Patent Publication Number: US-2023139124-A1

Title: Connector

Description:
TECHNICAL FIELD 
     The present disclosure relates to a connector. 
     BACKGROUND 
     A connector disclosed in Patent Document 1 is a card edge connector and provided with a terminal fitting to be connected to a circuit board, a housing for accommodating the terminal fitting, and a board insertion groove for the insertion of the circuit board provided in the housing (hereinafter, referred to as a board accommodating portion). 
     A resilient contact piece of the terminal fitting is arranged to project into the board accommodating portion of the housing. If the circuit board is inserted into the board accommodating portion, the resilient contact piece contacts the circuit board. 
     Further, a connector disclosed in Patent Document 2 is provided with a retainer to be mounted into a housing. The retainer locks a terminal fitting accommodated into the housing. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: JP 2013-171690 A 
         Patent Document 2: JP 2013-182299 A 
       
    
     SUMMARY OF THE INVENTION 
     Problems to Be Solved 
     In Patent Document 1 and Patent Document 2, if an environmental temperature of the connector changes when a thermal expansion coefficient of the housing and that of the circuit board are largely different, there is a concern that the housing and the circuit board are deformed at different rates of expansion and shifted in position from each other. If the housing and the circuit board are largely shifted in position, there is a problem that a contact point of the resilient contact piece slides on the circuit board to increase connection resistance. 
     In contrast, if the housing is made of the same material as the circuit board, a thermal expansion difference between the housing and the circuit board can be eliminated. However, a material constituting the circuit board is often a relatively expensive and brittle material such as an LCP (Liquid Crystal Polymer) resin. Thus, if the retainer is also made of the same material as the circuit board in addition to the housing in the connector including the retainer as in Patent Document 2, it leads to a cost increase and a reduction in mechanical strength, which are not preferable. 
      Accordingly, the present disclosure aims to provide a connector with improved connection reliability of a circuit board and a terminal fitting. 
     Means to Solve the Problem 
     The present disclosure is directed to a connector with a terminal fitting to be connected to a circuit board, a housing for accommodating the terminal fitting, a board accommodating portion for accommodating the circuit board in the housing, a retainer mounting hole provided in the housing, and a retainer for locking the terminal fitting by being inserted into the retainer mounting hole, a thermal expansion difference between the retainer and the circuit board being set larger than that between the housing and the circuit board. 
     Effect of the Invention 
     According to the present disclosure, it is possible to provide a connector with improved connection reliability of a circuit board and a terminal fitting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a connector according to a first embodiment showing a state where housings are held in a second posture with respect to an outer member. 
         FIG.  2    is a perspective view showing a state where the housings are held in a first posture with respect to the outer member. 
         FIG.  3    is a side view in section showing a state where retainers are held at a full locking position with respect to the housings and the housings are held in the second posture with respect to the outer member. 
         FIG.  4    is a side view in section showing a state where the retainers are left in a half-inserted state with respect to the housings to restrict the housings from reaching the second posture with respect to the outer member. 
         FIG.  5    is a side view in section showing a state where the connector is connected to a mating connector and terminal fittings are connected to a circuit board. 
         FIG.  6    is a perspective view of the outer member. 
         FIG.  7    is a perspective view of a guide member. 
         FIG.  8    is a perspective view of a pair of upper and lower housings. 
         FIG.  9    is a view of the housing viewed from a connection surface side. 
         FIG.  10    is a perspective view of a pair of upper and lower retainers. 
         FIG.  11    is an enlarged section showing a state where the retainer is held at a partial locking position with respect to the housing. 
         FIG.  12    is an enlarged section showing a state where a locking portion of the outer member is locked to a standby lock receiving portion of the guide member. 
         FIG.  13    is an enlarged section of a connector according to a second embodiment showing a state where a terminal fitting is primarily locked by a locking lance of a retainer when the retainer is at a partial locking position. 
     
    
    
     DETAILED DESCRIPTION TO EXECUTE THE INVENTION 
     Description of Embodiments of Present Disclosure 
     First, embodiments of the present disclosure are listed and described.
     (1) The connector of the present disclosure is provided with a terminal fitting to be connected to a circuit board, a housing for accommodating the terminal fitting, a board accommodating portion for accommodating the circuit board in the housing, a retainer mounting hole provided in the housing, and a retainer for locking the terminal fitting by being inserted into the retainer mounting hole, a thermal expansion difference between the retainer and the circuit board being set larger than that between the housing and the circuit board. 
   According to the above configuration, since the thermal expansion difference between the housing and the circuit board can be made smaller or eliminated, the housing and the circuit board can be prevented from being shifted in position due to the thermal expansion difference. As a result, an increase in connection resistance between the circuit board and the terminal fitting can be prevented. On the other hand, since the retainer can be designed independently of the circuit board, a degree of freedom in designing the retainer can be enhanced, the cost of the connector can be reduced and the mechanical strength thereof can be improved.   
   (2) Preferably, the housing and the circuit board are made of the same material. According to this configuration, since the thermal expansion difference between the housing and the circuit board can be eliminated and the housing and the circuit board can be similarly deformed under a heated environment, an increase in connection resistance between the circuit board and the terminal fitting can be more reliably prevented.   (3) The retainer may be made of a material tougher than the housing. According to this configuration, there is less concern for breakage when the retainer locks the terminal fitting and a locked state of the retainer and the terminal fitting can be satisfactorily maintained.   (4) The housing may include a cavity, the terminal fitting being inserted into the cavity, the retainer may be held movably to a partial locking position and a full locking position with respect to the housing, shallowly inserted into the retainer mounting hole at the partial locking position and inserted deeper into the retainer mounting hole at the full locking position than at the partial locking position, and the retainer may include a deflectable and deformable locking lance for primarily locking the terminal fitting located in the cavity by projecting into the cavity at the partial locking position and a retaining portion for secondarily locking the terminal fitting at the full locking position.   

