A shielding terminal

Abstract: [Object] To improve shielding characteristics. [Solution] An inner terminal 11 is accommodated in an accommodating portion 20 of an outer terminal 12 via a dielectric element 13. A core 2 of a shielded cable 1 is fastened to an inner fastening portion 18 of the inner terminal 11 outside the outer terminal 12, and then the inner terminal 11 is inserted into the dielectric element 13. A braided wire 4 is folded back around an end of a sheath 5, and an outer fastening portion 22 of the outer terminal 12 is fastened to a folded portion 4A thereof. A covering wall portion 21 in which only the upper surface is open is provided between the accommodating portion 20 and the outer fastening portion 22 of the outer terminal 12, and the inner fastening portion 18 is located in the covering wall portion 21. Upon the completion of crimping, the shielding terminal 10 is fixed by inserting the cover 14 into the opening 21A of the covering wall portion 21 and thereby elastically holding the outer fastening portion 22 by holding pieces 39 of a clip portion 37 from opposite lateral sides. As a result, the core 2 has its fastened portion and a portion near it covered on four sides by conductive members.

Description: The present invention relates to a shielded or shielding terminal to be connected with an end of a shielded cable. US-A-5,667,404 discloses a co-axial connector for a high frequency cable formed by a central conductor 6, an external conductor 7 and an external insulator 26, the connector comprising a center pin 5 and an earth metal fittings 4 accommodating the center pin with an insulating bushing 3 provided between the center pin and the earth metal fittings. The earth metal fittings comprises a cylindrical part 17 with is C-shaped in sectional view and a pressurized barrel part 15 which is U-shaped in sectional view. An entrance of the cylindrical part allows the center pin to be inserted into a center pin's hole 11 of the insulating bushing from the rear of the insulating bushing until a flange part 13 attaches to steps 40. As a shielding terminal of this type is known the one shown in FIGS. 6 and 7. This shielding terminal is comprised of an inner terminal a to be connected with a mating terminal and an outer terminal c in the form of a rectangular tube accommodating the inner terminal via a dielectric element b. A core fastening portion h provided in the inner terminal a is crimped for the connection with the end of a core e of a shielded cable d, whereas a braided wire fastening portion i and a sheath fastening portion j provided at the outer terminal a are crimped for the connection with an end of a braided wire f and an end of a sheath g, respectively. When the shielding terminal is crimped by a terminal mounting apparatus, the core e, the braided wire f and the sheath g are simultaneously connected. It is essential to form windows k in the upper and lower surfaces of the outer terminal c particularly in order to crimp the core fastening portion h of the inner terminal a accommodated in the outer terminal c by bringing a crimper thereto. This means that a portion of the fastened end of the core e has its upper and lower surfaces exposed through the windows k, thereby undesirably reducing shielding characteristics such as a radiation characteristic. Document US-A-5 145 409 discloses a terminal according to the preamble of claim 1. In view of the above problem, an object of the present invention is to provide a shielding terminal having improved shielding characteristics. This object is solved according to the invention by a shielding terminal according to claim 1. Preferred embodiments are subject of the dependent claims. According to the invention, there is provided a shielding terminal according to claim 1. The shield layer is preferably a braided wire. Since the exposed portion of the inner terminal near its fastening portion to the core is covered by the cover member, shielding characteristics such as a radiation characteristic can be improved. According to a preferred embodiment of the invention, the cover member is detachably mountable on a fastening portion of the outer terminal to the shield layer. Accordingly, the shielding terminal can be made smaller and simpler by simplifying the mount construction and the like. Further preferably, the outer terminal is to be connected with a braided wire as the shield layer. According to a further preferred embodiment, the inner terminal is crimped for the connection with the core outside the outer terminal, the outer terminal includes the fastening portion for fastening the shield layer, preferably the braided wire, folded back around the sheath together with the sheath and/or a covering wall portion for substantially covering the fastening portion of the inner terminal to the core on three sides, and the cover member is so formed as to substantially close an opening of the covering wall portion and is detachably mountable on the fastening portion of the outer terminal. The shielding terminal can be made smaller, a crimper is allowed to have a simple construction, and the fastening portion of the inner terminal to the core can be covered on four sides by the covering wall portion of the outer terminal and the cover member. Thus, shielding characteristics can be more securely improved. Preferably, a portion of the cover member mountable on the fastening portion of the outer terminal is formed into a clip for elastically holding the fastening portion. Since the mount portion of the cover member is in the form of a clip, the cover member can be easily and strongly mounted. Most preferably, the cover comprises a covering portion being positioned in a position radially inward and longitudinally displaced from a radially outward surface of the outer terminal, whereby the outer terminal comprises an edge portion, which can preferably act as an engaging portion for a locking portion of an external housing. 