Abstract:
A wire connecting method and a wiring harness that allows one to utilize a single terminal for multiple core wires having various diameters thereby reducing the number and different types of terminals. The wire connecting method allows the larger wire cores first to be ultrasonic pressed such that the diameter of the larger core wires are reduced to sizes that are small enough to utilize the single terminal used on smaller core wires.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of International Application No. PCT/JP2011/058922filed Apr. 8, 2011, claiming priority based on Japanese Patent Application No. 2010-090524filed Apr. 9, 2010, the contents of all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     This invention relates to a wire connecting method and a wiring harness, in particular, to a wire connecting method for connecting terminals with a plurality of types of covered wire having core wire sizes different from each other, and to a wiring harness having a plurality of types of covered wire having core wire sizes different from each other, and terminals connected to the covered wires. 
     BACK GROUND ART 
     Various electronic devices are mounted on a vehicle as a moving body. A wiring harness is routed in the vehicle for supplying electric power from a power source such as a battery and a control signal from a controller to the electronic devices. The wiring harness includes: a plurality of covered wires; and terminals connected to ends of the covered wires. 
     As an example of a connecting method for connecting terminals with the ends of the covered wires, for example, a method using pressure bonding shown in  FIG. 5  is known (for example, PLT1, PLT2). As shown in  FIG. 5 , a covered wire  100  includes: a core wire  101  made by braiding a plurality of conductive element wires; and an insulating cover  102  covering the core wire  101 . The cover  102  is removed at an end of the covered wire  100  and the core wire  101  is exposed. 
     A terminal  200  is provided with a not-shown electric contact portion attached to a metallic panel of a vehicle body and connected to a mating terminal, and a wire barrel  201  for pressure-bonding the core wire  101 , arranged in a row in a longitudinal direction of the terminal  200 . The wire barrel  201  is composed of a bottom wall portion  201 A and a pair of crimping pieces  201 B extended vertically from both edges in a width direction of the bottom wall portion  201 A, and formed in a U-shape. 
     As shown in  FIGS. 6B and 6C , when the core wire  101  exposed at the end of the covered wire  100  is mounted on a bottom wall  201 A of the pair of crimping pieces  201 B of the wire barrel  201 , and the pair of crimping pieces  201 B is bent inward to crimp the core wire  101 , the terminal  200  is pressure-bonded to the core wire  101 . Incidentally, in a lower part of  FIG. 6 , the core wire  10  is omitted. 
     However, in the wire barrel  201 , there is a problem that a range of a size of the core wire  101  allowed to be pressure-bonded is small. When explaining in detail, as shown in  FIG. 6A , when a core wire size is too small with respect to a barrel length L, ends of the crimping pieces  201 B abut on the bottom wall  201 A, and the terminal  200  and the core wire  101  of the covered wire  100  are not successfully electrically connected to each other. 
     Further, as shown in  FIG. 6D , when the core wire size is too large with respect to the barrel length L, the ends of the crimping pieces  201 B are separated from each other, and the core wire  101  is unraveled from a gap therebetween, and the terminal  200  and the core wire  101  of the covered wire  100  are not successfully electrically connected to each other. 
     Therefore, conventionally, as shown in  FIG. 7 , when the terminal  200  is connected to a plurality of types of covered wires  100  having different core wire sizes, a large terminal  200 A and a small terminal  200 B having different barrel lengths are prepared. The large terminal  200 A is connected to the covered wire  100  having a large core wire size, and the small terminal  200 B is connected to the core wire  101  having a small core wire size. As a result, it is necessary to prepare a plurality of terminals  200  having different sizes corresponding to the core wire sizes, and cost may be improved. 
