Patent Publication Number: US-11658446-B2

Title: Relay connector and busbar

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application corresponds Japanese Patent Application No. 2020-210181 filed in the Japan Patent Office on Dec. 18, 2020, the entire disclosure of which incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a relay connector and a busbar that is used in this relay connector. 
     Description of Related Arts 
     In a joint connector disclosed by Japanese Laid-Open Patent Publication No. 2012-99249, a busbar that has a plate-shaped main body portion and a plurality of male terminal portions extending from two sides, which face each other, of the main body portion is used as a busbar that is inserted and removed with respect to a female terminal from both sides in a front-rear direction. 
     In the busbar, the main body portion and the male terminal portions are disposed on the same plane, and therefore a holding force for holding the busbar in a housing becomes low. Therefore, in order to make the holding force high, it is conceivable that the length in the front-rear direction of a portion that holds the busbar is lengthened. However, if the length in the front-rear direction of the portion that holds the busbar is lengthened, a joint connector (which corresponds to a relay connector) is enlarged. 
     SUMMARY OF THE INVENTION 
     One preferred embodiment of the present invention provides a relay connector that is small in size and that has a high holding force by which a busbar is held, and provides a busbar that is used in this relay connector. 
     One preferred embodiment of the present invention provides a relay connector that connects a plurality of front female terminals, which are fitted from a front in a front-rear direction, and a plurality of rear female terminals, which are fitted from a rear in the front-rear direction, together and that includes a housing and a busbar. The housing includes a plurality of front insertion recess portions that are disposed so as to be arrayed in a right-left direction and into which the front female terminals are respectively inserted, a plurality of rear insertion recess portions that are disposed so as to be arrayed in the right-left direction and into which the rear female terminals are respectively inserted, an intermediate wall portion that divides the front insertion recess portion and the rear insertion recess portion from each other in the front-rear direction, and a busbar holding portion that is disposed at the intermediate wall portion. The busbar includes a base portion that extends in the right-left direction, a plurality of rear tabs that extend from the base portion to the rear insertion recess portion, a plurality of extension portions each of which extends from the base portion to a same side in an up-down direction, and a plurality of front tabs each of which extends from an extension end of each of the extension portions to a corresponding one of the front insertion recess portions. Each of the rear tabs includes a rear held portion adjacent to the base portion and a rear male terminal portion that is housed in the rear insertion recess portion. Each of the front tabs includes a front held portion adjacent to the extension end of the extension portion and a front male terminal portion that is housed in the front insertion recess portion. The busbar holding portion includes a plurality of first holding portions which respectively hold the rear held portions the rear tabs, a plurality of second holding portions which respectively hold the front held portions of the front tabs, and a plurality of third holding portions which respectively hold the extension portions. 
     According to this configuration, the busbar holding portion of the housing includes the first holding portion, the second holding portion, and the third holding portion. In the busbar, the rear held portion of the rear tab held by the first holding portion, the front held portion of the front tab held by the second holding portion, and the extension portion held by the third holding portion are disposed in a crank shape, and their crank-shaped portions are connected together through the base portion. Therefore, it is possible to realize a relay connector having a high holding force by which the busbar is held even if the relay connector is small in size. 
     In one preferred embodiment, each of the first holding portions includes a press-fit hole that passes through the intermediate wall portion and into which a corresponding one of the rear held portions is press-fitted and fixed. According to this configuration, the rear held portion of the rear tab is press-fitted and fixed into the press-fit hole serving as the first holding portion, and therefore the busbar is firmly fixed particularly in the front-rear direction. 
     In one preferred embodiment, each of the second holding portions includes a second holding groove that is disposed at a wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion and that holds a corresponding one, which has been fitted in the second holding groove, of the front held portions, and the second holding groove is formed in a shape including a pair of inner wall surfaces that face each other in the up-down direction and that position and hold the front held portion in the up-down direction. 
     According to this configuration, the front held portion of the front tab is fitted and held by the second holding groove serving as the second holding portion disposed at the wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion. The front held portion is positioned and held by the pair of inner wall surfaces of the second holding groove in the up-down direction. The busbar is positioned and held in the up-down direction by use of the front held portion. 
     In one preferred embodiment, each of the front held portions includes a pair of protruding portions that protrude to both sides in the right-left direction, and is formed in a cross shape when seen in the up-down direction. According to this configuration, the busbar is firmly positioned and held in the up-down direction by use of the front held portion assuming the cross shape. 
