Patent Publication Number: US-10326227-B2

Title: Terminal fitting and connector

Description:
BACKGROUND 
     Field of the Invention 
     The invention relates to a terminal fitting and a connector. 
     Related Art 
     Japanese Unexamined Patent Publication No. 2001-332335 discloses a terminal fitting that is locked doubly in a cavity of a connector housing by a locking lance and a retainer. The terminal fitting includes a rectangular tubular terminal connecting portion to be connected to a mating terminal fitting. A rear end of the terminal connecting portion has an upright surface that is to be locked by a similarly upright surface on the retainer. 
     The above-described structures for locking the surfaces that are perpendicular to a withdrawing direction of the terminal fitting generally present no particular practical problem in producing a sufficient terminal holding force. However, if a connector is reduced in size and a terminal fitting also is thinned and reduced in size, a terminal holding force may not be sufficient if the above-described locking structure is still adopted. 
     Further, a strong pulling force on the terminal fitting may displace the retainer and release locking if the engagement margin between the upright locking surfaces is small. 
     The invention was completed on the basis of the above situation and aims to provide a terminal fitting capable of improving a terminal holding force by a simple configuration and a connector accommodating the terminal fitting. 
     SUMMARY 
     The invention is directed to a terminal fitting to be inserted into a connector housing from behind and retained and held in the connector housing by being locked by a retainer mounted into the connector housing. The terminal fitting includes a terminal connecting portion connectable to a mating terminal fitting. A wire connecting portion is disposed behind the terminal connecting portion and is configured to be connected to an end part of a wire. A retainer locking portion projects on the terminal connecting portion and has a retainer locking surface to be locked by the retainer. The retainer locking surface is formed into a reverse tapered shape from a projecting end toward a base end. 
     The present invention also is directed to a connector that has the above terminal fitting accommodated in the connector housing. 
     According to the invention, the retainer locking surface of the terminal fitting is formed into the reverse tapered shape. Thus, a pulling force on the terminal fitting in a withdrawing direction causes the retainer locking portion to bite into the retainer and lock more strongly. In this way, a terminal holding force can be improved. Further, even if an engagement margin between the retainer and the terminal fitting is small, the biting part is caught to prevent the terminal fitting from being unlocked. 
     The retainer locking portion may have a substantially U shape composed of a standing piece rising out from an outer surface of the terminal connecting portion and a folded piece folded from a rising end part of the standing piece toward the outer surface of the terminal connecting portion. Rear end surfaces of the standing piece and the folded piece are substantially flush with each other to form the retainer locking surface. A remaining part of the terminal fitting excluding the retainer locking surface has a plated surface with a plating layer laminated thereon, but the retainer locking surface is a non-plated surface having no plating layer. 
     In the process of manufacturing the terminal fitting, a base material first is stamped into a predetermined development shape. Subsequently, plating is applied to both sides of a stamped piece in a state of development and, thereafter, the plated piece is folded into a predetermined shape to assemble the terminal fitting. At this time, if the retainer locking portion is folded into a U shape, the retainer locking surface is also U-shaped as a matter of course. A region on a rising side and a region on a folded side of the U-shaped part both desirably are brought into contact with the retainer. However, there has been a possibility that the region on the rising side and the region on the folded side do not constitute the same surface due to a variation during bending and only one region may contact the retainer, with the result that a terminal holding force is reduced. 
     Accordingly, in the present invention, post-processing, such as cutting, is applied after the retainer locking surface is processed to be folded. Thus, the retainer locking surface becomes a non-plated surface, and the region on the rising side and the region of the folded side constitute the same surface and both regions contact the retainer. Thus, a predetermined terminal holding force can be obtained reliably. 
     Further, a lance locking portion may project on a side of the terminal connecting portion before the retainer locking portion. The lance locking portion may have a lance locking surface lockable by a deflectable locking lance formed in the connector housing. Additionally, the lance locking surface may be formed into a reverse tapered shape from a projecting end side toward a base end side. According to this configuration, since the lance locking surface can also bite into the locking lance, the terminal holding force can be improved further. 
     A specific embodiment of the invention is described with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of a connector housing. 
         FIG. 2  is a bottom view of the connector housing. 
         FIG. 3  is a front view of a retainer. 
         FIG. 4  is a side view of a terminal fitting. 
         FIG. 5  is a plan view of the terminal fitting. 
         FIG. 6  is a front view of the terminal fitting. 
         FIG. 7  is a section along A-A of  FIG. 6 . 