     If the housing is made of the same LCP (liquid crystal polymer) resin as the circuit board, it is difficult to provide the housing with a locking lance for primarily locking the terminal fitting due to the brittleness of the LCP resin. In that respect, according to the above configuration, the locking lance of the retainer can primarily lock the terminal fitting when the retainer is at the partial locking position. Here, since the retainer is made of the material tougher than the housing, the locking lance can be formed with good moldability. 
     Details of Embodiments of Present Disclosure 
     Specific examples of the present disclosure are described below with reference to the drawings. Note that the present invention is not limited to this illustration and is intended to be represented by claims and include all changes in the scope of claims and in the meaning and scope of equivalents. 
     First Embodiment 
     A connector  10  according to a first embodiment includes housings  20 , an outer member  21 , terminal fittings  60  and retainers  80 . The outer member  21  is connectable to a mating connector  100 . Note that, in the following description, surface sides facing each other when the connection of the connector  10  and the mating connector  100  (hereinafter, referred to as the both connectors  10 ,  100 ) is started are referred to as front sides concerning a front-rear direction. 
     Mating Connector 
     As shown in  FIG.  5   , the mating connector  100  includes a receptacle  110  and a circuit board  120 . The circuit board  120  is made of LCP (Liquid Crystal Polymer) resin or the like as a base material except electrically conductive portions  121 . Glass fiber and other additives may be added to the LCP resin as the base material in the material constituting the circuit board  120 . 
     The receptacle  110  is made of synthetic resin. A hole-like lock receiver  111  is provided to penetrate through a front end side of an upper wall part of the receptacle  110 . The receptacle  110  and the circuit board  120  are mounted on an unillustrated case. The receptacle  110  and the circuit board  120  are kept at fixed relative positions via the case. The circuit board  120  is arranged in the receptacle  110 . 
     The electrically conductive portion  121  includes a connecting member  122  formed by bending a metal plate material. The connecting member  122  is fit to a projection part projecting on a plate surface (surface) of the circuit board  120  and formed by molding. The connecting member  122  is connected to an unillustrated conductive path of the circuit board  120 . A plurality of the connecting members  122  are arranged to stand side by side in a lateral direction on the plate surface of the circuit board  120 . 
     Schematic Configuration of Overall Connector 
     As shown in  FIGS.  1  and  2   , the housings  20  are arranged inside the outer member  21 . A pair of the housings  20  are provided in a vertical direction (vertical direction of  FIG.  1   ). The housing  20  is assembled displaceably to a first posture (state shown in  FIG.  2   ) and a second posture (first state) with respect to the outer member  21 . The first posture is a posture in which the housing  20  is horizontally arranged along the front-rear direction. The second posture is a posture in which the housing  20  is obliquely arranged in a direction intersecting the front-rear direction. A guide member  22  for ensuring the stability of displacements of the housings  20  is provided between the outer member  21  and the housings  20 . 
     The retainer  80  is mounted into the housing  20 . A pair of the retainers  80  are provided in the vertical direction to correspond to the housings  20 . A plurality of the terminal fittings  60  are accommodated in the housing  20 . The retainer  80  locks the terminal fittings  60  and restricts the terminal fittings  60  from coming out from the housing  20 . 
     As shown in  FIG.  5   , the terminal fittings  60  are electrically connected to the electrically conductive portions  121  of the circuit board  120 . When the housing  20  is displaced from the second posture to the first posture, the terminal fittings  60  are displaced from positions facing the plate surface of the circuit board  120  toward the conductive portions  121 . 
     Outer Member 
     The outer member  21  is made of synthetic resin and has a box shape open forward and rearward as a whole as shown in  FIG.  6   . The outer member  21  is made of the same material (material containing an LCP resin as a base material as described later) as the housings  20 . However, in view of cost and the like, the outer member  21  can also be made of the same material (material containing a PBT (Polybutylene Terephthalate) resin as a base material) as the retainer  80  or a material different from those of the retainer  80  and the housings  20 . 
     This outer member  21  includes a pair of side walls  23  laterally facing each other, an upper wall  24  extending between the upper ends of the both side walls  23  and a lower wall  25  extending between the lower ends of the both side walls  23 . A housing accommodation space  26  is provided inside the outer member  21 . 
     Each of the both side walls  23  is provided with a pair of upper and lower guide grooves  27  for guiding displacements of the housings  20 . The guide groove  27  penetrates through the corresponding side wall  23  in a wall thickness direction and communicates with the housing accommodation space  26  on an inner side. The guide grooves  27  include straight regions arranged along the front-rear direction in a rear part, separating regions inclined to be vertically separated toward the front from the straight regions, short top regions arranged to extend forward along the front-rear direction from the separating regions and proximate regions inclined to approach a vertically central part of the side wall  23  toward the front from the top regions. The straight regions are open in the rear end of the outer member  21 . 
