A shielding terminal and a mounting method therefore

Abstract: [Object] To further strengthen a fastening force of a shielding terminal to a shielded cable. [Solution] An inner metal locking portion 30 is formed in the upper surface of a rear end part of a connecting portion 15 of an inner terminal 11 by making a cut in this upper surface and bending a cut portion outward to project obliquely backward, and a second locking hole 32 is so formed in the upper wall of a rear end portion of a dielectric element 13 as to penetrate the upper wall. Inner surfaces of an accommodating hole 25 of the dielectric element 13 are formed with ribs 34 to 37 for partly filling a clearance between these inner surfaces and the connecting portion 15 of the inner terminal 11. When the inner terminal 11 is pushed to a proper position in the accommodating hole 25 of the dielectric element 13 fixed in the outer terminal 12, the inner metal locking portion 30 having restored to its original shape fits into the second locking hole 32, with the result that the inner terminal 11 is locked in the dielectric element 13 so as not to come out. Simultaneously, the inner terminal 11 is so accommodated as not to shake with the left and right side surfaces of the connecting portion 15 pressed by first and second ribs on the left and right sides and with the upper and bottom surfaces thereof pressed by third and fourth ribs 36, 37.

Description: The present invention relates to a shielding terminal to be connected with an end of a shielded cable and a mounting method therefor. A shielding terminal shown in FIGS. 8 and 9 is known as a shielding terminal of this type. This terminal is provided with an inner terminal "a" to be connected with a mating terminal and an outer terminal "c" accommodating the inner terminal "a" with a dielectric element "b" provided therebetween. The inner terminal "a" is crimped into connection with an end of a core "e" of a shielded cable "d", and the outer terminal "c" is crimped into connection with ends of a braided wire "f" and a sheath "g". Such a construction is disclosed in Japanese Unexamined Utility Model Publication No. 5-27983 and other publications. It is one of essential points for the shielding terminal of this type to have a large fastening force to the shielded cable "d" in order to prevent the shielded cable "d" from being detached from the shielded terminal when a pulling force acts on the shielded cable "d". Conventionally, biting blades have been formed to project from the outer surface of the inner terminal "a" to prevent such a detachment by causing the biting blades to bite in the inner surface of the dielectric element "b". Another shielding terminal of this type is known from EP 1 003 250. A section of an inner conductor of a shielded cable that is not covered by an outer conductor and a portion of an inner terminal at and near an inner crimping portion that is fastened to the leading end of the inner conductor are covered on three sides by a covering portion. By connecting the male and female shielded connectors with opening surfaces of the covering portions thereof faced in opposite directions, radiation characteristic can be balanced. Therefore, an influence on a high-frequency signal transmitting through the inner conductor can be reduced when it is passing through the shielded connectors, with the result that shielding characteristic can be improved. GB-A-1 100 786 discloses a coaxial socket with a substantial cylindrical outer conductive shell stamped and formed from a metal sheet, a substantially cylindrical insulating insert having an inner bore supporting an inner contact member coaxially within the outer shell, the outer shell being formed from a blank to a cylindrical shape having a longitudinally extending open seam and an inner annular recess formed by an outward annular deformed part at its rear end, and the insulating insert having an outer annular projection at its rear end corresponding to the inner annular recess of the shell. However, in the conventional shielding terminal, a groove is formed behind the biting blades biting in the inner surface, and no sufficient force to prevent the detachment can be obtained due to an insufficient degree of engagement. Thus, there is a demand for a further improvement. The present invention was developed in view of the above situation and an object thereof is to prevent the inner terminal from shaking in the dielectric element. This object is solved according to the invention by a shielding terminal according to claim 1 and by a method for mounting a shielding terminal according to claim 6. