Patent Publication Number: US-6210223-B1

Title: Shielded connector, a set of shielded connectors and method for connecting a shielded connector with a shielded cable

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shielded connector, a set of shielded connectors and a method for connecting a shielded connector with a shielded cable. 
     2. Description of the Related Art 
     A known shielded connector is disclosed in Japanese Unexamined Utility Model Publication No. 5-27983, and is illustrated in FIGS. 6-8. This prior art terminal  1  is provided with an inner terminal  2  and an outer terminal  3 . Three crimping portions also are provided, namely, an inner conductor crimping portion  2   a  on the inner terminal  2 , an outer conductor crimping portion  3   b  on the outer terminal  3  and a sheath crimping portion  3   c  also on the outer terminal  3 . 
     A prior art shielded cable  2  is processed for connection to the prior art shielded connector  1 . As part of this processing, an inner conductor  51  of the shielded cable  50  is exposed by stripping a sheath  54 , an outer conductor  52  and an insulating element  53  at an end of the shielded cable  50 . The inner conductor crimping portion  2   a  of the prior art inner terminal  2  will be fastened to this exposed end of inner conductor  51 . An additional portion of the sheath  54  is stripped at this end of the shielded cable  50  to expose the outer conductor  52 . The outer conductor crimping portion  3   b  of the prior art terminal  3  will be fastened to the exposed portion  56  of the outer conductor  52 , and the sheath crimping portion  3   c  of the prior art terminal  3  will be fastened to the sheath  54  at the end of the shielded cable  50  located behind the exposed portion  56 . 
     The three crimping portions are crimped simultaneously after the aforementioned shielded connector  1  is placed in a crimper. Since the inner terminal  2  is crimped after being accommodated in the outer terminal  3 , it is essential for the outer terminal  3  to be formed with openings  3   a  in its top and bottom walls in order for crimping molds of the crimper to reach the inner terminal  2  accommodated in the outer terminal  3 . However, because of the presence of the openings  3   a , a portion of the inner conductor  51  not covered by the outer conductor  52  and the inner terminal  2  are exposed to the outside through the openings  3   a . This exposure reduces shielding. Thus, depending on the situation, it is necessary to apply additional shielding using another member. 
     The present invention was developed in view of the above problem and an object thereof is to provide a shielded connector, a set of shielded connectors and a method for connecting a shielded connector with a shielded cable allowing for an improved shielding characteristic. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is provided a shielded connector that is connectable with a shielded cable. The shielded cable has an insulating element provided between inner and outer conductors. The outer surface of the outer conductor of the shielded cable is covered by a sheath. The shielded connector comprises an inner terminal that is connectable with the inner conductor. The connector also comprises an outer terminal which is adapted to at least partly accommodate the inner terminal with a dielectric element provided therebetween. The outer connector is connectable with the outer conductor of the shielded cable. The inner terminal is or can be fastened to the inner conductor of the shielded cable at a location that is at least partly outside the outer terminal. A covering portion extends from the outer connector and surrounds at least three sides of that portion of the inner terminal to be fastened to the inner conductor. 
     According to a preferred embodiment, the outer terminal is formed to be fastened to the outer conductor of the shielded cable while the inner terminal is connected with the inner conductor. 
     According to a further preferred embodiment, a shielded connector is connectable with a shielded cable. The cable includes an insulating element between inner and outer conductors, and the outer surface of the outer conductor is covered by a sheath. The shielded connector comprises an inner terminal connectable with the inner conductor. An outer terminal is adapted to accommodate the inner terminal with a dielectric element provided therebetween. The outer terminal also is connectable with the outer conductor. The inner terminal is fastened to the inner conductor of the shielded cable outside the outer terminal. The outer terminal is formed to be fastened to the outer conductor of the shielded cable with the inner terminal connected with the inner conductor. A portion of the inner terminal that is to be fastened to the inner conductor is surrounded at least on three sides by wall surfaces. 