         FIG. 8  is an enlarged section of a retainer locking portion. 
         FIG. 9  is a side view in section showing a state where the terminal fitting is doubly retained by the retainer and a locking lance in the connector housing. 
     
    
    
     A specific embodiment of the invention is described with reference to the drawings. 
     (Connector Housing  1 ) 
     The connector housing  1  shown in  FIG. 1  is made of synthetic resin and has cavities  2  for accommodating terminal fittings T formed in each of three stages inside the connector housing  1 . Each cavity  2  is formed along a front-rear direction and the terminal fitting T is insertable into each cavity  2  from behind. 
     A locking lance  3  for primarily locking the terminal fitting T is disposed at a position near a front end part inside each cavity  2 . The locking lance  3  is cantilevered obliquely forward from a bottom surface of the cavity  2  and is deflectable in a vertical direction as shown (direction perpendicular to an inserting direction of the terminal fitting T). A front end surface  3 A of the locking lance  3  is inclined when the locking lance  3  is in a natural state. Specifically, this inclined surface is formed with such an inclination that an end edge on the side of the cavity  2  is located on a front side in the inserting direction, and an opposite end edge is located on a rear side in the inserting direction. 
     A deflectable lock arm  4  for locking a mating connector in a connected state is provided on the upper surface of the connector housing  1 . On the other hand, as shown in  FIG. 2 , a retainer insertion hole  6  is open in a lower surface of the connector housing  1  and a retainer  5  can be inserted therein. The retainer insertion hole  6  is formed along a width direction of the connector housing  1  and divides all of the cavities  2  into front and rear sections behind the locking lances  3 , as shown in  FIG. 9 . Further, opposite end parts of the retainer insertion hole  6  in the width direction serve as lock receiving portions  8 . The lock receiving portions  8  are locked to retain the retainer  5  when locking legs  7  of the retainer  5  are inserted. 
     As shown in  FIG. 9 , a front holder  9  is mounted on a front surface of the connector housing  1 . The front holder  9  is provided with accommodation recesses  10  communicating with the respective cavities  2  and configured to accommodate front end parts of the terminal fittings T. A front wall of the accommodation recess  10  stops the terminal fitting T in front and a tab insertion hole  11  is formed in the front wall to receive a tab of a mating terminal fitting. 
     (Terminal Fitting T) 
     The terminal fitting T is made of a thin conductive metal plate material as a base material. The base material is stamped into a predetermined development shape, and tin plating (or nickel plating) is applied to both sides of the stamped piece. The terminal fitting T in a development state after a plating process then is folded into the following form. 
     As shown in  FIG. 4 , the terminal fitting T is composed of a terminal connecting portion  12  for connection to the mating terminal fitting and a wire connecting portion  13  for connection to a wire. 
     The terminal connecting portion  12  is substantially in the form of a rectangular tube open both forward and rearward. As shown in  FIG. 6 , the terminal connecting portion  12  includes a bottom wall  14  flush with that of the wire connecting portion  13  and side walls  15 R,  15 L rising from both widthwise sides of the bottom wall  14 . A ceiling wall  16  extends horizontally from a rising end of one side wall  15 L (left side wall in  FIG. 6 ) toward the other side wall  15 R (right side wall in  FIG. 6 ). 
     As shown in  FIGS. 4, 5 and 7 , two projecting parts are provided separately on front and rear sides of a rising end edge of the right side wall  15 R. The front part is a lance locking portion  17  to be locked by the locking lance  3  and the rear part is a retainer locking portion  18  to be locked by the retainer  5 . 
     The retainer locking portion  18  projects from the rising end edge of the right side wall  15 R while being formed into a substantially U shape in a back view. Specifically, the retainer locking portion  18  is formed with a standing piece  19  flush with and rising from the right side wall  15 R, and a folded piece  20  extending substantially horizontally inward from a rising end of the standing piece  19  and folded toward the ceiling wall  16  from an extending end. 
     Rear end surfaces of the standing piece  19  and the folded piece  20  serve as a retainer locking surface  22  to be locked by the retainer  5 . As shown in  FIGS. 4, 7 and 8 , the retainer locking surface  22  is formed into a reverse tapered shape, i.e. formed into an inclined surface inclined forward in the inserting direction of the terminal fitting T from an outer end to a base end of the retainer locking portion  18 . In other words, the retainer locking portion  18  is formed such that a length of a base side in the front-rear direction is longer than that of a tip side in the front-rear direction. In this embodiment, the retainer locking surface  22  is inclined continuously to a position including a rear end surface of the ceiling wall  16 . Thus, a region of the terminal fitting T lockable by the retainer  5  is a range from the retainer locking surface  22  to the rear end surface of the ceiling wall  16 . 