     In one preferred embodiment, each of the third holding portions includes an abutting portion that is disposed at a wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion and against which a corresponding one of the extension portions is abutted. According to this configuration, the extension portion is abutted against the abutting portion (third holding portion) disposed at the wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion. Therefore, it is possible to highly accurately position and hold the busbar in the front-rear direction by use of the extension portion. 
     In one preferred embodiment, each of the third holding portions includes a third holding groove that is disposed at the wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion and that holds a corresponding one, which has been fitted to the third holding groove, of the extension portions, and the third holding groove is formed in a shape including a grooved bottom surface serving as the abutting portion and a pair of inner wall surfaces that face each other in the right-left direction and that position and hold a corresponding one of the extension portions in the right-left direction. 
     According to this configuration, the extension portion is fitted and held by the third holding groove serving as the third holding portion disposed at the wall surface, which is closer to the front insertion recess portion, of the intermediate wall portion. The extension portion is positioned and held by the pair of inner wall surfaces of the third holding groove in the right-left direction, and the extension portion is positioned and held by the grooved bottom surface of the third holding groove in the front-rear direction. Hence, the busbar is positioned and held in the front-rear direction and in the right-left direction by use of the extension portion. 
     In one preferred embodiment, a plurality of the busbars are disposed so as to be arrayed in the right-left direction, the housing includes a plurality of busbar housing portions that are disposed so as to be arrayed in the right-left direction and into each of which a corresponding one of the busbars is inserted and disposed from the front, each of the busbar housing portions is defined by a pair of partition wall portions that face each other in the right-left direction and by a pair of wall portions that face each other in the up-down direction, and the base portions of the busbars housed in the busbar housing portions adjacent in the right-left direction are insulated from each other by the partition wall portion interposed between the base portions. According to this configuration, the base portions of the busbars adjacent to each other are prevented from being short-circuited. 
     In one preferred embodiment, a pair of guide grooves that respectively receive and guide a pair of tips in the right-left direction of the base portion of a corresponding one of the busbars in the front-rear direction are respectively formed at a pair of corner portions that join the pair of partition wall portions and one of the pair of wall portions together. 
     According to this configuration, when the busbar is incorporated from the front-insertion-recess-portion side, the pair of tips in the right-left direction of the base portion of the busbar are inserted and guided by the pair of guide grooves of the pair of partitioning walls, and therefore it is possible to easily assemble the relay connector. 
     One preferred embodiment of the present invention provides a busbar that is used in a relay connector, the busbar including a base portion that extends in a right-left direction, a plurality of rear tabs that extend rearwardly from the base portion in a front-rear direction, a plurality of extension portions each of which extends from the base portion to a same side in an up-down direction, and a plurality of front tabs each of which extends from an extension end of each of the extension portions to a front in the front-rear direction. Each of the rear tabs includes a rear held portion adjacent to the base portion and a rear male terminal portion. Each of the front tabs includes a front held portion adjacent to the extension end and a front male terminal portion. According to this configuration, it is possible to provide a busbar that is capable of being suitably used in the relay connector, and the relay connector is enabled to fulfill the effects mentioned above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an exploded perspective view of a relay connector and a female terminal of a preferred embodiment of the present invention. 
         FIG.  2 A  is a perspective view of a first busbar, and  FIG.  2 B  is a perspective view of a second busbar. 
         FIG.  3 A  is a perspective view of the relay connector, and  FIG.  3 B  is a perspective view of the relay connector seen from another angle. 
         FIG.  4    is a plan view of the relay connector. 
         FIG.  5    is a front view of the relay connector. 
         FIG.  6    is a side view of the relay connector. 
         FIG.  7    is a bottom view of the relay connector. 
         FIG.  8 A  is a cross-sectional view of the relay connector, which corresponds to a cross-sectional view along line VIIIA-VIIIA of  FIG.  4   .  FIG.  8 B  is a cross-sectional view of a housing corresponding to  FIG.  8 A . 
         FIG.  9 A  is a front enlarged view of a main portion of the relay connector, which corresponds to an enlarged view of a part of  FIG.  5   .  FIG.  9 B  is a front enlarged view of a main portion of the housing, which corresponds to  FIG.  9 A . 
         FIG.  10    is a plan view of the housing. 
         FIG.  11    is a rear view of the housing. 
         FIG.  12    is a perspective view of the relay connector when a retainer is used. 
         FIG.  13    is a perspective view of the retainer. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment in which the present invention is embodied will be hereinafter described with reference to the drawings. 
