Patent Publication Number: US-10777926-B2

Title: Multi-contact terminal

Description:
BACKGROUND 
     Field of the Invention 
     The present invention relates to a multi-contact terminal. 
     Related Art 
     Japanese Unexamined Patent Publication No. 2015-99698 discloses a multi-contact terminal to be brought into contact with a mating terminal on many contact points and is used in an electric vehicle or the like. This terminal is configured such that cantilevered resilient contact pieces extend forward from the front end edge of an angular tube and are folded rearward into the angular tube for contacting the outer peripheral surface of a rod-like round pin having a circular cross-section. 
     Associated with an increase of a current in a power supply path, a demand for suppressing the amount of heat generation of a terminal is being increased. It is considered to increase a plate thickness of the terminal to reduce electrical resistance, but the resilient contact pieces are enlarged to cause a problem of enlarging the terminal itself if the plate thickness is increased. 
     Further, if a wire becomes thicker, a connected state to the mating terminal may become unstable due to vibration received from the wire. Thus, a more stable connected state is desired. 
     The invention was completed on the basis of the above situation and an object thereof is to provide a multi-contact terminal configured to bring resilient contact pieces into contact with a mating terminal, hardly inclined even when receiving vibration from a wire and capable of suppressing the amount of heat generation. 
     SUMMARY 
     A multi-contact terminal in accordance with an embodiment of the invention includes a polygonal tube with a plurality of side walls. Front resilient contact pieces extend from front ends of the side walls in a connecting direction to a mating terminal and are folded rearward at front folds. The front resilient contact pieces resiliently contacting an outer peripheral surface of the mating terminal inside the polygonal tubeRear resilient contact pieces extend from rear ends of the side walls in the connecting direction and are folded forward at rear folds. The rear resilient contact pieces resiliently contact the outer peripheral surface of the mating terminal inside the polygon tube. The polygonal tube, the front resilient contact pieces and the rear resilient contact pieces are integral with one another. 
     According to the above configuration, the multi-contact terminal includes the front and rear resilient contact pieces on front and rear ends of the side walls of the polygonal tube with respect to the connecting direction to the mating terminal. Thus, the multi-contact terminal can contact the mating terminal at positions different in a length direction, i.e. the connecting direction. Specifically, a posture relative to the mating terminal is maintained more easily as compared to a conventional configuration in which resilient contact pieces are provided on side walls only on one end. Thus, the multi-contact terminal is less likely to incline during a connection operation to the mating terminal or upon receiving vibration from a wire so that a connected state can be maintained stably. Further, there are more contact points with the mating terminal than before. Thus, contact resistance decreases, and the amount of heat generation of the terminals can be suppressed. 
     The front and rear resilient contact pieces may have the same dimensions and the same shape, and the front resilient contact pieces or the rear resilient contact pieces may be disposed at positions different in the connecting direction. When fitting the terminals to each other, insertion resistance is largest when the mating terminal thrusts itself between the resilient contact pieces of the multi-contact terminal. According to the above configuration, since the front resilient contact pieces and/or the rear resilient contact pieces contact the mating terminal at the positions different in the length direction, i.e. the connecting direction. Thus, insertion resistance during a fitting operation can be reduced as compared to a configuration in which the resilient contact pieces contact the mating terminal at the same position. In addition, since the front and rear resilient contact pieces have the same dimensions and the same shape, a contact pressure of each resilient contact piece with the mating terminal can be made equal. 
     The tube may be provided with forward expanding portions adjacent to base end parts of the front resilient contact pieces and extending along an extending direction of the front resilient contact pieces. By adopting this configuration, the rigidity of the base end parts of the front resilient contact pieces is increased by the forward expanding portions. Therefore the deformation of the base end parts of the front resilient contact pieces by being pressed by the mating terminal is suppressed when the mating terminal is inserted. 
     The forward expanding portions may extend farther forward than the front folded portions. By adopting this configuration, even if the mating terminal or a device butts against the multi-contact terminal from the front, the front folded portions are protected by the forward expanding portions extending forward. Thus, the deformation of the front resilient contact pieces can be suppressed. 
     The tube may be formed by fixing end edges of a plate-like member bent into a polygonal tube shape to each other. By adopting this configuration, the multi-contact terminal can be produced easily. 
