Patent Publication Number: US-8992244-B2

Title: Terminal fitting

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a terminal fitting. 
     2. Description of the Related Art 
     A conventional terminal fitting is disclosed in Japanese Unexamined Patent Publication No. 2000-285983. This includes a main portion connectable to a mating terminal fitting, a wire barrel portion to be crimped and connected to a core at an end portion of a wire, an insulation barrel portion to be crimped and connected to an insulation coating at the end portion of the wire and a coupling portion located between the wire barrel portion and the main portion. Further, a heat shrinkable tube is mounted on a part from the insulation barrel portion to the coupling portion. A connecting part between the terminal fitting and the wire is made waterproof by this heat shrinkable tube. 
     In the case of the conventional terminal fitting, the leading end of the heat shrinkable tube is open. Thus, water may enter through the leading end of the heat shrinkable tube to come into contact with the core. In view of this, if a waterproof wall for partitioning between the wire barrel portion and the main portion in a liquid-tight manner is provided between them and the heat shrinkable tube is mounted in close contact with this waterproof wall, the contact of water with the core can be prevented. However, in this case, the waterproof wall may possibly be displaced in a direction away from the wire barrel portion. Then, there is a problem that the leading end of the heat shrinkable tube does not reach the waterproof wall and the contact of water with the core cannot be reliably avoided. 
     The present invention was completed based on the above situation and an object thereof is to provide a terminal fitting capable of maintaining high waterproof property. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above object, a first aspect of the present invention is directed to a terminal fitting to be connected to an end portion of a wire, comprising a main portion connectable to a mating terminal fitting; a barrel portion to be crimped and connected to a core at the end portion of the wire; a waterproof wall to be mounted between the barrel portion and the main portion to partition between the barrel portion and the main portion in a liquid-tight manner; a restricting portion configured to restrict a movement of the waterproof wall toward the main portion by coming into contact with the waterproof wall from the main portion side; and a tube to be held in close contact with the barrel portion and the waterproof wall while surrounding the core. 
     According to a second aspect of the present invention, in the terminal fitting according to the first aspect, the restricting portion is formed by being bent from a coupling portion located between the main portion and the barrel portion. 
     According to a third aspect of the present invention, in the terminal fitting according to the first or second aspect, the restricting portion includes a first restricting portion which comes into contact with the waterproof wall from the main portion side and a second restricting portion which comes into contact with the waterproof wall from the barrel portion side. 
     According to a fourth aspect of the present invention, in the terminal fitting according to the third aspect, a space into which the waterproof wall is to be positioned and inserted is formed between the first and second restricting portions. 
     Since the tube is held in close contact with the barrel portion and the waterproof wall while surrounding the core, the contact of water with the core can be prevented and waterproof property can be ensured. Further, since the movement of the waterproof wall toward the main portion is restricted by the contact of the restricting portion with the waterproof wall from the main portion side, the tube can be reliably held in close contact with the waterproof wall and high waterproof property can be maintained. 
     Since the restricting portion is formed by being bent from the coupling portion located between the main portion and the barrel portion, formability is excellent without particularly complicating the structure of the restricting portion. 
     Since the restricting portion includes the second restricting portion that comes into contact with the waterproof wall from the barrel portion side in addition to the first restricting portion, a movement of the waterproof wall toward the barrel portion can also be restricted and reliability in movement restriction can be improved. Further, even if the waterproof wall is thinned to such an extent that it is difficult to stand alone, it can be supported by the first and second restricting portions. The waterproof wall can be thinned and the entire length of the terminal fitting can be correspondingly made shorter. 
     Since the space into which the waterproof wall is to be positioned and inserted is formed between the first and second restricting portions, a displacement of the waterproof wall can be prevented and the tube can be reliably held in close contact with the waterproof wall at a predetermined position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged perspective view of an essential part showing a state before a waterproof wall is mounted in a terminal fitting according to a first embodiment of the present invention. 
         FIG. 2  is a side view in section. 
         FIG. 3  is a section along A-A of  FIG. 2 . 
         FIG. 4  is an enlarged section showing an essential part in a terminal fitting according to a second embodiment. 
         FIG. 5  is an enlarged plan view showing an essential part with a part of a heat shrinkable tube shown in section. 
         FIG. 6  is a section along B-B of  FIG. 5 . 
         FIG. 7  is an enlarged section showing an essential part in a terminal fitting according to a third embodiment. 
         FIG. 8  is a section along C-C of  FIG. 7 . 
