Patent Publication Number: US-11398686-B2

Title: Wire, wire with terminal, harness, manufacturing method for wire, and manufacturing method for wire with terminal

Description:
FIELD 
     The present invention relates to a wire, a wire with terminal, a harness, a manufacturing method for a wire, and a manufacturing method for a wire with a terminal. 
     BACKGROUND 
     Japanese Unexamined Patent Application Publication No. 2015-115308 discloses an aluminum wire  102  composed of a core wire  100  and an insulation coating  101  as shown in  FIG. 32  of the present application. The insulation coating  101  has a partially peeled part  103  so that the core wire  100  is exposed. A terminal  104  has a rib  106  with a rectangular frame shape along the periphery of a swaging part  105 , and the rib  106  bites into the insulation coating  101 , and thereby the partially peeled part  103  is sealed. 
     SUMMARY 
     However, Japanese Unexamined Patent Application Publication No. 2015-115308 mentions nothing about sealing a distal end surface of the core wire. 
     An object of the present invention is to provide a technique to reliably seal a distal end surface of a core wire as well as preventing a distal end coating part that covers a distal end of the core wire from coming off. 
     According to a first aspect of the present invention, there is provided a wire including a core wire and an insulation coating that covers an outer periphery of the core wire, wherein the core wire includes a distal end region containing a distal end surface of the core wire, and a body region being a part other than the distal end region, the distal end region includes a first distal end region containing the distal end surface, and a second distal end region located between the first distal end region and the body region, and the insulation coating includes a distal end coating part that covers an outer periphery of the first distal end region in a tube shape, an insulation coating body that covers an outer periphery of the body region in a tube shape, at least one coating joint part that joins the distal end coating part and the insulation coating body together in such a way that at least part of an outer periphery of the second distal end region is exposed, and a coating extension part that extends from the distal end coating part beyond the distal end surface in a tube shape. 
     A thickness of the coating joint part in a radical direction is preferably smaller than a maximum thickness of the insulation coating body in the radial direction. 
     Preferably, the insulation coating body includes a first body part touching the coating joint part, and a second body part located farther from the distal end surface than the first body part is, a thickness of the first body part in the radial direction is the same as the thickness of the coating joint part in the radial direction, and a thickness of the second body part in the radial direction is greater than the thickness of the first body part in the radial direction. 
     Preferably, a welded part having been crushed in a cross direction crossing a longitudinal direction of the wire and closed by welding is formed in the coating extension part. 
     When viewing in the longitudinal direction of the wire, a center of gravity of a cross-section of the welded part orthogonal to the longitudinal direction of the wire and a center of gravity of a cross-section of the distal end coating part orthogonal to the longitudinal direction of the wire preferably do not coincide. 
     The welded part is preferably formed to avoid a virtual extension line of a central axis of the core wire. 
     A cross-sectional shape of the welded part orthogonal to the longitudinal direction of the wire is preferably a track shape, an ellipse, a U-shape, or a V-shape. 
     The cross direction is preferably a direction orthogonal to the longitudinal direction of the wire. 
     Preferably, an internal space of the coating extension part is filled with a sealing material, or a sealing member is inserted into the internal space of the coating extension part. 
     Preferably, there is provided a wire with a terminal including the above-described wire, and a terminal attached to the wire, wherein the terminal includes an electrical contact part capable of coming into electrical contact with a mating terminal, a wire crimp part to be crimped onto the wire, and a terminal joint part that joins the electrical contact part and the wire crimp part together, and the wire crimp part includes two crimp pieces, and each of the crimp pieces is crimped onto the distal end coating part, the second distal end region, and the insulation coating body, and thereby the second distal end region is sealed, or the wire crimp part is formed in a tube shape and crimped onto the distal end coating part, the second distal end region, and the insulation coating body, and thereby the second distal end region is sealed. 
     When viewing the wire crimp part from the electrical contact part in the longitudinal direction of the wire, a center of gravity of a cross-section of the welded part orthogonal to the longitudinal direction of the wire is preferably located between a center of gravity of a cross-section of the distal end coating part orthogonal to the longitudinal direction of the wire and the terminal joint part. 
     Preferably, there is provided a harness including the above-described wire, and a housing that accommodates the wire with the terminal. 
     Preferably, there is provided a wire with a terminal including the above-described wire, and a terminal attached to the wire, wherein the terminal includes an electrical contact part capable of coming into electrical contact with a mating terminal, a wire crimp part to be crimped onto the wire, and a terminal joint part that joins the electrical contact part and the wire crimp part together, and the wire crimp part includes two crimp pieces, and each of the crimp pieces is crimped onto the distal end coating part, the second distal end region, and the insulation coating body, and thereby the second distal end region is sealed, or the wire crimp part is formed in a tube shape and crimped onto the distal end coating part, the second distal end region, and the insulation coating body, and thereby the second distal end region is sealed. 
     Preferably, there is provided a harness including the above-described wire, and a housing that accommodates the wire with terminal. 
     According to a second aspect of the present invention, there is provided a manufacturing method for a wire, including an exposing step of exposing at least part of a core wire by making a hole in an insulation coating that covers the core wire, and a stretching step of stretching the insulation coating in such a way that the insulation coating extends beyond a distal end surface of the core wire. 
     Preferably, the stretching step is performed after the exposing step, and in the stretching step, the insulation coating is stretched in such a way that the hole made in the exposing step is enlarged. 
     Preferably, the exposing step is performed after the stretching step, and in the exposing step, the hole is made in a part having become thinner than before stretching as a result of having been stretched in the stretching step. 
     The manufacturing method preferably further includes a slit cutting step of cutting, in the insulation coating, at least two first slits extending in the longitudinal direction of the core wire and separating from each other in a circumferential direction, wherein the stretching step is performed after the slit cutting step, the exposing step is performed after the stretching step, in the stretching step, the insulation coating is stretched in such a way that the at least two first slits cut in the slit cutting step are elongated, and in the exposing step, at least two second slits are cut to connect corresponding ends of the at least two first slits, and thereby the hole is made in the insulation coating. 
     The manufacturing method preferably further includes a step of crushing a part of the insulation coating extending beyond the distal end surface of the core wire in a cross direction crossing a longitudinal direction of the core wire, and a step of closing the crushed part by welding. 
     The manufacturing method preferably further includes a step of filling a sealing material or inserting a sealing member into an internal space of a part of the insulation coating extending beyond the distal end surface of the core wire. 
     According to a third aspect of the present invention, there is provided a manufacturing method for a wire with a terminal, the method manufacturing the wire with the terminal by attaching the terminal to the wire including a core wire and an insulation coating that covers the core wire, including an exposing step of exposing at least part of the core wire by making a hole in the insulation coating, a stretching step of stretching the insulation coating in such a way that the insulation coating extends beyond a distal end surface of the core wire, a crimping step of crimping a crimp piece of the terminal onto the wire so as to seal a part where the core wire is exposed, and a sealing step of sealing the distal end surface of the core wire by welding a part of the insulation coating extending beyond the distal end surface of the core wire after the crimping step. 
     According to the present invention, it is able to effectively seal the distal end surface by using the coating extension part as well as preventing the distal end coating part from coming off the core wire. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a harness (first embodiment). 
         FIG. 2  is a perspective view of a wire with a terminal (first embodiment). 
         FIG. 3  is a perspective view of a wire before a terminal is attached (first embodiment). 
         FIG. 4  is a front view of the wire before the terminal is attached thereto (first embodiment). 
