Patent Publication Number: US-8992271-B2

Title: Electrical terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the filing date under 35 U.S.C. §119(a)-(d) of Japanese Patent Application No. 2012-169949 of Jul. 31, 2012. 
     FIELD OF THE INVENTION 
     The present invention relates to an electrical terminal and, in particular, to an electrical connector for connection with a thin wire. 
     BACKGROUND 
     A known electrical terminal  101  for connection with a wire is disclosed in U.S. Pat. No. 4,003,623 B and shown in  FIGS. 11 and 12 . 
     The known electrical terminal  101  shown in  FIG. 11  includes a pair of side walls  104 ,  105  that extend from opposite sides of a base  103  and face each other. The shown embodiment is substantially U-shaped and includes a cavity  102  therein. The electrical terminal  101  is made by stamping and forming a metal sheet. The base  103  has an elongated shape for receiving wires W 1  and W 2  (see  FIG. 12 ). A plurality of serrations  106  are successively positioned from the upper end of the one side wall  104  to the upper end of the other side wall  105  and disposed along the inner surfaces of the pair of side walls  104 ,  105  and the base  103 . Hence, the serrations  106  formed on the side wall  104  and the serrations  106  formed on the side wall  105  are opposed each other and extend in the same direction. Each of the serrations  106  extends in a direction perpendicular to a length of the base and a direction in which the wires W 1  and W 2  (see  FIG. 12 ) extend when positioned in the cavity  102 . 
     After the two wires W 1  and W 2  are inserted into the cavity  102 , the pair of side walls  104  and  105  are deformed, as shown in  FIG. 12 , to crimp the electrical terminal  101  onto the wires W 1  and W 2 . Then, the side wall  104  wraps around the periphery of the wire W 1 , while the side wall  105  wraps around the wire W 2 . In this situation, each serration  106  bites into the wires W 1  and W 2 . 
     Another known electrical connector  201  for connection with a thin wire like a coil winding is disclosed in Japanese Patent No. JP S52-114987 A, as shown in  FIG. 13   
     As shown, the known electrical connector  201  includes a housing  210  having a terminal receiving section  211  and an electrical terminal  220  for insertion into the terminal receiving section  211 . 
     First grooves  212  are disposed along both upper sides of the terminal receiving section  211  of the housing  210 . Second grooves  213  are disposed along both lower sides of the terminal receiving section  211  of the housing  210 . In addition, a wire wound section  215  is provided at a back side of an upper wall  214  of the housing  210 , in order to wind a wire  216  around the wire wound section  215 . The wire  216  is a thin electrical insulated wire of, for example, approximately A.W.G #50 having a metal core and an insulator covering the outer part of the metal core. 
     On the other hand, the electrical terminal  220  is made by stamping and forming a metal sheet, and includes a base  221  having a substantially rectangular flat plate shape. A plurality of lances  221   a  and  221   b  are positioned along opposites sides of the base  221 . Moreover, the electrical terminal  220  is provided with a front side plate  222  extending obliquely forward from the front end of the base  221  and a back side plate  224  extending from the back end of the base  221  to be folded back obliquely. A side plate  223  extends in such a manner as to be folded back backward from a tip  222   a  of the front side plate  222 . A plurality of serrations  225  are disposed on the surface of the side plate  223 . The end of back side plate  224  is positioned between a pair of flanges  223   a  positioned at both sides of the side plate  223  and folded downward there from. Lances  223   b  are provided at ends of the pair of flanges  223   a , respectively. 
     Then, the electrical terminal  220  is inserted into the terminal receiving section  211  of the housing  210 . Accordingly, the base  221 , the front side plate  222 , the side plate  223 , and the back side plate  224  are inserted into the terminal receiving section  211 . Additionally, the lances  223   b  are pressed into the first grooves  212 , respectively, and the lances  221   a  and  221   b  are pressed into the second grooves  213 , respectively. Moreover, when the tip  222   a  of the front side plate  222  abuts against an end wall, not shown, of the housing  210 , the base  221  is moved in the direction of an arrow, and then the front side plate  222  is turned around a fixed end thereof. Accordingly, each of the serrations  225  formed on the side plate  223  engages the wire  216 . 