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a shielding terminal to be connected with an end of a shielded cable, comprising: an inner terminal to be connected with a core of the shielded cable, an outer terminal to be connected with a shield layer of the shielded cable while at least partly accommodating the inner terminal with a dielectric element provided between the inner and outer terminals, at least one metal locking portion formed in an outer surface of the inner terminal, and at least one locking hole engageable with the metal locking portion and formed in an inner surface of the dielectric element where the inner surface of the dielectric element is formed with at least one projection projecting from the inner surface of the dielectric element for at least partly filling a clearance between the inner surface of the dielectric element and the inner terminal by coming into contact with the outer surface of the inner terminal. The detachment of the inner terminal connected with the core from the dielectric element is effectively prevented by fitting the metal locking portion into the locking hole for engagement, with the result that a fastening force of the shielding terminal to the shielded cable can be strengthened. According to a preferred embodiment of the invention, the at least one metal locking portion is formed in the inner terminal by making at least one cut in the outer surface thereof and bending a cut portion. Preferably, the metal locking portion is made to slantingly project backwards when seen in a direction of insertion of the inner terminal into the dielectric element. Preferably, the inner surface of the dielectric element is formed with at least one filling or bridging portion for partly filling or bridging a clearance between the inner surface of the dielectric element and the inner terminal by coming into contact with the outer surface of the inner terminal. With the locking construction realized by fitting the metal locking portion into the locking hole, the inner terminal is likely to shake in the dielectric element. However, in the present invention, the inner terminal is prevented from shaking since the clearance is filled or bridged by the filling or bridging portion to preventing such a shake. This in turn prevents a contact portion of the inner terminal with a mating terminal from making fine sliding movements or being partially abraded. Further preferably, the inner terminal is formed with at least one resilient or elastic contact piece to be brought into contact with a mating terminal and the filling or bridging portion fills the clearance in a direction substantially parallel to an elastically deforming direction of the resilient or elastic contact piece, i.e. the filling or bridging portion(s) are preferably provided on the inner surfaces of the dielectric element facing the resilient or elastic contact piece(s). If the inner terminal is a male terminal provided with an elastic contact piece, the elastic contact piece may undergo an excessive elastic deformation by being pushed by a tab of a mating male terminal in the case that it is shaken in a direction parallel to its elastically deforming direction. However, in the present invention, since the clearance is filled or bridged in the direction parallel to the elastically deforming direction of the elastic contact piece, the inner terminal is prevented from shaking in the same direction, which in turn prevents the elastic contact piece from undergoing an excessive elastic deformation. Still further preferably, the at least one filling portion comprises at least one projection projecting from the inner surface of the dielectric element. Most preferably, the outer terminal is provided with an outer metal locking portion engageable with an auxiliary locking hole provided on an outer surface of the dielectric element so as to lock the dielectric element at least partly inserted in the outer terminal. According to the invention, there is further provided a method for mounting or connecting or assembling a shielding terminal, in particular according to the invention or an embodiment thereof, with an end of a shielded cable, comprising the following steps: connecting an inner terminal with a core of the shielded cable, connecting an outer terminal with a shield layer of the shielded cable while at least partly accommodating the inner terminal with a dielectric element provided between the inner and outer terminals, wherein the inner terminal is locked with the dielectric element by engaging at least one metal locking portion formed in an outer surface of the inner terminal with at least one locking hole formed in an inner surface of the dielectric element at least partly filling a clearance between the inner surface of the dielectric element (13) and the inner terminal (11) by providing at least one projection (34; 35; 36; 37) projecting from the inner surface of the dielectric element (13) for coming into contact with the outer surface of the inner terminal (11 ). According to a preferred embodiment of the invention, the at least one metal locking portion is formed in the inner terminal by making at least one cut in the outer surface thereof and bending a cut portion. These and other objects, features and advantages of the present invention will become apparent upon reading of the following detailed description of preferred embodirnents and accompanying drawings in which: FIG. 1 is an exploded perspective view of one embodiment of the present invention, FIG. 2 is an exploded side view partly in section of this embodiment, FIG. 3 is a vertical section showing a state where a dielectric element is mounted in an outer terminal, FIG. 4 is a section along X-X of FIG. 3, FIG. 5 is a section along Y-Y of FIG. 3, FIG. 6 is a vertical section