     According to the present invention, it is possible to obtain a multi-contact terminal hardly inclined even when receiving vibration from a wire and capable of suppressing the amount of heat generation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view of a multi-contact terminal of one embodiment. 
         FIG. 2  is a section of the multi-contact terminal. 
         FIG. 3  is a section showing a state where the multi-contact terminal is connected to a mating terminal. 
         FIG. 4  is a front view of the multi-contact terminal. 
         FIG. 5  is a development of the multi-contact terminal. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, one embodiment is described in detail with reference to  FIGS. 1 to 5 . 
     A multi-contact terminal of this embodiment is a large current terminal used in a power supply line or the like of an electric vehicle, a hybrid vehicle or the like. As shown in  FIG. 3 , the multi-contact terminal is a female terminal  20  into which a mating male terminal  10  in the form of a round rod having a uniform diameter is fit, and is configured such that resilient contact pieces  30 ,  40  of the female terminal  20  are brought into contact with the outer peripheral surface of the male terminal  10 . In the following description, a connecting direction X to the mating terminal is referred to as a forward direction and upper and lower sides of  FIG. 2  are referred to as upper and lower sides in each constituent member. 
     The male terminal  10  is formed of a metal material excellent in conductivity, such as copper alloy. One end of the male terminal  10  is connected to an unillustrated wire and the other end thereof serves as a connecting portion  11  in the form of a round rod (see  FIG. 3 ). 
     The female terminal  20  is formed from a metal material excellent in conductivity, such as copper alloy, that is press-worked into a predetermined shape. As shown in  FIGS. 1 and 2 , a body  21  to be connected to the connecting portion  11  of the male terminal  10  and a wire connecting portion  52  to be connected to a wire  60  are connected one after the other via a link  51 . 
     The body  21  includes an octagonal tube  23  with eight front resilient contact pieces  30  integrally extending forward from an end edge on a front of the tube  23  and folded rearwardly and inwardly, and six rear resilient contact pieces  40  integrally extending rearward from an end edge on a rear of the tube  23  and folded forwardly and inwardly. 
     The tube  23  is formed into a substantially octagonal tube shape with eight side walls  24  by bending a flat metal plate stamped into a development shape, as shown in  FIG. 5 , by a press forming machine and preventing both end parts in a bending direction from being opened by a locking portion  26 . The eight side walls are denoted successively by  24 A,  24 B,  24 C,  24 D,  24 E,  24 F,  24 G and  24 H from a lower side of  FIG. 5 , and denoted by  24  when being not distinguished. 
     The locking portion  26  is composed of a locking hole  28  provided in a locking piece  27  extending from the side wall  24 A on one end in the bending direction of the metal plate and a locking protrusion  29  projecting radially out of the tube  23  on the side wall  24 H on the other end. The locking hole  28  is at a position straddling over a bending line indicated by a broken line in  FIG. 5 . Further, the locking protrusion  29  is formed by cutting and raising an end part of the side wall  24 H radially outward of the angular tube  23  (see  FIG. 1 ). 
     As shown in  FIG. 5 , the angular tube  23  of this embodiment is configured by alternately shifting adjacent side walls  24 A to  24 H in a front-rear direction. Specifically, the side walls  24 A,  24 C,  24 E and  24 G are first side walls  241  disposed near a rear end (near a right end of  FIG. 5 ), and the side walls  24 B,  24 D,  24 F and  24 H are second side walls  242  disposed near a front end (near a left end of  FIG. 5 ). The first side walls  241  and the second side walls  242  have equal length (lateral dimension in  FIG. 5 ) and width (vertical dimension in  FIG. 5 ). 
     The link  51  extends continuously rearward from the rear end of the side walls  24 C,  24 D and  24 E, and the wire connecting portion  52  is a flat plate that extends rearward from the rear end of the link  51  (see  FIGS. 1 and 5 ). The wire  60  is welded to the wire connecting portion  52 . Further, the rear resilient contact piece  40  to be described later is cut out by a U-shaped slit  43  in an area of the link  51  connected to and behind the side wall  24 D. 
