the straight line. As a result, the round gear becomes closer to, and thus easily interfere with, the outer sleeve of the vehicle inlet. In order to avoid the interference, it is necessary to make the round gear have a small diameter. Accordingly, aligning the respective center axes of the vehicle inlet, the locking pin and the feed screw on a straight line can be considered advantageous for making the round gear have a large diameter. 
     In the present invention, it is possible that the preceding gear is a gear directly coupled to the motor. Accordingly, only one preceding gear is interposed between the motor and the round gear, enabling the electrical driving mechanism for the locking pin to be provided with a simple configuration. In the present invention, it is possible that each of the preceding gear and the round gear is a spur gear. Accordingly, a rotation axis of the motor can be disposed in parallel with the center axis of the locking pin and the center axis of the feed screw, enabling forming the port locking actuator device so as to have a flattened shape in entirety. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a right side view illustrating a state in which a charging connector is connected to a vehicle inlet equipped with a port locking actuator device according to an embodiment of the present invention and the connection is locked. 
         FIG. 2  is a perspective diagram of the port locking actuator device according to the embodiment of the present invention as viewed obliquely from the right upper front side. A manual operation element is illustrated in an intermediate position in a rotation range and a locking pin is illustrated in an unlocked position, respectively. Illustration of a part of the device, the part being attached to a vehicle inlet outer sleeve, is omitted. 
         FIG. 3A  is a front view of the port locking actuator device illustrated in  FIG. 2 . 
         FIG. 3B  is a plan view of the port locking actuator device. 
         FIG. 3C  is a right side view of the port locking actuator device. 
         FIG. 4  is an arrow A-A sectional view of  FIG. 3B . 
         FIG. 5  is an exploded perspective diagram of the port locking actuator device illustrated in  FIG. 2 . 
         FIG. 6  is a plan view of the lower housing illustrated in  FIG. 5  alone and illustrates an inner surface of the lower housing. 
         FIG. 7A  is a bottom view of the upper housing illustrated in  FIG. 5  alone and illustrates an inner surface of the upper housing. 
         FIG. 7B  is a plan view of the upper housing alone and illustrates an outer surface of the upper housing alone. 
         FIG. 8A  is a plan view of the operation knob illustrated in  FIG. 5  alone. 
         FIG. 8B  is a bottom view of the operation knob alone. 
         FIG. 9A  is a front view of the rotary shaft illustrated in  FIG. 5  alone. 
         FIG. 9B  is a back view of the rotary shaft alone. 
         FIG. 9C  is a plan view of the rotary shaft alone. 
         FIG. 9D  is a bottom view of the rotary shaft alone. 
         FIG. 9E  is a right side view of the rotary shaft alone. 
         FIG. 10A  is a front view of a manual operation element formed by assembling the operation knob and the rotary shaft each illustrated in  FIG. 5 . 
         FIG. 10B  is a plan view of the manual operation element. 
         FIG. 10C  is a left side view of the manual operation element. 
         FIG. 10D  is a right side view of the manual operation element. 
         FIG. 11A  is a front view of the slider illustrated in  FIG. 5  alone. 
         FIG. 11B  is a back view of the slider alone. 
         FIG. 11C  is a plan view of the slider alone. 
         FIG. 11D  is a bottom view of the slider. 
         FIG. 11E  is a left side view of the slider alone. 
         FIG. 11F  is a right side view of the slider alone. 
         FIG. 12A  is a front view of a locking displaceable element formed by assembling the slider and the locking pin each illustrated in  FIG. 5 . 
         FIG. 12B  is a back view of the locking displaceable element. 
         FIG. 12C  is a plan view of the locking displaceable element. 
         FIG. 12D  is a left side view of the locking displaceable element. 
         FIG. 12E  is a right side view of the locking displaceable element. 
         FIG. 13  is a plan view illustrating the port locking actuator device illustrated in  FIG. 2  with the upper housing and the operation knob removed and indicates a rotational angle range of the rotary shaft alone with the operation knob not assembled thereto. The rotary shaft is illustrated in a state in which the rotary shaft is mechanically stopped at an unlocked position. 
         FIG. 14  is an arrow B-B sectional view of  FIG. 3A  and indicates a rotational angle range of a manual operation element. 
         FIG. 15A  is an arrow B′-B′ sectional view of  FIG. 3A  and illustrates a state in which the manual operation element has been subjected to a locking operation. 
         FIG. 15B  is an arrow B′-B′ sectional view of  FIG. 3A  and illustrates a state in which the manual operation element has been subjected to an unlocking operation. 
         FIG. 16A  is a diagram of the vehicle inlet in  FIG. 1  as viewed in an insertion/removal direction of a charging connector, and illustrates a state in which positions of respective center axes of the vehicle inlet, the locking pin and a feed screw are arranged on a single straight line in a plane orthogonal to the three center axes. 
         FIG. 16B  is an arrow C-C sectional view of  FIG. 16A  (illustration of a lower part of the vehicle inlet is omitted). 
         FIG. 17A  is a plan view of the port locking actuator device in  FIG. 2  with the upper housing removed and illustrates a state in which the locking displaceable element has been displaced to a locked position via electrical operation. 
         FIG. 17B  is an arrow D-D sectional view of  FIG. 17A . 
         FIG. 17C  is a diagram in which a locking active surface forming projection of the manual operation element, an unlocking active surface forming projection of the manual operation element, a locking passive surface forming projection of the slider and an unlocking passive surface forming projection of the slider are superimposed on  FIG. 17B , and indicates a positional relationship among the locking active surface of the manual operation element, the unlocking active surface of the manual operation element, the locking passive surface of the slider and the unlocking passive surface of the slider. 
         FIG. 18A  is a plan view of the port locking actuator device in  FIG. 2  with the upper housing removed and illustrates a state in which the locking displaceable element has been displaced to an unlocked position via electrical operation. 
         FIG. 18B  is an arrow EE sectional view of  FIG. 18A . 
         FIG. 18C  is a diagram in which the locking active surface forming projection of the manual operation element, the unlocking active surface forming projection of the manual operation element, the locking passive surface forming projection of the slider and the unlocking passive surface forming projection of the slider are superimposed on  FIG. 18B  and indicates a positional relationship among the locking active surface of the manual operation element, the unlocking active surface of the manual operation element, the locking passive surface of the slider and the unlocking passive surface of the slider. 
         FIG. 19A  is a plan view of the port locking actuator device in  FIG. 2  with the upper housing removed and illustrates a state in which the locking displaceable element has been displaced to a locked position via manual operation. 
         FIG. 19B  is an arrow F-F sectional view of  FIG. 19A . 
         FIG. 19C  is a diagram in which the locking active surface forming projection of the manual operation element, the unlocking active surface forming projection of the manual operation element, the locking passive surface forming projection of the slider and the unlocking passive surface forming projection of the slider are superimposed on  FIG. 19B , and illustrates a positional relationship among the locking active surface of the manual operation element, the unlocking active surface of the manual operation element, the locking passive surface of the slider and the unlocking passive surface of the slider. 
         FIG. 20A  is a plan view of the port locking actuator device illustrated in  FIG. 2  with the upper housing removed and illustrates a state in which the locking displaceable element has been displaced to the unlocked position via manual operation. 
         FIG. 20B  is an arrow G-G sectional view of  FIG. 20A . 
         FIG. 20C  is a diagram in which the locking active surface forming projection of the manual operation element, the unlocking active surface forming projection of the manual operation element, the locking passive surface forming projection of the slider and the unlocking passive surface forming projection of the slider are superimposed on  FIG. 20B  and illustrates a positional relationship among the locking active surface of the manual operation element, the unlocking active surface of the manual operation element, the locking passive surface of the slider and the unlocking passive surface of the slider. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An embodiment of the present invention will be described below. Here, a case where the present invention is applied to an alternate-current normal charging system complying with the IEC standard “IEC 62196 TYPE 1” and the SAE standard “SAE J1772” will be described. Also, here, with respect to a port locking actuator device (hereinafter may be abbreviated as “actuator device”), a “front surface” refers to a surface with a distal end of a locking pin viewed at the front in a position in which the actuator device is mounted in a vehicle. Also, with respect to the actuator device, directions, top (upper or up), bottom (lower or down), left, right, front and rear, refer to directions with reference to the “front surface” of the actuator device. Also, for each of components of the actuator device, top (upper or up), bottom (lower or down), left, right, front and rear, refer to directions with reference to the “front surface” of the actuator device in a position in which the component is mounted in the actuator device (that is, the component is in the position illustrated in  FIG. 5 ). 
