Patent Publication Number: US-2016240937-A1

Title: Crimping terminal

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of PCT Application No. PCT/JP2014/079044, filed on Oct. 31, 2014, and claims the priority of Japanese Patent Application No. 2013-229135, filed on Nov. 5, 2013, the content of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a crimping terminal to be connected to a wire. 
     2. Related Art 
     A conventional crimping terminal of this type includes the one disclosed in JP 2009-123623 A. As shown in  FIGS. 1 and 2 , a wire W to be connected to a crimping terminal  110  includes a core wire  101  formed of a plurality of element wires  101   a  and an insulation sheath  102  covering the periphery of the core wire  101 . The insulation sheath  102  is removed at the distal end side of the wire W so as to expose the core wire  101 . 
     The crimping terminal  110  has a mating terminal connection portion  111  and a wire connection portion  115 . The wire connection portion  115  has a core wire crimping portion  116  and a sheath crimping portion  117 . The core wire crimping portion  116  has a bottom portion  116   a  and a pair of swage pieces  116   b  extended from both sides of the bottom portion  116   a.  Three long grooves (serrations)  118  are formed on the inner surface of the bottom portion  116   a  and the pair of swage pieces  116   b  of the core wire crimping portion  116 . The sheath crimping portion  117  has a bottom portion  117   a  and a pair of swage pieces  117   b  extended from both sides of the bottom portion  117   a.    
     The crimping terminal  110  swages and crimps the exposed core wire  101  with the core wire crimping portion  116  and swages and crimps the insulation sheath  102  with the sheath crimping portion  117 . 
     Meanwhile, a wire crimper  120  as shown in  FIGS. 3A and 3B  is used to swage and crimp the core wire crimping portion  116 . The wire crimper  120  has a swage groove  121  having a final swage periphery shape on its distal end side for the swage. As shown in  FIGS. 4A and 4B , the pair of swage pieces  116   b  is pressed by the wire crimper  120  to perform plastic deformation of the pair of the swage pieces  116   b.    
     SUMMARY OF THE PRESENT INVENTION 
     As shown in  FIG. 4A , the distal end side of the swage piece  116   b  bite into the core wire  101  at the center portion E 1  of the core wire crimping portion  116  in the above swaging process of the core wire crimping portion  116 , so that a large compression force acts on the center portion E 1 . However, a large compression force does not act on a portion outside the center portion E 1  of the core wire crimping portion  116 . Consequently, a large compression force does not act in a wide range, which cannot generate adhesion in a large range. 
     Furthermore, as shown in  FIG. 4B , the core wire  101  can freely stretch in the right and left axis directions (direction of arrow a, direction of arrow b) in the swaging process of the core wire crimping portion  116 . Typically, the core wire  101  located on the distal end side of the swage piece  116   b  stretches on the distal end side (direction of arrow a), and the core wire  101  located on the rear end side (insulation sheath side) of the swage piece  116   b  stretches on the rear end side (insulation sheath side) (direction of arrow b). 
     In this manner, the core wire  101  is free to stretch to reduce its diameter, so that crimping force does not effectively act on each element wire  101   a  of the core wire  101 . The element wire  101   a  generates a new surface by the stretch but only receives a low pressing force, failing to effectively generate adhesion. Such shortages of the adhesion fails to improve the conductive properties between the element wires  101   a,  disadvantageously increasing the electrical resistance of the electrical connection portion. 
     Therefore, the present invention was made to solve the above problems, and an object of the present invention is to provide a crimping terminal capable of reducing the electrical resistance of an electrical connection portion at which a wire is connected. 
     A crimping terminal according to one aspect of the present invention includes a core wire crimping portion for crimping a core wire, the core wire being formed of a plurality of element wires. The core wire crimping portion has a bottom portion, and a swage piece extended from a side of the bottom portion. The core wire crimping portion is provided with a plurality of protrusions configured to penetrate into the core wire. 
     The plurality of the protrusions may be symmetrically provided when the core wire is crimped with the core wire crimping portion. A serration may be formed on the inner surface of the core wire crimping portion. The plurality of the protrusions may include at least a pair of protrusions aligned at a height position differing from a height position of the other protrusions. 
