Patent Publication Number: US-9847586-B2

Title: Metal terminal fitting crimped to a folded end portion of a braided wire

Description:
This application claims the benefit of Japanese Application No. JP2016-025565, filed on Feb. 15, 2016, the contents of which are hereby incorporated by reference in their entirety. 
     FIELD 
     The present invention relates to an electrical wire with a terminal fitting and a method of manufacturing the electrical wire with a terminal fitting. 
     BACKGROUND 
     Conventionally, an electrical wire with a terminal fitting is known in which a terminal fitting is crimped to the end portion of a braided wire. The braided wire is formed by braiding a large number of metal strands, and is cut to a predetermined length. One end portion of the braided wire is set in a barrel portion of the terminal fitting, and then barrel pieces are crimped. 
     Incidentally, the strands in the end portion of the braided wire easily become loose and spread apart. When the strands in the end portion of the braided wire become loose, the tensile strength can decrease due to the strands becoming pinched between the barrel pieces of the terminal fitting, and concerns arise such as the contact resistance becoming unstable when the strands spread apart in the braided wire. In view of this, a technique is known in which the end portion of the braided wire is provided with a crimping portion obtained by welding the strands using a resistance welder, as disclosed in JP 2015-60632A. The strands become bonded and consolidated together in the crimping portion, thus making it possible to prevent the strands from becoming loose and spreading apart. 
     However, in the configuration described above, a welding device is used in order to form the crimping portion, thus making it likely for the equipment cost to become expensive and for manufacturing cost to rise. 
     SUMMARY 
     The present design was achieved in light of the circumstances described above, and an object is to provide an electrical wire with a terminal fitting that can be manufactured without using a welding device, and a method of manufacturing this electrical wire with a terminal fitting. 
     An electrical wire with a terminal fitting according to one aspect of the present design includes: a metal foil; a braided wire; and a terminal fitting, wherein the metal foil is wrapped around an end portion of the braided wire, and the terminal fitting is connected to an outer side of the wrapped metal foil. 
     A method of manufacturing an electrical wire with a terminal fitting according to one aspect of the present design includes: a cutting step of cutting a braided wire; a wrapping step of wrapping a metal foil around the braided wire; and a terminal connection step of connecting the terminal fitting to an end portion of the braided wire that is wrapped with the metal foil. 
     According to the present design, the loosening and spreading apart of strands in the end portion of the braided wire can be prevented by the metal foil, thus making it possible to manufacture the electrical wire with a terminal fitting without using a welding device. 
    
    
     
       DRAWINGS 
         FIG. 1  is a plan view of an electrical wire with a terminal fitting according to a first embodiment; 
         FIG. 2  is a cross-sectional view of a state in which a barrel portion has been crimped to an end portion of a braided wire, and is a cross-sectional view that corresponds to a cross section taken at position A-A in  FIG. 1 ; and 
         FIGS. 3A to 3D  are schematic views of the end portion of the braided wire in some steps for manufacturing the electrical wire with a terminal fitting, where  FIG. 3A  is a schematic view of a state after cutting,  FIG. 3B  is a schematic view of the folding over of a group of strands,  FIG. 3C  is a schematic view of the folded over state, and  FIG. 3D  is a schematic view of a state in which metal foil has been wrapped around the end portion. 
     
    
    
     DESCRIPTION 
     Preferred embodiments will be described below. 
     In the electrical wire with a terminal fitting according to another aspect of the present design, an end portion of the braided wire may be folded over onto itself. 
     In the method of manufacturing an electrical wire with a terminal fitting according to another aspect of the present design, the wrapping step of wrapping the metal foil around the end portion of the braided wire may be performed after the cutting step. According to this method, the braided wire is cut in a state of not being wrapped with the metal foil, thus making it possible to cut the braided wire more easily than in the case of cutting a portion that is wrapped with the metal foil. 
