Device and method for connecting a cable and a connector ensuring the continuity of the electromagnetic shielding

Abstract

A device for joining the end (3a) of a shielded coaxial cable (3) and a metal connector (10), the cable including a peripheral metal braid (4) and an axial conductor (2), and including a conductive overmoulding (5) that at least partially surrounds the end of the shielded cable (3) and one end of the connector (10), the overmoulding making contact with the metal braid (4) and the connector (10), so as to ensure the continuity of the electromagnetic shielding of the connection. A method for producing such a connection is also described.

Claims

1. A device for producing a junction between an end (3a) of a shielded coaxial cable (3) received in an end channel (12) located at an end portion of a metal connector (10), said cable including a peripheral metal braid (4) and an axial conductor (2), said end channel (12) including an exterior peripheral wall at said end portion, the device comprising: a conducting overmolding (5) at least partially surrounding the end (3a) of the shielded coaxial cable (3) and partially surrounding the end channel (12) with an interior surface of an endmost portion of the conducting overmolding directly contacting the exterior peripheral wall of the end channel at the end portion of said metal connector (10), said conducting overmolding extending over said metal connector at least to a distal end face of the shielded coaxial cable transverse to an axis of the shielded coaxial cable so that a contact area between the end of the shielded coaxial cable (3) and the metal connector (10) is covered with said conducting overmolding, said conducting overmolding being in electrical contact with said metal braid (4) and the end channel of said metal connector (10), so as to ensure continuity of electromagnetic shielding of the junction, wherein an endmost portion of said metal braid (4) comprises a first side and an opposite second side, and wherein said end (3a) of the shielded coaxial cable (3) is received in the end channel (12) located at the end portion of said metal connector (10) at least partially surrounding by the conducting overmolding, and the first side of the endmost portion of said metal braid (4) at least partially covering and directly contacting a part of the exterior peripheral wall of said end channel (12) adjacent the endmost portion of the conducting overmolding that directly contacts the exterior peripheral wall at the end portion of the metal connector (10), and the opposite second side of the endmost portion of the metal braid (4) directly contacting the interior surface of a portion of the conducting overmolding immediately adjacent the endmost portion of the conducting overmolding that direct contacts the exterior peripheral wall at the end portion of said metal connector (10).

2. The device according to claim 1, wherein said conducting overmolding (5) includes an intrinsically conductive polymer material.

3. The device according to claim 2, wherein said conducting overmolding includes a binder comprising a silicone elastomer material or an elastomeric plastic.

4. The device according to claim 2, wherein said conducting overmolding includes a filler of approximately 80% conductive particles.

5. The device according to claim 1, wherein said conducting overmolding (5) includes a nonconductive polymer material charged with conductive particles.

6. The device according to claim 5, wherein said conductive particles comprise at least one of an intrinsically inoxidizable or relatively inoxidizable metal, and a metal coated with a conducting layer protecting against oxidation.

7. The device according to claim 6, wherein said conductive particles are chosen from the list consisting of: Silver particles, Graphite-covered Nickel particles, Silver-covered Copper particles, and Silver-covered Aluminum particles.

8. The device according to claim 6, wherein said conductive particles have a diameter between 20 and 40 m.

9. The device according to claim 5, wherein said conductive particles are chosen from the list consisting of: Silver particles, Graphite-covered Nickel particles, Silver-covered Copper particles, and Silver-covered Aluminum particles.

10. The device according to claim 9, wherein said conductive particles have a diameter between 20 and 40 m.

11. The device according to claim 5, wherein said conductive particles have a diameter between 20 and 40 m.

12. The device accordingly to claim 1, wherein said conducting overmolding extends over said connector beyond the distal end face of the shielded coaxial cable.

