Patent Publication Number: US-9843120-B2

Title: Terminal metal fitting

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2015-152411 filed in Japan on Jul. 31, 2015. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a terminal metal fitting. 
     2. Description of the Related Art 
     Conventionally, terminal metal fittings formed into a predetermined shape by punching a metal plate, prepared as a base material, into a predetermined developed shape and performing a bending process and the like on the plate have been known. For example, in such a terminal metal fitting, a box shape is formed when a plurality of portions of a certain part in its developed shape are bent in the same direction. The box body is then used as a terminal connecting body that is electrically connected to a counterpart terminal (refer to, for example, Japanese Patent Application Laid-open No. 2004-31034, Japanese Patent Application Laid-open No. 2005-5109, and Japanese Patent Application Laid-open No. 2003-86281). 
     Springback occurs in such a terminal connecting body that is obtained by performing the bending process. The springback is a tendency to return to the developed shape. For this reason, for example, in the terminal metal fittings disclosed in Japanese Patent Application Laid-open No. 2004-31034, Japanese Patent Application Laid-open No. 2005-5109, and Japanese Patent Application Laid-open No. 2003-86281, a piece part (a regulated projection unit or a holding piece) is provided on one end side of the terminal connecting body, and a groove (a regulating groove or a holding groove) into which the piece part is fitted is formed on the other end side of the terminal connecting body. In this manner, the terminal connecting body is prevented from deforming outwardly because of the springback. In a coating crimping part of the terminal metal fitting, the thickness of the barrel piece is made thinner than the thickness of the bottom part, or the thickness of the bottom part is made thinner than the thickness of the barrel piece. This is done to reduce the orthogonal sectional shape (shape of a section orthogonal to the axis line direction of an electric wire) after the electric wire is crimped to the coating portion (such as Japanese Utility Model Application Laid-open No. 6-80263 and Japanese Patent Application Laid-open No. 2013-232333). 
     The conventional terminal metal fitting adopts a structure in which the piece part is fitted into the groove, so as to prevent the terminal connecting body from deforming outwardly because of the springback. However, because the terminal metal fitting adopts the fitting structure, a gap between the piece part and the groove is very small. Thus, it is difficult to correctly fit the piece part into the groove, during the bending process of the terminal connecting body. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a terminal metal fitting that can be produced with excellent productivity and in which a terminal connecting body has an outward deformation preventing structure. 
     In order to achieve the above mentioned object, a terminal metal fitting according to one aspect of the present invention includes an electric wire connecting body to which an end of an electric wire is electrically connected; and a terminal connecting body that has an axis line direction set to a connecting direction of the terminal connecting body with a counterpart terminal to be electrically connected to the terminal connecting body, and that is formed into a box shape with a terminal side plate body made of metal being bent at a plurality of portions between one end side and another end side around an axis line, wherein the terminal connecting body includes a first engaging part and a second engaging part on the one end side and the other end side, respectively, that engage each other movements of an end of the one end side and an end of the other end side in separating directions, the movements being due to springback in response to the bending, the terminal connecting body has a first gap, formed between the first engaging part and the end of the other end side, that enables the end of the one end side and the end of the other end side to move each other in directions opposite to the separating directions, and has a second gap, formed between the second engaging part and the end of the one end side, that enables the end of the one end side and the end of the other end side to move each other in directions opposite to the separating directions, the first engaging part is a piece part that is bent at the end of the one end side as a base along a direction of the bending, and projected from the end of the one end side toward the end of the other end side, the second engaging part includes an end surface of a notch that is provided on the other end side as an engagement surface or an engagement point with the first engaging part, and the first gap and the second gap are formed so that the first engaging part is insertable into the notch while being bent at the base. 
     According to another aspect of the present invention, in the terminal metal fitting, it is desirable that the first engaging part and the second engaging part are disposed at one end of the terminal connecting body in the axis line direction, and the second gap is desirably formed also between the end of the one end side and the end of the other end side and is extended toward the other end side in the axis line direction. 