         FIG. 5  is a front cross-sectional view of the wire before the terminal is attached thereto (first embodiment). 
         FIG. 6  is a left side view of the wire before the terminal is attached thereto (first embodiment). 
         FIG. 7  is a perspective view of the terminal before being attached to the wire (first embodiment). 
         FIG. 8  is a partially cutaway perspective view of the terminal before being attached to the wire (first embodiment). 
         FIG. 9  is a front view of the terminal before being attached to the wire (first embodiment). 
         FIG. 10  is a perspective view of the terminal and the wire immediately before the terminal is crimped onto the wire (first embodiment). 
         FIG. 11  is a front cross-sectional view of the terminal and the wire immediately before the terminal is crimped onto the wire (first embodiment). 
         FIG. 12  is a perspective view of the terminal and the wire after the terminal is crimped onto the wire (first embodiment). 
         FIG. 13  is a cross-sectional view along line XIII-XIII of  FIG. 12  (first embodiment). 
         FIG. 14  is a cross-sectional view along line XIII-XIII of  FIG. 12  (first embodiment). 
         FIG. 15  is a partial front view of the terminal and the wire after the terminal is crimped onto the wire (first embodiment). 
         FIG. 16  is a cross-sectional view along line XVI-XVI of  FIG. 12  (first embodiment). 
         FIG. 17  is a partially cutaway perspective view of the harness (first embodiment). 
         FIG. 18  is a partial front cross-sectional view of the harness (first embodiment). 
         FIG. 19  is a flowchart of a manufacturing method for a wire with a terminal (first embodiment). 
         FIG. 20A  is a view illustrating each step of the manufacturing method for a wire with a terminal (first embodiment). 
         FIG. 20B  is a view illustrating each step of the manufacturing method for a wire with a terminal (first embodiment). 
         FIG. 20C  is a view illustrating each step of the manufacturing method for a wire with a terminal (first embodiment). 
         FIG. 21  is a perspective view of a processing jig (first embodiment). 
         FIG. 22  is a flowchart of a manufacturing method for a wire with a terminal (second embodiment). 
         FIG. 23A  is a view illustrating each step of the manufacturing method for a wire with a terminal (second embodiment). 
         FIG. 23B  is a view illustrating each step of the manufacturing method for a wire with a terminal (second embodiment). 
         FIG. 23C  is a view illustrating each step of the manufacturing method for a wire with a terminal (second embodiment). 
         FIG. 23D  is a view illustrating each step of the manufacturing method for a wire with a terminal (second embodiment). 
         FIG. 24  is a flowchart of a manufacturing method for a wire with a terminal (third embodiment). 
         FIG. 25A  is a view illustrating each step of the manufacturing method for a wire with a terminal (third embodiment). 
         FIG. 25B  is a view illustrating each step of the manufacturing method for a wire with a terminal (third embodiment). 
         FIG. 25C  is a view illustrating each step of the manufacturing method for a wire with a terminal (third embodiment). 
         FIG. 25D  is a view illustrating each step of the manufacturing method for a wire with a terminal (third embodiment). 
         FIG. 26  is an enlarged perspective view of a welded part (fourth embodiment). 
         FIG. 27  is a partial front cross-sectional view of a wire (fifth embodiment). 
         FIG. 28  is a partial perspective view of a wire with a terminal (sixth embodiment). 
         FIG. 29  is a perspective view of a wire in which only a coating joint part is thin (first modified example). 
         FIG. 30  is a flowchart of a manufacturing method for a wire with a terminal (second modified example). 
         FIG. 31  is a view showing the way a wire is sealed by welding after a terminal is crimped onto the wire (second modified example). 
         FIG. 32  is a view showing, in a simplified manner, FIG. 9 of Patent Literature 1. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     A first embodiment is described hereinafter with reference to  FIGS. 1 to 21 . 
       FIG. 1  is a perspective view of a harness  1 . As shown in  FIG. 1 , the harness  1  includes a housing  2  made of insulating resin and a plurality of wires with terminal  3  to be accommodated in the housing  2 . In  FIG. 1 , only one wire with terminal  3  among the plurality of wires with terminal  3  is shown, and the other wires with terminal  3  are not shown. 
       FIG. 2  is a perspective view of the wire with terminal  3 . As shown in  FIG. 2 , the wire with terminal  3  includes a wire  4  and a terminal  5  that is attached to the wire  4 . 
     &lt;Wire  4 &gt; 
       FIG. 3  is a perspective view of the wire  4  before the terminal  5  is attached thereto.  FIG. 4  is a front view of the wire  4  before the terminal  5  is attached thereto.  FIG. 5  is a front cross-sectional view of the wire  4  before the terminal  5  is attached thereto. In  FIG. 5 , the scale is adjusted for dimensional notation.  FIG. 6  is a left side view of the wire  4  before the terminal  5  is attached thereto. As shown in  FIGS. 3 and 4 , the wire  4  includes a core wire  6  and an insulation coating  7  that covers the outer periphery of the core wire  6 . 
     The core wire  6  is a stranded wire consisting of a plurality of individual wires twisted together, or an aluminum conductor steel-reinforced cable consisting of hard-drawn aluminum wires twisted together around a galvanized steel wire. The material of the individual wires of the stranded wire may be copper, aluminum, or an aluminum alloy, for example. The individual wires of the stranded wire may be plated individually. In this embodiment, the core wire  6  is a stranded wire consisting of a plurality of individual wires made of an aluminum alloy twisted together. 
     As shown in  FIG. 4 , the core wire  6  includes a distal end region  9  and a body region  10 . The distal end region  9  is a part including a distal end surface  11  of the core wire  6 . The body region  10  is a part other than the distal end region  9  of the core wire  6 . The distal end region  9  and the body region  10  are adjacent to each other in the longitudinal direction of the wire  4 . Hereinafter, the “longitudinal direction of the wire  4 ” is also referred to simply as “wire direction”. The distal end region  9  and the body region  10  are located in this recited order in the direction of drawing away from the distal end surface  11 . The distal end region  9  is located between the distal end surface  11  and the body region  10  in the wire direction. The distal end region  9  includes a first distal end region  12  and a second distal end region  13 . The first distal end region  12  is a part including the distal end surface  11  of the core wire  6 . The second distal end region  13  is a part other than the first distal end region  12  of the distal end region  9 . The first distal end region  12  and the second distal end region  13  are adjacent to each other in the wire direction. The first distal end region  12  and the second distal end region  13  are located in this recited order in the direction of drawing away from the distal end surface  11 . The second distal end region  13  is located between the first distal end region  12  and the body region  10 . 
     The insulation coating  7  is weldable synthetic resin such as vinyl chloride, for example. “Welding” includes heat welding, ultrasonic welding, and laser welding, for example. 
     The insulation coating  7  includes a distal end coating part  15 , an insulation coating body  16 , a coating joint part  17 , and a coating extension part  18 . The coating extension part  18 , the distal end coating part  15 , the coating joint part  17  and the insulation coating body  16  are located in this recited order in the wire direction. 
     The distal end coating part  15  is formed in a tube shape and covers the outer periphery of the first distal end region  12 . As shown in  FIG. 5 , the distal end coating part  15  has a thickness  15 T in the radial direction. 