     The crimping terminal according to one aspect of the present invention, the distal end side of the swage piece bites into the core wire at the center portion of the core wire crimping portion, so that a large compression force acts on the center portion in the process of swaging the core wire crimping portion. At this time, a large compression force acts on, via the protrusion, a portion of the core wire crimping portion outside the center portion and below the protrusion. In this manner, a large compression force can act on the core wire in a wide range of the core wire crimping portion. Furthermore, a crimping force acts on the core wire in the process of swaging the core wire crimping portion, which stretches each element wire, generating a new surface. However, the protrusion bites into the core wire, which suppresses the stretch of the core wire by the catching resistance of the protrusion, allowing the compression force to efficiently act on the core wire. That is, a new surface generates due to stretch of each element wire and the compression force efficiently acts on each element wire in a wide range, which generates adhesion, improving the conductive properties between the element wires. This reduces the electrical resistance of the electrical connection portion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a conventional example and is a perspective view of a crimping terminal before a wire is crimped thereby; 
         FIG. 2  illustrates the conventional example and is a side view of the crimping terminal by which the wire is crimped; 
         FIG. 3A  illustrates a front view of a swaging jig for the conventional example; 
         FIG. 3B  illustrates a side view of the swaging jig for the conventional example; 
         FIG. 4A  illustrates a cross sectional view illustrating a swaging process by the swaging jig for the conventional example; 
         FIG. 4B  illustrates a side view illustrating the swaging process by the swaging jig for the conventional example; 
         FIG. 5  illustrates an embodiment of the present invention, and is a perspective view of a crimping terminal before a wire is crimped thereby; 
         FIG. 6A  illustrates a side view of the crimping terminal according to the embodiment of the present invention by which the wire is crimpled; 
         FIG. 6B  illustrates a cross sectional view taken along line VIb-VIb of  FIG. 6A ; 
         FIG. 7  illustrates the embodiment of the present invention, and is a perspective view of a swaging jig; 
         FIG. 8  illustrates the embodiment of the present invention, and is a side view illustrating a swaging process by the swaging jig; 
         FIG. 9A  illustrates is a side view of a core wire crimping portion according to a first variation of the embodiment of the present invention; and 
         FIG. 9B  illustrates a side view of a core wire crimping portion according to a second variation of the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an embodiment of the present invention will be described based on the drawings. 
       FIGS. 5 to 8  illustrate the embodiment of the present invention. As shown in  FIGS. 5 to 6B , a wire W includes a core wire  1  formed of a plurality of element wires  1   a,  and an insulation sheath  2  covering the periphery of the core wire  1 . The insulation sheath  2  is removed at the distal end side of the wire W so as to expose the core wire  1 . The core wire  1  is formed of a number of the element wires  1   a  made of aluminum or aluminum alloy (hereinafter, referred to as aluminum), and a number of the element wires  1   a  are twisted each other. That is, the wire W is an aluminum wire. 
     A crimping terminal  10  is made of copper alloy, and is formed by subjecting a plate cut into a predetermined shape to a bending processing. The crimping terminal  10  has a mating terminal connection portion  11  and a wire connection portion  15 . The wire connection portion  15  has a core wire crimping portion  16  and a sheath crimping portion  17 . The core wire crimping portion  16  has a bottom portion  16   a  and a pair of swage pieces  16   b  extended from both sides of the bottom portion  16   a.    
     A number of serrations  18  having a round groove shape are formed on the inner surface of the bottom portion  16   a  and the pair of swage pieces  16   b  of the core wire crimping portion  16 . Furthermore, protrusions  19  are provided at portions, which are to be left and right side walls of the core wire crimping portion  16  after the core wire is crimped, by cut and raise. The pair of protrusions  19  protrudes toward the space on the side on which the core wire  1  is swaged (inner surface direction of the core wire crimping portion  16  in which the core wire is arranged), and sticks and penetrates into the core wire  1  at the time of crimping the core wire. The pair of protrusions  19  is symmetrically provided. Each protrusion  19  is formed such that its distal end has an edge shape (shape having a thickness reduced toward its distal end). 
     The sheath crimping portion  17  has a bottom portion  17   a  and a pair of swage pieces  17   b  extended from both sides of the bottom portion  17   a.    
     The crimping terminal  10  swages and crimps the exposed core wire  1  with the core wire crimping portion  16 , and swages and crimps the insulation sheath  2  with the sheath crimping portion  17 . 
     The crimping terminal  10  is crimped by a swaging jig  20  shown in  FIG. 7 . The swaging jig  20  has a swage groove  21  having a final swage periphery shape on its distal end side for swage. As shown in  FIG. 8 , when the pair of swage pieces  16   b  is pressed from the upper direction by the swaging jig  20 , the pair of swage pieces  16   b  is plastically deformed along the swage groove  21 . 
     As shown in  FIG. 6B , the distal end sides of the swage pieces  16   b  bite into the core wire  1  at a center portion E 1  of the core wire crimping portion  16 , so that a large compression force acts on the center portion E 1  in the swaging process of the core wire crimping portion  16 . Furthermore, a large compression force acts on, via the protrusion  19 , a portion E 2  outside the center portion E 1  of the core wire crimping portion  16  and below the protrusion  19  (portion sandwiched by a portion that becomes the bottom portion of the core wire crimping portion  16  after the core wire is crimped and the protrusion  19 ). Consequently, a large compression force acts on the core wire  1  in a wide range. 
