Patent Publication Number: US-7591652-B2

Title: Electrical connector and method of producing the same

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to an electrical connector and a method of producing the same. More specifically, the present invention relates to an electrical connector having terminals integrally formed with and held by a housing. 
   In Patent Reference, an electrical connector having terminals integrally formed with and held by the housing is disclosed. When the electrical connector is produced, all surfaces of the terminals having a carrier that are integrally formed with the carrier are plated. Further, terminal portions and the housing are integrally formed, so that the terminals are held by the housing. Then, the electrical connector is obtained by separating the carrier. 
   Patent Reference: Japanese Patent Publication No. 9-259989 
   In the electrical connector disclosed in Patent Reference, all surfaces of the terminals having the carrier are plated before the terminal portions and the housing are integrally formed. At this time, at least all the surfaces of the terminal portions are plated. When the terminal portions are integrally formed with and held by the housing, the plated surfaces of the terminals contact with the housing. 
   When a resin to form the housing is contracted after the terminal portions are integrally formed with the housing, there may be a slight gap between the housing and the terminals. Further, when a size or a height of the connector is reduced, a contact between the terminals and the housing may become poor. Accordingly, a gap may be formed between the housing and the terminals. 
   When a gap is formed between the housing and the terminals, and when the electrical connector is mounted to a circuit board, a solder and a flux may reach the gap described above from connection portions with respect to the circuit board of the terminals due to a surface tension. That is, the flux may rise when soldered. In the electrical connector disclosed in Patent Reference, the flux is likely to rise when soldered because all surfaces of the terminals are plated. Accordingly, when the solder and the flux enter the gap between the housing and the terminals and reach the contact portions of the terminals, the contact between the terminals and the terminals of the mating connector may become poor, thereby reducing reliability of the contact. In a small and short electrical connector, a distance between the connection portions and the contact portions is short. Accordingly, the solder and the flux may easily reach the contact portions of the terminals. Consequently, the gap between the housing and the terminals may be enlarged, thereby reducing a retention force of the housing to hold the terminals. 
   Further, in the electrical connector disclosed in Patent Reference, the terminals are plated after being bent to form. Accordingly, in case the terminals collide with each other or surroundings, the terminals are likely to be pressured and deformed. Further, when the housing is integrally formed with the terminals, a material of the housing or residue and dust generated by plating may adhere to the terminals. Consequently, the contact of the terminals may become poor. 
   In view of the problems described above, an object of the present invention is to provide an electrical connector and a method of producing the same. The electrical connector has terminals integrally formed with and held by a housing. Further, in the electrical connector, the flux is less likely to rise when soldered. 
   SUMMARY OF THE INVENTION 
   In order to achieve the above objects, in the present invention, when an electrical connector is produced, terminal portions having a carrier are integrally formed with a housing. The housing holds the terminal portions. Further, the terminal portions are separated from the carrier, so that the terminal portions become independent terminals. 
   In the electrical connector, each of the terminals is provided with a first surface and a second surface. The first surface does not contact with the housing and is plated, while the second surface contacts with the housing and is not plated. 
   In the electrical connector, the contact portion and the connection portion are provided on the first surface that is exposed and plated. Accordingly, when the electrical connector is used, the contact portions and the connection portions have good electrical contact characteristic and adhesive characteristic to solder. Further, a gap formed between the housing and the contact surfaces is reduced since the second surface adjacent to the housing is not plated. Accordingly, when soldered, rising of the flux to the gap is likely to be prevented. 
   In the method of producing the electrical connector in the present invention, at least the terminal portions are plated after the terminal portions and the housing are integrally formed. Then, the electrical connector may be produced by separating the terminal portions from the carrier. 
   In the present invention, the plating includes plating to make an electrical contact and soldering easier. For example, the plating may include gold plating or silver plating. The plating does not include base plating or corrosion proof plating such as nickel plating. Accordingly, in the present invention, base plating or corrosion proof plating may be provided on the contact surfaces of the terminals with respect to the housing. 
   As described above, in the electrical connector, the terminal is provided with the first surface and the second surface. The first surface does not contact with the housing and is plated, while the second surface contacts with the housing and is not plated. Accordingly, the contact portions and the connection portions provided on the first surfaces have good electrical contact characteristic and adhesive characteristic to solder. The second surfaces that contact with the housing are not plated. Accordingly, the solder and the flux are not likely to enter the gap formed on the contact surfaces between the terminals and the housing. 