       FIG.  1    is an exploded perspective view of a relay connector and a female terminal of a preferred embodiment of the present invention. As shown in  FIG.  1   , the relay connector  1  is a relay connector that connects a plurality of front female terminals  91  that are fitted from the rear XB in the front-rear direction X (i.e., toward the front XF) and a plurality of rear female terminals  92  that are fitted from the front XF in the front-rear direction X (i.e., toward the rear XB) together. 
     The front female terminal  91  includes an angularly cylindrical main body portion  94  having a lance  93  and an electric-wire connection portion  95  to which an electric wire D 1  is connected. The rear female terminal  92  includes an angularly cylindrical main body portion  97  having a lance  96  and an electric-wire connection portion  98  to which an electric wire D 2  is connected. In the following description, the front-rear direction X, the right-left direction Y, and the up-down direction Z are described as three directions that perpendicularly intersect each other. 
     The relay connector  1  is composed of a housing  2  and a plurality of busbars  3  disposed so as to be arrayed in the right-left direction Y. 
     The busbar  3  will be first described with reference to  FIG.  1   ,  FIG.  2 A , and  FIG.  2 B . 
     As shown in  FIG.  1   , the busbar  3  includes an upper row busbar  3 U and a lower row busbar  3 L that are arrayed in upper and lower two rows. 
     The upper row busbar  3 U includes, for example, two kinds of upper row busbars  3 Ua (see  FIG.  2 A ) and  3 Ub (see  FIG.  2 B ) as a plurality of kinds of busbars that differ in specifications from each other. The lower row busbar  3 L includes, for example, two kinds of lower row busbars  3 La and  3 Lb as a plurality of kinds of busbars that differ in specifications from each other. The upper row busbar  3 Ua, the upper row busbar  3 Ub, the lower row busbar  3 La, and the lower row busbar  3 Lb are referred to simply as the busbar  3  if it is necessary to collectively represent these busbars. 
     In an example shown in  FIG.  1   , in the upper row busbar  3 Ua that is one of the upper row busbars  3 Ua and  3 Ub, for example, six busbars are arranged in the right-left direction Y from a left end position in the right-left direction Y. Additionally, in the other upper row busbar  3 Ub, for example, a single busbar is disposed at a right end position in the right-left direction Y. Likewise, in the lower row busbar  3 La that is one of the lower row busbars  3 La and  3 Lb, for example, six busbars are arranged in the right-left direction Y from a left end position in the right-left direction Y. Additionally, in the other lower row busbar  3 Lb, for example, a single busbar is disposed at a right end position in the right-left direction Y. 
     The upper row busbar  3 Ua and the lower row busbar  3 La are up-downwardly symmetrical in shape, and common members are used in a state of being mutually opposite in direction. Additionally, the other upper row busbar  3 Ub and the other lower row busbar  3 Lb are up-downwardly symmetrical in shape, and common members are used in a state of being mutually opposite in direction. 
     Therefore, in the following description, the upper row busbar  3 U ( 3 Ua,  3 Ub) is described, and a description of the lower row busbar  3 L ( 3 La,  3 Lb) is omitted. 
     As shown in  FIG.  2 A , the upper row busbar  3 Ua includes a base portion  4 , two rear tabs  5 , two extension portions  6 , and two front tabs  7 . 
     The base portion  4  is a rectangular plate-shaped portion extending in the right-left direction Y. The base portion  4  includes a rear end edge  4   a , a front end edge  4   b , and a pair of tips  4   c  in the right-left direction Y (see also  FIG.  9 A ). The two rear tabs  5  are away from each other in the right-left direction Y, and extend from the rear end edge  4   a  of the base portion  4  to the rear XB in parallel in the front-rear direction X. 
     Each of the rear tabs  5  is a segmental portion having an angulated cross section, and includes a base end portion  51 , a forward end portion  52 , a rear held portion  53 , and a rear male terminal portion  54 . The base end portion  51  is connected to the base portion  4 . The forward end portion  52  is formed in a tapered shape. The rear held portion  53  is a part adjacent to the rear end edge  4   a  of the base portion  4 , and is a part including the base end portion  51 . In detail, the rear held portion  53  includes the base end portion  51  and a press-fit projection  51   a  that protrudes from the base end portion  51  to both sides in the right-left direction Y. The rear male terminal portion  54  is a part, which is closer to the forward end portion  52  than to the rear held portion  53 , of the rear tab  5 , and is a part that is fitted and connected to the rear female terminal  92 . 