         FIG. 9  is an enlarged plan view showing an essential part with a part of a heat shrinkable tube shown in section in a terminal fitting according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first embodiment of the present invention is described with reference to  FIGS. 1 to 3 . A terminal fitting  10  according to the first embodiment includes a terminal main body  20 , a waterproof wall  60  and a heat shrinkable tube  70  and is connected to an end portion of a wire  90  as shown in  FIG. 2 . 
     The terminal main body  20  is integrally formed, such as by bending a metal plate made of copper or copper alloy and composed of a main portion  21 , barrel portions  22 ,  23  located behind the main portion  21 , a coupling portion  24  located between the barrel portions  22 ,  23  and the main portion  21  to couple them, and a restricting portion  25  formed integrally to the coupling portion  24 . 
     The main portion  21  is formed into a substantially rectangular tubular shape with open front and rear surfaces by bending the metal plate in a width direction a plurality of times. A resilient contact piece  26  is formed in the main portion  21 . The resilient contact piece  26  is in the form of a cantilever folded backward from the front end of a bottom wall  27  of the main portion  21  and resiliently deformable upward and downward with the front end of the bottom wall  27  as a supporting point. When the terminal fitting  10  is connected to an unillustrated mating terminal fitting, a tab of the mating terminal fitting is inserted into the main portion  21  from front and resiliently comes into contact with the resilient contact piece  26 , whereby the two terminal fittings are electrically connected. 
     The barrel portions  22 ,  23  are composed of the wire barrel portion  22  and the insulation barrel portion  23  located behind the wire barrel portion  22 . The wire barrel portion  22  and the insulation barrel portion  23  are both in the form of an open barrel and crimped and connected to the end portion of the wire  90 . 
     The wire  90  is composed of a core made of aluminum or aluminum alloy and formed by twisting a plurality of strands, and an insulation coating  92  made of resin and surrounding the core  91 . The insulation coating  92  is stripped at a front end portion of the wire  90  to expose the core  91 . 
     The wire barrel portion  22  is crimped and connected to the core  91  from an outer side, and the insulation barrel portion  23  is crimped and connected to the insulation coating  92  from an outer side. A part of the front end portion of the core  91 , to which the wire barrel portion  22  is crimped and connected, before the front end of the wire barrel portion  22  is bent up as shown in  FIG. 2 . 
     As shown in  FIG. 3 , the coupling portion  24  has a substantially U-shaped cross-section and includes a bottom plate portion  28  and a pair of side plate portions  29 ,  31  standing up from opposite lateral edges of the bottom plate portion  28 . The bottom plate portion  28  is connected to a bottom wall  27  of the main portion  21  without forming any step as shown in  FIG. 2 . Further, the bottom plate portion  28  is gradually narrowed from the main portion  21  toward the wire barrel portion  22 . 
     As shown in  FIG. 1 , the restricting portion  25  includes a restricting main body  32  bridging between the upper end of one side plate portion (hereinafter, referred to as the first side plate portion  29 ) out of the both side plate portions  29 ,  31  and that of the other side plate portion (hereinafter, referred to as the second side plate portion  31 ). The restricting main body  32  is substantially horizontally arranged along the width direction and includes a base end portion  34  connected substantially at a right angle to the upper end of the first side plate portion  29  and a leading end portion  35  held in contact with the upper end of the second side plate portion  31  from above. 
     Further, the restricting main body  32  is in the form of a rectangular frame and includes a pair of short side portions  33  facing each other in the width direction and extending substantially parallel to forward and backward directions and a pair of long side portions  36 ,  37  facing each other in forward and backward directions and extending substantially parallel to the width direction. A rectangular space  38  is defined by the both long side portions  36 ,  37  and the both short side portions  33 . 
     A waterproof wall  60  is inserted and fitted into the space  38  of the restricting main body  32  from above. In this case, as shown in  FIG. 2 , the front long side portion near the main portion  21  out of the both long side portions  36 ,  37  serves as a first restricting portion  36  for restricting a forward movement of the waterproof wall  60  and the rear long side portion near the wire barrel portion  22  serves as a second restricting portion  37  for restricting a backward movement of the waterproof wall  60 . Further, as shown in  FIG. 3 , loose movements of the waterproof wall  60  in the width direction are restricted by the both short side portions  33 . 