       FIG. 1  illustrates a state in which a charging connector is connected to a vehicle inlet and the connection is locked. Upon a charging port lid (not illustrated) provided in a body of a vehicle being opened, a charging port  12  is exposed to the outside. A vehicle inlet  14  for charging is fixedly provided in the charging port  12 . On the other hand, a charging connector  18  is provided at a distal end of a charging cable  16  connected to external power supply equipment (not illustrated). The charging connector  18  is connected to the vehicle inlet  14  so as to be removable in a direction along a center axis  14   a  of the vehicle inlet  14 . Consequently, an alternate-current voltage is supplied from the external power supply equipment to an in-vehicle charger (not illustrated) passing sequentially through the charging cable  16 , the charging connector  18  and the vehicle inlet  14 . The alternate-current voltage is converted into a direct-current voltage in the in-vehicle charger and the direct-current voltage is supplied to an in-vehicle secondary battery and the in-vehicle secondary battery is thereby charged. 
     A latch device  20  for inhibiting or allowing pull-out of the charging connector  18  connected to the vehicle inlet  14  is disposed between the vehicle inlet  14  and the charging connector  18 . In other words, the latch device  20  includes a latch  22  and a latch release operation section  24  (push button) provided in the charging connector  18 , and a latch engagement portion  26  (engagement protrusion) provided in an outer peripheral surface of the vehicle inlet  14 . The latch device  20  inhibits pull-out of the charging connector  18  from the vehicle inlet  14  by a claw  22   a  of the latch  22  being engaged with the latch engagement portion  26  from the outer peripheral side of the vehicle inlet  14 , via a spring force, in a state in which the charging connector  18  connected to the vehicle inlet  14 . Also, upon the latch release operation section  24  being pressed against the spring force in the latched state and the latch  22  being thereby retracted outwardly, the engagement is cancelled (the latch is released), allowing pull-out of the charging connector  18 . 
     In order to prevent the charging connector  18  from being removed because of the latch release operation section  24  being mistakenly operated during charging, the vehicle inlet  14  is equipped with a port locking actuator device  28 . Normally, a locking operation and an unlocking operation of the actuator device  28  are performed electrically; however, the actuator device  28  is configured so that a locking operation and an unlocking operation of the actuator device  28  can also be performed manually, as an emergency action. Therefore, for example, even if the actuator device  28  cannot be switched from a locked state to an unlocked state electrically after an end of charging because of, e.g., a failure of the actuator device  28 , the actuator device  28  can be switched from a locked state to an unlocked state manually. Consequently, the charging connector  18  can be removed from the vehicle inlet  14 . Also, when the charging connector  18  is connected to the vehicle inlet  14  in order to perform charging, the actuator device  28  may fail to be switched from an unlocked state to a locked state electrically because of, e.g., a failure of the actuator device  28 . Upon occurrence of such failure, a charging device does not start charging because the charging device cannot detect completion of locking. Even in such case, switching from an unlocked state to a locked state is performed manually to make the charging device detect completion of locking, enabling start charging. 
     The actuator device  28  is mounted on an upper surface of an outer sleeve (casing)  34  of the vehicle inlet  14  and attached and fixed to the outer sleeve  34  via screw-fastening (screw-fastening positions not illustrated). A locking pin  36  projects from a front surface of the actuator device  28 . The locking pin  36  is disposed so as to move in and out toward a connection part  30  of the connection between the vehicle inlet  14  and the charging connector  18  from a locking pin moving in-and-out hole  15  (see  FIG. 16A ) formed in a flange  14   b  at a front end of the vehicle inlet  14 . The actuator device  28  electrically locks the charging connector  18  connected to the vehicle inlet  14  (that is, prevents cancellation of the connection) and electrically unlock the charging connector  18  (that is, allows cancellation of the connection). In other words, after the charging connector  18  is connected to the vehicle inlet  14 , the actuator device  28  electrically causes the locking pin  36  to project in an insertion/removal direction of the charging connector  18  (that is, the direction along the center axis  14   a  of the outer sleeve  34  of the vehicle inlet  14 ), before a start of charging. Consequently, the actuator device  28  causes the locking pin  36  to be disposed at a locked position adjacent to a back surface of the latch  22  (that is, the position illustrated in  FIG. 1 ). As a result, even if the latch release operation section  24  is mistakenly operated, the latch  22  comes into abutment with the locking pin  36  and is thus inhibited from retracting outward. Therefore, the engagement between the latch  22  and the latch engagement portion  26  is not cancelled, and as a result, the charging connector  18  cannot be pulled out from the vehicle inlet  14 . Also, after an end of charging, the locking pin  36  is electrically retracted in the insertion/removal direction of the charging connector  18 , to dispose the locking pin  36  at an unlocked position retracted from the back surface of the latch  22  (here, the position illustrated in  FIG. 16B  at which a distal end surface of the locking pin  36  does not project from a distal end surface of the vehicle inlet  14 ). Consequently, upon the latch release operation section  24  being pressed, the latch  22  is retracted outwardly and the engagement between the latch  22  and the latch engagement portion  26  is thereby cancelled. As a result, the charging connector  18  can be pulled out from the vehicle inlet  14 . The center axis  14   a  of the vehicle inlet  14 , a center axis  36   a  of the locking pin  36  and a center axis  46   a  of a later-described feed screw  46  ( FIG. 5 ) are each disposed in parallel with the insertion/removal direction of the charging connector  18 . 
       FIGS. 2 and 3  each illustrate an overall appearance of the actuator device  28 . The actuator device  28  includes a housing  32 . The housing  32  has a substantially quadrilateral shape as a whole in plan view. The actuator device  28  has a structure in which a part (that is, a part to be disposed inside the housing  32 ) of a later-described manual driving mechanism  68  ( FIG. 5 ) and a later-described electrical driving mechanism  60  ( FIG. 5 ) are housed in a water-tight manner inside the housing  32 . An operation knob  40  of the manual driving mechanism  68  is disposed so as to be exposed in a space outside the housing  32 . The housing  32  forms a fixed portion. The fixed portion is a part that is immovable relative to the vehicle inlet  14  and displaceably supports respective movable portions such as a manual operation element  38  and a locking displaceable element  54 , which will be described later. Fixing parts (not illustrated) for fixing the actuator device  28  to the outer sleeve  34  of the vehicle inlet  14  via, e.g., screw-fastening are formed in a lower portion of the housing  32 . A locking pin projection hole  33  is formed in a center in a width direction of a front surface of the housing  32 . The locking pin  36  displaceably projects from the locking pin projection hole  33 . In other words, the locking pin  36  is disposed inside the housing  32  so as to be displaceable in the direction along the center axis  36   a  of the locking pin  36 . The direction of displacement of the locking pin  36  is a direction orthogonal to the front surface of the housing  32  and is the insertion/removal direction of the charging connector  18 . A distal end of the locking pin  36  projects forward from the front surface of the housing  32  (that is, toward the near side from the surface of the sheet of  FIG. 3A ). The locking pin  36  is driven electrically or manually to be displaced to a locked position at which the locking pin  36  projects relative to the housing  32  (that is, the position illustrated in  FIGS. 1, 17 and 19 ) and an unlocked position at which the locking pin  36  is retracted relative to the housing  32  (position illustrated in  FIGS. 2, 3, 16B, 18 and 20 ). The operation knob  40  of the manual operation element  38  is disposed at an upper surface of the housing  32 . The operation knob  40  is disposed in such a manner that the operation knob  40  can be rotated relative to the housing  32 , in a direction around a rotation axis  38   a  orthogonal to the upper surface of the housing  32 , via manual operation. The operation knob  40  can be rotated around the rotation axis  38   a  by a predetermined angle in opposite, right and left, directions relative to an intermediate position (that is, the position illustrated in  FIGS. 2 and 3 ) of a rotation range of the operation knob  40 . Here, the intermediate position of the operation knob  40  illustrated in  FIGS. 2 and 3  is a neutral position for manual operation, at which the operation knob  40  provides no instruction and no indication for locking or unlocking. Upon the operation knob  40  being turned clockwise, the locking pin  36  projects to the locked position. Upon the operation knob  40  being turned counterclockwise, the locking pin  36  retracts to the unlocked position. 
