Patent Publication Number: US-9431723-B2

Title: Female terminal fitting

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a female terminal fitting. 
     2. Description of the Related Art 
     A female terminal fitting disclosed in Japanese Unexamined Patent Publication No. 2003-243076 includes a tubular main body portion (called an “electrical contact portion” Japanese Unexamined Patent Publication No. 2003-243076) into which a male tab is to be inserted, and a resilient contact piece deflectably arranged in the main body portion and to be resiliently brought into contact with the male tab (called a “male terminal” in Japanese Unexamined Patent Publication No. 2003-243076) inserted into the main body portion. Further, a part of a side wall of the main body portion is cut and bent inwardly to prevent excessive deflection of the resilient contact piece, thereby forming an excessive deflection preventing piece. 
     In the above case, since a hole is made on the side wall as the excessive deflection preventing portion is formed, there has been a possibility that an external matter enters the main body portion through the hole. Particularly, since the above hole is located near a contact portion where the resilient contact piece comes into contact with the male tab, there has been a possibility that an external matter having entered through the hole adheres to the contact portion and electrical connection reliability might be impaired. 
     The present invention was completed based on the above situation and aims to provide a female terminal fitting capable of preventing excessive deflection of a resilient contact piece even without making a hole on a side wall of a main body portion. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a female terminal fitting with a tubular main body portion into which a mating male tab is to be inserted, and a resilient contact piece deflectably arranged in the main body portion, the resilient contact piece being resiliently deformed toward a base wall of the main body portion to resiliently come into contact with the male tab when the male tab is inserted into the main body portion, wherein an excessive deflection regulating piece for regulating excessive deflection of the resilient contact piece by coming into contact with the base wall of the main body portion is integrally provided to the resilient contact piece, an auxiliary spring piece cantilevered in a direction opposite to an inserting direction of the male tab is deflectably arranged in the main body portion, a spring force of the resilient contact piece is assisted by the contact of a free end part of the auxiliary spring piece with the resilient contact piece in a deflecting direction thereof, and the excessive deflection regulating pieces are formed by bending parts of the resilient contact piece protruding outwardly in a width direction toward the base wall of the main body portion and arranged to be proximate to opposite widthwise side edges of the free end part of the auxiliary spring piece and face and cover the opposite widthwise side edges. 
     Since the excessive deflection regulating piece for regulating the excessive deflection of the resilient contact piece is integrally provided to the resilient contact piece, the excessive deflection of the resilient contact piece can be prevented even without making a hole on a side wall of the main body portion. By the contact of the excessive deflection regulating pieces paired on the opposite widthwise sides of the resilient contact piece with the base wall, an excessive deflection movement of the resilient contact piece is stably regulated. Further, even if the auxiliary spring piece is going to excessively swing in the width direction, the excessive deflection regulating pieces come into contact with the auxiliary spring piece to regulate any further swing of the auxiliary spring piece. As a result, it is guaranteed that the auxiliary spring piece comes into contact with the resilient contact piece at a proper position. Further, a deflection movement of the auxiliary spring piece can be guided by the excessive deflection regulating pieces. The swing of the auxiliary spring piece is effectively suppressed at the free end part having a large swing amount when the auxiliary spring piece swings in the width direction. As a result, the stability of the deflection movement of the auxiliary spring piece is ensured. 
     A bent tip part of the excessive deflection regulating piece may contact the base wall of the main body portion. Accordingly, an excessive deflection amount of the resilient contact piece can be appropriately adjusted by adjusting a bending amount of the excessive deflection regulating piece. 
     The resilient contact piece may be cantilevered in an inserting direction of the male tab, and the excessive deflection regulating piece is provided on a free end part of the resilient contact piece. An excessive deflection movement of the resilient contact piece is more stably regulated by the contact of the excessive deflection regulating piece provided on the free end part of the resilient contact piece with the base wall. 