     Further, as a connection method for connecting the terminal  200  to the end of the covered wire  100 , a method in which a tubular crimping portion is provided by connecting ends of the pair of crimping pieces  201 B of the wire barrel  201  to each other, and the core wire  101  exposed at the end of the covered wire  100  is inserted into the tubular crimping portion and crimped, a method in which a bottom wall and a pair of press-connecting blades extended vertically from the bottom wall are provided, and the core wire  101  is inserted into the pair of press-connecting blades and press-connected and the like are also possible (PTL 3). In any case similarly, the terminals  200  having a plurality of sizes corresponding to the core wire sizes are needed, and there is a cost problem. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] 
     JP, A, 2009-231079 
     [PTL 2] 
     JP, A, 2006-108051 
     [PTL 3] 
     JP, A, H05-159628 
     SUMMARY OF INVENTION 
     Technical Problem 
     Accordingly, an object of the present invention is to provide a wire connecting method and a wiring harness allowed to reduce the number of types of terminals for reducing cost by increasing the number of core wire sizes able to be crimped or press-connected with respect to one terminal. 
     Solution to Problem 
     For attaining the object, according to the invention claimed in claim  1 , there is provided a wire connecting method for crimping or press-connecting respectively a first covered wire having a core wire size within a specific range and a second covered wire having a core wire size larger than the specific range with a terminal having a bottom wall and a pair of pieces extended vertically from the bottom wall having sizes able to be crimped or press-connected to a core wire within the specific range size comprising the steps of: 
     performing an ultrasonic processing in which while a pressure is applied to the core wire of the second covered wire, ultrasonic energy is applied to the core wire to reduce the core wire size within the specific range; and 
     mounting the core wire of the second covered wire of which core wire size is reduced within the specific range by the ultrasonic processing on the bottom wall between the pair of pieces of the terminal, and crimping or press-connecting the core wire between the pair of pieces. 
     According to the invention claimed in claim  2 , there is provided the wire connecting method as claimed in claim  1 , further comprising the step of: 
     mounting the core wire of the first covered wire on the bottom wall between the pair of pieces of the terminal without the ultrasonic processing, and crimping or press-connecting the core wire between the pair of pieces. 
     According to the invention claimed in claim  3 , there is provided a wiring harness comprising: 
     a first covered wire having a core wire size within a specific range; 
     a second covered wire having a core wire size larger than the specific range; and 
     a plurality of terminals each composed of a bottom wall and a pair of pieces extended vertically from the bottom wall, and respectively crimped or press-connected to the first and second covered wires, 
     wherein the sizes of the bottom wall and the pair of pieces of each terminal is able to be crimped or press-connected to the core wire within the specific range, and 
     wherein the core wire of the second covered wire is performed an ultrasonic processing in which while a pressure is applied to the core wire, ultrasonic energy is applied to the core wire to reduce the core wire size within the specific range, and crimped or press-connected between the pair of pieces of the terminal. 
     According to the invention claimed in claim  2 , there is provided the wiring harness as claimed in claim  3 , 
     wherein the core wire of the first covered wire is crimped or press-connected between the pair of pieces of the terminal without the ultrasonic processing. 
     Advantageous Effects of Invention 
     As explained above, according to the inventions claimed in claims  1  to  4 , the core wire size of the second covered wire is reduced by the ultrasonic processing, and the core wire of the second covered wire is crimped or press-connected to the terminal. Therefore, the core wire of the second covered wire having the core wire size larger than the specific range can be connected to the terminal able to be crimped or press-connected to the core wire within the specific range size. Accordingly, the number of the core wire sizes able to be crimped or press-connected to one terminal is increased, thereby cost can be reduced by reducing the number of types of the terminals. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view showing an embodiment of a wiring harness according to the present invention. 
         FIG. 2  is an explanatory view for explaining a wire connecting method to connect a terminal with a covered wire shown in  FIG. 1 . 
         FIG. 3  is a schematic view showing an example of an ultrasonic processing device for a core wire of the covered wire shown in  FIG. 2 . 
         FIG. 4A  is a schematic view showing another example of the ultrasonic processing device. 