     Each of the extension portions  6  is a segmental portion extending from the front end edge  4   b  of the base portion  4  to the upper side ZU in the up-down direction Z. Each of the extension portions  6  includes a base end  61  that is connected to the base portion  4  and an extension end  62 . 
     Each of the front tabs  7  extends from the extension end  62  (i.e., the upper end) of a corresponding extension portion  6  to the front side XF in the front-rear direction X. Each of the front tabs  7  is a segmental portion having an angulated cross section, and includes a base end portion  71 , a forward end portion  72 , a front held portion  73 , and a front male terminal portion  74 . The base end portion  71  is connected to the extension end  62  of a corresponding extension portion  6 . The forward end portion  72  is formed in a tapered shape. 
     The front held portion  73  is a part that is adjacent to the front XF of the extension end  62  and that includes the base end portion  71 . In detail, the front held portion  73  includes the base end portion  71  and a pair of right-left-direction protruding portions  71   a  that protrude from the base end portion  71  to both sides in the right-left direction Y, and is formed in a cross shape. The front male terminal portion  74  is a part, which is closer to the forward end portion  72  than to the front held portion  73 , of the front tab  7 , and that is fitted and connected to the front female terminal  91 . 
     As shown in  FIG.  2 B , the other upper row busbar  3 Ub includes the base portion  4 , three rear tabs  5 , three extension portions  6 , and three front tabs  7 . The other upper row busbar  3 Ub is configured to be larger by one in the number of the rear tabs  5 , in the number of the extension portions  6 , and in the number of the front tabs  7  than the upper row busbar  3 Ua. 
     Next, the housing  2  will be described. 
       FIG.  3 A  is a perspective view of the relay connector  1 , and  FIG.  3 B  is a perspective view of the relay connector  1  seen from another angle than  FIG.  3 A .  FIG.  4    is a plan view of the relay connector  1 .  FIG.  5    is a front view of the relay connector  1 .  FIG.  6    is a side view of the relay connector  1 .  FIG.  7    is a bottom view of the relay connector  1 .  FIG.  8 A  is a cross-sectional view of the relay connector  1 , which corresponds to a cross-sectional view along line VIIIA-VIIIA of  FIG.  4   .  FIG.  8 B  is a cross sectional view of the housing  2  corresponding to  FIG.  8 A .  FIG.  9 A  is a front enlarged view of a main portion of the relay connector  1 , which corresponds to an enlarged view of a part of  FIG.  5   .  FIG.  9 B  is a front enlarged view of a main portion of the housing  2 , which corresponds to  FIG.  9 A .  FIG.  10    is a plan view of the housing  2 .  FIG.  11    is a rear view of the housing  2 . 
     Referring to  FIG.  3 A ,  FIG.  3 B , and  FIG.  4    to  FIG.  7   , the housing  2  includes a ceiling wall portion  11 , a bottom wall portion  12 , a front wall portion  13 , rear wall portion  14 , a pair of sidewall portions  15 , a front-rear-direction intermediate wall portion  16  (see  FIG.  8 A  and  FIG.  8 B ), and an up-down-direction intermediate wall portion  17  (see  FIG.  8 A  and  FIG.  8 B ). The housing  2  additionally includes a partition wall portion  18  (see  FIG.  9 A  and  FIG.  9 B ), a partially-dividing wall portion  19  (see  FIG.  9 A  and  FIG.  9 B ), a plurality of front busbar-housing portions F, a plurality of rear busbar-housing portions B, and a plurality of busbar holding portions H. The housing  2  is integrally molded by an insulating synthetic resin material. The front busbar-housing portion F is a collective term for an upper-row front busbar-housing portion FU and lower-row front busbar-housing portion FL described later. The rear busbar-housing portion B is a collective term for an upper-row rear busbar-housing on BU and a lower-row rear busbar-housing portion BL described later. 
     The ceiling wall portion  11  includes a front portion  11   a , a rear portion  11   b , an intermediate protruding portion  11   c , a front locking hole  11   d , and a rear locking hole  11   e . The bottom wall portion  12  includes a front portion  12   a , a rear portion  12   b , an intermediate protruding portion  12   c , a front locking hole  12   d , and a rear locking hole  12   e . The sidewall portion  15  includes a front portion  15   a , a rear portion  15   b , an intermediate protruding portion  15   c , a front extension protruding portion  15   d , a rear extension protruding portion  15   e , a pair of locking projections  15   f , and a pair of locking projections  15   g.    