     The resilient contact piece may be wider on a base end part side than on the free end part. In this way, a resilient force reduction of the resilient contact piece is avoided and the free end part of the resilient contact piece does not largely protrude outwardly in the width direction due to the presence of the excessive deflection regulating piece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a bottom view of a main body portion in a female terminal fitting of one embodiment of the present invention. 
         FIG. 2  is a front view of the main body portion. 
         FIG. 3  is a front view in section of the main body portion. 
         FIG. 4  is a side view in section of the main body portion. 
         FIG. 5  is a view showing a state where excessive deflection of a resilient contact piece is regulated by excessive deflection regulating pieces when a male tab in a wrong posture is inserted into the main body portion. 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment of the present disclosure is described in detail with reference to  FIGS. 1 to 5 . A female terminal fitting  10  of this embodiment is formed such as by bending an electrically conductive metal plate and includes a main body portion  20  for receiving a mating male tab  90  and a resilient contact piece  21  deflectably arranged in the main body portion  20 . Note that although the female terminal fitting  10  includes a part to be connected to a wire behind the main body portion  20 , this part is neither described nor shown here. 
     The main body portion  20  is in the form of a rectangular tube penetrating in a front-back direction and, as shown in  FIGS. 2 and 3 , includes a base wall  22  extending substantially along a width direction, a pair of side walls  23  standing up from opposite side edges of the base wall  22  (opposite ends in the width direction) and a facing wall  24  bridged from the upper end of one of the both side walls  23  to the upper end of the other. A tab insertion space  25  into which the male tab  90  (see  FIG. 5 ) is to be inserted is secured in the main body portion  20 . 
     As shown in  FIGS. 1 and 2 , a pair of backlash preventing portions  26  bulging inwardly of the main body portion  26  are provided on front end parts of the both side walls  23 . Parts of the both side walls  23  are struck to project inwardly, thereby forming the both backlash preventing portions  26 . When the male tab  90  is inserted into the main body portion  20 , the both backlash preventing portions  26  are arranged proximately to opposite outer ends of the male tab  90  in the width direction, whereby loose movements of the male tab  90  in the width direction are regulated. 
     Further, as shown in  FIGS. 1 and 2 , a pair of stabilizers  27  projecting outwardly of the main body portion  20  are provided on rear end parts of the both side walls  23 . The both stabilizers  27  are formed by cutting parts of the both side walls  23  and bending the cut parts outwardly, and arranged at height positions of the both side walls  23  different from each other. Here, the female terminal fitting  10  is inserted into a cavity (not shown) of a connector housing. In this case, the both stabilizers  27  are fitted into guiding grooves (not shown) communicating with the cavity to guide an insertion movement of the female terminal fitting  10 , whereas it can be known that an insertion posture of the female terminal fitting  10  is not correct if the both stabilizers  27  cannot be fitted into the guiding grooves. Note that the both side walls  23  include no opening parts such as holes except slits formed as the both stabilizers  27  are formed by cutting and bending and the slits are arranged at positions distant from a later-described contact portion  29  of the resilient contact piece  21 . 
     As shown in  FIGS. 2 and 4 , a part of the facing wall  24  is recessed inwardly to form a receiving portion  28 . The inner surface of the receiving portion  28  is arranged along the front-back direction and can come into contact with the upper surface of the male tab  90  inserted into the main body portion  20 . 
     The resilient contact piece  21  is formed by folding a part extending forward from the front end of the base wall  22  in a development state backward (inserting direction of the male tab  90 ) and extends backward substantially at an upward inclination from the front end of the base wall  22  as shown in  FIG. 4 . The resilient contact piece  21  is deflectable and deformable in a vertical direction with a front end part (base end part) connected to the base wall  22  as a supporting point. As shown in  FIG. 1 , the front end part of the resilient contact piece  21  is wider than a part behind it. Further, as shown in  FIGS. 2 and 4 , the embossed contact portion  29  is formed to bulge upwardly in a widthwise central part of a rear end part (free end part) of the resilient contact piece  21 . 
