Patent Publication Number: US-9847596-B2

Title: Terminal fitting and method of manufacturing wire with terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application PCT/JP2014/056880, filed on Mar. 14, 2014, and designating the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a terminal fitting included in a wire harness disposed in an automobile, and a method of manufacturing a wire with a terminal having the terminal fitting. 
     2. Description of the Related Art 
     Generally, a wire harness for transmitting electric power or a control signal is disposed between electronic devices. A wire harness includes one or more wires, a terminal fitting crimped to a terminal of each wire, and a connector storing the terminal fitting. This connector is fitted to a counterpart connector, whereby an electrical connection is established. A connector used for a wire harness of this type generally includes a tubular connector housing, herein a terminal fitting is stored in a terminal storage chamber (cavity) formed on the connector housing. 
     A terminal fitting is formed by, for example, bending a conductive plate, and includes a wire connection part connected to a wire, and an electric contact part connected to a terminal fitting in a counterpart connector. The wire connection part has a crimp part (barrel piece) crimped to a terminal of a wire with caulking, and a saw-like serration part is formed on an inner surface of the crimp part for holding a core of a wire to ensure electrical connection. There is also proposed a terminal structure in which a water stop member is provided on an inner surface of a crimp part of a wire connection part in order to close a gap with a wire to prevent water from entering a core and a serration part (see, for example, WO 2011/122622 A1). 
     As illustrated in  FIGS. 15, 16A, 16B, 16C, 16D, and 16E , a crimp terminal  100  described in Patent Literature 1 is a female terminal connected to a counterpart male terminal, and includes an electric contact part  101  in a rectangular cylindrical shape, a wire connection part  102  mounted at the back of the electric contact part  101  and connected to a wire W, and a coupling part  103  with a cross-section of a reversed C shape, the coupling part  103  coupling these parts. As illustrated in  FIGS. 16A, 16B , and  16 C, the wire connection part  102  has a barrel piece  104  with a cross-section of an almost U shape which is open to one side before it is caulked (before crimped), and a saw-like serration part  105  for holding a core W 1  of the wire W is formed on an inner surface of the barrel piece  104 . The barrel piece  104  also has a sheet-type holding part  106  extending backward from the serration part  105 . This holding part  106  holds an insulating coating W 2  of the wire W. 
     The barrel piece  104  of the crimp terminal  100  is also provided with a water stop member  107  formed continuously along edges of four sides on its inner surface, and a water stop member  108  formed along an edge of an opening on one outer surface. As illustrated in  FIGS. 16D and 16E , in the state in which the barrel piece  104  is caulked to be crimped to the wire W, the opening edges of the barrel piece  104  are overlapped to cover the wire W, the inner water stop member  107  is in close contact with the insulating coating W 2  of the wire W, and the water stop members  107  and  108  are in close contact with each other at the overlapping part. In addition, the barrel piece  104  is crushed with the coupling part  103  by caulking at the front part of the wire connection part  102 , whereby the inner water stop member  107  closes the gap between edges of the barrel piece  104 . Thus, the connection part between the core W 1  of the wire W and the serration part  105  is waterproofed. 
     However, in the conventional terminal fitting described in WO 2011/122622 A1, the barrel piece  104  is crushed with the coupling part  103  by caulking at the front part of the wire connection part  102 , so that the core W 1  of the wire W is surrounded by the barrel piece  104 . Therefore, as the position of the tip end of the core W 1  cannot be confirmed, positioning precision for the wire W in a crimping process is required. This might cause various troubles. For example, labor and time for the crimping process increases, causing deteriorated efficiency; a connection failure occurs between the core W 1 , that is shifted backward, and the serration part  105 ; or the caulking resistance increases due to the core W 1  shifted forward. 
     SUMMARY OF THE INVENTION 
     The present invention is accomplished in view of the above circumstances, and aims to provide a terminal fitting and a method of manufacturing a wire with a terminal, which can enhance working efficiency in a crimping process as well as prevent failure in connection with a wire. 