     Referring back to  FIG. 4 , the insulation coating body  16  is formed in a tube shape and covers the outer periphery of the body region  10 . The insulation coating body  16  includes a first body part  19  and a second body part  20 . The first body part  19  and the second body part  20  are adjacent to each other in the wire direction. The first body part  19  is located closer to the distal end surface  11  than the second body part  20  is. The second body part  20  is located farther from the distal end surface  11  than the first body part  19  is. The first body part  19  touches the coating joint part  17  in the wire direction. As shown in  FIG. 5 , the first body part  19  has a thickness  19 T in the radial direction. The second body part  20  has a thickness  20 T in the radial direction. The thickness  20 T is greater than the thickness  19 T. The thickness  20 T corresponds to the maximum thickness of the insulation coating body  16 . 
     Referring back to  FIG. 4 , the coating joint part  17  is a part that joins the distal end coating part  15  and the insulation coating body  16  together. The coating joint part  17  is elongated in the wire direction in such a way that at least part of the outer periphery of the second distal end region  13  is exposed. The central angle of the coating joint part  17  is 5 to 60 degrees, preferably 10 to 45 degrees, and more preferably 15 to 30 degrees. As the central angle of the coating joint part  17  is greater, the sealing effect of the coating joint part  17  increases, and as the central angle of the coating joint part  17  is smaller, the contact reliability between the terminal  5  and the core wire  6  increases. In this embodiment, the distal end coating part  15  and the insulation coating body  16  are joined by one coating joint part  17 . However, the distal end coating part  15  and the insulation coating body  16  may be joined by a plurality of coating joint parts  17 . As shown in  FIG. 5 , the coating joint part  17  has a thickness  17 T in the radial direction. The thickness  17 T is smaller than the thickness  20 T which corresponds to the maximum thickness of the insulation coating body  16  in the radial direction. The thickness  15 T, the thickness  17 T and the thickness  19 T are equal. 
     Referring back to  FIG. 4 , the coating extension part  18  is a part that extends from the distal end coating part  15  beyond the distal end surface  11  in a tube shape. The coating extension part  18  is a part that does not cover the core wire  6 . The coating extension part  18  is a part that projects in a distal end direction from the distal end coating part  15 . In one specific example, the projecting length of the coating extension part  18  in the wire direction is greater than the outer diameter of the core wire  6 . The “distal end direction” is the direction of viewing the distal end surface  11  from the body region  10  in the wire direction. On the other hand, a “rear end direction” is the direction of viewing the body region  10  from the distal end surface  11  in the wire direction. 
     In this embodiment, a welded part  21  is formed in the coating extension part  18 . The welded part  21  is a tube that is crushed in a vertical direction orthogonal to the wire direction, and it is a part where the internal space of the tube-shaped coating extension part  18  is closed by welding. The welded part  21  extends linearly in the wire direction. As shown in  FIG. 6 , when viewing the wire  4  in the rear end direction, the cross-sectional shape of the welded part  21  orthogonal to the wire direction is a track shape that is asymmetric with respect to a central axis  6 C of the core wire  6  and symmetric in a width direction. In this case, the position of the welded part  21  in a circumferential direction is easily recognizable based on the position of the coating joint part  17  in the circumferential direction. The “width direction” is the direction orthogonal to the vertical direction and the wire direction. The “circumferential direction” is the circumferential direction with respect to the central axis  6 C of the core wire  6 .  FIG. 6  shows a center of gravity  21 G of the cross-section of the welded part  21  and a center of gravity  15 G of the cross-section of the distal end coating part  15  orthogonal to the wire direction. As shown in  FIG. 6 , when viewing in the rear end direction, the center of gravity  21 G of the cross-section of the welded part  21  and the center of gravity  15 G of the cross-section of the distal end coating part  15  do not coincide. As shown in  FIG. 4 , the welded part  21  is formed to avoid a virtual extension line  6 D of the central axis  6 C of the core wire  6 . As shown in  FIG. 6 , a linear weld scar  22  is left on a distal end surface  21 A of the welded part  21 . The weld scar  22  is left as a result of closing the internal space of the tube-shaped coating extension part  18  by welding, and therefore the weld scar  22  extends in a single linear line. 
     Hereinafter, as shown in  FIGS. 1 and 2 , the “wire direction, “distal end direction”, “rear end direction”, “vertical direction” and “width direction” defined in the description of the wire  4  are used in the same manner also in the description of the housing  2  and the terminal  5 . 
     &lt;Terminal  5 &gt; 
     The terminal  5  is described hereinafter with reference to  FIGS. 7 to 9 .  FIG. 7  is a perspective view of the terminal  5  before being attached to the wire  4 .  FIG. 8  is a partially cutaway perspective view of the terminal  5  before being attached to the wire  4 .  FIG. 9  is a front view of the terminal  5  before being attached to the wire  4 . 
     As shown in  FIG. 7 , the terminal  5  includes a wire crimp part  25 , a terminal joint part  26 , and an electrical contact part  27 . The wire crimp part  25 , the terminal joint part  26 , and the electrical contact part  27  are continuously formed in this recited order in the distal end direction. The terminal joint part  26  joins the wire crimp part  25  and the electrical contact part  27  together. 
     The wire crimp part  25  is a part to be crimped onto the wire  4 . As shown in  FIG. 7 , the wire crimp part  25  is formed in an open barrel shape in this embodiment. Specifically, the wire crimp part  25  includes a bottom plate part  28  and two crimp pieces  29 . As shown in  FIG. 8 , the thickness direction of the bottom plate part  28  is substantially parallel to the vertical direction. The two crimp pieces  29  extend upward from the end of the bottom plate part  28  in the width direction. Thus, when viewing the electrical contact part  27  from the wire crimp part  25  in the wire direction, the wire crimp part  25  has a U-shape that opens upward. On an inner surface  30  of each crimp piece  29 , a distal end serration  31 , a center serration  32 , and a rear end serration  33  are formed in this recited order in the rear end direction. In this embodiment, each of the distal end serration  31  and the rear end serration  33  is in the form of a straight gash that extends linearly in the direction orthogonal to the wire direction. Further, in this embodiment, the center serration  32  is in the form of a plurality of recesses arranged in a matrix. 
     The electrical contact part  27  is a part that is capable of coming into electrical contact with a mating terminal, which is not shown. The electrical contact part  27  includes a contact spring piece  35  and a spring protector  36  that accommodates and protects the contact spring piece  35 . 
     As shown in  FIG. 7 , the spring protector  36  is a rectangular tube that extends in the wire direction. As shown in  FIGS. 7 and 8 , the spring protector  36  includes a bottom plate part  37 , two side plate parts  38 , and a top plate part  39  that is opposed to the bottom plate part  37 . The bottom plate part  37  and the top plate part  39  are opposed to each other in the vertical direction. The top plate part  39  is disposed above the bottom plate part  37 . The two side plate parts  38  are opposed to each other in the width direction. As shown in  FIG. 9 , a length  39 D from a distal end  36 A of the spring protector  36  to a rear end  39 B of the top plate part  39  is smaller than a length  38 D from the distal end  36 A of the spring protector  36  to a rear end  38 B of the two side plate parts  38 . Thus, as shown in  FIG. 7 , the top plate part  39  can be regarded as being cut away in close proximity to a rear end  36 B of the spring protector  36 . Note that the rear end  38 B of the two side plate parts  38  shown in  FIG. 9  is capable of coming into contact with a retainer, which is described later, in the wire direction. 
     As shown in  FIG. 8 , the contact spring piece  35  is accommodated in the rectangular tubular spring protector  36  and thereby protected by the spring protector  36 . The contact spring piece  35  is elongated in the wire direction. The contact spring piece  35  is supported like a cantilever beam by the spring protector  36 . 