     A pair of upper and lower insertion grooves  28  are provided in both upper and lower end parts of the inner surface of each of the both side walls  23 . The insertion groove  28  is a bottomed groove closed on the outer surface of the side wall  23 , extends in the front-rear direction and is open in the front end of the side wall  23 . Resilient locking portions  29  are provided in both upper and lower end parts of the both side walls  23  by cutting the bottom surfaces of the insertion grooves  28 . The resilient locking portion  29  is deflectable and deformable inward and outward (leftward and rightward) with a rear end part as a fulcrum. As shown in  FIG.  12   , a locking projection  31  projecting inward is provided on a front end part (tip part) of the resilient locking portion  29 . A later-described inserting portion  41  of the guide member  22  is inserted into the insertion groove  28 . The resilient locking portion  29  locks later-described lock receiving portions  42 ,  43  and  44  of the guide member  22 . 
     As shown in  FIG.  6   , the upper wall  24  and the lower wall  25  are provided in a rear part of the outer member  21 . The upper and lower surfaces of the outer member  21  have openings  32  in front of the upper and lower walls  24 ,  25 . The openings  32  communicate with the housing accommodation space  26  on inner sides. Both left and right ends of the openings  32  are defined by the both side walls  23 . The openings  32  are open forward. Rear parts of the openings  32  are defined by the front ends of the upper and lower walls  24 ,  25 . The front ends of the upper and lower walls  24 ,  25  are edge parts linearly arranged along a width direction (lateral direction) and constituted as interfering portions  33  capable of interfering with the retainers  80  in a half-inserted state to be described later. The housing  20  in an inclined posture to be described later is allowed to enter and escape into the opening  32 . The upper wall  24  is provided with a deflectable and deformable lock arm  34 . The front end of the lock arm  34  serving as a deflection fulcrum constitutes a laterally central part of the interfering portion  33 . 
     Guide Member 
     The guide member  22  is made of synthetic resin and has a box shape open forward and rearward as a whole as shown in  FIG.  7   . The guide member  22  is arranged inside the outer member  21  and outside the housings  20 . The guide member  22  is displaceable in synchronism with the housings  20  with respect to the outer member  21 . 
     The upper and lower surfaces of the guide member  22  have window portions  35 , which are rectangular openings in a plan view and a bottom view. The peripheries of the window portions  35  are defined by rectangular frame parts in the upper and lower surfaces of the guide member  22 . The periphery of the front surface of the guide member  22  is also defined by a rectangular frame part including left and right side wall parts. The window portions  35  communicate with the openings  32  with the guide member  22  arranged inside the outer member  21 . The housings  20  in the inclined posture are allowed to enter and escape into the window portions  35 . 
     The guide member  22  includes a partition wall  36  extending between vertically central parts of the left and right side wall parts. As shown in  FIG.  3   , the partition wall  36  is in the form of a horizontal plate along the front-rear direction. With the guide member  22  arranged inside the outer member  21 , the housing accommodation space  26  is divided into upper and lower parts by the partition wall  36 . The tip (front end) of the partition wall  36  is linearly arranged along the width direction behind the front ends of the side wall parts. 
     A pair of upper and lower guiding grooves  37  for receiving later-described guide pins  71  of the housings  20  are provided in each of the left and right side wall parts of the guide member  22 . The guiding grooves  37  have straight regions extending in the front-rear direction and open in the rear end of the side wall part and separating regions extending in directions away from each other from the front ends of the straight regions. Front and rear guide pins  71  are inserted into both end sides of the straight region of the guiding groove  37 . The front guide pins  71  are displaceably arranged in the separating regions of the guiding grooves  37  when the housing  20  is in the inclined posture with respect to the outer member  21 . 
     The left and right side wall parts of the guide member  22  are provided with resilient arm portions  38  defining straight parts of the guiding grooves  37 . A claw-like holding projection  39  projecting inward in a rear part of the guiding groove  37  is provided on a rear end part of the resilient arm portion  38 . The resilient arm portion  38  is deflectable and deformable with a front end part as a fulcrum. 
     A pair of upper and lower inserting portions  41  continuous with the upper and lower surfaces and protruding laterally are provided on each of the left and right side wall parts of the guide member  22 . The inserting portion  41  is in the form of a rib extending in the front-rear direction. The inserting portion  41  is provided with the standby lock receiving portion  42 , the assembling lock receiving portion  43  and the restricting lock receiving portion  44 . These lock receiving portions  42 ,  43  and  44  are provided at intervals in the front-rear direction by recessing the side surface (lateral end surface) of the inserting portion  41 . Specifically, the standby lock receiving portion  42 , the assembling lock receiving portion  43  and the restricting lock receiving portion  44  are successively provided side by side from front in the side surface of the inserting portion  41 . 
     The guide member  22  can be assembled with the outer member  21  from front and reach an assembled position by way of a movement restricting position. Further, the guide member  22  can be moved relatively forward with respect to the outer member  21  and reach a standby position. The restricting lock receiving portion  44 , the assembling lock receiving portion  43  and the standby lock receiving portion  42  receive the locking projection  31  of the resilient locking portion  29  respectively at the movement restricting position, the assembled position and the standby position. 
