Patent Publication Number: US-9893441-B2

Title: Card edge connector and method for manufacturing same

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a card edge connector and a method for manufacturing the same. 
     2. Description of the Related Art 
     Japanese Unexamined Patent Publication No. 2008-091047 discloses a card edge connector with a housing including a board accommodation space and a plurality of terminal fittings accommodated in the housing and arranged to face each other across the board accommodation space. This card edge connector comes into contact with a circuit board inserted into the board accommodation space while resilient pieces provided in the terminal fittings are resiliently deformed. A predetermined contact pressure is ensured between the terminal fittings and the circuit board by a resilient contact action of the resilient pieces. Further, dimensional tolerances of the housing, the terminal fittings and the circuit board are absorbed by resilient deformation of the resilient pieces. Thus, a structure configured to come into contact with the circuit board while the resilient pieces are resiliently deformed is necessary to ensure contact reliability between the terminal fittings and the circuit board. 
     However, providing the structure that contacts the circuit board while the resilient pieces are resiliently deformed means that corner edge parts on a leading end in an inserting direction of the circuit board butt against the resilient pieces and are strongly abraded against the resilient pieces in the process of inserting the circuit board into the board accommodation space. Such butting and abrasion may cause improper deformation of the resilient pieces, plating peeling on contact portions of the resilient pieces, jamming of shaving from a part of the corner edge part of the circuit board between the resilient pieces and the circuit board and, eventually, a contact failure. 
     The present invention was completed based on the above situation and aims to prevent a reduction of contact reliability. 
     SUMMARY 
     A first aspect of the invention is directed to a card edge connector with a first housing formed with a board accommodation space open forward. At least one terminal fitting is provided in the first housing and is formed with a resilient contact portion projecting toward the board accommodation space. The card edge connector further has a second housing including a circuit board to be inserted into the board accommodation space from the front of the first housing. A guide slope made of synthetic resin covers a leading edge of the circuit board in an inserting direction into the board accommodation space and is inclined with respect to the inserting direction into the board accommodation space. 
     An event that causes a reduction of contact reliability may occur on the resilient contact portion and the circuit board if a corner edge part on a leading end in the inserting direction of the circuit board comes into contact with the resilient contact portion in the process of inserting the circuit board into the board accommodation space. However, the resilient contact portion of the card edge connector of the invention only slides in contact with the guide slope made of synthetic resin and inclined with respect to the inserting direction and does not contact the leading edge in the inserting direction of the circuit board. Thus, there is no possibility of reducing contact reliability. 
     A second aspect of the invention is directed to a method for manufacturing a card edge connector with a first housing formed that has a board accommodation space open forward. At least one terminal fitting is provided in the first housing and is formed with a resilient contact portion projecting toward the board accommodation space. The card edge connector further has a second housing including a circuit board to be inserted into the board accommodation space from the front of the first housing. A board holding member made of synthetic resin surrounds an area of the circuit board except a leading end part in the inserting direction. A guide member made of synthetic resin is configured separately from the board holding member and covers a leading edge of the board holding member in the inserting direction into the board accommodation space on the leading end part in the inserting direction of the board holding member and includes a guide slope inclined with respect to the inserting direction into the board accommodation space. The method is characterized in that the board holding member is molded to embed a part of the guide member except a leading end part in the inserting direction therein after the guide member is attached to a leading end part of the circuit board. 
     Further, in the method for manufacturing a card edge connector according to the invention, the board holding member is molded with a part of the guide member embedded after the guide member is attached to the leading end part of the circuit board. Thus, the guide member can be held reliably without being detached from the circuit board. 
     The second housing may include a board holding member made of synthetic resin and configured to surround an area of the circuit board except a leading end part in the inserting direction, and the guide slope may be formed on a component separate from the board holding member. According to this configuration, the material of the guide slope can be selected regardless of the board holding member. The guide slope may be formed of a synthetic resin material containing no glass fiber. According to this configuration, a coating of the resilient contact portion can be prevented from being scraped. 