     The intermediate protruding portion  11   c  of the ceiling wall portion  11 , the intermediate protruding portion  12   c  of the bottom wall portion  12 , and the intermediate protruding portion  15   c  of the sidewall portion  15  are annularly continuous with each other. The lance  93  of the front female terminal  91  and the lance  96  of the rear female terminal  92  (see  FIG.  1   ) are locked into each of the front locking holes  11   d  and  12   d  and each of the rear locking holes  11   e  and  12   e , respectively. 
     The front busbar-housing portion F, the rear busbar-housing portion B, and the busbar holding portion H are each disposed so as to be the same in number as the busbar  3 . 
     A plurality of front busbar-housing portions F are arrayed in the right-left direction Y, and the busbar  3  corresponding to each of the front busbar-housing portions F is disposed in a state of having been inserted therein from the front XF. Each of the front busbar-housing portions F houses the front portion (the front male terminal portion  74  of the front tab  7 ) of the busbar  3  corresponding thereto. Each of the rear busbar-housing portions B houses the rear portion (the rear male terminal portion  54  of the rear tab  5 ) of the busbar  3  corresponding thereto. Each of the busbar holding portions H holds the intermediate portion (the rear held portion  53 , the base portion  4 , and the front held portion  73 ) in the front-rear direction X of the busbar  3  corresponding thereto. 
     The front busbar-housing portion F is configured such that a plurality of housing portions F are arranged in the right-left direction Y so as to form a row and such that two lines of housing portions F (i.e., two lines consisting of the upper-row front busbar-housing portion FL) and the lower-row front busbar-housing portion FL) are arranged in the up-down direction Z. The upper-row front busbar-housing portion FU and the lower-row front busbar-housing portion FL are referred to simply as the front busbar-housing portion F if it is necessary to collectively represent these busbar-housing portions. 
     The upper-row front busbar-housing portion EU includes one upper-row front busbar-housing portion FUa, which houses the front portion of one upper row busbar  3 Ua, and the other upper-row front busbar-housing portion FUb, which houses the front portion of the other upper row busbar  3 Ub. 
     The lower-row front busbar-housing portion FL includes one lower-row front busbar-housing portion FLa, which houses the front portion of the lower row busbar  3 La, and the other lower-row front busbar-housing portion FLb, which houses the front portion of the other lower row busbar  3 Lb. 
     As shown in  FIG.  5    and  FIG.  10   , each of the front busbar-housing portions F contains a plurality of front insertion recess portions SF. Each of the front insertion recess portions SF is open in the front wall portion  13 . The front insertion recess portion SF is configured such that a plurality of insertion recess portions SF are arranged in the right-left direction Y so as to form a row and such that two lines of insertion recess portions SF (i.e., two lines consisting of an upper-row front insertion recess portion SFU and a lower-row front insertion recess portion SFL) are arranged in the up-down direction Z. The upper-row front insertion recess portion SFU and the lower-row front insertion recess portion SFL are formed so as to be up-downwardly symmetrical with respect to the up-down-direction intermediate wall portion  17  extending in the right-left direction Y when seen from the front. The upper-row front insertion recess portion SFU and the lower-row front insertion recess portion SFL are referred to simply as the front insertion recess portion SF if it is necessary to collectively represent these front insertion recess portions. 
     As shown in  FIG.  11   , the rear busbar-housing portion B is configured such that a plurality of busbar-housing portions B are arranged in the right-left direction Y so as to form a row and such that two lines of busbar-housing portions B (i.e., two lines consisting of the upper-row rear busbar-housing portion BU and the lower-row rear busbar-housing portion FL) are arranged in the up-down direction Z. The upper-row rear busbar-housing portion BU and the lower-row rear busbar-housing portion BL are referred to simply as the rear busbar-housing portion B if it is necessary to collectively represent these busbar-housing portions. 
     The upper-row rear busbar-housing portion BU includes one upper-row rear busbar-housing portion BUa, which houses the rear portion of the upper row busbar  3 Ua, and the other upper-row rear busbar-housing portion BUb, which houses the rear portion of the other upper row busbar  3 Ub. 
     The lower-row rear busbar-housing portion BL includes one lower-row rear busbar-housing portion BLa, which houses the rear portion of the lower row busbar  3 La, and the other lower-row rear busbar-housing portion BLb, which houses the rear portion of the other lower row busbar  3 Lb. 