     As shown in  FIG. 7 , the terminal joint part  26  is a part that joins the wire crimp part  25  and the electrical contact part  27  together. As shown in  FIG. 8 , the terminal joint part  26  includes a bottom plate part  45  and two side plate parts  46 . The thickness direction of the bottom plate part  45  is substantially parallel to the vertical direction. The two side plate parts  46  extend upward from the end of the bottom plate part  45  in the width direction. The bottom plate part  45  joins the bottom plate part  28  of the wire crimp part  25  and the bottom plate part  37  of the spring protector  36  of the electrical contact part  27  together in the wire direction. Likewise, each side plate part  46  joins each crimp piece  29  of the wire crimp part  25  and each side plate part  38  of the electrical contact part  27  together in the wire direction. Since the two side plate parts  46  of the terminal joint part  26  have a lower height than the two crimp pieces  29  of the wire crimp part  25  and the two side plate parts  38  of the electrical contact part  27 , a retainer insertion space  47  where a retainer, which is described later, is able to be inserted is left between the wire crimp part  25  and the electrical contact part  27 . 
     The terminal  5  described above is produced by plating with a base metal, such as tin, nickel or zinc, a single thin plate made of copper or a copper alloy and then pressing it, for example. The terminal  5 , however, may be produced by pressing a thin plate and then plating it. 
     &lt;Wire with Terminal  3 &gt; 
     The wire with terminal  3  is described hereinafter with reference to  FIGS. 10 to 16 .  FIG. 10  is a perspective view of the terminal  4  and the wire  5  immediately before the terminal  4  is crimped onto the wire  5 .  FIG. 11  is a front cross-sectional view of the terminal  4  and the wire  5  immediately before the terminal  4  is crimped onto the wire  5 .  FIG. 12  is a perspective view of the terminal  4  and the wire  5  after the terminal  4  is crimped onto the wire  5 .  FIGS. 13 and 14  are cross-sectional views along line XIII-XIII of  FIG. 12 .  FIG. 15  is a partial front view of the terminal  4  and the wire  5  after the terminal  4  is crimped onto the wire  5 .  FIG. 16  shows another specific example of a cross-sectional view along line XVI-XVI of  FIG. 12 . 
     To crimp the above-described terminal  5  onto the wire  4 , as shown in  FIG. 10 , the wire  4  is first disposed between the two crimp pieces  29  of the wire crimp part  25 . 
     To be specific, as shown in  FIG. 11 , the wire  4  is disposed between the two crimp pieces  29  of the wire crimp part  25  so as to satisfy the following conditions. 
     (1) In the wire direction, the welded part  21  is located toward the rear end direction relative to the contact spring piece  35  shown in  FIG. 8 . This prevents the welded part  21  from inhibiting the movement of the contact spring piece  35 . 
     (2) In the vertical direction, the welded part  21  is disposed in closest proximity to the bottom plate part  45  of the terminal joint part  26 . This allows the retainer insertion space  47  shown in  FIG. 8  to be large. Alternatively, in the wire direction, the welded part  21  may be disposed toward the rear end direction relative to the retainer insertion space  47  shown in  FIG. 8 . This also allows the retainer insertion space  47  shown in  FIG. 8  to be large. Note that, however, when the retainer insertion space  47  is not needed, the disposition of the welded part  21  is arbitrary. 
     (3) In the wire direction, the distal end surface  11  of the core wire  6  is located between the rear end  36 B of the spring protector  36  of the electrical contact part  27  and a distal end  29 A of the two crimp pieces  29  of the wire crimp part  25 . Note that, however, since there is a possibility that the core wire  6  extends and the distal end surface  11  of the core wire  6  shifts in the distal end direction at the time of crimping, the distal end surface  11  of the core wire  6  may be simply located in close proximity to the distal end  29 A of the two crimp pieces  29  of the wire crimp part  25  rather than being located between the rear end  36 B of the spring protector  36  of the electrical contact part  27  and the distal end  29 A of the two crimp pieces  29  of the wire crimp part  25 . 
     (4) In the wire direction, a rear end  15 B of the distal end coating part  15  is located between the distal end serration  31  and the center serration  32 . 
     (5) In the radial direction of the wire  4 , the distal end coating part  15  is opposed to the distal end serration  31 . 
     (6) In the wire direction, the coating joint part  17  is located between the distal end serration  31  and the rear end serration  33 . 
     (7) In the wire direction, a core wire exposure part  23 , which is a part of the core wire  6  exposed between the distal end coating part  15  and the insulation coating body  16 , is located between the distal end serration  31  and the rear end serration  33 . 
     (8) In the radial direction of the wire  4 , the core wire exposure part  23  is opposed to the center serration  32 . 
     (9) In the vertical direction, the core wire exposure part  23  is opposed to the bottom plate part  28  of the wire crimp part  25 . 
     (10) In the vertical direction, the coating joint part  17  is located farthest from the bottom plate part  28  of the wire crimp part  25 . 
     (11) In the radial direction of the wire  4 , the first body part  19  is opposed to the rear end serration  33 . 
     (12) In the radial direction of the wire  4 , the second body part  20  is not opposed to the two crimp pieces  29 . 
     After the wire  4  is disposed between the two crimp pieces  29  of the wire crimp part  25  as described above, the two crimp pieces  29  of the wire crimp part  25  of the terminal  5  are crimped to the wire  4  as shown in  FIG. 12  by using a dedicated crimp tool. To be specific, each crimp piece  29  is crimped to the distal end coating part  15  shown in  FIG. 11 , the coating joint part  17  and the core wire exposure part  23 , and the first body part  19 . At the time of crimping, as shown in  FIGS. 13 and 14 , the two crimp pieces  29  are plastically deformed inward in such a way that the two crimp pieces  29  come into close contact with each other and the two crimp pieces  29  are bent to be convex inward.  FIGS. 13 and 14  show a plurality of individual wires P that constitute the core wire  6 . In  FIGS. 13 and 14 , no hatching is shown on the cross-section of the terminal  5  and the wire  6  for the convenience of description. As shown in  FIGS. 13 and 14 , the coating joint part  17  is crushed in the width direction between the two crimp pieces  29 , so that the coating joint part  17  contributes airtightness between the two crimp pieces  29 . Note that, in the specific example shown in  FIG. 13 , the area of contact between the two crimp pieces  29  is relatively small, and the coating joint part  17  stretches in the vertical direction between the two crimp pieces  29 . On the other hand, in the specific example shown in  FIG. 14 , the area of contact between the two crimp pieces  29  is relatively large, and the coating joint part  17  is deformed into a substantially equilateral triangle between the two crimp pieces  29 . As shown in  FIGS. 13 and 14 , since the cross-sectional area of the coating joint part  17  is small in this embodiment, the coating joint part  17  is not spread out in the width direction at the time of crimping, and therefore inhibition of electrical contact between the individual wires P that constitute the core wire  6  and each crimp piece  29  does not occur. 
     Note that, in the specific example shown in  FIG. 13 , the second distal end region  13  is more reliably sealed than in the specific example shown in  FIG. 14 . Specifically, in the specific example shown in  FIG. 13 , when the two crimp pieces  29  spring back, the coating joint part  17  is crushed in the width direction by the two crimp pieces  29 , and therefore the airtightness between the two crimp pieces  29  is improved. On the other hand, in the specific example shown in  FIG. 14 , when the two crimp pieces  29  spring back, there is a possibility that a gap occurs in the vicinity of the coating joint part  17 , such as between a point of contact between the two crimp pieces  29  and the coating joint part  17 . Hence, as in the specific example shown in  FIG. 13 , it is advantageous for the sealing of the second distal end region  13 , which is, the waterproof capability of the second distal end region  13  that, in the state where the terminal  5  is crimped onto the wire  4 , the two crimp pieces  29  are not in direct contact with each other, and the coating joint part  17  is interposed between the two crimp pieces  29  in the width direction in such a way that the two crimp pieces  29  compress the coating joint part  17  in the width direction. 