     Terminal Fittings 
     The terminal fitting  60  is integrally formed, such as by bending an electrically conductive metal plate. As shown in  FIG.  3   , the terminal fitting  60  includes a base portion  61  extending in the front-rear direction, a box-shaped terminal body  62  provided in a front part of the base portion  61  and a barrel portion  63  in the form of an open barrel provided in a rear part of the base portion  61 . The barrel portion  63  is crimped and connected to an end part of a wire  90 . A deflectable and deformable resilient contact piece  64  is arranged in the terminal body  62 . The resilient contact piece  64  is folded after rising from the front end of the base portion  61 , and shaped to be long in the vertical direction as a whole. The terminal body  62  is also shaped to be long in the vertical direction to correspond to the resilient contact piece  64 . A retained portion  65  along the vertical direction is provided on the rear end edge of the terminal body  62 . The retained portion  65  is formed to be long in the vertical direction due to a height difference between the terminal body  62  and the barrel portion  63 . The retained portion  65  is locked by a later-described retaining portion  85  of the retainer  80 . The base portion  61  of the terminal fitting  60  is provided with a hole open to allow the entrance of the connecting member  122  of the circuit board  120 . The resilient contact piece  64  includes a contact point portion  66  at a position facing the hole of the base portion  61 . 
     Housings 
     The housing  20  is made of synthetic resin and, as shown in  FIG.  8   , has a flat shape extending in the width direction as a whole. The material of the housings  20  is the same as that of the circuit board  120  and contains the LCP resin as the base material. However, the housings  20  may be made of a material different from that of the circuit board  120  and may be preferably made of a material having a thermal expansion coefficient (linear expansion coefficient) approximate to that of the material constituting the circuit board  120 . Glass fiber and other additives may be added to the LCP resin as the base material in the material constituting the housings  20 . 
     As shown in  FIG.  3   , the housing  20  is provided with a plurality of cavities  45  (only one is shown in  FIG.  3   ). The respective cavities  45  are arranged in a row in the width direction. The cavity  45  has a vertically long rectangular cross-sectional shape, extends in the front-rear direction and is open in the rear end of the housing  20 . The terminal fitting  60  is inserted into each cavity  45  from behind. 
     As shown in  FIG.  8   , inspection windows  47  for a continuity inspection of the terminal fitting  60  are provided in the front wall  46  of the housing  20  for each cavity  45 . The front surface of each cavity  45  is closed by the front wall  46  of the housing  20  except at the inspection window  47 . 
     As shown in  FIG.  4   , the housing  20  includes a connection port  48  in an inner wall  52  facing the base portions  61  of the terminal fittings  60  inserted into the respective cavities  45 . As shown in  FIG.  9   , the connection port  48  is a slit-like hole long in the width direction, penetrates through the inner wall  52  and communicates with the respective cavities  45 . The connecting members  122  of the circuit board  120  are inserted into the connection port  48 . The connecting member  122  enters the terminal body  62  through the hole of the base portion  61  from the connection port  48  and contacts the contact point portion  66  of the resilient contact piece  64  in the terminal body  62 . As shown in  FIG.  3   , the inner wall  52  of the housing  20  includes a locking hole  49  behind the connection port  48 . A projection  67  provided in the base portion  61  by cutting and raising enters the locking hole  49 . As shown in  FIG.  4   , the outer surface of the inner wall  52  on a side opposite to the cavities  45  is constituted as a flat connection surface  51  in which the connection port  48  is open. 
     The housing  20  includes a retainer mounting hole  54  in an outer wall  53  located on a side opposite to the inner wall  52  via the respective cavities  45 . The retainer mounting hole  54  is a rectangular hole long in the width direction, penetrates through the outer wall  53  and communicates with the respective cavities  45 . The retainer  80  is inserted into the retainer mounting hole  54 . As shown in  FIG.  3   , a rear part of the retainer mounting hole  54  has a stepped support surface  55  capable of supporting a rear part  86  of the retainer  80  at a midway position in a thickness direction of the outer wall  53 . 
     As shown in  FIG.  8   , a pair of retainer locking holes  56  are provided in both left and right end parts of the retainer mounting hole  54 . The retainer locking hole  56  has a slit-like region extending forward. As shown in  FIG.  11   , the housing  20  is provided with claw-like full locking portions  57  projecting on the front ends of the retainer locking holes  56  and a claw-like partial locking portion  58  on the rear end of the retainer mounting hole  54 . The partial locking portion  58  is larger than the full locking portions  57  and located more outward (upper side of  FIG.  11   ) than the full locking portions  57 . Further, the housing  20  is provided with a guide rib  59  extending in the vertical direction at a midway position in the front-rear direction of the retainer mounting hole  54 . The outer surface of the outer wall  53  on a side opposite to the cavities  45  is constituted as one flat surface  73 . As shown in  FIG.  3   , the one surface  73  of the outer wall  53  is arranged to proximately face the interfering portion  33  of the outer member  21  when the housing  20  is in the second posture to be described later. 
     As shown in  FIG.  9   , a pair of front and rear guide pins  71  are provided on each of both left and right surfaces of the housing  20 . The respective guide pins  71  have a cylindrical shape and project at an interval in the front-rear direction on both left and right surfaces of the housing  20 . A flange portion  72  protruding over an entire circumference is provided on a tip part of each guide pin  71 . 
     Retainers 
     The retainer  80  is made of synthetic resin and includes, as shown in  FIG.  10   , a body portion  81  extending long in the width direction and locking portions  82 ,  83  and  84  connected to both left and right ends of the body portion  81 . The material constituting the retainers  80  is a material different from that constituting the housings  20  and the circuit board  120  and having a thermal expansion coefficient distant from the thermal expansion coefficient (linear expansion coefficient) of the material constituting the circuit board  120 . A difference in thermal expansion coefficient between the materials of the retainers  80  and the circuit board  120  is set larger than that between the materials of the housings  20  and the circuit board  120 . In the case of the first embodiment, the material constituting the retainers  80  contains the PBT resin as the base material. Glass fiber and other additives may be added to the PBP resin as the base material in the material constituting the retainers  80 . 
