Patent Publication Number: US-8118609-B2

Title: Electrical connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT International Application No. PCT/JP2009/004407 filed Sep. 7, 2009, which claims priority under 35 U.S.C. §119 to Japanese Patent Application No. JP 2008-240511, filed Sep. 19, 2008. 
    
    
     FIELD OF INVENTION 
     The present invention relates to an electrical connector and in a particular to an electrical connector having a short-circuit terminal for short-circuiting connecting signal transmission terminals. 
     BACKGROUND 
     An electrical connector for an air bag used in an automobile includes a male connector and a female connector. Male terminals for signal transmission positioned in the male connector are connected to a signaling side, such as a shock sensor, while female terminals for signal transmission in the female connector are connected to an apparatus side, such as an air bag unit. The connector has a function, among others, of short-circuiting the female terminals in order to prevent malfunction due to an accidental current flow to the apparatus side when the male connector and the female connector are separated from each other. The connector also has a function of breaking the short circuit between the female terminals when the male connector and the female connector are mated with each other (see Japanese Patent Laid-Open No. 9-50850, for example). 
     As shown in  FIGS. 10 and 11 , a known female connector  100  in which adjacent female terminals  120  are short-circuited includes a housing  110  having a plurality of terminal receiving cavities  111  for receiving female terminals  120  therein and the female terminals  120  received in the respective terminal receiving cavities  111  and locked by corresponding lances  112 . The female terminal  120  has a contact piece  120   a  formed by folding back a front end part of the female terminal  120  and a contact protrusion  120   b  protruding to the inside of the terminal receiving cavity  111 . A male terminal of a male connector (not shown) is electrically connected to the female terminal  120 . An upper surface of the male terminal is in contact with the contact piece  120   a  and the lower surface is in contact with the contact protrusion  120   b . The housing  110  has, at the front thereof, male terminal inlets  113  formed at positions corresponding to the positions of the terminal receiving cavities  111 . In Japanese Patent Laid-Open No. 9-50850, a side of the female connector at which the male connector is mated therewith is defined as a front side, and the opposite side is defined as a rear side. 
     The female connector  100  has a U-shaped short-circuit terminal for short-circuiting a pair of female terminals  120  that are adjacent to each other in the width direction. As shown in Japanese Patent Laid-Open No. 9-50850, the conventional short-circuit terminal has a bent part formed at the rear thereof and a contact formed at the front thereof that is to come into direct contact with a female terminal, and the section from the bent part to the contact functions as a spring. The contact comes into elastic contact with the lower surface of the contact protrusion  120   b  of the female terminal  120  through a window  114  formed in a front part of the housing. Then, as shown by the arrow A in  FIG. 10 , an upward force is applied to the female terminal  120 . 
     For the conventional female connector  100 , the lances  112  are disposed above the female terminals  120  to which an upward force is applied. However, the lances  112  are elastically deformable and therefore cannot adequately absorb the upward force. As a result, the female terminals  120  are deformed to be bent upward, and the contact between the contacts and the female terminals  120  is unstable. Thus, there is a possibility that the short circuit between the paired female terminals  120  is broken, and a current may accidentally flow to the apparatus side, which causes malfunction. 
     If a housing wall that supports the female terminals  120  is formed at the front of the lances  112 , the upward displacement of the female terminals  120  can be prevented. Actually, however, a mold member for forming the lances  112  has to be placed at the front of the lances  112 , and therefore the housing wall cannot be formed at the front of the lances  112 . 
     In addition, as a component of an automobile, there is a demand for minimizing the female connector  100 . To meet the demand, the lance  112 , which is a component of the female connector  100 , also has to be reduced in size. However, if the size of the lance  112  is reduced, the strength of the lance  112  decreases, and the female terminal  120  is more easily deformed and bent upward. 
     In addition, for the known female connector  100 , the window  114  is formed over a front end part of the terminal receiving cavities  111 . Thus, as shown in  FIG. 11 , the female terminal  120  is held by the housing  110  only at the opposite side surfaces in the width direction. As a result, the female terminal  120  is likely to rotate about the axis thereof and be displaced. As the displacement becomes significant, the female terminals  120  is unable to smoothly mate with the male terminals. 