     Furthermore, another example of a known electrical connector for connection with a thin wire like a coil winding is disclosed in Japanese Patent No. JP H10-302857 A, as shown in  FIG. 14 . 
     The known electrical connector  301  shown in  FIG. 14  includes a housing  310 , a first terminal  320  press-fitted into a first cavity  311  of the housing  310 , and a second terminal  330  press-fitted into a second cavity  312  of the housing  310 . 
     The first terminal  320  is made by stamping and forming a metal sheet, and includes a base  324  press-fitted into the first cavity  311 , and a contact part  321  having a gently arcuate shape curved toward a wire receiving surface  313  of the housing  310 . A plurality of serrations  322  are disposed on a surface of the contact part  321  and positioned opposite to the wire receiving surface  313 . A vertex  323  is formed at the end of the first terminal  320  at the contact part  321  side. 
     Furthermore, the second terminal  330  is made by stamping and forming a metal sheet, and has a pressing part  331  disposed at the tip thereof to press the vertex  323  of the first terminal  320  toward the wire receiving surface  313 . 
     Then, a wire  330  is disposed between the wire receiving surface  313  and the contact part  321 . When the second terminal  330  is press-fitted, the pressing part  331  of the second terminal  330  presses the vertex  323  of the first terminal  320  toward the wire receiving surface  313 . This permits the contact part  321  of the first terminal  320  to elastically contact with the wire  330 . When the contact part  321  elastically contacts the wire  330 , the serrations  322  formed on the contact part  321  engage the wire  330 . The wire  330  is a thin insulated electrical wire of, for example, approximately A.W.G #50 having a metal core and an insulator covering the outer part of the metal core 
     Each of the known electrical terminals  101 ,  201  and  301  have the following disadvantages. 
     As for the known electrical terminal  101  shown in  FIG. 11  and  FIG. 12 , the cavity  102  that receives the wires W 1  and W 2  is large, notably when a thin wire like a coil winding is connected. The pair of side walls  104  and  105  are not completely rounded and some portions remain. This makes it difficult to connect such a thin wire in a stable manner, especially when a single thin wire is connected. Herein, the thin wire denotes a wire having a diameter of for example, approximately 0.02 mm to 0.25 mm. 
     As for the known electrical connector  201  shown in  FIG. 13 , it is difficult to narrow the pitch of the base  221 , the side plate  223 , and the like of the electrical terminal  220  that have a wide width. Furthermore, the housing  210  is necessary in addition to the electrical terminal  220  to connect the wire  216 , thereby posing a problem that the number of component parts is large. 
     As for the electrical connector  301  shown in  FIG. 14 , the wire  301  for connection is the thin insulated electrical wire of, for example, approximately A.W.G #50 including the metal core and the insulator covering the outer part of the metal core. Therefore, stable connection can be achieved when the thin wire like the coil winding is connected. However, the housing  310  is necessary in addition to the first and second terminals  320  and  330  to connect the wire  301 , thereby posing a problem that the number of component parts is large. 