     The retainer  80  is sized to be fit into the retainer mounting hole  54 . The retainer  80  is held movably with respect to the housing  20  to a partial locking position (see  FIG.  4   ) where the retainer  80  is shallowly inserted in the retainer mounting hole  54  and a full locking position (see  FIGS.  3  and  5   ) where the retainer  80  is inserted deeper into the retainer mounting hole  54  than in a state at the partial locking position. 
     The front surface of the body portion  81  is a vertical surface along the vertical direction and width direction and constituted as the retaining portion  85 . As shown in  FIG.  5   , the retaining portion  85  faces the retained portions  65  of the terminal fittings  60  inserted into the respective cavities  45  and collectively locks the respective terminal fittings  60  at the full locking position. 
     As shown in  FIG.  10   , the rear part  86  of the body portion  81  is arranged to be slightly lower than a front part  87  via a step. The rear part  86  of the body portion  81  is supported on the support surface  55  of the retainer mounting hole  54  at the full locking position. A plurality of ribs  88  extending in the front-rear direction are provided side by side at positions corresponding to separation wall parts partitioning between adjacent ones of the respective cavities  45  in the housing  20  on the inner surface (surface facing the terminal fittings  60  with the retainer  80  mounted in the housing  20 ) of the front part  87  of the body portion  81 . The outer surface (surface facing outward of the housing  20  with the retainer  80  mounted in the housing  20 ) of the body portion  81  is a flat horizontal surface extending in the front-rear direction and lateral direction. 
     As shown in  FIG.  11   , the locking portion  82 ,  83  and  84  is inserted into the retainer locking hole  56 . The locking portion  82 ,  83  and  84  includes a full locking arm  82 , a guide piece  83  and a partial locking arm  84  arranged side by side in the front-rear direction. 
     As shown in  FIG.  10   , the guide pieces  83  are in the form of strips connected to left and right end parts of the front part  87  and projecting further inward (toward a side where the terminal fittings  60  are located with the retainer  80  mounted in the housing  20 ) than the body portion  81 . The full locking arm  82  is in the form of an arm projecting inward from a base end part connected to a front side of the guide piece  83 . The full locking arm  82  is deflectable and deformable in the front-rear direction with the base end part as a fulcrum. A claw-like part projecting forward is provided on a tip part of the full locking arm  82 . The partial locking arms  84  are in the form of arms connected to left and right end parts of the rear part  86  and projecting further inward than the body portion  81 . The partial locking arm  84  is deflectable and deformable in the front-rear direction with a base end part connected to the body portion  81  as a fulcrum. A claw-like part projecting rearward is provided on a tip part of the partial locking arm  84 . The partial locking arm  84  is configured to have a larger width in the front-rear direction than the full locking arm  82 . 
     Assembling Method, Connection Method and Connection Structure of Connector 
     First, the pair of upper and lower housings  20  are inserted into the housing accommodation space  26  of the outer member  21  from behind. At this time, the respective front and rear guide pins  71  are inserted into the corresponding guide grooves  27 . The front guide pins  71  are arranged in the proximate regions of the guide grooves  27  by way of the separating regions and the top regions from the straight regions. The rear guide pins  71  are arranged in the straight regions of the guide grooves  27 . When the front guide pins  71  ride over the top regions of the guide grooves  27 , the housings  20  are displaced from the second posture, which is the inclined posture, to the first posture, which is the horizontal posture. The front guide pins  71  stay on slopes of the proximate regions of the guide grooves  27 , thereby restricting the housings  20  from coming out rearward. 
     Subsequently, the guide member  22  is inserted into the outer member  21  from front. The inserting portions  41  slide on the groove surfaces of the insertion grooves  28 , whereby an inserting operation of the guide member  22  is guided. Further, the guide pins  71  are inserted into the guiding grooves  37 . The locking projections  31  slide on the inserting portions  41 , whereby the resilient locking portions  29  are deflected and deformed. When the guide member  22  reaches the movement restricting position in the process of inserting the guide member  22 , the locking projections  31  are fit into the restricting lock receiving portions  44  and the resilient locking portions  29  resiliently return. As the resilient locking portions  29  resiliently return, the rear guide pins  71  interfere with the holding projections  39  and the resilient arm portions  38  are deflected and deformed. When the guide member  22  reaches the assembled position, the resilient arm portions  38  resiliently return and the holding projections  39  move to behind the rear guide pins  71 . At this time, the front guide pins  71  are located in contact with the front ends of the guiding grooves  37 . Thus, the guide member  22  is assembled at the assembled position with movements in the front-rear direction with respect to the housings  20  restricted. When the guide member  22  reaches the assembled position, the locking projections  31  of the resilient locking portions  29  are fit into the assembling lock receiving portions  43  and the guide member  22  is held at the assembled position with respect to the outer member  21 . 
     When the guide member  22  is at the assembled position, the pair of upper and lower housings  20  are in the horizontal first posture to form a board accommodating portion  50  between the connection surfaces  51  thereof (see  FIG.  2   ). The board accommodating portion  50  has a vertical opening dimension equivalent to a plate thickness of the circuit board  120  in the first posture. Subsequently, the retainers  80  are inserted into the retainer mounting holes  54  through the openings  32  and the window portions  35  from above and below the outer member  21 . 