     The guide slope may be formed on a guide member, and the guide member may be formed with a pair of covering portions configured to sandwich a leading edge part in the inserting direction of the circuit board in a plate thickness direction. According to this configuration, the covering portions sandwich the leading edge part in the inserting direction of the circuit board in the plate thickness direction. Thus, there is no possibility of a displacement of the guide slope in the plate thickness direction with respect to the circuit board. 
     The covering portion may be formed with a guiding slope inclined with respect to the inserting direction of the circuit board. A step is formed between the covering portion and the circuit board. However, since the covering portion is formed with the guiding slope, the resilient contact portion neither strongly butts against nor is abraded against the covering portion in the process of pulling out the circuit board from the board accommodation space. 
     A leading end part in the inserting direction of the circuit board may be provided with a guide member including the guide slope, whereas the second housing may include a board holding member made of synthetic resin and configured to surround an area of the circuit board except a leading end part in the inserting direction, and a part of the guide member except a leading end part in the inserting direction may be embedded in the board holding member. According to this configuration, the guide member is less likely to be detached from the circuit board, thereby contributing to an increase of a guide member holding force. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a section showing the process of inserting a circuit board into a board accommodation space in a card edge connector of a first embodiment. 
         FIG. 2  is a partial enlarged section of  FIG. 1 . 
         FIG. 3  is a section showing a state where the circuit board is inserted in the board accommodation space. 
         FIG. 4  is a plan view of a second housing. 
         FIG. 5  is a side view of the second housing. 
         FIG. 6  is a partial enlarged section of the second housing. 
         FIG. 7  is a partial enlarged section of a second housing in a card edge connector of a second embodiment. 
         FIG. 8  is a plan view showing a state before a guide member is attached to a circuit board in a card edge connector of a third embodiment. 
         FIG. 9  is a plan view showing a state where the guide member is attached to the circuit board. 
         FIG. 10  is a plan view partly in section of a second housing. 
         FIG. 11  is a plan view showing a second housing in a card edge connector of a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a first embodiment of the invention is described with reference to  FIGS. 1 to 6 . A card edge connector A of this first embodiment includes a first housing  10  and a second housing  20 . 
     &lt;First Housing  10 &gt; 
     The first housing  10  is configured by mounting an inner housing  14  made of synthetic resin into an outer housing  11  made of synthetic resin and has a substantially rectangular front shape long in a lateral direction (width direction) as a whole. The outer housing  11  includes a housing accommodating portion  12  in the form of a rectangular tube open forward (leftward in  FIGS. 1 and 2 ) and a tubular fitting portion  13  located forward of the outer peripheral edge of the front end of the housing accommodating portion  12 . 
     The inner housing  14  includes a pair of vertically symmetrical facing portions  15 . A plurality of terminal fittings  17  long and narrow in a front-back direction are accommodated side by side in the width direction in the upper facing portion  15 . The terminal fittings  17  are formed with resilient contact portions  18  projecting from the lower surface (surface facing a board accommodation space  16  to be described later) of the upper facing portion  15 . A plurality of terminal fittings  17  long and narrow in the front-back direction are accommodated side by side in the width direction also in the lower facing portion  15 . The terminal fittings  17  are formed with resilient contact portions  18  projecting from the upper surface (surface facing the board accommodation space  16 ) of the lower facing portion  15 . The inner housing  14  is accommodated into the housing accommodating portion  12  of the outer housing  11  from front and fixed. A space between the pair of upper and lower facing portions  15  serves as the board accommodation space  16  into which a circuit board  23  of the second housing  20  is to be inserted. The board accommodation space  16  is in the form of a slit long in the width direction and open forward. Since the lower surface of the upper facing portion  15  and the upper surface of the lower facing portion  15  are directly facing the board accommodation space  16 , the resilient contact portions  18  of the terminal fittings  17  accommodated in the upper facing portion  15  and the resilient contact portions  18  of the terminal fittings  17  accommodated in the lower facing portion  15  project into the board accommodation space  16 . 