       FIG. 4  illustrates a sectional structure at the arrow A-A position in  FIG. 3B . Here, the arrow A-A position is a position in a plane extending through the rotation axis  38   a  of the manual operation element  38  and orthogonal to the center axis  36   a  of the locking pin  36 . The housing  32  is formed of an upper housing  32 A and a lower housing  32 B, which are two divisions separated from each other in a top-bottom direction. In other words, the housing  32  is formed by bonding respective peripheries of butting surfaces of the upper housing  32 A and the lower housing  32 B, the butting surfaces butting each other, together and screw-fastening the peripheries to integrate the upper housing  32 A and the lower housing  32 B. A motor  44  (direct-current motor), the feed screw  46 , a slider  48 , a rotary shaft  50 , etc., are housed in an inner space  42  of the housing  32 . The locking pin  36  is mounted in the slider  48 . The locking displaceable element  54  is formed by an assembled component of the slider  48  and the locking pin  36 . A rotation axis  44   c  of the motor  44 , the center axis (rotation axis)  46   a  of the feed screw  46  and the center axis  36   a  of the locking pin  36  each extend in a direction orthogonal to the surface of the sheet of  FIG. 4  and are disposed in parallel with one another. The feed screw  46  is driven to reversibly rotate, by the motor  44 . The slider  48  is threadably connected to the feed screw  46 . A slider receiving space  90  is formed so as to extend in a direction along the rotation axis  46   a  of the feed screw  46 , in an inner peripheral surface of the lower housing  32 B. A lower portion of the slider  48  is received in the slider receiving space  90  so as to be slidable in the extending direction of the slider receiving space  90 . An upper surface  48   c  and a lower surface  48   d  of the slider  48  are disposed between respective surfaces of the upper housing  32 A and the lower housing  32 B, the surfaces being opposed to each other, and are loosely in abutment with and supported by the respective opposed surfaces. Upon the motor  44  being driven, the feed screw  46  rotates. Along with the rotation, the locking displaceable element  54  linearly moves forward or rearward according to a direction of the rotation of the feed screw  46  along the rotation axis  46   a , with rotation in a direction around the rotation axis  46   a  inhibited. In this way, the locking pin  36  is displaced to the unlocked position and the locked position via electrical operation. 
     In  FIG. 4 , a lower end  50   a  of the rotary shaft  50  is rotatably received and supported in a recess  32 Bb formed in the inner peripheral surface of the lower housing  32 B. An upper portion of the rotary shaft  50  rotatably extends through a through-hole  32 Aa formed in the upper housing  32 A and projects to an outside space above the upper housing  32 A. In the through-hole  32 Aa, a seal packing  55  (O-ring) made of rubber is disposed between the upper housing  32 A and the rotary shaft  50 . Consequently, the inner space  42  of the housing  32  is water-tightly isolated from the outside space. The operation knob  40  is fixedly fitted to an upper end of the rotary shaft  50  via a screw  52 . The manual operation element  38  is formed of an assembly component of the rotary shaft  50  and the operation knob  40 . Upon the operation knob  40  being turned in an arbitrary direction in the direction around the rotation axis  38   a  (that is, a locking direction or an unlocking direction) from the outside of the housing  32  via manual operation, the rotary shaft  50  rotates in the same direction in the inner space  42 . At a part of the rotary shaft  50 , the part being disposed in the inner space  42 , a manual operation element-side engagement portion  70  is formed so as to project toward the slider  48 . On the other hand, at the slider  48 , a locking displaceable element-side engagement portion  72  is formed so as to project toward the rotary shaft  50 . The manual operation element-side engagement portion  70  and the locking displaceable element-side engagement portion  72  engage with each other in response to an operation of the manual operation element  38 . In other words, upon the operation knob  40  being turned, the manual operation element-side engagement portion  70  engages with the locking displaceable element-side engagement portion  72  and presses the locking displaceable element  54  in the direction along the rotation axis  46   a  of the feed screw  46 . A force of the pressing makes the feed screw  46  idle without being self-locked and the locking displaceable element  54  is thus transferred in the direction along the rotation axis  46   a  (that is, a locking direction or an unlocking direction). A lead angle of the feed screw  46  is set to an angle that prevents self-locking. In this way, the locking pin  36  is displaced to the unlocked position and the locked position via manual operation. 
       FIG. 5  illustrates the actuator device  28  dissembled into respective components. The housing  32 A and the lower housing  32 B forming the housing  32  are formed of respective single-piece moldings made of a same reinforced resin material such as a glass-fiber reinforced resin. The upper housing  32 A and the lower housing  32 B are integrated by bonding the entire peripheries of the butting surfaces of the upper housing  32 A and the lower housing  32 B together via an adhesive and fastening each of four parts in the entire peripheries via a screw  41 , and thereby form the housing  32 . The motor  44 , a gear  56 , a composite gear  58 , the locking displaceable element  54 , the rotary shaft  50 , a printed board  57 , etc., are received in the inner space  42  of the housing  32 . The motor  44 , the gear  56  and the composite gear  58  form the electrical driving mechanism  60  that reversibly displaces the locking displaceable element  54  to a locked position and an unlocked position via electrical operation. Also, the motor  44 , the gear  56 , the composite gear  58  and the slider  48  form a locking pin driving mechanism  62  that reversibly displaces the locking pin  36  to the locked position and the unlocked position via electrical operation. Each of the gear  56  and the composite gear  58  is formed of a single-piece molding made of a reinforced resin material such as a glass-fiber reinforced resin. The gear  56  (pinion) is fitted on and thereby directly coupled to a motor shaft  45  of the motor  44 . The composite gear  58  is formed by disposing a round gear  64  and the feed screw  46  coaxially. The gear  56  and the round gear  64  are each formed of a spur gear and mesh with each other. The gear  56  forms one and only preceding gear for the round gear  64  and is disposed between the motor  44  and the round gear  64 . The slider  48  is formed of a single-piece molding made of a resin such as POM (polyacetal). The slider  48  includes a female thread  115  formed so as to extend through the slider  48  in a front-rear direction. The slider  48  is threadably connected to the feed screw  46  via the female thread  115  and advances or retracts along the feed screw  46  according to a direction of rotation of the feed screw  46 . As described with reference to  FIG. 4 , the slider  48  is received in the inner space  42  so as to be unrotatable in the direction around the rotation axis  46   a  of the feed screw  46 . The locking pin  36  is formed of a straight stick (here, a straight round stick) of metal such as stainless steel. The locking pin  36  is fixed to the slider  48  with a rear end of the locking pin  36  inserted to a locking pin insertion hole  66  in a lower portion of a front surface of the slider  48 . Consequently, the slider  48  and the locking pin  36  are integrally assembled to form the locking displaceable element  54 . At this time, the center axis  36   a  of the locking pin  36  is disposed in parallel with a center axis of the female thread  115  of the slider  48  (in other words, the center axis  46   a  of the feed screw  46 ) at a position immediately below the female thread  115 . With the above arrangement, upon the motor  44  being driven, rotation of the motor shaft  45  is transmitted to the feed screw  46  via the gear  56  and the round gear  64 , and the slider  48  advances or retracts along the feed screw  46  according to a direction of rotation of the feed screw  46 . Then, upon the slider  48  advancing, the locking pin  36  is displaced to the projecting locked position, and upon the slider  48  being retracted, the locking pin  36  is displaced to the retracted unlocked position. This displacement operation is performed in such a manner that the locking pin  36  and the feed screw  46  pass each other (that is, as illustrated in, e.g.,  FIG. 16B , respective areas in the axis directions of the locking pin  36  and the feed screw  46  overlap each other). 