     Accordingly, the outer terminal needs not be formed with openings for the insertion of crimping molds and are therefore allowed to have closed surfaces since the inner terminal is fastened outside the outer terminal. Thus, the inner conductor not covered by the outer conductor and a portion of the inner conductor fastened to the inner conductor can be covered at least on three sides by the wall surfaces of the outer terminal. As a result, shielding performance can be improved. 
     Preferably, the outer conductor is at least partly folded back over the sheath thereby forming a folded portion, and the outer terminal is formed with a crimping portion which can be fastened at least partly to the folded portion or both to the folded portion of the outer conductor and to the sheath. Thus the outer terminal can be fastened to the outer conductor and the sheath by one crimping operation. Accordingly, the crimping molds for crimping the outer terminal can be constructed to crimp one crimping portion, and do not need to be constructed in conformity with a plurality of crimping portions along the length of the outer terminal. Therefore, the crimping molds are allowed to have a simple construction and portions of the crimping molds that correspond to the crimping portion can be made shorter. 
     Most preferably, a portion of the inner terminal to be fastened to the inner conductor is surrounded on three sides by the wall surfaces. Thus, the outer terminal leaves only one surface open. A mating connector is constructed similarly. Additionally the two mateable connectors are oriented during mating such that open surfaces of the respective outer terminals face in opposite directions. Accordingly, the radiation characteristic can be balanced by connecting the male and female shielding connectors with the open surfaces thereof faced in opposite directions. The radiation characteristic is influential on the high-frequency signal transmitted. As a result the shielding characteristic can be improved by the balancing of the radiation characteristic. 
     According to the invention, there is further provided a set of shielded connectors. A first shielded connector in the set has a portion of the inner terminal to be fastened to the inner conductor substantially surrounded on three sides by the covering portion. Thus only one surface is left substantially open. A second mating connector in the set is constructed similarly, but is connectable to the first shielded connector such that the substantially open surface of its outer terminal faces in a different direction, and preferably a substantially opposite direction. 
     The invention also is directed to a method for connecting or crimping a shielded connector, with a shielded cable. The shielded cable has an insulating element provided between inner and outer conductors, and the outer surface of the outer conductor is covered by a sheath. The method comprises fastening an inner terminal of the shielded connector to the inner conductor of the shielded cable at least partly outside an outer terminal of the shielded connector. The method then comprises substantially covering with a covering portion of the outer terminal at least three sides of the section of the inner terminal to be fastened to the inner conductor. 
     According to a preferred embodiment of the invention, the method further comprises fastening the outer terminal to the outer conductor of the shielded cable after the inner terminal is connected with the inner conductor in the inner terminal fastening step. 
     Preferably, the method further comprises stripping the sheath to substantially expose the outer conductor, folding the exposed portion of the outer conductor back over the sheath and fastening a crimping portion of the outer terminal to both the sheath and the outer conductor. 
     Most preferably, in the fastening step crimping pieces of the crimping portion are crimped to at least partly wind on or around the outer conductor with the end of a first crimping piece substantially placed or placeable on that of a second crimping piece. 
     These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view showing parts constructing a shielded connector according to one embodiment of the invention. 
     FIG. 2 is a section of an assembled male shielded connector. 
     FIG. 3 is a section of an assembled female shielded connector. 
     FIG. 4 is a side view of the shielded connectors after connection. 
     FIG. 5 is a section of the connected shielded connectors. 
     FIG. 6 is a perspective view of a prior art shielded connector. 
     FIG. 7 is a plan view of the prior art shielded connector. 
     FIG. 8 is a side view partly in section of the prior art shielded connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Shielded connectors  1 O a ,  1 O b  according to this embodiment are connectable with each other and have such an integral construction that inner terminals  20   a ,  20   b  are accommodated in outer terminals  40   a ,  40   b  with dielectric elements  30   a ,  30   b  provided therebetween. Shielded cables  50  are connectable with the shielded connectors  10   a ,  10   b  (see FIG.  1 ). 