     In order to solve the above-mentioned problems, a terminal fitting according to one aspect of the present invention includes an electric contact part connected to a counterpart terminal from front; and a wire connection part connected to a wire at a back of the electric contact part. Herein, the wire connection part includes a barrel piece which is caulked while covering a tip end of the wire, thereby being crimped to the wire; a serration part formed on an inner surface of the barrel piece and connected to a core of the wire; and a water stop part mounted on the inner surface of the barrel piece to close a gap with the wire. A positioning unit mounted anterior to the serration part to position a tip end of the core is mounted to at least one of the barrel piece and the water stop part. 
     Further, in the terminal fitting according to another aspect of the present invention, the positioning unit is formed such that a projecting piece projecting forward at a circumferential end of the barrel piece or the water stop part is deformed toward the core by caulking, or the positioning unit is formed such that a front end of the barrel piece is deformed toward the core by caulking. 
     In order to solve the above-mentioned problems, a manufacturing method according to still another aspect of the present invention for manufacturing a wire with a terminal is the manufacturing method for manufacturing the wire with the terminal by crimping the above-mentioned terminal fitting the wire. The method includes applying a liquid water stop material onto an inner surface of the barrel piece to form the water stop part, or attaching a sheet-type water stop material to the inner surface of the barrel piece to form the water stop part; and deforming the barrel piece into a cylinder by caulking to cover the tip end of the wire as well as to cause the water stop part to be in close contact with the wire. 
     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 wire with a terminal according to a first embodiment of the present invention; 
         FIG. 2  is a perspective view illustrating a terminal fitting used for the wire with a terminal according to the first embodiment of the present invention; 
         FIG. 3A  is a sectional view illustrating the wire with a terminal according to the first embodiment of the present invention; 
         FIG. 3B  is a sectional view along a line B-B in  FIG. 3A ; 
         FIG. 4  is a sectional view illustrating a modification of the wire with a terminal according to the first embodiment of the present invention; 
         FIG. 5  is a perspective view illustrating a manufacturing procedure of the wire with a terminal according to the first embodiment of the present invention; 
         FIG. 6  is a perspective view illustrating a wire with a terminal according to a second embodiment of the present invention; 
         FIG. 7  is a perspective view illustrating a terminal fitting used for the wire with a terminal according to the second embodiment of the present invention; 
         FIG. 8  is a sectional view illustrating the wire with a terminal according to the second embodiment of the present invention; 
         FIG. 9  is a perspective view illustrating a manufacturing procedure of the wire with a terminal according to the second embodiment of the present invention; 
         FIG. 10A  is a perspective view illustrating a part of the wire with a terminal according to the second embodiment of the present invention; 
         FIG. 10B  is a perspective view illustrating a part of the wire with a terminal according to the second embodiment of the present invention; 
         FIG. 11  is a perspective view illustrating a wire with a terminal according to a third embodiment of the present invention; 
         FIG. 12  is a perspective view illustrating a terminal fitting used for the wire with a terminal according to the third embodiment of the present invention; 
         FIG. 13A  is a sectional view illustrating the wire with a terminal according to the third embodiment of the present invention; 
         FIG. 13B  is a sectional view along a line B-B in  FIG. 13A ; 
         FIG. 13C  is a sectional view along a line C-C in  FIG. 13A ; 
         FIG. 13D  is a sectional view along a line D-D in  FIG. 13A ; 
         FIG. 14A  is a sectional view illustrating a modification of the wire with a terminal according to the third embodiment of the present invention; 
         FIG. 14B  is a sectional view along a line B-B in  FIG. 14A ; 
         FIG. 15  is an exploded perspective view illustrating a conventional wire with a terminal; 
         FIG. 16A  is a side view illustrating the conventional wire with a terminal; 
         FIG. 16B  is a sectional view illustrating the conventional wire with a terminal; 
         FIG. 16C  is a side view illustrating the conventional wire with a terminal; 
         FIG. 16D  is a sectional view illustrating the conventional wire with a terminal; and 
         FIG. 16E  is a sectional view illustrating the conventional wire with a terminal. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A wire with a terminal according to embodiments of the present invention will be described below with reference to  FIGS. 1 to 14 . A wire with a terminal  1  according to the present embodiment forms a wire harness disposed in an automobile, and is fitted and connected to various types of electronic devices mounted to an automobile and the like or to a counterpart connector mounted to another wire harness. The wire harness includes one or more wires W, a terminal fitting  2  crimped to a terminal of the wire W, and a connector, not illustrated, for storing the terminal fitting  2 . The wire W includes a conductive core W 1 , and an insulating coating W 2  coating the core W 1 . The insulating coating W 2  at its end is peeled to expose the core W 1 , and the exposed core W 1  is electrically and mechanically connected to the terminal fitting  2 . 