     The retainer locking surface  22  is formed by post-processing such as cutting after the terminal fitting T is assembled. By this cutting process, the retainer locking surface  22  is formed so that the rear end surfaces of the standing piece  19  and the folded piece  20  are coplanar. As a result, the retainer locking surface  22  is a non-plated surface by having a plating layer  34  scraped off, as shown in  FIG. 8 . 
     The lance locking portion  17  is provided on a front part of the terminal connecting portion  12 . Similar to the retainer locking portion  18 , the lance locking portion  17  also is folded into a U shape. Specifically, the lance locking portion  17  includes a rising piece  23  standing from the rising end edge of the right side wall  15 R and a hanging piece  24  folded toward the ceiling wall  16  after extending horizontally in from an end edge of the rising piece  23 . 
     A rear end surface of the lance locking portion  17  serves as a lance locking surface  26  to be locked by the locking lance  3 . A slightly vertical part is formed on a projecting end part of this lance locking surface  26 , and a height range from a lower end of the vertical part to the ceiling wall is processed into a reverse tapered shape, similar to the retainer locking portion  18 . A gradient of the lance locking surface  26  is substantially equal to that of the front end surface of the locking lance  3  in a state where the locking lance  3  locks the terminal fitting T (substantially natural state). Further, an angle of inclination of the lance locking surface  26  to the vertical direction is larger than that of the retainer locking surface  22  to the vertical direction. 
     Similar to the retainer locking surface  22 , the lance locking surface  26  also is formed by post-processing such as cutting after the terminal connecting portion  12  is assembled. Thus, the lance locking surface  26  is also a non-plated surface by having the plating layer  34  scraped off. 
     A resilient tongue  27  is provided inside the terminal connecting portion  12  and can establish electrical conduction by resiliently contacting the mating terminal fitting. 
     The wire connecting portion  13  is composed of a wire barrel  28  to be crimped to a core part of a wire W and an insulation barrel  29  disposed behind the wire barrel  28  and to be crimped to a coating part of the wire W. 
     (Retainer  5 ) 
     The retainer  5  is made of synthetic resin and includes a body  30  formed into a block. The retainer  5  is insertable into the retainer insertion hole  6  of the connector housing  1 . As shown in  FIG. 3 , the two locking legs  7  are formed on opposite widthwise side edge parts of a front side (upper side in  FIG. 3 ) of the retainer  5  in the inserting direction. A lock claw  31  is formed on a tip of each locking leg  7  and is deflectable in the width direction. Although not shown in detail, when the retainer  5  is inserted into the retainer insertion hole  6 , the lock claw  31  locks at two positions in each lock receiving portion  8  of the connector housing  1  and the retainer  5  is held at each position. One position is a partial locking position where a mounting depth of the retainer  5  is shallow and the terminal fittings T freely can be inserted into and withdrawn from the cavities  2  at this position. The other position is a full locking position where the mounting depth of the retainer  5  is deep. The retainer  5  can lock the terminal fittings T at this position to doubly retain the terminal fittings T together with the locking lances  3 . 
     As shown in  FIG. 3 , window holes  32  are open in two stages in a height direction in the body  30  of the retainer  5  so that the entire body  30  is formed into a lattice. When the retainer  5  is at the partial locking position, the window holes  32  can be aligned with and communicate with the respective cavities  2  in the corresponding stages (two stages located on a rear side in the inserting direction of the retainer  5 ) in the connector housing  1 . 
     As shown in  FIGS. 3 and 9 , locking projecting edges  33  are formed integrally to project along the width direction on parts of opening edges of the respective window holes  32  located on rear sides in the inserting direction of the retainer  5  and on a front edge part of the body  30  in the inserting direction. Each locking projecting edge  33  is locked to the retainer locking surface  22  when the retainer  5  is at the full locking position shown in  FIG. 9 . As shown in  FIG. 9 , a front surface of each locking projecting edge  33  is a vertically upright surface in this embodiment. 
     When the retainer  5  is at the partial locking position, each locking projecting edge  33  is retracted outside an insertion path for the terminal fitting T to allow the insertion and withdrawal of the terminal fitting T. However, when the retainer  5  is moved to the full locking position, each locking projecting edge  33  projects into the insertion path for the terminal fitting T to face and lock the retainer locking surface  22 . 
