Wire harness

Abstract: Insulatedly coated wires (10) each coated with a metal foil of good electric conductivity and a metal foil of high magnetic permeability to form an electrostatic shielding layer (20) and a magnetic shielding layer (30), are bundled and are connected at their opposite ends to connectors. Each wire is adapted to be shielded with the metal foils in place of the conventional braided tube, thereby providing an easy-to-manufacture wire harness having good shielding effects adjacent the connectors.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a wire harness for use in electronic equipments, copying machines, facsimiles, automotive vehicles, and the like and, more particularly, to a wire harness which is easily manufactured and is excellent in shielding properties. Description of the Background Art In the past, the wire bundle portion of a wire harness has been coated with a braided tube formed of a conductive material to eliminate the influences of noises generated within an automotive vehicle or the like. To manufacture such a wire harness with a shield, it is necessary to insert the wire harness into the braided tube of predetermined length corresponding to the wire harness after the production of the wire harness, resulting in more working operations of necessity. For a wire harness having one end connected to a master connector and the other end connected to a plurality of secondary connectors, a need exists to insert each bundle of wires connected to a secondary connector into the braided tube, resulting in much more working operations. Further, the braided tube must be spaced apart from a terminal of the connector in order to insulate the braided tube and the terminal from each other. It is, however, difficult to correctly position the braided tube relative to the terminal in the foregoing manufactoring method. For this reason, the braided tube is spaced relatively greatly away from the terminal of the connector in consideration for the degree of freedom of manufactoring. this might result in insufficient shielding effect of the braided tube adjacent the terminal. US-A-4,835,394 discloses a batch cable of a multiconductor. This known cable includes a plurality of individually shielded wires lined up in a row. The shielding for each of said plurality of shielded wires is provided by a single shielding layer made of conductive material. The individually shielded wires are embedded in a dielectric layer so that the individually shielded layers are not in contact with each other. The dielectric layer is then surrounded by a double-fold shielding layer again made of a conductive material. DE-B-2,654,880 discloses a three-layer shielding structure surrounding a group of wires said shielding structure consisting of an inner metal shield of good conductivity, covered by a metal shield of high magnetic permeability, an an outermost polyester layer covering the metal shield of high magnetic permeability. US-A-4,340,771 discloses a shielded cable with a single metallic shielding tape composed of two layers aluminium or copper bonded to both surfaces of an iron steel layer (sandwich structure). The outermost layer on both sides of the shielding tape is a plastic coating layer. The shielding tape is rapped around a bundle of wires dividing them into two groups. It is an object of the present invention to provide a wire harness which can be manufactured in fewer working operations and which provides good shielding effects adjacent connectors. This object is solved by a wire harness as defined in claims 1. According to the present invention, a wire harness comprises: a plurality of shielded wires formed into a bundle, and connectors connected respectively to opposite ends of the shielded wires, each of the shielded wires including an insulatedly coated wire, an electrostatic shielding layer, and a magnetic shielding layer, the electrostatic shielding layer and the magnetic shielding layer covering the insulatedly coated wire throughout its length, the electrostatic shielding layer being formed of a first metal foil of good electric conductivity, the magnetic shielding layer being formed of a second metal foil of high magnetic permeability. According to another aspect of the present invention, a wire harness comprises: a plurality of shielded wires formed into a bundle, and connectors connected respectively to opposite ends of the shielded wires, each of the shielded wires including an insulatedly coated wire, an electrostatic shielding layer, and a magnetic shielding layer, the electrostatic shielding layer and the magnetic shielding layer covering the insulatedly coated wire throughout its length, the electrostatic shielding layer being formed of a metal foil of good electric conductivity, the magnetic shielding layer being formed of a first metal layer of high magnetic permeability plated or deposited on the metal foil of good electric conductivity. The wire harness is manufactured in normal process steps by using the insulatedly coated wires each coated with the metal foil of good electric conductivity and the metal foil of high magnetic permeability. Since each of the insulatedly coated wires is shielded as long as its ends, the shielding effects from electric and magnetic fields are not lowered adjacent the connectors. As above described, the wire harness of the present invention in which each of the insulatedly coated wires is shielded with the metal foil in place of the conventional braided tube, is easily manufactured and provides good shielding effects adjacent the connectors. Further, each of the insulatedly coated wires or the bundle thereof is coated with the metal foil of high magnetic permeability. This also provides magnetic shielding effects. Further objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of a wire harness according to a first preferred embodiment of the present invention; Fig. 2 is a perspective view of a wire for use in the first preferred embodiment; Fig. 3 is a sectional view of Fig. 2; and Fig. 4 is a sectional view showing a second preferred embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, preferred embodiments will be described hereinafter according to the present invention. Referring to Fig. 1, a wire harness according to a first preferred embodiment of the present invention comprises a plurality of shielded wires 1 having opposite ends connected to connectors 2 and bundled with adhesive tapes 3. Each of the shielded wires 1 is formed with an insulatedly coated wire 10 including several core wires (copper wires) 11 and an insulative resin 12 covering the core wires 11, an electrostatic shielding layer 20, and a magnetic shielding layer 30. The electrostatic shielding layer 20 and the magnetic shielding layer 30 are formed of a metal foil of good electric conductivity and a metal foil of high magnetic permeability, respectively, which cover the insulatedly coated wire 10 throughout its length, as shown in Fig. 2. The electrostatic shielding layer 20 is bonded to the insulatedly coated wire 10 with an adhesive (not shown) and the magnetic shielding layer 30 is bonded to the electrostatic shiedling layer 20 with an adhesive (not shown). The electrostatic shiedling layer 20 and the magnetic shielding layer 30 are of double layer construction consisting of metal layers 21, 31 and polyester layers 22, 32, respectively, as shown in Fig. 3. The double layer construction is adopted for the purpose of reinforcing the metal layers with the polyester layers for enhancement of workability because a single metal layer, if provided, is very disadvantageous in strength. The metal layer 21 is typically made of a metal of good electric conductivity such as copper and aluminum. The metal layer 31 is typically made of a metal of high magnetic permeability such as iron and nickel. Preferably, the respective metal layers 21 and 31 are 20 µm or less in thickness. The thicker the metal layers 21 and 31 are, the greater the shielding effects thereof are. However, too great thickness of the metal layers 21 and 31 impairs the flexibility of the wire harness. Polyimide layers or polyvinyl chloride layers may be substituted for the polyester layers 22 and 32. Polyester layers are, however, more advantageous in consideration for costs and strength. The electrostatic shielding layer 20 having the metal foil of good electric conductivity and the magnetic shielding layer 30 having the metal foil of high magnetic permeability coat the wire 10 independently in the first preferred embodiment, which requires two working steps. In a second preferred embodiment according to the present invention, the metal foils may be formed integrally to reduce the working steps. Specifically, metal of high magnetic permeability should be plated or deposited on an electrostatic shielding layer 23 of good electric conductivity consisting of a metal layer 24 and a polyester layer 25 to form a magnetic shielding layer 33, as shown in Fig. 4. The metal layer 24 is made of copper or aluminum and the magnetic shielding layer 33 is made of nickel or iron.