     According to still another aspect of the present invention, in the terminal metal fitting, it is desirable that the first gap and the second gap are formed so that when the second gap becomes small, and the second engaging part abuts the end of the one end side or the end of the one end side abuts the end of the other end side, a size of the first gap remains so that the first engaging part is bendable from the base and the first engaging part is insertable into the notch. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a terminal metal fitting of an embodiment; 
         FIG. 2  is a side view illustrating the terminal metal fitting of the embodiment; 
         FIG. 3  is a top view illustrating a terminal chain body including the terminal metal fitting in its developed shape and the terminal metal fitting in its formed shape; 
         FIG. 4  is a sectional view of a terminal connecting body cut along line X 1 -X 1  in  FIG. 2 ; 
         FIG. 5  is a sectional view of the terminal connecting body cut along line X 2 -X 2  in  FIG. 2 ; 
         FIG. 6  is a sectional view of the terminal connecting body cut along line X 3 -X 3  in  FIG. 2 ; 
         FIG. 7  is a sectional view of a coating crimping part in the developed shape, cut along line Y-Y in  FIG. 3 ; 
         FIG. 8  is a top view illustrating the terminal metal fitting to which an electric wire is crimped; and 
         FIG. 9  is a conceptual sectional view of the coating crimping part and the electric wire cut along line Z-Z in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of a terminal metal fitting according to the present invention will be described in detail with reference to the accompanying drawings. It is to be noted that the present invention is not limited to the embodiment. 
     Embodiment 
     An embodiment of the terminal metal fitting according to the present invention will now be described with reference to  FIG. 1  to  FIG. 9 . 
     Reference numeral  1  from  FIG. 1  to  FIG. 3  denotes a terminal metal fitting of the present embodiment. The terminal metal fitting  1  is electrically connected to an electric wire  100  ( FIG. 9 ), and is electrically connected to a counterpart terminal (not illustrated) while being integrated with the electric wire  100 . In this example, to expose a predetermined length of a core wire  101 , the predetermined length of coating  102  of an end of the electric wire  100  is peeled off and removed. The core wire  101  may be an assembly of a plurality of strands or a single line such as a coaxial cable. To be electrically connected to the electric wire  100 , the terminal metal fitting  1  is crimped to the end of the electric wire  100 . Thus, the terminal metal fitting  1  is electrically connected to the exposed end of the core wire  101 . 
     The terminal metal fitting  1  is obtained by punching a metal plate (such as a copper plate) that is a base material into its predetermined developed shape (the upper portion in  FIG. 3 ), and performing a bending process and the like on the plate, so as to form the metal plate into a predetermined shape capable of being connected to the counterpart terminal and the electric wire  100  (the lower portion in  FIG. 3 ). The terminal metal fitting  1  includes an electric wire connecting body  10  to which an end of the electric wire  100  is electrically connected, and a terminal connecting body  20  that is electrically connected to a counterpart terminal. The electric wire connecting body  10  and the terminal connecting body  20  are coupled by a coupling body  30  interposed therebetween. 
     The terminal metal fitting  1  in its developed shape includes an electric wire side plate body  10 A having a plate shape that is formed into the electric wire connecting body  10 , a terminal side plate body  20 A having a plate shape that is formed into the terminal connecting body  20 , and a coupling body  30 A having a plate shape that is formed into the coupling body  30 . A plurality of terminal metal fittings  1  in their developed shapes that are arranged on the base material are punched out as a chain body (hereinafter, referred to as a “terminal chain body”). The terminal chain body is an assembly of the terminal metal fittings  1  that are arranged in parallel at equal intervals while facing the same direction, and that are joined in a chained state. In the terminal chain body, one end of each of all the terminal metal fittings  1  is joined by a coupling piece  40 . For example, the coupling piece  40  is formed into a rectangular plate shape, and is disposed relative to the electric wire connecting body  10  (electric wire side plate body  10 A) of each of all the terminal metal fittings  1  with a predetermined interval therebetween. For example, a bottom part  12   a , which will be described below, of the electric wire connecting body  10  (electric wire side plate body  10 A) and the coupling piece  40  are joined by a joining part  50  having a rectangular plate shape, for each of the terminal metal fittings  1 . The bending process or the like is performed on each of the terminal metal fittings  1  in their developed shapes, of the terminal chain body. 