     The rear busbar-housing portion B contains a plurality of rear insertion recess portions SB. The rear insertion recess portion SB is open in the rear wall portion  14 . The rear insertion recess portion SB is configured such that a plurality of insertion recess portions SB are arranged in the right-left direction Y so as to form a row and such that two lines of insertion recess portions SB (i.e., two lines consisting of an upper-row rear insertion recess portion SBU and a lower-row rear insertion recess portion SBL) are arranged in the up-down direction Z. The upper-row rear insertion recess portion SBU and the lower-row rear insertion recess portion SBL are formed so as to be up-downwardly symmetrical with respect to the up-down-direction intermediate wall portion  17  extending in the right-left direction Y when seen from the rear. The upper-row rear insertion recess portion SBU and the lower-row rear insertion recess portion SBL are referred to simply as the rear insertion recess portion SB if it is necessary to collectively represent these insertion recess portions. 
     The upper-row front busbar-housing portion FUa and the lower-row front busbar-housing portion FLa are up-downwardly symmetrical, and therefore the upper-row front busbar-housing portion FUa is chiefly described in the following description. 
     As shown in  FIG.  9 A  and  FIG.  9 B , each of the upper-row front busbar-housing portions FUa is defined by the pair of partition wall portions  18  and  18  that face each other in the right-left direction Y, by the ceiling wall portion  11  and the up-down-direction intermediate wall portion  17  both of which serve as a pair of wall portions that face each other in the up-down direction, and by a front wall surface  16   a  of the front-rear-direction intermediate wall portion  16 . The partially-dividing wall portion  19  that extends from the ceiling wall portion  11  toward the up-down-direction intermediate wall portion  17 , which is on the down side ZL, is disposed between the pair of partition wall portions  18  and  18 . As shown in  FIG.  5   , some partition wall portions  18  are formed integrally with inner sides of the right and left sidewall portions  15 . 
     As shown in  FIG.  5   , the busbars  3 U housed in the upper-row front busbar-housing portions FU adjacent in the right-left direction Y (In detail, the base portions  4  with reference to  FIG.  2 A . In more detail, the tips  4   c  of the base portions  4 ) are insulated from each other with the partition wall portion  18  interposed therebetween. 
     As shown in  FIG.  9 A  and  FIG.  9 B , the upper-row front insertion recess portion SFU is disposed between the partially-dividing wall portion  19  and each of the partition wall portions  18 . The two upper-row front insertion recess portions SFU are partially divided by the partial-dividing wall portion  19  in the right-left direction Y. The lower portions of the two upper-row front insertion recess portions SFU are communicated with each other. Corresponding front male terminal portions  74  of the upper row busbar  3 Ua are housed and disposed in the two upper-row front insertion recess portions SFU, respectively. 
     Each of the partition wall portions  18  has a protruding portion  18   a  and a protruding portion  18   b  that protrude to both sides in the right-left direction Y at a position closer to the up-down-direction intermediate wall portion  17 . Additionally, the partially-dividing wall portion  19  has a protruding portion  19   a  and a protruding portion  19   b  that protrude to both sides in the right-left direction Y in its lower end portion. 
     A pair of guide grooves  30  are formed at a pair of corner portions C that join the pair of partition wall portions  18  and the up-down-direction intermediate wall portion  17  together. The pair of guide grooves  30  receive and guide the pair of tips  4   c  in the right-left direction Y of the base portions  4  of corresponding busbars  3 , respectively, in the front-rear direction X (in the direction perpendicular to the plane of paper in  FIG.  9 A ). One of the pair of guide grooves  30  is defined between the protruding portion  18   b  of one of the pair of partition wall portion  18  and the up-down-direction intermediate wall portion  17 , and the other one of the pair of guide grooves  30  is defined between the protruding portion  18   a  of the other one of the pair of partition wall portions  18  and the up-down-direction intermediate wall portion  17 . 
     The busbar holding portion H includes a press-fit hole  31  that serves as a first holding portion, a second holding groove  32  that serves as a second holding portion, and a third holding groove  33  that serves as a third holding portion. 
     The press-fit hole  31  serving as the first holding portion passes through the front-rear-direction intermediate wall portion  16  in the front-rear direction. The rear held portion  53  is pressed and fixed in the press-fit hole  31 . 
     The second holding groove  32  is formed a the front wall surface  16   a  of the front-rear-direction intermediate wall portion  16 , and extends in the right-left direction Y. The second holding groove  32  is a through-groove that passes through the front-rear-direction intermediate wall portion  16  in the front-rear direction. The second holding groove  32  holds the front held portion  73  fitted therein. The second holding groove  32  includes a pair of inner wall surfaces  32   a  that face each other in the up-down direction Z. The pair of inner wall surfaces  32   a  of the second holding groove  32  position and hold the front held portion  73  in the up-down direction Z. 