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 in which: FIG. 1 is an exploded perspective view of one embodiment of the invention, FIG. 2 is an exploded side view of the embodiment, FIG. 3 is a vertical section showing a state before a cover is mounted, FIG. 4 is a perspective view showing the state of FIG. 3, FIG. 5 is a perspective view showing a state where the cover is mounted, FIG. 6 is a perspective view of a prior art shielding terminal, and FIG. 7 is a plan view of the prior art shielding terminal. Hereinafter, one embodiment of the invention is described with reference to FIGS. 1 to 5. In this embodiment is illustrated a male shielding terminal 10, which is used by being fastened to an end of a shielded cable 1. The shielded cable 1 has such a known structure that a core 2 formed e.g. by twisting a plurality of strands, an insulating layer 3, a shield layer or braided wire 4 and a sheath 5 made e.g. of rubber or like material are coaxially placed on top of another in this order from the inside as shown in FIGS. 1 and 4. In this embodiment is performed such an end processing that the braided wire 4 exposed by stripping an end of the sheath 5 is folded back around the sheath 5, and an exposed end of the insulating layer 3 is cut off to at least partly expose the core 2. The shielding terminal 10 is roughly comprised of an inner terminal 11, an outer terminal 12, a dielectric element 13 and a cover 14 as shown in FIGS. 1 and 2. The inner terminal 11 is formed into a male terminal e.g. by bending a conductive metal plate, and is provided with a tab portion 16 to be connected with a mating female inner terminal (not shown), biting projections 17 which bite in or are inserted or cut into the inner wall of the dielectric element 13 when being pushed thereinto, and an inner fastening portion 18 to be crimped for the connection with the core 2 of the shielded cable 1. The tab portion 16, the biting projections 17 and the inner fastening portion 18 are arranged in this order from the leading end side of the inner terminal 11. The inner fastening portion 18 includes a pair of fastening pieces 18A and is initially laterally or open upward. The outer terminal 12 is likewise formed e.g. by bending a conductive metal plate and is provided with an accommodating portion 20 in the form of a substantially rectangular tube, a covering wall portion 21 having an open upper surface, and an outer fastening portion 22 to be crimped for the connection with a folded portion 4A of the braided wire 4 of the shielded cable 1. The accommodating portion 20, the covering wall portion 21 and the outer fastening portion 22 are arranged in this order from the leading end side of the outer terminal 12. In the upper wall of the accommodating portion 20 is formed a metal locking portion 24 for locking the dielectric element 13 so as to prevent it from coming out through the front opening of the accommodating portion 20. The metal locking portion 24 is formed by cutting a portion of the upper wall of the accommodating portion 20 and bending this cut portion inwardly so as to extend obliquely backward. Further, a stopper 25 for coming into abutment against the rear surface of the dielectric element 13 to prevent it from moving backward stands on the bottom wall of the accommodating portion 20 (shown in detail in FIG. 3). In the left and right side walls of the accommodating portion 20 are formed contact pieces 26 which can be elastically brought or bringable into contact with a mating female outer terminal. In other words, the covering wall portion 21 is comprised of the bottom, left and right walls to be substantially closed on three sides, and the inner fastening portion 18 of the inner terminal 11 fastened to the core 2 of the shielded cable 1 is located substantially inside the covering wall portion 21. Stabilizers 27 project transversely outward from the upper edges of the left and right side walls of the covering wall portion 21. The outer fastening portion 22 similarly includes a pair of fastening pieces 22A and is initially open upward. The dielectric element 13 is made of an insulating material such as a synthetic resin, and functions to electrically insulate the inner and outer terminals 11, 12 to each other. The dielectric element 13 is fittable into a rear end side of the accommodating portion 20 of the outer terminal 12, and is formed with an accommodating hole 30 for at least partially accommodating the inner terminal 11 between the base end of the tab portion 16 and a portion thereof where the biting projections 17 are provided. A locking hole 31 into which the metal locking portion 24 of the outer terminal 12 is fittable is formed in the upper surface of the dielectric element 13, and a contact portion 32 to be brought into contact with the stopper 25 of the outer terminal 12 is formed in the lower surface thereof. The cover 14 is formed into such a shape as shown in FIG. 4 e.g. by bending a conductive metal plate. More specifically, the cover 14 has a covering portion 35 for substantially completely covering from an opening 21A in the upper surface