         FIG. 4B  is a schematic view showing the core wire after an ultrasonic processing by the ultrasonic processing device shown in  FIG. 4A . 
         FIG. 5  is an explanatory view for explaining a conventional crimping method of a terminal. 
         FIG. 6  is an explanatory view for explaining problems of the conventional crimping method. 
         FIG. 7  is an explanatory view for explaining the conventional crimping method to crimp more than one type of the covered wires having different core wire sizes with terminals. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a wire connecting method and a wiring harness according to the present invention will be explained with reference to  FIGS. 1 to 3 . As shown in  FIG. 1 , a wiring harness  1  includes: a plurality of types of covered wires  11  to  14  having different core wire diameters (core wire sizes) R 1  to R 4 ; and a plurality of terminals  15  connected to these covered wires  11  to  14 . Each of the covered wires  11  to  14  includes: a core wire  16  made of braided conductive element wires; and an insulating cover  17  covering the core wire  16 . Incidentally, the core wire diameters R 1  to R 4  of the covered wires  11  to  14  are provided bigger in order of the covered wire  11 , the covered wire  12 , the covered wire  13 , and the covered wire  14  (namely, R 1 &lt;R 2 &lt;R 3 &lt;R 4 ). 
     The terminals  15  are formed in the same shape and in the same size. The terminal  15  is provided with a not-shown electric contact portion attached to a metallic panel of a vehicle body, or connected to a mating terminal, and a wire barrel  18  for crimping the core wire  16  of the covered wires  11  to  14  arranged in a row in a longitudinal direction of the terminal  15 . As shown in  FIG. 2 , the wire barrel  18  is composed of a bottom wall  18 A and a pair of crimping pieces  18 B extended vertically from both edges in a width direction of the bottom wall  18 A, and formed in a U-shape. 
     The wire barrel  18  of the terminal  15  has a barrel length L able to crimp the core wire  16  having a core wire diameter within a specific range including the core wire diameters R 1  and R 2 , and unable to crimp the core wire  16  having a core wire diameter R 3  or R 4  larger than the specific range because the electric connection with the core wire  16  is not good as explained in the background art. As is clear from the above, the covered wires  11 ,  12  having the core wire diameters R 1 , R 2  correspond to the first covered wire in claims, and the covered wires  13 ,  14  having the core wire diameters R 3 , R 4  correspond to the second covered wire in claims. 
     Next, a procedure for connecting the terminals  15  having the same shape and the same size with a plurality of types of covered wires  11  to  14  having different core wire diameters will be explained. First, the covers  17  at ends of the covered wires  11  to  14  are removed to expose the core wires  17 . 
     As described above, the core wire diameters of the covered wires  13 ,  14  are large in comparison with the barrel length L of the terminal  15 , and if directly crimping to the terminal  5 , the covered wires  13 ,  14  are not successfully electrically connected to the terminal  15 . So, as shown in  FIGS. 2(C) and 2(D) , an ultrasonic processing in which while the pressure is applied to the core wire  16 , ultrasonic energy is applied to the core wire  16  is performed to the covered wires  13 ,  14 . to reduce the core wire diameter within the specific range, and then the core wire  16  is crimped to the wire barrel  18  of the terminal  15 . As shown in the middle parts of  FIGS. 2(C) and 2(D) , the core wires  16  of the covered wires  13 ,  14  are made smaller so that the core wire diameters thereof are substantially equal to a core wire diameter R 1  of the covered wire  11 . 
     The above ultrasonic processing is performed by using an ultrasonic processing device  20  shown in  FIG. 3 . As shown in  FIG. 3 , the ultrasonic processing device  20  includes: a pair of box-shaped molds  21 ,  22  for pinching the core wire  16  exposed by removing the cover  17  at the end of the covered wire  13 ,  14  in a horizontal direction; and an anvil  23  and a horn  24  for pinching the core wire  16  in a vertical direction. 