     In  FIG. 5 , the operation knob  40  and the rotary shaft  50  are assembled by the screw  52  to form the manual operation element  38 . Each of the operation knob  40  and the rotary shaft  50  is formed of a single-piece molding made of a reinforced resin material such as a glass-fiber reinforced resin. The manual operation element  38  is operated to be reversibly displaced in the locking direction and the unlocking direction (see  FIG. 3B ) via manual operation. The manual operation element  38  (including the manual operation element-side engagement portion  70 ) and the locking displaceable element-side engagement portion  72  of the slider  48  form the manual driving mechanism  68 . The manual driving mechanism  68  is intended to reversibly displace the locking displaceable element  54  to the locked position and the unlocked position via manual operation. A round hole  74  is formed in a front surface of the lower housing  32 B so as to extend to the inner space  42 . A seal packing  76  (O-ring) made of rubber is received and disposed on the round hole  74 . A seal packing retainer  78  is fitted and fixed to the front surface of the lower housing  32 B coaxially with the round hole  74 . Consequently, the seal packing  76  is held in the round hole  74 . The locking pin projection hole  33  is formed so as to extend through a center of a surface of the seal packing retainer  78 . The locking pin  36  is water-tightly inserted to the inner space  42  through the locking pin projection hole  33 , a center hole of the seal packing  76  and the round hole  74  of the housing  32  (see  FIG. 16B ). A circuit that supplies driving power from the outside of the actuator device  28  to the motor  44  is disposed on the printed board  57 . In other words, motor connection terminals  80   a ,  80   b  are provided at one end in a longitudinal direction of the printed board  57  and connector connection terminals (not illustrated) are provided at the other end, and wirings connecting both terminals are provided along the longitudinal direction. A seal packing  82  is attached to the other end so as to surround the connector connection terminals. The seal packing  82  is fitted and attached to a connector insertion port  32 Bc formed in the lower housing  32 B so as to water-tightly close the connector insertion port  32 Bc ( FIG. 6 ). The motor connection terminals  80   a ,  80   b  are inserted to the terminals  44   a ,  44   b  of the motor  44 , respectively. A connector at ends of wirings connected to an in-vehicle port locking actuator driving circuit (not illustrated) is inserted and connected to the connector connection terminals. 
     Major components in  FIG. 5  will be described in detail. 
     &lt;&lt;Lower Housing  32 B ( FIG. 6 )&gt;&gt; 
       FIG. 6  illustrates an inner structure of the lower housing  32 B. A motor receiving space  84 , a gear receiving space  86 , bearings  92   a ,  92   b , a round gear receiving space  88 , a slider receiving space  90 , the recess  32 Bb, the connector insertion port  32 Bc, etc., are formed in the inner space  42  of the lower housing  32 B. A lower portion of the motor  44  is received and held in the motor receiving space  84 . In the gear receiving space  86 , the gear  56  is received and disposed in so as to be not in contact with a peripheral wall surface of the gear receiving space  86 . Lower surfaces of opposite ends in an axis direction of the composite gear  58  are bearing-supported on the bearings  92   a ,  92   b . In the round gear receiving space  88 , a lower portion of the round gear  64  is received and disposed so as to be not in contact with a peripheral wall surface of the round gear receiving space  88 . In the slider receiving space  90 , the lower portion of the slider  48  threadably connected to the feed screw  46  is slidably received and disposed along a longitudinal direction of the slider receiving space  90 . Each of wall surfaces  90   a  (front end surface),  90   b  (rear end surface) of opposite ends in the longitudinal direction of the slider receiving space  90  form a locking displaceable element stopper. In other words, at the time of electrical operation of the locking displaceable element  54 , the slider  48  comes into abutment with the locking displaceable element stoppers  90   a ,  90   b  and the locking displaceable element stoppers  90   a ,  90   b  mechanically lock the locking displaceable element  54  at the locked position or the unlocked position. Among the locking displaceable element stoppers  90   a ,  90   b , the locking displaceable element stopper  90   a  stops displacement in the locking direction of the locking displaceable element  54  and the locking displaceable element stopper  90   b  stops displacement in the unlocking direction of the locking displaceable element  54 . The recess  32 Bb receives and rotatably supports the lower end  50   a  of the rotary shaft  50 . The seal packing  82  of the printed board  57  is fitted and attached to the connector insertion port  32 Bc. A butting surface  326   d  butting the upper housing  32 A is formed at an entire peripheral edge of the lower housing  32 B. A screw hole  32 Be is formed at each of four corners in the entire butting surface  32 Bd. The screws  41  for joining the upper housing  32 A and the lower housing  32 B are screwed into the respective screw holes  32 Be. 
     &lt;&lt;Upper housing  32 A ( FIGS. 7A and 7B )&gt;&gt; 
       FIG. 7A  illustrates an inner structure of the upper housing  32 A. A motor receiving space  94 , bearings  95   a ,  95   b , a round gear receiving space  96 , two rails  98 , a through-hole  32 Aa, etc., are formed in the inner space  42  of the upper housing  32 A. An upper portion of the motor  44  is received and held in the motor receiving space  94 . Upper surfaces of the opposite ends in the axis direction of the composite gear  58  are bearing-supported on the bearings  95   a ,  95   b . In the round gear receiving space  96 , an upper portion of the round gear  64  is received and disposed so as to be not in contact with a peripheral wall surface of the round gear receiving space  96 . The two rails  98  are lightly in abutment with the upper surface of the slider  48  and slidably support the slider  48  (see  FIG. 4 ). The upper portion of the rotary shaft  50  is rotatably inserted through the through-hole  32 Aa. A butting surface  32 Ab butting the lower housing  32 B is formed at an entire peripheral edge of the upper housing  32 A. A screw though-hole  32 Ac is formed at each of four corners in the entire butting surface  32 Ab. The screws  41  for joining the upper housing  32 A and the lower housing  32 B are screwed into the respective screw though-holes  32 Ac.  FIG. 7B  illustrates an outer structure of the upper housing  32 A. An annular wall  100  is formed so as to project upward at a periphery of the through-hole  32 Aa in an upper surface of the upper housing  32 A. The annular wall  100  is formed coaxially with the through-hole  32 Aa so as to surround the through-hole  32 Aa (see  FIG. 4 ). The annular wall  100  is rotatably received in an annular groove  101  ( FIG. 8B ) in a lower surface of the operation knob  40  (see  FIG. 4 ). At an outer periphery of the annular wall  100 , a manual operation element stopper forming projection  102  is formed integrally with the annular wall  100  so as to have a predetermined length in a circumferential direction. The manual operation element stopper forming projection  102  is fitted in a manual operation element-side recess  105  ( FIG. 8B ) of the operation knob  40 , which will be described next, so as to be rotatable relative to the manual operation element-side recess  105  in a predetermined angle range in the direction around the rotation axis  38   a . Consequently, the manual operation element stopper forming projection  102  restricts a rotational angle range of the manual operation element  38 . Opposite ends in the circumferential direction of the manual operation element stopper forming projection  102  form manual operation element stoppers  102   a ,  102   b . Among the manual operation element stoppers  102   a ,  102   b , the manual operation element stopper  102   a  forms a stopper for the locking direction and the manual operation element stopper  102   b  forms a stopper for the unlocking direction. 