     The terminal fitting  2  ( 2 A,  2 B, and  2 C) is a female terminal fitting formed by a punching process and a bending process to a conductive plate. The terminal fitting  2  includes an electric contact part  3  in a rectangular cylindrical shape connected to a counterpart terminal (male terminal) from front (from left in  FIG. 1 ), a wire connection part  4  mounted at the back of the electric contact part  3  and connected to the wire W, and a coupling part  5  coupling these parts, the coupling part  5  having a cross-section of a reversed C shape. Here, the front of the terminal fitting  2  ( 2 A,  2 B,  2 C) typically corresponds to the side where the counterpart terminal is located when the terminal fitting  2  is connected to the counterpart terminal. In other words, the front of the terminal fitting  2  corresponds to a tip end side of the core W 1  exposed from the insulating coating W 2  in the extending direction of the wire W (see  FIG. 1 ). On the other hand, the back of the terminal fitting  2  ( 2 A,  2 B,  2 C) typically corresponds to the side opposite to the side where the counterpart terminal is located when the terminal fitting  2  is connected to the counterpart terminal. In other words, the back of the terminal fitting  2  corresponds to a base end side of the core W 1  exposed from the insulating coating W 2  in the extending direction of the wire W (see  FIG. 1 ). 
     The electric contact part  3  is formed into a rectangular cylinder having an upper wall part  31 , a pair of side walls  32 , and a bottom wall  33 , and is continuously formed with a bottom plate  51  and a pair of side plates  52  of the coupling part  5 . A counterpart terminal is inserted into the electric contact part  3  of the terminal fitting  2  ( 2 A,  2 B,  2 C), and an elastic piece  34  holding the counterpart terminal with an inner surface of the electric contact part  3  is formed in the electric contact part  3 . The terminal fitting  2  ( 2 A,  2 B,  2 C) holds the counterpart terminal between the inner surface of the electric contact part  3  and the elastic piece  34  as described above, whereby the terminal fitting  2  and the counterpart terminal are electrically and mechanically connected to each other. The electric contact part  3  of the terminal fitting  2  ( 2 A,  2 B,  2 C) is provided with a stabilizer  35  projecting from one side (or two sides) of the side walls  32 . The stabilizer  35  is inserted into a guide groove in a connector housing (not illustrated) to be guided, whereby the terminal fitting  2  can be inserted into the connector housing in a predetermined direction. 
     The wire connection part  4  has a barrel piece  41  continuous with the bottom plate  51  and the pair of side plates  52  of the coupling part  5 . The barrel piece  41  has a cross-section of an almost U shape open to one side (open upward in the figure) before it is caulked (before it is crimped as illustrated in  FIG. 2  or the like). The barrel piece  104  is caulked while covering a tip end of the wire W, thereby being crimped to the wire W. A saw-like serration part  42  for holding the core W 1  of the wire W is formed on an inner surface of the barrel piece  41  of the terminal fitting  2  ( 2 A,  2 B,  2 C). The barrel piece  41  also has a sheet-type holding part  43  extending posterior to the serration part  42 . The holding part  43  is configured to hold the insulating coating W 2  of the wire W. 
     A water stop part  44  for closing a gap with the wire W is formed on the inner surface of the barrel piece  41  of the terminal fitting  2  ( 2 A,  2 B,  2 C) except for the serration part  42 . The terminal fitting  2  ( 2 A,  2 B,  2 C) is also provided with a front water stop part  45  for closing the inside of the barrel piece  41  that is deformed into a cylinder, the front water stop part  45  being mounted anterior to the core W 1  of the wire W in the state in which the barrel piece  41  is caulked. The front water stop part  45  may be formed such that the water stop part  44  projects forward by the caulking of the barrel piece  41 , or may be formed by filling a water stop material after the caulking of the barrel piece  41 . 