     SUMMARY 
     The present invention has been devised in view of such technical problems, and an object of the present invention, among others, is to provide a connector that can provide stable contact between a signal transmission terminal and a short-circuit terminal and prevent rotation of the signal transmission terminal about an axis thereof even if the connector is downsized. 
     To achieve the object described above, a connector according to the invention includes a main body having a plurality of terminal receiving cavities provided with lances by which signal transmission terminals are secured and a plurality of short-circuit terminal receiving cavities adjacent to the terminal receiving cavities for receiving short-circuit terminals. Each short-circuit terminal includes a bent part at a forward position and a contact at a rearward position. The main body further includes a window that is formed at a position to the rear of the lances corresponding to the contacts of the short-circuit terminals and through which the terminal receiving cavities and the short-circuit terminal receiving cavities communicate with each other. The contacts of the short-circuit terminals are in contact with the female terminals through the window. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail in the following with reference to the embodiments shown in the drawings. Similar or corresponding details in the Figures are provided with the same reference numerals. The invention will be described in detail with reference to the following figures of which: 
         FIG. 1  is a front perspective view of a female connector according to the invention; 
         FIG. 2  is a rear perspective view of the female connector according to the invention; 
         FIG. 3  is a front view of the female connector according to the invention; 
         FIG. 4  is a sectional view of the female connector taken along the line indicated by the arrows  4  in  FIG. 3 ; 
         FIG. 5  is a sectional view of the female connector taken along the line indicated by the arrows  5  in  FIG. 4 ; 
         FIG. 6  is a side view of the female connector according to the invention; 
         FIG. 7  is a sectional view of the female connector taken along the line indicated by the arrows  7  in  FIG. 6 ; 
         FIG. 8  is a front view of the female connector according to the invention mated with male connector; 
         FIG. 9  is a sectional view of the female connector according to the invention and the male connector taken along the line indicated by the arrows  9  in  FIG. 8 ; 
         FIG. 10  is a sectional view of a known female connector; and 
         FIG. 11  is a sectional view of the female connector taken along the line indicated by the arrows  11  in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     In the following, an embodiment of the present invention will be described with reference to  FIGS. 1 to 9 . 
     In general, the shown embodiment relates to a connector used for an air bag for an automobile. However, other applications of the invention are possible. 
     A female connector  10  according to the invention includes a connector main body  20  and a housing  40  that houses the connector main body  20 . The female connector  10  is to be mated with a male connector  60  described later. 
     A female terminal  11  (i.e. signal transmission terminal) of the female connector  10  is connected to an apparatus side of an air bag unit, and a male terminal  63  of the male connector  60  is connected to a signaling side, such as a shock sensor. 
     The connector main body  20  has a sub-housing  21  in which a plurality of terminal receiving cavities  22  for receiving a plurality of female terminals  11  therein are formed. The sub-housing  21  is integrally molded with the connector main body  20  from a resin material by injection molding in the embodiment shown. The terminal receiving cavities  22  are formed to penetrate the sub-housing  21  in the front-back direction of the sub-housing  21 . Male terminal inlets  32  are formed in a front end part of the sub-housing  21  at positions corresponding to the positions of the terminal receiving cavities  22 . Additionally, the sub-housing  21  has elastically deformable lances  23  facing the terminal receiving cavities  22 . The female terminal  11  is secured by the lance  23 . The female terminal  11  is also further secured when the connector main body  20  is fit into the housing  40 . 
     The female terminal  11  is formed by stamping and bending a metal material that has both high strength and high conductivity. The female terminal  11  has a contact piece  11   a  formed by folding back a front end part thereof and a contact protrusion  11   b  protruding to the inside of the cavity  22 . The male terminal  63  of the male connector  60  is electrically connected to the female terminal  11 , wherein the upper surface of the male terminal  63  is in contact with the contact piece  11   a  and the lower surface is in contact with the contact protrusion  11   b . In  FIG. 4 , illustration of the female terminals  11  positioned in the terminal receiving cavities  22  in the lower two rows is omitted. 