     &lt;&lt;Operation Knob  40  ( FIGS. 8A and 8B )&gt;&gt; 
       FIG. 8A  illustrates a structure of the operation knob  40  of the manual operation element  38  in plan view. In the operation knob  40 , a handle  40   a  is provided so as to extend in a radial direction from a center of a planar surface of the operation knob  40 . A screw insertion hole  40   b  for inserting the screw  52  is formed at the center of the planar surface of the operation knob  40 .  FIG. 8B  illustrates a lower surface structure of the operation knob  40 . The annular groove  101  that rotatably receives the annular wall  100  ( FIG. 7B ) at the upper surface of the upper housing  32 A is formed in the lower surface of the operation knob  40 . An area in a circumferential direction of a wall surface  104  on the outer circumferential side forming the annular groove  101  (that is, located at an outer circumference of the annular groove  101 ) is cut out and thereby forms a manual operation element-side recess  105 . Opposite ends  105   a ,  105   b  in a circumferential direction (direction around the rotation axis  38   a ) of the manual operation element-side recess  105  are disposed at respective positions that are the same in the radial direction as the positions of the manual operation element stoppers  102   a ,  102   b  ( FIG. 7B ) of the upper housing  32 A with reference to the rotation axis  38   a  (that is, with the rotation axis  38   a  as a center). The opposite ends  105   a ,  105   b  form manual operation element stopper abutment surfaces that come into abutment with the manual operation element stoppers  102   a ,  102   b  according to a direction of rotation of the manual operation element  38 . Among the manual operation element stopper abutment surfaces, the manual operation element stopper abutment surface  105   a  forms an abutment surface for the locking direction. Also, the manual operation element stopper abutment surface  105   b  forms an abutment surface for the unlocking direction. In the direction around the rotation axis  38   a , a length in the circumferential direction of the manual operation element stopper forming projection  102  ( FIG. 7B ) is set to be shorter than a length in the circumferential direction of the manual operation element-side recess  105 . Consequently, the manual operation element stopper forming projection  102  and the manual operation element-side recess  105  are disposed in such a manner that the manual operation element stopper forming projection  102  and the manual operation element-side recess  105  are fitted to each other so as to be rotatable relative to each other in a predetermined angle range in the direction around the rotation axis  38   a  (see  FIG. 14 ). The positions in the radial direction of the manual operation element stopper abutment surfaces  105   a ,  105   b  with reference to the rotation axis  38   a  are disposed at positions on the outer circumferential side relative to a diameter of the rotary shaft  50 . Consequently, a force generated when rotation of the operation knob  40  is stopped by the manual operation element stoppers  102   a ,  102   b  is received by the operation knob  40  at a position that is relatively far from the rotation axis  38   a , which is a center of the rotation. Therefore, when the operation knob  40  is forcedly operated, the operation knob  40  can be prevented from being broken by an excessive force being applied to the operation knob  40 . Also, a force generated when rotation of the operation knob  40  is stopped by the manual operation element stoppers  102   a ,  102   b  is received by the operation knob  40  and not imposed on the rotary shaft  50 . Therefore, when the operation knob  40  is forcedly operated, the rotary shaft  50  can be prevented from being broken by large distortion occurring in the rotary shaft  50 . A rotary shaft insertion hole  40   c  that allows the upper end of the rotary shaft  50  to be unrotatably inserted thereto is formed at a center of the lower surface of the operation knob  40 . 
     &lt;&lt;Rotary Shaft  50  ( FIGS. 9A to 9E )&gt;&gt; 
       FIGS. 9A to 9E  illustrate a structure of the rotary shaft  50  of the manual operation element  38  as viewed from various directions. The lower end  50   a  of the rotary shaft  50  is rotatably received and supported in the recess  32 Bb ( FIG. 6 ) of the lower housing  32 B. The upper end  50   b  of the rotary shaft  50  is unrotatably inserted to the rotary shaft insertion hole  40   c  ( FIG. 8B ) in the lower surface of the operation knob  40 . A screw hole  50   c  ( FIG. 9C ) that allows the screw  52  ( FIG. 5 ) for fixation of the operation knob  40  to be screwed thereinto is formed at a center of a top surface of the rotary shaft  50 . A bulge  50   d  that bulges outward is formed at a center in an axis direction of the rotary shaft  50 . When the rotary shaft  50  is received in the inner space  42  of the housing  32 , the bulge  50   d  is loosely held between the upper housing  32 A and the lower housing  32 B (see  FIG. 4 ). Consequently, displacement in the axis direction (top-bottom direction) of the rotary shaft  50  relative to the housing  32  is suppressed. The manual operation element-side engagement portion  70  is formed at a side surface, between the bulge  50   d  and the lower end  50   a , of the rotary shaft  50  so as to laterally project. As described above, the manual operation element-side engagement portion  70  is intended to engage with the locking displaceable element-side engagement portion  72  ( FIG. 5 ) formed at the slider  48  and transfer the locking displaceable element  54  in the locking direction or the unlocking direction according to a manual operation of the manual operation element  38 . A configuration of the manual operation element-side engagement portion  70  will be described. The manual operation element-side engagement portion  70  includes two projections, a locking active surface forming projection  106  and an unlocking active surface forming projection  108 . The locking active surface forming projection  106  and the unlocking active surface forming projection  108  are disposed in a projecting manner with respective positions shifted to each other in two directions orthogonal to each other, the direction around the rotation axis  38   a  and a direction along the rotation axis  38   a . Opposed surfaces  106   a ,  108   a  of distal ends of the locking active surface forming projection  106  and the unlocking active surface forming projection  108  are disposed so as to face each other in the direction along the direction around the rotation axis  38   a  and be shifted from each other in the direction along the rotation axis  38   a . Also, the opposed surfaces  106   a ,  108   a  are inclined surfaces each inclined so as to face outward. The surface  106   a  forms a locking active surface that transfers the locking displaceable element  54  in the locking direction and the surface  108   a  forms an unlocking active surface that transfers the locking displaceable element  54  in the unlocking direction. 
     &lt;&lt;Manual Operation Element  38  ( FIGS. 10A to 10D )&gt;&gt; 
       FIGS. 10A to 10D  illustrate a structure of the manual operation element  38  formed by assembling the rotary shaft  50  and the operation knob  40  via the screw  52 , as viewed in various directions.  FIGS. 10A to 10D  illustrate the manual operation element  38  in a position in which the manual operation element  38  is located at an intermediate position  38 M (neutral position) in the rotational range thereof. At this time, the handle  40   a  of the operation knob  40  projects to the front side (that is, forward), the manual operation element-side engagement portion  70  (the locking active surface forming projection  106  and the unlocking active surface forming projection  108 ) projects rightward and the manual operation element-side recess  105  is disposed on the back side of the operation knob  40 . 
     &lt;&lt;Slider  48  ( FIGS. 11A to 11F )&gt;&gt; 
       FIGS. 11A to 11F  illustrate a structure of the slider  48  as viewed in various directions. The slider  48  is formed in a substantially rectangular parallelepiped shape as a whole. At a left side surface  48   e  of the slider  48 , the locking displaceable element-side engagement portion  72  is formed so as to project laterally. As described above, the manual operation element-side engagement portion  70  is engaged with the locking displaceable element-side engagement portion  72  and an operation of the manual operation element  38  is transmitted to the locking displaceable element-side engagement portion  72 . A configuration of the locking displaceable element-side engagement portion  72  will be described. The locking displaceable element-side engagement portion  72  includes two projections, a locking passive surface forming projection  111  and an unlocking passive surface forming projection  113 . The locking passive surface forming projection  111  and the unlocking passive surface forming projection  113  are disposed in a projecting manner with respective positions shifted each other in two directions, a displacement direction of the slider  48  and a top-bottom direction orthogonal to the displacement direction. Opposed surfaces  111   a ,  113   a  of the locking passive surface forming projection  111  and the unlocking passive surface forming projection  113  are disposed so as to face each other in the displacement direction of the slider  48  and be shifted from each other in the top-bottom direction. The surface  111   a  forms a locking passive surface that allows the locking active surface  106   a  to abut thereon and is thereby pressed in the locking direction. The surface  113   a  forms an unlocking passive surface that allows the unlocking active surface  108   a  to abut thereon and is thereby pressed in the unlocking direction. In addition, the female thread  115  to which the feed screw  46  threadably connected is formed in the slider  48  so as to extend through between the front end surface  48   a  and the rear end surface  48   b . The front end surface  48   a  forms a locking displaceable element stopper abutment surface that comes into abutment with the locking displaceable element stopper  90   a  ( FIG. 6 ) (abutment surface for the locking direction). The rear end surface  48   b  forms a locking displaceable element stopper abutment surface that comes into abutment with the locking displaceable element stopper  90   b  ( FIG. 6 ) (abutment surface for the unlocking direction). Furthermore, in the slider  48 , two locking pin insertion holes  66 ,  67  are formed at respective positions immediately below the female thread  115  in such a manner that the locking pin insertion holes  66 ,  67  are aligned on a straight line parallel to an axis of the female thread  115  (see  FIG. 16B ). A pair of claws  117 ,  117  facing each other are formed at respective positions between the two locking pin insertion holes  66 ,  67 . A space  118  is formed between the claws  117 ,  117 . Also, on the opposite, right and left, side of the lower surface  48   d  of the slider  48 , rails  119  are formed over an entire length of the slider  48  along the displacement direction in which the slider  48  is displaced, respectively. The slider  48  slides in the slider receiving space  90  of the lower housing  32 B with the rails  119  abutting on a bottom surface of the slider receiving space  90 . 