     In the terminal metal fitting  1 , the longitudinal direction is defined as a connecting direction (inserting direction) with the counterpart terminal. Thus, it is assumed that the terminal metal fitting  1  has an axis line along the connecting direction. Consequently, a direction that is simply referred to as the axis line direction in the following indicates the direction of the axis line along the connecting direction. In the terminal metal fitting  1 , the electric wire  100  is placed on the terminal metal fitting  1  when the terminal metal fitting  1  is crimped to the electric wire  100 . The vertical direction is defined by setting, as a base, a portion in one side where the electric wire  100  is placed. 
     The electric wire connecting body  10  is a portion obtained by performing the bending process on the electric wire side plate body  10 A, and is formed in a U-shape before the electric wire  100  is connected. The electric wire connecting body  10  includes a core wire crimping part  11  that is crimped to the end of the core wire  101 , a coating crimping part  12  that is crimped to the coating  102  at the end of the electric wire  100 , and a coupling part  13  that couples the core wire crimping part  11  and the coating crimping part  12 . 
     The core wire crimping part  11  includes a bottom part  11   a  onto which the core wire  101  is placed when crimping is performed, and two barrel pieces  11   b  and  11   c  that are extended from both ends (both ends in the direction orthogonal to the axis line direction) of the bottom part  11   a  in the oblique upward direction, respectively. A core wire crimping part  11 A that has a rectangular shape and includes the bottom part  11   a , and the barrel pieces  11   b  and  11   c  are provided in the electric wire side plate body  10 A. A serration area is formed on the entire placing surface of the core wire  101 . The serration area is a core wire holding area to hold the core wire  101  being crimped. The adhesion strength between the core wire crimping part  11  and the core wire  101  is increased, by increasing the contact area between the core wire crimping part  11  and the core wire  101  by the presence of irregularities. In this example, the serration area is formed with a plurality of recess portions  11   d  arranged in a rectangular shape. 
     The coating crimping part  12  includes the bottom part  12   a  onto which the coating  102  is placed when crimping is performed, and two barrel pieces  12   b  and  12   c  that are extended in obliquely upward directions from both ends (both ends in the direction orthogonal to the axis line direction) of the bottom part  12   a , respectively. The bottom part  12   a  is joined to the bottom part  11   a  of the core wire crimping part  11  by the coupling part  13  (coupling part  13 A of the electric wire side plate body  10 A). The barrel pieces  12   b  and  12   c  are arranged out of alignment with each other in the axis line direction so that the barrel pieces  12   b  and  12   c  are not overlapped with each other when the barrel pieces  12   b  and  12   c  are crimped to the coating  102  ( FIG. 8 ). The electric wire side plate body  10 A includes a coating crimping part  12 A that has the bottom part  12   a  and the barrel pieces  12   b  and  12   c.    
     The terminal connecting body  20  is formed into a box shape by bending, around the axis line, a plurality of portions between one end side  20   a  ( FIG. 3 ) and another end side  20   b  ( FIG. 3 ) of the terminal side plate body  20 A made of metal that is in the developed shape. The terminal connecting body  20  (terminal side plate body  20 A) includes a lower wall  21  having a rectangular shape that is coupled to the bottom part  11   a  of the core wire crimping part  11  (core wire crimping part  11 A) by the coupling body  30  (coupling body  30 A). The one end side  20   a  and the other end side  20   b  are one side and the other side (one side and the other side in the direction orthogonal to the axis line direction) relative to the lower wall  21 . 
     The one end side  20   a  of the terminal connecting body  20  (terminal side plate body  20 A) includes a side wall  22  and an upper wall  23 . The side wall  22  is a wall that is adjoined to an end of one side of the lower wall  21 , and is bent at about 90 degrees relative to the lower wall  21 . The upper wall  23  is a wall that is adjoined to an end of the side wall  22  in the opposite side of the lower wall  21  side of the side wall  22 , and is bent at about 90 degrees relative to the side wall  22 . The upper wall  23  faces the lower wall  21  after the bending process. In the one end side  20   a  in the developed shape, a free end side of the upper wall  23  in the orthogonal direction described above is an end  20   a   1 . 