13. A method for connecting a shielded coaxial cable (3) and a metal connector (10) while ensuring continuity of electromagnetic shielding of the assembly, the method comprising: stripping one end (3a) of the shielded coaxial cable (3) so as to expose an axial conductor (2) and a metal shielding braid (4), an endmost portion of the metal shielding braid (4) comprising a first side and an opposite second side; partially receiving said one end (3a) of the shielded coaxial cable (3) in an end channel (12) of the metal connector (10) so as to leave a portion of the metal shielding braid (4) visible and to put the metal shielding braid (4) and walls of the channel (12) in electrical contact, wherein the first side of the endmost portion of the metal shielding braid (4) at least partially covers and directly contacts an exterior peripheral wall of said end channel (12); and using a conducting material (5) to form a conducting overmolding (5) overmolding a visible exterior part of the metal shielding braid (4) of said one end (3a) of the shielded coaxial cable (3) and at least part of said end channel (12) of the metal connector (10), the conducting material being in electrical contact with the metal connector, the conducting material extending at least to a distal end face of the shielded coaxial cable transverse to an axis of the shielded coaxial cable so that a contact area between the one end of the shielded coaxial cable (3) and the connector (10) is covered with said conducting overmolding (5) at least partially surrounding the one end (3a) of the shielded coaxial cable (3) with an interior surface of the endmost portion of the conducting overmolding directly contacting the exterior peripheral wall of said end channel at the end portion of the metal connector (10) and the first side of the endmost portion of said metal braid (4) at least partially covering and directly contacting a part of the exterior peripheral wall of said end channel (12) adjacent the endmost portion of the conducting overmolding that directly contacts the exterior peripheral wall of said end channel at the end portion of the metal connector (10), and the opposite second side of the endmost portion of the metal braid (4) directly contacting the interior surface of a portion of the conducting overmolding immediately adjacent the endmost portion of the conducting overmolding that direct contacts the exterior peripheral wall of said end channel at the end portion of said metal connector (10).

14. The method accordingly to claim 13, wherein said overmolding conducting material extends beyond the distal end face of the cable.

Description

(1) Embodiments of the invention will be described below, as non-limiting examples, in reference to the appended drawings, in which:

(2) FIG. 1A is an elevation view of a junction between a cable and a connector with overmolding,

(3) FIG. 1B is a diagrammatic axial cross-sectional view A-A of the junction between a cable and a connector with overmolding,

(4) FIG. 1C is an axial cross-sectional view A-A of a first alternative of a junction between a cable and a connector with overmolding,

(5) FIG. 1D is an axial cross-sectional view A-A of a second alternative junction between a cable and a connector with overmolding.

(6) In this example, as shown in particular in FIGS. 1A to 1D, the device according to the invention comprises: the end 3a of the coaxial cable 3, said cable being shielded using a metal braid 4 surrounding at least one axial electric conductor 2 (in broken lines); the metal braid 4 may in particular be made from copper, aluminum or steel; a metal conductor 10 that can be connected to a system that is electrically powered and that itself is electromagnetically protected; this electrical connector includes an end channel 12 in which said end 3a of the shielded cable 3 engages; the conducting overmolding 5 that overmolds the end 3a of the cable and part of the channel of the connector 10; this overmolding is advantageously done from a conducting material described below, so as to ensure 360 grounding guaranteeing the equipotentiality of the metal braid 4 and the connector 10; as shown in FIGS. 1A to 1D, the overmolded part 5 has a substantially cylindrical shape.

(7) After having inserted the end 3a of the cable 3 in the free space of the channel 12, the metal braid 4 can: abut against the end walls of the channel 12 of the connector 10, as shown in FIG. 1B; cover the walls of the channel 12 of the connector 10, as shown in FIG. 1C; be inserted into the space delimited by the walls of the channel 12 of the connector 10, as shown in FIG. 1D.

(8) The overmolded part 5 covers the end 3a of the cable 3 and therefore the metal braid 4, as well as at least part of the channel 12 of the connector 10, which advantageously makes it possible to ensure 360 grounding.

(9) The overmolding 5 may be done:

(10) either from an injectable polymer material or a thermoplastic material such as Santoprene, filled with conductive particles,

(11) or an organic intrinsically conducting polymer (ICP) material, the goal being to achieve a resistivity of approximately 5 m/cm.

(12) Advantageously, the overmolding may include a binder comprising a silicone elastomer material or an elastomeric plastic, which is preferably injectable.

(13) Advantageously, the overmolding may include a filler of conductive particles comprised between x and y %, preferably approximately 80% so as to achieve the aforementioned low resistivity.

(14) In the case of a non-conductive polymer binder, the conductive particles may be:

(15) Silver particles,

(16) Graphite-covered Nickel particles,

(17) Silver-covered Copper particles, or

(18) Silver-covered Aluminum particles.

(19) The use of a noble metal such as Silver makes it possible to avoid oxidation. These particles have a diameter comprised between 20 and 40 m.