     When the retainer  80  reaches the full locking position, the claw-like parts of the partial locking arms  84  are arranged in contact with the partial locking portion  58  from inside to restrict the retainer  80  from coming out from the retainer mounting hole  54  as shown in  FIG.  11   . Further, when the retainer  80  reaches the partial locking position, the claw-like parts of the full locking arms  82  are arranged in contact with the full locking portions  57  from outside to restrict a movement of the retainer  80  to the full locking position. A moving operation of the retainer  80  is guided by the guide rib  59  arranged along the guide pieces  83 . 
     With the retainer  80  located at the partial locking position, the body portion  81  is retracted from the respective cavities  45  without entering the respective cavities  45  except the respective ribs  88 . Specifically, an outer part of the body portion  81  is located to project outward from the one surface  73  of the outer wall  53 . Particularly, the rear part  86  of the body portion  81  is separated from the support surface  55  and entirely arranged outside the one surface  73  of the outer wall  53  (see  FIG.  4   ). 
     As described above, when the housings  20  are in the first posture and the retainers  80  are at the partial locking position, the terminal fitting  60  is inserted into each cavity  45  from behind. Here, the terminal fitting  60  is smoothly inserted into the cavity  45  without receiving any insertion resistance from a locking lance since the locking lance does not project into the cavity  45 . When the terminal fitting  60  is properly inserted into the cavity  45 , a front wall part of the terminal body  62  abuts on the front wall  46  of the housing  20 , whereby the inserting operation of the terminal fitting  60  is restricted. Further, the projection  67  enters the locking hole  49  and is hooked to the rear end of the locking hole  49 , whereby the terminal fitting  60  is restricted from coming out from the cavity  45 . With the terminal fitting  60  properly inserted in the cavity  45 , the contact point portion  66  of the resilient contact piece  64  is arranged to face the hole of the base portion  61  and the connection port  48  of the housing  20  from outside. 
      In the above state, the retainer  80  is pushed to the full locking position with respect to the housing  20 . When the retainer  80  reaches the full locking position, the claw-like parts of the full locking arms  82  are arranged in contact with the full locking portions  57  from inside to restrict a return movement of the retainer  80  to the partial locking position. Further, when the retainer  80  reaches the full locking position, the rear part  86  of the body portion  81  abuts on the support surface  55  to restrict an inward movement of the retainer  80 . 
     With the retainer  80  located at the full locking position, the retaining portion  85  is arranged in contact with the retained portion  65  of the terminal body  62  along the vertical direction. In this way, the terminal fitting  60  is reliably restricted from coming out from the cavity  45 . 
     Further, with the retainer  80  located at the full locking position, the entire retainer  80  is inserted in the retainer mounting hole  54 . At this time, the outer surface of the body portion  81  is arranged to be continuous and flush with the one surface  73  of the housing  20  or retracted inwardly from the one surface  73  of the housing  20 . 
     Subsequently, the housing  20  is displaced from the first posture to the second posture. For example, the housing  20  can be displaced to the second posture by pressing the flange portions  72  of the rear guide pins  71  rearward. If a pressing force to the second posture is applied to the housing  20 , the locking projections  31  of the guide member  22  come out from the assembling lock receiving portions  43  and the resilient locking portions  29  are deflected and deformed since the housing  20  and the guide member  22  are integrated. As the housing  20  reaches the second posture, the resilient locking portions  29  resiliently return and the locking projections  31  are fit into the standby lock receiving portions  42  (see  FIG.  12   ). In this way, the guide member  22  is held at the standby position in the outer member  21 . Simultaneously, the housing  20  is held in the second posture in the outer member  21  via the guide member  22 . 
     When the guide member  22  is at the standby position, the front guide pins  71  are located in the top regions of the guide grooves  27  and the rear guide pins  71  are located in rear end parts of the straight regions of the guide grooves  27 . 
     The pair of upper and lower housings  20  are arranged to be mutually open forward in the second posture. At this time, the board accommodating portion  50  formed between the connection surfaces  51  of the respective housings  20  expands the vertical opening dimension toward the front (see  FIG.  3   ). The housing  20  does not project outward from the opening  32  and is maintained in a state arranged inside the outer member  21  also in the second posture. The connection surface  51  of the housing  20  is arranged to face an inner front side in the second posture. The one surface  73  of the housing  20  is arranged closer to the interfering portion  33  in the second posture than in the first posture. The connector  10  is shipped to a site, where a connecting operation to the mating connector  100  is performed, with the housings  20  held in the second posture. 
     Here, if the retainer  80  is at a midway position between the partial locking position and the full locking position or left at the partial locking position without reaching the full locking position (these cases are referred to as a half-inserted state), the outer part of the body portion  81  projects outward from the one surface  73  of the housing  20 . Thus, the one surface  73  of the housing  20  approaches the interfering portion  33 , whereby the outer part of the body portion  81  interferes with the interfering portion  33  to restrict the housing  20  from reaching the second posture (see  FIG.  4   ), in the process of displacing the housing  20  to the second posture. In this case, since the guide member  22  also does not reach the standby position and the resilient locking portions  29  and the standby lock receiving portions  42  are not locked, the inclined posture of the housing  20  cannot be maintained with the outer part of the body portion  81  interfering with the interfering portion  33 . Accordingly, the front guide pins  71  are displaced along the inclination of the proximate regions of the guide grooves  27  and the housing  20  tries to return to the first posture, which is the horizontal posture. As a result, it can be reliably known that the housing  20  has not reached the second posture yet, and it can be detected that the retainer  80  is in the half-inserted state before the shipment to the site where the both connectors  10 ,  100  are connected. 