     &lt;&lt;Locking Displaceable Element  54  ( FIGS. 12A to 12E )&gt;&gt; 
       FIGS. 12A to 12E  illustrate a structure of the locking displaceable element  54  formed by assembling the slider  48  and the locking pin  36 , as viewed in various directions. The locking pin  36  is inserted to the locking pin insertion hole  66  ( FIG. 12A ) of the slider  48  from the rear end side of the locking pin  36  and is made to penetrate the space  118  between the claws  117 ,  117  ( FIGS. 12C and 11C ). Then, a thin portion  36   c  ( FIGS. 5 and 16B ) at a rear end of the locking pin  36  is pressed into the locking pin insertion hole  67  ( FIGS. 12B and 16B ) on the back side. Consequently, the locking pin  36  is assembled to the slider  48 . At an intermediate position in the axis direction of the locking pin  36 , a bulge  36   b  ( FIGS. 12C, 5 and 16B ) that bulges outward is formed. In a state in which the locking pin  36  is assembled to the slider  48 , the claws  117 ,  117  engage with a stepped portion at a front end of the bulge  36   b  ( FIG. 12C ). Consequently, the locking pin  36  is prevented from coming off from the slider  48  or rattling in the slider  48 , and the assembled state is stably maintained. 
     The actuator device  28  in  FIG. 5  can be assembled, for example, according to the following procedure. 
     (1) Attach the gear  56  to the motor shaft  45 . 
     (2) Threadably connect the slider  48  to the feed screw  46 . 
     (3) Put and dispose the motor  44  with the gear  56  attached thereto, the assembled component of the composite gear  58  and the slider  48  and the rotary shaft  50  at respective predetermined positions in the lower housing  32 B. 
     (4) Insert the motor connection terminals  80   a ,  80   b  at the one end of the printed board  57  to the terminals  44   a ,  44   b  of the motor  44 . Fit and attach the seal packing  82  at the other end of the printed board  57  to the connector insertion port  32 Be ( FIG. 6 ) of the lower housing  32 B. Consequently, the printed board  57  is assembled to the lower housing  32 B side.
 
(5) Fit the seal packing  76  in the round hole  74  in the front surface of the lower housing  32 B and attach the seal packing retainer  78 .
 
(6) Insert the locking pin  36  to the locking pin projection hole  33  from the rear end of the locking pin  36  and press the locking pin  36  in until the locking pin  36  butts.
 
(7) Apply an adhesive to the butting surface  32 Bd at the entire peripheral edge of the lower housing  32 B.
 
(8) Put the upper housing  32 A on the lower housing  32 B. At this time, the upper portion of the rotary shaft  50  projects to the outside space from the through-hole  32 Aa of the upper housing  32 A.
 
(9) Insert the screws  41  to the screw though-holes  32 Ac at the four corners of the upper housing  32 A, respectively, and screw the screws  41  into the screw holes  32 Be of the lower housing  32 B and fasten the screws  41  to the screw holes  32 Be. Consequently, the upper housing  32 A and the lower housing  32 B are joined.
 
(10) Fit the seal packing  55  on the upper portion of the rotary shaft  50  projecting to the outside space, put the operation knob  40  on the upper end of the rotary shaft  50 , and fasten the rotary shaft  50  and the operation knob  40  via the screw  52  to join the rotary shaft  50  and the operation knob  40 . As above, the actuator device  28  is assembled in the state illustrated in  FIGS. 2 and 3 .
 
     The rotation range of the manual operation element  38  will be described.  FIG. 13  illustrates the actuator device  28  with the operation knob  40  and the upper housing  32 A removed. At this time, restriction of the rotational angle range of the manual operation element  38  by abutment between the manual operation element stoppers  102   a ,  102   b  ( FIG. 7B ) of the upper housing  32 A and the manual operation element stopper abutment surfaces  105   a ,  105   b  ( FIG. 8B ) of the operation knob  40  is not effected. Therefore, in  FIG. 13 , upon the rotary shaft  50  being turned counterclockwise to transfer the locking displaceable element  54  in the unlocking direction (mechanism for the transfer will be described later), the locking displaceable element stopper abutment surface  48   b  formed by the rear end surface of the slider  48  comes into abutment with the locking displaceable element stopper  90   b  formed by the rear end surface of the slider receiving space  90  and the transfer of the locking displaceable element  54  is thereby stopped.  FIG. 13  illustrates a state in this case. In this case, a rotational angle of the rotary shaft  50  relative to an intermediate position  38 M in the rotation range of the manual operation element  38  is 33 degrees. Upon the rotary shaft  50  being forcedly operated further counterclockwise from this state, an excessive force is applied to the part of engagement between the rotary shaft  50  and the slider  48  (the manual operation element-side engagement portion  70  and the locking displaceable element-side engagement portion  72 ), which may cause breakage of the engagement part. Then, upon the rotary shaft  50  being turned clockwise to transfer the locking displaceable element  54  in the locking direction (mechanism for the transfer will be described later), the locking displaceable element stopper abutment surface  48   a  formed by the front end surface of the slider  48  comes into abutment with the locking displaceable element stopper  90   a  formed by the front end surface of the slider receiving space  90  and the transfer of the locking displaceable element  54  is thereby stopped. In this case, a rotational angle of the rotary shaft  50  relative to the intermediate position  38 M in the rotation range of the manual operation element  38  is also 33 degrees. Upon the rotary shaft  50  being forcedly operated further clockwise from this state, an excessive force is applied to the part of engagement between the rotary shaft  50  and the slider  48  (the manual operation element-side engagement portion  70  and the locking displaceable element-side engagement portion  72 ), which may cause breakage of the engagement part. 
     On the other hand,  FIG. 14  illustrates a positional relationship between the manual operation element stoppers  102   a ,  102   b  of the upper housing  32 A and the manual operation element stopper abutment surfaces  105   a ,  105   b  of the operation knob  40  in the actuator device  28  with the operation knob  40  and the upper housing  32 A attached thereto. Note that  FIG. 14  illustrates a sectional surface at the arrow B-B position in  FIG. 3A  and illustrates a state in which the operation knob  40  is located at the intermediate position  38 M in the rotation range. The operation knob  40  can be rotated in the locking direction until the manual operation element stopper abutment surface  105   a  abuts against and is thereby stopped by the manual operation element stopper  102   a . Also, the operation knob  40  can be rotated in the unlocking direction until the manual operation element stopper abutment surface  105   b  abuts against and is thereby stopped by the manual operation element stopper  102   b . These angles of rotation until the abutment and stoppage are 29 degrees relative to the intermediate position  38 M both in the locking direction and the unlocking direction. The rotational angle of 29 degrees in the locking direction is an angle at which the locking displaceable element  54  sufficiently reaches the locked position and a locked state by the locking pin  36  is obtained. Also, the rotational angle of 29 degrees in the unlocking direction is an angle at which the locking displaceable element  54  sufficiently reaches the unlocked position and an unlocked state by the locking pin  36  is obtained. Accordingly, when the manual operation element  38  is operated, after the locking displaceable element  54  reaching the locked position or the unlocked position, the manual operation element  38  abuts against and is thereby stopped by the manual operation element stoppers  102   a ,  102   b  before abutting against and being thereby stopped by the locking displaceable element stoppers  90   a ,  90   b  ( FIG. 13 ). Therefore, even if the manual operation element  38  is forcedly operated, no excessive force is applied to the part of engagement between the locking displaceable element  54  and the manual operation element  38  (the manual operation element-side engagement portion  70  and the locking displaceable element-side engagement portion  72 ), enabling prevention of breakage of the engagement part.  FIGS. 15A and 15B  illustrate a sectional surface at the arrow B′-B′ position in  FIG. 3A . Among the figures,  FIG. 15A  illustrates a state in which the manual operation element  38  has been operated in the locking direction and the manual operation element stopper abutment surface  105   a  has thereby abutted against and been stopped by the manual operation element stopper  102   a . Also,  FIG. 15B  illustrates a state in which the manual operation element  38  has been operated in the unlocking direction and the manual operation element stopper abutment surface  105   b  has thereby abutted against and been stopped by the manual operation element stopper  102   b.    