of the covering wall portion 21 of the outer terminal 12 to the crimped outer fastening portion 22. Left and right edges of the covering portion 35 are bent downward so as to also function as guides, and a pair of hanging portions 36 are so formed at the rear end of the covering portion 35 as to substantially cover rear parts of the left and right walls of the covering wall portion 21. A clip portion 37 is continuously formed at the rear end of the covering portion 35. The clip portion 37 includes a base plate 38 located slightly above the covering portion 35 and a pair of holding pieces 39 hanging downward from the left and right edges of the base plate 38. The holding pieces 39 are elastically deformable in directions away from each other in order to elastically hold the crimped outer fastening portion 22. The bottom ends of the respective holding pieces 39 are bent slightly outward, and biting projections 40 which bite into the outer surface of the outer fastening portion 22 are formed at the front and rear edges of the inner surface of the respective holding pieces 39. An operation of fastening the shielding terminal 10 to the end of the shielded cable 1 is performed in the following procedure. End processing is applied to the shielded cable 1 as already described. First, the fastening pieces 18A of the inner fastening portion 18 of the inner terminal 11 are crimped and fastened to the end of the core 2 of the shielded cable 2. Subsequently, the dielectric element 13 is inserted into the accommodating portion 20 of the outer terminal 12 from front or from a side substantially opposed to the cable insertion side. The dielectric element 13 is pushed while elastically deforming the metal locking portion 24. When the contact portion 32 comes into contact with the stopper 25 as shown in FIG. 3, the metal locking portion 24 is at least partly restored to its original shape, thereby being slipped into the locking hole 31, with the result that the dielectric element 13 is substantially fixed in a specified position at the rear end of the accommodating portion 20. Subsequently, the inner terminal 11 is inserted into the accommodating portion 20 of the outer terminal 12, and maneuvered by a jig inserted through the opening 21 A in the upper surface of the covering wall portion 21 to push the tab portion 16 into the accommodating hole 30 of the dielectric element 13. During this stage, the biting projections 17 bite in the inner wall of the accommodating hole 30, with the result that the inner terminal 11 is fixed while the tab portion 16 is at least partly projecting from the dielectric element 13 as shown in FIG. 3. In this way, the inner terminal 11 is accommodated in the outer terminal 12 via the dielectric element 13. Here, the inner fastening portion 18 of the inner terminal 11 is located in the wall covering portion 21 of the outer terminal 12, and the folded portion 4A of the braided wire 4 of the shielded cable 1 is located in the outer fastening portion 22 of the outer terminal 12. Next, the open outer fastening portion 22 is crimped by a crimper. The both fastening pieces 22A are crimped to substantially surround the folded portion 4A of the braided wire 4 in such a manner that the end of one fastening piece 22A is placed on that of the other fastening piece 22A, and to fasten the folded portion 4A of the braided wire 4 and the end of the sheath 5 together. At this time, the left and right surfaces of the crimped outer fastening portion 22 are substantially parallel to each other. By the above operation, the inner and outer terminals 11, 12 are mounted on the end of the shielded cable 1 as shown in FIG. 4. Even in this state, the shielding terminal 10 sufficiently fulfils its functions and has particular advantages. Specifically, since the braided wire 4 and the sheath 5 are fastened by the single outer fastening portion 22 by folding the braided wire 4 back around the sheath 5, the length of the shielding terminal 10 can be shortened as compared with conventional ones in which the braided wire and the sheath are separately fastened. Further, since the inner terminal 11 is mounted in advance outside the outer terminal 12 and the crimped inner fastening portion 18 is located in the covering wall portion 21 of the outer terminal 12 to be surrounded on three sides, shielding characteristics such as a radiation characteristic can be improved as compared with conventional shielding terminals in which both upper and lower surfaces are open. In this embodiment, the cover 14 is further provided. The cover 14 is inserted into the opening 21A in the upper surface of the covering wall portion 21 of the outer terminal 12 as indicated by an arrow in FIG. 4 after the shielded cable 10 is assembled as described above. At this stage, the clip portion 37 of the cover 14 is pushed while the holding pieces 39 thereof are widened against elastic forces to forcibly hold the crimped outer fastening portion 22 from opposite lateral sides. The clip portion 37 stops being pushed when the base plate 38 comes into contact with the upper surface of the outer fastening portion 22, and is fixed by the holding pieces 39 elastically holding the left and right surfaces of the outer fastening portion 22 while the biting projections 40 bite in these surfaces. When the cover 14 is mounted as above, the covering portion 35 completely covers from the opening 21A in the upper surface of the covering wall portion 21 to the outer fastening portion 22, and the left and right hanging portions 36 