     The strip-like front resilient contact pieces  30  having a width about half the width of the side walls  24  extend forward from widthwise central parts of the front end edges of the respective side walls  24 A to  24 H of the polygonal tube  23 , and are folded inwardly and rearwardly of the tube  23  at front folded portions  31 . As shown in  FIG. 2 , rear parts of the front resilient contact pieces  30  extend obliquely inward to approach each other, and front contacts  32  bulge inward with arcuate cross-section at positions near the rear parts. The front contacts  32  are to be brought into contact with the connecting portion  11  of the male terminal  10 . 
     Further, the rear resilient contact pieces  40  are provided on the rear ends of the side walls  24  not provided with the link  51 , i.e. the side walls  24 A,  24 B,  24 F,  24 G and  24 H of the polygonal tube  23 , and on the side wall  24 D located in a middle, out of three side walls  24  provided with the link  51 . The rear resilient contact piece  40  of the side wall  24 D is cut out by providing the U-shaped cutting slit  43  in the link  51  as described above. The cutting slit  43  is at a position where the rear resilient contact piece  40  of the side wall  24 D is disposed at the same position as the rear resilient contact pieces  40  of the side walls  24 B,  24 F and  24 H in the front-rear direction. 
     The rear resilient contact pieces  40  have the same shape as the front resilient contact pieces  30 . Specifically, as shown in  FIG. 2 , front ends of the rear resilient contact pieces  40  extend obliquely in toward the front to approach each other, and rear contacts  42  bulge in with arcuate cross-sections at positions near tips that are to be brought into contact with the connecting portion  11  of the male terminal  10 . 
     The eight front resilient contact pieces  30  and the six rear resilient contact pieces  40  are shaped identically to have the same length in the front-rear direction, width, bent shape and the like. Specifically, front first resilient contact pieces  301  of the first side walls  241  (side walls  24 A,  24 C,  24 E and  24 G) are shifted rearward from front second resilient contact pieces  302  of the second side walls  242  ( 24 B,  24 D,  24 F and  24 H). Further, rear first resilient contact pieces  401  of the first side walls  241  (side walls  24 A,  24 C,  24 E and  24 G) are shifted rearward from rear second resilient contact pieces  402  of the second side walls  242  ( 24 B,  24 D,  24 F and  24 H). 
     Lengths of the front resilient contact pieces  30 , the rear resilient contact pieces  40  and the side walls  24  are set so that the tip parts of these front resilient contact pieces  30  and rear resilient contact pieces  40  do not touch each other. 
     Each side wall  24 A to  24 H is formed with one or two restricting protrusions  25  projecting radially inward by cutting and raising (see  FIG. 2 ). Specifically, each of the side walls  24 A,  24 B,  24 D,  24 F,  24 G and  24 H is provided with two of the restricting protrusions  25 , and each of the side walls  24 C,  24 E is provided with one restricting protrusion  25 . These restricting protrusions  25  restrict excessive deformation of the front resilient contact pieces  30  and the rear resilient contact pieces  40 . 
     The front restricting protrusion  25  or the one restricting protrusion  25  of one side wall  24  is provided somewhat in front of a position of the side wall  24  facing the front contact  32 . Further, the rear restricting protrusion  25  of one side wall  24  is provided somewhat behind a position of the side wall  24  facing the rear contact  42 . Specifically, the restricting protrusions  25  are at positions in contact with somewhat base ends of the contacts  32 ,  42  of the resilient contact pieces  30 ,  40 . 
     Forward expanding portions  35  extend forward at positions between base ends of adjacent ones of the front resilient contact pieces  30  in a developed state, shown in  FIG. 5  on the front of the polygonal tube  23 . Further, a forward expanding portion  35  is provided on a base end part of the front resilient contact piece  30  of the side wall  24 A on the side of the locking piece  27 . The locking piece  27  is integrated with this forward expanding portion  35  by extending to have a length equal to this forward expanding portion  35 . The front ends of these forward expanding portions  35  and the locking piece  27  are arranged on the same line. More particularly, lengths of front slits  36  provided between one forward expanding portion  35  and the adjacent front resilient contact pieces  30  differ on both sides of the forward expanding portion  35 , and a length of a first slit  361  located on the side of the first side wall  241  is longer than that of a second slit  362  located on the side of the second side wall  242 . By making the lengths of the slits  36  different in this way, the front resilient contact pieces  30  are located at positions different in the front-rear direction. 