     A positional relationship, etc. will be described, the positional relation ship being those of among the respective axes in a state in which the actuator device  28  mounted in the vehicle inlet  14 .  FIG. 16A  illustrates the vehicle inlet  14  in  FIG. 1  as viewed in the insertion/removal direction of the charging connector  18 .  FIG. 16B  illustrates a sectional surface at the C-C arrow position in  FIG. 16A . The center axis  36   a  of the locking pin  36  and the center axis  46   a  of the feed screw  46  are each disposed in parallel with the center axis  14   a  of the vehicle inlet  14 . Also, a positional relationship between the feed screw  46  and the locking pin  36  is set in such a manner that an interaxial distance d 1  between the center axis  14   a  of the vehicle inlet  14  and the center axis  46   a  of the feed screw  46  is larger than an interaxial distance d 2  between the center axis  14   a  of the vehicle inlet  14  and the center axis  36   a  of the locking pin  36 . Although a distance d 3  between the center axis  14   a  of the vehicle inlet  14  and a lower surface of the locking pin  36  is set according to the relevant standard, since the setting is made so that d 1 &gt;d 2 , the center axis  46   a  of the feed screw  46  (=a center axis of the round gear  64 ) can be disposed away from the outer sleeve  34  of the vehicle inlet  14 . Therefore, the round gear  64  can be formed so as to have a large diameter without interfering with the outer sleeve  34  of the vehicle inlet  14  (see  FIG. 16B ), enabling setting a large reduction ratio between the round gear  64  and the gear  56  ( FIG. 5 ) meshing with the round gear  64 . Consequently, the preceding gear disposed between the round gear  64  and the motor  44  can be formed by the single gear  56  alone, enabling simple configuration of the electrical driving mechanism  60 . 
     In  FIG. 16A , the center axis  14   a  of the vehicle inlet  14 , the center axis  36   a  of the locking pin  36  and the center axis  46   a  of the feed screw  46  are parallel to one another. Also, in a plane orthogonal to these three center axes  14   a ,  36   a ,  46   a  (the surface of the sheet of  FIG. 16A ), these three center axes  14   a ,  36   a ,  46   a  are aligned on a vertical straight line L 1 . Here, it is assumed that the center axis  46   a  of the feed screw  46  is disposed at a position off the straight line L 1  with each of the interaxial distance d 2  between the vehicle inlet  14  and the locking pin  36  and an interaxial distance d 4  between the locking pin  36  and the feed screw  46  maintained at a fixed value. In this case, the interaxial distance d 1  between the vehicle inlet  14  and the feed screw  46  is necessarily short in comparison with the case where the center axis  46   a  of the feed screw  46  is disposed at a position on the straight line L 1  (disposition in  FIG. 16A ). As a result, the round gear  64  can easily come close to and interfere with the outer sleeve  34  of the vehicle inlet  14 . In order to avoid the interference, it is necessary to make the round gear  64  have a small diameter. Accordingly, aligning the center axis  14   a  of the vehicle inlet  14 , the center axis  36   a  of the locking pin  36  and the center axis  46   a  of the feed screw  46  on the single straight line L 1  can be considered advantageous for making the round gear  64  have a large diameter. 
     In  FIG. 16B , the locking pin  36  is mounted in the slider  48  so as to orient toward a direction that is opposite to a direction from the slider  48  toward the round gear  64 . Therefore, the locking pin  36  can be disposed without interfering with the round gear  64 . Also, the center axis  36   a  of the locking pin  36  is disposed at a position at which the center axis  36   a  falls within a plane of the round gear  64 . Therefore, in comparison with a case where the center axis  36   a  of the locking pin  36  is disposed at a position at which the center axis  36   a  falls outside the plane of the round gear  64 , an interaxial distance d 4  between the locking pin  36  and the feed screw  46  is short. Consequently, a section, in a direction orthogonal to the center axis  46   a  of the feed screw  46 , of the slider  48  can be reduced, enabling forming the slider  48  so as to have a smaller size. In particular, in this embodiment, the locking pin  36  is disposed at a position at which an entire diameter D of the locking pin  36  falls within the plane of the round gear  64 , and thus, the section, in the direction orthogonal to the center axis  46   a  of the feed screw  46 , of the slider  48  can be made to be further smaller. Therefore, the slider  48  can be formed so as to have a further smaller size. 
     A locking operation and an unlocking operation of the actuator device  28  by electrical operation and manual operation will be described, respectively. 
     &lt;&lt;Locking Operation by Electrical Operation ( FIGS. 17A to 17C )&gt;&gt; 
       FIGS. 17A to 17C  illustrate a state in which the locking displaceable element  54  has been displaced to the locked position via electrical operation. The locking operation by electrical operation is performed by applying a direct-current voltage for the locking direction from the in-vehicle port locking actuator driving circuit (not illustrated) to the motor  44  for a predetermined set length of time (that is, a length of time sufficient for electrically displacing the locking displaceable element  54  from the unlocked position to the locked position). Upon the motor  44  being driven by the application of the direct-current voltage, the locking displaceable element  54  is transferred in the locking direction, and along with the transfer, the locking pin  36  projects from the housing  32 . During the transfer of the locking displaceable element  54 , the locking active surface  106   a  and the unlocking passive surface  113   a  pass each other and the unlocking active surface  108   a  and the locking passive surface  111   a  pass each other. Upon the locking displaceable element stopper abutment surface  48   a  (front end surface of the slider  48 ) abutting against the locking displaceable element stopper  90   a  (front end surface of the slider receiving space  90 ), the locking displaceable element  54  is mechanically stopped (state illustrated in  FIGS. 17A to 17C ). After the locking displaceable element  54  being mechanically stopped at the locked position, the power supply to the motor  44  is stopped because of elapse of the set length of time of the application and the locking displaceable element  54  is held at the stopped position. Where the manual operation element  38  is located at the intermediate position  38 M illustrated in  FIG. 17A  at the start of the locking operation, during the electrical locking operation, neither the locking active surface  106   a  and the locking passive surface  111   a  nor the unlocking active surface  108   a  and the unlocking passive surface  113   a  engages (come into abutment) with each other. In other words, in  FIG. 17C , the unlocking active surface  108   a  and the unlocking passive surface  113   a  are close to each other but not in abutment with each other. Therefore, during the electrical locking operation, the manual operation element  38  remains still at the intermediate position  38 M and does not rotate. 