     &lt;Second Housing  20 &gt; 
     The second housing  20  includes a board holding member  21 , the circuit board  23  and a guide member  30 . A leading edge part of the circuit board  23  in an inserting direction into the board accommodation space  16  serves as a connecting edge portion  24 . A plurality of board contact portions  25  capable of contacting the resilient contact portions  18  are arranged in the lateral direction (width direction) on both sides (both upper and lower surfaces) of the connecting edge portion  24 . The circuit board  23  is integrated with the board holding member  21  made of synthetic resin (e.g. epoxy resin) by insert molding. Specifically, most of the area of the circuit board  23  except the connecting edge portion  24  is surrounded by the board holding member  21  and the connecting edge portion  24  projects like a rib from the front surface (right surface in  FIGS. 1, 3 to 5 ) of the board holding member  21  facing the first housing  10 . 
     The guide member  30  is a component separate from the board holding member  21 . The guide member  30  is made of a resin material different from the board holding member  21 . A synthetic resin material containing no glass fiber and having a lower rigidity (i.e. higher flexibility) than the board holding member  21  such as PBT can be used as the material of the guide member  30 , for example, to improve attachability. The guide member  30  is an integral assembly of a wall-like portion  31 , a pair of bilaterally symmetrical side frame portions  32 , a front frame portion  33  and a pair of bilaterally symmetrical protrusions  34 . The wall-like portion  31  has a substantially rectangular shape long and narrow in the lateral direction and includes a slit-like through groove  35 . The pair of side frame portions  32  extend forward from both left and right end parts on the front surface of the wall-like portion  31 . The front frame portion  33  couples the front ends (extending ends) of the both left and right side frame portions  32  and is long and narrow in the lateral direction. The protrusions  34  are cantilevered backward from both left and right end parts of the wall-like portion  31 . 
     The guide member  30  is attached to the board holding member  21  from front. With the guide member  30  attached to the board holding member  21 , the wall-like portion  31  covers the front surface of the board holding member  21  and the connecting edge portion  24  penetrates through the through groove  35 . The side frame portions  32  cover both left and right side edges of the connecting edge portion  24  and the front frame portion  33  covers the front end edge of the connecting edge portion  24 . Further, the protrusions  34  are fitted into mounting grooves  22  formed on both left and right side surfaces of the board holding member  21 , and the guide member  30  is held in a state attached to the board holding member  21  by a known locking structure formed by the protrusions  34  and the mounting grooves  22 . 
     The upper surfaces of the side frame portions  32  and that of the front frame portion  33  are continuous and flush with each other, and the lower surfaces of the side frame portions  32  and that of the front frame portion  33  are continuous and flush with each other. The upper edge of an opening of the through groove  35  is located at the same height as or slightly lower than the upper surfaces of the side frame portions  32  and the front frame portion  33 . The lower edge of the opening of the through groove  35  is located at the same height as or slightly higher than the lower surfaces of the side frame portions  32  and the front frame portion  33 . The upper surfaces of the side frame portions  32  and the front frame portion  33  are located at the same height as or slightly higher than that of the connecting edge portion  24 , and the lower surfaces of the side frame portions  32  and the front frame portion  33  are located at the same height as or slightly lower than that of the connecting edge portion  24 . 
     The front frame portion  33  is formed with a pair of vertically symmetrical guide slopes  36 . The guide slopes  36  are arranged on the front end edge of the front frame portion  33 , i.e. before the board contact portions  25  in the inserting direction of the circuit board  23  into the board accommodation space  16 . The guide slope  36  on an upper surface side is inclined downwardly in the inserting direction into the board accommodation space  16 , and the guide slope  36  on a lower surface side is inclined upwardly in the inserting direction into the board accommodation space  16 . That is, a vertical distance between the upper and lower guide slopes  36  is gradually reduced toward a front side in the inserting direction. Further, the guide slopes  36  are formed over the entire width of the front frame portion  33 . 
     The second housing  20  is fitted into the tubular fitting portion  13  from front of the first housing  10 . With the second housing  20  fitted in the tubular fitting portion  13 , the connecting edge portion  24  of the circuit board  23  is inserted in the board accommodation space  16 . With the connecting edge portion  24  inserted in the board accommodation space  16 , the resilient contact portions  18  arranged to vertically sandwich the connecting edge portion  24  resiliently come into contact with the board contact portions  25  of the connecting edge portion  24 . In this way, the terminal fittings  17  of the first housing  10  and the circuit board  23  of the second housing  20  are conductively connected. 