     As a result of the above-described crimping, the distal end coating part  15  bites into the distal end serration  31  of each crimp piece  29  shown in  FIG. 11 , and also the first body part  19  bites into the rear end serration  33  of each crimp piece  29 , and consequently the core wire exposure part  23  is successfully sealed by the wire crimp part  25 , the distal end coating part  15  and the first body part  19 . Further, the center serration  32  bites into the core wire exposure part  23 , and consequently a passivation film of the core wire  6  is locally removed, which establishes good continuity of the terminal  5  and the core wire  6 . Note that the distal end surface  11  of the core wire  6  is sealed as a result that the welded part  21  is formed in the coating extension part  18 . 
     As shown in  FIG. 15 , the core wire  6  is located above the terminal joint part  26  between the electrical contact part  27  and the wire crimp part  25 . Specifically, in this embodiment, at least part of the core wire  6  is located above an upper end  46 C of the two side plate parts  46  of the terminal joint part  26  between the electrical contact part  27  and the wire crimp part  25 . In other words, at least part of the core wire  6  is farther from the bottom plate part  45  than the upper end  46 C is. This enables confirmation as to whether the distal end surface  11  of the core wire  6  is located between the electrical contact part  27  and the wire crimp part  25  after crimping by applying an X-ray to the wire with terminal  3  in the width direction. Instead of an X-ray, an ultrasonic wave may be used. 
     Further, as shown in  FIG. 16 , in this embodiment, when viewing the wire crimp part  25  from the electrical contact part  27  in the wire direction, the center of gravity  21 G of the cross-section of the welded part  21  is located between the center of gravity  15 G of the cross-section of the distal end coating part  15  and the bottom plate part  45  of the terminal joint part  26  in the vertical direction. In this structure, as shown in  FIG. 15 , the retainer insertion space  47  into which a retainer, which is described later, is inserted is effectively provided between the electrical contact part  27  and the wire crimp part  25 . 
     &lt;Harness  1 &gt; 
     The harness  1  is described hereinafter with reference to  FIGS. 17 and 18 .  FIG. 17  is a partially cutaway perspective view of the harness  1 .  FIG. 18  is a partial front cross-sectional view of the harness  1 . 
     As shown in  FIG. 17 , the housing  2  includes a housing body  51  having a plurality of cavities  50  into which the wire with terminal  3  is able to be inserted in the wire direction, and a retainer  52  for secondary locking. The retainer  52  is held to be vertically movable with respect to the housing body  51 . The retainer  52  is located opposite to the rear end  36 B of the spring protector  36  of the wire with terminal  3  in the wire direction and thereby controls the detachment of the wire with terminal  3  in the rear end direction. 
     As shown in  FIG. 18 , the retainer  52  has a locking lance  53  that is able to be inserted into the retainer insertion space  47  of the wire with terminal  3 . Then, as shown in  FIG. 18 , when the retainer  52  is pulled down, the locking lance  53  is inserted into the retainer insertion space  47  of the wire with terminal  3 , and the locking lance  53  thereby becomes capable of coming into contact with the rear end  36 B of the spring protector  36  in the wire direction. In other words, when the retainer  52  is pulled down, the locking lance  53  becomes capable of coming into contact with the rear end  38 B of each side plate part  38  of the spring protector  36  shown in  FIG. 9 . Thus, even when the wire with terminal  3  is tried to pull out of the housing  2 , the rear end  36 B of the spring protector  36  catches on the locking lance  53 , thereby prohibiting the wire with terminal  3  from being pulled out of the housing  2 . 
     &lt;Manufacturing Method for Wire with Terminal  3 &gt; 
     A manufacturing method for the wire  4  and a manufacturing method for the wire with terminal  3  are described hereinafter with reference to  FIGS. 19 to 21 .  FIG. 19  is a flowchart of a manufacturing method for the wire with terminal  3 .  FIGS. 20A to 20C  are views illustrating each step of the manufacturing method for the wire with terminal  3 .  FIG. 21  is a perspective view of a processing jig. 
     Step S 100 : Exposing Step 
     First, as shown in  FIG. 20A , the insulation coating  7  is partly removed in close proximity to the distal end surface  11  of the core wire  6 , so that the insulation coating  7  has a core wire exposure hole  60  (hole). The coating joint part  17  is thereby formed, and a core wire exposure part  23  is also made. A method of partly removing the insulation coating  7  may be (1) a method including a step of cutting a slit in the insulation coating  7  with a cutting tool, (2) a method including a step of cutting a slit in the insulation coating  7  by laser processing, (3) a method including a step of partly evaporating the insulation coating  7  by laser processing, and so on. 
     Step S 110 : Stretching Step 
     Next, as shown in  FIG. 20B , the insulation coating  7  is stretched in the distal end direction in such a way that the insulation coating  7  extends beyond the distal end surface  11 . To be specific, the insulation coating  7  is stretched in the distal end direction in such a way that the opening area of the core wire exposure hole  60  made in Step S 100  is enlarged. To be more specific, the insulation coating  7  is stretched in the distal end direction in such a way that the coating joint part  17  formed in Step S 100  becomes thinner than that before stretching. It is preferred to use a processing jig  61  shown in  FIG. 21  in order to stretch the insulation coating  7  without splitting it. The processing jig  61  includes an upper jig  62  and a lower jig  63 . The wire  4  is sandwiched between the upper jig  62  and the lower jig  63 , and then the processing jig  61  is moved in the distal end direction while the wire  4  is heated indirectly through the upper jig  62  and the lower jig  63 . As a result, as shown in  FIG. 20B , the coating extension part  18 , which is a part of the insulation coating  7  extending beyond the distal end surface  11  in the distal end direction, is formed. 
     Step S 120 : Sealing Step 
     Then, as shown in  FIG. 20C , the coating extension part  18  is crushed in the vertical direction, and the crushed part is closed by welding, and thereby the welded part  21  is formed in the coating extension part  18 . The distal end surface  11  is thereby sealed. The step of crushing and the step of closing by welding may be performed simultaneously. 
     Step S 130 : Crimping Step 
     After that, the terminal  5  is crimped onto the wire  4 . The wire with terminal  3  is thereby produced. 
     The first embodiment is described above. The above-described first embodiment has the following features. 
     As shown in  FIG. 4 , the wire  4  includes the core wire  6  and the insulation coating  7  that covers the outer periphery of the core wire  6 . The core wire  6  includes the distal end region  9  containing the distal end surface  11  of the core wire  6 , and the body region  10 , which is a part other than the distal end region  9 . The distal end region  9  includes the first distal end region  12  containing the distal end surface  11 , and the second distal end region  13  located between the first distal end region  12  and the body region  10 . The insulation coating  7  includes the distal end coating part  15  that covers the outer periphery of the first distal end region  12  in a tube shape, the insulation coating body  16  that covers the outer periphery of the body region  10  in a tube shape, the coating joint part  17  that joins the distal end coating part  15  and the insulation coating body  16  together in such a way that at least part of the outer periphery of the second distal end region  13  is exposed, and the coating extension part  18  that extends from the distal end coating part  15  beyond the distal end surface  11  in a tube shape. This structure is capable of effectively sealing the distal end surface  11  by using the coating extension part  18  as well as preventing the distal end coating part  15  from coming off the core wire  6  by the presence of the coating joint part  17 . 