     First Embodiment 
     Next, the terminal fitting  2 A according to a first embodiment will be described in detail with reference to  FIGS. 1 to 5 . The wire connection part  4  in the terminal fitting  2 A is provided with a projecting piece  46  projecting forward (toward the electric contact part  3 ) from the vicinity of one edge of the U-shaped barrel piece  41  as illustrated in  FIG. 2 . As illustrated in  FIGS. 1 and 3 , the projecting piece  46  is caulked simultaneous with the caulking of the barrel piece  41  or after the barrel piece  41  is caulked. The projecting piece  46  is thus deformed toward the core W 1  of the wire W to be in contact with the tip end of the core W 1 . More specifically, the projecting piece  46  has a function as a positioning unit to position the wire W in the longitudinal direction by contacting to the tip end of the core W 1 . In other words, the positioning unit is formed by deforming the projecting piece  46 , which projects forward at the circumferential end of the barrel piece  41 , toward the core W 1  by caulking. The projecting piece  46  is formed anterior to the serration part  42  for positioning the tip end of the core W 1 . The projecting piece  46  is not limited to the one deformed toward the core W 1 . The projecting piece  46  may be formed to extend forward from the tip end of the core W 1  in such a manner that its inner surface is in contact with the tip end of the core W 1  as illustrated in  FIG. 4 . 
     A manufacturing procedure of the wire with a terminal  1  as described above will now be described. As illustrated in  FIG. 5 , a water stop material applying process, a wire set process, and a barrel piece caulking process are sequentially performed in this order to a plurality of terminal fittings  2 A, which are formed by performing a punching process and a bending process to a plate and are connected in a chain, and which are carried from an upstream side (left in  FIG. 5 ) to a downstream side (right in  FIG. 5 ). The water stop material applying process is performed by using a water stop material applying device M 1  having an application head H 1  that applies a water stop material onto an inner surface of the barrel piece  41 . The water stop material applying device M 1  lowers the application head H 1  toward the inner surface of the barrel piece  41 , and then, supplies a water stop material to the application head H 1  through a tube T. Thus, the water stop material applying device M 1  applies the water stop material onto the inner surface of the barrel piece  41 , whereby the water stop part  44  is formed. Appropriate materials such as butyl rubber, silicon rubber, epoxy resin, or urethane resin can be used as the water stop material to be applied. More specifically, a liquid water stop material is applied on the inner surface of the barrel piece  41  to form the water stop part  44 . 
     After the water stop part  44  is formed on the inner surface of the barrel piece  41  as described above, a wire supply device (not illustrated) sets the tip end of the wire W in the barrel piece  41 . Subsequently, a crimp device (not illustrated) caulks the barrel piece  41  to crimp the terminal fitting  2 A and the wire W. In other words, the barrel piece  41  is caulked to be deformed into a cylinder to cover the tip end of the wire W to cause the water stop part  44  to be in close contact with the wire W. Thereafter, the terminal fittings  2 A in a chain are separated, whereby the wire with a terminal  1  in which the terminal fitting  2 A is crimped to the terminal of the wire W is manufactured. 
     Second Embodiment 
     Next, a terminal fitting  2 B according to a second embodiment will be described in detail with reference to  FIGS. 6 to 10 . A wire connection part  4  in the terminal fitting  2 B is provided with a projecting piece  47  projecting forward (toward the electric contact part  3 ) from the vicinity of one edge of a water stop part  44  formed on a U-shaped barrel piece  41  as illustrated in  FIG. 7 . As illustrated in  FIGS. 6 and 8 , the projecting piece  47  is caulked simultaneous with the caulking of the barrel piece  41  or after the barrel piece  41  is caulked. The projecting piece  47  is thus deformed toward a core W 1  of a wire W to be in contact with the tip end of the core W 1 . More specifically, the projecting piece  47  has a function as a positioning unit to position the wire W in the longitudinal direction by contacting to the tip end of the core W 1 . In other words, the positioning unit is formed by deforming the projecting piece  47 , which projects forward at the circumferential end of the water stop part  44 , toward the core W 1  by caulking. The projecting piece  47  is formed anterior to a serration part  42  for positioning the tip end of the core W 1 . 