     The card edge connector A of this first embodiment includes the first housing  10  formed with the board accommodation space  16  open forward, the terminal fittings  17  provided in the first housing  10  and formed with the resilient contact portions  18  projecting toward the board accommodation space  16 , and the second housing  20  including the circuit board  23  to be inserted into the board accommodation space  16  from front of the first housing  10 . In a state where the circuit board  23  is not inserted in the board accommodation space  16  and the resilient contact portions  18  are not resiliently deflected, a minimum interval (minimum facing distance) between the resilient contact portions  18  vertically facing each other in the board accommodation space  16  is set smaller than a plate thickness (vertical dimension) of the connecting edge portion  24 . By this dimensional difference, the resilient contact portions  18  come into contact with the connecting edge portion  24  while being resiliently deflected to ensure a predetermined contact pressure when the connecting edge portion  24  is inserted into the board accommodation space  16 . 
     Making the minimum facing distance between the resilient contact portions  18  and the plate thickness of the circuit board  23  (connecting edge portion  24 ) different means that the corner edge part on the leading end in the inserting direction of the connecting edge portion  24  butts against the resilient contact portions  18  and are strongly abraded against the resilient contact portions  18  in the process of inserting the circuit board  23  into the board accommodation space  16 . Such butting and abrasion cause improper deformation of the resilient contact portions  18 , plating peeling on contact portions of the resilient contact portions  18 , the jamming of shaving from a part of the corner edge part of the connecting edge portion  24  between the resilient contact portions  18  and the circuit board  23 . Such events cause a contact failure between the resilient contact portions  18  and the board contact portions  25  of the circuit board  23 . 
     As a countermeasure against that, the card edge connector A of this first embodiment is provided with the guide slopes  36  to cover the leading edge of the circuit board  23  (front end edge of the connecting edge portion  24 ) in the inserting direction into the board accommodation space  16 . The guide slopes  36  are made of a synthetic resin material softer than the circuit board  23  (connecting edge portion  24 ) or a synthetic resin material having a lower rigidity than the circuit board  23  (connecting edge portion  24 ) to protect contacts. For example, if the circuit board  23  is a glass epoxy board, the guide slopes  36  can be made of synthetic resin containing no glass fiber. The guide slopes  36  are inclined with respect to the inserting direction into the board accommodation space  16 . Thus, in the process of inserting the connecting edge portion  24  into the board accommodation space  16 , the resilient contact portions  18  are gradually resiliently deflected while sliding in contact with the tapered guide slopes  36  without contacting the corner edge part on the front end of the connecting edge portion  24 . 
     As just described, in the card edge connector A of this first embodiment, the butting of the connecting edge portion on the leading end in the inserting direction of the circuit board  23  against the resilient contact portions  18  and strong abrasion of this connecting edge portion against the resilient contact portions  18  are avoided in the process of inserting the circuit board  23  into the board accommodation space  16 . That is, in the inserting process of the circuit board  23 , events that cause a reduction of contact reliability do not occur on the resilient contact portions  18  and the circuit board  23 . Thus, according to the card edge connector A of this first embodiment, a contact failure between the resilient contact portions  18  and the circuit board  23  can be prevented. 
     Further, the second housing  20  includes the board holding member  21  made of synthetic resin and configured to surround areas of the circuit board  23  except the leading end part (connecting edge portion  24 ) in the inserting direction, and the guide slopes  36  are formed on the component (guide member  30 ) separate from the board holding member  21 . According to this configuration, the material of the guide slopes  36  can be selected regardless of the board holding member  21 . Further, the guide slopes  36  may be made of a synthetic resin material containing no glass fiber. According to this configuration, coatings of the resilient contact portions  18  can be prevented from being scraped unlike in the case of using a synthetic resin containing glass fibers. 
     Next, a second embodiment of the invention is described with reference to  FIG. 7 . In a card edge connector B of this second embodiment, a guide member  40  differs in configuration from the guide member  30  of the above first embodiment. Since the other components are the same as in the above first embodiment, they are denoted by the same reference signs and structures, functions and effects thereof are not described. 