     Note that, if sebum on a worker&#39;s finger or the like is attached to the distal end surface  11  of the core wire  6 , there is a possibility that the properties of the distal end surface  11  change, or a sealing material  67  is difficult to be attached to the distal end surface  11 . In the above-described structure, however, a worker&#39;s finger is not likely to directly touch the distal end surface  11  of the core wire  6  because of the presence of the coating extension part  18 , which effectively prevents sebum on a worker&#39;s finger or the like from being attached to the distal end surface  11  of the core wire  6 . 
     Further, as shown in  FIG. 5 , the thickness  17 T of the coating joint part  17  in the radial direction is smaller than the thickness  20 T which corresponds to the maximum thickness of the insulation coating body  16  in the radial direction. Thus, when crimping the wire  5  onto the second distal end region  13 , it is likely that the coating joint part  17  is spread out in the width direction in the terminal  5 , which can inhibit contact between the second distal end region  13  and the wire  5 . On the other hand, in the above-described structure, the cross-section of the coating joint part  17  is small as shown in  FIGS. 13 and 14 , and therefore the coating joint part  17  is not easily spread out in the width direction. The degree of inhibiting contact between the second distal end region  13  and the wire  5  is thereby reduced, which improves the contact reliability between the second distal end region  13  and the wire  5 . 
     Further, as shown in  FIG. 4 , the insulation coating body  16  includes the first body part  19  that touches the coating joint part  17 , and the second body part  20  that is farther from the distal end surface  11  than the first body part  19  is. As shown in  FIG. 5 , the thickness  19 T of the first body part  19  in the radial direction is the same as the thickness  17 T of the coating joint part  17  in the radial direction. The thickness  20 T of the second body part  20  in the radial direction is greater than the thickness  19 T of the first body part  19  in the radial direction. In this structure, a difference between the outer diameter of the second distal end region  13  and the outer diameter of the first body part  19  is small, and accordingly a difference in level between the second distal end region  13  and the first body part  19  is small, which improves airtightness between the second distal end region  13  and the terminal  5 . 
     Further, as shown in  FIG. 4 , the welded part  21  that is crushed in the vertical direction (a cross direction crossing the longitudinal direction of the wire  4 ) and closed by welding is formed in the coating extension part  18 . In this structure, the distal end surface  11  is reliably sealed. 
     Further, as shown in  FIG. 6 , when viewing in the wire direction (in the longitudinal direction of the wire), the center of gravity  21 G of the cross-section of the welded part  21  orthogonal to the wire direction and the center of gravity  15 G of the cross-section of the distal end coating part  15  orthogonal to the wire direction do not coincide. In this manner, since the welded part  21  is asymmetric with respect to the central axis  6 C, the current position of the coating joint part  17  in the circumferential direction is identifiable by detecting the current position of the welded part  21  in the circumferential direction. If the current position of the coating joint part  17  in the circumferential direction is identifiable, the position of the coating joint part  17  in the circumferential direction is freely adjustable when crimping the terminal  5  onto the wire  4 . 
     Further, as shown in  FIG. 6 , when viewing in the wire direction (in the longitudinal direction of the wire), the center of gravity  21 G of the cross-section of the welded part  21  orthogonal to the wire direction and the center of gravity  15 G of the cross-section of the distal end coating part  15  orthogonal to the wire direction do not coincide. In this manner, when the welded part  21  is asymmetric with respect to the central axis  6 C, the current position of the welded part  21  in the circumferential direction is easily recognizable based on the position of the coating joint part  17  in the circumferential direction. 
     Further, as shown in  FIG. 4 , the welded part  21  is formed to avoid the virtual extension line  6 D of the central axis  6 C of the core wire  6 . In this structure, the retainer insertion space  47  shown in  FIG. 15  is effectively provided. 
     Further, as shown in  FIG. 6 , the cross-sectional shape of the welded part  21  orthogonal to the wire direction is a track shape. This structure allows a welding jig of the welded part  21  to have a simple structure. 
     Further, as shown in  FIG. 4 , when forming the welded part  21  in the coating extension part  18 , the direction of crushing the coating extension part  18  is preferably the vertical direction orthogonal to the wire direction. Note that, however, the coating extension part  18  may be crushed in the direction obliquely intersecting the wire direction. 
     Further, as shown in  FIG. 2 , the wire with terminal  3  includes the above-described wire  4 , and the terminal  5  attached to the wire  4 . As shown in  FIG. 7 , the terminal  5  includes the electrical contact part  27  that is capable of coming into electrical contact with a mating terminal, the wire crimp part  25  to be crimped onto the wire  4 , and the terminal joint part  26  that joins the electrical contact part  27  and the wire crimp part  25  together. The wire crimp part  25  includes two crimp pieces  29 . As shown in  FIG. 11 , each crimp piece  29  is crimped onto the distal end coating part  15 , the core wire exposure part  23  (the second distal end region  13 ) and the insulation coating body  16 , and thereby the core wire exposure part  23  (the second distal end region  13 ) is sealed. 
     Further, as shown in  FIG. 16 , when viewing the wire crimp part  25  from the electrical contact part  27  in the longitudinal direction of the wire  4 , the center of gravity  21 G of the cross-section of the welded part  21  orthogonal to the longitudinal direction of the wire  4  is located between the center of gravity  15 G of the cross-section of the distal end coating part  15  orthogonal to the longitudinal direction of the wire  4  and the terminal joint part  26 . In this structure, as shown in  FIG. 18 , the retainer insertion space  47  is effectively provided. 
     Further, as shown in  FIG. 1 , the harness  1  includes the wire with terminal  3 , and the housing  2  that accommodates the wire with terminal  3 . As shown in  FIG. 18 , the housing  2  includes the retainer  52  that is capable of coming into contact with the rear end  36 B of the spring protector  36  of the electrical contact part  27  in the wire direction. 
     Further, as shown in  FIGS. 20A and 20B , a manufacturing method for the wire  4  includes the exposing step (S 100 ) of exposing at least part of the core wire  6  by making the core wire exposure hole  60  (hole) in the insulation coating  7  that covers the core wire  6 , and the stretching step (S 110 ) of stretching the insulation coating  7  in such a way that the insulation coating  7  extends beyond the distal end surface  11  of the core wire  6 . This method is capable of forming the coating extension part  18  suitable for sealing the distal end surface  11  of the core wire  6  as well as preventing the distal end coating part  15  from coming off the core wire  6 . 
     Further, as shown in  FIG. 19 , the stretching step (S 110 ) is performed after the exposing step (S 100 ). As shown in  FIGS. 20A and 20B , in the stretching step (S 110 ), the insulation coating  7  is stretched in such a way that the opening area of the core wire exposure hole  60  made in the exposing step (S 100 ) is enlarged. This method is capable of making the coating joint part  17  thinner than that before stretching 
     Further, as shown in  FIGS. 20A and 20B , the manufacturing method for the wire  4  further includes the step (S 120 ) of crushing the coating extension part  18 , which is a part of the insulation coating  7  extending beyond the distal end surface  11  of the core wire  6 , in the cross direction crossing the longitudinal direction of the core wire  6 , and the step (S 120 ) of closing the crushed part by welding. This method is capable of sealing the distal end surface  11  at low cost. 