     As shown in  FIG. 4 , a deflectable auxiliary spring piece  30  is provided in the main body portion  20  separately from the resilient contact piece  21 . The auxiliary spring piece  30  is formed on the base wall  22  by cutting and bending while leaving a hole  31 . The auxiliary spring piece  30  extends substantially horizontally after obliquely extending forward (direction opposite to the inserting direction of the male tab  90 ) at an upward inclination from the rear end, and is deflectable and deformable in the vertical direction with a rear end part connected to the base wall  22  as a supporting point. A front end part (free end part) of the auxiliary spring piece  30  is arranged in contact with the rear end part of the resilient contact piece  21  from below and a spring force of the resilient contact piece  21  is assisted by the resilient contact piece  21  being resiliently supported from below by the auxiliary spring piece  30 . Note that, as shown in  FIG. 1 , the auxiliary spring piece  30  is narrower than the resilient contact piece  21  as a whole and the front end part of the auxiliary spring piece  30  can come into contact with a widthwise central part of the rear end part of the resilient contact piece  21 . 
     Further, as shown in  FIGS. 1 and 4 , the base wall  22  is provided with a locking projection  32  before the auxiliary spring piece  30 . The locking projection  32  is formed by cutting a part of the base wall  22  and bending the cut part via the hole  31 , and in the form of a claw projecting downwardly of the base wall  22 . When the female terminal fitting  10  is inserted into the cavity of the connector housing, a locking lance (not shown) projecting at an inner wall of the cavity is arranged to be lockable to the locking projection  32 , whereby the female terminal fitting  10  is retained in the cavity. 
     As shown in  FIGS. 1 and 2 , a pair of excessive deflection regulating pieces  33  are integrally provided to opposite side edges (opposite widthwise ends) of the rear end part of the resilient contact piece  21  at a position overlapping the contact portion  29  in the front-back direction. The both excessive deflection regulating pieces  33  are formed by bending opposite parts of the rear end part of the resilient contact piece  21  protruding laterally outwardly downwardly, i.e. toward a side where the base wall  22  is located. Specifically, the both excessive deflection regulating pieces  33  are in the form of plate pieces and lower end parts (bent tip parts) thereof are formed into such a substantially trapezoidal shape in a side view that a width in the front-back direction is gradually narrowed toward the lower edge as shown in  FIG. 5 . The lower edges of the lower end parts of the both excessive deflection regulating pieces  33  serve as contact edges  34  to be brought into contact with the inner surface of the base wall  22  when the resilient contact piece  21  is going to be excessively deflected and deformed as described later (see  FIG. 5 ). Further, as shown in  FIGS. 2 and 3 , the both excessive deflection regulating pieces  33  extend downward in directions to be separated from each other while being inclined at a slight angle with respect to the vertical direction. 
     Further, as shown in  FIG. 3 , the both excessive deflection regulating pieces  33  are arranged to be proximate to opposite side edges of the front end part of the auxiliary spring piece  30  and face and cover those opposite side edges of the front end part. Since the rear end part of the resilient contact piece  21  is arranged in contact with the upper surface of the front end part of the auxiliary spring piece  30 , the front end part of the auxiliary spring piece  30  is surrounded on three sides by the rear end part of the resilient contact piece  21  and the both excessive deflection regulating pieces  33 . 
     The structure of the female terminal fitting  10  of this embodiment is as described above. Next, functions and effects of the female terminal fitting  10  are described. 
     When the connector housing is connected to a mating connector housing (both are not shown), the male tab  90  mounted in the mating connector housing is inserted into the main body portion  20  of the female terminal fitting  10  accommodated in the cavity of the connector housing. In the process of inserting the male tab  90 , the male tab  90  slides on the contact portion  29  of the resilient contact piece  21  to deflect and deform the resilient contact piece  21  downwardly and the auxiliary spring piece  30  is also deflected and deformed downwardly by being pressed by the resilient contact piece  21 . In this case, if the front end part of the auxiliary spring piece  30  is going to swing in the width direction, one side edge of the front end part of the auxiliary spring piece  20  comes into contact with the corresponding excessive deflection regulating piece  33  facing in a swinging direction, whereby any further swing (loose movement) of the auxiliary spring piece  30  is suppressed. As a result, a state where the auxiliary spring piece  30  is in contact with the resilient contact piece  21  at a proper position is ensured and the auxiliary spring piece  30  is prevented from being inadvertently brought out of contact with the resilient contact piece  21 . Simultaneously, the swing of the resilient contact piece  21  in the width direction is also suppressed, with the result that the resilient contact piece  21  is smoothly deflected. 