     The third holding groove  33  is formed at the front wall surface  16   a  of the front-rear-direction intermediate wall portion  16 , and extends in the up-down direction Z. The third holding groove  33  extends in the up-down direction Z from a central portion in the right-left direction Y of the second holding groove  32  to the up-down-direction intermediate wall portion  17 . The shape of the capital letter T is formed by the second holding groove  32  and the third holding groove  33 . The third holding groove  33  is disposed between the protruding portion  18   b  of one of the partition wall portions  18  and the protruding portion  19   a  of the partially-dividing wall portion  19 . Additionally, the third holding groove  33  is disposed between the protruding portion  18   a  of the other one of the partition wall portions  18  and the protruding portion  19   b  of the partially-dividing wall portion  19 . 
     The third holding groove  33  holds the extension portion  6  fitted to the third holding groove  33 . The third holding groove  33  includes a grooved bottom surface  33   a  and a pair of inner wall surfaces  33   b  that face each other in the right-left direction Y. The grooved bottom surface  33   a  functions as an abutting portion against which the extension portion  6  is abutted from the front, and positions the busbar  3  in the front-rear direction X by use of the extension portion  6 . The pair of inner wall surfaces  33   b  positions and holds the extension portion  6  in the right-left direction Y. 
     In the present preferred embodiment, the following operational effects are fulfilled. 
     In detail, the busbar holding portion H of the housing  2  includes a first holding portion (press-fit hole  31 ), a second holding portion (second holding groove  32 ), and a third holding portion (third holding groove  33 ) as shown in  FIG.  8 A ,  FIG.  8 B ,  FIG.  9 A , and  FIG.  9 B . In the busbar  3 , the rear held portion  53  of the rear tab  5  held by the first holding portion (press-fit hole  31 ), the front held portion  73  of the front tab  7  held by the second holding portion (second holding groove  32 ), and the extension portion  6  held by the third holding portion (third holding groove  33 ) are disposed in a crank shape (see also  FIG.  2 A ), and their crank-shaped portions are connected together through the base portion  4 . Therefore, it is possible to realize a relay connector  1  having a high holding force by which the busbar  3  is held even if the relay connector  1  is small in size. 
     Additionally, the rear held portion  53  of the rear tab  5  is pressed and fixed to the press-fit hole  31  serving as the first holding portion, and therefore the busbar  3  is firmly fixed particularly in the front-rear direction Z. 
     Additionally, the front held portion  73  of the front tab  7  is fitted and held by the second holding groove  32  serving as the second holding portion disposed at the front wall surface  16   a  (i.e., wall surface on the front-insertion-recess-portion-SF side) in the front-rear-direction intermediate wall portion  16 . The front held portion  73  is positioned and held by the pair of inner wall surfaces  32   a  of the second holding groove  32  in the up-down direction Z. Hence, the busbar  3  is positioned and held in the up-down direction Z by use of the front held portion  73 . 
     When seen in the up-down direction Z, the front held portion  73  is formed in a cross shape including the pair of right-left-direction protruding portions  71   a  that protrude to both sides in the right-left direction Y (see  FIG.  2 A ). Therefore, the busbar  3  is firmly positioned and held in the up-down direction Z by use of the front held portion  73  assuming the cross shape. 
     Additionally, the extension portion  6  of the busbar  3  is abutted against an abutting portion (the grooved bottom surface  33   a  of the third holding groove  33 ) disposed at the front wall surface  16   a  of the front-rear-direction intermediate wall portion  16  as shown in  FIG.  8 A ,  FIG.  8 B ,  FIG.  9 A , and  FIG.  9 B . Therefore, it is possible to highly accurately position and hold the busbar  3  in the front-rear direction X by use of the extension portion  6 . 
     Additionally, the extension portion  6  of the busbar  3  is fitted and held by the third holding groove  33  serving as the third holding portion disposed at the front wall surface  16   a  of the front-rear-direction intermediate wall portion  16 . The extension portion  6  is positioned and held by the pair of inner wall surfaces  33   b  of the third holding groove  33  in the right-left direction Y, and the extension portion  6  is positioned and held by the grooved bottom surface  33   a  (abutting portion) of the third holding groove  33  in the front-rear direction X. Hence, the busbar  3  is positioned and held in the front-rear direction X and in the right-left direction Y by use of the extension portion  6 . 