     The terminal connecting body  20  (terminal side plate body  20 A) also has another side wall  24  in the other end side  20   b . The side wall  24  is a wall that is adjoined to an end of the lower wall  21  in the other side of the lower wall  21 , and is bent at about 90 degrees relative to the lower wall  21 . In the other end side  20   b  in the developed shape, a free end side of the side wall  24  in the orthogonal direction described above is an end  20   b   1 . 
     When being bent and processed into the terminal connecting body  20  having a box shape, the terminal side plate body  20 A is formed so that the end  20   a   1  of the one end side  20   a  and the end  20   b   1  of the other end side  20   b  are disposed close to each other. 
     The terminal side plate body  20 A includes a spring part  25  arranged apart from and side by side with the end  20   b   1 . The spring part  25  is a substantially rectangular portion extended in the axis line direction, and is coupled to a part of the end  20   b   1  (coupling body  30 A side). The spring part  25  is bent toward the terminal connecting body  20 , bent toward the same direction at a bend line in the end  20   b   1  side, as well as being bent into an L-shape in the middle thereof in its extended direction, so as to be disposed inside the terminal connecting body  20  having a box shape. The L-shaped portion of the spring part  25  holds the counterpart terminal with the lower wall  21 . 
     A press forming machine (not illustrated) applies a force (pressing force) to the upper wall  23  in a pressing direction toward the lower wall  21 , while the bending process is performed on all corresponding portions of the terminal side plate body  20 A. The pressing force is a force against the springback that occurs in response to the bending to form a box shape. Thus, in the terminal connecting body  20 , when the pressing force is removed, there is a possibility that the terminal connecting body  20  may be deformed outwardly in the direction to return to the developed shape, by the springback. The outward deformation separates the end  20   a   1  of the one end side  20   a  and the end  20   b   1  of the other end side  20   b  from each other and prevents the terminal connecting body  20  from maintaining the predetermined box shape. 
     The terminal connecting body  20  of the present embodiment (terminal side plate body  20 A) is provided with an outward deformation preventing structure for preventing the terminal connecting body  20  from deforming outwardly. In the outward deformation preventing structure, the end  20   a   1  of the one end side  20   a  and the end  20   b   1  of the other end side  20   b  are engaged with each other, and the movements thereof in directions separating from each other, which occur because of the springback, are stopped. More specifically, for the engagement, a first engaging part  26  and a second engaging part  27  are provided in the one end side  20   a  and the other end side  20   b , respectively. The first engaging part  26  and the second engaging part  27  of the present embodiment are disposed on one end (side of an opening  20   c  into which the counterpart terminal is inserted ( FIG. 1 )) of the terminal connecting body  20  (terminal side plate body  20 A) in the axis line direction. 
     The first engaging part  26  is a piece part that is bent with the end  20   a   1  of the one end side  20   a  used as a folding line, along the bending direction toward the box shape, and that is projected from the end  20   a   1  of the one end side  20   a  toward the end  20   b   1  of the other end side  20   b . Thus, the wall surface of the first engaging part  26  is arranged along the springback direction. The first engaging part  26  includes an inclined end surface  26   a  that is directed toward the other end side (coupling body  30  side) in the axis line direction, as the first engaging part  26  separates from the end  20   a   1  in the projecting direction. The inclined end surface  26   a  is an end surface of the first engaging part  26  at the other end side in the axis line direction. Because of the inclination, the inclined end surface  26   a  is facing the outward deformation direction in the springback. In the first engaging part  26 , the inclined end surface  26   a  is used as an engagement surface with the second engaging part  27 , or a part of the inclined end surface  26   a  is used as an engagement point with the second engaging part  27 . The end surface of the first engaging part  26  at the one end side in the axis line direction forms a part of the opening  20   c  of the terminal connecting body  20 . 