     The female shielded connector  10   b  differs from the male shielded connector  10   a  in several respects. First, the inner terminal  20   b  is a female terminal on the female shielded connector  10   b , whereas the inner terminal  20   a  on the male shielded connector  10   a  is a male terminal. Second, the outer terminal  40   b  of the female shielded connector  10   b  is dimensioned to be accommodated in the outer terminal  40   a  of the male shielded connector  10   a . Third, the outer terminal  40   a  of the male shielded connector  10   a  is provided with contact pieces  43 , and a touching or contact piece  48 , whereas the outer terminal  40   b  of the female shielded connector  10   b  has no contact pieces comparable to the elements  43  and  48 . However, since the female and male shielded connectors  10   a ,  10   b  are constructed and assembled similarly in other respects, only the male shielded connector  10   a  is described here to avoid repetitive description and the same or similar construction is identified by the same or similar reference numerals. 
     A side (right side in FIG. 2) of the inner terminal  20   a  of the connector  10   a  to be connected with an unillustrated mating inner terminal is referred to as a front side and an opening direction (an upward direction in FIG. 2) of a covering portion  45  is referred to as an upward direction. 
     The shielded cable  50  has a substantially coaxial construction with an insulating element  53  provided between an inner conductor  51  and an outer conductor  52 . The inner conductor  51  is formed, e.g., by bundling a plurality of strands and the outer conductor  52  is made, e.g., of a braided wire or a metal sheet. The outer surface of the outer conductor  52  is covered by a sheath  54  made, for example, of vinyl. The sheath  54  is stripped at one end of the shielded cable  50  to partly expose the outer conductor  52 . The exposed portion of the outer conductor-then is folded back at least partly over the sheath  54 , to form a folded portion  55 . The insulating element  53  is stripped forwardly of the folded portion  55  to expose part of the inner conductor  51  (see FIG.  1 ). The exposed leading end of the inner conductor  51  is or can be connected with the inner terminal  20   a , and the outer conductor  52  is or can be connected with the outer terminal  40   a  via the folded portion  55 . 
     The inner terminal  20   a  of the male shielded connector  10   a  is an electrically conductive male terminal, as shown in FIG. 1, and a front part of the inner terminal  20   a  is formed into a tab that is connectable with the inner terminal  20   b  of the female shielded connector  10   b . The middle of the inner terminal  20   a  is provided with a pair of biting projections  23  for biting into or engaging the inner wall of an accommodating hole  31  of the dielectric element  30   a  when the inner terminal  20   a  is inserted into the dielectric element  30   a , as described later. An inner crimping portion  24  is provided behind the biting projections  23  and preferably is comprised of at least one pair of crimping pieces for fastening to the inner conductor  51 . 
     The dielectric element  30   a  is made of an insulating material, such as resin, and electrically insulates the inner and outer terminals  20   a ,  40   a  from each other. The accommodating hole  31  is formed inside the dielectric element  30   a  to accommodate and fix the inner terminal  20   a . Further, a locking recess  32  is formed in the outer surface of the top of the dielectric element  30   a  and a contact portion  33  is provided on the outer surface of the bottom of the dielectric element  30   a  to fix the dielectric element  30   a  in the outer terminal  40   a  (see FIGS.  1  and  2 ). 
     The outer terminal  40   a  is formed by bending an electrically conductive plate, and a front part thereof is an accommodating portion  41  that preferably is in the form of a substantially rectangular tube. An elastically deformable locking portion  42  is formed in the top wall of the outer terminal  40   a , and projects inwardly and obliquely backward to lock the aforementioned dielectric element  30   a  in a specified position in the accommodating portion  41 . A contact piece  48  is cut in the bottom wall of the outer terminal  40   a  and is bent inwardly at an angle different from 0° or 180°, and preferably substantially at right angles. Further, contact pieces  43  are formed in the right and left walls of the outer terminal  40   a  to project inwardly and obliquely forwardly for elastically contacting the female shielded connector  10   b.    