     Additionally, the front busbar-housing portion F into which the busbar  3  is inserted and disposed from the front XF is defined by the pair of partition wall portions  18  that face each other in the right-left direction Y and by the ceiling wall portion  11  and the up-down-direction intermediate wall portion  17  (the bottom wall portion  12  and the up-down-direction intermediate wall portion  17 ) that face each other in the up-down direction Z. The base portions  4  of the busbars  3  housed in the front busbar-housing portions F adjacent in the right-left direction Y are insulated from each other with the partition wall portion  18  interposed therebetween. Therefore, the base portions  4  of the busbars adjacent to each other are prevented from being short-circuited. 
     Additionally, the pair of guide grooves  30  into which the pair of tips  4   c  in the right-left direction Y of the base portion  4  of the busbar  3  are respectively inserted and guided in the front-rear direction X are formed at the pair of corner portions C that join the pair of partition wall portions  18  and, for example, the up-down-direction intermediate wall portion  17  together. 
     Therefore, when the busbar  3  is incorporated from the front-insertion-recess-portion-SF side, the pair of tips  4   c  in the right left direction Y of the base portion  4  of the busbar  3  are inserted and guided by the pair of guide grooves  30 , and therefore it is possible to easily assemble the relay connector  1 . 
     Additionally, according to the busbar  3 , it is possible to provide a busbar that is capable of being suitably used in the relay connector  1 , and the relay connector  1  is enabled to fulfill the operational effects mentioned above. 
     Additionally, each of the female terminals (see  FIG.  1   ) may be retained by use of a retainer  8  as shown in  FIG.  12   . The retainer  8  includes a first wall portion  81 , a pair of second wall portions  82 , a third wall portion  83 , and a pair of elastic hooks  84  as shown in  FIG.  13   . The first wall portion  81  covers the front and rear portions  11   a  and  11   b  of the ceiling wall portion  11  and the front and rear portions  12   a  and  12   b  of the bottom wall portion  12  (see  FIG.  8 A ), respectively. Additionally, the pair of second wall portions  82  cover a corresponding part of each of the sidewall portions  15 . The third wall portion  83  is locked by the main body portions  94  and  97  of corresponding female terminals (see  FIG.  1   ). The elastic hooks  84  are elastically surmounted and locked by corresponding locking projections  15   f  and  15   g.    
     The present invention is not limited to the preferred embodiment, and at least one of the upper and lower row busbars  3 U and  3 L may be configured by a single-specification busbar. 
     Although the present invention has been described in detail from the concrete aspects, those skilled in the art who have understood the aforementioned contents will easily recognize its modifications, variations, and equivalents. Therefore, the present invention should be within the scope of the claims and the scope of its equivalents. 
     REFERENCE SIGNS LIST 
     
         
           1  relay connector 
           2  housing 
           3  busbar 
           4  base portion 
           4   c  tip 
           5  rear tab 
           6  extension portion 
           7  front tab 
           11  ceiling wall portion 
           12  bottom wall portion 
           16  front-rear-direction intermediate wall portion 
           16   a  front wall surface 
           17  up-down-direction intermediate wall portion 
           18  partition wall portion 
           18   a ,  18   b  protruding portion 
           19  partially-dividing wall portion 
           19   a ,  19   b  protruding portion 
           30  guide groove 
           31  press-fit hole (first holding portion) 
           32  second holding groove (second holding portion) 
           32   a  inner wall surface 
           33  third holding groove (third holding portion) 
           33   a  grooved bottom surface (abutting portion) 
           33   b  inner wall surface 
           53  rear held portion 
           54  rear male terminal portion 
           62  extension end 
           71  base end portion 
           71   a  right-left-direction protruding portion 
           73  front held portion 
           74  front male terminal portion 
           91  front female terminal 
           92  rear female terminal 
         B rear busbar-housing portion 
         BLa, BLb (BL) lower-row rear busbar-housing portion 
         BUa, BUb (BU) upper-row rear busbar-housing portion 
         C corner portion 
         F front busbar-housing portion 
         FLa, FLb (FL) lower-row front busbar-housing portion 
         FUa, FUb (FU) upper-row front busbar-housing portion 
         H busbar holding portion 
         SB rear insertion recess portion 
         SBL lower-row rear insertion recess portion 
         SBU upper-row rear insertion recess portion 
         SF front insertion recess portion 
         SFL lower-row front insertion recess portion 
         SFU upper-row front insertion recess portion 
         X front-rear direction 
         XB rear side 
         XF front side 
         Y right-left direction 
         Z up-down direction 
         ZU upward side 
         ZL downward side