Patent Publication Number: US-11381040-B2

Title: Outer conductor terminal and shield connector

Description:
TECHNICAL FIELD 
     The present invention relates to an outer conductor terminal and a shield connector. 
     BACKGROUND 
     Patent Document 1 discloses a shield terminal with an inner conductor terminal, an outer conductor terminal surrounding the outer periphery of the inner conductor terminal and a dielectric interposed between the outer conductor terminal and the inner conductor terminal. Patent Document 1 also discloses a shield connector with the shield terminal and a connector housing for accommodating the shield terminal. The outer conductor terminal is composed of an outer conductor terminal body for covering the inner conductor terminal, and a lid body for covering a back surface side of the outer conductor terminal body. The outer conductor terminal body includes base plate assembly tabs projecting downward on four corners. The lid body is fit to a rear part of the outer conductor terminal body from outside. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: JP 2008-192474A 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved 
     In the above case, a special lock structure is not provided between the lid body and the outer conductor terminal body. However, a lock structure is preferably provided to ensure further reliability in retaining the shape of the outer conductor terminal. Such a structure that the lid body is formed with a U-shaped slit, an inner part of the slit is bent inward to form a projection and the outer conductor terminal body is formed with a locking edge to be locked to the projection with the outer conductor terminal body covered with the lid body is, for example, considered as a lock structure of this type. 
     However, a return current in response to an electrical signal transmitted by the inner conductor terminal is generated in the outer conductor terminal and flows to a ground pattern of a circuit board via the base plate assembly tabs. Thus, a path of the return current may be blocked by the U-shaped slit formed in the lid body. If the return current flows to an outer surface side (surface side) of the outer conductor terminal through the U-shaped slit, a problem occurs in which the return current becomes a new noise source. 
     The present invention was completed on the basis of the above situation and aims to provide an outer conductor terminal capable of ensuring a good shielding property and a shield connector using the outer conductor terminal. 
     Means to Solve the Problem 
     The present invention is directed to an outer conductor terminal with a terminal body capable of surrounding an outer periphery of an inner conductor terminal, a back plate portion for closing a back surface opening of the terminal body in a closed state by being displaced from an open state to the closed state with respect to the terminal body, and a side plate portion connected to the back plate portion, the side plate portion constituting a part of a side surface part of the terminal body in the closed state, wherein the back plate portion includes a board connecting piece projecting toward a circuit board and to be electrically connected to the circuit board, and the side plate portion includes a linear slit extending toward the circuit board and a locking portion bent via the slit, the locking portion holding the back plate portion in the closed state by locking the body portion. 
     Effect of the Invention 
     Since both the board connecting piece of the back plate portion and the slit of the side plate portion are formed to extend toward the circuit board, it can be prevented that a path of a return current flowing to a ground pattern of the circuit board through the board connecting piece is blocked by the slit, and the leakage of the return current to an outer surface side of the outer conductor terminal through the slit can be hindered. As a result, noise can be reliably emitted to the ground pattern and good shielding performance can be exhibited. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a back view of a shield connector according to one embodiment of the present invention. 
         FIG. 2  is a section along A-A of  FIG. 1 . 
         FIG. 3  is a side view of an outer conductor terminal in an open state. 
         FIG. 4  is a front view of the outer conductor terminal in the open state. 
         FIG. 5  is a section along B-B of  FIG. 4 . 
         FIG. 6  is a bottom view of the outer conductor terminal in the open state. 
         FIG. 7  is a partial enlarged side view of the outer conductor terminal in a closed state. 
     
    
    
     DETAILED DESCRIPTION TO EXECUTE THE INVENTION 
     Preferred embodiments of the present invention are described below. 
     (1) The board connecting piece is capable of contacting along a surface of the circuit board. If the board connecting piece is for surface mounting in this way, assemblability with the circuit board can be improved. Further, since the board connecting piece is provided on the back plate portion, a part capable of contacting along the surface of the circuit board can be easily formed by bending. 
     (2) A shield connector using the outer conductor terminal having the above configuration is provided with a shield terminal including the outer conductor terminal, the inner conductor terminal and a dielectric interposed between the outer conductor terminal and the inner conductor terminal, and a connector housing for accommodating the shield terminal. According to the above configuration, a good shielding property can be realized, wherefore this shield connector is suitably used, for example, as a shield connector for high speed communication of an automotive vehicle. 
     Embodiment 
     Hereinafter, one embodiment is described with reference to the drawings. A shield connector  10  mounted in an unillustrated vehicle such as an electric or hybrid vehicle and used for high speed communication between in-vehicle electrical components is shown in this embodiment. This shield connector  10  is mounted on a surface of a circuit board  90  as shown in  FIG. 2 . Note that, in the following description, a right side of  FIG. 2  is referred to as a front side concerning a front-rear direction, and upper and lower sides are based on a vertical direction of  FIG. 2 . 