showing an assembled state of a shielding terminal and a shielded cable, and FIGS. 7 and 8 are a perspective view and a plan view of a prior art shielding terminal connected with a shielded cable. Hereinafter, one embodiment of the present invention is described with reference to FIGS. 1 to 6. In this embodiment is shown a female shielding terminal 10, which is used by being crimped or folded or bent into connection with an end of a shielded cable 1. The shielded cable 1 has a known structure, i.e. a core 2 preferably formed by bundling a plurality of strands, an insulating layer 3, a shield layer, preferably a braided wire 4 and a sheath 5 e.g. made of a rubber or the like are concentrically arranged in this order from the innermost side as shown in FIGS. 1 and 2. In this embodiment, an end of the shielded cable is processed by stripping an end of the sheath 5 off, at least partly folding the thus exposed section of the braided wire 4 substantially back on the sheath 5, and cutting an exposed end of the insulating layer 3 off to at least partly expose the core 2. The shielding terminal 10 is comprised of an inner terminal 11, an outer terminal 12 and a dielectric element 13 as shown in FIGS. 1 and 2. The inner terminal 11 is formed into a female terminal e.g. by bending a metallic plate, a connecting portion 15 preferably in the form of a substantially rectangular tube is formed at its leading end side, and a pair of transversely arranged inner crimping pieces 16 to be crimped or folded or bent into connection with the core 2 of the shielded cable 1 are formed behind or adjacent to the connecting portion 15. A preferably pair of left and right resilient or elastic contact pieces 17 to be connected with a tab (not shown) of a mating male inner terminal are formed at the left and right side surfaces of the connecting portion 15. The preferably two elastic contact pieces 17 cantilever forward and are bent so that the facing surfaces thereof at the leading end bulge out inwardly. They are resiliently or elastically deformable in such directions that their leading ends move toward and away from each other, and the tab of the mating terminal is insertable therebetween. The outer terminal 12 is likewise formed e.g. by bending a metallic plate and is provided at its front side with an accommodating portion 20 substantially in the form of a large rectangular tube and at its rear side with a pair of transversely arranged outer crimping pieces 21 to be crimped or bent or folded into connection with a folded section of the braided wire 4 of the shielded cable 1. Wedge-shaped projections 22 are formed at the base ends of the outer crimping pieces 21 and on the outer crimping piece 21 to be located more inside in its wound state. Further, a portion of the bottom wall at the rear end of the accommodating portion 20 is cut off, and stabilizers 23 project laterally outward from the bottom edges of the left and right side walls of the rear end of the accommodating portion 20. The dielectric element 13 is made of an insulating material such as a synthetic resin, and acts to electrically insulate the inner and outer terminals 11, 12 from each other. The dielectric element 13 has a shape substantially mating or conforming that of the inner and outer terminals 11, 12 and preferably is in the form of a substantially rectangular tube having a thick wall and is at least partly fittable into the front end of the accommodating portion 20 of the outer terminal 12, and an accommodating hole 25 into which the connecting portion 15 of the inner terminal 11 is to be at least partly accommodated is defined inside the dielectric element 13. A flange 24 to be brought into abutment against the front edge of the accommodating portion 20 of the outer terminal 12 is formed at the front surface of the dielectric element 13, and a terminal insertion opening 26 into which the tab of the mating terminal is to be inserted is defined at the front end of the accommodating hole 25. Further, a lower half of the rear end of the dielectric element 13 is cut off so as to substantially conform to the configuration of the accommodating portion 20 of the outer terminal 12. A outer metal locking portion 27 is formed in the upper or lateral surface of the leading end of the accommodating portion 20 of the outer terminal 12 preferably by making a cut or a plurality of cuts in this upper surface and bending a cut portion inward in such a manner as to extend obliquely backward, whereas a first locking hole or recess 28 into which the outer metal locking portion 27 of the outer terminal 12 is at least partly fittable is formed in the upper surface of the leading end of the dielectric element 13. The outer metal locking portion may be also made by embossing a corresponding portion of the accommodating portion 20 of the outer terminal 12 (not shown). An inner metal locking portion 30 is formed in the upper surface of the rear end of the connecting portion 15 of the inner terminal 11 preferably by making a cut or a plurality of cuts in this upper surface and bending a cut portion outward to project obliquely backward. On the other hand, a second locking hole or recess 32 in which the inner locking portion 