Claims: A wire harness, comprising: a plurality of shielded wires (1) formed into a bundle, and connectors (2) connected respectively to opposite ends of said shielded wires (1), each of said shielded wires (1) including an insulatedly coated wire (10), an electrostatic shielding layer (20; 23) covering said insulatedly coated wire (10) throughout its length, and a magnetic shielding layer (30; 33) covering said electrostatic shielding layer (30; 33) throughout its length, said electrostatic shielding layer (20; 23) being formed of a first metal foil of good electric conductivity and said magnetic shielding layer (30; 33) being formed of a second metal foil of high magnetic permeability, and said pluraltiy of shielded wires (1) are bundled with adhesive tapes (3). The wire harness of claim 1, wherein said electrostatic shielding layer (20; 23) is of double layer construction consisting of a first metal layer (21; 24) and a first polyester layer (22; 25). The wire harness of claim 1 or 2, wherein said electrostatic shielding layer (23) and said magnetic shielding layer (33) are integrally formed, said second metal foil (23) of high magnetic permeability being plated or evaporated on said first metal foil (24) of good electric conductivity. The wire harness of any of claims 1 or 2, wherein said magnetic shielding layer (30; 70) is of double layer construction consisting of a second metal layer (31) and a second polyester layer (32). The wire harness of anyone of the preceding claims, wherein said first metal layer (21; 24) is made of copper or aluminum, and said second metal layer (31) is made of iron or nickel. The wire harness of any of the preceding claims, wherein each of said first and second metal layers (21, 31; 24, 31) is not more than 20 µm in thickness.

Inventors: HASHIMOTO MASAYOSHI, MIZUTANI KENJI, YAMANO YOSHIAKI, HASHIMOTO, MASAYOSHI, MIZUTANI, KENJI, YAMANO, YOSHIAKI, HASHIMOTO, MASAYOSHI, C/O SUMITOMO WIRING SYSTEMS, MIZUTANI, KENJI, C/O SUMITOMO WIRING SYSTEMS, LTD, YAMANO, YOSHIAKI, C/O SUMITOMO WIRING SYSTEMS, LTD
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1993
Main classification: H01B11
IPC codes: H01B11, H01B7