     As shown in  FIG. 2 , the shield connector  10  includes a shield terminal  20  and a connector housing  60  for accommodating the shield terminal  20 . The shield terminal  20  includes an inner conductor terminal  21 , an outer conductor terminal  22  surrounding the outer periphery of the inner conductor terminal  21  and a dielectric  23  interposed between the outer conductor terminal  22  and the inner conductor terminal  21 . 
     The inner conductor terminal  21  is formed, such as by bending a conductive metal plate. The inner conductor terminal  21  includes a tab  24  projecting forward. The tab  24  is electrically connected to an unillustrated mating terminal fitting provided in a mating connector when the shield connector  10  is connected to the unillustrated mating connector. The inner conductor terminal  21  includes one connecting piece  25  bent downward at an intermediate position in a length direction and further extending rearward from a lower end part. The connecting piece  25  is in contact with and electrically connected to a conductive pattern (conductive path) for signal transmission formed on the surface of the circuit board  90 . 
     The dielectric  23  is made of an insulating synthetic resin material having a predetermined relative permittivity and includes a terminal accommodation chamber  26  penetrating in the front-rear direction inside. The inner conductor terminal  21  is accommodated in the terminal accommodation chamber  26 . The inner conductor terminal  21  is held in the dielectric  23  with the tab  24  projecting forward from a front end opening of the terminal accommodation chamber  26 . The inner conductor terminal  21  and the outer conductor terminal  22  are kept insulated from each other by the dielectric  23 . 
     The outer conductor terminal  22  is formed, such as by bending a conductive metal plate. The outer conductor terminal  22  is composed of a tubular portion  27  penetrating in the front-rear direction and a back unit  28  arranged behind the tubular portion  27 . A specific structure of the outer conductor terminal  22  is described in detail later. 
     The connector housing  60  is made of synthetic resin and includes, as shown in  FIG. 2 , a base wall portion  61  substantially in the form of a rectangular plate substantially extending along the vertical direction and a receptacle  62  substantially in the form of a rectangular tube projecting forward from the outer peripheral edge of the base wall portion  61 . As shown in  FIG. 1 , the connector housing  60  includes a pair of side wall portions  63  projecting rearward from both left and right ends of the base wall portion  61 . 
     As shown in  FIG. 2 , the receptacle  62  includes a housing lock portion  64  on the inner surface of an upper wall. An unillustrated mating connector is fit into the receptacle  62 . The housing lock portion  64  functions to lock the mating connector in the receptacle  62  and hold the both connectors in a connected state. 
     The base wall portion  61  includes a mounting hole  65  having a substantially circular cross-section and penetrating in the front-rear direction (wall thickness direction) at a position slightly below a vertical center in a lateral center. The tubular portion  27  of the outer conductor terminal  22  is inserted into the mounting hole  65  of the base wall portion  61 . The outer conductor terminal  22  is mounted into the connector housing  60  with a front part of the tubular portion  27  projecting into the receptacle  62  and the back unit  28  exposed behind the base wall portion  61  (see  FIG. 1 ). A part of the outer conductor terminal  22  exposed behind the base wall portion  61  has both left and right sides covered and protected by the side wall portions  63 . 
     The tubular portion  27  of the outer conductor terminal  22  has a circular tube shape (tube shape having a circular cross-section) and includes, as shown in  FIGS. 4 and 6 , butting ends  29  in a lateral center of a lower end. The butting ends  29  of the tubular portion  27  are provided with projections and recesses  31  arranged in the front-rear direction. The tubular portion  27  is maintained in the circular tube shape by the engagement of the projections and recesses  31 . 
     As shown in  FIGS. 3 and 5 , the tubular portion  27  includes a pair of body-side slits  31  (only one is shown) linearly (along one straight line) open along the vertical direction in vertical centers of both left and right sides, and a pair of outer locking portions  33  for the connector housing  60  on front sides and a pair of inner locking portions  34  for the dielectric  23  on rear sides, out of both front and rear sides across the both body-side slits  32 . The both outer locking portions  33  are formed by bending side wall parts of the tubular portion  27  outward via the body-side slits  32  and in the form of claws substantially triangular in a side view. The both outer locking portions  33  lock the base wall portion  61 , whereby the outer conductor terminal  22  penetrating through the mounting hole  65  is held and fixed in the connector housing  60 . The both inner locking portions  34  are formed by bending side wall parts of the tubular portion  27  inward via the body-side slits  32  (see  FIG. 4 ) and in the form of claws substantially triangular in a side view. The inner locking portions  34  are shaped to be one size smaller than the outer locking portions  33 . The both inner locking portions  34  lock the dielectric  23 , whereby the dielectric  23  is held and fixed in the tubular portion  27 . 