     In the method of manufacturing an electrical wire with a terminal fitting according to another aspect of the present design, in the wrapping step, the metal foil may be wrapped around a cutting target portion of the braided wire, and in the cutting step performed thereafter, the cutting target portion may be cut in a state of being wrapped with the metal foil. According to this method, it is possible to improve productivity through the use of an automatic machine. 
     Also, in the method of manufacturing an electrical wire with a terminal fitting according to another aspect of the present design, a folding step of folding over the end portion of the braided wire onto itself may be performed after the cutting step. According to this method, the braided wire is cut in the state of not being folded over (the state in which the thickness is smaller than that of the braided wire when folded), thus making it possible to easily cut the braided wire. 
     First Embodiment 
     Hereinafter, a first embodiment of the present design will be described in detail with reference to  FIGS. 1 to 3D . 
     An electrical wire with a terminal fitting  10  of the present embodiment includes a braided wire  11  and a pair of terminal fittings  12  that are connected to the two lengthwise end portions of the braided wire  11 . 
     The terminal fittings  12  are each formed by performing presswork on a plate material that is made of a metal that has excellent electrical conductivity (e.g., a copper alloy). The terminal fittings  12  each have a connection portion  13  for connection to a device or the like, and a barrel portion  14  for connection to an end portion of the braided wire  11 , and the connection portion  13  and the barrel portion  14  are integrated with each other. A through-hole  15 , into which a fastening member (not shown) such as a bolt can be inserted, is formed in the connection portion  13  and passes through the connection portion  13  in the plate thickness direction. The through-hole  15  is an elongated hole that is elongated in the lengthwise direction of the braided wire  11 . 
     The barrel portion  14  includes a bottom plate  16  that extends in one direction from the connection portion  13  and is flush with the same, and a pair of barrel pieces  17  that extend from the two widthwise side edges of the bottom plate  16 . The terminal fitting  12  is connected to the end portion of the braided wire  11  by crimping the pair of barrel pieces  17  to the end portion of the braided wire  11 . 
     The braided wire  11  is tubular, and is formed by multiple (approximately 6,000 in the present embodiment) highly electrically conductive metal strands being braided into a mesh (net). The braided wire  11  has favorable flexibility. The metal strands are made of a copper-based metal, and are plated with tin on the surface. The end faces of the braided wire  11  are cut faces. 
     The end portions of the braided wire  11  are each folded over onto itself in the width direction. As shown in  FIG. 3B , each end portion of the braided wire  11  is folded in two at the center of the width direction and laid on itself to form two layers. Accordingly, the end portion of the braided wire  11  has half the width of an intermediate portion in the lengthwise direction of the braided wire  11 , and twice the thickness thereof. 
     As shown in  FIG. 3D , a piece of metal foil  18  is wrapped around the end portion of the braided wire  11 . 
     The metal foil  18  is adhesive copper foil for example, and an electrically conductive adhesive or the like has been applied to either the upper or lower surface. 
     The metal foil  18  is obtained by cutting metallic tape, which is elongated in one direction, to a predetermined length. 
     The metal foil  18  has a length according to which it can encompass at least the entire outer circumference of the end portion of the braided wire  11 . The metal foil  18  has a width according to which it can encompass a predetermined range in the lengthwise direction from the cut face of the braided wire  11 . 
     The metal foil  18  is wrapped around the end portion of the braided wire  11  that has been folded over. Portions of the inner surface of the folded-over braided wire  11  are in contact with each other. 
     Next, one example of a method of manufacturing the electrical wire with a terminal fitting  10  of the present embodiment will be described. 
     First, a cutting step is performed in which the braided wire  11  is cut. The cutting step is performed in the state in which the braided wire  11  is not folded over in the width direction (the state in which the braided wire  11  is spread out flat in the width direction). The braided wire  11  is cut at a predetermined position by a cutter device (not shown), thus giving the braided wire  11  a predetermined length. As shown in  FIG. 3A , the strands easily become loose and spread apart in the end portion of the cut braided wire  11 . 