     A manufacturing procedure of the wire with a terminal  1  as described above will now be described. As illustrated in  FIG. 9 , a water stop material attaching process, a wire set process, and a barrel piece caulking process are sequentially performed to a plurality of terminal fittings  2 B, which are formed by performing a punching process and a bending process to a plate and are connected in a chain, and which are carried from an upstream side (left in  FIG. 9 ) to a downstream side (right in  FIG. 9 ). The water stop material attaching process is performed by using a water stop material attaching device M 2  having an attachment head H 2  for attaching a water stop sheet  44 A onto the inner surface of the barrel piece  41 . The water stop material attaching device M 2  holds the water stop sheet  44 A with the attachment head H 2  by, for example, sucking, and then lowers the attachment head H 2  toward the inner surface of the barrel piece  41  to press the attachment head H 2  against the inner surface of the barrel piece  41 . Thus, the water stop material attaching device M 2  attaches the water stop sheet  44 A on the inner surface of the barrel piece  41 , whereby the water stop part  44  is formed. More specifically, the water stop material attaching device M 2  attaches the water stop sheet  44 A that is a sheet-type water stop material onto the inner surface of the barrel piece  41  to form the water stop part  44 . 
     An appropriate material formed into a sheet, such as butyl rubber, silicon rubber, epoxy resin, or urethane resin, can be used as the water stop sheet  44 A to be attached. It is preferable that an adhesive agent is applied onto the back surface of the water stop sheet  44 A facing the inner surface of the barrel piece  41 . An adhesive agent may be applied on the front surface of the water stop sheet  44 A facing the wire W. As illustrated in  FIGS. 10A and 10B , a projection  41 A may be formed on the bottom surface of the barrel piece  41 , and the projection  41 A may be inserted into an insertion hole  44 B ( FIG. 10A ) formed on the water stop sheet  44 A to position the water stop sheet  44 A. Alternatively, the projection  41 A may be inserted into a cutout  44 C ( FIG. 10B ) formed on the water stop sheet  44 A to position the water stop sheet  44 A. 
     After the water stop part  44  is formed on the inner surface of the barrel piece  41  as described above, a wire supply device (not illustrated) sets the tip end of the wire W in the barrel piece  41 . Then, a crimp device (not illustrated) caulks the barrel piece  41  to crimp the terminal fitting  2 B and the wire W. In other words, the barrel piece  41  is caulked to be deformed into a cylinder to cover the tip end of the wire W to cause the water stop part  44  to be in close contact with the wire W. Thereafter, the terminal fittings  2 B in a chain are separated, whereby the wire with a terminal  1  in which the terminal fitting  2 B is crimped to the terminal of the wire W is manufactured. 
     Third Embodiment 
     Next, a terminal fitting  2 C according to a third embodiment will be described in detail with reference to  FIGS. 11 to 14 . In the state in which a barrel piece  41  is crimped to a wire W by caulking, a small-diameter part  48 , which is deformed toward a core W 1  of the wire W by caulking, is formed at a front end of the barrel piece  41  of a wire connection part  4  in the terminal fitting  2 C as illustrated in  FIGS. 11 and 13 . The small-diameter part  48  is configured to be in contact with the tip end of the core W 1 . More specifically, the small-diameter part  48  has a function as a positioning unit to position the wire W in the longitudinal direction by contacting to the tip end of the core W 1 . In other words, the positioning unit is formed by deforming the small-diameter part  48  at the front end of the barrel piece  41  toward the core W 1  by caulking. The small-diameter part  48  is formed anterior to a serration part  42  for positioning the tip end of the core W 1 . As illustrated in  FIG. 13B , the diameter of the small-diameter part  48  is small, so that a water stop part  44  and a front water stop part  45  are crushed and, therefore, the inside of the barrel piece  41  is closed. It should be noted that the small-diameter part  48  is not limited to the one formed at the end of the barrel piece  41 . The small-diameter part  48  may be formed by caulking the bottom wall of the barrel piece  41  as illustrated in  FIGS. 14A and 14B . 