     As shown in  FIGS. 3, 5 and 6 , the back unit  28  includes a coupling portion  39  having a semicircular cross-section and projecting rearward while being connected to an upper half of the tubular portion  27  without any step, lock receiving portions  41  connected to the lower end of the coupling portion  39 , a fulcrum portion  42  connected to a lateral center (also an upper end) of the rear end of the coupling portion  39 , a back plate portion  43  connected to the fulcrum portion  42  on a side opposite to the coupling portion  39  and a pair of side plate portions  44  connected to both left and right ends of the back plate portion  43 . A terminal body  45  is constituted by a part of the outer conductor terminal  22  composed of the tubular portion  27 , the coupling portion  39  and the lock receiving portions  41  (excluding the fulcrum portion  42 , the back plate portion  43  and the side plate portions  44 ). 
     A space below the coupling portion  39  and the lock receiving portions  41  and behind the tubular portion  27  serves as a space portion  36  which is open downward and rearward when the back plate portion  43  is in an open state and is open downward when the back plate portion  43  is in a closed state. 
     As shown in  FIGS. 4 and 6 , a pair of the lock receiving portions  41  are shaped to project on both circumferential ends, i.e. lower ends, of the coupling portion  39 . Each of the both lock receiving portions  41  is in the form of a plate rectangular in a side view and connected to a rear part of the lower end of the coupling portion  39  and hangs down from the coupling portion  39 . The back unit  28  (also the terminal body  45 ) is formed with substantially right-angled steps  46  facing the space portion  36  from the lower ends of the coupling portion  39  to the front ends of the lock receiving portions  41 . The both lock receiving portions  41  include lock receiving edges  47  extending along the vertical direction on front ends. 
     As shown in  FIG. 6 , the fulcrum portion  42  is a narrow flexible hinge located between the coupling portion  39  and the back plate portion  43  and linking the both. 
     The back plate portion  43  is rotationally displaceable via the fulcrum portion  42  with respect to the coupling portion  39  to the open state (see  FIGS. 3 to 6 ) in which the fulcrum portion  42  extends straight and is arranged substantially horizontally and to the closed state (see  FIGS. 1, 2 and 7 ) in which the fulcrum portion  42  is turned and bent and arranged substantially perpendicularly. As shown in  FIG. 1 , the back plate portion  43  includes a back plate body  48  rectangular in a back view and capable of covering a rear surface opening of the terminal body  45  in the closed state and a pair of strip-like board connecting pieces  49  projecting from both left and right ends of the lower edge (end edge on a lower side in the closed state) of the back plate body  48 . 
     As shown in  FIGS. 2 and 7 , each of the both board connecting pieces  49  is bent into a substantially L shape in a side view, thereby including a connecting base end part  51  hanging down from the back plate body  48  toward the circuit board  90  along the vertical direction in the closed state and a connecting tip part  52  (surface contact portion) bent at the lower end of the connecting base end part  51  to extend rearward. The connecting tip parts  52  are electrically connected to a ground pattern formed on the surface of the circuit board  90 . 
     As shown in  FIG. 7 , the both side plate portions  44  are in the form of plates substantially rectangular in a side view and connected substantially at a right angle to both left and right ends of the back plate portion  43 , and project forward from the both left and right ends of the back plate portion  43  in the closed state. When the back plate portion  43  is in the closed state, the upper ends of the both side plate portions  44  are arranged along the lower ends of the coupling portion  39  and respectively cover the corresponding lock receiving portions  41  from outside. 
     As shown in  FIG. 7 , each of the both side plate portions  44  includes a slit  53  linearly (along a straight line) open along the vertical direction in the closed state substantially in a central part and a locking portion  54  for the lock receiving portion  41  on a front side, out of both front and rear sides across the slit  53 . Each of the both locking portions  54  is bent inward via the slit  53  and formed into a flat trapezoidal shape bulging from a substantially U-shaped peripheral edge part  55  having a front edge and upper and lower edges located in front of the slit  53  (see  FIGS. 5 and 6 ). The both locking portions  54  include locking edges  56  extending along the vertical direction on rear ends, which are also front edges of cuts of the slits  53 . 
     Next, functions and effects of this embodiment are described. 