     The first engaging part  26  is inserted into a notch  28  that is provided in the other end side  20   b  (in this example, the side wall  24 ). The notch  28  is a portion being notched from one end toward another end in the axis line direction, at one end of the end  20   b   1  side of the side wall  24  in the axis line direction. The notch  28  has a shape equivalent to that of the first engaging part  26 . In the side wall  24 , a portion facing the end  20   a   1  of the one end side  20   a  in the notch  28  is also the end  20   b   1  of the other end side  20   b.    
     The second engaging part  27  is provided on the other end side  20   b  (in this example, the side wall  24 ). The second engaging part  27  has an inclined end surface  27   a  that is directed toward the other end side (coupling body  30  side) in the axis line direction while approaching the lower wall  21  from the end  20   b   1 . The inclined end surface  27   a  faces the inclined end surface  26   a  of the first engaging part  26  when the terminal connecting body  20  is formed into a box shape. In the second engaging part  27 , the inclined end surface  27   a  is used as an engagement surface with the inclined end surface  26   a  of the first engaging part  26 , or a part of the inclined end surface  27   a  is used as an engagement point with the inclined end surface  26   a  of the first engaging part  26 . In this example, the inclined end surface  27   a  is also an end surface of the other end side of the notch  28  in the axis line direction. Thus, the second engaging part  27  uses the end surface of the notch  28  as an engagement surface or an engagement point with the first engaging part  26 . The wall surface of the second engaging part  27  of the present embodiment is a piece part that is arranged along the springback direction, and a part of the second engaging part  27  is projected more in the upper direction (in other words, toward the end  20   a   1  side) than the end  20   b   1 . 
     When the first engaging part  26  and the notch  28  have a fitting structure, to perform the bending process on the terminal side plate body  20 A, the first engaging part  26  needs to be fitted into the notch  28  while being bent. In other words, even if a gap is provided between the first engaging part  26  and the notch  28 , the gap is very small. Thus, when the fitting structure is employed, the processing accuracy for the shapes and the sizes of the first engaging part  26  and the notch  28  needs to be enhanced to fit the first engaging part  26  into the notch  28  without fail. However, even if the first engaging part  26  and the notch  28  are formed at great cost in this manner, if a deviation occurs at the bent portion in each part, even if the deviation falls within a tolerance range, there is a possibility that accumulation of the deviations may prevent the first engaging part  26  from being fit into the notch  28 . 
     In the terminal connecting body  20  of the present embodiment, a first gap G 1  ( FIG. 1 ,  FIG. 2 ,  FIG. 4 , and  FIG. 5 ) is formed between the first engaging part  26  and the end  20   b   1  of the other end side  20   b , and a second gap G 2  ( FIG. 1 ,  FIG. 2 ,  FIG. 5 , and  FIG. 6 ) is formed between the second engaging part  27  and the end  20   a   1  of the one end side  20   a . The first gap G 1  and the second gap G 2  each has a size that can move the end  20   a   1  of the one end side  20   a  and the end  20   b   1  of the other end side  20   b  in directions opposite from the respective separating directions due to the springback. In other words, the sizes of the first gap G 1  and the second gap G 2  allow the end  20   a   1  of the one end side  20   a  and the end  20   b   1  of the other end side  20   b  to move (in other words, the end  20   a   1  and the end  20   b   1  to be brought close to each other) in the directions opposite from the separating directions due to the springback. This is made possible by bringing the first engaging part  26  and the end  20   b   1  of the other end side  20   b  into a releasing direction of the engagement between the first engaging part  26  and the second engaging part  27  and bringing the second engaging part  27  and the end  20   a   1  of the one end side  20   a  into a releasing direction of the engagement between the first engaging part  26  and the second engaging part  27  when force is applied in a direction that causes the lower wall  21  and the upper wall  23  to approach each other. 