   Further, in the method of producing the electrical connector in the present invention, the electrical connector may be obtained by separating the carrier after the terminal portions and the housing are integrally formed and the carrier and the terminals are plated. Specifically, in the terminal structure that arranges a pair of the terminals in rows in parallel, all terminals may be plated at once after the terminal portions and the housing are integrally formed. Accordingly, the electrical connector may be produced easier than when the terminal portions and the housing are integrally formed after plating the terminal rows that are facing each other. 
   In the present invention, the terminals are plated after the terminal portions and the housing are integrally formed. Accordingly, the terminals are not likely to be deformed when plated. Further, a material of the housing or residue and dust yielded by plating may be cleaned and removed during a production process. Accordingly, a poor contact of the terminals due to an adherence of dust may be prevented. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a vertical sectional view showing an electrical connector of the present invention; and 
       FIG. 2  is a plan view showing a production process of the electrical connector. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings.  FIG. 1  is a vertical sectional view showing an electrical connector  10  of an embodiment in the present invention.  FIG. 2  is a plan view showing a production process of the electrical connector  10  of  FIG. 1 . 
   As shown in  FIG. 1 , the electrical connector  10  is in a box shape having a bottom and includes a housing  11  formed by molding an insulating resin. The housing  11  is provided with a depressed portion  12  to receive a mating connector (not shown) therein. The electrical connector  10  extends in a direction perpendicular to a sheet surface of  FIG. 1 , and has a long rectangular shape in a plan view as shown in  FIG. 2 . Further, the housing  11  is provided with a pair of sidewalls  13 , edge walls  14 , and a bottom wall  15 . The sidewalls  13  are in a long rectangular planar shape and extend in a longitudinal direction. The edge walls  14  connect end portions of the sidewalls  13 . The bottom wall  15  connects lower edges of the sidewalls  13  and lower edges of the edge walls  14 . 
   In the embodiment, each of the sidewalls  13  of the housing  11  is provided with a plurality of terminals  20  at a specific interval in a longitudinal direction thereof. A plurality of terminals  20  and the housing  11  are integrally formed, and the housing  11  holds a plurality of terminals  20 . As shown in  FIG. 1 , a pair of the sidewalls  13  facing each other holds a plurality of terminals  20 . Each of the terminals  20  has a symmetrical shape and is arranged symmetrically. 
   In the embodiment, a thin flat metal band is punched out and bent toward a plate thickness direction thereof to form the terminal  20 . As shown in  FIG. 1 , the terminal  20  comprises a contact portion  21 , an introduction portion  22 , a retained portion  23 , and a connection portion  24 . The contact portion  21  is closely attached to an inner surface of the sidewall  13  of the housing  11  and upright. The introduction portion  22  is bent in an inverted U-shape toward an edge portion of the electrical connector  10  to form a curve portion above the contact portion  21 . The retained portion  23  is bent in an L-shape below the contact portion  21  and held by the housing  11 . The connection portion  24  extends from the retained portion  23  and protrudes to an outside of the housing  11 . 
   In the embodiment, exposed plate surfaces of the contact portions  21  of the terminals  20  are flush with or slightly protrude from inner surfaces of the sidewalls  13  of the housing  11 . That is, the contact portions  21  are buried at least partially in the sidewalls  13  in a plate surface direction. 
   In the embodiment, the introduction portion  22  includes an inner curved surface  22 A. The inner curved surfaces  22 A adhere to inner surfaces of an upper edge of the sidewalls  13  and are buried inside of the side walls  13 . The inner curved surfaces  22 A may easily guide and introduce terminals of the mating connector. Edge portions  22 B are securely held by the sidewalls  13  of the housing  11 . The retained portions  23  are completely buried in the housing  11  and held firmly by the housing  11 . 
   In the embodiment, the connection portions  24  extend outside of the housing  11  and are bent in a crank shape outside of the housing  11 . Distal portions  24 A of the connection portions  24  are substantially flush with or situated slightly downward of a bottom face of the housing  11 . When the electrical connector  10  is mounted to a circuit board (not shown), the distal portions  24 A of the connection portions  24  contact with corresponding circuit portions of the circuit board and are connected to the circuit portion with solder. 