     The mold  21  is provided movably in the horizontal direction along an upper face of the horn  24 . The mold  22  is provided movably in the vertical direction along a right side face of the horn  24 . The anvil  23  is mounted on an upper face of the mold  22 , and provided movably in the vertical direction along a right side face of the mold  21 . The horn  24  is fixed, and a concave-convex groove is formed on an upper face of the horn  24  along a longitudinal direction of the horn  24 . 
     The ultrasonic processing device  20  further includes: fixing members  25 ,  26  for pinching the mold  22  and the horn  24  in the horizontal direction to prevent the mold  22  and the horn  24  from moving in the horizontal direction; and a fixing member  27  abutting on a lower face of the horn  24  to prevent the horn  24  from moving in the vertical direction. A not-shown piezoelectric oscillator is attached to the horn  24 . An ultrasonic oscillation of the not-shown piezoelectric oscillator oscillates the horn  24  in the vertical direction. 
     Next, a procedure of the ultrasonic processing using the above-described ultrasonic processing device  20  will be explained. First, in the ultrasonic processing device  20 , the mold  21  is moved in the horizontal direction to adjust a width between the molds  21 ,  22  to, for example, R 1 . Then, as shown in  FIG. 3 , the core wire  16  of the covered wire  13 ,  14  is positioned between the molds  21 ,  22  and between the anvil  23  and the horn  24 . Then, the anvil  23  is moved downward to pinch the core wire  16  with the anvil  23  and the horn  24 . Then, while the pressure is applied to the core wire  16 , the not-shown piezoelectric oscillator is oscillated. Owing to the ultrasonic oscillation of the not-shown piezoelectric oscillator, the horn  24  is oscillated and the ultrasonic energy is applied to the core wire  16 . Then, the anvil  23  is further moved downward until a distance between the anvil  23  and the horn  24  becomes, for example, R 1 . 
     In this way, while the pressure is applied to the core wire  16  in the vertical direction by the anvil  23  and the horn  24 , the ultrasonic energy is applied to the core wire  16 . Owing to this pressure, the core wire  16  is expanded in the horizontal direction, and contracted in the vertical direction. As a result of the expansion of the core wire  16  in the horizontal direction, the core wire  16  abuts on the molds  21 ,  22 . Then, a contraction force is applied to the core wire  16  in the horizontal direction by the molds  21 ,  22 . Owing to this pressure, each element wire having a circular sectional shape and composing the core wire  16  is deformed to have a rectangular sectional shape. Then, the core wire  16  of the covered wire  13  having the core wire diameter R 3  is compressed to be in a rectangular sectional shape and R 1  in height and width. Similarly, the core wire  16  of the covered wire  14  having the core wire diameter R 4  is compressed to be in a rectangular sectional shape and R 1  in height and width. Incidentally, time to applying the ultrasonic energy is set up in view of time for removing an oxide layer from a surface of the core wire  16  and time for roughening the surface of the core wire  16 . 
     Then, as shown in middle parts of  FIGS. 2(C) and 2(D) , the core wire  16  compressed in a rectangular shape R 1  in height and width is mounted on the bottom wall  18 A between the pair of crimping pieces  18 B, and crimped by bending the pair of crimping pieces  18 B inward to wrap the core wire  16 . Thus, as shown in lower parts of  FIGS. 2(C) and 2(D) , the terminal  15  is crimped to be connected to the core wire  16 . Incidentally, in the lower parts of  FIG. 2  in which the wire barrel  18  is crimped, the core wire  16  is omitted. 
     In contrast, the ultrasonic processing is not performed to the covered wires  13 ,  14  having the core wire diameters R 1 , R 2 . As shown in upper parts of  FIGS. 2(A) and 2(B) , the covered wire  13 ,  14  is directly mounted on the bottom wall  18 A between the pair of crimping pieces  18 B, and crimped by bending the pair of crimping pieces  18 B inward to wrap the core wire  16 . Thus, as shown in lower parts of  FIGS. 2(A) and 2(B) , the covered wire  13 ,  14  is crimped to the wire barrel  18  of the terminal  15 . 
