SHIELDED AND SEALED ELECTRIC HARNESS

Abstract

A shielded and sealed electric harness comprises conductors housed in a tubular structure providing protection and shielding, the structure being constituted by a tubular inner textile braid, an intermediate metal tubular braid for electromagnetic shielding, and a corrugated outer sheath having its end adhesively bonded to a heat-shrink endpiece for fastening onto a portion of a connector of a branch joint.

Description

BRIEF DESCRIPTION OF THE DRAWING

The invention can be better understood and other details, characteristics, and advantages thereof appear more clearly on reading the following description made by way of example with reference to the accompanying drawing, in which:

FIG. 1 is a diagrammatic view of an electric harness for an airplane engine; and

FIG. 2 is a diagrammatic axial half-section view of the end of a conductor element of the harness.

MORE DETAILED DESCRIPTION

The harness 10 shown in FIG. 1 comprises a certain number of conductor elements 12 that are interconnected by branch joints 14 and that have a connector 16 at the end of the harness for connection to an electronics system, and connectors 18 for connection to sensors installed in various zones of an airplane engine, e.g. in the zone of a fan mounted at the inlet of a turbojet and in the zone of the compressor of said turbojet.

More precisely, the harness of FIG. 1 comprises a first conductor element 12 having one end fitted with the connector 16 for connection to the electronic system, and having its other end connected via a branch joint 14 to two other conductor elements 12, one of which is fitted at one end with a connector 18 for connection to a sensor and the other of which is connected via another branch joint 14 to two other conductor elements 12 in turn fitted with connectors 18 for connection to sensors.

As can be seen more clearly in FIG. 2, each conductor element 12 comprises one or more electrically conductive wires or cables 20 for transmitting electrical signals between the electronic system and the sensors mounted on the engine, this or these electrically conductive wires or cables being mounted in a tubular protective structure 22 that also provides sealing and that is connected at its ends to a connector 16 or 18 and to a branch joint 14.

According to the invention, the structure 22 comprises a tubular inner textile braid 24 surrounding the conductor(s) 20, a metal tubular braid 26 providing electromagnetic shielding, which braid surrounds the inner textile braid 24, and an outer sheath 28 of corrugated shape, surrounding the shielding metal braid 26.

The inner textile braid 24 is made of aramid fibers of the type sold under the Nomex trademark.

The shielding braid is made of nickel-plated copper, and the outer sheath 28 is made of PTFE.

The end of the sheath 28 is fastened, advantageously by bonding by means of an epoxy adhesive, onto the end of a cylindrical endpiece 30 of heat-shrink plastics material, such as a fluorinated elastomer of the type sold under the Viton trademark, or in a variant a silicone elastomer.

In order to enable it to be adhesively bonded to the endpiece 30, the end of the sheath 28 is subjected to chemical treatment of the sodium ammonia type for eliminating structure fluorine atoms from the sheath.

The heat-shrink endpiece 30 surrounds the end of a cylindrical part 32 that is preferably made of titanium, that is secured to a connector 16 or 18, and that includes a cylindrical tail 34 onto which the end of the metal braid 26 is clamped by means of a metal collar or ferrule 36 of stainless steel, in turn covered by the heat-shrink endpiece 30.

In order to enable the titanium part 32 to provide continuity of electromagnetic shielding, its surface is coated in a layer of chemically-deposited nickel, with the end of the metal braid 26 being clamped thereagainst by the metal collar or ferrule 36.

The end of the endpiece 30 remote from the outer sheath 28 includes an inner annular rim for catching an outer annular rim 40 on the cylindrical tail 34 of the part 32.

Claims

1. A shielded and sealed electric harness, comprising a set of conductor elements fitted at their ends with connectors or branch joints, each conductor element comprising at least one electrically conductive wire or cable mounted in a tubular protective and shielding structure that comprises a tubular inner textile braid and an intermediate metal braid for electromagnetic shielding, wherein the tubular structure also comprises a corrugated outer sheath made of polymer, surrounding the intermediate metal braid and having at least one end secured to a tubular endpiece of heat-shrink material, said tubular endpiece enabling the outer sheath to be fastened onto a connector or a branch joint, and serving to clamp and secure one end of the intermediate metal braid, by means of a metal collar or ferrule onto a tubular metal part of the connector or of the branch joint.

2. A harness according to claim 1, wherein the outer sheath is made of polytetrafluoroethylene.

3. A harness according to claim 2, wherein the end of the outer sheath is chemically treated to enable it to be adhesively bonded onto the endpiece of heat-shrink material.

4. A harness according to claim 1, wherein the heat-shrink endpiece is made of a fluorinated elastomer of the Viton type, or of silicone.

5. A harness according to claim 1, wherein the collar or ferrule for clamping and securing the end of the metal braid on the metal part is made of stainless steel or of copper-nickel alloy.

6. A harness according to claim 1, wherein the intermediate metal braid is made of copper-nickel alloy.

7. A harness according to claim 1, wherein the metal part is made of titanium.

8. A harness according to claim 7, wherein the metal part receives an electrically conductive surface coating so as to provide continuity of electromagnetic shielding.

9. A harness according to claim 1, wherein the inner textile braid is made of aramid fibers.