     The guide member  40  of this second embodiment and the guide member  30  of the first embodiment differ only in the configurations of side frame portions  41  and a front frame portion  42 . Specifically, in the guide member  30  of the first embodiment, the upper surfaces of the side frame portions  32  and the front frame portion  33  are located substantially at the same height as that of the connecting edge portion  24 , and the lower surfaces of the side frame portions  32  and the front frame portion  33  are located substantially at the same height as that of the connecting edge portion  24 . In contrast, in the guide member  40  of this second embodiment, the upper surfaces of the side frame portions  41  and the front frame portion  42  are set higher so that a clear step is formed between the upper surfaces of the side frame portions  41  and the front frame portion  42  and that of a connecting edge portion  24 . Further, the lower surfaces of the side frame portions  41  and the front frame portion  42  are set lower so that a clear step is formed between the lower surfaces of the side frame portions  41  and the front frame portion  42  and that of the connecting edge portion  24 . 
     Further, the front frame portion  42  is formed with a covering portion  43  for covering the front end edge on the upper surface of the connecting edge portion  24  and a covering portion  43  for covering the front end edge on the lower surface of the connecting edge portion  24 . The upper surface of the upper covering portion  43  is continuous and flush with that of the front frame portion  42 , and the lower surface of the lower covering portion  43  is continuous and flush with that of the front frame portion  42 . A guiding slope  44  inclined with respect to an inserting direction of a circuit board  23  is formed on a rear edge part of the upper covering portion  43 . This upper guiding slope  44  is inclined downwardly toward a rear side in the inserting direction conversely to an upper guide slope  36 . Further, a guiding slope  44  inclined with respect to the inserting direction of the circuit board  23  is also formed on a rear edge part of the lower covering portion  43 . This lower guiding slope  44  is inclined upwardly toward the rear side in the inserting direction conversely to a lower guide slope  36 . 
     According to the card edge connector B of this second embodiment, since a pair of upper and lower covering portions  43  sandwich the front end edge of the connecting edge portion  24  in a plate thickness direction (vertical direction), a displacement of the front frame portion  42  (guide slope  36 ) in the plate thickness direction with respect to the connecting edge portion  24  can be prevented. Further, the steps are formed between the front frame portion  42  and the connecting edge portion  24  by forming the covering portions  43 . In view of this point, the guiding surfaces  44  are formed on the rear edge part of the covering portions  43 . Since this causes resilient contact portions  18  to slide in contact with the guiding slopes  44  in the process of pulling out the circuit board  23  from the board accommodation space  16 , the resilient contact portions  18  neither strongly butt against nor are abraded against the covering portions  43 . Thus, plating peeling, improper deformation and the like of the resilient contact portions  18  do not occur also in pulling out the circuit board  23 . 
       FIGS. 8 to 10  show a card edge connector A according to a third embodiment of the present invention. 
     In the first and second embodiments, the board holding member  21  is molded with the circuit board  23  inserted and, thereafter, the guide member  30  is attached. However, in this third embodiment, a guide member  30  is attached to a circuit board  23  in advance and a board holding member  21  is molded with that assembly inserted. The configuration of the guide member  30  according to this third embodiment is basically the same as the guide member  30  of the first embodiment. 
       FIG. 8  shows an operation status in attaching the guide member  30  to a connecting edge portion of the circuit board  23 . As shown in  FIG. 8 , the guide member  30  includes a wall-like portion  31  having a through groove  35 , a pair of side frame portions  32  extending forward from both left and right end parts of the front surface of the wall-like portion  31  and a front frame portion  33  coupling extending end edges of the both side frame portions  32  and having a pair of upper and lower guide slopes  36 . Further, a pair of retaining projections  37  are formed to project on both left and right end parts of the rear surface of the wall-like portion  31 . 
     In manufacturing the card edge connector A, the guide member  30  is first attached to the circuit board  23 . In that case, the guide member  30  has the connecting edge portion  24  of the circuit board  23  inserted into the through groove  35  of the wall-like portion  31 . With the guide member  30  properly attached to the circuit board  23 , the front frame portion  33  is held in close contact along the leading edge of the circuit board  23  and the both side frame portions  32  are held in close contact along both left and right side edges of the circuit board  23 . 