     Further, if the male tab  90  is inserted into the main body portion  20  in a state inclined with respect to a proper insertion posture as shown in  FIG. 5 , the resilient contact piece  21  may be deflected and deformed more than a normal deflection amount by being pressed by this male tab  90  in the oblique posture. However, according to this embodiment, the contact edges  34  of the both excessive deflection regulating pieces  33  come into contact with parts of the inner surface of the base wall  22  at opposite widthwise sides of the hole  31  to hinder any further deflection of the resilient contact piece  21  when the resilient contact piece  21  assumes a posture substantially along the front-back direction immediately before being excessively deflected and deformed (see  FIG. 5 ). Thus, the resilient contact piece  21  is prevented from being excessively deflected and deformed and, simultaneously, the auxiliary spring piece  30  is also prevented from being excessively deflected and deformed. On the other hand, if the female terminal fitting  10  is in the proper posture and the connector housing is properly inserted into the mating connector housing, the resilient contact piece  21  is properly held in contact with the male tab  90  to be electrically conductively connected. 
     As described above, according to this embodiment, the excessive deflection of the resilient contact piece  21  can be prevented even without making a hole or the like on the side wall  23  of the main body portion  20  since the excessive deflection regulating pieces  33  are provided on the resilient contact piece  21  itself. Further, since the excessive deflection regulating pieces  33  are formed by bending the rear end part of the resilient contact piece  21  and the lower end parts (bent tip parts) of the excessive deflection regulating pieces  33  can come into contact with the base wall  22 , an excessive deflection amount of the resilient contact piece  21  can be appropriately adjusted by adjusting the excessive deflection regulating pieces  33  in length. 
     Further, since the pair of excessive deflection regulating pieces  33  are arranged at the opposite widthwise sides of the auxiliary spring piece  30 , a deflection movement of the auxiliary spring piece  30  can be guided and, in addition, the auxiliary spring piece  30  is prevented from being brought out of contact with the resilient contact piece  21 . Furthermore, since the pair of excessive deflection regulating pieces  33  are arranged at the opposite widthwise sides of the front end part of the auxiliary spring piece  30 , the swing of the auxiliary spring piece  30  is effectively suppressed on the front end part of the auxiliary spring piece  30  having a large swing amount when the auxiliary spring piece  30  swings in the width direction, wherefore stability in a deflection movement of the auxiliary spring piece  30  is ensured. 
     The present invention is not limited to the above described and illustrated embodiment. For example, the following modes are also included in the technical scope of the present invention. 
     Only one excessive deflection regulating piece may be provided or three or more excessive deflection regulating pieces may be provided. 
     The excessive deflection regulating piece may be formed on the rear end edge of the resilient contact piece by bending. 
     The excessive deflection regulating piece may be provided before the rear end part of the resilient contact piece. 
     Conversely to the embodiment, the resilient contact piece may extend forward from the rear end of the base wall and be deflectable and deformable with the rear end as a supporting point. 
     The excessive deflection regulating piece may be formed by striking a part of the resilient contact piece toward the base wall. 
     LIST OF REFERENCE SIGNS 
     
         
           10  . . . female terminal fitting 
           20  . . . main body portion 
           21  . . . resilient contact piece 
           22  . . . base wall 
           23  . . . side wall 
           29  . . . contact portion 
           30  . . . auxiliary spring piece 
           33  . . . excessive deflection regulating piece 
           90  . . . male tab