     SUMMARY 
     Accordingly, the present invention has been made in view of the aforementioned disadvantages and shortcoming, and it is an object of the present invention, among others to provide having a first member and a second member. The first member includes a pair of connecting face portions, a coupling portion, and a plurality of serrations. The pair of connecting face portions face each other in a substantially V shape such that a gap between inner faces of the pair of connecting face portions gradually becomes smaller from a wider-gap side to a narrower-gap side. The coupling portion connects the pair of connecting face portions at ends of the narrower-gap side of the inner faces. The plurality of serrations are disposed on the pair of inner faces and extend along intersecting directions. The second member has a substantially U shape that mates with the pair of connecting face portions and can displace outer side faces of the pair of connecting face portions inward to urge the inner faces closer to each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, features and advantages of the invention will become more apparent by describing in detail embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an electrical terminal according to the invention; 
         FIG. 2  is a perspective view of the electrical terminal shown in  FIG. 1 , showing a second member mated with a first member after a wire is inserted into the first member; 
         FIG. 3  is a front view the electrical terminal according to the present invention and a state before the second member is mated with the first member; 
         FIG. 4  is a front view of the electrical terminal according to the invention when the second member is mated with the first member after the wire is inserted into the first member; 
         FIG. 5  is a right side view the electrical terminal according to the invention and before the second member is mated with the first member; 
         FIG. 6  is a right side view of the electrical terminal according to the invention and after the second member is mated with the first member after the wire is inserted into the first member; 
         FIG. 7A  is a schematic diagram showing a wire being connected with the pair of connecting face portions; 
         FIG. 7B  is a schematic diagram showing the wire in  FIG. 7A  being connected with the pair of connecting face portions; 
         FIG. 7C  is a schematic diagram showing the wire of  FIG. 7B  being connected with the pair of connecting face portions and a plurality of serrations intersecting with each other; 
         FIG. 8A  is a partial front view of the wire of  FIG. 7A  that was connected with the pair of connecting face portions; 
         FIG. 8B  is a partial plan view of the wire of  FIG. 7A  that was connected with the pair of connecting face portions; 
         FIG. 8C  is a cross-sectional view taken along a line  8 C- 8 C in  FIG. 8A ; 
         FIG. 9  is a perspective view another electrical terminal according to the invention and before a second member is mated with a first member; 
         FIG. 10  is a perspective view the electrical terminal shown in  FIG. 9  after the second member is mated with the first member; 
         FIG. 11  is a perspective view of a known electrical terminal; 
         FIG. 12  is an schematic diagram showing two wires that are connected with the known electrical terminal shown in  FIG. 11 ; 
         FIG. 13  is a perspective view of another known electrical connector; and 
         FIG. 14  is a cross-sectional view of another known electrical connector. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
     With reference to  FIGS. 1 through 6 , an electrical terminal  1  according to the invention will be described. A thin wire  40 , such as a coil winding, is connected to the electrical terminal  1 . The thin wire  40  is, for example, an electrical insulated wire having a metal core and an insulator covering the outer part of the metal core and having a diameter of approximately 0.02 mm to 0.25 mm, or a metal core having a diameter of approximately 0.02 mm to 0.25 mm. An example of the electrical insulated wire is a magnet wire. Hereinafter, an example of the magnet wire used as the wire  40  will be described. 
     The electrical terminal  1  shown in  FIG. 1  to  FIG. 6  is made by stamping and forming a metal sheet and includes a first member  10 , a second member  20 , and a coupling member  30  for coupling the first member  10  with the second member  20 . 
     The first member  10  includes a pair of connecting face portions  11  and a coupling portion  12  that connects the pair of connecting face portions  11 . 
     The pair of connecting face portions  11  face with each other, and are formed in a substantially V shape, in the embodiment shown, such that a gap between inner faces  11   a  facing with each other is gradually smaller from a wider-gap side to a narrower-gap side. Each connecting face portion  11  is plate shapes. Upper ends of the pair of connecting face portions  11  have a wider gap between the inner faces  11   a  that the lower ends of the pair of connecting face portions  11 , which have a narrower gap there between. As shown in  FIG. 3 , as to the gaps between the inner faces  11   a  of the pair of connecting face portions  11  facing with each other, a width d 1  represents a wider-gap side and a width d 2  represents a narrower-gap side. The width d 1  is set to be larger than the diameter of the wire  40 , whereas the width d 2  is set to be smaller than the diameter of the wire  40 . Additionally, the pair of connecting face portions  11  are formed in such a manner that the inner faces  11   a  facing with each other are curved outward from the narrower-gap side to the wider-gap side. 
     The pair of connecting face portions  11  receives the wire  40  from the wider-gap side of the inner faces  11   a  facing with each other, and hold the wire with the inner faces  11   a  facing with each other. A plurality of serrations  11   b  and  11   c  are provided. In the shown embodiment, the plurality of serrations  11   b  and  11   c  extend in a direction in which the axial line of the received wire  40  extends, i.e., in a direction intersecting with the front-back direction on the inner faces  11   a  of the pair of connecting face portions  11  facing with each other. As shown in  FIG. 7A ,  FIG. 7B , and  FIG. 7C , the plurality of serrations  11   b  and  11   c  are disposed along the inner faces  11   a  of the pair of connecting face portions  11  facing with each other extend in directions intersecting with each other. 