     Furthermore, a crimping force acts on the core wire  1  in the swaging process of the core wire crimping portion  16 , so that each element wire  1   a  stretches to generate a new surface. However, the protrusion  19  penetrates into the core wire  1  arranged in the core wire crimping portion  16 , which suppresses the stretch of the core wire  1  in the axis directions (arrow a direction and arrow b direction in  FIG. 8 ) due to the catching resistance of the protrusion  19 , allowing the compression force to efficiently acts on the core wire  1 . That is, the stretch of each element wire  1   a  generates a new surface and the compression force efficiently acts on each element wire  1   a  in a wide range, which generates adhesion, improving the conductive properties between the element wires  1   a.  This reduces the electrical resistance of the electrical connection portion. 
     Serrations  18  are provided on the inner surface of the core wire crimping portion  16 . The element wire  1   a  of the core wire  1  is deformed, that is stretched and deformed, to penetrate into the serration  18 , so that a new surface is generated, which generates adhesion by receiving a compression force, reducing the conductive resistance between the core wire  1  and the core wire crimping portion  16  and also reducing the conductive resistance between the element wires  1   a.  This can also reduce the electrical resistance of the electrical connection portion. 
     The protrusions  19  are symmetrically provided when the core wire is crimped with the core wire crimping portion  16 . Thus, the element wires  1   a  of the core wire  1  can be suppressed to stretch symmetrically, allowing the core wire  1  to be crimped with excellent horizontal balance. 
     The distal end of the protrusion  19  has the edge shape, so that the protrusion  19  smoothly penetrates into the core wire  1  without bending. Consequently, the electrical resistance of the electrical connection portion due to the protrusion  19  can be stably reduced. 
     The protrusions  19  are cut and raised at portions that become left and right side walls of the core wire crimping portions  16  after the core wire is crimped. This allows obtaining a stiffening effect of the electrical connection portion, enabling to stably reduce the electrical resistance. 
     The core wire  1  is made of aluminum. The element wire  1   a  made of aluminum has an oxide layer thicker than that of the element wire made of copper alloy. Thus, increase of the electrical resistance due to the conductive resistance between element wires  1   a  was a problem in the core wire  1  made of aluminum. However, the crimping terminal according to the embodiment of the present invention is particularly effective for an aluminum wire, because the conductive resistance between the element wires  1   a  can be reduced by generation of adhesion. Although the core wire  1  made of aluminum is soft and readily stretched as compared with that made of copper alloy, the stretch of the core wire  1  in the core wire crimping portion  16  can be suppressed to generate adhesion as described above, so that the present embodiment is especially effective for an aluminum wire also from this view point. 
     (Variations) 
       FIG. 9A  illustrates a first variation of the core wire crimping portion  16 . In the first variation, three protrusions  19  are cut and raised at each of portions that become right and left side walls of the core wire crimping portion  16  after the core wire is crimped. The three protrusions  19  are aligned at the same height. 
       FIG. 9B  illustrates a second variation of the core wire crimping portion  16 . In the second variation, similarly to the first variation, three protrusions  19  are out and raised at each of portions that become right and left side walls of the core wire crimping portion  16  after the core wire is crimped. Among the three protrusions  19 , the one arranged at the center is provided at the position lower by one step than those arranged at the left and right positions. 
     Similarly to the above embodiment, the first end second variations can also suppress the stretch of the core wire  1  to allow the compression force to efficiently act on the core wire  1 . Therefore, the stretch of each element wire  1   a  generates a new surface and the compression force efficiently acts on each element wire  1   a  in a wide range, which generates adhesion, improving the conductive properties between the element wires  1   a.  This reduces the electrical resistance of the electrical connection portion. 
     Arrangement pattern, size, the number, and the like of the protrusions  19  are determined in consideration of the catching resistance of the protrusion  19  and the like (suppressing effect of the stretch of each element wire  1   a,  and the like). 
     Although the serration  18  is a groove in the embodiment, the serration  18  may be a convexity, or the serrations  18  may include both of a groove and a convexity That is, the serration denotes a groove or a convexity formed on the surface in the description. 
     Although the core wire  1  is made of aluminum in the embodiment, the core wire  1  made of a material other than aluminum (for example, made of copper alloy) can also be applied to the present invention. 
     Although the embodiment of the present invention has been described heretofore, the embodiment is merely exemplified for facilitating the understanding of the present invention, and the present invention is not limited to the embodiment. The technical scope of the present invention may include not only the specific technical matters disclosed in the above-described embodiment but also various modifications, changes, and alternative techniques easily derived from the above-described specific technical matters.