     The covering portion  45  is provided behind the accommodating portion  41  and is constructed to be substantially closed on three sides by the left, right and bottom walls. The covering portion  45  improves a shielding characteristic for the inner conductor  51  and the inner crimping portion  24  of the inner terminal  20   a  which are to be accommodated therein. This improvement in the shielding characteristic is described later. Stabilizers  44  are provided at the upper ends of the covering portion  45  and project outwardly along the transverse direction of the outer terminal  40   a  (see FIG.  1 ). The stabilizers  44  are configured to prevent an upside-down insertion of the shielded connector  10   a  into an unillustrated connector housing, to introduce the outer terminal  40   a  in a correct direction and to fix the shielded connector  10   a  stably in the connector housing. The stabilizers  44  also function to lock an unillustrated retainer for securely locking the inserted shielded connector  10   a  in the connector housing. 
     An outer crimping portion  46  is provided behind the covering portion  45  for fastening to the outer conductor  52 , preferably to the folded portion  55  of the shielded cable  50 . At least one pair of strip-shaped crimping pieces  47  extend from the bottom of the outer crimping portion  46 . The crimping pieces  47  are spaced apart wider from each other toward their leading ends, and preferably have such a length that they can surround shielded cables of various diameters. 
     The shielded connector  10   a  is assembled as follows. First, the inner crimping portion  24  of the inner terminal  20   a  is fastened to the partly exposed inner conductor  51  before the inner terminal  20   a  is inserted into the outer terminal  40   a.    
     Next, the dielectric element  30   a  is inserted at least partly into the accommodating portion  41  of the outer terminal  40   a  from front. After sufficient insertion, the touching piece  48  comes substantially into contact with the contact portion  33  and the locking portion  42  slips into or is positioned in the locking recess  32 . Thus the dielectric element  30   a  is locked substantially in the specified position in the accommodating portion  41 . The inner terminal  20   a  that has been connected with the inner conductor  51  is inserted at least partly into the accommodating hole  31  of the dielectric element  30   a . The biting projections  23  of the inner terminal  20   a  bite into or engage the wall of the accommodating hole  31  during this insertion to fix the inner terminal  20   a  stably in the dielectric element  30   a , as shown in FIG.  2 . 
     The folded portion  55  of the cable  50  then is placed on the bottom of the crimping portion  46  of the outer terminal  40   a , and the shielded connector  10   a  is placed in an unillustrated crimper. The folded portion  55  is placed on the bottom of the outer crimping portion  46  of the outer terminal  40   a . The crimping portion  46  of the outer terminal  40   a  is held tightly between unillustrated crimping molds and the crimping pieces  47  are crimped or folded into close contact with the outer surface of at least part of the folded portion  55  of the shielded cable  50 . The crimping preferably is carried out such that the end of one crimping piece  47  is placed on that of the other crimping piece  47 . In this way, the male shielded connector  10   a  is assembled. 
     When the shielded connector  10   a  is assembled as shown in FIG.  2 ,the covering portion  45  covers or surrounds portions of the inner conductor  51  that are not covered by the outer conductor  52  and sections of the inner crimping portion  24  of the inner terminal  20   a  that are fastened to the leading end of the inner conductor  51 . 
     Since the inner conductor  51  behind the folded portion  55  is covered by the outer conductor  52  and since a front part of the inner terminal  20   a  accommodated in the accommodating portion  41  is surrounded by the walls of the accommodating portion  41 , they are both surrounded on their four sides by the conductive elements. Thus, there is no problem in shielding at those locations. It is most desirable in terms of shielding characteristic to similarly cover or enclose, on four sides, those portions the inner conductor  51  that are not covered by the outer conductor  52  and portions of the inner crimping portion  24  that are not covered on four sides by the accommodating portion  41 . 