     An assembly obtained by attaching the guide member  30  to the circuit board  23  in this way is set in a mold (not shown) for molding the board holding member  21  and molten resin is filled into a mold interior in that state. A cut-off groove (not shown) for the mold is formed by recessing the wall-like portion  31  over the entire peripheral edge, and the circuit board  23  and the guide member  30  located before the cut-off groove are exposed outside the mold and a part behind the cut-off groove including the both retaining projections  37  is accommodated in the mold when the mold is closed with the cut-off groove as a boundary. 
     A second housing  20  taken out after insert molding is completed in this way is molded such that a rear half of the circuit board  23  is embedded together with the both retaining projections in the board holding member  21 . That is, since the guide member  30  is united with the board holding member  21  while being attached to the circuit board  23  by coupling the both retaining projections  37  and a rear half of the wall-like portion  31  in the guide member  30  to the board holding member  21 , the guide member  30  is firmly held so as not to be detached from the circuit board  23  and a holding force is increased. 
       FIG. 11  shows a card edge connector A according to a fourth embodiment of the present invention. In this fourth embodiment, the procedure of manufacturing a second housing  20  is similar to that of manufacturing the second housing  20  of the third embodiment, and the fourth embodiment differs only in the shape of a guide member  30 . 
     In this fourth embodiment, the guide member  30  is made of synthetic resin and formed into a substantially rectangular frame fittable along the outer peripheral surface of the circuit board  23 . That is, the guide member  30  is composed of a front frame portion  33 , a pair of side frame portions  32  and a rear frame portion  38  extending along the rear edge of a circuit board  23 , but does not include the wall-like portion  31  and the retaining projections  37  unlike in the third embodiment. 
     In this fourth embodiment, the guide member  30  is embedded in a board holding member  21  except a front area (area indicated by dotted line in  FIG. 11  is an embedded part) as shown in  FIG. 11  in a state where the board holding member  21  is molded. Thus, the guide member  30  is firmly held so as not to be detached from the circuit board  23  and a holding force is increased as in the third embodiment. 
     The invention is not limited to the above described and illustrated embodiments. For example, the following embodiments are also included in the scope of the invention. 
     Although the terminal fittings are provided to face each other across the circuit board (board accommodation space) in the above first and second embodiment, the terminal fittings may be arranged on one side to face only one of the both sides of the circuit board. 
     Although the guide slopes and the board holding member are made of different materials in the above first and second embodiments, the guide slopes and the board holding member may be made of the same material. 
     Although the component (guide member) formed with the guide slopes is separate from the board holding member in the above first and second embodiments, the guide slopes may be integrally formed on the board holding member. 
     Although the guide slopes are made of the synthetic resin containing no glass fiber in the above first and second embodiments, the guide slopes may be made of synthetic resin containing glass fibers. 
     In the third embodiment, the guide member includes the wall-like portion as in the first embodiment. However, the guide member may not include the wall-like portion. 
     Although the guide member is formed with the retaining projections and the guide member and the board holding member are physically coupled in the third embodiment, the retaining projections can be omitted. In that case, if the board holding member and the guide member are made of the same resin material, good adhesion is obtained on interfaces of the board holding member and the guide member, which is effective in ensuring a guide member holding force. 
     Although the guide member is continuous over the entire circumference in the above embodiment, the guide member may be, for example, divided into two pieces that can be united. 
     LIST OF REFERENCE SIGNS 
     
         
         A . . . card edge connector 
           10  . . . first housing 
           16  . . . board accommodation space 
           17  . . . terminal fitting 
           18  . . . resilient contact portion 
           20  . . . second housing 
           21  . . . board holding member 
           23  . . . circuit board 
           31  . . . wall-like portion (part to be embedded in board holding member) 
           36  . . . guide slope 
           37  . . . retaining projection (part to be embedded in board holding member) 
         B . . . card edge connector 
           40  . . . guide member 
           43  . . . covering portion 
           44  . . . guiding slope