     Next, a folding step is performed in which the end portion of the cut braided wire  11  is folded over onto itself. As shown in  FIG. 3B , the end portion of the braided wire  11  is folded in two at the center in the width direction and laid on itself while keeping the loosened strands in a group. 
     Next, a wrapping step is performed in which the metal foil  18  is wrapped around the end portion of the braided wire  11 . As shown in  FIG. 3D , the metal foil  18 , which has been cut to a predetermined length, is wrapped around and adhered to the entire circumference of the end portion of the braided wire  11 . The wrapping step of wrapping the metal foil  18  is performed manually. In the end portion of the braided wire  11  that is wrapped with the metal foil  18 , the strands are held in a grouped state and are not loose. In the present embodiment, the folding step and the wrapping step are performed in the stated order on each of the two ends of the braided wires  11 . 
     Next, a terminal connection step is performed in which the terminal fitting  12  is connected to the end portion of the braided wire  11 . The end portion of the braided wire  11  is set inside the barrel portion  14 . The entirety of the portion of the end portion of the braided wire  11  that is wrapped with the metal foil  18  is arranged inside the barrel portion  14 . Either the upper or lower surface of the end portion of the braided wire  11  is placed on the bottom plate  16 , one end of the braided wire  11  in the width direction is positioned at the base of one of the barrel pieces  17 , and the other end is placed at the base of the other barrel piece  17 . When the barrel portion  14  is pressed by a crimping device (not shown), the leading ends of the pair of barrel pieces  17  abut against each as shown in  FIG. 2 , and thus the barrel portion  14  encompasses and is crimped to the end portion of the braided wire  11 . The end portion of the braided wire  11  in the folded over state is crimped by the barrel portion  14 , and therefore portions of the inner side of the braided wire  11  come into close contact with each other. In the present embodiment, the terminal connection step is performed in the stated order on each of the two end portions of the braided wire  11 . 
     The manufacturing of the electrical wire with a terminal fitting  10  is thus complete. 
     Next, actions and effects of the present embodiment having the above configuration will be described. 
     In the electrical wire with a terminal fitting  10  of the present embodiment, the metal foil  18  is wrapped around the end portions of the braided wire  11 , and the terminal fittings  12  are connected to the end portions. According to this configuration, the loosening and spreading apart of strands in the end portions of the braided wire  11  can be prevented by the metal foil  18 , and this makes it possible to manufacture the electrical wire with a terminal fitting  10  without using a welding device. 
     Also, in the case where loosening in the end portions of the braided wire  11  is prevented by soldering for example, there is a concern that the solder will penetrate into the braided wire  11  and cause the braided wire  11  to harden, thus degrading the flexibility of the braided wire  11 . However, according to the present embodiment, the loosening and spreading apart of strands in the end portions of the braided wire  11  can be prevented by the metal foil  18 , thus making it possible to prevent the aforementioned situation. Furthermore, the metal foil  18  is bendable, thus making it possible to improve connection reliability between the braided wire  11  and the terminal fittings  12 . 
     Also, the cutting step of cutting the braided wire  11  is performed, and thereafter the wrapping step of wrapping the metal foil  18  around the end portion of the cut braided wire  11  is performed. According to this method, the braided wire  11  is cut in the state of not being wrapped with the metal foil  18 , thus making it possible to cut the braided wire  11  more easily than in the case of cutting a portion that is wrapped with the metal foil  18 . 
     Also, after the cutting step, the folding step is performed in which the end portion of the cut braided wire  11  is folded over onto itself in the width direction. According to this method, the braided wire  11  is cut in the state of not being folded over (the state in which the thickness is smaller than that of the braided wire  11  when folded), thus making it possible to easily cut the braided wire  11 . 
     Second Embodiment 
     Next, a method of manufacturing the electrical wire with a terminal fitting  10  according to a second embodiment of the present design will be described. 
     The method of manufacturing the electrical wire with a terminal fitting  10  according to the present embodiment is different from that of the first embodiment in that a wrapping step is performed in which the metal foil  18  is wrapped around a cutting target portion of the braided wire  11 , and thereafter a cutting step is performed in which the cutting target portion, which is wrapped with the metal foil  18 , is cut. Note that configurations similar to those in the first embodiment are denoted by the same reference signs, and redundant descriptions will not be given for them. 