     Similarly, rearward expanding portions  45  extend rearward at positions between extending end parts of adjacent rear resilient contact pieces  40  in the developed state shown in  FIG. 5  on the rear end of the polygonal tube  23 . Further, a rearward expanding portion  45  also is provided on a base end part of the rear resilient contact piece  40  of the side wall  24 A on the side of the locking piece  27 . The locking piece  27  is integrated with this rearward expanding portion  45  by extending to have a length equal to this rearward expanding portion  45 , but a corner part on a right-lower end of the locking piece  27  in  FIG. 5  is cut rectangularly to allow the rear resilient contact piece  40  of the side wall  24 H to escape. Note that no rearward expanding portion  45  is provided between the side walls  24 C and  24 D and between the side walls  24 D and  24 E, the link  51  extending from the side walls  24 C,  24 D and  24 E. The rear ends of a total of six rearward expanding portions  45  are arranged on the same line. The rear resilient contact pieces  40  also are located at positions different in the front-rear direction by making the lengths of rear slits  46  provided between adjacent ones of the rear resilient contact pieces  40  different. 
     The polygonal tube  23  is folded along the front-rear direction (along broken lines of  FIG. 5 ) on these expanding portions  35 ,  45  into a substantially octagonal tube shape (see  FIG. 4 ). 
     Note that the tips of the forward expanding portions  35  are more forward than the front folded portions  31  of the front resilient contact pieces  30  described above. Further, the tips of the rearward expanding portions  45  are more rearward than rear folded portions  41  of the rear resilient contact pieces  40  described above (see  FIG. 2 ). 
     The female terminal  20  of this embodiment is configured as described above. Next, a method for producing the female terminal  20  is described. 
     First, the respective resilient contact pieces  30 ,  40  are formed into a predetermined shape by bending (press-working) parts corresponding to the front resilient contact pieces  30  and the rear resilient contact pieces  40  of the metal plate stamped into a predetermined shape. The stamped metal plate is bent along the front-rear direction at positions corresponding to the forward expanding portions  35  and the rearward expanding portions  45  to form the polygonal tube  23 , the locking piece  27  is bent to cover the locking protrusion  29  formed on one end in the bending direction from an outer side, and the locking protrusion  29  is fit into the locking hole  28  for locking and preventing opening. Further, the link  51  is bent together with the polygonal tube  23 . In this way, the female terminal  20  having a predetermined shape shown in  FIG. 1  is obtained. 
     Next, a connecting operation of the male terminal  10  and the female terminal  20  and functions and effects are described. 
     First, when the connecting portion  11  of the male terminal  10  is inserted into the body  21  of the female terminal  20  having the wire  60  connected to the wire connecting portion  52  by resistance welding, the connecting portion  11  thrusts itself between the front contact portions  32  of two pairs of (four) front second resilient contact pieces  302  disposed diagonally while resiliently displacing the front second resilient contact pieces  302  and subsequently the front first resilient contact pieces  301  outward. 
     At this time, the forward expanding portions  35  extending from the polygonal tube  23  are provided between adjacent front resilient contact pieces  30  and rigidity is imparted to the base end parts of the respective front resilient contact pieces  30  by these forward expanding portions  35 . Thus, the base end parts of the front resilient contact pieces  30  are lifted and pushed to a back side of the polygonal tube  23  as the connecting portion  11  is inserted. 
     When the connecting portion  11  is inserted farther back, the connecting portion  11  successively thrusts itself between the front contact portions  32  of the front first resilient contact pieces  301 , between the rear contact portions  42  of the rear second resilient contact pieces  402  and between the rear contact portions  41  of the rear first resilient contact pieces  401 . 
     When the connecting portion  11  is inserted to a proper position in the polygonal tube  23 , the connecting portion  11  is successively sandwiched by four front second resilient contact pieces  302 , four front first resilient contact pieces  301 , four rear second resilient contact pieces  402  and two rear first resilient contact pieces  401 , with the resilient contact pieces being located at positions shifted from each other by 45°. In this way, the male and female terminals  10 ,  20  are connected electrically (see  FIG. 3 ). 
     As just described, since the resilient contact pieces are provided not only on the front, but also on the rear of the polygonal tube  23  according to the female terminal  20  of this embodiment, the resilient contact pieces can contact the connecting portion  11  of the male terminal  10  at the positions different in the front-rear direction, i.e. the connecting direction X and hold the connecting portion  11  in the body  21 . Since a posture of the female terminal  20  relative to the male terminal  10  easily is maintained as just described, the female terminal  20  is not inclined during a connecting operation or upon receiving vibration from the wire  60  and a connected state to the male terminal  10  can be maintained stably. 