     Second Embodiment 
     A second embodiment is described hereinafter with reference to  FIGS. 22 to 23D . Hereinafter, differences from the above-described first embodiment are mainly described, and redundant description is omitted. FIG.  22  is a flowchart of a manufacturing method for the wire with terminal  3 .  FIGS. 23A to 23D  are views illustrating each step of the manufacturing method for the wire with terminal  3 . 
     This embodiment is different from the above-described first embodiment in the manufacturing method for the wire with terminal  3 . 
     Specifically, in the above-described first embodiment, as shown in  FIG. 19 , the exposing step (S 100 ) is performed first, and the stretching step (S 110 ) is performed after that. On the other hand, in this embodiment, a stretching step (S 200 ) is performed first, and an exposing step (S 210 ) is performed after that. The specific description is as follows. 
     Step S 200 : Stretching Step 
     First, as shown in  FIGS. 23A and 23B , the insulation coating  7  is stretched in the distal end direction in such a way that the insulation coating  7  extends beyond the distal end surface  11 . As a result, as shown in  FIG. 23B , the coating extension part  18 , which is a part of the insulation coating  7  extending beyond the distal end surface  11 , is formed. 
     Step S 210 : Exposing Step 
     Next, as shown in  FIG. 23C , the insulation coating  7  is cut at a position toward the rear end direction relative to the distal end surface  11  of the core wire  6 , and thereby the core wire exposure hole  60  is made in the insulation coating  7 . To be specific, the core wire exposure hole  60  is made in a part that has become thinner than before stretching as a result of having been stretched in the stretching step (S 200 ). The coating joint part  17  is thereby formed, and the core wire exposure part  23  is also made. 
     Step S 220 : Sealing Step 
     Then, as shown in  FIG. 23D , the coating extension part  18  is crushed in the vertical direction, and the crushed part is closed by welding, and thereby the welded part  21  is formed in the coating extension part  18 . The distal end surface  11  is thereby sealed. 
     Step S 230 : Crimping Step 
     After that, the terminal  5  is crimped onto the wire  4 . The wire with terminal  3  is thereby produced. 
     In this manner, the stretching step and the exposing step may be interchanged. 
     In this embodiment, as described above, the exposing step is performed after the stretching step, and, in the exposing step (S 210 ), the core wire exposure hole  60  is made in a part that has become thinner than before stretching as a result of having been stretched in the stretching step (S 200 ). This method is capable of making the coating joint part  17  thin in a simple process. 
     Third Embodiment 
     A third embodiment is described hereinafter with reference to  FIGS. 24 to 25D . Hereinafter, differences from the above-described first embodiment are mainly described, and redundant description is omitted.  FIG. 24  is a flowchart of a manufacturing method for the wire with terminal  3 .  FIGS. 25A to 25D  are views illustrating each step of the manufacturing method for the wire with terminal  3 . 
     This embodiment is different from the above-described first embodiment in the manufacturing method for the wire with terminal  3 . 
     Specifically, in the above-described first embodiment, as shown in  FIG. 19 , the exposing step (S 100 ) is performed first, and the stretching step (S 110 ) is performed after that. On the other hand, this embodiment is as follows. 
     Step S 300 : Slit Cutting Step 
     First, as shown in  FIG. 25A , two first slits  65  that extend in the wire direction and separate from each other in the circumferential direction are cut in the insulation coating  7  that covers the core wire  6 . The two first slits  65  are cut at the positions away from the distal end surface  11  in the wire direction. The two first slits  65  can be cut with a cutting tool, for example. 
     Step S 310 : Stretching Step 
     Next, as shown in  FIG. 25B , the insulation coating  7  is stretched in the distal end direction in such a way that the insulation coating  7  extends beyond the distal end surface  11 . To be specific, the insulation coating  7  is stretched in such a way that the length of the two first slits  65  cut in the slit cutting step (S 300 ) in the wire direction is elongated. As a result, the coating extension part  18 , which is a part of the insulation coating  7  extending beyond the distal end surface  11 , is formed. 
     Step S 320 : Exposing Step 
     Next, as shown in  FIGS. 25B and 25C , two second slits  66  are cut to connect the corresponding ends of the two first slits  65 , and thereby the core wire exposure hole  60  is made in the insulation coating  7 . The coating joint part  17  is thereby formed, and the core wire exposure part  23  is also made. 
     Step S 330 : Sealing Step 
     Then, as shown in  FIG. 25D , the coating extension part  18  is crushed in the vertical direction, and the crushed part is closed by welding, and thereby the welded part  21  is formed in the coating extension part  18 . The distal end surface  11  is thereby sealed. 
     Step S 340 : Crimping Step 
     After that, the terminal  5  is crimped onto the wire  4 . The wire with terminal  3  is thereby produced. 
     The above-described third embodiment has the following features. 
     As shown in  FIGS. 25A , the manufacturing method for the wire  4  further includes the slit cutting step (S 300 ) of cutting, in the insulation coating  7  of the wire  4 , the two first slits  65  extending in the longitudinal direction of the core wire  6  and separating from each other in the circumferential direction. As shown in  FIG. 24 , the stretching step (S 310 ) is performed after the slit cutting step (S 300 ). The exposing step (S 320 ) is performed after the stretching step (S 310 ). In the stretching step (S 310 ), the insulation coating  7  is stretched in such a way that the length of the two first slits  65  cut in the slit cutting step (S 300 ) in the wire direction is elongated. In the exposing step (S 320 ), the two second slits  66  are cut to connect the corresponding ends of the two first slits  65 , and thereby the core wire exposure hole  60  is made in the insulation coating  7 . This method is capable of making the coating joint part  17  thin in a simple process. Further, this method is capable of making the core wire exposure hole  60  in two separate steps. 
     It should be noted that, the method may cut three or more first slits  65  instead of cutting the two first slits  65 . Likewise, the method may cut three or more second slits  66  instead of cutting the two second slits  66 . 
     Fourth Embodiment 
     A fourth embodiment is described hereinafter with reference to  FIG. 26 . Hereinafter, differences from the above-described first embodiment are mainly described, and redundant description is omitted.  FIG. 26  is an enlarged perspective view of the coating extension part  18 . 
     In the above-described first embodiment, the cross-sectional shape of the welded part  21  is a track shape as shown in  FIG. 6 . In this embodiment, on the other hand, as shown in  FIG. 26 , the cross-sectional shape of the welded part  21  is a U-shape that is convex outward in the radial direction. Further, the welded part  21  is formed to avoid the virtual extension line  6 D. Note that the cross-sectional shape of the welded part  21  may be a V-shape or an ellipse instead of a U-shape. 
     Fifth Embodiment 
     A fifth embodiment is described hereinafter with reference to  FIG. 27 . Hereinafter, differences from the above-described first embodiment are mainly described, and redundant description is omitted.  FIG. 27  is a partial front cross-sectional view of the wire  4 . 
     In the above-described first embodiment, as shown in  FIG. 4 , the distal end surface  11  of the core wire  6  is sealed by forming the welded part  21  in the coating extension part  18 . 
     On the other hand, in this embodiment, as shown in  FIG. 27 , the distal end surface  11  of the core wire  6  is sealed by filling an internal space  18 S of the coating extension part  18  with the sealing material  67 . The sealing material  67  may be an adhesive or a water repellant. Compared with the case of simply applying the sealing material  67  onto the distal end surface  11  of the core wire  6 , filling the internal space  18 S of the coating extension part  18  with the sealing material  67  is expected to have a storage effect to maintain the state where the sealing material  67  is in contact with the distal end surface  11  of the core wire  6  without coming off the distal end surface  11  of the core wire  6  due to dripping before the sealing material  67  is hardened. Further, after the sealing material  67  is hardened, this is expected to have an effect of adjusting the position of the coating extension part  18  of the core wire  6  in relation to the terminal  5  as desired at the time of crimping because the outer shape of the hardened sealing material  67  does not vary. Further, since the hardened sealing material  67  is covered with the coating extension part  18 , this is also expected to have an effect of preventing the sealing material  67  from coming off the wire  4 . 