     According to the invention, two adjacent female terminals  11  received in the terminal receiving cavities  22  in the uppermost row may be paired. For instance, in the embodiment shown in Figures, there are eight cavities  22  in the uppermost row, and thus, there are four pairs of female terminals  11  in total. When the female connector  10  is separated from the male connector  60 , the paired female terminals  11  are short-circuited, thereby preventing an accidental current flow to the air bag side. When the female connector  10  and the male connector  60  mate with each other, the short circuit between the paired female terminals  11  is broken. 
     Short-circuit terminal receiving cavities  24  for accommodating the U-shaped short-circuit terminals  12  therein are formed in a front part of the sub-housing  21 . In the embodiment shown, the short-circuit terminal receiving cavities  24  are formed below the terminal receiving cavities  22  in the uppermost row. Four cavities  24  are arranged in the width direction of the sub-housing  21 , with each cavity  24  associated with two cavities  22 . The sub-housing  21  has a window  25  positioned to the rear of the lance  23  and through which the cavities  22  in the uppermost row and the cavities  24  communicate with each other. 
     The sub-housing  21  has a retainer insertion passageway  26  formed to the rear of the cavities  24 . The retainer insertion passageway  26  is formed in the width direction of the sub-housing  21  perpendicular to the front-rear direction of the sub-housing  21 . The retainer insertion passageway  26  communicates with the cavities  22  in the rows above and below the cavities  24 . A retainer  43  formed on the housing  40  is inserted into the retainer insertion passageway  26 . When the retainer  43  is inserted to a proper position in the retainer insertion passageway  26 , the female terminals  11  are secondarily locked by the retainer  43 . 
     The sub-housing  21  has a guide groove  27  formed in the upper surface and guide grooves  28  and  29  formed in the lower surface. The guide grooves  27 ,  28  and  29  are formed in the width direction of the sub-housing  21 . 
     The short-circuit terminal  12  is formed by stamping and bending a metal material that has both high strength and high conductivity. The short-circuit terminal  12  has a bottom plate  13  to be fixed to the bottom surface of the cavity  24 . The short-circuit terminal  12  further has a U-shaped bent part  14  formed by upwardly folding back a front end part of the bottom plate  13  and a spring  15  extending rearward from the bent part  14 . The spring  15  has a contact  16  formed to protrude upward. In short, the short-circuit terminal  12  has the bent part  14  at the front thereof and the contact  16  at the rear thereof. 
     A positioning passageway  13   a  (see  FIG. 5 ) is formed in the bottom plate  13 , and a positioning protrusion  31  formed on the bottom surface of the cavity  24  is fit into the positioning passageway  13   a  to secure the short-circuit terminal  12  to the sub-housing  21 . 
     The spring  15  branches into two sections. As a result, one short-circuit terminal  12  has two contacts  16 . When the female connector  10  is separated from the male connector  60 , the two contacts  16  maintain contact with the lower surfaces of the paired two female terminals  11  through the window  25 . As a result, the paired two female terminals  11  are short-circuited. When the female connector  10  is mated with the male connector  60 , a short-circuit breaking protrusion  62  formed on the male connector  60  is inserted between the lower surface of the female terminal  11  and the contacts  16  to press the contacts  16  down, thereby breaking the short-circuit (see  FIG. 9 ). 
     The housing  40  has a connector receiving cavity  41  (referred to as a cavity  41  hereinafter) for receiving the connector main body  20  therein. The housing  40  is also integrally molded from a resin material by injection molding. 
     The cavity  41  has an opening on one side in the width direction of the housing  40 , and the connector main body  20  is inserted into the cavity  41  through the opening. The housing  40  has a plurality of male terminal inlets  42  formed in the front end surface thereof at positions corresponding to the male terminal inlets  32  of the connector main body  20 . The male terminals  63  of the male connector  60  are connected to the female terminals  11  through the male terminal inlets  42  and the male terminal inlets  32 . 