     According to the above embodiment, a step to reduce the core wire diameter within the specific range able to crimp with the terminal  15  by the ultrasonic processing in which while the pressure is applied to the core wire  16  of the covered wire  13 ,  14 , the ultrasonic energy is applied to the core wire  16 , a step to mount the core wire  16  of the covered wire  13 ,  14  of which core wire diameter is reduced by the ultrasonic processing on the bottom wall  18 A between the pair of crimping pieces  18 B, and to crimp the core wire  16  to the pair of crimping pieces  18 B, and a step to mount the core wire  16  of the covered wire  11 ,  12  on the bottom wall  18 A between the pair of crimping pieces  18 B without the ultrasonic processing, and to crimp the core wire  16  to the pair of crimping pieces  18 B are performed. Therefore, because the core wire diameter of the core wire  16  of the covered wire  13 ,  14  is reduced by the ultrasonic processing, and the core wire  16  is crimped to the terminal  15 , the core wire  16  of the covered wire  13 ,  14  of which core wire diameter R 3 , R 4  is larger than the specific range can be connected to the terminal  15  able to crimp the core wire  16  of which core wire diameter is within the specific range. Therefore, the number of the core wire diameters able to be crimped to the one terminal  15  is increased, thereby the number of the types of the terminals  15  can be reduced, and cost can be reduced. 
     Incidentally, in the above embodiment, the core wire diameter is R 3 , R 4  of the core wire  16  of the covered wire  13 ,  14  is reduced to R 1  by the ultrasonic processing. However, the present invention is not limited to this. The core wire diameter after the ultrasonic processing may be within the specific range able to crimp with the terminal  15 . 
     Further, in the above embodiment, as shown in  FIG. 3 , the core wire  16  is formed in a rectangular sectional shape after the ultrasonic processing using the ultrasonic processing device  20  with the box-shaped molds  21 ,  22 , the anvil  23 , and the horn  24 . However, the present invention is not limited to this. The core wire  16  may be in any sectional shape after the ultrasonic processing as long as the core wire  16  can be crimped to the terminal  15 . For example, as shown in  FIG. 4A , the core wire  16  is pinched between the anvil  23  and the horn  24  each provided with a semicircular sectional shaped groove, and while the anvil  23  is moved close to the horn  24  to apply the pressure to the core wire  16 , the ultrasonic energy is applied to the core wire  16 . Thereby, as shown in  FIG. 4B , the core wire  16  after the ultrasonic processing may be in a circular sectional shape. 
     Further, in the above embodiment, the terminal  15  having the wire barrel  18  on which the core wire  16  is mounted and crimped is used. However, the present invention is not limited to this. For example, the terminal  15  may be provided with a tubular crimping portion made by connecting ends of the pair of crimping pieces  18 B of the wire barrel  18  to each other. The core wire  16  exposed at the end of the covered wire  11  to  14  is inserted into the tubular crimping portion and crimped. Alternatively, the terminal  15  may be composed of the bottom wall and a pair of press-connecting blades. The core wire  16  is inserted into between the pair of press-connecting blades, and press-connected. 
     Further, in the above embodiment, the plurality of terminals  15  is separately provided. However, the present invention is not limited to this. For example, a joint connector terminal in which the terminals  15  are joined together may be used. 
     Further, the above embodiment only shows a representative example of the present invention. The present invention is not limited to the embodiment. Namely, various modifications can be practiced within a scope of the present invention. 
     REFERENCE SIGNS LIST 
     
         
           11  covered wire (first covered wire) 
           12  covered wire (first covered wire) 
           13  covered wire (second covered wire) 
           14  covered wire (second covered wire) 
           16  core wire 
           15  terminal 
           18 A bottom wall 
           18 B crimping piece (piece)