     Further, the distal end surface  11  of the core wire  6  may be sealed by inserting a hard or soft sealing member into the internal space  18 S of the coating extension part  18  instead of filling the internal space  18 S of the coating extension part  18  with the sealing material  67 . The hard sealing member may be acrylic resin or polystyrene, for example. The soft sealing member may be polyethylene or polypropylene, for example. Compared with the case of applying or disposing the sealing material  67  onto the distal end surface  11  of the core wire  6 , inserting the sealing member into the internal space  18 S of the coating extension part  18  is expected to have an effect of stabilizing the position of the coating extension part  18  of the core wire  6  with respect to the terminal  5  at the time of crimping. 
     Sixth Embodiment 
     A sixth embodiment is described hereinafter with reference to  FIG. 28 . Hereinafter, differences from the above-described first embodiment are mainly described, and redundant description is omitted.  FIG. 28  is a partial perspective view of the wire with terminal. In  FIG. 28 , the electrical contact part  27  is shown in a simplified way. 
     In the above-described first embodiment, the wire crimp part  25  of the terminal  5  is formed in an open barrel shape as shown in  FIG. 10 . 
     On the other hand, in this embodiment, the wire crimp part  25  of the terminal  5  is formed in a tubular closed barrel shape as shown in  FIG. 28 . Then, the wire crimp part  25  is crimped onto the distal end coating part  15 , the core wire exposure part  23  (the second distal end region  13 ) and the insulation coating body  16  just like in the first embodiment, and thereby the core wire exposure part  23  (the second distal end region  13 ) is sealed. 
     The first to sixth embodiments are described above. The above-described first to sixth embodiments may be implemented in any combination. 
     Each of the above-described embodiments may be varied as follows, for example. 
     Modified Example 1 
     A modified example of the first to sixth embodiments is described hereinbelow as a modified example 1 with reference to  FIG. 29 . Hereinafter, differences of this modified example from each of the above-described embodiments are mainly described, and redundant description is omitted. For example, in  FIG. 5 , the thickness  15 T of the distal end coating part  15 , the thickness  17 T of the coating joint part  17 , the thickness  19 T of the first body part  19 , and the thickness  20 T of the second body part  20  satisfy the relationship of  15 T= 17 T= 19 T&lt; 20 T. Alternatively, they may satisfy the relationship of  17 T&lt; 15 T= 19 T= 20 T. Specifically, in the stretching step (S 110 ) of  FIG. 19 , only the coating joint part  17  of the insulation coating  7  may be stretched in the wire direction as shown in  FIG. 29 . In this case, only the coating joint part  17  is thin compared with the other parts of the insulation coating  7 . 
     Modified Example 2 
     A modified example of the first to fourth embodiments and the sixth embodiment is described hereinbelow as a modified example 2 with reference to  FIGS. 30 and 31 . Hereinafter, differences of this modified example from each of the above-described embodiments are mainly described, and redundant description is omitted. 
     For example, in the above-described first embodiment, as shown in  FIGS. 19, 20B and 20C , the welded part  21  is first formed in the coating extension part  18  and the distal end surface  11  of the core wire  6  is thereby sealed (S 120 ) by crushing the coating extension part  18  in the vertical direction and then closing the crushed part by welding, and then the terminal  4  is crimped onto the wire  5  (S 130 ). In this case, there is a possibility that when the terminal  4  is crimped onto the wire  5 , the insulation coating  7  is pushed out beyond the wire crimp part  25  in the distal end direction and bulges upward, and thereby the retainer insertion space  47  of the wire with terminal  3  shown in  FIG. 18  disappears, which makes it unable to pull the retainer  52  down to a specified locking position. 
     On the other hand, in this modified example, as shown in  FIG. 30 , the terminal  4  is first crimped onto the wire  5  (crimping step: S 420 ), and then the welded part  21  is formed in the coating extension part  18  and the distal end surface  11  of the core wire  6  is thereby sealed (sealing step: S 430 ) by crushing the coating extension part  18  in the vertical direction and then closing the crushed part by welding. In this manner, by performing the sealing step (S 430 ) after the crimping step (S 420 ), even if the insulation coating  7  is pushed out beyond the wire crimp part  25  in the distal end direction and bulges upward, because the welded part  21  is formed in the subsequent sealing step (S 430 ), the bulging part disappears, and therefore the retainer insertion space  47  of the wire with terminal  3  shown in  FIG. 18  is left with no problem, and the retainer  52  is reliably pulled down to a specified locking position. Note that an exposing step (S 400 ) and a stretching step (S 410 ) are respectively the same as the exposing step (S 100 ) and the stretching step (S 110 ) in  FIG. 19  and therefore not redundantly described. Note that, as described earlier, the exposing step (S 400 ) and the stretching step (S 410 ) may be interchanged. 
       FIG. 31  is a view showing the way the welded part  21  is formed in the coating extension part  18  after the terminal  4  is crimped onto the wire  5 . As shown in  FIG. 31 , since the coating extension part  18  is not covered with the terminal  5  even after crimping, and therefore the welded part  21  is able to be formed in the coating extension part  18  after crimping by using a welding tool  70 . The welding tool  70  is made to form the welded part  21  in the coating extension part  18  by using heat or ultrasonic waves, for example. 
     The second modified example is described above with reference to  FIGS. 30 and 31 . The above-described second modified example has the following features. 
     Specifically, the manufacturing method for the wire with terminal  3  that manufactures the wire with terminal  3  by attaching the terminal  5  to the wire  4  that includes the core wire  6  and the insulation coating  7  covering the core wire  6  as shown in  FIGS. 2 and 3  includes the exposing step (S 400 ), the stretching step (S 410 ), the crimping step (S 420 ) and the sealing step (S 430 ) as shown in  FIG. 30 . 
     In the exposing step (S 400 ), at least part of the core wire  6  is exposed by making the core wire exposure hole  60  (hole) in the insulation coating  7  as shown in  FIG. 20A , for example. 
     In the stretching step (S 410 ), the insulation coating  7  is stretched in such a way that the insulation coating  7  extends beyond the distal end surface  11  of the core wire  6  as shown in  FIG. 20B , for example. 
     In the crimping step (S 420 ), the crimp piece  29  of the terminal  5  is crimped onto the wire  4  so as to seal the core wire exposure part  23  where the core wire  6  is exposed as shown in  FIGS. 10 to 12 , for example. 
     The sealing step (S 430 ) is performed after the crimping step (S 420 ). In the sealing step (S 430 ), the distal end surface  11  of the core wire  6  is sealed by welding the coating extension part  18 , which is a part of the insulation coating  7  extending beyond the distal end surface  11  of the core wire  6 , as shown in  FIG. 31 , for example. 
     According to the above-described manufacturing method, the welded part  21  is formed after crimping, and therefore the retainer insertion space  47  is reliably left above the welded part  21 . This allows the retainer  52  to be reliably pulled down to a specified locking position. 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2018-037952 filed on Mar. 2, 2018, the disclosure of which is incorporated herein in its entirety by reference.