30 of the inner terminal 11 is at least partly fittable is formed to preferably penetrate the upper wall of the rear end of the dielectric element 13. The inner metal locking portion may be also made by embossing a corresponding portion of the inner terminal 11 (not shown). As shown in detail in FIGS. 3 to 5, the inner surfaces of the accommodating hole 25 of the dielectric element 13 are formed with ribs or projections 34 to 37 for partly filling or bridging a clearance between these inner surfaces and the connecting portion 15 of the inner terminal 11. A short first rib 34 and a relatively long second rib 35 are formed substantially in the middle with respect to height direction at the front and rear ends of each of the left and right side surfaces. The ribs 34, 35 can be brought into contact with front and rear areas of the left and right side surfaces of the connecting portion 15 where the elastic contact pieces 17 are formed when the inner terminal 11 is inserted to a proper position in the dielectric element 13. The rear ends of the ribs 34, 35 are formed into slanted guide surfaces 34A, 35A, respectively. A pair of third ribs 36 extend on the ceiling surface of the accommodating hole 25 at the opposite sides of the second locking hole 32 substantially along the entire length of the ceiling surface. A pair of left and right fourth ribs 37 are formed at the front end of the bottom surface of the accommodating hole 25. When the inner terminal 11 is inserted substantially to the proper position in the dielectric element 13, the third ribs 36 and the fourth ribs 37 can be brought into contact with the left and right sides of the upper surface of the connecting portion 15 of the inner terminal 11 substantially along the entire length and with the left and right sides of the front end of the bottom surface of the connecting portion 15, respectively. The rear ends of the third and fourth ribs 36, 37 are also formed into slanted guide surfaces 36A, 37A. Next, the function of this embodiment is described. The shielding terminal 10 is connected with the end of the shielded cable 1 in a following procedure. The end of the shielded cable 1 is processed as described above. First, the inner crimping pieces 16 of the inner terminal 11 are crimped or folded or bent into connection with the end of the core 2. Then, the dielectric element 13 is at least partly inserted into the accommodating portion 20 of the outer terminal 12 preferably from front. The dielectric element 13 is pushed in while resiliently or elastically deforming the outer metal locking portion 27, which is resiliently or elastically restored preferably to its substantially original shape to fit into the first locking hole 28 when the flange 24 comes into contact with the front edge of the accommodating portion 20 as shown in FIG. 3, with the result that the dielectric element 13 is fixed at the front end of the accommodating portion 20. Subsequently, the inner terminal 11 is at least partly inserted into the accommodating portion 20 of the outer terminal 12 preferably from behind and pushed into the accommodating hole 25 of the dielectric element 13 fixed in the accommodating portion 20 while being caught by a jig inserted through an opening 20A formed in the bottom wall of the rear end of the accommodating portion 20. The inner terminal 11 is pushed in while resiliently or elastically deforming the inner metal locking portion 30, which is resiliently or elastically restored preferably substantially to its original shape to fit into the second locking hole 32 of the dielectric element 13 when its front end comes into contact with the front end wall of the accommodating hole 25 as shown in FIG. 6, with the result that the inner terminal 11 is locked in the dielectric element 13 so as not to come out. Simultaneously, the inner terminal 11 is so accommodated as not to shake with the left and right side surfaces of the connecting portion 15 pressed by the first and second ribs 34, 35 and with the upper and bottom surfaces thereof pressed by the third and fourth ribs 36, 37. Finally, the outer crimping pieces 21 of the outer terminal 12 are crimped and at least partly wound or bent or folded around or on the substantially folded section of the braided wire 4, thereby being fastened to the folded section of the braided wire 4 and the end of the sheath 5. At this time, the outer crimping pieces 21 are more strongly fastened by the projections 25 biting in the braided wire 4. As described above, according to this embodiment, the inner terminal 11 is locked in the dielectric element 13 so as not to come out by fitting the inner metal locking portion 30 of the inner terminal 11 into the second locking hole 32 of the dielectric element 13. This effectively prevents the inner terminal 11 from coming out of the dielectric element 13 when a pulling force acts on the core 2 of the shielded cable 1. With the locking construction realized by fitting the metal locking portion 30 into the locking hole 32, the tab of the mating male terminal inserted between the elastic contact pieces 17 may be pushed to cause the elastic contact pieces 17 to undergo an excessive elastic deformation if the inner terminal 