     Similarly to the first embodiment, in the electrical wire with a terminal fitting  10  of the present embodiment, pieces of metal foil  18  are wrapped around the end portions of the braided wire  11 , the terminal fittings  12  are connected to the end portions, and the end portions of the braided wire  11  are each folded over onto itself in the width direction. 
     Next, one example of a method of manufacturing the electrical wire with a terminal fitting  10  of the present embodiment will be described. 
     First, a wrapping step is performed in which the metal foil  18  is wrapped around a cutting target portion of the braided wire  11 . Similarly to the first embodiment, the metal foil  18 , which has been cut to a predetermined length, is wrapped around and adhered to the entire circumference of the cutting target portion of the braided wire  11 . The wrapping step is performed in the state in which the braided wire  11  is not folded over in the width direction (the state in which the braided wire  11  is spread out flat in the width direction). 
     Next, a cutting step is performed in which the cutting target portion, which is wrapped with the metal foil  18 , is cut. The cutting target portion of the braided wire  11  is cut by a cutter device (not shown), thus giving the braided wire  11  a predetermined length. At this time, by performing cutting using a hot cutter, it is possible to increase the fixing force of the braided wire  11  and the metal foil  18 . In the end portion of the cut braided wire  11 , the strands are wrapped with the metal foil  18  and thus are held in a grouped state in which they do not become loose and spread apart. 
     Thereafter, a folding step of folding the end portion of the cut braided wire  11  over onto itself, and a terminal connection step of connecting the terminal fitting  12  to the end portion of the braided wire  11  are performed in the stated order, thus completing the manufacturing of the electrical wire with a terminal fitting  10 . The barrel portion  14  is crimped to the end portion of the braided wire  11  in the folded state, and thus portions of the metal foil  18  arranged inside the barrel portion  14  come into close contact with each other. 
     As described above, in the manufacturing method of the present embodiment, by cutting the metal foil  18  and the braided wire  11  at the same time, the spreading of the braided wire  11  after cutting can be suppressed, and it is possible to improve productivity through the use of an automatic machine, and to eliminate the need for the task of grouping together loose strands in the end portions of the braided wire  11 . 
     Other Embodiments 
     The present invention is not intended to be limited to the embodiments described using the above descriptions and drawings, and embodiments such as the following examples are also encompassed in the technical scope of the present invention. 
     Although specific examples of the terminal fittings  12  connected to the two end portions of the braided wire  11  are described in the above embodiments, the present invention is not limited to these examples, and various types of terminal fittings can be used. 
     Although the end portions of the braided wire  11  are folded in two in the above embodiments, the present invention is not limited to this, and the end portions of the braided wire may be folded in three or rounded for example. 
     Although the end portions of the braided wire  11  are each folded over onto itself in the above embodiments, the present invention is not limited to this, and the end portions of the braided wire may be flattened without being folded over. 
     Although the end portions of the braided wire  11  are folded in two at the center in the width direction in the above embodiments, the present invention is not limited to this, and the two widthwise edge portions of each end portion of the braided wire may be folded over toward the center. 
     Although the end portions of the braided wire  11  are folded over in the width direction in the above embodiments, the present invention is not limited to this, and the end portions of the braided wire may be folded over in the axial direction. 
     Although the wrapping step is performed after the folding step in the first embodiment, the present invention is not limited to this, and the folding step may be performed after the wrapping step. 
     Although the folding step is performed after the wrapping step in the second embodiment, the present invention is not limited to this, and the wrapping step may be performed after the folding step. 
     It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims. 
     As used in this specification and claims, the terms “for example,” “e.g.,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. 
     REFERENCE SIGNS LIST 
       10 : Electrical wire with a terminal fitting 
       11 : Braided wire 
       12 : Terminal fitting 
       18 : Metal foil