     Next, functions and effects of this embodiment configured as described above are described. With the retainer  5  held at the partial locking position, the terminal fittings T are inserted respectively into each cavity  2  from behind. While the terminal fitting T is moving forward in the cavity  2 , the retainer locking portion  18  rides on the locking lance  3  to deflect the locking lance  3 . The locking lance  3  resiliently returns to the substantially natural state when the terminal fitting T reaches a proper position to lock the lance locking portion  17  of the terminal fitting T. The lance locking surface  26  is formed into the reverse tapered shape. Thus, even if the wire is pulled in the primarily locked state, the terminal fitting T is caught to bite into the locking lance  3 . Thus, the terminal fitting T is retained with a sufficient holding force in the primarily locked state. In addition, the gradients of the front end surface of the locking lance  3  and the lance locking surface  26  are substantially equal. Thus, these surfaces are locked to each other while being held in surface contact. This also contributes to an improvement of the terminal holding force in the primarily locked state. 
     When the terminal fittings T are inserted to the proper position into all the cavities  2  in this way, the retainer locking surfaces  22  are facing the retainer insertion hole  6  with almost no clearance defined therebetween. Subsequently, a pushing force is applied to the retainer  5  to move the retainer  5  from the partial locking position to the full locking position. When the retainer  5  reaches the full locking position, each locking projecting edge  33  of the retainer  5  locks the retainer locking surface  22  of the retainer locking portion  18  (secondarily locked state). 
     The retainer locking surface  22  is formed into the reverse tapered shape. Thus, if a pulling force is applied to the terminal fitting T, a tip part of the retainer locking surface  22  bites into the locking projecting edge  33 . Thus, a high locking force is obtained. Even if an engagement margin of the locking projecting edge  33  with the retainer locking surface  22  is small, it is possible to avoid a situation where the locking projecting edge  33  is displaced from the retainer locking surface  22  and maintain the locked state by an effect of the reverse taper. 
     In addition, the retainer locking surface  22  is formed by cutting or the like after the terminal connecting portion  12  including the retainer locking portion  18  is bent. As described above, if the retainer locking surface  22  is formed in advance before bending, the rear end surfaces of the standing piece  19  and the folded piece  20  may be displaced in the front-rear direction without being coplanar during bending. However, by post-processing the retainer locking surface  22 , as in this embodiment, the rear end surfaces of the standing piece  19  and the folded piece  20  reliably are made flush with each other. Thus, the rear end surfaces of the standing piece  19  and the folded piece  20  can be brought into contact with the locking projecting edge  33 , and a wide locking area can be ensured as compared to the case where either one of these rear end surfaces is brought into contact, thereby contributing to an improvement of the locking force by the retainer  5 . Note that this function is similarly exhibited also on the lance locking surface  26 . 
     As just described, the locking force of the locking lance  3  to lock the terminal fitting T and the locking force by the retainer  5  both are increased in this embodiment. Thus, the terminal holding force can be improved drastically. 
     The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments also are included in the scope of the invention. 
     Although the lance locking surface  26  is also formed into the reverse tapered shape in addition to the retainer locking surface  22  in the above embodiment, the lance locking surface  26  may be a vertically upright surface as before. 
     Although the lance locking portion  17  projects on the terminal fitting T to enable locking by the locking lance  3  in the above embodiment, a locking hole may be open in the terminal connecting portion  12  instead of the lance locking portion  17  and the locking lance  3  may be locked to this locking hole. 
     Although the retainer locking portion and the lance locking portion are both folded into a U shape to have a two-plate structure in the above embodiment, each of these locking portions may be formed by a single plate instead of the folding structure. 
     Although the present invention is applied to the female terminal fitting in the above embodiment, application to a male terminal fitting is also possible. In this case, the male terminal fitting includes a tab, a rectangular tube connected behind the tab and a wire connecting portion connected behind the rectangular tube. In the male terminal fitting, the terminal connecting portion of the present invention is defined by the tab and the rectangular tube. 
     LIST OF REFERENCE SIGNS 
     
         
           1  . . . connector housing 
           3  . . . locking lance 
           5  . . . retainer 
           12  . . . terminal connecting portion 
           13  . . . wire connecting portion 
           17  . . . lance locking portion 
           18  . . . retainer locking portion 
           19  . . . standing piece 
           20  . . . folded piece 
           22  . . . retainer locking surface 
           26  . . . lance locking surface