     When the back plate portion  43  is in the open state, the dielectric  23  carrying the inner conductor terminal  21  is inserted into the outer conductor terminal  22 . Subsequently, the back plate portion  43  is rotationally displaced from the open state to the closed state via the fulcrum portion  42 . In the process of displacing the back plate portion  43  to the closed state, the locking portions  54  of the both side plate portions  44  interfere with the corresponding lock receiving portions  41  and the both side plate portions  44  are expanded and deformed (resiliently deformed) with parts coupled to the back plate portion  43  as fulcrums. 
     When the back plate portion  43  reaches the closed state, a back surface opening of the terminal body  45  is closed by the back plate portion  43  and the both resiliently returned side plate portions  44  cover the entire corresponding lock receiving portions  41  from outside to constitute parts of side surface parts of the terminal body  45 . Further, the locking portions  54  of the both side plate portions  44  lock the corresponding lock receiving portions  41  and the locking edges  56  of the locking portions  54  come into contact with the lock receiving edges  47  of the lock receiving portions  41  (see  FIG. 7 ). In this way, a return displacement of the back plate portion  43  to the open state is prevented and, eventually, the outer conductor terminal  22  is maintained in a box shape. 
     When the back plate portion  43  is in the closed state, front end lower parts of the lock receiving portions  41  are facing upper parts of the slits  53  of the side plate portions  44  and the front ends of the side plate portions  44  are vertically arranged along the rear end of the tubular portion  27  in a side view. 
     Subsequently, the outer conductor terminal  22  is inserted into the mounting hole  65  of the base wall portion  61  of the shield connector  10  to be assembled. Thereafter, the shield connector  10  is disposed on the surface of the circuit board  90 . In this way, the connecting piece  25  is conductively connected to a conductive pattern formed on the surface of the circuit board  90  and the connecting tip parts  52  of the both board connecting pieces  49  are conductively connected to the ground pattern formed on the surface of the circuit board  90 . Here, the both board connecting pieces  49  are arranged at both left and right sides of the connecting piece  25  (see  FIG. 1 ). 
     If an electrical signal flows in the inner conductor terminal  21 , a return current in response to the electrical signal is generated in the outer conductor terminal  22 . The return current flows from the coupling portion  39  to the circuit board  90  through the back plate portion  43  along the inner surface of the outer conductor terminal  22 , and is dropped to the ground pattern of the circuit board  90  via the both board connecting pieces  49 . 
     In this case, the slits  53  formed as the locking portions  54  are bent linearly extend along the vertical direction, which is a flowing direction of the return current toward the circuit board  90 , similarly to the connecting base end parts  51  of the both board connecting pieces  49 . Thus, the slits  53  do not substantially impede the flow of the return current. Further, if the slits  53  are shaped to linearly extend in the vertical direction, the leakage of the return current to the outer surface side of the outer conductor terminal  22  can be reduced and noise emitted to the outside of the shield connector  10  can also be reduced. 
     As described above, since the both board connecting pieces  49  of the back plate portion  43  and the slits  53  of the both side plate portions  44  are all formed to extend toward the circuit board  90  according to this embodiment, it can be prevented that a path of the return current is blocked by the slits  53  when the return current flows to the ground pattern of the circuit board  90  through the both board connecting pieces  49  and the leakage of the return current to the outer surface side of the outer conductor terminal  22  through the slits  53  can be hindered. As a result, noise can be reliably discharged to ground and good shielding performance can be exhibited. 
     Further, since the board connecting pieces  49  are for surface mounting by including the connecting tip parts  52  capable of contacting along the surface of the circuit board  90 , assemblability with the circuit board  90  can be improved. Further, since the board connecting pieces  49  are provided on the back plate portion  43 , the connecting tip parts  52  of the board connecting pieces  49  can be easily formed by bending. 
     Other Embodiments 
     Other embodiments are briefly described below. 
     (1) The tubular portion of the outer conductor terminal may be in the form of a rectangular tube. Further, the tubular portion may be shaped to be open on the circuit board side. 
     (2) The number of the board connecting pieces is arbitrary. One, three or more board connecting pieces may be provided. 
     (3) The back plate portion may be constituted by a separate member removable from the terminal body. 
     (4) The board connecting pieces may be of a through hole type that are formed along the vertical direction as a whole and inserted into through holes of the circuit board to be connected. 
     LIST OF REFERENCE NUMERALS 
     
         
         
           
               10  . . . shield connector 
               20  . . . shield terminal 
               21  . . . inner conductor terminal 
               22  . . . outer conductor terminal 
               23  . . . dielectric 
               27  . . . tubular portion 
               43  . . . back plate portion 
               44  . . . side plate portion 
               45  . . . terminal body 
               49  . . . board connecting piece 
               54  . . . locking portion 
               60  . . . connector housing 
               90  . . . circuit board