     &lt;&lt;Unlocking Operation by Electrical Operation ( FIGS. 18A to 18C )&gt;&gt; 
       FIGS. 18A to 18C  illustrate a state in which the locking displaceable element  54  has been displaced to the unlocked position via electrical operation. The unlocking operation by electrical operation is performed by applying a direct-current voltage for the unlocking direction from the in-vehicle port locking actuator driving circuit (not illustrated) to the motor  44  for a predetermined set length of time (that is, a length of time sufficient for electrically displacing the locking displaceable element  54  from the locked position to the unlocked position). Upon the motor  44  being driven by the application of the direct-current voltage, the locking displaceable element  54  is transferred to the unlocking direction, and along with the transfer, the locking pin  36  is retracted into the housing  32 . During the transfer of the locking displaceable element  54 , the locking active surface  106   a  and the unlocking passive surface  113   a  pass each other and the unlocking active surface  108   a  and the locking passive surface  111   a  pass each other. Upon the locking displaceable element stopper abutment surface  48   b  (rear end surface of the slider  48 ) abutting against the locking displaceable element stopper  90   b  (rear end surface of the slider receiving space  90 ), the locking displaceable element  54  is mechanically stopped (state illustrated in  FIGS. 18A to 18C ). After the locking displaceable element  54  being mechanically stopped at the unlocked position, the power supply to the motor  44  is stopped because of elapse of the set length of time of the application and the locking displaceable element  54  is held at the stopped position. Where the manual operation element  38  is located at the intermediate position  38 M illustrated in  FIG. 18A  at the start of the unlocking operation, during the electrical unlocking operation, neither the locking active surface  106   a  and the locking passive surface  111   a  nor the unlocking active surface  108   a  and the unlocking passive surface  113   a  engages (come into abutment) with each other. In other words, in  FIG. 18C , the locking active surface  106   a  and the locking passive surface  111   a  are close to each other but not in abutment with each other. Therefore, during the electrical unlocking operation, the manual operation element  38  remains still at the intermediate position  38 M and does not rotate. In this way, in a locking operation and an unlocking operation by electrical operation, the manual operation element  38  does not perform a linked operation (operation of the manual operation element  38  following the locking operation or the unlocking operation) and thus the rotary shaft  50  of the manual operation element  38  is prevented from sliding on the seal packing  55  ( FIG. 4 ). Therefore, a load on the electrical driving mechanism  60  can be reduced. Also, with reference to  FIG. 18C , in a locking operation and an unlocking operation by electrical operation, the locking pin  36  can be displaced by an amount of distance that is a sum of a distance g 1  between the locking active surface  106   a  and the unlocking active surface  108   a  and a distance g 2  between the locking passive surface  111   a  and the unlocking passive surface  113   a , without making the manual operation element  38  perform a linked operation. Therefore, even if a distance between the locking passive surface  111   a  and the unlocking passive surface  113   a  (both are disposed at the slider  48 ) is set to be short in comparison with a displacement distance of the locking pin  36  necessary for displacement of the locking pin  36  between the locked position and the unlocked position, the manual operation element  38  can be prevented from performing a linked operation at the time of electrical operation. Consequently, a dimension in the front-rear direction (displacement direction) of the slider  48  can be made to be small, enabling a dimension in a front-rear direction of the actuator device  28  to be small. As a result, the actuator device  28  can be formed to be small. Note that in  FIG. 18C , an alternate long and two short dashes line  36 ′ indicates a position of the locking pin  36  after a locking operation by electrical operation. A displacement distance g 3  of displacement of the locking pin  36  between the locked position and the unlocked position by electrical operation is set to be larger than each of the distances g 1 , g 2  but be slightly smaller than a distance g 1 +g 2 . 
     &lt;&lt;Locking Operation by Manual Operation ( FIGS. 19A to 19C )&gt;&gt; 
       FIGS. 19A to 19C  illustrate a state in which the locking displaceable element  54  has been displaced to the locked position via manual operation. The locking operation by manual operation is performed by manually rotating the manual operation element  38  in the locking direction (clockwise). In other words, upon the manual operation element  38  being rotated in the locking direction, the locking active surface  106   a  engages with the locking passive surface  111   a  and presses and transfers the locking displaceable element  54  toward the locked position. Along with the transfer, the locking pin  36  projects from the housing  32 . Upon the locking displaceable element  54  reaching the locked position, the manual operation element stopper abutment surface  105   a  ( FIG. 8B ) of the manual operation element  38  abuts against the manual operation element stopper  102   a  ( FIG. 7B ) of the upper housing  32 A (state in  FIG. 15A ) before the locking displaceable element stopper abutment surface  48   a  (front end surface of the slider  48 ) abutting the locking displaceable element stopper  90   a  (front end surface of the slider receiving space  90 ). Consequently, further displacement of the manual operation element  38  is prevented. At this time, as illustrated in  FIG. 19C , the locking displaceable element stopper abutment surface  48   a  and the locking displaceable element stopper  90   a  are close to each other but are not in abutment with each other. Therefore, an excessive force is prevented from being applied between the locking active surface  106   a  and the locking passive surface  111   a , resulting in breakage of, e.g., the locking active surface forming projection  106  or the locking passive surface forming projection  111  being prevented. Note that upon locking displaceable element  54  being displaced to the unlocked position via electrical operation from the state in  FIG. 19 , the manual operation element  38  is pressed back to the intermediate position  38 M by the locking passive surface  111   a  abutting against and pressing the locking active surface  106   a . In other words, the manual operation element  38  automatically returns to the intermediate position  38 M and stops. 
     &lt;&lt;Unlocking Operation by Manual Operation ( FIGS. 20A to 20C )&gt;&gt; 
       FIGS. 20A and 20C  illustrate a state in which the locking displaceable element  54  has been displaced to the unlocked position via manual operation. The unlocking operation by manual operation is performed by manually rotating the manual operation element  38  in the unlocking direction (counterclockwise). In other words, upon the manual operation element  38  being rotated in the unlocking direction, the unlocking active surface  108   a  engages with the unlocking passive surface  113   a  and presses and transfers the locking displaceable element  54  toward the unlocked position. Along with the transfer, the locking pin  36  is retracted into the housing  32 . Upon the locking displaceable element  54  reaching the unlocked position, the manual operation element stopper abutment surface  105   b  ( FIG. 8B ) of the manual operation element  38  abuts against the manual operation element stopper  102   b  ( FIG. 7B ) of the upper housing  32 A (state in  FIG. 15B ) before the locking displaceable element stopper abutment surface  48   b  (rear end surface of the slider  48 ) abutting against the locking displaceable element stopper  90   b  (rear end surface of the slider receiving space  90 ). Consequently, further displacement of the manual operation element  38  is prevented. At this time, as illustrated in  FIG. 20C , the locking displaceable element stopper abutment surface  48   b  and the locking displaceable element stopper  90   b  are close to each other but are not in abutment with each other. Therefore, an excessive force is prevented from being applied between the unlocking active surface  108   a  and the unlocking passive surface  113   a , resulting in breakage of, e.g., the unlocking active surface forming projection  108  or the unlocking passive surface forming projection  113  being prevented. Note that upon the locking displaceable element  54  being displaced to the locked position via the electrical operation from the state in  FIG. 20 , the manual operation element  38  is pressed back to the intermediate position  38 M by the unlocking passive surface  113   a  abutting against and pressing the unlocking active surface  108   a . In other words, the manual operation element  38  automatically returns to the intermediate position  38 M and stops. 
     In the above embodiment, the round gear and the feed screw are formed as a single-piece member; however, the present invention is not limited to this example, and the round gear and the feed screw can be formed as separate components and assembled together for use. Also, the round gear and the feed screw are not limited to those of resin and can be formed of metal. In the above embodiment, the number of preceding gears disposed between the round gear and the motor is one; however, the present invention is not limited to this example, and the preceding gear can be formed of a plurality of gears. In the above embodiment, a sectional shape of the locking pin in a direction perpendicular to the axis of the locking pin is a round shape; however, the present invention is not limited to this example, and the sectional shape can be a quadrilateral or other shape. In such case, the center axis of the locking pin refers to an axis extending through the center of gravity of the sectional shape. In the above embodiment, the combination of the round gear and the preceding gear immediately preceding the round gear is formed of a combination of spur gears; however, the present invention is not limited to this example. For example, the combination of the round gear and the preceding gear immediately preceding the round gear can be formed of a worm gear using the round gear as a worm wheel and the preceding gear as a worm. In the above embodiment, a sectional shape in a direction perpendicular to the axis of the vehicle inlet is a round shape; however, the present invention is not limited to this example, and the sectional shape may be a shape other than a round shape. In such case, the center axis of the vehicle inlet refers to an axis extending through the center of gravity of the sectional shape. In the above embodiment, the locking displaceable element is formed by coupling a slider and a locking pin formed of different members; however, the configuration of the locking displaceable element is not limited to this example. In other words, a locking displaceable element can be configured by forming a slider and a locking pin as a single-piece member using a same material. The above embodiment has been described in terms of a case where the present invention is applied to an alternate-current normal charging system complying with the IEC standard “IEC 62196 TYPE 1” and the SAE standard “SAE J1772”; however, the present invention is not limited to this example, and the present invention is applicable also to an alternate-current normal charging system complying with the China national standard “GB/T 20234.2” and other normal charging systems each including a latch device. Also, the present invention is applicable not only to a normal charging system but also to a quick charging system, and furthermore, a combo-connector system in which a connector for normal charging and a connector for quick charging are combined as long as such systems include a latch device.