     In this example, the first gap G 1  and the second gap G 2  are formed into sizes that are set so that the first engaging part  26  can be inserted into the notch  28  while being bent with its base used as a folding line, during each bending process. For example, to obtain the first gap G 1  such as the above, the size of the notch  28  is made larger than that of the first engaging part  26  even if the notch  28  has the same shape as that of the first engaging part  26 . To obtain the second gap G 2  such as the above, the projection amount of the second engaging part  27  described above toward the end  20   a   1  side is made smaller. In this example, the second engaging part  27  is projected more toward the end  20   a   1  side than the end  20   b   1 . Thus, the second gap G 2  is also formed between the end  20   a   1  and the end  20   b   1 . Consequently, the first gap G 1  and the second gap G 2  allow the end  20   a   1  and the end  20   b   1  to be easily brought close to each other. If the second engaging part  27  is not projected more toward the end  20   a   1  side than the end  20   b   1 , it is preferable to form the second gap G 2  between the end  20   a   1  and the end  20   b   1 , and extend the second gap G 2  toward the other end side in the axis line direction, so that it is possible to easily bring the end  20   a   1  and the end  20   b   1  close to each other. 
     For example, during the bending process, the pressing force described above is applied to the upper wall  23  by the press forming machine. Consequently, it is possible to bring the end  20   a   1  and the end  20   b   1  close to each other, with the first gap G 1  and the second gap G 2 , by pressing the upper wall  23  inward toward the lower wall  21  using the pressing force. Thus, for example, the first gap G 1  and the second gap G 2  are formed so that when the second gap G 2  becomes small, and the second engaging part  27  abuts the end  20   a   1  of the one end side  20   a  or the end  20   a   1  of the one end side  20   a  abuts the end  20   b   1  of the other end side  20   b , the first gap G 1  that is interposed between the first engaging part  26  and the end  20   b   1  of the other end side  20   b  remains. The interposed first gap G 1  has a size such that the first engaging part  26  can be bent from its base, and the first engaging part  26  can be inserted into the notch  28 . Consequently, by keep bending the first engaging part  26  from its base in that state by the press forming machine, it is possible to easily insert the first engaging part  26  into the notch  28 . 
     The press forming machine finishes the forming process on the terminal connecting body  20  by weakening the pressing force and finally reducing the pressing force to zero. During this time, in the terminal connecting body  20 , the end  20   a   1  of the one end side  20   a  separates from the end  20   b   1  of the other end side  20   b  when the lower wall  21  separates from the upper wall  23  because of the springback. Consequently, the inclined end surface  26   a  of the first engaging part  26  and the inclined end surface  27   a  of the second engaging part  27  abut each other and are engaged with each other. In this manner, it is possible to prevent the terminal connecting body  20  from deforming outwardly because of the springback. 
     As illustrated above, in the terminal metal fitting  1  of the present embodiment, it is possible to easily insert the first engaging part  26  into the notch  28  and engage the first engaging part  26  with the second engaging part  27  without enhancing the processing accuracy of the first engaging part  26  and the notch  28 . Consequently, the terminal metal fitting  1  can prevent the terminal connecting body  20  from deforming outwardly because of the springback, while maintaining its capability of being produced with good productivity. 
     In the coating crimping part  12 A in the developed shape of the terminal metal fitting  1  of the present embodiment, it is preferable to reduce the thicknesses of the two barrel pieces  12   b  and  12   c  relative to that of the bottom part  12   a  ( FIG. 7 ). In the coating crimping part  12 A, one surface side, on which the coating  102  is placed, that becomes the inside has the same plane, and the thicknesses of the barrel pieces  12   b  and  12   c  are reduced in the outer sides thereof. In this manner, for example, in the coating crimping part  12  that is crimped to the coating  102 , it is possible to reduce the width W ( FIG. 8  and  FIG. 9 ) in the orthogonal direction described above, and reduce the height H ( FIG. 9 ) in the vertical direction, by the barrel pieces  12   b  and  12   c  having thin thicknesses. Consequently, it is possible to reduce the body size. 
     The terminal metal fitting according to the present embodiment can easily insert the first engaging part into the notch and engage the first engaging part with the second engaging part, without enhancing the processing accuracy for the first engaging part and the notch. Thus, the terminal metal fitting can prevent the terminal connecting body from deforming outwardly because of the springback, while maintaining its capability of being produced with good productivity. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.