   In the embodiment, the electrical connector  10  is provided with plated layers  25  on exposed surfaces of the terminals  20 . The plated layer  25  comprises a plated layer  25 A provided on an exposed surface of the contact portion  21  and a part of the introduction portion  22  and a plated layer  25 B provided on a surface of the connection portion  24 . The terminals  20  electrically contact well with the terminals of the mating connector through the contact portions  21  and the plated layers  25 A of the introduction portions  22 . The plated layers  25 B of the connection portions  24  make a soldering well. The surfaces of the terminals  20  adjacent to the housing  11  are not plated. 
   Next, a method of producing the electrical connector  10  will be explained with reference to  FIG. 2 . As shown in  FIG. 2 , terminal members  30  are integrated with the housing  11 . The terminal member  30  includes a carrier portion  31  and a terminal portion  32 . The terminal member  30  is made as a long metal plate formed by punching out and is rolled. The terminal member  30  is pulled out from a roll when used. 
   As shown in  FIG. 2 , two terminal members  30  are symmetrically situated. Each of the terminal members  30  is provided with a carrier portion  31  in a flat band shape extending in a longitudinal direction with respect to the terminal members  30 . The carrier portion  31  is provided with a plurality of engagement holes  31 A at a specific interval in a longitudinal direction thereof. The engagement holes  31 A engage with transport nails of a transport device. Further, the terminal members  30  are transported to the longitudinal direction thereof intermittently during positioning and a production process. Terminal portions  32  are provided in a perpendicular direction with respect to the longitudinal direction from inner edge portions of the carrier portions  31  at an interval of distances  33 . The terminal portions  32  are formed per a group of the number to be held by each of the sidewalls  13  of the connector. 
   In the embodiment, the terminal portions  32  stretch from the carrier portions  31 . As shown in  FIG. 1 , the terminal portion  32  comprises the connection portion  24 , the retained portion  23  formed flexibly, the contact portion  21  standing upright, and the introduction portion  22  in an inverted U character shape. As shown in  FIG. 2 , the terminal portions  32  extending from the terminal members  30  are integrally formed with the housing  11  along the longitudinal direction thereof. Further, as shown in  FIG. 1 , the retained portions  23  of the terminal portions  32 , the contact portions  21 , and the introduction portions  22  are integrally formed with the housing  11 . 
   Accordingly, a plurality of the housings  10  is integrally formed with the terminal members  30 . Further, a plurality of the housings is immersed in a plating bath (not shown) and plated in a state that the terminal portions  32  are held. Both the carriers  31  and the terminal portions  32  may be plated, or only the terminal portions  32  may be plated. When plated, the plated layers are formed only in the portions of the terminal portions  32  that are exposed from the housing  11 , but not in the portions that are adjacent to the housing  11 . Further, specific positions of the terminal portions  32  are cut to separate the carrier portions  31  to obtain the connector  10  shown in  FIG. 1 . Accordingly, in the electrical connector  10 , the plated layers  25  are formed only in the surfaces of the terminals  20  exposed from the housing  11 . The plated layer  25  includes the plated layer  25 A of the contact portion  21  and the introduction portion  22  and the plated layer  25 B of the connection portion  24 . 
   In the embodiment, when the electrical connector  10  is mounted to the circuit board, a solder may be applied to the plated layers  25 B of the connection portions  24  with ease. Further, when the electrical connector  10  is fitted to the mating connector, the plated layers  25 A of the contact portions  21  improve an electrical contact with the mating connector. Even though there is a gap between the housing  11  and the terminals  20 , the terminals  20  that are situated in the gap are not plated. Accordingly, when a solder is applied to the connection portions  24 , the solder or a flux are not likely to enter the gap. 
   The present invention is not limited to the present embodiment, and may be modified. A shape and a position of the terminal  20  may be changed. The terminal  20  only needs to be integrally formed with and held by the housing  10  and has both an exposed portion and a non-exposed portion. A configuration of the electrical connector  10  is not limited and may be different. 
   Further, there are many ways to plate. The area except for an area adjacent to the housing  10  of the terminals  20  may be plated before the terminals  20  and the housing  10  are integrally formed.