     The coupling portion  12  connects the pair of connecting face portions  11  at the ends of the narrower-gap side, which is the lower ends, of the inner faces  11   a  facing with each other. As illustrated in  FIG. 3 , the coupling portion  12  includes a first curved portion  12   a  curved outward from the lower end of one of the pair of connecting face portions  11 , a second curved portion  12   b  curved outward from the lower end of the other of the connecting face portion  11 , and a connecting portion  12   c  for connecting the end of the first curved portion  12   a  with the end of the second curved portion  12   b.    
     Moreover, the second member  20  is substantially U shaped in the shown embodiment. The second member  20  includes a flat plate portion  21  having a substantially rectangular shape that extends in the front-back direction, and a pair of side plates  22  extending downward from both ends of the flat plate portion  21  in the width direction. As shown in  FIG. 4  and  FIG. 6 , the second member  20  is mated with the pair of connecting face portions  11  from the wider-gap side of the inner faces  11   a  of the pair of connecting face portions  11  facing with each other. The pair of side plates  22  of the second member  20  displaces inward both outer side faces  11   e  of the pair of connecting face portions  11  to urge the inner faces  11   a  of the pair of connecting face portions  11  facing with each other closer together. Accordingly, the plurality of serrations  11   b  and  11   e  engage the wire  40 , and the wire  40  is connected with the pair of connecting face portions  11 . 
     Tapered portions  11   d  and  22   a  for guiding each other are respectively arranged on the outer faces of the ends of the pair of connecting face portions  11  on the wider-gap side of the inner faces  11   a  facing with each other, and on the inner faces of the ends of the pair of side plates  22  of the second member  20 . 
     In the shown embodiment, the coupling member  30  is substantially rectangular flat plate, and is connected to the connecting portion  12   c  of the coupling portion  12  through a first coupling piece  31  coupled with the lower end of the flat plate, and is also coupled with the flat plate portion  21  of the second member  20  through a second coupling piece  32  coupled with the upper end of the flat plate. 
     A method of connecting the wire  40  with the electrical terminal  1  configured as described above will be described with reference to  FIGS. 1 to 7 . 
     Firstly, as shown in  FIG. 1 ,  FIG. 3  and  FIG. 5 , the second member  20  is spaced apart from the first member  10 , and the wire  40  is inserted from the wider-gap side of the inner faces  11   a  of the pair of connecting face portions  11  facing each other. Accordingly, the wire  40  is secured between the inner faces  11   a  of the pair of connecting face portions  11 . As to the gap between the inner faces  11   a , d 1  represents the gap of the wider-gap side and d 2  represents the gap of the narrower-gap side. Moreover, since the width d 1  of the wider-gap side is larger than the diameter of the wire  40 , it is possible to insert the wire  40  with ease from the wider-gap side of the inner faces  11   a  of the pair of connecting face portions  11  facing with each other. Furthermore, since the width d 2  of the narrower-gap side is set to be smaller than the diameter of the wire  40 , it is possible to hold the wire  40  with certainty between the inner faces  11   a  of the pair of connecting face portions  11  facing with each other. 
     Next, as illustrated in  FIG. 2 ,  FIG. 4  and  FIG. 6 , the second member  20  is mated with the pair of connecting face portions  11  from the wider-gap side of the inner faces  11   a . Then, the inner side faces of the pair of side plates  22  displace both outer side faces  11   e  of the pair of connecting face portions  11  inward. In more detail, while the inner side faces of the pair of side plates  22  move downward, the inner side faces push the upper-end outer side faces  11   e  of the pair of connecting face portions  11  inward. Accordingly, both outer side faces  11   e  displace in such a manner as to rotate inward around the lower ends (the ends on the narrower-gap side) of the pair of connecting face portions  11 . As a result, the inner faces  11   a  of the pair of connecting face portions  11  rotate inward around the lower ends of the pair of connecting face portions  11 , and are urged closer to each other. This causes the plurality of serrations  11   b  and  11   c  formed on the inner faces  11   a  bite into the wire  40 , and thus the wire  40  is connected with the pair of connecting face portions  11 . When the plurality of serrations  11   b  and  11   c  bite into the wire  40 , the insulator covering the outer part of the wire  40  is deformed and then the plurality of serrations  11   b  and  11   c  are electrically connected with the metal core of the wire  40 . 