     The retainer  43  to be inserted into the retainer insertion passageway  26  of the connector main body  20  is formed in the cavity  41  of the housing  40 . The retainer  43  protrudes from the inner surface of a side wall  44  of the housing  40  opposite to the side where the opening is formed. When the connector main body  20  is fit into the housing  40 , an engaging end  11   c  of the female terminal  11  abuts against the front end surface of the retainer  43 , and thereby the female terminal  11  is secondarily secured. 
     The housing  40  has guide protrusions  47 ,  48  and  49  extending into the cavity  41 . When the connector main body  20  is inserted into the cavity  41  of the housing  40 , the guide protrusion  47  is inserted into the guide groove  27 , the guide protrusion  48  is inserted into the guide groove  28 , and the guide protrusion  49  is inserted into the guide groove  29 , thereby guiding the connector main body  20  to a predetermined position in the cavity  41 . 
     The housing  40  has a lock  45  positioned to the rear of the retainer  43  in the cavity  41  (see  FIG. 7 ). The lock  45  protrudes from the inner surface of the side wall  44  of the housing  40 . The lock  45  has an engaging protrusion  46  protruding upward formed at the tip end thereof, and the engaging protrusion  46  is engaged with an engaging groove  30  formed in the sub-housing  21  to prevent the connector main body  20  from falling off the housing  40 . 
     For the female connector  10 , the short-circuit terminals  12  are inserted into the cavities  24  of the sub-housing  21  from the front. When the female terminals  11  are inserted into the cavities  22  of the sub-housing  21  from the rear, the female terminals  11  are secured by the flexible lances  23 . The paired female terminals  11  come into contact with the contacts  16  of the short-circuit terminals  12  and are thereby short-circuited. Although the cavities  22  located above the cavities  24  have been described above, the female terminals  11  received in the cavities  22  below the cavities  24  are also secured by the lances  23 . 
     The connector main body  20  provided with the female terminals  11  and the short-circuit terminals  12  is inserted into the cavity  41  through the opening of the housing  40 . In this operation, the retainer  43  is inserted into the retainer insertion passageway  26  of the connector main body  20 . When the connector main body  20  is inserted to a proper position, the engaging protrusion  46  formed at the tip end of the lock  45  is engaged with the engaging groove  30  of the sub-housing  21  to prevent the connector main body  20  from falling off the sub-housing  21 . In addition, the engaging ends  11   c  of the female terminals  11  abut against the front end surface of the retainer  43 , and thereby the female terminals  11 , which have been secured by the lances  23 , are further secured. 
     When the female connector  10  according to the invention is mated with the male connector  60 , the male terminals  63  held in the housing  61  of the male connector  60  and the female terminals  11  held in the connector main body  20  of the female connector  10  are electrically connected to each other. When mated, the short-circuit breaking protrusions  62  formed on the housing  61  of the male connector  60  are inserted between the contacts  16  of the short-circuit terminals  12  and the female terminals  11  to press the contacts  16  down, thereby breaking the short-circuit of the paired female terminals  11  (see  FIG. 9 ). 
     Characteristics of the female connector  10  according to the embodiment described above will be described in comparison with the known female connector  100 . 
     For the known female connector  100 , the elastically deformable lance  112  cannot adequately absorb the upward force applied to the female terminal  120 . Thus, the female terminal  120  is likely to be deformed to be bent upward. As a result, the contact between the short-circuit terminal and the female terminal  120  is unstable. 
     To the contrary, as shown in  FIG. 4 , for the female connector  10  according to the invention, the bent part  14  of the short-circuit terminal  12  is positioned forward, and the contacts  16  of the short-circuit terminal  12  are located to the rear of the lance  23 . An upper supporting wall  21   a  that defines the cavity  22  is formed above the contacts  16 . The upper supporting wall  21   a  is more rigid than the lance  23 , and therefore, the female terminal  11  is less likely to be deformed upward even if an upward force is applied to the female terminal  11  by the short-circuit terminal  12 , for example. Therefore, contact between the female terminal  11  and the short-circuit terminal  12  is stable. As a result, the short circuit between the paired female terminals  11  can be stably maintained. 