     In the manufacturing procedure of the wire with a terminal  1  described above, the water stop material applying process or the water stop material attaching process, the wire set process, and the barrel piece caulking process are sequentially performed in this order as in the first embodiment and the second embodiment. When a crimp device (not illustrated) caulks the barrel piece  41  to crimp a terminal fitting  2 A and the wire W in the barrel piece caulking process, the crimp device more strongly caulks the front end of the barrel piece  41  to form the small-diameter part  48 . Thereafter, the terminal fittings  2 C in a chain are separated, whereby the wire with a terminal  1  in which the terminal fitting  2 C is crimped to the terminal of the wire W is manufactured. 
     According to the above present embodiments, the tip end of the core W 1  of the wire W is positioned by the projecting piece  46  or  47  or the small-diameter part  48  formed anterior to the serration part  42 . This configuration can prevent the positional deviation of the wire W. Accordingly, the core W 1  and the serration part  42  can surely be connected without enhancing the positioning precision of the wire W more than necessary in the crimping operation. Further, the gap between the barrel piece  41  and the wire W is closed by the water stop part  44 . The closed gap can prevent water or the like from entering the connection part between the core W 1  and the serration part  42 , whereby corrosion of the terminal fitting  2  and the core W 1  can be prevented. In addition, the projecting piece  46  or  47  or the small-diameter part  48  is deformed by caulking. Accordingly, deformation of the coupling part  5  is not required, whereby the strength of the terminal fitting  2  can be ensured. 
     As described above, the terminal fitting includes the positioning unit mounted anterior to the serration part for positioning the tip end of the core of the wire. According to the above configuration, the positional deviation of the wire can be prevented. Therefore, the core and the serration part can surely be connected without enhancing the positioning precision of the wire more than necessary in the crimping operation. The gap between the barrel piece and the wire is closed by the water stop part in the terminal fitting. The closed gap can prevent water or the like from entering the connection part between the core and the serration part, whereby corrosion of the terminal fitting and the core can be prevented. 
     In the terminal fitting, the positioning unit is formed by deforming a projecting piece which projects forward at a circumferential end of the barrel piece or the water stop part, or by deforming a front end of the barrel piece. With this configuration, an operator can caulk the barrel piece while confirming the tip end of the core during the crimping operation, whereby the positional deviation of the wire can more surely be prevented. In addition, the strength of the terminal fitting can be ensured without entailing deterioration in strength of the coupling part, by deforming the front end of the projecting piece or the barrel piece by caulking, not by deforming the coupling part together with the barrel piece as in the conventional terminal fitting. 
     In the present invention, the position of the tip end of the core is positioned by the positioning unit. Accordingly, the present invention can prevent the positional deviation of the wire, can enhance working efficiency for the crimping operation, and can prevent connection failure between the core and the serration part. According to the present invention, the connection part between the core and the serration part is waterproofed by the water stop part, whereby corrosion of the terminal fitting and the core can be prevented. 
     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. 
     In the above embodiments, a female terminal is illustrated as an example of the terminal fitting  2 . However, the terminal fitting according to the present invention is not limited to a female terminal, but may be a male terminal. 
     The above embodiments describe the method of applying a water stop material by using the water stop material applying device M 1 , and the method of attaching the water stop sheet  44 A by using the water stop material attaching device M 2 , as the method of forming the water stop part  44 . However, it is not limited thereto. For example, a liquid water stop material may be ejected from an ink jet head and applied onto an inner surface of the barrel piece  41 , a water stop material may be applied by using a pen-type application tool impregnated with the water stop material on its tip end, or the barrel piece  41  in which the serration part  42  is masked is dipped into a liquid water stop material to apply the water stop material. 
     The range where the water stop part  44  is formed on the inner surface of the barrel piece  41  may be the entire inner surface of the barrel piece  41  except for the serration part  42 , or may be only one of a front side and a back side of the barrel piece  41 . The range can appropriately be set.