     In this manner, by mating the second member  20  with the pair of connecting face portions  11  of the first member  10 , the inner faces  11   a  are made to move closer to each other. Accordingly, the plurality of serrations  11   b  and  11   c  bite into the wire  40  to connect the wire  40  with the pair of connecting face portions  11 . Hence, even if the thin wire  40  like a coil winding is connected, it is possible to connect the wire  40  in a stable manner without any remaining portion of the pair of connecting face portions  11 . In particular, this advantage is remarkable when the single thin wire  40  is used for connection. It is noted that when the wire  40  of the same diameter is used for connection, the two wires  40  may be connected. 
     Moreover, the second member  20  displaces both outer side faces  11   e  inward to make the inner faces  11   a  closer to each other and connect the wire  40  with the pair of connecting face portions  11 . Accordingly, when a plurality of electrical terminals  1  are arranged in a direction in which the pair of connecting face portions  11  face with each other, it is possible to achieve the narrower pitch. 
     Furthermore, since the wire  40  can be connected only by the first member  10  and the second member  20  constituting the electrical terminal  1 , the wire  40  can be connected using the electrical terminal  1 . 
     In the shown embodiment, the pair of connecting face portions  11  are formed in such a manner that the inner faces  11   a  are curved outward from the narrower-gap side of the inner faces  11   a  facing with each other to the wider-gap side. Hence, when the inner faces  11   a  of the pair of connecting face portions  11  rotate inward around the lower ends (the ends on the narrower-gap side) of the pair of connecting face portions  11  and come closer to each other, the ends of the inner faces  11   a  on the wider-gap side do not come in contact with each other before the wire  40  is connected. Accordingly, by managing the gap between the ends of the inner faces  11   a  facing with each other on the wider-gap side, it is made possible to determine whether or not the wire  40  is connected. 
     The tapered portions  11   d  and  22   a  for guiding each other are arranged on the outer faces of the ends of the pair of connecting face portions  11  respectively, on the wider-gap side of the inner faces  11   a , and on the inner faces of the ends of the second member  20 . Accordingly, when the second member  20  is mated with the pair of connecting face portions  11  from the wider-gap side of the inner faces  11   a , mating is accomplished. 
     Additionally, the plurality of serrations  11   b  and  11   c , respectively formed on the inner faces  11   a , extend in directions intersectional to each other, as shown in  FIG. 7A ,  FIG. 7B  and  FIG. 7C . Accordingly, when the plurality of serrations  11   b  and  11   c  are electrically connected with the metal core of the wire  40 , dents  41  are formed on the wire  40  by the plurality of serrations  11   b , as shown, the dents  42  intersect to each other, as shown in  FIG. 8A ,  FIG. 8B , and  FIG. 8C . When the dents  41  and  42  are arranged to intersect each other, the areas of thinned portions are smaller than that of the case where the dents  41  and  42  are opposed to each other and extend in the same direction. In the shown embodiment, the dents  41  and  42  are arranged to intersect each other, which makes the areas of thinned portions small. Therefore, even if the wire  40  is thin like a coil winding, the wire is hardly disconnected. 
     In addition, according to the electrical terminal  1 , the coupling portion  12  of the first member  10  and the second member  20  are coupled by the coupling member  30 . This means that the first member  10  and the second member  20  are not separated. Therefore, as there is no possibility that one of the first member  10  and the second member  20  is lost, it is possible to manage the components with ease. Moreover, as the electrical terminal  1  is integrally formed, it is unnecessary to separately manufacture the first member  10  and the second member  20 , and it is possible to produce the electrical terminal  1  at low cost. 