     For the known female connector  100 , the contact of the short-circuit terminal is in contact with the lower surface of the contact protrusion  120   b  of the female terminal  120 . As shown in  FIG. 11 , the lower surface of the contact protrusion  120   b  is inclined at the opposite sides. If the contact protrusion  120   b  is in contact with the short-circuit terminal at the inclined surface, the contact area is insufficient, and the electrical connection between the short-circuit terminal and the female terminal  120  is also insufficient. 
     To the contrary, for the female connector  10  according to the invention, the contacts  16  are positioned to the rear of the lance  23 . Since the contact protrusion  11   b  is displaced from the position corresponding to the contacts  16 , the lower surface of the bottom plate  13  is flat at that position. Therefore, the female connector  10  according to the invention has a sufficient contact area between the contacts  16  and the female terminals  11 , and therefore, the short circuit between the paired female terminals  11  can be stably maintained. 
     For the known female connector  100 , as shown in  FIG. 11 , the window  114  is formed in the front end of the housing  110 . As a result, the female terminal  120  is inadequately held at the front end, so that the female terminal  120  may rotate about the axis thereof and be displaced from the proper position. As the displacement becomes significant, it is difficult to smoothly mate the female terminals  120  with the male terminals. 
     To the contrary, for the female connector  10  according to the invention, there is a lower supporting wall  21   b  that supports the lower surface of the female terminal  11  at the front end of the sub-housing  21  (see  FIG. 5 ). Therefore, at the front end of the sub-housing  21 , the female terminal  11  is held not only at the opposite side surfaces in the width direction but also at the lower surface, so that the female terminal  11  is less likely to rotate about the axis thereof and is not significantly displaced. Thus, the female terminals  11  can be smoothly connected to the male terminals  63 . 
     For the known female connector  100 , in manufacturing of the housing  110  by injection molding, a molding pin P for forming the window  114  is inserted from the front (see  FIG. 10 ). If the molding pin P is placed below the male terminal inlet  113  during injection molding, the thickness and strength of a lower wall  113   a  decreases accordingly. As the thickness of the wall  113   a  decreases, the length of an inclined surface T formed at the front end of the lower wall  113   a  decreases. As a result, the area for receiving the male terminal  63  decreases, and the possibility of failing to guide the male terminal  63  into the male terminal inlet  113  increases. If the female connector  10  and the male connector  60  are forcedly mated with each other when the tip ends of the male terminals  63  abut against the inclined surfaces T, the male terminals  63  may damage the wall  113   a.    
     To the contrary, for the female connector  10  according to the invention, the retainer insertion passageway  26  extending in the width direction is formed in the sub-housing  21  of the connector main body  20  (see  FIG. 4 ). To form the retainer insertion passageway  26  during the injection molding, a molding pin to form the retainer insertion passageway  26  is inserted in the width direction. If the molding pin has a shape corresponding not only to the retainer insertion passageway  26  but also to the window  25 , the window  25  can be formed without the molding pin inserted from the front. In this case, unlike the known female connector  100 , the thickness of a lower wall  32   a  of the male terminal inlet  32  does not decrease. As a result, compared with the known connector  100 , the area for receiving the male terminal  63  increases, and the possibility that the male terminals  63  abut against and damage the wall  32   a  decreases. 
     Although an embodiment of the invention has been described above, the invention should not be construed as being limited to the embodiment. Although the embodiment described above relates to a connector used for an air bag, the present invention can be widely applied to a connector provided with signal transmission terminals to be short-circuited and a short-circuit terminal. The female terminals  11  to be short-circuited are not limited to those in the uppermost row in the sub-housing  21 , and the female terminals  11  disposed in the lowermost row can also be short-circuited. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.