     As described above, in connecting the both connectors  10 ,  100 , it is ensured that the housings  20  are held in the second posture with respect to the outer member  21  and the retainers  80  are at the full locking position. 
     If the connector  10  is shallowly fit into the receptacle  110  when the connection of the both connectors  10 ,  100  is started, the circuit board  120  is inserted into the board accommodating portion  50 . Then, an end surface of the circuit board  120  abuts on the tip of the partition wall  36  of the guide member  22  to apply a rearward pushing force to the guide member  22 . Then, the locking projections  31  come out from the standby lock receiving portions  42  and the resilient locking portions  29  are deflected and deformed. 
     When the connecting operation of the both connectors  10 ,  100  proceeds, the circuit board  120  pushes the guide member  22  and the guide member  22  moves rearward together with the housings  20  with respect to the outer member  21 . During this time, the front guide pins  71  are displaced forward along the proximate regions of the guide grooves  27  to gradually reduce angles of inclination of the housings  20 . Further, the locking projections  31  are displaced further forward than the inserting portions  41  and the resilient locking portions  29  resiliently return. 
     When the both connectors  10 ,  100  are properly connected, the housings  20  are in the first posture, which is the horizontal posture, and the front and rear guide pins  71  move to the straight regions of the guide grooves  27 . In the process of reaching the first posture from the second posture, the housings  20  gradually approach the plate surfaces of the circuit board  120  and the connecting members  122  of the circuit board  120  enter the terminal bodies  62  through the holes of the base portions  61  and the connection ports  48  of the housings  20 . 
     When the housing  20  reaches the first posture, the connecting members  122  contact the contact point portions  66  while deflecting the resilient contact pieces  64 . In this way, the terminal fittings  60  are connected to the electrically conductive portions  121  of the circuit board  120 . Since the resilient contact pieces  64  do not contact corner parts of the end surface of the circuit board  120 , the resilient contact pieces  64  are not damaged due to interference with the corner parts of the end surface of the circuit board  120 . Thus, a connected state of the terminal fittings  60  and the circuit board  120  can be satisfactorily realized. Further, when the terminal fittings  60  and the circuit board  120  are connected, the projection-like part of the lock arm  34  is fit into the lock receiver  111  of the receptacle  110  and the both connectors  10 ,  100  are held in the connected state. 
     With the both connectors  10 ,  110  properly connected, the circuit board  120  is tightly arranged in the board accommodating portion  50  between the connection surfaces  51  of the pair of upper and lower housings  20 . Here, the housings  20  and the circuit board  120  are made of the same material and there is no difference in linear expansion coefficient. This can prevent relative positions of the housings  20  and the circuit board  120  from being shifted. If the housings  20  and the circuit board  120  should be made of different materials, the relative positions of the housings  20  and the circuit board  120  are not largely shifted if a difference in thermal expansion coefficient between the housings  20  and the circuit board  120  is smaller than a difference in thermal expansion coefficient between retainers  80  and the circuit board  120 . Thus, the terminal fittings  60  mounted into the housings  20  can also be maintained at fixed relative positions to the circuit board  120  and a situation can be prevented in which the contact point portions  66  of the terminal fittings  60  slide on the connecting members  122  to increase connection resistance. On the other hand, the retainers  80  are made of PTB resin or the like unlike the housings  20 . Thus, the retainers  80  are excellent in toughness and a state where the retaining portion  85  locks the retained portions  65  of the terminal bodies  62  can be satisfactorily maintained. 
     As described above, according to the first embodiment, the housings  20  and the circuit board  120  can be prevented from being shifted in position due to a thermal expansion difference since the difference in thermal expansion coefficient between the housings  20  and the circuit board  120  is smaller than the difference in thermal expansion coefficient between retainers  80  and the circuit board  120 . As a result, an increase of the connection resistance between the circuit board  120  and the terminal fittings  60  can be prevented. On the other hand, since the material of the retainers  80  is not limited to that of the circuit board  120 , a degree of freedom in designing the retainers  80  can be enhanced. As a result, the cost of the entire connector  10  can be reduced and the mechanical strength thereof can be improved. 
     Particularly, since the retainers  80  are made of the material containing the PBT resin tougher than the housings  20  as the base material, a concern for breakage when the terminal fittings  60  are locked can be reduced. 
     Further, according to the first embodiment, the one surface  73  of the housing  20  can approach the interfering portion  33  and the retainer  80  in the half-inserted state can interfere with the interfering portion  33  in the process of displacing the housing  20  from the first posture to the second posture. Thus, the housing  20  is restricted from reaching the second posture and it can be detected that the retainer  80  is in the half-inserted state. Therefore, whether or not the retainers  80  are properly inserted can be detected before the shipment to the site where the both connectors  10 ,  100  are connected. 
     Further, since an operation of detecting the half-inserted state of the retainer  80  is linked to an operation of connecting the terminal fittings  60  to the surface of the circuit board  120  in the case of the first embodiment, it is not necessary to individually perform each operation and a workload can be reduced. 
     Moreover, since the retainer  80  in the half-inserted state can interfere with the interfering portion  33  in the process of displacing the housing  20  from the first posture, which is the horizontal posture, to the second posture, which is the inclined posture, the interfering portion  33  needs not be shaped to project toward the housing  20  and can have a simple shape. 