     However, in this embodiment, only the upper surface of the covering portion  45  is open and the remaining three surfaces are closed since the shielded connectors  10   a ,  10   b  are locked by locking portions when accommodated in the unillustrated connector housing. Only a slight clearance is formed between the covering portion  45  and the outer crimping portion  46  in order to easily form the outer crimping portion  46 . However it is desirable to substantially close this clearance. In this embodiment, the clearance is made as narrow as possible while realizing the above purpose. 
     According to the shielded connectors  10   a ,  10   b  of this embodiment, the portion of the inner conductor  51  not covered by the outer conductor  52  and the portion of the inner terminal  20   a  at and near the inner crimping portion  24  are covered substantially by the left, right and bottom walls of the shielded connector  10   a  or the left, right and top walls, in the case of the shielded connector  10   b  (see FIGS.  2  and  3 ). Thus, the shielding characteristic can be improved remarkably with respect to leftward, rightward and downward (upward in the case of the shielded connector  10   b ) directions. Further, the shielding characteristic can be improved further by making the clearance between the covering portion  45  and the outer crimping portion  46  as narrow as possible. 
     In the shielded connectors  10   a ,  10   b  according to this embodiment, the inner terminals  20   a ,  20   b  and the respective inner conductors  51  are accommodated at least partly in the outer terminals  40   a ,  40   b , which then are fastened to the folded portions  55 . Accordingly, the outer terminals  40   a ,  40   b  can be fastened by applying crimping in only one position. Thus, the crimping molds used to crimp the outer terminals  40   a ,  40   b  can be constructed to crimp only the outer crimping portion  46 , and the crimping molds need not be constructed in conformity with a plurality of crimping portions. Thus, the crimping molds are allowed to have a simple construction and the entire length of the portion of each mold corresponding to the outer crimping portion  46  can be made shorter. Further, since the outer terminals  40   a ,  40   b  are crimped only once, efficiency in crimping operation can be improved since the adjustment of a crimping force and confirmation as to whether or not fastening has been satisfactorily performed are made only for the single crimping portion  46 . 
     FIGS. 4 and 5 show a state where the male and female shielded connectors  10   a ,  10   b  are connected with each other. In FIGS. 4 and 5, the shielded connectors  10   a ,  10   b  are connected with the open surfaces of their covering portions  45  facing in different directions. 
     In the case that the covering portions  45  of the shielded connectors  10   a ,  10   b  have an open surface, the intensity of a high frequency signal may change slightly due to its radiation to the outside via the open surface and/or noise may enter from the outside. In such a case, if the open surfaces of the male and female connectors  10   a ,  10   b  are facing in the same direction, the signal radiates in the same direction and noise enters from the same side. This causes a variation in the high-frequency signal, which then causes a variation in the performance characteristic of the side surfaces of the connector, thereby causing a problem. 
     By connecting the male and female shielded connectors  10   a ,  10   b  with their open surfaces faced in different directions, the radiation of the high-frequency signal and the intrusion of noise can be balanced symmetrically. Therefore, a performance reduction in a specific direction can be prevented when the high-frequency signal transmitting through the inner conductor  51  passes the shielded connectors  10   a ,  10   b , with the result that the shielding characteristic can be improved. 
     The present invention is not limited to the foregoing embodiments. For example, embodiments as described below are also embraced by the technical scope of the present invention as defined in the claims. Besides the following embodiments, a variety of changes can be made without departing from the scope and spirit of the present invention as defined in the claims. 
     Although the covering portion  45  has an open surface in the foregoing embodiment, it may be closed on its four sides by wall surfaces without having any open surface. With such a construction, shielding performance can be further improved. 
     Although the female and male shielded connectors are connected with each other in the foregoing embodiment, the invention is also applicable to a shielded connector directly connectable with a circuit board of an electric equipment or the like. 
     The covering portion  45  may be provided as a separate or as an integral or unitary part of the outer terminal  40 .