cover open rear portions of the left and right walls of the covering wall portion 21 as shown in phantom line of FIG. 3 and in FIG. 5. As a result, the inner fastening portion 18 of the inner terminal 11 fastened to the core 2 of the shielded cable 1 is substantially covered on four sides by the cover 14 and the covering wall portion 21 of the outer terminal 12. As described above, according to the foregoing embodiment, by providing the cover 14, the core 2 exposed from the braided wire 4 can have its fastened portion and a portion near it substantially covered on four sides by the conductive members including the covering wall portion 21 of the outer terminal 12. Therefore, shielding characteristics such as a radiation characteristic can be remarkably improved. Since the cover 14 is mounted on the outer fastening portion 22 of the outer terminal 12 by the clip portion 37, it can be simply mounted and fitted in the outer terminal 12, with the result that the shielding terminal 10 is allowed to have a small size as a whole. Further, the shielding terminal 10 can be securely grounded by employing a clip-lock construction. Furthermore, since the covering portion 35 of the cover 14 is located in a position below the upper surface of the accommodating portion 20 of the outer terminal 12 as shown in FIG. 5, a rear edge 42 of the upper surface of the accommodating portion 20 can act as an engaging portion to be engaged with a resin locking portion provided in a cavity of a housing when the shielding terminal 10 is accommodated into the cavity. < Other Embodiments > The present invention is not limited to the described and illustrated embodiment but, for example, the following embodiments are also embraced by the technical scope of the present invention as defined in the claims. Besides the following embodiments, a variety of other changes can be made without departing from the scope of the invention as defined in the claims. (2) Although the male shielding terminal is illustrated in the foregoing embodiment, the present invention is similarly applicable to female shielding terminals. LIST OF REFERENCE NUMERALS 1 Shielded Cable 2 Core 3 Insulating Layer 4 Braided Wire 4A Folded Portion 5 Sheath 10 Shielding Terminal 11 Inner Terminal 12 Outer Terminal 13 Dielectric Element 14 Cover 18 Inner Fastening Portion 20 Accommodating Portion 21 Covering Wall Portion 21 A Opening (of the Covering Wall Portion 21) 22 Outer Fastening Portion 35 Covering Portion 37 Clip Portion 39 Holding Piece

Claims: A shielding terminal connectable with an end of a shielded cable (1), the cable formed by coaxially arranging a core (2) and a shield layer (4) with an insulating layer (3) therebetween and covering the outer surface of the shield layer (4) by a sheath (5), the shielding terminal comprising: an inner terminal (11) having a fastening portion (18) to be crimped for the connection with the core (2), and an outer terminal (12) to be connected with the shield layer (4) while accommodating the inner terminal (11) with a dielectric element (13) provided between the inner and outer terminals (11, 12), characterized in that , the shielding terminal further comprising a cover member (14) for substantially covering an exposed portion of the inner terminal (11) near its fastening portion (18) to the core (2), and the outer terminal (12) comprises a covering wall portion (21) for covering the fastening portion (18) of the inner terminal (11) to the core (2) on three sides. A shielding terminal according to claim 1, wherein the cover member (14) is detachably mountable on a fastening portion (22) of the outer terminal (12) to the shield layer (4). A shielding terminal according to one or more of the preceding claims, wherein the outer terminal (12) is to be connected with a braided wire as the shield layer (4). A shielding terminal according to one or more of the preceding claims, wherein: the inner terminal (11) is crimped for the connection with the core (2) outside the outer terminal (12). A shielding terminal according to one or more of the preceding claims, wherein the outer terminal (12) includes the fastening portion (22) for fastening the shield layer (4) folded back around the sheath (5) together with the sheath (5). A shielding terminal according to claim 5, wherein the cover member (14) is so formed as to substantially close an opening of the covering wall portion (21) and is detachably mountable on the fastening portion (18) of the outer terminal (12). A shielding terminal according to one or more of the preceding claims, wherein a portion of the cover member (14) mountable on the fastening portion (22) of the outer terminal (12) is formed into a clip (37) for elastically holding the fastening portion (22). A shielding terminal according to one or more of the preceding claims, wherein the cover (14) comprises a covering portion (35) being positioned in a position radially inward and longitudinally displaced from a radially outward surface of the outer terminal (12) whereby the outer terminal (12) comprises an edge portion (42), which can preferably act as an engaging portion for a locking portion of an external housing.

Inventors: AOYAMA MASAHIKO, KOIDE TAKASHI, SAITO MASASHI, AOYAMA, MASAHIKO, KOIDE, TAKASHI, SAITO, MASASHI, Aoyama, Masahiko, Sumitomo Wiring Systems, Ltd., Koide, Takashi, Sumitomo Wiring Systems, Ltd., Saito, Masashi, Sumitomo Wiring Systems, Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1999
Main classification: H01R13
IPC codes: H01R24, H01R4, H01R43, H01R9