11 should shake in the dielectric element 13, particularly if it shakes in transverse direction parallel to the elastically deforming direction of the elastic contact pieces 17. In this embodiment, shake in transverse direction is prevented by the left and right ribs 34, 35, thereby preventing the inner terminal 11 from shaking in the same direction. This prevents the elastic contact pieces 17 from undergoing an excessive elastic deformation. Since shake of the inner terminal 11 in vertical direction is also prevented, it prevents a contact portion thereof with the tab of the mating male terminal from making fine sliding movements or being partially abraded. The present invention is not limited to the above described and illustrated embodiments. For example, a following embodiment is also embraced by the technical scope of the present invention as defined in the claims. Beside the following embodiment, various changes can be made without departing from the scope and spirit of the present invention as defined in the claims. (1) Although the female shielding terminal is illustrated in the foregoing embodiment, the present invention is similarly applicable to male shielding terminals. LIST OF REFERENCE NUMERALS 1 ... shielded cable 2 ... core 3 ... insulating layer 4 ... braided wire (shield layer) 5 ... sheath 10 ... shielding terminal 11 ... inner terminal 12 ... outer terminal 13 ... dielectric element 15 ... connecting portion 17 ... elastic contact piece 25 ... accommodating hole 30 inner metal locking portion (metal locking portion) 32 ... second locking hole (locking hole) 34 to 37... rib (filling portion)

Claims: A shielding terminal (10) to be connected with an end of a shielded cable (1), comprising: an inner terminal (11) to be connected with a core (2) of the shielded cable (1), an outer terminal (12) to be connected with a shield layer (4) of the shielded cable (1) while at least partly accommodating the inner terminal (11) with a dielectric element (13) provided between the inner and outer terminals (11, 12), at least one metal locking portion (30) formed in an outer surface of the inner terminal (11), and characterized in that at least one locking hole (32) engageable with the metal locking portion (30) is formed in an inner surface of the dietectric element (13) and that the inner surface of the dielectric element (13) is formed with at least one projection (34; 35; 36; 37) projecting from the inner surface of the dielectric element (13) for at least partly filling a clearance between the inner surface of the dielectric element (13) and the inner terminal (11) by coming into contact with the outer surface of the inner terminal (11). A shielding terminal according to claim 1, wherein the at least one metal locking portion (30) is formed in the inner terminal (11) by making at least one cut in the outer surface thereof and bending a cut portion. A shielding terminal according to claim 2, wherein the metal locking portion (30) is made to slantingly project backwards when seen in a direction of insertion of the inner terminal (11) into the dielectric element (13). A shielding terminal according to claim 3 , wherein the inner terminal (11) is formed with at least one resilient contact piece (17) to be brought into contact with a mating terminal and the filling portion (34; 35) at least partly fills the clearance in a direction substantially parallel to an resiliently deforming direction of the resilient contact piece(s) (17). A shielding terminal according to one or more of the preceding claims, wherein the outer terminal (12) is provided with an outer metal locking portion (27) engageable with an auxiliary locking hole (28) provided on an outer surface of the dielectric element (13) so as to lock the dielectric element (13) at least partly inserted in the outer terminal (12). A method for mounting a shielding terminal (10) with an end of a shielded cable (1), comprising the following steps: connecting an inner terminal (11) with a core (2) of the shielded cable (1), connecting an outer terminal (12) with a shield layer (4) of the shielded cable (1) while at least partly accommodating the inner terminal (11) with a dielectric element (13) provided between the inner and outer terminals (11, 12), wherein the inner terminal (11) is locked with the dielectric element (13) by engaging at least one metal locking portion (30) formed in an outer surface of the inner terminal (11) with at least one locking hole (32) formed in an inner surface of the dielectric element (13) at least partly filling a clearance between the inner surface of the dielectric element (13) and the inner terminal (11) by providing at least one protection (34; 35; 36; 37 protecting from the inner surface of the dielectric element 13 forcomin into contact with the outer surface of the inner terminal (11). A method according to claim 6 , wherein the at least one metal locking portion (30) is formed in the inner terminal (11) by making at least one cut in the outer surface thereof and bending a cut portion.

Inventors: KOIDE TAKASHI, KOIDE, TAKASHI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2001
Main classification: H01R9
IPC codes: H01R24, H01R13, H01R103, H01R9