     The waterproof wall  60  is made of resin and substantially in the form of a rectangular block and has a width substantially equal to a distance between the inner surfaces of the both side plate portions  29 ,  31  and a height exceeding a distance from the inner surface of the bottom plate portion  28  to the space  38  of the restricting portion  25  as shown in  FIG. 3 . Further, the waterproof wall  60  is press-fitted into the space  38  of the restricting portion  25  and positioned and held in the space  38 . 
     The heat shrinkable tube  70  is in the form of a tube long and narrow in forward and backward directions and mounted to cover from the insulation coating  92  at the end portion of the wire  90  to the waterproof wall  60  over the entire circumference as shown in  FIG. 2 . This heat shrinkable tube  70  is made of a synthetic resin material which shrinks upon being heated, and an unillustrated contact layer or adhesive layer is formed on the inner circumferential surface. Note that, in the case of this embodiment, the heat shrinkable tube  70  of a known type can be used. 
     Next, functions of the terminal fitting  10  according to the first embodiment are described. 
     As shown in  FIG. 1 , the waterproof wall  60  is press-fitted into the space  38  of the restricting portion  25  from above. Then, the bottom surface and the opposite side surfaces of the waterproof wall  60  respectively come into contact with the inner surfaces of the bottom plate portion  28  and the both side plate portions  29 ,  31  and the outer periphery of the upper end of the waterproof wall  60  is held in contact with the first and second restricting portions  36 ,  37  and the both short side portions  33  over the entire circumference. In this way, the waterproof wall  60  is positioned and held in the coupling portion  24 . Further, the main portion  21  and the wire barrel portion  22  are partitioned in a liquid-tight manner by the waterproof wall  60  and the flow of water or the like can be blocked by the waterproof wall  60 . 
     Subsequently, the heat shrinkable tube  70  in an unheated state is loosely fitted on the above terminal fitting  10  to surround the core  91  and areas before and after the core  91 . Subsequently, the heat shrinkable tube  70  is heated and thermally shrunk. Then, a rear end portion of the heat shrinkable tube  70  is held in close contact with the insulation coating  92  at the end portion of the wire  90  over the entire circumference as shown in  FIG. 2  and a front end portion of the heat shrinkable tube  70  is held in close contact with a part of the waterproof wall  60  projecting upward from the space  38 , a substantially rear half of the restricting portion  25  and a substantially rear half of the coupling portion  24  as shown in  FIG. 3 . Further, the heat shrinkable tube  70  is also held in close contact with the insulation barrel portion  23 , the wire barrel portion  22  and a part of the core  91  not covered by the wire barrel portion  22 . In this way, the above respective parts are collectively surrounded by the heat shrinkable tube  70  and the heat shrinkable tube  70  is fixed while being held in close contact without forming any clearance in conformity with the outer shapes of the above respective parts. 
     As described above, according to the first embodiment, the contact of water with the core  91  can be prevented and predetermined waterproof property can be ensured since the heat shrinkable tube  70  is held in close contact with the wire barrel portion  22 , the insulation barrel portion  23  and the waterproof wall  60  while surrounding the core  91 . As a result, a situation can be prevented where electrolytic corrosion occurs using water as an intermediary because the terminal fitting  10  and the core  91  are made of dissimilar metals. 
     Further, because of the presence of the first restricting portion  36  for restricting a movement of the waterproof wall  60  toward the main portion  21  by the contact of the restricting portion  25  with the waterproof wall  60  from the main portion  21  side, the heat shrinkable tube  70  can be reliably held in close contact with the waterproof wall  60  and high waterproof property can be maintained. 
     Further, since the restricting portion  25  is formed by being bent from the coupling portion  24  located between the main portion  21  and the wire barrel portion  22 , the structure thereof does not become particularly complicated. 
     Furthermore, since the restricting portion  25  includes the second restricting portion  37  that comes into contact with the waterproof wall  60  from the side of the wire barrel portion  22  and the insulation barrel portion  23  in addition to the first restricting portion  36 , a movement of the waterproof wall  60  toward the wire barrel portion  22  and the insulation barrel portion  23  is also restricted and reliability in movement restriction can be improved. In this case, even if the waterproof wall  60  is thinned to such an extent that it is difficult to stand alone, it can be supported by the first and second restricting portions  36 ,  37 . Thus, the waterproof wall  60  can be thinned and the entire length of the terminal fitting  10  can be correspondingly made shorter. 
     Further, since the space  38  into which the waterproof wall  60  is to be positioned and inserted is formed between the first and second restricting portions  36 ,  37 , a displacement of the waterproof wall  60  can be prevented and the heat shrinkable tube  70  can be reliably held in close contact with the waterproof wall  60  at a predetermined position. 