     Second Embodiment 
       FIG.  13    shows a second embodiment. The second embodiment differs from the first embodiment in the shape of a retainer  80 . The other configuration is similar to that of the first embodiment. Note that, in the following description, the same or corresponding structures as or to those of the first embodiment are denoted by the same reference signs as in the first embodiment and repeated description is omitted. 
     The retainer  80  includes a plurality of locking lances  89  on the inner surface (surface facing terminal fittings  60  with the retainer  80  mounted in a housing  20 ) of a front part  87  of a body portion  81 . The respective locking lances  89  are arranged side by side in a width direction at positions corresponding to cavities  45  on the inner surface of the front part  87  of the body portion  81 . The locking lance  89  includes a base end part in a rear end part of the inner surface of the front part  87  of the body portion  81  and is cantilevered forward from the base end part. The locking lance  89  is deflectable and deformable with the base end part as a fulcrum. 
     As shown in  FIG.  13   , when the retainer  80  is at a partial locking position with respect to the housing  20 , tip parts (front end parts) of the locking lances  89  are arranged to enter the cavities  45 . In the process of inserting the terminal fitting  60  into the cavity  45 , a terminal body  62  interferes with the tip part of the locking lance  89  to deflect and deform the locking lance  89 . When the terminal body  62  abuts on a front wall  46  of the housing  20  and the terminal fitting  60  is properly inserted into the cavity  45 , the locking lance  89  resiliently returns and the tip part of the locking lance  89  is arranged to face a retained portion  65  of the terminal body  62 . In this way, the terminal fitting  60  is primarily locked by the locking lance  89  of the retainer  80 . Thereafter, when the retainer  80  is pushed to a full locking position with respect to the housing  20 , a retaining portion  85  of the body portion  81  is arranged to face the retained portions  65  of the terminal bodies  62  together with the locking lances  89 . In this way, the terminal fittings  60  are secondarily locked by the retaining portion  85  and reliably retained and held in the cavities  45 . 
     Here, the housing  20  is made of a material containing an LCP resin, which is the same material as a circuit board  120 , as a base material to eliminate a thermal expansion difference between the housing  20  and the circuit board  120 . However, since the housing  20  made of the material containing the LCP resin as the base material tends to be relatively brittle, it is difficult to form the deflectable and deformable locking lances  89 . 
     On the other hand, in the case of the second embodiment, the locking lances  89  are formed on the retainer  80  made of the material containing the PBT resin, which is tough instead of brittle, as the base material. Thus, the locking lances  89  can be formed on the retainer  80  without any problem. Further, a resilient locking function of the locking lances  89  can be satisfactorily exhibited. 
     Other Embodiments of Present Disclosure 
     The embodiments disclosed this time should be considered illustrative in all aspects, rather than restrictive. 
     Although the housing is arranged relatively displaceably inside the outer member in the case of the above embodiments (first and second embodiments), the connector may not include the outer member and the housing may be singly inserted into the receptacle of the mating connector as another embodiment. 
     Although the connector includes the pair of upper and lower housings and the board accommodating portion is provided between the pair of upper and lower housings in the case of the above embodiments, the connector may include one housing and the board accommodating portion may be provided inside the housing as another embodiment. 
     Although the circuit board and the housings are made of the material containing the LCP resin as the base material and the retainers are made of the material containing the PBT resin as the base material in the case of the above embodiments, it is sufficient that the thermal expansion difference between the retainers and the circuit board is larger than that between the housings and the circuit board and the types of the resins constituting the retainers, the housings and the circuit board are not particularly limited as another embodiment. 
     LIST OF REFERENCE NUMERALS 
     
         
           10  ... connector 
           20  ... housing 
           21  ... outer member 
           22  ... guide member 
           23  ... side wall 
           24  ... upper wall 
           25  ... lower wall 
           26  ... housing accommodation space 
           27  ... guide groove 
           28  ... insertion groove 
           29  ... resilient locking portion 
           31  ... locking projection 
           32  ... opening 
           33  ... interfering portion 
           34  ... lock arm 
           35  ... window portion 
           36  ... partition wall 
           37  ... guiding groove 
           38  ... resilient arm portion 
           39  ... holding projection 
           41  ... inserting portion 
           42  ... standby lock receiving portion 
           43  ... assembling lock receiving portion 
           44  ... restricting lock receiving portion 
           45  ... cavity 
           46  ... front wall 
           47  ... inspection window 
           48  ... connection port 
           49  ... locking hole 
           50  ... board accommodating portion 
           51  ... connection surface 
           52  ... inner wall 
           53  ... outer wall 
           54  ... retainer mounting hole 
           55  ... support surface 
           56  ... retainer locking hole 
           57  ... full locking portion 
           58  ... partial locking portion 
           59  ... guide rib 
           60  ... terminal fitting 
           61  ... base portion 
           62  ... terminal body 
           63  ... barrel portion 
           64  ... resilient contact piece 
           65  ... retained portion 
           66  ... contact point portion 
           67  ... projection 
           71  ... guide pin 
           72  ... flange portion 
           73  ... one surface 
           80  ... retainer 
           81  ... body portion 
           82  ... full locking arm (locking portion) 
           83  ... guide piece (locking portion) 
           84  ... partial locking arm (locking portion) 
           85  ... retaining portion 
           86  ... rear part 
           87  ... front part 
           88  ... rib 
           89  ... locking lance 
           90  ... wire 
           100  ... mating connector 
           110  ... receptacle 
           111  ... lock receiver 
           120  ... circuit board 
           121  ... electrically conductive portion 
           122  ... connecting member