     Further, there are more contact points with the male terminal  10  than before. Thus, contact resistance decreases, and the amount of heat generation of the female terminal  20  can be suppressed. Further, since a conductive path between the rear resilient contact pieces  40  and the wire  60  is shorter than that between the front resilient contact pieces  30  and the wire  60 , the amount of heat generation can be suppressed further. 
     Further, since the front resilient contact pieces  30  and the rear resilient contact pieces  40  are at the positions different in the connecting direction X, insertion resistance during a fitting operation becomes smaller and workability during a connecting operation is improved. In addition, all of the front resilient contact pieces  30  and the rear resilient contact pieces  40  have the same dimensions and the same shape. Thus, a contact pressure with the male terminal  10  can be made equal at all the contact portions  32 ,  42 . 
     Further, the polygonal tube  23  is provided with the forward expanding portions  35  adjacent to the base end parts of the front resilient contact pieces  30  and extending along an extending direction of the front resilient contact pieces  30 . Thus, the rigidity of the base end parts of the front resilient contact pieces  30  is increased and the base end parts of the front resilient contact pieces  30  will not be deformed by the male terminal  10  when the male terminal  10  is inserted. 
     Further, tips of the forward expanding portions  35  extend farther forward than the front folded portions  31  of the front resilient contact pieces  30 . Thus, the front folded portions  31  of the front resilient contact pieces  30  can be protected to prevent deformation even if a device butts against the female terminal  20  from the front or the male terminal  10  butts against the female terminal  20  in a direction different from the connecting direction X. 
     Further, since the female terminal  20  is formed by bending one metal plate and simply configured by locking the end parts in the bending direction to each other by the locking portion  26 , the female terminal  20  can be produced easily. Furthermore, since dimensions are easily controlled with bending, the contact pressure is adjusted easily. 
     The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments also are included in the scope of the invention. 
     Although the front resilient contact pieces  30  and the rear resilient contact pieces  40  are shifted in the front-rear direction in the above embodiment, these resilient contact pieces may be disposed at the same positions. 
     Although all of the front resilient contact pieces  30  and the rear resilient contact pieces  40  have the same dimensions and the same shape in the above embodiment, these resilient contact pieces may have different dimensions and/or different shapes. 
     Although the polygonal tube  23  of the female terminal  20  is prevented from being opened by locking the end edges in the bending direction to each other by the locking portion  26  in the above embodiment, this configuration is not always necessary. The opening may be prevented, for example, by welding or the like. 
     The expanding portions  35 ,  45  may not be provided. 
     The forward expanding portions  35  may not extend farther forward than the front folded portions  31 . 
     Although the resilient contact pieces  30 ,  40  extend from ends of all the side walls provided with the link  51  in the above embodiment, the resilient contact pieces  30 ,  40  may extend only from selected side wall(s). 
     Although the polygonal tube  23  having a substantially octagonal tube shape is shown in the above embodiment, the polygonal tube may have a polygonal tube shape having three or more angles. Note that the polygonal tube preferably has a polygonal shape having an even number of angles. 
     Although the contact portions  32 ,  42  of the resilient contact pieces  30 ,  40  are provided at two positions in the front-rear direction in the above embodiment, the contact portions  32 ,  42  may be provided at three or more positions in the front-rear direction. 
     Although the female terminal  20  and the wire  60  are connected by resistance welding in the above embodiment, a connection method is not limited to that of the above embodiment. For example, another connection method such as crimping or ultrasonic welding may be adopted. 
     LIST OF REFERENCE SIGNS 
     
         
           10  . . . male terminal (mating terminal) 
           20  . . . female terminal (multi-contact terminal) 
           23  . . . angular tube portion 
           24  . . . side wall 
           26  . . . locking portion 
           27  . . . locking piece 
           28  . . . locking hole 
           29  . . . locking protrusion 
           30  . . . front resilient contact piece 
           31  . . . front folded portion 
           35  . . . forward expanding portion 
           40  . . . rear resilient contact piece 
           41  . . . rear folded portion 
           45  . . . rearward expanding portion 
         X . . . connecting direction (forward)