       FIGS. 4 to 6  show a second embodiment of the present invention. In a terminal fitting  10 A according to the second embodiment, the structure of a restricting portion  25 A differs from the first embodiment. The other configurations are similar to the first embodiment, and the configurations similar to the first embodiment are denoted by the same reference signs and not repeatedly described. 
     As shown in  FIG. 4 , the restricting portion  25 A is composed of a first restricting portion  36 A integrally coupled to the rear end of an upper wall  58  of a main portion  21  and a second restricting portion  37 A integrally coupled to the upper end of a first side plate portion  29  of a coupling portion  24 . The first restricting portion  36 A is formed by a first resilient piece  41  extending obliquely downward to the back from a widthwise central part of the rear end of the upper wall  58 . The first resilient piece  41  is resiliently deformable forward and backward with the rear end of the upper wall  58  as a supporting point. A first bent portion  42  bent substantially in L shape is formed at a lower end portion of the first resilient piece  41 . The first bent portion  42  projects more backward than areas above and below it. Further, a part of the first resilient piece  41  above the first bent portion  42  serves as a first guiding portion  43  extending obliquely upward to the front. 
     As shown in  FIG. 5 , the second restricting portion  37 A includes a bridging portion  44  extending from the upper end of the first side plate portion  29  to that of a second side plate portion  31 . The bridging portion  44  is arranged substantially horizontally along the width direction and includes a base end portion  34 A connected substantially at a right angle to the upper end of the first side plate portion  29  and a leading end portion  35 A held in contact with the upper end of the second side plate portion  31  from above. 
     Further, the second restricting portion  37 A includes a second resilient piece  45  extending obliquely downward to the front from a widthwise central part of the front end of the bridging portion  44 . The second resilient piece  45  is resiliently deformable forward and backward with the front end of the bridging portion  44  as a supporting point. As shown in  FIG. 4 , a second bent portion  46  bent substantially in L shape is formed at a substantially central part in an extending direction of the second resilient piece  45 . The second bent portion  46  projects more forward than areas above and below it. Further, a part of the second resilient piece  45  above the second bent portion  46  serves as a second guiding portion  43  extending obliquely upward to the back. 
     As shown in  FIG. 4 , tip portions  48 ,  49  of the first and second bent portions  42 ,  46  are located substantially at the same height position and arranged to face each other in forward and backward directions. As shown in  FIG. 5 , a space  38 A into which a waterproof wall  60  is to be inserted is defined between the respective tip portions  48 ,  49  of the first and second bent portions  42 ,  46 , and has a spacing smaller than the thickness of the waterproof wall  60  in forward and backward directions when the first and second resilient pieces  41 ,  45  are in a natural state. 
     Here, the waterproof wall  60  is inserted into the space  38 A of the restricting portion  25 A from above. In an insertion process, front and rear lower end portions of the waterproof wall  60  respectively slide on the first and second guiding portions  43 ,  47  to guide the waterproof wall  60  into the space  38 A and, according to sliding movements thereof, the first and second resilient pieces  41 ,  45  are resiliently deformed in directions away from each other. When the bottom surface of the waterproof wall  60  comes into contact with a bottom plate portion  28  in this way, the tip portions  48 ,  49  of the first and second resilient pieces  41 ,  45  respectively resiliently come into contact with the both front and rear surfaces of the waterproof wall  60 , whereby the waterproof wall  60  is positioned and resiliently held in the restricting portion  25 A. Thereafter, a heat shrinkable tube  70  is mounted on the terminal fitting  10 A and heated, thereby being held in close contact with and fixed to a part of the waterproof wall  60  projecting upward from the space  38 A and a substantially rear half of the coupling portion  24 , the second restricting portion  37 A, a wire barrel portion  22 , a part of a core  91  not covered by the wire barrel portion  22 , an insulation barrel portion  23  and an insulation coating  92  at an end portion of the wire  90 , respectively. 
     According to the second embodiment, the spacing of the space  38 A of the restricting portion  25 A needs not coincide with the thickness of the waterproof wall  60  in forward and backward directions and strict gap management is not necessary since the waterproof wall  60  is resiliently held in the restricting portion  25 A. 
       FIGS. 7 and 8  show a third embodiment of the present invention. A terminal fitting  10 B according to the third embodiment also differs from the first embodiment in the structure of a restricting portion  25 B. 