     Furthermore, the coupling portion  12  includes the first curved portion  12   a  curved outward from the lower end of the one connecting face portion  11 , the second curved portion  12   b  curved outward from the lower end of another connecting face portion  11 , and the connecting portion  12   c  for connecting the end of the first curved portion  12   a  with the end of the second curved portion  12   b . Hence, it becomes possible to connect the connecting portion  12   c  to a metal carrier strip (not shown) through a coupling piece (not shown). In addition, as the coupling portion  12  includes the first curved portion  12   a  and the second curved portion  12   b , it is possible to relieve stress along the lower ends of the pair of connecting face portions  11 , when the inner faces  11   a  rotate inward around the lower ends of the pair of connecting face portions  11  and come closer to each other. 
     Next, an electrical terminal according to another embodiment of the invention will be described with reference to  FIG. 9  and  FIG. 10 . 
     The electrical terminal  1  shown in  FIG. 9  and  FIG. 10  has the same basic structure as that of the electrical terminal  1  shown in  FIG. 1  to  FIG. 6 . In  FIG. 9  and  FIG. 10 , the plurality of serrations are not illustrated. However, the electrical terminal  1  shown in  FIG. 9  and  FIG. 10  differs from the electrical terminal  1  shown in  FIG. 1  to  FIG. 6  in that a lock  50 , to be locked when the second member  20  is mated with the pair of connecting face portions  11 , is provided on the pair of connecting face portions  11  and the second member  20 . 
     Herein, the lock  50  includes a pair of locking protrusions  51  formed in a protruding manner at upper-end edges of the pair of connecting face portions  11 , respectively, and a locking opening  52  formed in the flat plate portion  21  of the second member  20 . When the second member  20  is mated with the pair of connecting face portions  11 , the pair of locking protrusions  51  are inserted into the locking opening  52 . A tapered portion  51   a  is disposed on the upper-end outer side face of each of the locking protrusions  51 . This assists insertion of the pair of locking protrusions  51  into the locking opening  52  with ease. Then, when the pair of locking protrusions  51  are inserted into the locking opening  52 , the locking protrusions  51  abut against the edges of the locking opening  52  in the width direction. This prevents the pair of connecting face portions  11  from opening. Therefore, the pair of connecting face portions  11  are prevented from opening when the second member  20  is mated with the pair of connecting face portions  11 . It is thus possible to avoid the wire  40  from being discontinuous. 
     Moreover, the electrical terminal  1  shown in  FIG. 9  and  FIG. 10  also differs from the electrical terminal  1  shown in  FIG. 1  to  FIG. 6  in that a mating portion  60  to be mated with a mating connector (not shown) is disposed at the coupling portion  12  of the first member  10 . 
     More specifically, in the electrical terminal  1  shown in  FIG. 9  and  FIG. 10 , the mating portion  60  is tab shaped and connects at the connecting portion  12   c  through a coupling piece  61 . The mating portion  60  is folded downward through the coupling piece  61 , and is configured to be mated with an electrical terminal (not illustrated) of the mating connector. 
     Although the exemplary embodiment of the invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 
     For example, the inner faces  11   a  facing each other are not necessarily formed to be curved outward from the narrower-gap side of the inner faces  11   a  facing with each other to the wider-gap side. 
     Moreover, in the electrical terminal  1 , the coupling portion  12  of the first member  10  and the second member  20  may be not connected using the coupling member  30 . 
     Moreover, in the electrical terminal  1 , it may not necessary that the tapered portions  11   d  and  22   a  that guide respective counterparty members are provided on the outer faces of the ends of the pair of connecting face portions  11  on the wider-gap side of the inner faces  11   a  and on the inner faces of the ends of the second member  20 . 
     In the electrical terminal  1 , it may not be necessary that the plurality of serrations  11   b  and  11   c  formed on the respective faces  11   a  extend in directions intersecting with each other. 
     Furthermore, it may not be necessary that the coupling portion  12  includes the first curved portion  12   a , the second curved portion  12   b , and the connecting portion  12   c  as long as the coupling portion  12  couples the pair of connecting face portions  11  together.