     The restricting portion  25 B is integrally coupled to both side plate portions  29 ,  31  of a coupling portion  24 . Specifically, as shown in  FIG. 8 , the restricting portion  25 B is composed of a pair of projecting pieces  51  bent inwardly substantially at a right angle from the upper ends of the both side plate portions  29 ,  31 . The both projecting pieces  51  are in the form of rectangular plates and substantially horizontally arranged substantially at the same height position. The projecting ends of the both projecting pieces  51  are spaced apart by a distance shorter than the width of a waterproof wall  60 B. Further, the rear ends of the both projecting pieces  51  and the front end of a core  91  are spaced apart by a distance longer than the thickness of the waterproof wall  60 B in forward and backward directions. 
     The waterproof wall  60 B has a larger thickness than the waterproof walls  60  of the first and second embodiments in forward and backward directions and can at least stand alone. The waterproof wall  60 B is inserted behind the restricting portion  25 B in the coupling portion  24 . Then, the both projecting pieces  51  are arranged to face each other before the waterproof wall  60 B. Thus, the front surface of the waterproof wall  60 B comes into contact with the rear ends of the both projecting pieces  51 , whereby any further forward movement of the waterproof wall  60 B is prevented. 
     When being mounted on the terminal fitting  10 B and heated, a heat shrinkable tube  70  is held in close contact with a connecting part of the terminal fitting  10 B and a wire  90  and a front end portion of the heat shrinkable tube  70  is held in close contact with and fixed to an upper end portion of the waterproof wall  60 B. Since the restricting portion  25 B has a relatively simple structure according to the third embodiment, cost can be reduced due to easy production. 
       FIG. 9  shows a fourth embodiment of the present invention. A terminal fitting  10 C according to the fourth embodiment also differs from the first embodiment in the structure of a restricting portion  25 C. 
     The restricting portion  25 C is integrally coupled to both side plate portions  29 ,  31  of a coupling portion  24 . Specifically, the restricting portion  25 C is composed of a pair of first restricting portions  36 C formed by bending the both side plate portions  29 ,  31  inwardly at positions near a main portion  21  to have a substantially U-shaped cross-section and a pair of second restricting portions  37 C likewise formed by bending the both side plate portions  29 ,  31  inwardly at positions behind the first restricting portions  36 C to have a substantially U-shaped cross-section. The first and second restricting portions  36 C,  37 C are formed by hammering the both side plate portions  29 ,  31  from outer sides. Further, the first restricting portions  36 C are located substantially at the same position in forward and backward directions and vertically extend. Similarly, the second restricting portions  37 C are located substantially at the same position in forward and backward directions and vertically extend. 
     A space  38 C is formed to be open upward between the first and second restricting portions  36 C,  37 C and a waterproof wall  60  is inserted into the space  38 C from above. The front surface of the waterproof wall  60  is arranged to be able to come into contact with the both first restricting portions  36 C and the rear surface of the waterproof wall  60  is arranged to be able to come into contact with the both second restricting portions  37 C by fitting the waterproof wall  60  into the space  38 C. Further, the bottom surface of the waterproof wall  60  is arranged to be able to come into contact with a bottom plate portion  28  and the opposite side surfaces of the waterproof wall  60  are arranged to be able to come into contact with the both side plate portions  29 ,  31 . In this way, the waterproof wall  60  is positioned and held in the space  38 C of the restricting portion  25 C. 
     When being mounted on the terminal fitting  10 C and heated, a heat shrinkable tube  70  is held in close contact with a connecting part of the terminal fitting  100  and a wire  90  and a front end portion of the heat shrinkable tube  70  is held in close contact with and fixed to an upper end portion of the waterproof wall  60 . Since the waterproof wall  60  is positioned and held by the restricting portion  25 C having a relatively simple structure according to the fourth embodiment, cost effectiveness is excellent. 
     The present invention is not limited to the above described and illustrated embodiments. For example, the following embodiments are also included in the technical scope of the present invention. 
     The core of the wire and the terminal fitting may be made of similar metals. For example, the core may be made of copper or copper alloy. 
     The terminal fitting may be a male terminal fitting with a main portion including a tab projecting forward. Further, the terminal fitting may be a round terminal (LA terminal) with a ring-shaped main portion. 
     The barrel portion may be composed only of the wire barrel portion without including the insulation barrel portion. 
     An elastic tube such as a rubber tube may be used in place of the heat shrinkable tube. 
     The waterproof wall has a rectangular shape in the above embodiments. However, if the terminal main body has a semicircular bottom shape, the waterproof wall may correspondingly have a circular shape.